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  • Articles  (30,820)
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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Stochastic environmental research and risk assessment 10 (1996), S. 1-15 
    ISSN: 1436-3259
    Keywords: Spacings ; quantiles ; generalized Pareto distribution ; log-logistic distribution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Energy, Environment Protection, Nuclear Power Engineering , Geography , Geosciences
    Notes: Abstract The maximum product of spacings (MPS) method is discussed from the standpoint of information theory. MPS parameter and quantile estimates for the generalized Pareto distribution and the two parameter log-logistic distribution are compared with the maximum likelihood(ML) and probability weighted moment (PWM) estimates.
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  • 2
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    Stochastic environmental research and risk assessment 10 (1996), S. 17-37 
    ISSN: 1436-3259
    Keywords: Diffusion ; network ; reservoir ; power law
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Energy, Environment Protection, Nuclear Power Engineering , Geography , Geosciences
    Notes: Abstract A diffusion approximation for a network of continuous time reservoirs with power law release rules is examined. Under a mild assumption on the inflow processes, we show that for physically reasonable values of the power law constants, the system of processes converges to a multi-dimensional Gaussian diffusion process. We also illustrate how the limiting Gaussian process may be used to compute approximations to the original system of reservoirs. In addition, we study the quality of our approximations by comparing them to results obtained by simulations of the original watershed model. The simulations offer support for the use of the approximation developed here.
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  • 3
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    Stochastic environmental research and risk assessment 10 (1996), S. 39-63 
    ISSN: 1436-3259
    Keywords: Saturated flow ; rainfall ; groundwater monitoring
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Energy, Environment Protection, Nuclear Power Engineering , Geography , Geosciences
    Notes: Abstract A numerical experiment of flow in variably saturated porous media was performed in order to evaluate the spatial and temporal distribution of the groundwater recharge at the phreatic surface for a shallow aquifer as a function of the input rainfall process and soil heterogeneity. The study focused on the groundwater recharge which resulted from the percolation of the excess rainfall for a 90-days period of an actual precipitation record. Groundwater recharge was defined as the water flux across the moving phreatic surface. The observed spatial non-uniformity of the groundwater recharge was caused by soil heterogeneity and is particularly pronounced during the stage of recharge peak (substantial percolation stage). During that stage the recharge is associated with preferential flow paths defined as soil zones of locally higher hydraulic conductivity. For the periods of low percolation intensity the groundwater recharge was exhibiting more uniform spatial characteristics. The temporal distribution of the recharge was found to be a function of the frequency and intensity of the rainfall events. Application of sampling design demonstrates the joint influence of the spatial and temporal recharge variability on the cost-effective monitoring of groundwater potentiometric surfaces.
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  • 4
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    Stochastic environmental research and risk assessment 10 (1996), S. 65-85 
    ISSN: 1436-3259
    Keywords: Streamflow ; drought ; tree-ring data ; renewal model ; geometric variables
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Energy, Environment Protection, Nuclear Power Engineering , Geography , Geosciences
    Notes: Abstract It is shown that runs of low-flow annual streamflow in a coastal semiarid basin of Central California can be adequately modelled by renewal theory. For example, runs of below-median annual streamflows are shown to follow a geometric distribution. The elapsed time between runs of below-median streamflow are geometrically distributed also. The sum of these two independently distributed geometric time variables defines the renewal time elapsing between the initiation of a low-flow run and the next one. The probability distribution of the renewal time is then derived from first principles, ultimately leading to the distribution of the number of low-flow runs in a specified time period, the expected number of low-flow runs, the risk of drought, and other important probabilistic indicators of low-flow. The authors argue that if one identifies drought threat with the occurrence of multiyear low-flow runs, as it is done by water supply managers in the study area, then our renewal model provides a number of interesting results concerning drought threat in areas historically subject to inclement, dry, climate. A 430-year long annual streamflow time series reconstructed by tree-ring analysis serves as the basis for testing our renewal model of low-flow sequences.
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  • 5
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    Stochastic environmental research and risk assessment 10 (1996), S. 87-106 
    ISSN: 1436-3259
    Keywords: Climate change ; daily precipitation modelling ; generalized linear models ; iteratively reweighted least squares ; spline functions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Energy, Environment Protection, Nuclear Power Engineering , Geography , Geosciences
    Notes: Abstract The precipitation amounts on wet days at De Bilt (the Netherlands) are linked to temperature and surface air pressure through advanced regression techniques. Temperature is chosen as a covariate to use the model for generating synthetic time series of daily precipitation in a CO2 induced warmer climate. The precipitation-temperature dependence can partly be ascribed to the phenomenon that warmer air can contain more moisture. Spline functions are introduced to reproduce the non-monotonous change of the mean daily precipitation amount with temperature. Because the model is non-linear and the variance of the errors depends on the expected response, an iteratively reweighted least-squares technique is needed to estimate the regression coefficients. A representative rainfall sequence for the situation of a systematic temperature rise is obtained by multiplying the precipitation amounts in the observed record with a temperature dependent factor based on a fitted regression model. For a temperature change of 3°C (reasonable guess for a doubled CO2 climate according to the present-day general circulation models) this results in an increase in the annual average amount of 9% (20% in winter and 4% in summer). An extended model with both temperature and surface air pressure is presented which makes it possible to study the additional effects of a potential systematic change in surface air pressure on precipitation.
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  • 6
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    Stochastic environmental research and risk assessment 10 (1996), S. 107-126 
    ISSN: 1436-3259
    Keywords: Gaussian process ; spatial correlation ; anisotropy ; Fourier transform ; Gauss-Newton ; ECM ; measurement error ; signal extraction ; irregular data
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Energy, Environment Protection, Nuclear Power Engineering , Geography , Geosciences
    Notes: Abstract This paper is concerned with developing computational methods and approximations for maximum likelihood estimation and minimum mean square error smoothing of irregularly observed two-dimensional stationary spatial processes. The approximations are based on various Fourier expansions of the covariance function of the spatial process, expressed in terms of the inverse discrete Fourier transform of the spectral density function of the underlying spatial process. We assume that the underlying spatial process is governed by elliptic stochastic partial differential equations (SPDE's) driven by a Gaussian white noise process. SPDE's have often been used to model the underlying physical phenomenon and the elliptic SPDE's are generally associated with steady-state problems. A central problem in estimation of underlying model parameters is to identify the covariance function of the process. The cumbersome exact analytical calculation of the covariance function by inverting the spectral density function of the process, has commonly been used in the literature. The present work develops various Fourier approximations for the covariance function of the underlying process which are in easily computable form and allow easy application of Newton-type algorithms for maximum likelihood estimation of the model parameters. This work also develops an iterative search algorithm which combines the Gauss-Newton algorithm and a type of generalized expectation-maximization (EM) algorithm, namely expectation-conditional maximization (ECM) algorithm, for maximum likelihood estimation of the parameters. We analyze the accuracy of the covariance function approximations for the spatial autoregressive-moving average (ARMA) models analyzed in Vecchia (1988) and illustrate the performance of our iterative search algorithm in obtaining the maximum likelihood estimation of the model parameters on simulated and actual data.
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  • 7
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    Stochastic environmental research and risk assessment 10 (1996), S. 127-150 
    ISSN: 1436-3259
    Keywords: Rainfall estimation ; indicator cokriging ; rain gage measurements
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Energy, Environment Protection, Nuclear Power Engineering , Geography , Geosciences
    Notes: Abstract Indicator cokriging (Journel 1983) is examined as a tool for real-time estimation of rainfall from rain gage measurements. The approach proposed in this work obviates real-time estimation of real-time statistics of rainfall by using ensemble or climatological statistics exclusively, and reduces computational requirements attendant to indicator cokriging by employing only a few auxiliary cutoffs in estimation of conditional probabilities. Due to unavailability of suitable rain gage measurements, hourly radar rain fall data were used for both indicator covariance estimation and a comparative evaluation. Preliminary results suggest that the indicator cokriging approach is clearly superior to its ordinary kriging counterpart, whereas the indicator kriging approach is not. The improvement is most significant in estimation of light rainfall, but drops off significantly for heavy rainfall. The lack of predictability in spatial estimation of heavy rainfall is borne out in the integral scale of indicator correlation: peaking to its maximum for cutoffs near the median, indicator correlation scale becomes increasingly smaller for larger cutoffs of rainfall depth. A derived-distribution analysis, based on the assumption that radar rainfall is a linear sum of ground-truth and a random error, suggests that, at low cutoffs, indicator correlation scale of ground-truth can significantly differ from that of radar rainfall, and points toward inclusion of rainfall intermittency, for example, within the framework proposed in this work.
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  • 8
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    Stochastic environmental research and risk assessment 10 (1996), S. 151-161 
    ISSN: 1436-3259
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Energy, Environment Protection, Nuclear Power Engineering , Geography , Geosciences
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  • 9
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    Stochastic environmental research and risk assessment 10 (1996), S. 163-166 
    ISSN: 1436-3259
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Energy, Environment Protection, Nuclear Power Engineering , Geography , Geosciences
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  • 10
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    Stochastic environmental research and risk assessment 10 (1996), S. 187-207 
    ISSN: 1436-3259
    Keywords: log-Gumbel distribution ; flood frequency analysis ; quantile estimation ; confidence intervals
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Energy, Environment Protection, Nuclear Power Engineering , Geography , Geosciences
    Notes: Abstract The log-Gumbel distribution is one of the extreme value distributions which has been widely used in flood frequency analysis. This distribution has been examined in this paper regarding quantile estimation and confidence intervals of quantiles. Specific estimation algorithms based on the methods of moments (MOM), probability weighted moments (PWM) and maximum likelihood (ML) are presented. The applicability of the estimation procedures and comparison among the methods have been illustrated based on an application example considering the flood data of the St. Mary's River.
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  • 11
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    Stochastic environmental research and risk assessment 10 (1996), S. 167-186 
    ISSN: 1436-3259
    Keywords: Reservoir stochastic theory ; reliability ; mean ; variance ; indicator function ; storage bounds ; nonlinear programming ; simulation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Energy, Environment Protection, Nuclear Power Engineering , Geography , Geosciences
    Notes: Abstract A new formulation is presented for the analysis of reservoir systems synthesizing concepts from the traditional stochastic theory of reservoir storage, moments analysis and reliability programming. The analysis is based on the development of the first and second moments for the stochastic storage state variable. These expressions include terms for the failure probabilities (probabilities of spill or deficit) and consider the storage bounds explicitly. Using this analysis, expected values of the storage state, variances of storage, optimal release policies and failure probabilities — useful information in the context of reservoir operations and design, can be obtained from a nonlinear programming solution. The solutions developed from studies of single reservoir operations on both an annual and monthly basis, compare favorably with those obtained from simulation. The presentation herein is directed to both traditional reservoir storage theorists who are interested in the design of a reservoir and modern reservoir analysts who are interested in the long term operation of reservoirs.
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  • 12
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    Stochastic environmental research and risk assessment 10 (1996), S. 209-229 
    ISSN: 1436-3259
    Keywords: Infiltration-advance equation ; water spreading ; cellular automata ; irrigation ; surface hydrology ; hydrodynamics ; stochastic processes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Energy, Environment Protection, Nuclear Power Engineering , Geography , Geosciences
    Notes: Abstract A technique has been developed for predicting the irregular advance pattern often observed as water spreads on the surface of the ground. The technique is a combination of stochastic sketching, potential theory, probability theory, and a mass balance equation in the form of an advance equation. The technique can be used on flat as well as sloping terrain and addresses any form of obstructions or constraints to the flow of the water. The stochastic sketching portion of the technique uses cellular automata with transition probability movement rules to sketch the dynamics of small volume water elements in the defined environment. Randomly selected small volume flow path segments are computed and plotted. The envelope of these segments defines the wetted area and the advance front. Several examples are presented showing the patterns produced for various situations.
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  • 13
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    Stochastic environmental research and risk assessment 10 (1996), S. 231-251 
    ISSN: 1436-3259
    Keywords: Stochastic ; multiphase ; three phase ; heterogeneity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Energy, Environment Protection, Nuclear Power Engineering , Geography , Geosciences
    Notes: Abstract The first paper (Chang et al., 1995b) of this two-part series described the stochastic analysis using spectral/perturbation approach to analyze steady state two-phase (water and oil) flow in a, liquid-unsaturated, three fluid-phase porous medium. In this paper, the results between the numerical simulations and closed-form expressions obtained using the perturbation approach are compared. We present the solution to the one-dimensional, steady-state oil and water flow equations. The stochastic input processes are the spatially correlated logk where k is the intrinsic permeability and the soil retention parameter, α. These solutions are subsequently used in the numerical simulations to estimate the statistical properties of the key output processes. The comparison between the results of the perturbation analysis and numerical simulations showed a good agreement between the two methods over a wide range of logk variability with three different combinations of input stochastic processes of logk and soil parameter α. The results clearly demonstrated the importance of considering the spatial variability of key subsurface properties under a variety of physical scenarios. The variability of both capillary pressure and saturation is affected by the type of input stochastic process used to represent the spatial variability. The results also demonstrated the applicability of perturbation theory in predicting the system variability and defining effective fluid properties through the ergodic assumption.
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  • 14
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    Stochastic environmental research and risk assessment 10 (1996), S. 295-317 
    ISSN: 1436-3259
    Keywords: Bayesion methods ; time series ; hydrology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Energy, Environment Protection, Nuclear Power Engineering , Geography , Geosciences
    Notes: Abstract A review of literature reveals the inadequacy of Intervention analysis and spectrum based methods to adequately quantify changes in hydrologic times series. A Bayesian method is used to investigate the statistical significance of observed changes in hydrologic times series and the results are reported herein. The Bayesian method is superior to the previous methods.
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  • 15
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    Stochastic environmental research and risk assessment 10 (1996), S. 253-278 
    ISSN: 1436-3259
    Keywords: Random fields ; stochastic processes ; fractals
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Energy, Environment Protection, Nuclear Power Engineering , Geography , Geosciences
    Notes: Abstract This paper describes a new method for generating spatially-correlated random fields. Such fields are often encountered in hydrology and hydrogeology and in the earth sciences. The method is based on two observations: (i) spatially distributed attributes usually display a stationary correlation structure, and (ii) the screening effect of measurements leads to the sufficiency of a small search neighborhood when it comes to projecting measurements and data in space. The algorithm which was developed based on these principles is called HYDRO_GEN, and its features and properties are discussed in depth. HYDRO_GEN is found to be accurate and extremely fast. It is also versatile: it can simulate fields of different nature, starting from weakly stationary fields with a prescribed covariance and ending with fractal fields. The simulated fields can display statistical isotropy or anisotropy.
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  • 16
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    Stochastic environmental research and risk assessment 10 (1996), S. 279-294 
    ISSN: 1436-3259
    Keywords: Linear estimation ; interpolation ; kriging ; splines ; conditional
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Energy, Environment Protection, Nuclear Power Engineering , Geography , Geosciences
    Notes: Abstract This work presents analytical expressions for the best estimate, conditional covariance function, and conditional realizations of a function from sparse observations. In contrast to the prevalent approach in kriging where the best estimates at every point are determined from the solution of a system of linear equations, the best-estimate function can be represented analytically in terms of basis functions, whose number depends on the observations. This approach is computationally superior when graphing a function estimate and is also valuable in understanding what the solution should look like. For example, one can immediately see that all “singularities” in the best-estimate function are at observation points.
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  • 17
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    Stochastic environmental research and risk assessment 10 (1996), S. 319-329 
    ISSN: 1436-3259
    Keywords: Particle tracking ; numerical methods ; random walks ; advection-dispersion equation ; stochastic processes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Energy, Environment Protection, Nuclear Power Engineering , Geography , Geosciences
    Notes: Abstract A formal statistical discussion of the origins of the random walk and its relation to the classic advection-dispersion equation is given. At issue is the common use of Gaussian distributed steps in producing the desired dispersive effects. Shown are alternative solutions to the basic Langevin equation describing mass displacements based on non-Gaussian, white increments. In particular, the results reveal that uniform or symmetric-triangular steps can be employed without loss of generality in accuracy of the solution (over all Peclet numbers) and may yield significant savings in the computational generation of the random deviates required in the Monte Carlo procedures of the random walk method.
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  • 18
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    Stochastic environmental research and risk assessment 10 (1996), S. 330-330 
    ISSN: 1436-3259
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Energy, Environment Protection, Nuclear Power Engineering , Geography , Geosciences
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  • 19
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    Stochastic environmental research and risk assessment 11 (1997), S. 17-31 
    ISSN: 1436-3259
    Keywords: Bivariate density ; meta-Gaussian density ; normal quantile transform ; likelihood ratio dependence ; correlation coefficient
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Energy, Environment Protection, Nuclear Power Engineering , Geography , Geosciences
    Notes: Abstract Convenient bivariate densities found in the literature are often unsuitable for modeling hydrologic variates. They either constrain the range of association between variates, or fix the form of the marginal distributions. The bivariate meta-Gaussian density is constructed by embedding the normal quantile transform of each variate into the Gaussian law. The density can represent a full range of association between variates and admits arbitrarily specified marginal distributions. Modeling and estimation can be decomposed into i) independent analyses of the marginal distributions, and ii) investigation of the dependence structure. Both statistical and judgmental estimation procedures are possible. Some comparisons to recent applications of bivariate densities in the hydrologic literature motivate and illustrate the model.
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  • 20
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    Stochastic environmental research and risk assessment 11 (1997), S. 33-50 
    ISSN: 1436-3259
    Keywords: Unit hydrograph ; uncertainty analysis ; linearly constrained Monte-Carlo simulation ; reliability analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Energy, Environment Protection, Nuclear Power Engineering , Geography , Geosciences
    Notes: Abstract Unit hydrographs (UHs), along with design rainfalls, are frequently used to determine the discharge hydrograph for design and evaluation of hydraulic structures. Due to the presence of various uncertainties in its derivation, the resulting UH is inevitably subject to uncertainty. Consequently, the performance of hydraulic structures under the design storm condition is uncertain. This paper integrates the linearly constrained Monte-Carlo simulation with the UH theory and routing techniques to evaluate the reliability of hydraulic structures. The linear constraint is considered because the water volume of each generated design direct runoff hydrograph should be equal to that of the design effective rainfall hyetograph or the water volume of each generated UH must be equal to one inch (or cm) over the watershed. For illustration, the proposed methodology is applied to evaluate the overtopping risk of a hypothetical flood detention reservoir downstream of Tong-Tou watershed in Taiwan.
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  • 21
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    Stochastic environmental research and risk assessment 11 (1997), S. 1-16 
    ISSN: 1436-3259
    Keywords: Nash cascade reservoir model ; rainfall-runoff ; EM algorithm ; filtering ; maximum likelihood estimation ; martingale estimating function
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Energy, Environment Protection, Nuclear Power Engineering , Geography , Geosciences
    Notes: Abstract Abstract: Linear continuous time stochastic Nash cascade conceptual models for runoff are developed. The runoff is modeled as a simple system of linear stochastic differential equations driven by white Gaussian and marked point process noises. In the case of d reservoirs, the outputs of these reservoirs form a d dimensional vector Markov process, of which only the dth coordinate process is observed, usually at a discrete sample of time points. The dth coordinate process is not Markovian. Thus runoff is a partially observed Markov process if it is modeled using the stochastic Nash cascade model. We consider how to estimate the parameters in such models. In principle, maximum likelihood estimation for the complete process parameters can be carried out directly or through some form of the EM (estimation and maximization) algorithm or variation thereof, applied to the observed process data. In this research we consider a direct approximate likelihood approach and a filtering approach to an algorithm of EM type, as developed in Thompson and Kaseke (1994). These two methods are applied to some real life runoff data from a catchment in Wales, England. We also consider a special case of the martingale estimating function approach on the runoff model in the presence of rainfall. Finally, some simulations of the runoff process are given based on the estimated parameters.
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  • 22
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    Stochastic environmental research and risk assessment 11 (1997), S. 173-192 
    ISSN: 1436-3259
    Keywords: Uncertainty analysis ; unit hydrograph ; regression analysis ; probabilistic point estimation methods
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Energy, Environment Protection, Nuclear Power Engineering , Geography , Geosciences
    Notes: Abstract Hydrologic model parameters obtained from regional regression equations are subject to uncertainty. Consequently, hydrologic model outputs based on the stochastic parameters are random. This paper presents a systematic analysis of uncertainty associated with the two parameters, N and K, in Nash's IUH model from different regional regression equations. The uncertainty features associated with N and K are further incorporated to assess the uncertainty of the resulting IUH. Numerical results indicate that uncertainty of N and K from the regional regression equations are too significant to be ignored.
