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  • 1
    Digitale Medien
    Digitale Medien
    Springer
    Stochastic environmental research and risk assessment 1 (1987), S. 1-2 
    ISSN: 1436-3259
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Architektur, Bauingenieurwesen, Vermessung , Energietechnik , Geographie , Geologie und Paläontologie
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    Springer
    Stochastic environmental research and risk assessment 1 (1987), S. 3-16 
    ISSN: 1436-3259
    Schlagwort(e): Annual maximum ; partial duration series ; T-year estimate ; marshall-Olkin bivariate distribution ; Morgenstern bivariate distribution
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Architektur, Bauingenieurwesen, Vermessung , Energietechnik , Geographie , Geologie und Paläontologie
    Notizen: Abstract As a basis for development of the annual maximum distribution the so-called partial duration series with Poissonian occurrence times and exponentially distributed peak exceedance values has been selected. The model is generalized by allowing for a Markov dependence between succeeding peak values. Correlation values from p=0 to p=1 can be accounted for by introducing the Marshall-Olkin bivariate exponential distribution, which is presented in detail. The developed distribution function for the annual maximum is throughly analysed and a variety of distribution forms depending on the value of the correlation coefficient and the intensity in the Poisson process is hereby recognized. To a certain extent this might be considered as parallel to the scattering of hydrological regions with different generating mechanisms for the annual maxima.
    Materialart: Digitale Medien
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  • 3
    Digitale Medien
    Digitale Medien
    Springer
    Stochastic environmental research and risk assessment 1 (1987), S. 37-52 
    ISSN: 1436-3259
    Schlagwort(e): Cyclonic precipitation ; mathematical modeling ; simulation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Architektur, Bauingenieurwesen, Vermessung , Energietechnik , Geographie , Geologie und Paläontologie
    Notizen: Abstract A stochastic description is developed for extratropical cyclonic precipitation fields at synoptic and meso scales as they are typically observed by radars over the Earth. This description attempts to account I) for the synoptic scale behavior of a cyclonic storm (its birth, its synoptic scale motion trajectory, and its dissipation) II) for the synoptic-scale organizational structure of subsynoptic precipitation areas (rainbands, precipitation cores and raincells) within a cyclonic storm; and III) for the behavior of subsynoptic precipitation areas, in terms of their births, their spatial configuration evolutions, their motions, and their deaths (dissipation). The precipitation cores and the raincells are taken as the building blocks of the subsynoptic precipitation, areas within a cyclonic rainfield.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 4
    Digitale Medien
    Digitale Medien
    Springer
    Stochastic environmental research and risk assessment 1 (1987), S. 81-100 
    ISSN: 1436-3259
    Schlagwort(e): Stochastic differential equations ; Itô calculus ; Stratovovich integrals ; Jump integrals
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Architektur, Bauingenieurwesen, Vermessung , Energietechnik , Geographie , Geologie und Paläontologie
    Notizen: Abstract Fundamentals of the theory of stochastic calculus and stochastic differential equations (SDE's) which are finding increasing application in water resources engineering are reviewed. The basics of probability theory, mean square calculus and the Wiener, white Gaussian and compound Poisson processes are given in preparation for a discussion of the general Itô SDE with drift, diffusion and jump discontinuity terms driven by Gaussian white noise and compound Poissionian impulses. Also discussed are stochastic integration and the derivation of moment equations via the Itô differential rule. The lierature of SDE's is reviewed with an emphasis on the more accessible sources.