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  • 23
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    Stochastic environmental research and risk assessment 11 (1997), S. 145-171 
    ISSN: 1436-3259
    Keywords: Hydrologic regionalization ; unit hydrograph ; regression analysis ; multivariate regression ; seemingly unrelated regression ; validation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Energy, Environment Protection, Nuclear Power Engineering , Geography , Geosciences
    Notes: Abstract Hydrologic regionalization is a useful tool that allows for the transfer of hydrological information from gaged sites to ungaged sites. This study developed regional regression equations that relate the two parameters in Nash's IUH model to the basin characteristics for 42 major watersheds in Taiwan. In the process of developing the regional equations, different regression procedures including the conventional univariate regression, multivariate regression, and seemingly unrelated regression were used. Multivariate regression and seeming unrelated regression were applied because there exists a rather strong correlation between the Nash's IUH parameters. Furthermore, a validation study was conducted to examine the predictability of regional equations derived by different regression procedures. The study indicates that hydrologic regionalization involving several dependent variables should consider their correlations in the process of establishing the regional equations. The consideration of such correlation will enhance the predictability of resulting regional equations as compared with the ones from the conventional univariate regression procedure.
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  • 24
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    Stochastic environmental research and risk assessment 11 (1997), S. 193-210 
    ISSN: 1436-3259
    Keywords: Turbulence ; sediment ; fluvial ; river ; bursting process ; statistics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Energy, Environment Protection, Nuclear Power Engineering , Geography , Geosciences
    Notes: Abstract Entrainment of sediment particles from channel beds into the channel flow is influenced by the characteristics of the flow turbulence which produces stochastic shear stress fluctuations at the bed. Recent studies of the structure of turbulent flow has recognized the importance of bursting processes as important mechanisms for the transfer of momentum into the laminar boundary layer. Of these processes, the sweep event has been recognized as the most important bursting event for entrainment of sediment particles as it imposes forces in the direction of the flow resulting in movement of particles by rolling, sliding and occasionally saltating. Similarly, the ejection event has been recognized as important for sediment transport since these events maintain the sediment particles in suspension. In this study, the characteristics of bursting processes and, in particular, the sweep event were investigated in a flume with a rough bed. The instantaneous velocity fluctuations of the flow were measured in two-dimensions using a small electromagnetic velocity meter and the turbulent shear stresses were determined from these velocity fluctuations. It was found that the shear stress applied to the sediment particles on the bed resulting from sweep events depends on the magnitude of the turbulent shear stress and its probability distribution. A statistical analysis of the experimental data was undertaken and it was found necessary to apply a Box-Cox transformation to transform the data into a normally distributed sample. This enabled determination of the mean shear stress, angle of action and standard error of estimate for sweep and ejection events. These instantaneous shear stresses were found to be greater than the mean flow shear stress and for the sweep event to be approximately 40 percent greater near the channel bed. Results from this analysis suggest that the critical shear stress determined from Shield's diagram is not sufficient to predict the initiation of motion due to its use of the temporal mean shear stress. It is suggested that initiation of particle motion, but not continuous motion, can occur earlier than suggested by Shield's diagram due to the higher shear stresses imposed on the particles by the stochastic shear stresses resulting from turbulence within the flow.
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  • 25
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    Stochastic environmental research and risk assessment 11 (1997), S. 211-227 
    ISSN: 1436-3259
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Energy, Environment Protection, Nuclear Power Engineering , Geography , Geosciences
    Notes: Abstract The principle of maximum entropy (POME) was employed to derive a new method of parameter estimation for the 2-parameter generalized Pareto (GP2) distribution. Monte Carlo simulated data were used to evaluate this method and compare it with the methods of moments (MOM), probability weighted moments (PWM), and maximum likelihood estimation (MLE). The parameter estimates yielded by POME were comparable or better within certain ranges of sample size and coefficient of variation.
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  • 26
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    Stochastic environmental research and risk assessment 11 (1997), S. 523-547 
    ISSN: 1436-3259
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Energy, Environment Protection, Nuclear Power Engineering , Geography , Geosciences
    Notes: Abstract Kernel density estimators are useful building blocks for empirical statistical modeling of precipitation and other hydroclimatic variables. Data driven estimates of the marginal probability density function of these variables (which may have discrete or continuous arguments) provide a useful basis for Monte Carlo resampling and are also useful for posing and testing hypotheses (e.g bimodality) as to the frequency distributions of the variable. In this paper, some issues related to the selection and design of univariate kernel density estimators are reviewed. Some strategies for bandwidth and kernel selection are discussed in an applied context and recommendations for parameter selection are offered. This paper complements the nonparametric wet/dry spell resampling methodology presented in Lall et al. (1996).
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  • 27
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    Stochastic environmental research and risk assessment 11 (1997), S. 459-482 
    ISSN: 1436-3259
    Keywords: Karhunen-Loéve expansion ; Empirical Orthogonal Functions ; stochastic simulation ; gaussian fields ; analytical covariance functions ; eigenfunctions ; kriging
    Source: Springer Online Journal Archives 1860-2000
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    Notes: Abstract Simulation of multigaussian stochastic fields can be made after a Karhunen-Loéve expansion of a given covariance function. This method is also called simulation by Empirical Orthogonal Functions. The simulations are made by drawing stochastic coefficients from a random generator. These numbers are multiplied with eigenfunctions and eigenvalues derived from the predefined covariance model. The number of eigenfunctions necessary to reproduce the stochastic process within a predefined variance error, turns out to be a cardinal question. Some ordinary analytical covariance functions are used to evaluate how quickly the series of eigenfunctions can be truncated. This analysis demonstrates extremely quick convergence to 99.5% of total variance for the 2nd order exponential (‘gaussian’) covariance function, while the opposite is true for the 1st order exponential covariance function. Due to these convergence characteristics, the Karhunen-Loéve method is most suitable for simulating smooth fields with ‘gaussian’ shaped covariance functions. Practical applications of Karhunen-Loéve simulations can be improved by spatial interpolation of the eigenfunctions. In this paper, we suggest interpolation by kriging and limits for reproduction of the predefined covariance functions are evaluated.
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    Stochastic environmental research and risk assessment 12 (1998), S. 1-14 
    ISSN: 1436-3259
    Keywords: Key words: Exceedance probability ; trend ; stochastic variables ; non-stationarity
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    Notes: Abstract Studying the hypothetical case of a trend superimposed on a random stationary variable, we highlight the strong influence of possible non-stationarities on exceedance probability. After a general outline, the subject is analytically developed using the Gumbel distribution, emphasizing the quick increase of the exceedance probability over time in the presence of weak rising trends, and its sensitive underestimation where the non-stationarity goes unnoticed or is considered negligible. Finally the work is applied to hydrological series of rainfall and river flow.
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    Stochastic environmental research and risk assessment 12 (1998), S. 53-64 
    ISSN: 1436-3259
    Keywords: Key words: Risk ; clustering ; point process ; Poisson ; flood.
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    Topics: Architecture, Civil Engineering, Surveying , Energy, Environment Protection, Nuclear Power Engineering , Geography , Geosciences
    Notes: Abstract: Since the introduction into flood risk analysis, the partial duration series method has gained increasing acceptance as an appealing alternative to the annual maximum series method. However, when the base flow is low, there is clustering in the flood peak or flow volume point process. In this case, the general stochastic point process model is not suitable to risk analysis. Therefore, two types of models for flood risk analysis are derived on the basis of clustering stochastic point process theory in this paper. The most remarkable characteristic of these models is that the flood risk is considered directly within the time domain. The acceptability of different models are also discussed with the combination of the flood peak counted process in twenty years at Yichang station on the Yangtze river. The result shows that the two kinds of models are suitable ones for flood risk analysis, which are more flexible compared with the traditional flood risk models derived on the basis of annual maximum series method or the general stochastic point process theory.
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    Stochastic environmental research and risk assessment 12 (1998), S. 33-52 
    ISSN: 1436-3259
    Keywords: Keywords: Streamflow ; simulation ; nonparametric
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    Notes: Abstract A new approach for streamflow simulation using nonparametric methods was described in a recent publication (Sharma et al. 1997). Use of nonparametric methods has the advantage that they avoid the issue of selecting a probability distribution and can represent nonlinear features, such as asymmetry and bimodality that hitherto were difficult to represent, in the probability structure of hydrologic variables such as streamflow and precipitation. The nonparametric method used was kernel density estimation, which requires the selection of bandwidth (smoothing) parameters. This study documents some of the tests that were conduced to evaluate the performance of bandwidth estimation methods for kernel density estimation. Issues related to selection of optimal smoothing parameters for kernel density estimation with small samples (200 or fewer data points) are examined. Both reference to a Gaussian density and data based specifications are applied to estimate bandwidths for samples from bivariate normal mixture densities. The three data based methods studied are Maximum Likelihood Cross Validation (MLCV), Least Square Cross Validation (LSCV) and Biased Cross Validation (BCV2). Modifications for estimating optimal local bandwidths using MLCV and LSCV are also examined. We found that the use of local bandwidths does not necessarily improve the density estimate with small samples. Of the global bandwidth estimators compared, we found that MLCV and LSCV are better because they show lower variability and higher accuracy while Biased Cross Validation suffers from multiple optimal bandwidths for samples from strongly bimodal densities. These results, of particular interest in stochastic hydrology where small samples are common, may have importance in other applications of nonparametric density estimation methods with similar sample sizes and distribution shapes.
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    Stochastic environmental research and risk assessment 12 (1998), S. 15-32 
    ISSN: 1436-3259
    Keywords: Key words: Kalman filtering ; groundwater modelling ; inverse methods ; uncertainty analysis ; state prediction ; parameter estimation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Energy, Environment Protection, Nuclear Power Engineering , Geography , Geosciences
    Notes: Abstract The popularity of applying filtering theory in the environmental and hydrological sciences passed its first climax in the 1970s. Like so many other new mathematical methods it was simply the fashion at the time. The study of groundwater systems was not immune to this fashion, but neither was it by any means a prominent area of application. The spatial-temporal characteristics of groundwater flow are customarily described by analytical or, more frequently, numerical, physics-based models. Consequently, the state-space representations associated with filtering must be of a high order, with an immediately apparent computational over-burden. And therein lies part of the reason for the but modest interest there has been in applying Kalman filtering to groundwater systems, as reviewed critically in this paper. Filtering theory may be used to address a variety of problems, such as: state estimation and reconstruction, parameter estimation (including the study of uncertainty and its propagation), combined state-parameter estimation, input estimation, estimation of the variance-covariance properties of stochastic disturbances, the design of observation networks, and the analysis of parameter identifiability. A large proportion of previous studies has dealt with the problem of parameter estimation in one form or another. This may well not remain the focus of attention in the future. Instead, filtering theory may find wider application in the context of data assimilation, that is, in reconstructing fields of flow and the migration of sub-surface contaminant plumes from relatively sparse observations.
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    Stochastic environmental research and risk assessment 12 (1998), S. 65-82 
    ISSN: 1436-3259
    Keywords: Key words: Flood flow ; threshold ; generalized Pareto ; Poisson
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    Topics: Architecture, Civil Engineering, Surveying , Energy, Environment Protection, Nuclear Power Engineering , Geography , Geosciences
    Notes: Abstract This study uses the method of peaks over threshold (P.O.T.) to estimate the flood flow quantiles for a number of hydrometric stations in the province of New Brunswick, Canada. The peak values exceeding the base level (threshold), or `exceedances', are fitted by a generalized Pareto distribution. It is known that under the assumption of Poisson process arrival for flood exceedances, the P.O.T. model leads to a generalized extreme value distribution (GEV) for yearly maximum discharge values. The P.O.T. model can then be applied to calculate the quantiles X T corresponding to different return periods T, in years. A regionalization of floods in New Brunswick, which consists of dividing the province into `homogeneous regions', is performed using the method of the `region of influence'. The 100-year flood is subsequently estimated using a regionally estimated value of the shape parameter of the generalized Pareto distribution and a regression of the 100-year flood on the drainage area. The jackknife sampling method is then used to contrast the regional results with the values estimated at site. The variability of these results is presented in box-plot form.
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    Stochastic environmental research and risk assessment 12 (1998), S. 97-116 
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    Notes: Abstract : The knowledge of the volume and duration of low-flow events in river channels is essential for water management and the design of hydraulics structures. In this study, both preceding characteristics, X 1 and X 2, are considered simultaneously via two types of bivariate distributions whose marginals are exponential. One of these bivariate distributions has been presented by Nagao and Kadoya (1971) and the other has been used by Singh and Singh (1991) to the study of rainfall intensity and rainfall depth. The results are applied to the low-flow series (“peaks-below-threshold”) of Lepreau River (station 01AQ001) in New Brunswick, Canada. These results show that the model that was successfully employed by Singh and Singh (1991) to study rainfall, presents certain difficulties when a very strong correlation, ρ, between the two random variables X 1 and X 2, exists. The model by Nagao and Kadoya (1971) seems to be more satisfactory for such situations, although this model seems also to be quite sensitive to variations in ρ.
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    Stochastic environmental research and risk assessment 12 (1998), S. 83-96 
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    Notes: Abstract Many natural porous geological rock formations, as well as engineered porous structures, have fractal properties, i.e., they are self-similar over several length scales. While there have been many experimental and theoretical studies on how to quantify a fractal porous medium and on how to determine its fractal dimension, the numerical generation of a fractal pore structure with predefined statistical and scaling properties is somewhat scarcer. In the present paper a new numerical method for generating a three-dimensional porous medium with any desired probability density function (PDF) and autocorrelation function (ACF) is presented. The well-known Turning Bands Method (TBM) is modified to generate three-dimensional synthetic isotropic and anisotropic porous media with a Gaussian PDF and exponential-decay ACF. Porous media with other PDF's and ACF's are constructed with a nonlinear, iterative PDF and ACF transformation, whereby the arbitrary PDF is converted to an equivalent Gaussian PDF which is then simulated with the classical TBM. Employing a new method for the estimation of the surface area for a given porosity, the fractal dimensions of the surface area of the synthetic porous media generated in this way are then measured by classical fractal perimeter/area relationships. Different 3D porous media are simulated by varying the porosity and the correlation structure of the random field. The performance of the simulations is evaluated by checking the ensemble statistics, the mean, variance and ACF of the simulated random field. For a porous medium with Gaussian PDF, an average fractal dimension of approximately 2.76 is obtained which is in the range of values of actually measured fractal dimensions of molecular surfaces. For a porous medium with a non-Gaussian quadratic PDF the calculated fractal dimension appears to be consistently higher and averages 2.82. The results also show that the fractal dimension is neither strongly dependent of the porosity nor of the degree of anisotropy assumed.
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    Stochastic environmental research and risk assessment 12 (1998), S. 117-140 
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    Notes: Abstract Transport of non-ergodic solute plumes by steady-state groundwater flow with a uniform mean velocity, μ, were simulated with Monte Carlo approach in a two-dimensional heterogeneous and statistically isotropic aquifer whose transmissivity, T, is log-normally distributed with an exponential covariance. The ensemble averages of the second spatial moments of the plume about its center of mass, 〈S i i (t)〉, and the plume centroid covariance, R i i (t) (i=1,2), were simulated for the variance of Y=log T, σ Y 2=0.1, 0.5 and 1.0 and line sources normal or parallel to μ of three dimensionless lengths, 1, 5, and 10. For σ Y 2=0.1, all simulated 〈S i i (t)〉−S i i (0) and R i i (t) agree well with the first-order theoretical values, where S i i (0) are the initial values of S i i (t). For σ Y 2=0.5 and 1.0 and the line sources normal to μ, the simulated longitudinal moments, 〈S 11(t)〉−S 11(0) and R 11(t), agree well with the first-order theoretical results but the simulated transverse moments 〈S 22(t)〉−S 22(0) and R 22(t) are significantly larger than the first-order values. For the same two larger values of σ Y 2 but the line sources parallel to μ, the simulated 〈S 11(t)〉−S 11(0) are larger than but the simulated R 11 are smaller than the first-order values, and both simulated 〈S 22(t)〉−S 22(0) and R 22(t) stay larger than the first-order values. For a fixed value of σ Y 2, the summations of 〈S i i (t)〉−S i i (0) and R i i , i.e., X i i (i=1,2), remain almost the same no matter what kind of source simulated. The simulated X 11 are in good agreement with the first-order theory but the simulated X 22 are significantly larger than the first-order values. The simulated X 22, however, are in excellent agreement with a previous modeling result and both of them are very close to the values derived using Corrsin's conjecture. It is found that the transverse moments may be significantly underestimated if less accurate hydraulic head solutions are used and that the decreasing of 〈S 22(t)〉−S 22(0) with time or a negative effective dispersivity, defined as , may happen in the case of a line source parallel to μ where σ Y 2 is small.
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    Stochastic environmental research and risk assessment 12 (1998), S. 141-154 
    ISSN: 1436-3259
    Keywords: Key words: Ground truth ; geostatistical techniques ; areal reduction factor ; Rainfall process ; linear relationship.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Energy, Environment Protection, Nuclear Power Engineering , Geography , Geosciences
    Notes: Abstract Geostatistical techniques are used to quantify the reference mean areal rainfall (ground truth) from sparse raingaugenetworks. Based on the EPSAT-Niger event cumulative rainfall, a linear relationship between the ground truth considered as the mean area rainfall estimated from the densely available raingauge network and the area rainfall estimated from sparse network are derived. Also, a linear relationship between the ground truth and point rainfall is established. As it was reported experimentally by some authors, the slope of these relationships is less than one. Based on the geostatistical framework, the slope and the ordinate at the origin can be estimated as a function of the spatial structure of the rainfall process. It is shown that the slope is smaller than one. For the special case of one gauge inside a fixed area or a Field Of View (FOV), an areal reduction factor is derived. It has a limit value which depends only on the size of the area and the spatial structure of the rainfall process. The relative variance error of estimating the FOV cumulative rainfall from point rainfall is also given.
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    Stochastic environmental research and risk assessment 12 (1998), S. 223-245 
    ISSN: 1436-3259
    Keywords: Key words: Stochastic differential equation ; spatial data ; irregularly sampled data ; parameter estimation.
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    Notes: Abstract: A second order stochastic differential equation is used for modeling of water-table elevation. The data were sampled at the Borden Aquifer as a part of a tracer experiment. The purpose of the water-table data collection was to determine presence of a water flow. We argue that the water-table surface is a simple plane oscillating up and down in time according to an equation for a stochastic oscillator. We derive the model, estimate its parameters and provide arguments for goodness-of-fit of the model.
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    Stochastic environmental research and risk assessment 12 (1998), S. 267-283 
    ISSN: 1436-3259
    Keywords: Key words: Flood frequency analysis ; TCEV ; non-systematic information ; regional ; statistical gain.
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    Topics: Architecture, Civil Engineering, Surveying , Energy, Environment Protection, Nuclear Power Engineering , Geography , Geosciences
    Notes: Abstract: Due to the social and economic implications, flood frequency analysis must be done with the highest precision. For this reason, the most suitable statistical model must be selected, and the maximum amount of information must be used. Floods in Mediterranean rivers can be produced by two different mechanisms, which forces the use of a non-traditional distribution like the TCEV. The information can be increased by using additional non-systematic data, or with a regional analysis, or both. Through the statistical gain concept, it has been shown that in most cases the use of additional non-systematic information can decrease the quantile estimation error in about 50%. In a regional analysis, the␣benefit of additional information in one station, is propagated to the rest of␣the␣stations with only a small decrease with respect to the at-site equivalent analysis.
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    Stochastic environmental research and risk assessment 12 (1998), S. 285-298 
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    Notes: Abstract We present a geostatistically based inverse model for characterizing heterogeneity in parameters of unsaturated hydraulic conductivity for three-dimensional flow. Pressure and moisture content are related to perturbations in hydraulic parameters through cross-covariances, which are calculated to first-order. Sensitivities needed for covariance calculations are derived using the adjoint state sensitivity method. Approximations of the conditional mean parameter fields are then obtained from the cokriging estimator. Correlation between parameters and pressure – moisture content perturbations is seen to be strongly dependent on mean pressure or moisture content. High correlation between parameters and pressure data was obtained under saturated or near saturated flow conditions, providing accurate estimation of saturated hydraulic conductivity, while moisture content measurements provided accurate estimation of the pore size distribution parameter under unsaturated flow conditions.
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    Stochastic environmental research and risk assessment 12 (1998), S. 247-266 
    ISSN: 1436-3259
    Keywords: Key words: Stochastic control ; dynamic programming ; reservoir systems ; hydrologic forecasting ; hydropower ; feedback control ; autoregressive models.
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    Notes: Abstract : As with all dynamic programming formulations, differential dynamic programming (DDP) successfully exploits the sequential decision structure of multi-reservoir optimization problems, overcomes difficulties with the nonconvexity of energy production functions for hydropower systems, and provides optimal feedback release policies. DDP is particularly well suited to optimizing large-scale multi-reservoir systems due to its relative insensitivity to state-space dimensionality. This advantage of DDP encourages expansion of the state vector to include additional multi-lag hydrologic information and/or future inflow forecasts in developing optimal reservoir release policies. Unfortunately, attempts at extending DDP to the stochastic case have not been entirely successful. A modified stochastic DDP algorithm is presented which overcomes difficulties in previous formulations. Application of the algorithm to a four-reservoir hydropower system demonstrates its capabilities as an efficient approach to solving stochastic multi-reservoir optimization problems. The algorithm is also applied to a single reservoir problem with inclusion of multi-lag hydrologic information in the state vector. Results provide evidence of significant benefits in direct inclusion of expanded hydrologic state information in optimal feedback release policies.
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    Stochastic environmental research and risk assessment 12 (1998), S. 299-316 
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    Notes: Abstract This paper presents a geostatistical approach to multi-directional aquifer stimulation in order to better identify the transmissivity field. Hydraulic head measurements, taken at a few locations but under a number of different steady-state flow conditions, are used to estimate the transmissivity. Well installation is generally the most costly aspect of obtaining hydraulic head measurements. Therefore, it is advantageous to obtain as many informative measurements from each sampling location as possible. This can be achieved by hydraulically stimulating the aquifer through pumping, in order to set-up a variety of flow conditions. We illustrate the method by applying it to a synthetic aquifer. The simulations provide evidence that a few sampling locations may provide enough information to estimate the transmissivity field. Furthermore, the innovation of, or new information provided by, each measurement can be examined by looking at the corresponding spline and sensitivity matrix. Estimates from multi-directional stimulation are found to be clearly superior to estimates using data taken under one flow condition. We describe the geostatistical methodology for using data from multi-directional simulations and address computational issues.
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    Stochastic environmental research and risk assessment 9 (1995), S. 33-47 
    ISSN: 1436-3259
    Keywords: Hidden markov models ; maximum likelihood estimation ; EM algorithm ; martingale estimating function ; forward-backward algorithm ; Monte Carlo ; filtering ; Nash cascade model ; rainfall runoff modeling
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    Topics: Architecture, Civil Engineering, Surveying , Energy, Environment Protection, Nuclear Power Engineering , Geography , Geosciences
    Notes: Abstract Many stochastic process models for environmental data sets assume a process of relatively simple structure which is in some sense partially observed. That is, there is an underlying process (Xn, n ≥ 0) or (Xt, t ≥ 0) for which the parameters are of interest and physically meaningful, and an observable process (Yn, n ≥ 0) or (Yt, t ≥ 0) which depends on the X process but not otherwise on those parameters. Examples are wide ranging: the Y process may be the X process with missing observations; the Y process may be the X process observed with a noise component; the X process might constitute a random environment for the Y process, as with hidden Markov models; the Y process might be a lower dimensional function or reduction of the X process. In principle, maximum likelihood estimation for the X process parameters can be carried out by some form of the EM algorithm applied to the Y process data. In the paper we review some current methods for exact and approximate maximum likelihood estimation. We illustrate some of the issues by considering how to estimate the parameters of a stochastic Nash cascade model for runoff. In the case of k reservoirs, the outputs of these reservoirs form a k dimensional vector Markov process, of which only the kth coordinate process is observed, usually at a discrete sample of time points.
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    Stochastic environmental research and risk assessment 9 (1995), S. 117-132 
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    Keywords: River Quality ; network ; computer model ; Thermodynamics
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    Topics: Architecture, Civil Engineering, Surveying , Energy, Environment Protection, Nuclear Power Engineering , Geography , Geosciences
    Notes: Abstract In this paper, concepts of network thermodynamics are applied to a river water quality model, which is based on Streeter-Phelps equations, to identify the corresponding physical components and their topology. Then, the randomness in the parameters, input coefficients and initial conditions are modeled by Gaussian white noises. From the stochastic components of the physical system description of problem and concepts of physical system theory, a set of stochastic differential equations can be automatically generated in a computer and the recent developments on the automatic formulation of the moment equations based on Ito calculus can be used. This procedure is illustrated through the solution of an example of stochastic river water quality problem and it is also shown how other related problems with different configurations can be automatically solved in a computer using just one software.
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    Stochastic environmental research and risk assessment 9 (1995), S. 171-205 
    ISSN: 1436-3259
    Keywords: AR-AIC-Bayes filter ; autoregressive spectral density estimation ; diagnostic checks for ARMA models ; exploratory data analysis ; fast Fourier transform ; Hurst coefficient ; long-memory times series ; periodogram smoothing ; riverflow time series ; spectral density plots
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Energy, Environment Protection, Nuclear Power Engineering , Geography , Geosciences
    Notes: Abstract Current methods of estimation of the univariate spectral density are reviewed and some improvements are made. It is suggested that spectral analysis may perhaps be best thought of as another exploratory data analysis (EDA) tool which complements, rather than competes with, the popular ARMA model building approach. A new diagnostic check for ARMA model adequacy based on the nonparametric spectral density is introduced. Additionally, two new algorithms for fast computation of the autoregressive spectral density function are presented. For improving interpretation of results, a new style of plotting the spectral density function is suggested. Exploratory spectral analyses of a number of hydrological time series are performed and some interesting periodicities are suggested for further investigation. The application of spectral analysis to determine the possible existence of long memory in natural time series is discussed with respect to long riverflow, treering and mud varve series. Moreover, a comparison of the estimated spectral densities suggests the ARMA models fitted previously to these datasets adequately describe the low frequency component. Finally, the software and data used in this paper are available by anonymous ftp from fisher.stats.uwo.ca.
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    Stochastic environmental research and risk assessment 9 (1995), S. 215-237 
    ISSN: 1436-3259
    Keywords: Computation ; discretization ; entropy ; networks ; time averaging ; water quality
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    Topics: Architecture, Civil Engineering, Surveying , Energy, Environment Protection, Nuclear Power Engineering , Geography , Geosciences
    Notes: Abstract The computational aspects of using a new, entropy-based, theory to predict water quality values at discontinued water quality monitoring stations are discussed. The main computational issues addressed are the level of discretization used in converting the continuous probability distribution of water quality values to the discrete levels required for the entropy function, and the choice of the interval of time for which to assign the value of the water quality (period of time averaging) through the entropy function. Unlike most cases of entropy applications involving discretization of continuous functions the results of using entropy theory to predict water quality values at discontinued monitoring stations in this application appear to be insensitive to the choice of the level of discretization even down to the very coarse level discretization associated with only eight intervals. However, depending on the length of record available the choice of the time interval for which the water quality values are assigned (period for time averaging) appear to have a significant impact on the accuracy of the results.
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    Stochastic environmental research and risk assessment 9 (1995), S. 13-32 
    ISSN: 1436-3259
    Keywords: Distributed parameter filter ; shallow water equations ; distributed dynamical systems ; data assimilation ; white Gaussian noise
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Energy, Environment Protection, Nuclear Power Engineering , Geography , Geosciences
    Notes: Abstract Distributed parameter filtering theory is employed for estimating the state variables and associated error covariances of a dynamical distributed system under highly random tidal and meteorological influences. The stochastic-deterministic mathematical model of the physical system under study consists of the shallow water equations described by the momentum and continuity equations in which the external forces such as Coriolis force, wind friction, and atmospheric pressure are considered. White Gaussian noises in the system and measurement equations are used to account for the inherent stochasticity of the system. By using an optimal distributed parameter filter, the information provided by the stochastic dynamical model and the noisy measurements taken from the actual system are combined to obtain an optimal estimate of the state of the system, which in turn is used as the initial condition for the prediction procedure. The approach followed here has numerical approximation carried out at the end, which means that the numerical discretization is performed in the filtering equations, and not in the equations modelling the system. Therefore, the continuous distributed nature of the original system is maintained as long as possible and the propagation of modelling errors in the problem is minimized. The appropriateness of the distributed parameter filter is demonstrated in an application involving the prediction of storm surges in the North Sea. The results confirm excellent filter performance with considerable improvement with respect to the deterministic prediction.
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    Stochastic environmental research and risk assessment 9 (1995), S. 77-88 
    ISSN: 1436-3259
    Keywords: Extreme rainfalls ; partial duration series ; regional estimation ; Bayes' theory
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Energy, Environment Protection, Nuclear Power Engineering , Geography , Geosciences
    Notes: Abstract Based on the Partial Duration Series model a regional Bayesian approach is introduced in the modelling of extreme rainfalls from a country-wide system of recording raingauges in Denmark. The application of the Bayesian principles is derived in case of both exponential and generalized Pareto-distributed exceedances. The method is applied to, respectively, the total precipitation depth and the maximum 10 minutes rain intensity of individual storms from 41 stations. By means of the regional analysis prior distributions of the parameters in the Partial Duration Series model are estimated. It is shown that the regional approach significantly reduces the uncertainty of the T-year event estimator compared to estimation based solely on at-site data. In addition, the regional approach provides quantile estimates at non-monitored sites.
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    ISSN: 1436-6215
    Keywords: Kraftsportler ; hohe Proteinzufuhr ; renale Nettosäureausscheidung ; Urin pH ; Ammoniumausscheidung ; Ammoniumproduktion ; renale Säureausscheidungskapazität ; Sulfat ; Bodybuilder ; high protein diet ; renal net acid excretion ; urine-pH ; ammonium excretion ; ammonia production ; sulfate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
    Description / Table of Contents: Summary Bodybuilders often prefer a high protein diet to achieve maximum skeletal muscle hypertrophy. In this study the effect of a high protein diet on renal acid load and renal handling of proton excretion was studied comparing dietary intake and urinary ionograms in 37 male bodybuilders and 20 young male adults. Energy intake (+7 %), protein intake (128 vs 88 g/d/1.73 m2), and renal net acid excretion (95 vs 64 mmol/d/1.73 m2) were higher in the bodybuilders than in the controls, however, urine-pH was only slightly lower (5.83 vs 6.12). In the bodybuilders renal ammonium excretion was higher at any given value of urine pH than in the controls. In a regression analysis protein intake proved to be an independent factor modulating the ratio between urine-pH and renal ammonium excretion. The concomitant increase of renal net acid excretion and maximum renal acid excretion capacity in periods of high protein intake appears to be a highly effective response of the kidney to a specific food intake leaving a large renal surplus capacity for an additional renal acid load.
    Notes: Zusammenfassung Kraftsportler ernähren sich zur Förderung des Muskelwachstums häufig proteinreich. In dieser Studie wurde die Wirkung einer hohen Proteinzufuhr auf die renale Säurelast und die renale Säureausscheidungskapazität anhand des Vergleichs der Daten der Nährstoffzufuhr und der Harnionogramme von 37 Kraftsportlern mit hoher Proteinzufuhr und 20 jungen Erwachsenen mit normaler Proteinzufuhr (Vergleichsgruppe) untersucht. Die Kraftsportler zeigten eine höhere Energie-(+7 %) und Proteinzufuhr (128 vs 88 g/d/1.73 m2) und eine höhere renale Nettosäureausscheidung (95 vs 64 mmol/d/1.73 m2) als die Vergleichsgruppe. Die Differenz der Urin pH-Werte der beiden Gruppen war allerdings erstaunlich gering (5.83 vs 6.12). Bei den Kraftsportlern war die renale Ammoniumausscheidung bei allen Urin pH-Werten deutlich höher als bei der Vergleichsgruppe. Eine Regressions-analyse ergab, daß die Proteinzufuhr das Verhältnis von Urin pH und renaler Ammoniumausscheidung eigenständig zu beeinflussen vermag. Eine vermehrte Proteinzufuhr führt zu einer erhöhten renalen Säurelast und Nettosäureausscheidung. Die gleichzeitig auftretende Steigerung der renalen Säureausscheidungskapazität infolge einer erhöhten Ammoniumproduktion stellt einen sinnvollen Anpassungsmechanismus des Körpers an diese besondere Form der Ernährung dar, der dem Körper eine ausreichende funktionelle Reservekapazität für weitere den Säure-Basen-Haushalt belastende pathophysiologische Ereignisse erhält.
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  • 49
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    European journal of nutrition 34 (1995), S. 160-163 
    ISSN: 1436-6215
    Keywords: Immunglobulin G ; Dotterantikörper ; Intestinale Absorption ; Kalb ; Immunoglobulin G ; yolk antibodies ; intestinal absorption ; calf
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
    Description / Table of Contents: Summary Studying the prophylactic effects of specific yolk antibodies against diarrhea in newborn calves, also the intestinal absorption of unspecific heterogeneous avian antibodies as well as their effects on the uptake of maternal bovine colostral antibodies (bIgG) was investigated. Two groups of newborn calves received egg powder (16 g or 8 g per day) for the first 10 days of their life beginning with the first meal. A third group was kept as a control without any egg powder in their diet. Blood samples (5 to 10 calves per sampling time) were taken from 123 calves at 6, 12, 24, 48, or 96 h postnatally. With both doses the highest chicken IgG (cIgG) levels (3.1 µg resp. 1.2 µg per ml serum) have been measured 12 h after birth. These concentrations decreased continuously to the levels of 1.1 µg resp. 0.2 µg cIgG per ml serum at 96 h postnatally. The uptake into blood at 6 h postnatally has roughly been estimated as approximately 23 % (bIgG) and 7 % resp. 6 % (cIgG) of the IgG dosages given with the first meal. The time-course (6 to 96 h) of the bIgG level in blood was quite stable, plateauing already after 6 h at a mean of 5.9 mg per ml serum. Significant differences between the bIgG levels of calves with yolk antibodies in their diet (6.2 resp. 6.1 mg bIgG per ml serum) and those of the control group (5.4 mg per ml serum) could not be observed. Obviously, the prophylactic use of egg powder in newborn calves has no negative effect on the absorption of colostral antibodies. However, with the feeding of chicken egg yolk antibodies already with the first meal also the absorption of avian antibodies has to be taken into consideration.
    Notes: Zusammenfassung Im Rahmen einer Untersuchung zur prophylaktischen Wirksamkeit von spezifischen Dotterantikörpern bei erregerbedingten Kälberdurchfällen wurde auch die Absorption der unspezifischen heterologen aviären Dotterantikörper (cIgG) und deren Wirkung auf die Aufnahme von maternalen bovinen Kolostrumantikörpern (bIgG) überprüft. Zwei Gruppen von neugeborenen Kälbern wurde sprühgetrocknetes Volleipulver ab der ersten Tränke in einer Dosierung entweder von 16 g oder von 8 g pro Tag während der ersten 10 Lebenstage verabreicht. Eine dritte Gruppe diente als Kontrolle und erhielt kein Eipulver. Von insgesamt 123 Kälbern (5 bis 10 Kälber pro Entnahmezeitpunkt) wurden 6, 12, 24, 48, 72 bzw. 96 Stunden post natum Blutproben genommen. Bei beiden Eipulverdosierungen wurden die höchsten Hühner-IgG-Konzentrationen (3,1 µg bzw. 1,2 µg pro ml Serum) jeweils 12 Stunden post natum ermittelt. Diese cIgG-Konzentrationen nahmen danach kontinuierlich auf Konzentrationen von 1,1 µg bzw. 0,2 µg pro ml Serum zum Zeitpunkt 96 Stunden post natum ab. Bezogen auf die mit der ersten Tränke verabreichte bIgG- bzw. cIgG-Menge wurde überschlagsweise zum Zeitpunkt 6te Lebensstunde eine Anflutung im Blut von 23 % (bIgG) bzw. von 7 % und 6 % (cIgG) errechnet. Der zeitliche Verlauf (6te bis 96te Stunde) der Konzentration des bovinen IgGs in den Blutproben war vergleichsweise stabil und lag durchschnittlich bei 5,9 mg pro ml Serum, wobei das Plateau bereits nach 6 Stunden erreicht war. Signifikante Unterschiede zwischen den bIgG-Werten der Kälber, die Dotterantikörper bekamen (6,2 bzw. 6,1 mg pro ml Serum), und denen der Kontrollgruppe (5,4 mg pro ml Serum) waren nicht zu beobachten. Eipulver kann somit offensichtlich zur Prophylaxe bei neugeborenen Kälbern ohne Beeinträchtigung der Absorption der kolostralen Antikörper verabreicht werden. Allerdings muß bei einer Eipulververgabe mit der ersten Tränke auch mit einer Absorption von aviären Dotterantikörpern gerechnet werden.
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  • 50
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    European journal of nutrition 34 (1995), S. 190-197 
    ISSN: 1436-6215
    Keywords: Verzehrserhebungen ; Nationale Verzehrsstudie ; Lebensmittelverzehr ; internationaler Vergleich von Verzehrserhebungen ; Dietary surveys ; national food consumption study ; food intake ; international comparison of dietary surveys
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
    Description / Table of Contents: Summary Referring to the data of the National Food Consumption Study in Germany and the Dietary and Nutritional Survey of British Adults, this article compares the food intake of German and British adults. Such a comparison is possible because both studies have mainly the same methodology. The comparison of the food intake of German and British adults points out food groups which Germans consume inhigher amounts than British people do. To this category belong meat products and sausages, eggs, cheese and cottage cheese, butter, fat for cooking and salad oil, bread and pastries, vegetables, fruit, preserves and soft drinks. The Germans consumeless meat, fish and fish products, milk and milk products, pasta, rice and miscellaneous cereals, potatoes, sugar, sweets and tea than the British people do. The consumption of fruit products, alcoholic beverages and coffee is nearly the same in Germany and Great Britain.
    Notes: Zusammenfassung Anhand der Nationalen Verzehrsstudie und des „Dietary and Nutritional Survey of British Adults“ wird der Lebensmittelverzehr der Erwachsenen in Deutschland und Großbritannien verglichen. Dies ist möglich, weil die Methodik weitgehend übereinstimmt. Beim Vergleich des Lebensmittelverzehrs von Deutschen und Briten fallen Lebensmittel auf, von denen die Deutschenmehr zu sich nehmen als die Briten. Dazu gehören Fleisch- und Wurstwaren, Eier, Käse und Quark, Butter, Speisefette und -öle, Brot und Backwaren, Gemüse, Obst, Marmelade/Konfitüre und alkoholfreie Getränke. Die Deutschen nehmen dagegenweniger Fleisch, Fisch und Fischwaren, Milch und Milchprodukte, Nährmittel, Kartoffeln, Zucker, Süßwaren und Tee zu sich als die Briten. Beim Konsum von Obstprodukten, alkoholischen Getränken und Röstkaffee herrschen nur geringfügige Unterschiede zwischen Deutschen und Briten.
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  • 51
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    European journal of nutrition 34 (1995), S. 206-213 
    ISSN: 1436-6215
    Keywords: Fischöl ; Olivenöl ; Überernährung ; Sauen ; Energiebilanz ; Thermogenese ; Gaswechsel ; Fish oil ; olive oil ; overfeeding ; sows ; energy balance ; thermogenesis ; gaseous exchange
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
    Description / Table of Contents: Summary A trial on total metabolism was conducted in eight nonpregnant, nonlactating sows over eight periods, each of 16 days duration, to measure potential fatty acid induced thermogenesis. During the first and last experimental periods, the animals received a basal ration which just covered the energy maintenance requirement. In the second to seventh periods supplements of olive oil, fish oil, or puffed wheat starch as reference nutrient were added to the diet in random sequence at two levels up to 50 % above the maintenance requirement. All rations were calculated with reference to the sows' initial weight and remained quantitatively unchanged throughout the experiment. The animals were fed twice daily. During each metabolism period a complete energy balance was assessed for all sows by means of collection technique (feed, feces, urine), and 48-h measurements of the gas exchange in a respiration chamber. The sows' body mass increased linearly during the course of the experiment by 5.8 kg per period. The three supplement types had no influence on the animals' final body weight, wich averaged 205.5 kg with the starch supplement, 204.8 kg with olive oil, and 205.8 kg with fish oil. Energy digestibility (DE/GE) was 100 % for all three supplements, and metabolizability of energy (ME/GE) one percentage point less. Carbon and energy depositions showed a pronounced linear relationship to the level of supplementation and were also influenced by the type of supplement. Heat production was 20.9 MJ/d after feeding the basal ration alone and, taking the average of the two supplementation levels, 21.6 MJ for the starch supplement, 21.0 MJ for olive oil, and 20.6 MJ for fish oil. The relationship between energy deposition and the supply of ME resulted in regression coefficients of 0.9 MJ/MJ after feeding starch and 1.0 MJ/MJ after feeding the two oils. It can be concluded from these results that supplementation of the diet with fat containing mono- or polyunsaturated fatty acids above the energetic maintenance requirement under conditions of severely restricted movement (respiration chamber) has no influence on thermogenesis and consequently causes a deposition of energy equivalent to the amount supplied with the dietary fat.