    Materialart: Digitale Medien
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  • 5
    Digitale Medien
    Digitale Medien
    Springer
    Stochastic environmental research and risk assessment 1 (1987), S. 53-66 
    ISSN: 1436-3259
    Schlagwort(e): Hurst range ; conditioned exchangeable, variables
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Architektur, Bauingenieurwesen, Vermessung , Energietechnik , Geographie , Geologie und Paläontologie
    Notizen: Abstract A new theoretical interpretation is proposed for Hurst's empirical law which is applicable to discrete-valued inflows and is consistent with the existing interpretation for continuous-valued inflows. This is applied to independent net inflows {X r} having values +1 and −1 with unequal probabilities. With the aid of a new result on the exchangeability of symmetrically conditioned exchangeable variables, values of the resulting range are obtained and tabulated. It is found that the effect of skewness is very slight for skewness values between (about) 3 and −3, and that Hurst's own approximation, the “conditioned range”, is remarkably accurate.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 6
    Digitale Medien
    Digitale Medien
    Springer
    Stochastic environmental research and risk assessment 1 (1987), S. 67-80 
    ISSN: 1436-3259
    Schlagwort(e): pattern analysis ; mixed-mode data ; event-covering ; discretization ; hydrometric data
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Architektur, Bauingenieurwesen, Vermessung , Energietechnik , Geographie , Geologie und Paläontologie
    Notizen: Abstract This paper presents a pattern analysis technique that has been successfully applied to a set of hydrometric network data collected in British Columbia, Canada. This technique can extract information from a set of observed heterogeneous multivariate data. The data are represented as n-tuples of mixed discrete and continuous values. The technique is capable of screening out statistically irrelevant information. It is also able to detect inherent subgroups in the data through adopting an event-covering approach. The subgroup characteristics represent important empirical understanding even though there may be considerable probabilistic variation within each individual subgroup.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 7
    Digitale Medien
    Digitale Medien
    Springer
    Stochastic environmental research and risk assessment 1 (1987), S. 17-36 
    ISSN: 1436-3259
    Schlagwort(e): Stochastic hydrology ; multivariate analysis ; information extraction ; information transfer ; structure of time series ; time series analysis ; spatial characteristics ; simulation of processes
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Architektur, Bauingenieurwesen, Vermessung , Energietechnik , Geographie , Geologie und Paläontologie
    Notizen: Abstract A stochastic approach to the analysis of hydrologic processes is defined along with a discussion of causes of tendency, periodicity and stochasticity in hydrologic series. Sources of temporal non-stationarity are described along with objectives and methods of analysis of processes and, in general, of information extraction from data. Transferred information as measured by correlation coefficients is compared with the transferable information as measured by entropy coefficients. Various multivariate approaches to hydrologic stochastic modeling are classified in light of complexities of spatial/temporal hydrologic processes. Alternatives of time series structural decomposition and modeling are compared. A special approach to modeling of space properties further contributes to approximate simulations of spatial/temporal processes over large areas. Several aspects of stochastic models in hydrology are concisely reviewed.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 8
    Digitale Medien
    Digitale Medien
    Springer
    Stochastic environmental research and risk assessment 1 (1987), S. 101-116 
    ISSN: 1436-3259
    Schlagwort(e): Soil moisture ; stochastic processes ; stochastic differential equations
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Architektur, Bauingenieurwesen, Vermessung , Energietechnik , Geographie , Geologie und Paläontologie
    Notizen: Abstract The dynamics of water within the unsaturated root zone of the soil are represented by a pair of stochastic differential equations (SDE's), one representing the so-called “surplus” state of the moisture and the other the “deficit” condition. The inputs to the model are the climatically controlled random infiltration events and evapotranspiration which are modeled as a compound Poisson process and a Wiener (Brownian motion) process, respectively. The solutions to these SDE's are not in “close-form” but sample functions are obtained by numerical integration. The moment properties of the soil moisture evolution process have also been derived analytically including the mean, variance, covariance and autocorrelation functions. To illustrate the model, climatic parameters representing the “surplus” and “deficit” cases and properties of clay loam soil have been used to numerically derived the corresponding sample functions. With proper selection of all the parameters, physically realistic sample trajectories can be obtained for the model.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 9
    Digitale Medien
    Digitale Medien
    Springer
    Stochastic environmental research and risk assessment 1 (1987), S. 127-134 
    ISSN: 1436-3259
    Schlagwort(e): Upland erosion ; annual erosion losses