    Notes: Zusammenfassung Zur Messung einer fettsäureninduzierten Thermogenese wurde ein Gesamtstoffwechselversuch mit 8 nichtgraviden, nichtlaktierenden Sauen über 8 Perioden von jeweils 16 Tagen Dauer durchgeführt. Die Tiere erhielten in der ersten und letzten Versuchsperiode eine den energetischen Erhaltungsbedarf deckende Grundration. In Periode 2 bis 7 wurden in zufälliger Reihenfolge Olivenöl, Fischöl bzw. als Referenznährstoff Weizenquellstärke in jeweils 2 Mengenstufen bis 50 % über das Erhaltungsniveau zugelegt. Alle Rationen wurden aufgrund der Anfangsmasse der Sauen eingestellt und über den gesamten Versuch in unveränderter Menge beibehalten. Die Fütterung erfolgte zweimal täglich. Von allen Tieren wurde in jeder Stoffwechselperiode eine vollständige Bilanzmessung mit Sammeltechnik (Futter, Kot, Harn) und 48stündiger Messung des Gaswechsels in der Respirationskammer durchgeführt. Die Körpermasse der Sauen stieg im Versuchsablauf linear um 5,8 kg je Zulageperiode an. Die drei Zulagearten hatten keinen Einfluß auf die Körpermasse der Tiere, sie wogen im Mittel bei Stärkezulage 205,5 kg, bei Olivenöl und Fischöl 204,8 bzw. 205,8 kg. Die Verdaulichkeit der Energie (DE/GE) betrug bei allen drei Zulagen 100 %, die Umsetzbarkeit der Energie (ME/GE) einen Prozentpunkt weniger. Der Kohlenstoffund Energieansatz zeigte eine ausgeprägte lineare Abhängigkeit zur Zulagenhöhe sowie einen signifikanten Effekt der Zulagenart. Die Wärmebildung betrug bei alleiniger Fütterung der Grundration 20,9 MJ und im Mittel der beiden Zulagestufen bei Stärkefütterung 21,6 MJ und bei Olivenöl und Fischöl 21,0 bzw. 20,6 MJ/d. Die Abhängigkeit des Energieansatzes von der Zufuhr an ME ergab Regressionskoeffizienten von 0,9 MJ/MJ bei Verabreichung von Stärke und 1,0 MJ/MJ bei Fütterung der beiden Öle. Aus den Ergebnissen ist zu folgern, daß eine Zulage von Fetten mit einfach oder mehrfach ungesättigten Fettsäuren über dem energetischen Erhaltungsbedarf unter der Bedingung stark eingeschränkter Bewegungsaktivität (Respirationskammer) keinen Einfluß auf die Thermogenese und somit einen energetischen Ansatz entsprechend der zugeführten Energie des Nahrungsfettes bewirkt.
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  • 52
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    European journal of nutrition 34 (1995), S. 269-276 
    ISSN: 1436-6215
    Keywords: Iod ; Uriniod ; Quotient Uriniod/Urinkreatinin ; Iodresorption ; Iodbioverfügbarkeit ; Nahrungsiod ; Iodine ; urinary iodine ; quotient iodine in urine/creatinine in urine ; iodine absorption ; iodine bioavailability ; alimentary iodine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
    Description / Table of Contents: Summary The standard food for our volunteers, prepared in the central kitchen of the University Hospital of Tuebingen, consisted of breakfast, warm lunch and cold supper and contained, on average, approximately 230 µg of iodine/day. It is generally assumed that an equilibrium is established between iodine intake from food and urinary iodine excretion. Hence, the amount of iodine excreted with the urine within 24 h may reflect the daily ingestion of iodine. The fecal iodine losses are considered negligible. The alimentary iodine supply from food of our clinic would meet the WHO recommendations of 〉150 µg/day to prevent iodine-deficiency goiters. In 27 healthy volunteers the daily uptake of iodine was determined and the urinary excretion of iodine within 24 h was measured. Unexpectedly, only 16 % to 18 % of the alimentary iodine were excreted with the urine. Hence, the utilization of iodine from the food appears to be limited and therefore cannot prevent goiters in goiter areas. In addition, it was found that the correlation between urinary excretion of iodine and urinary excretion of creatinine is not a reliable parameter for the real daily excretion of iodine and iodine balance.
    Notes: Zusammenfassung Die Verpflegung (Frühstück, Mittagessen und Abendessen) aus der Zentralküche des Universitätsklinikums in Tübingen enthält durchschnittlich 230 µg Iod/Tag. Bei Personen, die täglich an dieser Verpflegung teilnehmen, stellt sich ein Gleichgewicht zwischen Iodaufnahme und renaler Iodausscheidung ein. Die Iodausscheidung über die Faeces gilt als vernachlässigbar. Die in unserer Klinikverpflegung angebotene Iodmenge entspricht dem von der WHO geforderten Angebot von 〉150 µg Iod/Tag, um endemische Strumen zu verhindern. Bei 27 gesunden Probanden wurden die tägliche Iodaufnahme und die zugehörige Ausscheidung von Iod im 24-h-Urin ermittelt. Dabei zeigte sich überraschend, daß vom angebotenen Iod nur 16 % bis 18 % mit dem Urin ausgeschieden wurden. Das mit der Nahrung angebotene Iod steht offenbar dem Organismus nur begrenzt zur Verfügung und kann Strumen in Iodmangelgebieten nicht verhindern. Der Bezug der Uriniodausscheidung auf das Kreatinin liefert nur einen groben Parameter für die tägliche Iodausscheidung und für die Iodbilanzierung.
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  • 53
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    European journal of nutrition 34 (1995), S. 261-268 
    ISSN: 1436-6215
    Keywords: Auswahl von Mahlzeiten ; Einschätzung von Mahlzeiten ; Gesundheitswert ; Entwicklungsstand ; Ernährungserziehung ; Selection of meals ; estimation of meals ; value of health ; age differences ; education of nutrition
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
    Description / Table of Contents: Summary With regard to the reported knowledge concerning the health value of food in 9–10-year-old children (DGE, 1984) the question arose of whether this knowledge is also valid if pupils have to evaluate meals. Twenty-seven photos of meals (9 each of breakfast, lunch and supper) were presented to 252 children of the age groups 6–7, 9–10 and 12–13 years. By means of these photos, they were requested to organize their meals for 3 days. Subsequent to this procedure the children were asked to evaluate the meals with regard to their health value. The presented meals were classified by five experts of nutrition as more healthy, indifferent and less healthy. The results showed an improved selection of more healthy meals with increasing age. Likewise, the selection of meals for lunch and supper was better than the one for breakfast. There were no differences between boys and girls and children with and without experience of dieting. The evaluation of more healthy and less healthy meals demonstrated an improvement with increasing age. In contradiction to these results, children within all age groups showed a very low level of estimation (10 %) for indifferently classified meals and this level did not improve with increasing age. The results were discussed concerning the establishment of an appropriate education of nutrition with regard to the developmental stage and the emotional and motivational engagement of the children.
    Notes: Zusammenfassung Im Hinblick auf die relativ gute Bewertung einzelner Nahrungsmittel durch 9–10jährige Kinder (DGE, 1984) stellte sich die Frage, ob dieses Wissen gleichfalls für die Einschätzung von Mahlzeiten gilt. 252 Kinder der Altersgruppe 6–7 Jahre, 9–10 Jahre und 12–13 Jahre wurden daher 27 Fotos von Mahlzeiten (je 9mal Frühstück, Mittagessen und Abendbrot) vorgelegt. Die Kinder wurden aufgefordert, ihre Mahlzeiten auf der Basis der vorgelegten Fotos für 3 Tage zusammenzustellen. Danach wurden die Kinder befragt, wie sie die Mahlzeiten bezüglich ihres Gesundheitswertes einschätzen würden. Die vorgelegten Mahlzeiten waren von 5 Experten zuvor als „eher gesund“, „mittelmäßig gesund“ und „eher ungesund“ eingestuff worden. Die Ergebnisse weisen auf eine häufigere Auswahl „eher gesunder“ Mahlzeiten mit ansteigendem Alter hin. Die Auswahl für das Mittagessen und das Abendbrot war unter dem Aspekt des Gesundheitswertes in allen Altersstufen besser als die Auswahl für das Frühstück. Es zeigten sich keine deutlichen Unterschiede zwischen Jungen und Mädchen und Kindern mit und ohne Diäterfahrung. Die Einschätzung der „eher gesunden“ bzw. „eher ungesunden“ Mahlzeiten verbesserte sich gleichfalls mit zunehmendem Alter. Andererseits fand sich bei der Einschätzung der als „mittelmäßig gesund“ eingestuften Mahlzeiten ein recht niedriges Niveau in der richtigen Einschätzung (etwa 10 %) auf allen 3 Altersstufen. Die Ergebnisse werden im Zusammenhang mit gegenwärtigen und künftigen Maßnahmen in der Ernährungserziehung diskutiert, wobei aufgrund der Ergebnisse Entwicklung und Motivation und die emotionalen Bedürfnisse der Kinder stärker zu berücksichtigen sind.
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  • 54
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    European journal of nutrition 34 (1995), S. 166-166 
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    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
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  • 55
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    European journal of nutrition 34 (1995), S. 167-176 
    ISSN: 1436-6215
    Keywords: Vitamin C ; Vitamin E ; β-Carotin ; antioxidative Vitamine ; Vitaminaufnahme ; Augenlinse ; Katarakte ; Alter ; Vitamin C ; vitamin E ; β-carotene ; antioxidant vitamins ; vitamin intake ; ocular lens ; cataracts ; elderly
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
    Description / Table of Contents: Summary Senile cataract indicates the opacity of ocular lenses occuring in old and especially in very old people. Lens proteins are extremely long-living and often show oxidative damages. Aging and smoking appear to be the greatest risk factors for the development of lens opacities. The sufficient antioxidant protection of young lenses decreases with the aging process. Consequently, the importance of other protective factors increases. Nutritional factors, particularly vitamins with antioxidant properties, may influence the development of senile cataracts in the ocular lens. Meanwhile an association between the supply with vitamin C, E and β-carotene and the risk of cataract development was demonstrated in animal studies and also in an increasing number of epidemiological studies. These epidemiological studies mainly support the hypothesis that higher vitamin intakes reduce the risk of developing cataracts in old age. The antioxidant properties of the named nutrients give a plausible explanation for the mechanism of cataractogenesis. On the basis of the present data definitive recommendation, necessary for cataract prevention can not yet be established. Some results seem to support higher recommendations. At the moment several large human intervention trials are carried out. Form these studies a further confirmation of the antioxidant hypothesis and of a dose-response-relationship are expected.
    Notes: Zusammenfassung Die senile Katarakt ist eine im Alter und besonders häufig im hohen Alter auftretende Trübung der Augenlinsen. Die extrem langlebigen Linsenproteine weisen häufig oxidationsbedingte Schädigungen auf. Altern und Rauchen erscheinen als die größten Risikofaktoren für eine Kataraktbildung. Während junge Augenlinsen in der Regel über eine ausreichende antioxidative Schutzkapazität verfügen, nimmt diese mit dem Alter ab. Damit wächst die Bedeutung anderer Schutzfaktoren. Nahrungsfaktoren, besonders Vitamine mit antioxidativen Eigenschaften, schützen möglicherweise vor einer Bildung von senilen Katarakten in den Augenlinsen. Ein Zusammenhang zwischen der Versorgung mit Vitamin C, E und β-Carotin und dem Kataraktrisiko konnte in tierexperimentellen Untersuchungen aufgezeigt und inzwischen auch in einer wachsenden Zahl epidemiologischer Studien nachgewiesen werden. Die bisher vorliegenden epidemiologischen Studien unterstützen mehrheitlich die Hypothese, daß erhöhte Vitaminaufnahmen das Risiko einer Kataraktbildung reduzieren. Die antioxidative Wirkung der genannten Nährstoffe liefert eine plausible Erklärung für den Mechanismus der Kataraktgenese. Es fehlen aber noch Studien, aus denen sich die für eine Prävention notwendigen Vitaminmengen ableiten lassen. Einige Untersuchungsergebnisse sprechen möglicherweise dafür, daß diese über den bisher geltenden Empfehlungen liegen. Zur Zeit werden verschiedene, große Interventionsstudien durchgeführt, die eine weitere Absicherung der Antioxidanshypothese und von Dosis-Wirkungsbeziehungen erwarten lassen.
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  • 56
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    Keywords: Ovariectomy ; pig ; bone histology ; calcitriol ; parathyroid hormone ; alkaline phosphatase ; Ovariektomie ; Schwein ; Knochenhistologie ; Calcitriol ; Parathormon ; alkalische Phosphatase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
    Description / Table of Contents: Zusammenfassung In der vorliegenden Untersuchung sollte die Eignung des ovariektomierten Schweins als Modell für die postmenopausale Osteoporose beschrieben werden. Hierzu wurde der Einfluß der Ovariektomie (OVX) auf Plasmaparameter des Knochenstoffwechsels und auf knochenhistologische Parameter bei zwei Gruppen von Sauen (9 Monate alt, Nullipara oder 35 Monate alt, Multipara) untersucht. Eine Standarddiät für Schweine mit einem Calciumgehalt von 1,5 % wurde verabreicht. Gesamt-und knochenspezifische alkalische Phosphatase (APt, APb) Calcidiol, Calcitriol und Parathormon (PTH) wurden im Plasma 4, 8, 12 und 18 Monate nach OVX bestimmt. Der Mineralgehalt sowie histologische Parameter wurden in repräsentativen Knochenproben 12 Monate nach OVX und am Ende des Versuchs 18 Monate nach OVX gemessen. Bei jungen Sauen führte die Ovariektomie zu keinen signifikanten Veränderungen der Plasmaparameter mit Ausnahme höherer Konzentrationen des Calcitriols 4 Monate nach OVX. Es wurden weder 12 noch 20 Monate nach OVX signifikante Unterschiede zwischen OVX- und Kontrolltieren in den Parametern der chemischen oder histologischen Knochenanalyse beobachtet. Bei multiparen Sauen waren die Plasmakonzentrationen des PTH gegenüber den Kontrolltieren 8 Monate nach OVX signifikant erhöht. Die Konzentrationen des Calcitriols sowie die Aktivität der APt und APb lagen 12 Monate nach OVX signifikant über den Werten der intakten Tiere. Alle Effekte waren moderat. Weder 12 Monate noch 20 Monate nach OVX kam es zu signifikanten Veränderungen in den Parametern der chemischen oder histologischen Knochenanalyse. Obwohl die beobachteten Veränderungen in den klinisch-chemischen Plasmaparametern zweifellos keine histomorphometrischen Anzeichen einer Osteopenie/Osteoporose zur Folge hatten, bleibt es zukünftigen Untersuchungen überlassen nachzuprüfen, ob das Ausbleiben des Osteopenie ein Ergebnis der in diesem Experiment hohen Calciumzufuhr war. Eine solche Möglichkeit sollte aufgrund der Beobachtung in Betracht gezogen werden, daß Osteopenie beim Schwein nach OVX eintritt, wenn eine Diät mit geringerer Calciumzufuhr (0,75 % im Vergleich zu 0,9 %) verabreicht wurde (33).
    Notes: Summary To investigate the suitability of the pig as animal model for postmenopausal osteoprosis, effects of ovariectomy (OVX) on bone metabolism and histology were studied in two groups of sows (9 months, nulliparous or 35 months, multiparous). A standard diet of about 1.5 % calcium (Ca) was fed till sacrifice at either 12 or 20 months post OVX when mineral content and histology were studied in representative bone specimens of proximal tibia, iliac crest and lumbar vertebrae. At 4, 8, 12, and 18 months post OVX, total and bone-specific alkaline phosphatase (APt, APb) calcidiol, calcitriol and parathyroid hormone (PTH) were measured in plasma. In young sows OVX did not significantly affect plasma variables except for calcitriol, which was higher at 4 months post OVX. No significant differences between OVX or control animals were observed in the variables of bone chemical and histological analyses, neither 12 nor 20 months post OVX. In multiparous sows OVX significantly increased PTH plasma concentrations at 8 months post OVX and plasma calcitriol, APt and APb at 12 months post OVX. All effects were moderate and transient. OVX did not significantly affect the variables of bone chemical and histological analyses neither 12 nor 20 months post OVX. Although undoubtedly the clinical-chemical changes observed were not accompanied by any histomorphometric signs of osteopenia/osteoporosis, it must be left to future experiments as to whether this resulted from the ample calcium supply provided. This possibility is supported by recent observations showing that porcine osteopenia could be induced by OVX in animals maintained on only 0.75 % dietary calcium but not on higher (0.9 %) Ca regimens (33).
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  • 57
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    European journal of nutrition 34 (1995), S. 240-242 
    ISSN: 1436-6215
    Keywords: Iodine ; iodized salt ; canteen ; lunch meals ; sodium chloride ; Jod ; jodiertes Speisesalz ; Großküche ; Mittagessen ; Natriumchlorid
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
    Description / Table of Contents: Zusammenfassung In zwei Universitäts-Großküchen, die für die Nahrungszubereitung jodiertes Speisesalz immer (Mensa A) oder nie (Mensa B) verwendeten, wurden 15 möglichst gleiche Mittagessen gesammelt und auf ihre Gehalte an Jodid und NaCl analysiert. Bei durchschnittlich ähnlichem Kochsalzgehalt enthielt das Essen in Mensa A im Mittel 6,1 µg I/100 g ww (8,5 µg I/g NaCl) mehr Jod als in Mensa B. Die Gesamtjodaufnahme mit einem durchschnittlichen Mittagessen in Mensa A betrug demnach 56,5±24,1 µg (Mensa B: 17,0±9,9 µg). Dem Einsatz von jodiertem Speisesalz in der Gemeinschaftsverpflegung scheint somit eine wichtigere Rolle auf dem Weg zu einer ausreichenden Jodaufnahme zuzukommen als bisher angenommen wurde.
    Notes: Summary In each of two university canteens differing in the use (canteen A) or non-use (canteen B) of iodized salt for food preparation, 15 mostly equal lunch meals were collected for iodide and NaCl analysis. With similar NaCl content, the meals of canteen A contained on average 6.1 µg I/100 g ww (8.5 µg I/g NaCl) more I than the meals of canteen B. Total I intake by consumption of an average meal of canteen A was estimated as 56.5±24.1 µg (canteen B: 17.0±9.9 µg). Consequently, the use of iodized salt in central catering seems to play a more important role in a sufficient I intake than assumed so far.
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  • 58
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    European journal of nutrition 34 (1995), S. 284-292 
    ISSN: 1436-6215
    Keywords: Human placenta ; brush border membrane ; alanine transport ; group specific reagents ; SH-groups ; Alanintransport ; menschliche Plazenta ; Kinetik ; gruppenspezifische Reagentien ; SH-Gruppen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
    Description / Table of Contents: Zusammenfassung Transportsysteme in der apikalen Zellmembran der Syncytiothrophoblasten der Plazenta sind für den Nährstoff-transport aus dem mütterlichen Kreislauf in den fetalen Stoffwechsel von elementarer Bedeutung für Wachstum und Entwicklung des Fötus. Die Carriersysteme für Aminosäuren limitieren dabei die Versorgung des Fötus mit essentiellen und nicht essentiellen Aminosäuren. An isolierten Bürstensaummembranvesikeln (BBMV) reifer menschlicher Placenta haben wir die Aufnahme von neutralen Aminosäuren am Beispiel von Alanin charakterisiert. Darüber hinaus wurden durch den Einsatz gruppenspezifischer Reagentien wichtige Aminosäureseitengruppen der entsprechenden Transportproteine identifiziert. Die Alaninaufnahme in die BBMV wird durch zwei sättigbare Carriersysteme mit unterschiedlichen Eigenschaften vermittelt. Neben einem elektrogenen Na+-abhängigen System, das auch Gln, meAIB und Met transportiert, existiert ein Na+-unabhängiges System, das kein meAIB, dafür aber zusätzlich Leu und Tyr transportiert. Beide Transportsysteme haben gleiche Affinitätskonstanten (Km-Werte) für Alanin (0,45±0,06 mmol/l). Das Na+-abhängige System transportiert Alanin mit einer 1:1 Stöchiometrie mit Na+-Ionen und weist eine 3fach höhere maximale Transportgeschwindigkeit auf. Durch Einsatz gruppenspezifischer Reagentien wurden freie SH-Gruppen in den beiden Carriern identifiziert, die für die Funktion von entscheidender Bedeutung sind. Durch Oxidation und Rückreduktion der SH-Gruppen konnte die Transportleistung der Carrier reversibel verändert werden. Da die modifizierenden Reagentien die SH-Gruppen auch in Gegenwart der Substrate blockierten, ist zu vermuten, daß die wichtigen SH-Gruppen nicht in der Substratbindungsstelle der Transportproteine liegen.
    Notes: Summary We have determined the kinetic characteristics of alanine transport into brush border membrane vesicles (BBMV) of human full term placenta and identified functional groups of the carrier proteins that are important for transport function. Alanine influx into BBMV was found to be mediated by two transport systems with different kinetic features and distinct substrate specificities. An uphill operating electrogenic Na+-dependent contransport system could be kinetically separated from a Na+-independent facilitated diffusion system. The Na+-dependent transporter mediates Na+-alanine cotransport with a 1:1 flux coupling ratio (Hill coefficient 1.13±0.12) and a Km for alanine of 0.45±0.06 mmol/l. Halfmaximal stimulation of Na+-dependent alanine influx was observed at a Na+ concentration (NaCl) of 51.4±1.3 mmol/l. A variety of group specific reagents were used to identify functional groups in the transport proteins. Only compounds reacting with SH-residues (NEM, DTNB, PCMBS) or NH2-groups (PITC) were found to affect Na+ dependent and Na+ independent alanine transport. The EC50 value for inhibition of alanine influx by PCMBS was 450±48 µmol/l. Chemical modifications of SH-groups by PCMBS caused a significant reduction (p〈0.005) in the Vmax for Na+-dependent alanine influx from 0.57±0.06 to 0.16±0.05 nmol·mg protein−1·10s−1 without affecting significantly the Km value. Inhibition by PCMBS was reversed by treatment of BBMV with DTT. When the substrate binding site of the transporter was protected by alanine or leucine, PCMBS still blocked transport function, indicating that the cruical SH groups are not located within the substrate binding site of the transport proteins.
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  • 59
    ISSN: 1436-6215
    Keywords: Iodine prophylaxis ; iodized salt ; iodine excretion ; hyroid volume ; Jod ; Jodsalz ; Jodausscheidung ; Schilddrüsenvolumen ; Jodprophylaxe
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
    Description / Table of Contents: Zusammenfassung Im Rahmen einer Gesundheitskampagne zu Jodmangel und Jodprophylaxe an fünf süddeutschen Universitäten wurde 1992 das Schilddrüsenvolumen und die renale Jodausscheidung bei 472 Männern und 568 Frauen (mittleres Alter 27,7 Jahre) bestimmt. Ziel war es den Einfluß des Ernährungswissens und der durchgeführten Jodprophylaxe auf den Jodversorgungsstatus der Studienteilnehmer in einem Jodmangelgebiet zu untersuchen. Das mittlere Schilddrüsenvolumen betrug 19,7±8,3 ml (x±SD) bei den Männern und 15,8±7,1 ml bei den Frauen. 19,9 % der Männer und 25,5 % der Frauen wiesen Schilddrüsenvolumina über der geschlechtspezifischen Norm auf. Die mittlere Jodausscheidung entsprach dem WHO-definierten Jodmangel Grad I (70,7±42 µg (J/g Kreatinin). 80,8 % bzw. 43,2 % des Gesamtkollektivs gaben an, Jodsalz zu verwenden bzw. Seefisch zu essen, um ihren Jodbedarf zu decken. Die korrespondierende Jodausscheidung der weiblichen Jodsalzverwender und Seefischesser war signifikant erhöht (83,9±47,6 vs. 61,4±31,3 µg J/g Kreatinin, p〈0,05). Das Schilddrüsenvolumen unterschied sich zwischen diesen Gruppen jedoch nicht. Der Aufenthaltsort der letzten 10 Jahre hatte keinen signifikanten Einfluß auf das Schilddrüsenvolumen. Die Häufigkeit von Schilddrüsenvolumina über der geschlechtsspezifischen Norm stieg mit dem Alter. Auch in diesem überdurchschnittlich gebildeten und jungen (81,8 % Studenten) Kollektiv war die Jodversorgung, gemessen am Schilddrüsenvolumen und an der Jodausscheidung, und das Wissen über Jod und Ernähung schlecht. Die derzeit durchgeführte individuelle Jodprophylaxe führt nicht zu einer ausreichenden Jodversorgung. Der Einsatz von jodiertem Speisesalz in Haushalten und Kantinen, und auch für die industrielle Herstellung von Lebensmitteln muß erhöht werden.
    Notes: Summary Thyroid volume, urinary iodine excretion as well as personal nutritional knowledge and individual iodine prophylaxis were determined during a health education program on iodine deficiency and prophylaxis in 1992. Participants were 472 male and 568 female (mean age 27.7 years) students and employees of five universities in the southern part of Germany. The study aimed to clarify the relationship between personal knowledge on iodine, individual iodine prophylaxis and parameters of iodine deficiency (thyroid volume, iodine excretion) in a well known iodine deficient area. Mean thyroid volume (mean±SD) was 19.7±8.3 ml in males and 15.8±7.1 ml in females. 25.5 % of females and 19.9 % of males showed thyroid volume above the upper normal values. Total mean urinary iodine excretion was 70.7±42 µg I/g creatinine reflecting WHO-grade-I iodine deficiency. 80.8 % of total subjects used iodized salt and 43.2 % stated to consume salt-water fish to meet their iodine requirement. The female non-users had significantly lower iodine excretion (no iodized salt, no salt-water fish: 61.4±31.3 vs. +iodized salt, +salt-water fish: 83.9±47.6 µg I/g creatinine; p〈0.05), however, thyroid volume was identical in these groups. The area of residence over the last 10 years did not significantly influence the thyroid volume. The goiter incidence increased with age. Although our study population was highly educated (81.8 % students) and the subjects were provided with educational brochures immediately prior to the study, knowledge about iodine content of food was poor. We conclude that despite a high degree of voluntary iodine prophylaxis and educational programs the iodine intake is insufficient. The use of iodized salt in households, cafeterias, and also in food manufacturing must be increased for sufficient iodine prophylaxis.
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  • 60
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    European journal of nutrition 35 (1996), S. 32-38 
    ISSN: 1436-6215
    Keywords: Dietary fiber ; dehydroepiandrosterone sulfate ; dehydroepiandrosterone ; 3α-androstanediol glucuronide ; peptide ; steroid metabolism ; Diätetischer Ballaststoff ; Dehydroepiandrosteronsulfat ; Dehydroepiandrosteron ; 3α-Androstendiol glucuronide ; steroidmetabolismus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
    Description / Table of Contents: Zusammenfassung Es gibt kaum Untersuchungen zu den Auswirkungen einzelner Nahrungskomponenten auf die Plasmaspiegel von Dehydroepiandrosteron (DHEA) und Dehydroepiandrosteron-Sulfat (DHEAS). Insbesondere fehlen Studien zum Einfluß von speziellen Ballaststoffen. Der Effekt von Pektin (ein typischer Ballaststoff mit Wirkung auf die enterohepatische Rezirkulation von Gallensäuren) wurde in 3 aufeinanderfolgenden, jeweils 4tägigen Diätphasen an 6 männlichen Erwachsenen im Rahmen einer randomisierten cross-over-Studie überprüft. Am Ende jeder Diätphase (konstante Nahrungszusammensetzung, Pektinzusatz: 0, 15 bzw. 30 g/die) wurden 24h-Urine gesammelt und venöses Blut entnommen. Die Pektinzulagen führten weder bei DHEA und Cortisol noch beim wichtigsten Plasmabindungsprotein von DHEAS, dem Albumin, zu Veränderungen der Plasmakonzentrationen. Auch blieb die Ausscheidung verschiedener Urin-Analyte (einschließlich des DHEAS) konstant. Allerdings zeigten sich bei 30 bzw. 15 versus 0 g Pektin/die Effekte in bezug auf Plasma-DHEAS (9,3±2,8; 9,2±2,6; 8,0±3,1 µmol/L, p〈0,01) und Plasma-Cholesterin (4,4±0,7; 4,5±0,7; 4,7±0,8 mmol/L, p=0,1). Die Auswirkungen einer veränderten Pektinzufuhr auf zirkulierendes DHEAS und Cholesterin sind also offensichtlich entgegengerichtet. Die Ursache hierfür ist nicht bekannt, allerdings wird eine diätetisch induzierte Änderung der Bindungseigenschaften von Albumin für DHEAS vermutet. Die Befunde deuten an, daß der biologisch aktive, nicht proteingebundene Anteil des zirkulierenden DHEAS (der durch die renale DHEAS-Ausscheidung reflektiert wird) nicht notwendigerweise verändert sein muß, wenn das Gesamt-DHEAS im Plasma variiert.
    Notes: Summary Studies specifically investigating the effects of single dietary components on plasma levels of dehydroepiandrosterone (DHEA) and its sulfate ester (DHEAS) are rare. Especially no data is available with regard to specific dietary fibers. Therefore, the impact of pectin (a representative fiber that affects the enterohepatic recirculation of bile acids) was studied in a randomized crossover trial consisting of three diet periods characterized by the same food supply and daily doses of 0 g, 15 g or 30 g pectin. Blood and 24-h-urine samples were collected at the end of each 4-day diet period from 6 healthy male volunteers. Plasma levels of DHEA, cortisol and the major binding protein of DHEAS albumin remained unchanged with the varying pectin supplements. Also, no changes were observed for several urinary analytes including urinary DHEAS. However, effects of pectin intake (30, 15 versus 0 g/d) were seen for plasma DHEAS (9.3±2.8, 9.2±2.6, 8.0±3.1 µmol/L, p〈0.01) and total plasma cholesterol (4.4±0.7, 4.5±0.7, 4.7±0.8 mmol/L, p=0.1). Obviously, the altered intake of fiber in the form of pectin affects plasma concentrations of DHEAS and cholesterol in an opposite direction. The reason for this is not known but a dietetically induced modulation of the binding properties of plasma albumin for DHEAS appears possible. Our findings suggest that the target tissue-available, not protein-bound fraction of circulating DHEAS (as reflected by the renal DHEAS output) is not necessarily altered when total plasma concentrations of DHEAS vary.
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    European journal of nutrition 35 (1996), S. 57-58 
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  • 62
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    European journal of nutrition 35 (1996), S. 59-119 
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    Source: Springer Online Journal Archives 1860-2000
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  • 63
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    European journal of nutrition 35 (1996), S. 157-162 
    ISSN: 1436-6215
    Keywords: Empfehlungen zur Nährstoffzufuhr ; historische Entwicklung ; Recommended Dietary Allowances ; historical development
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
    Description / Table of Contents: Summary The discovery of the preventive action of lemon juice against scorbut led to a first recommendation on dietary intake in 1753. During the tight economic situation of the following century and in face of the economic crisis after the World War I, several concepts of dietary recommendations developed, all of which primarily served to relieve starvation and hunger and to maintain the ability to work of males. Increasing knowledge of human requirements for essential nutrients led to a clear distinction between dietary standards and health policy recommendations. With their first set of Recommended Dietary Allowances in 1941, especially the American Food and Nutrition Board directed concepts towards the improvement and maintenance of health of all people. National and international work on dietary recommendations took place to an increased extent in the 1970s. In face of currently expanding demands on dietary recommendations at present new directives for the revision of the American Recommended Dietary Allowances are discussed.
    Notes: Zusammenfassung Die Entdekkung der präventiven Wirkung von Zitronensaft gengen Skorbut führte 1753 zu einer ersten Empfehlung zur Nährstoffzufuhr. In den wirtschaftlich angespannten Jahren des folgenden Jahrhunderts und vor dem Hintergrund der Wirtschaftskrise nach dem 1. Weltkrieg entwikkelten sich mehrere Konzepte zu Empfehlungen für die Nährstoffzufuhr, welche primär der Erhalt der Arbeitsfähigkeit der Männer und die Bekämpfung des Hungers zum Ziel hatten. Mit zunehmenden Erkenntnissen zum Bedarf des Menschen an essentiellen Nährstoffen kam es zu einer deutlichen Unterscheidung zwischen bisherigen Empfehlungen und Empfehlungen auf der Basis gesundheitspolitischer Erwägungen. Insbesondere das amerikanische Food and Nutrition Board lenkte mit seiner ersten Ausgabe der Recommended Dietary Allowances 1941 die Ansprüche an die Empfehlungen zur Nährstoffzufuhr in Richtung der Verbesserung und Aufrechterhaltung des Gesundheitszustandes der gesamten Bevölkerung. Seit den 70er Jahren erfolgt eine verstärkte nationale und internationale Arbeit auf dem Gebiet der Nährstoffempfehlungen. Vor dem Hintergrund der wachsenden Anforderungen an die Empfehlungswerte werden derzeit neue Direktiven für die Revision der amerikanischen Recommended Dietary Allowances diskutiert.
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  • 64
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    European journal of nutrition 35 (1996), S. 206-207 
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    Source: Springer Online Journal Archives 1860-2000
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  • 65
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    European journal of nutrition 35 (1996), S. 199-205 
    ISSN: 1436-6215
    Keywords: α-Amylase Inhibitoren ; lösliches Arabinoxylan ; Roggen ; postprandiale Glykämie ; diabetische Ratten ; Type-II-Diabetiker ; α-amylase-inhibitors ; soluble arabinoxylan ; rye ; postprandial glycemia ; diabetic rats ; type-II-diabetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
    Description / Table of Contents: Summary The protein inhibitor of the α-amylase (D-type) and the soluble arabinoxylan of rye (Var. Clou) were isolated from flour and bran, respectively. The isolation of the α-amylase inhibitor involves the extraction of rye flour in aqueous CaCl2-solution (2 × 10−3M) containing the hemicellulase preparation Veron HE (2 g/100 g flour), dialysis and lyophilization (preparation I) and further fractionation with ammonsulfate, using the fraction 20–50 % for isolation (preparation II). The arabinoxylan isolation is carried out using extraction of rye bran in 80 % ethanol (80 °C), centrifugation, aqueous extraction of the sediment, dialysis and lyophilization (preparation I). The further purification using the precipitate of the fraction 20–50 % leads to preparation II. The α-amylase inhibitor preparation II and the arabinoxylan preparation II were applied in a diet containing wheat starch and casein and fed to diabetic and healthy rats (Levis and Wistar). The postprandial increase of glucose was determined. It was detected that the postprandial increase of glucose is influenced neither by the α-amylase inhibitor nor by the soluble arabinoxylan in comparison to the control experiments. However, the α-amylase inhibitor of wheat significantly decreases the postprandial increase of glucose. The application of a test meal with α-amylase inhibitor of rye to health and diabetic of type-II-volunteers showed no variation of the blood glucose values. The reduction of the increase of glucose by the soluble β-glucan of oat cannot be confirmed for the soluble arabinoxylan of rye. We conclude that the effect of the α-amylase inhibitor as well as the soluble pentosan or glucan has to be examined for each cereal species.
    Notes: Zusammenfassung Aus Roggenmehl und Roggenkleie der Sorte „Clou“ werden der Protein-Inhibitor der α-Amylase und das lösliche Arabinoxylan isoliert. Die Anreicherung des α-Amylase-Inhibitors erfolgt durch Extraktion von Roggenmehl in wässriger CaCl2-Lösung (2 × 10−3M) unter Zusatz des Hemizellulasepräparates Veron HE (2 g/100 g Mehl), anschließende Dialyse und Lyophilisierung (Präparat I). Durch weitere Ammonsulfatfraktionierung und Aufarbeitung der Fraktion 20–50 % Sättigung wird Präparat II gewonnen. Das Arabinoxylanpräparat wird durch Extraktion von Roggenkleie in 80 % Ethanol bei 80 °C, Zentrifugation, wässrige Extraktion des Sedimentes, Dialyse und Lyophilisation gewonnen (Präparat I). Aus dem Extrakt wird Präparat II durch Ethanolfraktionierung und Aufarbeitung der Fraktion 20–50 % isoliert. Das durch Ammonsulfatfraktionierung gereinigte α-Amylase-Inhibitor-Präparat und das durch Ethanolfraktionierung angereicherte Arabinoxylanpräparat werden mit einem Testfutter, bestehend aus Weizenstärke und Casein, an diabetische und stoffwechselgesunde Ratten appliziert und im Blut der postprandiale Glucoseanstieg bestimmt. Es wird nachgewiesen, daß dieser sowohl durch den Inhibitor als auch durch das lösliche Arabinoxylan des Roggens im Vergleich zur Kontrolle nicht beeinflußt wird. Dagegen führte der α-Amylase-Inhibitor des Weizens zu einer signifikanten Verminderung des Glucoseanstiegs. Nach Verzehr einer Testmahlzeit mit zugesetztem α-Amylase-Inhibitor aus Roggen durch Stoffwechselgesunde und Typ-II-Diabetiker kann ebenfalls keine Veränderung der Blutglucosewerte nachgewiesen werden. Somit läßt sich die Senkung des Glucoseanstiegs durch das lösliche β-Glucan aus Hafer mit dem löslichen Arabinoxylan des Roggens nicht bestätigen. Daraus ergibt sich sowohl beim α-Amylase-Inhibitor als auch beim löslichen Pentosan/Glucan die Notwendigkeit, die Wirksamkeit bei jeder Getreideart zu prüfen.
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    European journal of nutrition 35 (1996), S. 235-240 
    ISSN: 1436-6215
    Keywords: Trans fatty acids ; arachidonic acid ; children ; diet ; trans-Fettsäuren ; Arachidonsäure ; Kinder ; Ernährung
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
    Description / Table of Contents: Zusammenfassung Da nachteilige Folgen der Aufnahme von trans-Fettsäuren auf den Lipoproteinstoffwechsel und die Arachidonsäuresynthese bei Kindern befürchtet werden, untersuchten wir den trans-Gehalt in verschiedenen Brotaufstrichen und Brotbelägen, die bevorzugt von Kindern verzehrt werden. Dabei fanden sich die höchsten Gehalte in regulären Margarinen: (4,5; 0,0–10,6; Median der Gewichts-% der Fettsäuren, Minimum-Maximum), Nuß-Nougat-Cremes (5,5; 0,7–11,1 %), Butter 4,7; 3,7–5,2) und Käse (3,6; 1,8–4,0), während Diätmargarinen (0,2; 0,0–0,4), vegetarische Brotaufstriche (0,2; 0,1–0,4), Erdnußbutter (0,0; 0,0–0,3) und Wurst (1,7; 0, 6–6,4) niedrigere Gehalte aufwiesen. Die unterschiedlichen Gehalte führen zu Unterschieden in der aus Diätplänen berechneten täglichen trans-Aufnahme von 〉100 % (3,1 g/d vs. 1,5 g/d) bei 4–7jährigen Kindern. Es erscheint uns sinnvoll, den trans-Fettsäuregehalt von fettreichen Lebensmitteln zu deklarieren, um dem Verbraucher eine gezielte Auswahl zu ermöglichen, und eine Minderung der Bildung von trans-Fettsäuren bei der technischen Fetthärtung anzustreben.
    Notes: Summary A high intake of trans fatty acids in children may be disadvantageous because of untoward effects on lipoprotein metabolism and a possible impairment of arachidonic acid synthesis. We measured the trans fatty acid content of different brands of spreads and cold cuts typically consumed by German children because these foods may contribute a considerable portion of total trans fatty acid intake. The highest trans fatty acid contents were found in regular margarines (4.5, 0.0–10.6; median %-wt/wt of fatty acids, minimal-maximal), chocolate spreads (5.5, 0.7–11.1), butter (4.7, 3.7–5.2) and cheese (3.6, 1.8–4.0), while lower values were present in diet margarines (0.2, 0.0–0.4), vegetarian spreads (0.2, 0.1–0.4), peanut butter (0.0, 0.0–0.3) and sausages (1.7, 0.6–6.4). Calculations of typical dietary plans for young children show that food selection and variations in trans fatt acid contents may lead to marked differences in daily trans intake of 〉100 % (3.1 g/d vs. 1.5 g/d). We propose that trans fatty acid content should be declared on labels of fatty food products to enable the consumer to choose, and further attempts should be made to lower trans fatty acid formation during technical hydrogenation.