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Architektur, Bauingenieurwesen, Vermessung , Energietechnik , Geographie , Geologie und Paläontologie
    Notizen: Abstract Point rainfall triggers the complex processes of overland flow and surface erosion. The probability density functions of rainfall duration and intensity are coupled with a physically based dynamic formulation of rainfall-runoff-sediment transport relationships for upland areas. When considering a single storm, rainfall depth alone is a poor predictor of sediment transport because of the dispersion introduced by the effect of rainfall intensity. On a long terms basis, however, the total amount of rainfall can be used to predict total erosion losses.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 10
    Digitale Medien
    Digitale Medien
    Springer
    Stochastic environmental research and risk assessment 1 (1987), S. 117-126 
    ISSN: 1436-3259
    Schlagwort(e): equi-risk line ; detention pond ; urban runoff ; frequency analysis ; flood risk
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Architektur, Bauingenieurwesen, Vermessung , Energietechnik , Geographie , Geologie und Paläontologie
    Notizen: Abstract The expression of equi-risk line derived by the authors represents the relationship between discharge capacityy 0 u and storage capacityz 0 u to keep flood frequency under a certain risk level represented by the return periodT, i.e.,z 0/z 0 u ={(y 0 u −y 0 u )/y 0 u } S , wherey 0 u andz 0 u areT-year probability peak discharge and total volume of a hydrograph. The shape parametersS is evaluated in this paper for various release rules of the storage facilities and correlations of durations and peaks of hydrographs. The expression forS is: $$S = S_\infty + (S_0 - S_\infty )\exp ( - \sqrt p )$$ , whereS 0 andS ∞ are the values ofS forp=0 and ∞, andp is the exponent of a general storage-release relation,q=az' p, wherea is the storage constant, andz' andq are the volume of stored water and the corresponding release. The values ofS 0 andS ∞ are expressed in terms of the correlation coefficient ρ of durations and peaks of inflow hydrographs.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 11
    Digitale Medien
    Digitale Medien
    Springer
    Stochastic environmental research and risk assessment 1 (1987), S. 135-140 
    ISSN: 1436-3259
    Schlagwort(e): Upland erosion ; annual soil losses
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Architektur, Bauingenieurwesen, Vermessung , Energietechnik , Geographie , Geologie und Paläontologie
    Notizen: Abstract Annual erosion losses from 135 experimental plots under a variety of soil types, vegetation cover densities and conservation practices in Iraq have been measured over a period of four years. The first three years of this data set demonstrate that annual erosion losses can be predicted from annual rainfall depths. The results obtained from regression analysis were then validated with the fourth year of soil erosion data. These results corroborate the theoretical findings of the companion paper in that long term erosion losses can be predicted from the total amount of rainfall.
    Materialart: Digitale Medien
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  • 12
    Digitale Medien
    Digitale Medien
    Springer
    Stochastic environmental research and risk assessment 1 (1987), S. 141-154 
    ISSN: 1436-3259
    Schlagwort(e): Contemporaneous ARMA models ; maximum likelihood estimation ; multivariate modelling ; stochastic hydrology ; time series analysis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Architektur, Bauingenieurwesen, Vermessung , Energietechnik , Geographie , Geologie und Paläontologie
    Notizen: Abstract In order to allow contemporaneous autoregressive moving average (CARMA) models to be properly applied to hydrological time series, important statistical properties of the CARMA family of models are developed. For calibrating the model parameters, efficient joint estimation procedures are investigated and compared to a set of uivariate estimation procedures. It is shown that joint estimation procedures improve the efficiency of the autoregressive and moving average parameter estimates, but no improvements are expected on the estimation of the mean vector and the variance covariance matrix of the model. The effects of the different estimation procedures on the asymptotic prediction error are also considered. Finally, hydrological applications demonstrate the usefulness of the CARMA models in the field of water resources.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 13
    Digitale Medien
    Digitale Medien
    Springer
    Stochastic environmental research and risk assessment 1 (1987), S. 155-160 
    ISSN: 1436-3259
    Schlagwort(e): Gamma Markov ; estimation ; maximum likelihood estimates
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Architektur, Bauingenieurwesen, Vermessung , Energietechnik , Geographie , Geologie und Paläontologie
    Notizen: Abstract The linearly regressive Gamma Markov sequence is being increasingly used as a model for geophysical phenomena, one of the reasons being that it is possible to determine the distribution of (weighted or otherwise) cumulative sums of such a sequence. In this paper we show briefly how to simulate such a sequence and its seasonal extension; we also show how to estimate its parameters. It is shown that the estimates obtained by the method of moments do not have a high efficiency, whereas those obtained by a modified maximum likelihood method have an efficiency close to unity.