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  • 67
    ISSN: 1436-6215
    Keywords: Fatty liver ; isomeric octadecenoic acids ; oleic acid ; petroselinic acid ; coriander oil ; Fettleber ; Isomere Octadecensäuren ; Ölsäure ; Petroselinsäure ; Korianderöl
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
    Description / Table of Contents: Zusammenfassung In verschiedenen Studien wird eine günstige Wirkung von Pflanzenölen mit hohem Anteil an einfach ungesättigten Fettsäuren, z.B. Ölsäure (cis-9-Octadecensäure), auf die Gesundheit beschrieben. Kürzlich haben wir gezeigt, daß die Fütterung von Ratten mit Korianderöl, das hohe Anteile eines Positionsisomers der Ölsäure enthält, nämlich Petroselinsäure (cis-6-Octadecensäure), zu einer signifikanten Erniedrigung der Arachidonsäure (allcis-5,8,11,14-Eicosatetraensäure)-Anteile in den zellulären Lipiden führte. Hier berichten wir über histopathologische Befunde an männlichen Wistar-Ratten, denen isokalorische Diäten mit 2 % Maiskeimöl und jeweils 12 % (w/w) Pflanzenöl (ölsäure-reiches oder konventionelles Sonnenblumenöl, Olivenöl, Rapsöl, Korianderöl) und unterschiedlichen Anteilen an isomeren Monoenfettsäuren, d.h. Öl- und Petroselinsäure, verabreicht wurden. Die Tiere der Kontrollgruppe erhielten eine Standarddiät mit 4 % (w/w) Fett. Leber, Herz, Aorta, Magen und Milz wurden anatomisch und histologisch untersucht. Die Lebern der Tiere aller Gruppen, die eine fettreiche Diät erhalten hatten — mit Ausnahme der Korianderöl-Gruppe —, entwickelten eine mäßige, nicht-degenerative Fettinfiltration der Hepatocyten, die in den Periportalfeldern einsetzte. Eine ausgeprägte bis schwere Fettinfiltration wurde dagegen in den Hepatocyten von Tieren gefunden, die mit petroselinsäurereichem Korianderöl gefüttert worden waren. In dieser experimentellen Gruppe enthielten die Lebern Fettzysten und Lipidvesikel unterschiedlicher Größe. Außerdem wurden vergrößerte Kerne in zahlreichen Hepatocyten beobachtet, die keine Fettinfiltration aufwiesen. In Ratten, die mit einer Standarddiät gefüttert worden waren, wurde dagegen keine Fettinfiltration in den Leberzellen gefunden. Die Zellen aller anderen untersuchten Organe und Gewebe, insbesondere Herz und Aorta, zeigten weder nicht-degenerative Fettinfiltrationen noch irgendwelche anderen degenerativen Veränderungen. Unsere Ergebnisse zeigen, daß die Fütterung fettreicher Diäten mit unterschiedlichen C18 cis-Monoenfettsäuren in Abhängigkeit von der Position der Doppelbindung unterschiedliche histopathologische Veränderungen in der Leber von Ratten hervorruft. Während Pflanzenöle mit variierenden Ölsäureanteilen ausschließlich zu mäßigen Fettinfiltrationen in den Hepatocyten führten, wurden in den Lebern der mit petroselinsäurereichem Korianderöl gefütterten Tiere degenerative Veränderungen (Fettzysten) sowie — in einigen Fällen — vergrößerte Zellkerne beobachtet, die auf eine unspezifische Stimulierung der Hepatocyten hindeuten.
    Notes: Summary Beneficial effects on health parameters by ingestion of plant oils having high levels of monounsaturated fatty acids such as oleic (cis-9-octadecenoic) acid have been described in several studies. Recently, we have shown that feeding of coriander oil containing high proportions of a positional isomer of oleic acid, i.e. petroselinic (cis-6-octadecenoic) acid, led to significantly decreasing proportions of arachidonic (allcis-5,8,11,14-eicosatetraenoic) acid in the cellular lipids. Here, we report histopathological findings in male Wistar rats fed isocaloric diets containing 2 % corn oil and 12 % (w/w), each, of different plant oils (high-oleic and conventional sunflower oil, olive oil, rapeseed oil as well as coriander oil) containing varying levels of monounsaturated fatty acids, i.e. oleic or petroselinic acids. One group of animals was fed a standard diet containing 4 % (w/w) of fat as control. Liver, heart, aorta, stomach, and spleen were anatomically and histologically examined. Livers of animals from all the groups that had received high-fat diets — except the coriander oil group — showed moderate non-degenerative fat infiltrations of the hepatocytes beginning in the periportal fields. Marked to severe fat infiltration was observed in hepatocytes of animals fed coriander oil. In this experimental group the livers were found to contain fatty cysts in addition to hepatocytes with mixed-size lipid vesicles. Moreover, enlarged nuclei were observed in numerous hepatocytes without fat infiltration. Fat infiltration was not observed in livers of animals fed a rat standard diet. In the cells of all other organs and tissues studied, in particular heart and aorta, neither non-degenerative fat infiltrations nor other degenerative changes were observed for any group. Our results show that feeding of fat-rich diets containing varying proportions of C18 cis-monoenoic fatty acids induced different histopathological alterations in the livers of rats, depending on position of the double bond. Plant oils containing varying proportions of oleic acid lead exclusively to moderate fat infiltration in the hepatocytes, whereas in the animals fed high-petroselinic coriander oil degenerative alterations (fatty cysts) as well as — in several cases — enlarged nuclei were found that are likely due to a non-specific stimulation of the hepatocytes resulting from the cell degeneration observed.
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  • 68
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    European journal of nutrition 35 (1996), S. 259-265 
    ISSN: 1436-6215
    Keywords: Diet ; serum cholesterol ; serum triglycerides ; HDL-cholesterol ; LDL-cholesterol ; Apo B ; hyperlipoproteinaemia ; nonsmokers ; Diät ; Cholesterinspiegel ; Serumtriglyceride ; HDL-Cholesterin ; LDL-Cholesterin ; Apo B ; Hyperlipoproteinämie ; Nichtraucher
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
    Description / Table of Contents: Zusammenfassung Die Absicht dieser Studie war es, die Prävalenz der veränderten Serumspiegel von Lipiden, Lipoproteinen und Apolipoproteinen (Apo) B bei 169 spanischen, männlichen, sehr aktiven Nichtrauchern im Alter von 20 bis 65 Jahren, die Sonnenblumenöl verzehren, zu erforschen. Die Serumwerte, die für Cholesterin (TC), Triglyceride (TG), LDL-Cholesterin und für den TC/HDL-Cholesterin-Quotient erhalten wurden, waren altersbedingt unterschiedlich. Ein detailliertes Ernährungsprotokoll über einen Zeitraum von 12 Tagen zeigte, daß die Diät der Probanden typisch mediterran war, mit der Ausnahme des Verzehrs von Sonnenblumenöl — statt Olivenöl. Der Beitrag von gesättigten, einfach-und mehrfach ungesättigten Fettsäuren zur gesamten Kcal-Aufnahme war je 9,9 %, 12,7 % und 8,8 %. Der Index Cholesterin/gesättigtem Fett in der Diät betrug im Mittel 19,2 per 1 000 Kcal, während der Keys-Index der Diät 27,1 war. Die tägliche Aufnahme an Ballaststoffen, Ascorbinsäure und Vitamin E betrug jeweils 25,1 g, 89,6 mg und 28,3 mg. Der Kalzium/Magnesium-Quotient betrug 1,54. Der niedrige Anteil an Männern mit hohem Cholesterinspiegel (5,4 % mit TC ≥6,49 mmol/L), hohen TG-Werten (3,7 % mit TG ≥2,25 mmol/L), hohen Apo B-Werten (3,0 % mit ≥1,5 g/L), niedrigen HDL-Cholesterin-Werten (0,7 % mit ≤0,91 mmol/L), hohen LDL-Cholesterin-Werten (1,4 % mit ≥4,94 mmol/L) oder mit einem hohen Wert des TC/HDL-Cholesterin-Quotienten (2,8 % mit ≥5,0) läßt einen ausreichenden Schutz gegen zukünftige koronare Herzleiden erwarten.
    Notes: Summary The aim of this study was to assess the prevalence of altered levels of serum lipids, lipoproteins and apolipoprotein (Apo) B in very active, 20 to 65 year-old, Spanish male nonsmokers who consumed sunflower oil. Among the 169 participants, total serum cholesterol (TC), triglycerides (TG), LDL-C, and TC/HDL-C were found to be age-dependent variables. A detailed study over a 12-day period showed that this population displayed a Mediterranean dietary pattern, with the exception of the substitution of sunflower for olive oil. Saturated, monounsaturated and polyunsaturated fatty acids represented 9.9 %, 12.7 % and 8.8 % of the total amount of energy, respectively. The cholesterol-saturated fat index of the average diet was 19.2 per 1 000 kcal, whereas the Keys index of the diet was 27.1. Daily intakes of fibre, ascorbic acid and vitamin E were 25.1 g, 89.6 mg and 28.3 mg, respectively. The calcium/magnesium ratio of the average diet was 1.54. The low percentage of individuals with high TC levels (5.4 % with TC ≥6.49 mmol/L), high TG levels (3.7 % with TG ≥2.25 mmol/L), high Apo B levels (3.0 % with ≥1.5 g/L), low levels of HDL-C (0.7 % with ≤0.91 mmol/L), high LDL-C levels (1.4 % with ≥4.94 mmol/L or a high TC/HDL-C ratio (2.8 % with ≥5.0) suggest a reasonable protection against coronary heart disease in this Spanish population.
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  • 69
    ISSN: 1436-6215
    Keywords: Vitamin B6 ; Gravidität ; Laktation ; Ratten ; Aspartat-Aminotransferase ; Alanin-Aminotransferase ; Vitamin B6 ; gravidity ; lactation ; rats ; aspartate-aminotransferase ; alanin-aminotransferase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
    Description / Table of Contents: Summary Eighty female Sprague-Dawley rats weighing 257 g were fed during gravidity a semi-synthetic diet containing five vitamin-B6-treatment groups (0.6, 3, 6, 18 and 180 mg/kg diet). The daily food intake was 14 g. During the following lactation the rats of each treatment group were divided into two groups containing 3 and 6 mg vitamin B6. At the 14th day of lactation the dams were decapitated. Parameters for determination of the vitamin-B6-status were activity of AST and ALT in plasma, erythrocytes and liver. The average activity of AST in plasma was 549 U/l, in erythrocytes 1 939 U/l and liver 106 U/g fresh matter (FM). The increasing vitamin-B6-supplementation during gravidity resulted in an elevated activity of AST between lowest and highest treatment group in plasma 56 %, erythrocytes 44 %, and in liver 43 %, respectively. In response to the increasing vitamin-B6-treatment during lactation the activity of AST in plasma increased for 19 %, in erythrocytes for 13 %, and in liver for 24 %, respectively. A low vitamin-B6-supply (0.6 mg/kg diet) during gravidity in combination with demand-oriented supply during lactation (6 mg/kg diet) initiated the highest increase of activity. A deficient vitamin-B6-supply during lactation (3 mg/kg diet) could be compensated with optimal vitamin-B6-supply during gravidity. The values of ALT-activity showed no significant differences between the graded vitamin-B6-supplements, as a result of a high coenzyme saturation.
    Notes: Zusammenfassung 80 weibliche Sprague-Dawley-Ratten mit einem mittleren Deckgewicht von 257 g erhielten während der Gravidität eine semisynthetische Diät mit fünf verschiedenen Vitamin-B6-Zulagestufen von 0,6; 3; 6; 18 und 180 mg/kg Diät. Die tägliche Futtermenge betrug 14 g pro Tier. Mit Beginn der Laktation wurden die Tiere jeder Zulagestufe auf die zwei Zulagestufen 3 mg und 6 mg Vitamin B6/kg Diät verteilt und das Futter ad libitum angeboten. Am 14. Tag der Laktation wurden die Tiere dekapitiert. Der Vitamin-B6-Status der Ratten wurde anhand der Aktivitäten der Aspartat-Amino-transferase (AST) und der Alanin-Aminotransferase (ALT) im Plasma, den Erythrozyten und der Leber bestimmt. Die Aktivität der AST im Plasma am 14. Tag der Laktation lag im Durchschnitt bei 549 U/l, in den Erythrozyten bei 1 939 U/l und in der Leber bei 106 U/g FM. Die ansteigenden Vitamin-B6-Zulagen während der Gravidität verursachten im Plasma zwischen der geringsten und der höchsten Zulage eine Erhöhung der Aktivität um 56 %, in den Erythrozyten um 4 % und in der Leber um 43 %. Die Erhöhung der Vitamin-B6-Zulage während der anschließenden Laktation bewirkte eine Zunahme im Plasma im Mittel um 19 %, in den Erythrozyten um 13 % und in der Leber um 24 %. Überproportionale Aktivitätserhöhungen ergaben sich bei einer defizitären Zulage (0,6 mg Vitamin B6/kg Diät) während der Gravidität und anschließend bedarfsgerechter Versorgung (6 mg Vitamin B6/kg Diät) während der Laktation. Eine suboptimale Vitamin-B6-Versorgung (3 mg Vitamin B6/kg Diät) während der Laktation konnte durch vorangegangene bedarfsgerechte Versorgung während der Gravidität ausgeglichen werden. Die Ergebnisse der Aktivitätsmessungen der ALT zeigten keine signifikanten Einflüsse der alimentären Vitamin-B6-Versorgung, was durch eine höhere Coenzymabsättigung erklärt werden kann.
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  • 70
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    European journal of nutrition 35 (1996), S. 302-305 
    ISSN: 1436-6215
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
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  • 71
    ISSN: 1436-6215
    Keywords: Thiamin ; Riboflavin ; Pantothensäure ; praecaecale Verdaulichkeit ; Verfügbarkeit ; Ileorectalanastomose ; Thiamin ; riboflavin ; pantothenic acid ; precaecal digestibility ; availability ; ileorectalanastomosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
    Description / Table of Contents: Summary The aim of the present investigations was to produce results about precaecal digestibility of naturally occurring thiamin, riboflavin and pantothenic acid from corn, wheat bran and dried skimmilk. Precaecal digestibility is used as a quantitative measure for availability and was determined in ileorectomized growing pigs. Therefore, 6 female DL-pigs with a liveweight of about 30 kg were fitted with ileorectalanastomosis as end-to-side-anastomosis with preserved ileo-caeco-colic valve. The metabolism trials to collect the chymus quantitatively with these animals were carried out from the third week until 9 weeks after surgery in the liveweight range of about 40–70 kg. Precaecal digestibilities from corn, wheat bran and dried skimmilk were for thiamin 87, 91 and 96 %, respectively, with all values being significantly different. Riboflavin was 67, 62 and 94 % precaecally digestible, the significantly different values for pantothenic ranged from 20 to 47 and 90 %. “Availability” of native thiamin was higher than of riboflavin and pantothenic acid, which showed the lowest value of about 50 %. The availability of the vitamins from the animal product was significantly higher than from vegetable products. The suitability of the method is discussed.
    Notes: Zusammenfassung Die vorliegenden Untersuchungen dienten dazu, Ergebnisse zur praecaecalen Verdaulichkeit von nativem Thiamin, Riboflavin und Pantothensäure aus Mais, Weizenkleie und Magermilchpulver zu liefern. Die praecaecale Verdaulichkeit, als quantitatives Maß für die Verfügbarkeit, wurde an ileorectostomierten Schweinen ermittelt. Dazu wurden bei 6 wachsenden weiblichen DL-Schweinen beim Lebendgewicht von etwa 30 kg auf chirurgischem Weg Ileorectalanatomosen in Form der End-zu-Seit-Anastomosen mit Erhalt der Ileocaecalklappe hergestellt. Die Stoffwechselversuche mit quantitativer Chymussammlung wurden ab etwa der 3. Woche bis 9 Wochen nach der Operation im Gewichtsbereich der Tiere von 40–70 kg durchgeführt. Die praecaecale Verdaulichkeit aus Mais, Weizenkleie und Magermilchpulver betrug für Thiamin 87 %, 91 % und 96 % (jeweils signifikant verschieden), für Riboflavin 67, 62 und 94 % und für Pantothensäure 20, 47 und 90 %. Damit war die „Verfügbarkeit“ von natürlichem Thiamin deutlich höher als von Riboflavin; Pantothensäure wies mit etwa 50 % den signifikant schlechtesten Wert auf. Das tierische Produkt stellte im Vergleich zu den pflanzlichen Komponenten die Vitamine deutlich am besten zur Verfügung. Die Eignung der Methodik für Verfügbarkeitsstudien wird diskutiert.
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  • 72
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    European journal of nutrition 36 (1997), S. 1-2 
    ISSN: 1436-6215
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
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  • 73
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    European journal of nutrition 36 (1997), S. 28-29 
    ISSN: 1436-6215
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
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  • 74
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    European journal of nutrition 36 (1997), S. 30-30 
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    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
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  • 75
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    European journal of nutrition 36 (1997), S. 23-27 
    ISSN: 1436-6215
    Keywords: Vitamin E ; Fleisch ; Fettgewebe ; Leber ; Eigelb ; Vitamin E ; meat ; adipose tissue ; liver ; egg yolk
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
    Description / Table of Contents: Summary The α-tocopherol content of different meat cuts was examined. Chicken thigh had the highest vitamin E content, followed by chicken breast and pork shoulder (p〈0.05). The lowest concentrations were found in longissimus dorsi muscle from pork, beef, veal and in beef shoulder. Considering the average daily lean meat consumption (105 g) in Switzerland, recommendation for daily vitamin E intake was met to 3 %. Supplementation of 200 mg α-tocopherol acetate/kg feed to pigs and laying hens significantly increased the α-tocopherol content in all examined products. The α-tocopherol accumulation differed according to the following ranking: egg yolk 〉 liver 〉 adipose tissue 〉 musculus longissimus dorsi. The α-tocopherol:energy ratios were 28.8, 7.3, 0.9 and 1.2 mg/MJ for egg yolk, liver, adipose tissue and longissimus dorsi muscle of the vitamin E supplemented groups, respectively. The results showed that meat, with the exception of chicken thigh, is not an important supplier of vitamin E, not even from animals fed a vitamin E enriched diet. Egg yolk became a good source of vitamin E for human nutrition by dietary modification.
    Notes: Zusammenfassung In der vorliegenden Studie wurde der α-Tocopherolgehalt verschiedener Fleischstücke untersucht. Hähnchenschenkel hatte den höchsten α-Tocopherolgehalt, gefolgt von Hähnchenbrust und Schweineschulter (p〈0.05). Die niedrigsten Konzentrationen wurden im Musculus longissimus dorsi vom Schwein, Rind, Kalb und in der Rindsschulter nachgewiesen. Mit dem durchschnittlichen, täglichen Verzehr an magerem Fleisch (105 g) in der Schweiz wurden die Empfehlungen für die tägliche Vitamin E-Zufuhr zu 3 % gedeckt. Die Supplementierung des Schweine- und Legehennenfutters mit 200 mg α-Tocopherolacetat/kg führte zu einem signifikanten Anstieg des α-Tocopherolgehaltes in allen untersuchten Produkten. Die α-Tocopherolakkumulierung unterschied sich gemäß folgender Rangordnung: Eigelb 〉 Leber 〉 Fettgewebe 〉Musculus longissimus dorsi. Die Nährstoffdichten betrugen 28.8, 7.3, 0.9 und 1.2 mg α-Tocopherol/MJ für Eigelb, Leber, Fettgewebe und Musculus longissimus dorsi der jeweiligen mit Vitamin E supplementierten Gruppe. Diese Ergebnisse zeigen, daß Fleisch, mit Ausnahme des Hähnchenschenkels, von Tieren mit supplementierten Diäten kein bedeutender Vitamin E-Lieferant ist. Hingegen wurde Eigelb durch fütterungsbedingte Modifikation zu einer guten Vitamin E-Quelle.
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  • 76
    ISSN: 1436-6215
    Keywords: Thermogenesis ; α2-adrenergic activity ; ATP-sensitive K+ channels ; Thermogenese ; α2-adrenerge Aktivität ; ATP-sensitive K+ Kanäle
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
    Description / Table of Contents: Zusammenfassung Um den α2-adrenergen Einfluß auf die Wärmeproduktion (WP) zu untersuchen, wurden Jungbullen Umgebungstemperaturen von 4°C und 18° sowie Ernährungsintensitäten des 1,0 und 1,6-fachen des energetischen Erhaltungsbedarfs (MEm) ausgesetzt und präprandial der α2-adrenerge Agonist Clonidin verabreicht. Die präprandiale WP fiel nach Clonidingabe stark ab, am stärksten bei Tieren, die 4°C (1,6-fache des MEm) ausgesetzt waren. Die postprandiale WP stieg 5 h nach der Clonidininfusion bei diesen Tieren um das 1,3-fache der WP bei Verabreichung von physiologischer Salzlösung, während Tiere bei 18°C und 1,6-fachem an MEm nicht signifikant reagierten. Die WP-Stufen in den Umweltvarianten korrelierten nur schwach mit den Spiegeln an Glukose, freien Fettsäuren, Schilddrüsenhormonen und Kortisol, jedoch direkt und eng mit der Expression von Sulfonylharnstoffrezeptoren bei Monozyten. Die Ergebnisse zeigen, daß die WP maßgeblich von der α2-adrenergen Aktivität abhängt und deren regulatorische Funktion auch auf die Expression von Sulfonylharnstoff-rezeptoren gerichtet zu sein scheint.
    Notes: Summary To investigate the α2-adrenergic effect on the metabolic rate, young bulls were exposed to environmental variants (feeding levels of 1.0 and 1.6 times the MEm and ambient temperatures of 18°C and 4°C) and treated preprandially with a α2-adrenergic agonist (clonidine) in each case. The heat production (HP) was continuously measured by indirect calorimetry using climatized respiratory chambers. Post-clonidine, the preprandial HP fell in all variants but the strongest decrease occurred at 4°C, 1.6 times the MEm. The postprandial HP rose 1.3-fold the HP of animals received the carrier (saline) at 4°C, 1.6 times the MEm. Animals exposed to 18°C, 1.6-fold the MEm did not significantly increase the postprandial HP after clonidine administration, suggesting different sympathetic outflow corresponded to differing resting metabolic rate, occurring in the environmental variants. Circulating fuels (glucose, non-esterified fatty acids) responded to α2-adrenergic reduction of the sympathetic outflow but did not parallel the HP changes. Studies on monocytes revealed a linear correlation (r2〉0.9) between resting metabolic rate and expression of sulfonylurea receptors, the constitutive component of ATP-sensitive K+ channels (KATP) suggesting a function of KATP in coupling the systemic HP with cellular metabolism.
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  • 77
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    European journal of nutrition 36 (1997), S. 299-302 
    ISSN: 1436-6215
    Keywords: Energy retention ; protein retention ; fat retention ; growth ; body composition ; broilers ; Energieansatz ; Proteinansatz ; Fettansatz ; Wachstum ; Körperzusammensetzung ; Broiler
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
    Description / Table of Contents: Zusammenfassung Mit steigender Aufnahme erhöht sich der Körperfettgehalt und der Körperproteingehalt nimmt ab. Es wird oft angenommen, daß jede Zunahme im Ansatz mit mehr Fett und weniger Protein verbunden ist. Experimentelle Ergebnisse widerlegen jedoch diese Annahme. In zwei Experimenten mit männlichen Broilerhühnern wurden die Tiere auf einem Niveau von 60 % und 100 % der empfohlenen Energieaufnahme gefüttert. Die Körperzusammensetzung bei 1500 g zeigte, wie erwartet, daß sich bei steigenden Aufnahmen der Körperfettgchalt vergrößert und der Körperproteingehalt abnimmt. Fettund Proteinansatz waren linear mit der totalen Energieretention (ER) korreliert. Das bedeutet, daß jede Zunahme im Ansatz den gleichen Protein- und Fettgehalt besitzt. Wenn der Fettansatz gleich Null ist wird nur Protein, etwa 50 % des maximalen Ansatzes, retiniert. Wenn ER=O ist, wird Protein angesetzt und Fett mobilisiert. Energie-und N-Bilanzuntersuchungen bestätigen die konstante Zusammensetzung jeder Vergrößerung des Ansatzes. Die Ergebnisse beider Experimente zeigen, daß die ER aus zwei Komponenten besteht: einem basalen konstanten täglichen Proteinansatz und einer variablen zusätzlichen ER, die hauptsächlich aus Fett besteht. Der basale Proteinansatz beträgt etwa 50 % des maximalen Ansatzes. Mit steigenden Energieaufnahmen wird der basale Proteinansatz mit einer zusätzlichen Menge von Protein und Fett im konstanten Verhältnis ergänzt.
    Notes: Summary With increasing intakes the body fat content increases and that of protein decreases. It is most often assumed that this is brought about because each increment in retention contains more fat and less protein. Experimental results, however, showed that this explanation is not true. In two experiments male broiler chickens were fed at levels between 60 and 100 % of recommended energy intake. Body composition at 1500 g showed, as expected, that with increasing intakes body fat content increased and protein content decreased. Both fat and protein retention per day were linearly related to total energy retention (ER). This means that each increment in retention has the same protein and fat content. At zero fat retention only protein was retained, about 50 % of maximal retention. At zero ER protein was retained and fat mobilized. Energy and N balance experiments confirmed the constant composition of each increment in retention. The results of both experiments show that total ER consisted of two components: a basic constant daily protein retention and a variable additional ER, mainly consisting of fat. The basic protein retention is about half of maximal retention. With increasing energy intakes the basic protein retention is combined with an additional amount of protein and fat in a constant ratio.
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  • 78
    ISSN: 1436-6215
    Keywords: D2 18Omethod ; indirect calorimetry ; energy metabolism ; obesity ; D2 18O-Methode ; indirekte Kalorimetrie ; Energiemetabolismus ; Übergewicht
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
    Description / Table of Contents: Zusammenfassung Für die Bestimmung des Gesamtenergieumsatzes wurde eine neuartige2H/1H-und18O/16O-Äquilibriereinheit getestet, optimiert und eingesetzt. Es konnte gezeigt werden, daß übergewichtige Frauen und Männer, verglichen mit schlanken Probanden, sowohl erhöhte Ruhe-Nüchternumsätze, als auch erhöhte Gesamtenergieumsätze aufweisen. Der physical activity level (PAL)-Index weist tendenziell eine Verminderung auf, was eine erniedrigte physische Aktivität bei Übergewichtigen vermuten läßt.
    Notes: Summary A new2H/1H and18O/16O equilibration device was tested, standardized and employed for the determination of total energy expenditure. It was shown that overweight men and women have increased resting metabolic rate as well as increased total energy expenditure when compared to their lean counterparts. The physical activity level (PAL)index was slightly decreased which possibly suggests a decreased physical activity in obese people.
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  • 79
    ISSN: 1436-6215
    Keywords: Indirect calorimetry ; substrate oxidation ; feeding level ; fat mobilization ; Indirekte Kalorimetrie ; Substratoxidation ; Fütterungsniveau ; Fettmobilisierung
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
    Description / Table of Contents: Zusammenfassung Bei Nerzen (6 Kontrollitere (Gruppe I) und 12 reichlich gefütterten weiblichen Tieren (Gruppe II) wurde die Nährstoffoxidation aus Respirationsmessungen berechnet. Die Gaswechselmessungen erfolgten in 6 aufeinanderfolgenden einwöchigen Versuchsperioden. Die Energieversorgung für die Gruppe I und II betrug in der Periode 1 und 6 ca. 850 kJ ME/d, während der Restriktion und der Fütterung auf hohem Niveau betrug sie 450 bzw. 1300 kJ ME/d. Während der gesamten Versuchsperiode war die Energieaufnahme für beide Gruppen vergleichbar. Es gab aber signifikante Unterschieded zwischen den Perioden bei der Gruppe II. Die Mittelwerte der Protein-, Kohlenhydrat-und Fettoxidation betrugen 39%, 38% und 21% von der totalen Wärmeproduktion (WP) in der Gruppe I. Während der Restriktion betrug die Proteinoxidation bei der Gruppe II ca. 35% der WP. Während der ersten Periode der Fütterung auf hohem Niveau wuchs dieser Wert auf 55%. Während der Restriktion wurde eine hohe Fettoxidation gemessen, weil die Fettmobilisierung anstieg. Die Fettoxidation war niedrig, wenn die Futterzufuhr reichlich war. Es wird daraus geschlußfolgert, daß die Berechnungsmethode geeignete Aussagen liefert. Einige Nachteile der Methode werden diskutiert.
    Notes: Summary Nutrient oxidation was calculated from gas exchange measurements for 6 control and 12 flush fed female mink, measured in six consecutive, one week periods. The energy supply to controls and flushed animals in periods 1 and 6 was ca 850 kJ ME/day, and during restriction and flush feeding, it was ca 450 kJ ME/day and ca 1300 kJ ME/day, respectively. Over the total experimental period the energy intake was similar in both groups, but it differed significantly between periods in the flushed group. Protein, fat, and carbohydrate oxidation averaged 39, 38, and 21%, of the total heat production (HP), respectively in the control group. During restriction, protein oxidation was ca 35% of HP in flushed animals, then increasing to 55% of HP during the first period of refeeding. High values for fat oxidation were recorded during restriction because of fat mobilization and values were low when feed supply was ample. It was concluded that the calculation method was a good indicative method, but some short-comings were discussed.
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  • 80
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    European journal of nutrition 36 (1997), S. 326-326 
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    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
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  • 81
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    European journal of nutrition 36 (1997), S. 358-358 
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    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
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  • 82
    ISSN: 1436-6215
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
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  • 83
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    European journal of nutrition 38 (1999), S. 133-142 
    ISSN: 1436-6215
    Keywords: Key words Flavonoids – cancer-cell lines – proliferation –, cytotoxicity – apoptosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
    Notes: Summary Flavonoids are polyphenolic compounds that occur ubiquitously in foods of plant origin. Their proposed protective role in tumor development may prevail especially in the intestinal tract due to direct exposure of intestinal epithelia to these dietary ingredients. We have screened more than 30 flavonoids for their effects on cell proliferation and potential cytotoxicity in the human colon cancer cell lines Caco-2, displaying features of small intestinal epithelial cells, and HT-29, resembling colonic crypt cells. In addition, for selected compounds we assessed whether they induce apoptosis by determining caspase-3 activation. Studies on the dose dependent effects of the flavonoids showed antiproliferative activity of all compounds with EC50 values ranging between 39.7 ± 2.3 μM (baicalein) and 203.6 ± 15.5 μM (diosmin). In almost all cases, growth inhibition by the flavonoids occured in the absence of cytotoxicity. There was no obvious structure-activity relationship in the antiproliferative effects either on basis of the subclasses (i.e., isoflavones, flavones, flavonols, flavanones) or with respect to kind or position of substituents within a class. In a subset of experiments we examined the antiproliferative activities of the most potent compound of each flavonoid subgroup in addition in LLC-PK1, a renal tubular cell line, and the human breast cancer cell line MCF-7. Out of four flavonols tested, three displayed almost equal antiproliferative activities in all cell lines but fisetin was less potent in MCF-7 cells. The flavanones bavachinin and flavanone inhibited growth of Caco-2 and HT-29 cells with lower EC50 values than that obtained in LLC-PK1 and MCF-7 cells. The lower susceptibility of LLC-PK1 and MCF-7 cells towards growth arrest was even more pronounced in the case of the flavone baicalein. Half maximal growth-inhibition in LLC-PK1 and MCF-7 required 2.5 and 6.6 fold higher concentrations than that needed in the intestinal cell lines. The flavonoids failed to affect apoptosis in LLC-PK1 and MCF-7, whereas baicalein and myricetin were able to induce apoptosis in HT-29 and Caco-2 cells. In conclusion, flavonoids of the flavone, flavonol, flavanone, and isoflavone classes possess antiproliferative effects in different cancer cell lines. The capability of flavonoids for growth inhibition and induction of apoptosis can not be predicted on the basis of their chemical composition and structure.
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  • 84
    ISSN: 1436-6215
    Keywords: Key words Dietary fat – adipose tissue – lipolysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
    Notes: Abstract Variations in total energy intake and composition of daily food play an important role in the regulation of metabolic processes and so, in the control of body weight. This study was designed in order to investigate the effect of a high-fat diet on lipolysis in isolated adipocytes. For this purpose, fourteen Wistar rats were divided into two groups and fed either a standard-fat diet or a high-fat diet ad libitum for 7 weeks. Adipocytes were prepared from fat pads by collagenase digestion and incubated in vitro in the absence or presence of various lipolytic agents. Lipolysis was measured by the release of glycerol into the medium during 90 min of incubation. We observed that a high amount of fat in the diet induced an enlargement of adipose tissue, which was accompanied by a reduction of β-adrenergic agonist-induced lipolysis, that could be due to a loss of β1 and β3-adrenoceptor number or to alterations of their coupling to adenylate-cyclase through the guanine nucleotide regulatory protein. New data about regional differences were provided by comparing two adipose locations (subcutaneous and visceral).
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  • 85
    ISSN: 1436-6215
    Keywords: Key words Wine polyphenols – 8-hydroxy-2'-deoxyguanosine – oxidative damage – 2-nitropropane – 1,2-dimethylhydrazine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
    Notes: Summary Background: Flavonoids are polyphenolic antioxidants occuring in vegetables and fruits as well as beverages such as tea and wine which have been thought to influence oxidative damage. Aim of the study: We wanted to verify whether a complex mixture of wine tannins (wine complex polyphenols and tannins, WCPT) prevent chemically-induced oxidative DNA damage in vivo. Methods: Oxidative DNA damage was evaluated by measuring the ratio of 8-hydroxy-2'-deoxyguanosine (80HdG)/ 2-deoxyguanosine (2dG) × 10−6 in hydrolyzed DNA using HPLC coupled with electrochemical and UV detectors. Results: We treated rats with WCPT (57 mg/kg p.o.) for 14 d, a dose 10-fold higher than what a moderate wine drinker would be exposed to. WCPT administration significantly reduced the ratio of 80HdG/2dG × 10−6 in liver DNA obtained from rats treated with 2-nitropropane (2NP) relative to controls administered 2NP only (33.3 ± 2.5 vs. 44.9 ± 3.2 × 10−6 2dG; μ± SE; p〈0.05). On the contrary, pretreatment with WCPT for 10 d did not protect the colon mucosa from oxidative DNA damage induced by 1,2-dimethylhydrazine (DMH). 2NP and DMH are hepatic and colon carcinogens, respectively, capable of inducing oxidative DNA damage. Conclusions: WCPT have protective action against some types of chemically-induced oxidative DNA damage in vivo.
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  • 86
    ISSN: 1436-6215
    Keywords: Key words Anthocyanidins – anthocyanins – comet assay – antioxidative potential – oxidized DNA-bases
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
    Notes: Summary Anthocyanins are common colored plant flavonoids, occurring as glycosides of the respective anthocyanidin-chromophores. Like other flavonoids, anthocyanidins are also expected to have antioxidative and antimutagenic properties in vivo, although only few data are available. To gain more knowledge on possible protective mechanisms in mammalian cells, we have compared their extracellular and intracellular antioxidative potential in vitro and in human colon tumor cells. We used Aronia melanocarpa Elliot anthocyanin (AA) concentrates, fractions thereof, concentrates from Elderberry, Macqui, and Tintorera fruits, as well as pure compounds. In vitro, antioxidative properties of the samples were studied with the ferric reducing ability assay (FRA assay). As a measure of intracellular oxidative/antioxidative effects, H2O2-induced strand breaks as well as oxidized DNA bases were determined in human tumor HT29 clone 19A cells using a microgelelectrophoresis assay (comet test). Major results were that isolated compounds (aglycons and glycosides) and complex plant samples are powerful antioxidants in vitro. In fact their activities by far exceeded those of Trolox and vitamin C in the FRA assay. Also H2O2-induced DNA strand breaks were reduced in cells treated with the complex plant extracts. In contrast, endogenous generation of oxidized DNA bases was not prevented. In summary, the intracellular steady state of oxidized DNA bases is not altered by anthocyanins or anthocyanidins. This findings raises questions with respect to the cancer preventive potential of anthocyanidins within specific tissues, such as the colon. Extracellularly, however, the compounds are potent antioxidants. This points to their potential for providing systemic protection in vivo, e.g., by scavenging oxidants in the blood stream and in the colon. Notably, both aglycons and glycosides have equally strong antioxidant activity.
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  • 87
    ISSN: 1436-6215
    Keywords: Key words Estrone – estrogen – obesity – dietary estrogen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
    Notes: Summary Background Estrone is a relatively abundant hormone widely distributed in tissues of animal and plant origin. It is a mild estrogen that induces increases in body weigt in experimental animals. The relative abundance of estrone esters in animal tissues suggests that it may also be found in foods, from which it may alter the mechanisms of body weight control. Aim of the study To measure the total estrone content in food and to determine whether this may affect body weight. Methods In the first part of the study, a method was devised for the measurement of total estrone content in food. This was applied to the analysis of estrone content in a variety of food. Finally, hyperlipidic diets (18.6 MJ/kg) with a total estrone content 0.89 ± 0.21 μmol/kg (control group) and 1.37 ± 0.13 μmol/kg (laced with estrone fatty esters) were given to rats during 15 days, in order to determine the influence of dietary estrone on the body mass. Zucker lean (Fa/?) rats weighting initially 200–215 g were used. The total estrone (essentially as fatty esters) content of food was investigated by combining a dried methanol extraction with saponification and measurement of the free estrone evolved through radioimmunoassay. Result The content of estrone was zero in some vegetables, but significant in fruits, meats, and especially fats, both of plant and animal origin. The application of these analyses to a standard recommended diet for humans may result in intakes of more than 1 μmol of estrone per day, a figure comparable to the estrogen production by women. When rats were exposed to a raised estrone content in a fat-rich diet, they significantly increased their body weights, doubling their rate off growth (1.99 g/day) compared with controls (0.81 g/day), but maintaining their plasma composition and the proportions of lipid, water, and protein in their carcasses. Conclusion The widely distributed estrone esters in food and their relatively high concentrations may result in high free hormone intakes in humans. The continued and massive intake of estrone may enhance tissue deposition and lead to obesity.
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    European journal of nutrition 38 (1999), S. 295-296 
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    Source: Springer Online Journal Archives 1860-2000
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  • 89
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    European journal of nutrition 38 (1999), S. 286-292 
    ISSN: 1436-6215
    Keywords: Key words Plant oils – tocopherols – sister chromatid exchanges
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
    Notes: Summary Background: Plant fats and oils are major sources of mono- and polyunsaturated fatty acids as well as vitamin E, the major fat-soluble antioxidants in human nutrition. Dietary antioxidants are expected to reduce cancer risk by minimizing DNA damage. Aim of the study: To compare the effects of γ-tocopherol rich corn oil and the mixture of the α-tocopherol rich olive/sunflower oil on plasma concentration of tocopherols and on the frequency of sister chromatid exchange (SCE), an indicator of DNA damage. Methods: This study had a double-blind, cross-over design and was conducted in 20 normal healthy non-smoking males aged 19–31 years. Design included a 2-week adjustment period and two 2-week test periods in which diets containing 30% energy as fat including either 80 g of corn oil (CO) (20 mg α-tocopherol, 100 mg γtocopherol) or 80 g of olive/sunflower oil (OSO) (24 mg α-tocopherol, 2.4 mg γ-tocopherol) as the main fat-source, were given. Blood samples for analysis of SCE rate and content of tocopherols were collected at the beginning (T0), after adjustment (T1) and after the test period (T2) in intervals of 2 weeks. Results: After two weeks of the corn oil diet, the plasma concentration of γ-tocopherol increased but α-tocopherol decreased significantly compared to the olive/sunflower oil diet. The concentration of α-tocopherol increased (CO: 22.99 ± 1.11 vs. OSO: 24.40 ± 1.49 μmol/l) and that of γ-tocopherol decreased (CO: 4.19 ± 0.29 vs. OSO: 2.99 ± 0.25 μmol/l) after the olive/sunflower oil diet. Intake of the corn oil diet was associated with reduced SCE rate and intensity, whereas there was no change in SCE after the olive/sunflower oil diet (CO: 7.66 ± 0.25 vs. OSO: 8.06 ± 0.47 mean SCE/cell). Conclusions: The combination of γ-tocopherol with α-tocopherol in corn oil diet despite the lower α-tocopherol equivalents/diene acid equivalents ratio achieved better protection against DNA damage than α-tocopherol alone in the olive/sunflower oil diet.
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  • 90
    ISSN: 1436-6215
    Keywords: Sardinen ; Diäten mit Cholesterol bereichert ; Cholesterolspiegel ; Serumtriglyceride ; Olivenöl ; Sonnenblumenöl ; Fried sardines ; cholesterol-enriched diets ; serum cholesterol ; serum triglycerides ; olive oil ; sunflower oil
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
    Description / Table of Contents: Summary The effect of diets containing olive-oil-fried sardines (diet 1) or sunflower-oil-fried sardines (diet 3) upon the serum cholesterolraise induced by dietary cholesterol was studied after a 4-week experiment in growing Wistar rats. Results of diet 1 were compared to those obtained in diets containing casein plus olive oil (diet 2), whereas results of diet 3 were compared to those obtained with casein plus sunflower oil (diet 4). All diets contained cholesterol and bovine bile as a cholesterol-raising agent. The hypercholesterolemic effect of dietary cholesterol in fried-sardine groups (a total cholesterol (TC) increase of 0.9 mmol/L (p〈0.05 and 0.4 mmol/L (not significant) in groups 1 and 3, respectively) was markedly lower than in groups 2 and 4 (a TC increase of 13.9 mmol/L (p〈0.01) and 18.2 mmol/L (p〈0.01), respectively). Serum triglyceride levels decreased in fried-sardine diets (p〈0.05) while they increased in casein diets (p〈0.05). HDL-cholesterol levels appear lower in diet 1 than in diet 2 (p〈0.05), but similar in diets 3 and 4. However, HDL-fraction carries in diets 1, 2, 3 and 4, 13 %, 4 %, 53 % and 5 % of TC, respectively. Results showed that fried-sardine diets exert a powerful check effect on the cholesterol-raising effect induced by dietary cholesterol.
    Notes: Zusammenfassung In Versuchen von 4 Wochen Dauer wurde der Einfluß cholesterolangereicherter Diäten, die in Olivenöl (Diät 1) oder in Sonnenblumenöl (Diät 3) gebratene Sardinen enthielten, auf die Erhöhung des Cholesterolspiegels bei wachsenden Wistar Ratten untersucht. Die Ergebnisse von Diät 1 wurden mit denen von Diät 2 (Kasein plus Olivenöl) und die Resultate von Diät 3 mit denen von Diät 4 (Kasein plus Sonnenblumenöl) verglichen. Alle Diäten enthielten Cholesterol und Rindergalle als cholesterolerhöhende Agentien. Der hypercholesterolämische Effekt war in den Diäten mit den gebratenen Sardinen (eine Erhöhung des Cholesterolspiegels (TC) von je 0.9 mmol/L (p〈0.05) und 0.4 mmol/L (nicht signifikant) in den Gruppen 1 und 3) auffallend kleiner als in den Kontrollgruppen 2 und 4 mit Kasein (eine Erhöhung des TC von je 13.9 mmol/L (p〈0.01) und 18.2 mmol/L (p〈0.05)). Die Serumtriglyceride fielen bei Aufnahme der Sardinen (p〈0.05) und stiegen bei Aufnahme der Kasein-Diäten (p〈0.05). Das HDL-Cholesterolgehalt war niedriger mit Diät 1 als mit Diät 2 (p〈0.05) aber ähnlich bei den Diäten 3 und 4. Die HDL-Fraktion betrug in den Diäten 1, 2, 3 und 4 je 13 %, 4 %, 53 % und 5 % des TC. Diese Ergebnisse zeigen, daß Diäten mit gebratenen Sardinen eine große Hemmwirkung auf den cholesterolerhöhenden Effekt des Cholesterols haben.
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    European journal of nutrition 34 (1995), S. 277-283 
    ISSN: 1436-6215
    Keywords: Selen ; Glutathion-Peroxidase ; Schilddrüsenhormone ; Thyroxin ; Triiodthyronin ; Typ-I-Deiodase ; Selenium ; glutathione peroxidase ; thyroid hormones ; thyroxine ; triiodothyronine ; type-I-deiodinase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
    Description / Table of Contents: Summary In an experiment with 72 male weanling Sprague Dawley rats the effect of varying selenium intake on parameters of thyroid hormone metabolism was investigated. The animals were divided into 6 groups. One of the groups was fed a semi-synthetic diet based on casein which was poor in selenium (38 µg/kg). The other groups were fed the same diet supplemented with Na2SO3·5H2O to achieve a selenium concentration of 50, 100, 300, 600 and 3 000 µg/kg. The experiment lasted 40 days. Different selenium intake had no effect on food intake, weight gain, hematological and selected clinical-chemical parameters. Determination of glutathione peroxidase activity and selenium concentration of serum showed a selenium deficiency in animals fed the diet not supplemented with selenium. Serum T3 concentration and hepatic type-I-deiodinase activity were decreased in the group without selenium supplementation in contrast to the groups fed diets adequate in selenium (100, 300 µg/kg). A diet supplementation of 50 µg/kg already increased hepatic type-I-deiodinase activity to levels of the groups fed diets adequate in selenium. In groups supplemented with 600 and 3 000 µg/kg diet, serum T3 concentration was reduced by half of groups fed diets adequate in selenium. Supplementation with 3 000 µg Se/kg lowered the type-I-deiodinase activity in contrast to groups fed diets adequate in selenium, but not significantly. Serum concentrations of T4 and fT4 were not changed by various selenium intake. The results of this investigation show an alteration in thyroid hormone metabolism at low selenium intake as well as at high selenium intake.
    Notes: Zusammenfassung Die Auswirkungen einer unterschiedlichen Selenversorgung auf Parameter des Stoffwechsels der Schilddrüsenhormone sollten in einem Versuch mit 72 männlichen wachsenden Sprague Dawley Ratten untersucht werden. Die Tiere wurden in 6 Gruppen eingeteilt, wovon eine Gruppe eine selenarme halbsynthetische Diät auf Caseinbasis mit einem Se-Gehalt von 38 µg/kg erhielt. Die übrigen Gruppen erhielten die selbe Diät, die durch Zulage von Na2SO3·5H2O auf Selengehalte von 50, 100, 300, 600 und 3 000 µg/kg gebracht wurde. Die Versuchsdauer betrug 40 Tage. Die unterschiedliche Zufuhr von Selen hatte keinen Einfluß auf Futteraufnahme, Entwicklung der Lebendmasse, hämatologische und ausgewählte klinisch-chemische Parameter. Ein Selenmangel bei der Gruppe, die die nicht supplementierte Basisdiät erhalten hatte, konnte anhand der Aktivität der Glutathion-Peroxidase und der Selenkonzentration im Serum diagnostiziert werden. Beide Parameter stiegen ab einer Se-Zulage von 300 µg/kg noch an, allerdings geringfügig. Die Konzentration von T3 im Serum und die Aktivität der Typ-I-Deiodase in der Leber der Gruppe ohne Selenzulage war im Vergleich zu den bedarfsgerecht (100, 300 µg/kg) versorgten Gruppen vermindert. Bereits eine Selenzulage von 50 µg/kg Diät konnte die Aktivität der Typ-I-Deiodase auf die Werte der bedarfsgerecht versorgten Gruppen mit 100 und 300 µg Selenzulage anheben. Bei den Gruppen mit 600 und 3 000 µg/kg Diät Selenzulage war die Konzentration von T3 im Serum im Vergleich zu den bedarfsgerecht versorgten Gruppen auf etwa die Hälfte reduziert. Durch die Selenzulage von 3 000 µg/kg Diät war die Aktivität der Typ-I-Deiodase gegenüber den bedarfsgerecht versorgten Gruppen vermindert, die Verminderung war jedoch nicht statistisch signifikant. Die Konzentrationen von T4 und fT4 waren durch die unterschiedliche Selenzufuhr kaum verändert. Die Untersuchung zeigt insgesamt, daß sowohl unzureichende als auch über den Bedarf hinausgehende Selenzufuhr zu Veränderungen im Stoffwechsel der Schilddrüsenhormone führt.
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    European journal of nutrition 34 (1995), S. 1-1 
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    Source: Springer Online Journal Archives 1860-2000
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    European journal of nutrition 34 (1995), S. 30-31 
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    European journal of nutrition 34 (1995), S. 113-117 
    ISSN: 1436-6215
    Keywords: Blei ; Cadmium ; Quecksilber ; Gewürze ; Gewürzzubereitungen ; Wurstwaren ; Lead ; cadmium ; mercury ; spices ; condiments ; meat products
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
    Description / Table of Contents: Summary The lead and cadmium contents of 50 spices and 19 condiments were investigated by means of flameless atomic absorption spectrophotometry. Mercury contents were determined by cold vapor atomic absorption method including amalgamation. The mean concentrations of lead, cadmium, and mercury were 0.470 mg/kg, 0.080 mg/kg, and 0.005 mg/kg, respectively. By using the detected levels of these three heavy metals in model calculations only a small carry-over of lead, cadmium, and mercury in meat products by spices and condiments can be assumed.
    Notes: Zusammenfassung 50 Gewürze und 19 Gewürzzubereitungen wurden mittels flammenloser Atomabsorptionsspektrometrie auf ihren Blei- und Cadmiumgehalt sowie mittels Kaltdampftechnik und nachfolgender Amalgamierung auf ihren Quecksilbergehalt untersucht. Im Mittel wurden hierbei 0,470 mg Blei, 0,080 mg Cadmium und 0,005 mg Quecksilber pro kg Würzmittel gefunden. Anhand von Modellrechnungen wurde ein nur geringer Blei-, Cadmium- und Quecksilbereintrag über Würzmittel in die Wurstsorten Fleischwurst, Leberwurst und Mettwurst aufgezeigt.
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  • 95
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    European journal of nutrition 34 (1995), S. 137-142 
    ISSN: 1436-6215
    Keywords: Taurine ; plasma ; whole blood ; depletion ; supplementation ; Taurin ; Plasma ; Gesamtblut ; Taurinmangel ; Supplementation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
    Description / Table of Contents: Zusammenfassung Die vorliegende Studie untersuchte die Beziehung zwischen der Taurinkonzentration in Plasma und Gesamtblut unter normalen physiologischen Bedingungen bei Menschen und bei Katzen sowie nach oraler Taurinsupplementierung beim Menschen und nach taurinfreier Fütterung bei Katzen. Beim Menschen betrug die durchschnittliche Taurinkonzentration im Plasma 44±8 µmol/L und im Gesamtblut 222±35 µmol/L. Unter diesen „physiologisch normalen“ Bedingungen bestand zwischen der Taurinkonzentration in Plasma und Gesamtblut keine Korrelation (r=0.092). Die Plasmataurinkonzentration stieg nach oraler Taurinsupplementierung beim Menschen rasch an bzw. fiel schnell nach taurinfreier Ernährung bei Katzen ab. Die Taurinkonzentration im Gesamtblut war dagegen mehr inert und änderte sich erst nach anhaltender Taurinzufuhr beim Menschen bzw. nach andauerndem Taurinmangel bei Katzen.
    Notes: Summary In the present study the relationship between plasma and whole blood taurine was examined under normal physiological circumstances in humans and cats. In addition, the effect of taurine supplementation on plasma and whole blood taurine was evaluated in humans and the depletion of taurine pools after a taurine-deprived diet was studied in cats. The normal plasma taurine concentration in humans was 44±8 µmol/L and the whole blood taurine concentration was 227±35 µmol/L. Under normal physiological conditions plasma and whole blood taurine were not correlated (r=0.092). Plasma taurine responded rapidly to dietary supplementation in humans or the taurine depletion in cats. In contrast, the whole blood taurine pool was more inert and varied only under extremes of depletion (cats) or sustained taurine supplementation.
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  • 96
    ISSN: 1436-6215
    Keywords: Strontium ; oraler Strontium-Test ; Calcium ; Absorption ; gesunde Probanden ; Strontium ; oral strontium test ; calcium ; absorption ; healthy volunteers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
    Description / Table of Contents: Summary Intestinal strontium absorption has been discussed recently as an indirect measure for calcium uptake. Prerequisite for the clinical use of an oral strontium test is the availability of a reliable procedure including controlled strontium supply, sample pretreatment and analysis as well as the assessment of normal values. In the present study, a group of young females (n=33; 24.0 ± 2.7 y; BMI 21.5 ± 1.9) received an oral dose of 2.27 mmol strontium in a standardized breakfast that contained 0.625 mmol calcium. Before and 220 min after the bolus serum strontium concentrations were determined by means of atomic absorption spectrophotometry (coefficient of variation: within day 4.8 %, n=10; day-to-day 9.5 %, n=8). The error of the method was 2.7 %. Calculation of the fractional strontium absorption rate considered the respective distribution volume (extracellular fluid; either estimated using body weight or determined by means of bioimpedance analysis [BIA]). Average absorption rates were 13.3 ± 3.1 % and, considering BIA measurement 13.6 ± 2.6 %, respectively. Smoking, exercise and, use of oral contraceptives showed no effects. Our oral strontium test is characterized by excellent reliability, easy handling and low costs and, thus, is suitable for routine use.
    Notes: Zusammenfassung Die Erfassung der Strontiumabsorption wird heute als indirektes Verfahren zur Beurteilung der intestinalen Calciumabsorption diskutiert. Voraussetzung für die klinische Anwendung ist ein vertrauenswürdiges Testverfahren inclusive kontrollierter Strontiumgabe, Probenaufarbeitung und -analyse sowie die Erfassung von Normalwerten. Für unsere Studien wurde ein Kollektiv junger Frauen (n=33, 24,0 ± 2,7 Jahre; BMI 21,5 ± 1,9) herangezogen. Die Probandinnen erhielten eine Bolusgabe von 2,27 mmol Strontium zusammen mit einem Standardfrühstück (ca. 0,625 mmol Calcium). Vor und 220 min nach der Bolusgabe erfolgte die Bestimmung des Serum-Strontiumgehaltes mittels Atomabsorptionsspektrometrie. Der Variationskoeffizient der Methode lag innerhalb eines Tages bei 4,8 % (n=10) und von Tag zu Tag 9,5 % (n=8). Der Fehler der Methode betrug 2,7 %. Die Berechnung der fraktionellen Strontiumabsorptionsrate erfolgte unter Berücksichtigung des entsprechenden Verteilungsraumes (Extrazellulärflüssigkeit; Schätzverfahren über Körpergewicht bzw. Bioimpedanz-Analyse [BIA]). Die Strontiumabsorptionsrate lag im Mittel bei 13,3 ± 3,1 %, unter Berücksichtigung der BIA-Werte bei 13,6 ± 2,6 %. Rauchen, sportliche Aktivität bzw. Einnahme oraler Kontrazeptiva zeigten keinen Einfluß. Das hier vorgestellte Testverfahren ist aufgrund seiner hohen Vertrauenswürdigkeit und relativ einfacher Handhabung für Routine-untersuchungen geeignet.
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  • 97
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    European journal of nutrition 35 (1996), S. 1-1 
    ISSN: 1436-6215
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
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  • 98
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    European journal of nutrition 34 (1995), S. 214-219 
    ISSN: 1436-6215
    Keywords: Amylin ; food intake ; vagotomy ; circadian effect ; rat ; Amylin ; Futteraufnahme ; Vagotomie ; zirkadiane Effekte ; Ratte
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
    Description / Table of Contents: Zusammenfassung Das aus dem Pankreas stammende Peptid Amylin (1 µg/kg) reduzierte nach intraperitonealer (IP) Injektion die kumulative Futteraufnahme bei Ratten, denen vor der Injektion das Futter für 24 h entzogen worden war bzw. bei Ratten, denen Futter ad lib. zur Verfügung stand, für bis zu 4 h. Der Effekt trat zu verschiedenen Zeitpunkten des Tag/Nacht-Zyklus (Beginn der Dunkelphase, Mitte der Dunkelphase, Beginn der Hellphase) auf. Der verzehrsreduzierende Effekt von IP verabreichtem Amylin wurde zu keinem dieser Zeitpunkte durch subdiaphragmatische Vagotomie aufgehoben. Vagotomie führte eher zu einer Verstärkung des verzehrsreduzierenden Effekts von Amylin, und zwar nach einem 24stündigen Futterentzug bei Injektion zu Beginn der Hellphase oder in der Mitte der Dunkelphase. Im Unterschied zu früheren Untersuchungen mit älteren Ratten konnte ein verzehrsreduzierender Effekt von Amylin auch bei Ratten beobachtet werden, denen vor der Injektion das Futter nicht entzogen worden war. In Ergänzung früherer Befunde zeigen also die Ergebnisse, daß der verzehrsreduzierende Effekt von IP verabreichtem Amylin zu verschiedenen Tageszeiten ausgelöst und durch subdiaphragmatische Vagotomie nicht aufgehoben werden kann.
    Notes: Summary The pancreatic peptide amylin (1 µg/kg) injected intraperitoneally reduced cumulative food intake for up to 4 h in food-deprived (24 h) and non-deprived rats at various times of the day, i.e., at dark onset, in the middle of the dark phase, and at light onset. At none of these times did subdiaphragmatic vagotomy abolish the anorectic effect of amylin. Rather, vagotomy enhanced, by unknown mechanisms, amylin's anorectic effect in food-deprived rats at light onset and in the middle of the dark phase. In contrast to previous studies with older rats, amylin's anorectic effect was also observed when injected into nondeprived rats. The findings of the present study extend previous reports in that amylin's anorectic effect, not being abolished by abdominal vagotomy after intraperitoneal injection, can be elicited at different times of the day.
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  • 99
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    European journal of nutrition 34 (1995), S. 236-239 
    ISSN: 1436-6215
    Keywords: Verpflegungsplanung ; Krankenhausverpflegung ; Diabetesdiät ; Speisenauswahl ; wissensbasiertes System ; Menu planning ; hospital menu ; diabetes diet ; food selection ; knowledge-based system
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
    Description / Table of Contents: Summary Menu planning in hospitals is a complex decision problem. Patients expect the menu plan to be healthful and in accordance with their nutritional habits. Furthermore, the menu plan must conform to capacity limits of the kitchen. In this paper we present an approach to computerized food selection and menu composition. The model is based on nutritional knowledge, which is represented in the computer and used for problem solving.
    Notes: Zusammenfassung Die Planung einer Krankenhausverpflegung stellt sich als komplexes Entscheidungsproblem dar. Die Verpflegung soll der Gesundheit der Patienten zuträglich sein, deren Ernährungsgewohnheiten entsprechen und im Rahmen der Küchenkapazität hergestellt werden können. In der vorliegenden Arbeit wird am Beispiel der Diätverpflegung für Diabetiker ein computerunterstütztes Modell vorgestellt, das den Entscheidungsträgern im Krankenhaus Hilfestellung bei der Auswahl der Speisen und deren Zusammenstellung zu Menüs bietet. Die Planung erfolgt auf der Basis ernährungs- und haushaltswissenschaftlichen Fachwissens, das im Computer abgebildet und zur Problemlösung genutzt wird.
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  • 100
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    European journal of nutrition 35 (1996), S. 39-44 
    ISSN: 1436-6215
    Keywords: Dietary fibers ; agro industrial wastes ; serum lipids ; liver lipids ; Diäterische Fasern ; industrielle Agrarabfälle ; Serumlipide ; Leberlipide
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
    Description / Table of Contents: Zusammenfassung Albino-Ratten wurden für 8 Wochen 3 Diäten unterworfen. Diät I bestand aus nicht-faseriger hoch-halliger Kohlenhydratkostform. Diät II und Diät III enthielten zusäzlich 100 g/kg mitEndomycopsis fibuligera kultivierte faserige Dattelabfälle. Die Kultivierungszeit betrug 0 (II) und 60 Stunden (III). Die Gesamtlipide, das Gesamtcholesterol, die Triglyzeride und die Phospholipide nahmen in den Lebern der Ratten, die mit Diät II und III gefüttert wurden, deutlicher ab, als bei denjenigen, die mit Diät I gefüttert wurden. Bei der Diät III zeigte sich die höchste Abnahme der verschiedenen Untersuchungsparametern. Vergleicht man Diät II und III mit Diät I, so ergibt sich, daß die Serumgesamtlipide und das Lipoprotein-Cholesterol niedrigerer Dichte (LDL-Cholesterol) um 32–48 % abnehmen, während Serumtriglyzeride und Gesamtcholesterol in mit Dät II und Diät III gefütterten Ratten um 23–35 % erniedrigt sind. Bei mit Diät II und III gefütterten Ratten betrug die Abnahme des HDL-Cholesterols nur 2–6 %. Phospholipide zeigten die höchste Abnahme (51–56 %) während der ganzen Versuchsperiode (8 Wochen).
    Notes: Summary Date waste dietary fibers were examined as a hypolipidemic agent. White albino rats were fed on three experimental diets: I) high carbohydrate diet free of fiber; II) and III) diets consisted of diet I substituted with 100 g/kg of date waste dietary fibers cultured withEndomycopsis fibuligera at zero time and after 60 h of culturing respectively for 8 weeks. The total lipids, total cholesterol, triglycerides and phospholipids in the liver of rats given diets II and III were significantly decreased over those rats fed the control diet throughout the feeding period (8 weeks). The highest decrease in content of all these parameters was produced by diet III. Comparing diets II and III with the control diet I, total serum lipids and low density lipoprotein cholesterol (LDL-cholesterol) were decreased by 32–48 %, while serum triglycerides and total cholesterol levels were lowered in the groups fed diets II and III by 23–35 % respectively. Concerning high density lipoprotein cholesterol (HDL-cholesterol), the decrease was only 2–6 % in rats fed diets II and III. The highest decrease level was shown in the phospholipids content (51–56 %) during all of the experimental period (8 weeks).
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