    Materialart: Digitale Medien
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  • 14
    Digitale Medien
    Digitale Medien
    Springer
    Stochastic environmental research and risk assessment 1 (1987), S. 161-168 
    ISSN: 1436-3259
    Schlagwort(e): Inverse problem ; groundwater management ; groundwater response function ; stochastic control ; consistent parameter estimation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Architektur, Bauingenieurwesen, Vermessung , Energietechnik , Geographie , Geologie und Paläontologie
    Notizen: Abstract The response of groundwater basins to natural and anthropogenic inputs depends on many interrelated factors such as the values of groundwater flow and mass transport parameters. This work presents a theoretical analysis of the impact of parameter uncertainty on groundwater management decisions. It is shown that under classical, Bayesian, and deterministic assumptions about the parameter structure, the resulting management decisions could be very different. This underscores the importance of adopting the proper parameter structure and the need for using consistent methods to solve the inverse problem.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 15
    Digitale Medien
    Digitale Medien
    Springer
    Stochastic environmental research and risk assessment 1 (1987), S. 185-198 
    ISSN: 1436-3259
    Schlagwort(e): Pattern matching ; tracking ; rainfall ; mesoscale ; radar
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Architektur, Bauingenieurwesen, Vermessung , Energietechnik , Geographie , Geologie und Paläontologie
    Notizen: Abstract This paper presents a new feature-based matching algorithm for tracking mesoscale precipitation phenomena in radar image sequences. Distinct rainfall areas are identified in each image and characterized by a feature vector of shape descriptors, which provide a mathematical representation of the spatial characteristics of each identified area. Rainfall areas observed in consecutive images are matched by comparing the relative values of the features. Two match scoring algorithms are developed to generate the initial estimates of correct matches, which are then updated by likelihood measures based on relative location. The method is applied to mesoscale rainfall areas observed in sequences of radar-derived images of rainfall activity over Southwestern Ontario during the summers of 1980 and 1981.
    Materialart: Digitale Medien
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  • 16
    Digitale Medien
    Digitale Medien
    Springer
    Stochastic environmental research and risk assessment 1 (1987), S. 199-208 
    ISSN: 1436-3259
    Schlagwort(e): Extreme value distribution ; two-component distribution ; maximum entropy principle ; parameter estimation ; regional estimation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Architektur, Bauingenieurwesen, Vermessung , Energietechnik , Geographie , Geologie und Paläontologie
    Notizen: Abstract The two component extreme value (TCEV) distribution has recently been shown to account for most of the characteristics of the real flood experience. A new method of parameter estimation for this distribution is derived using the principle of maximum entropy (POME). This method of parameter estimation is suitable for application in both the site-specific and regional cases and appears simpler than the maximum likelihood estimation method. Statistical properties of the regionalized estimation were evaluated using a Monte Carlo approach and compared with those of the maximum likelihood regional estimators.
    Materialart: Digitale Medien
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  • 17
    Digitale Medien
    Digitale Medien
    Springer
    Stochastic environmental research and risk assessment 1 (1987), S. 169-184 
    ISSN: 1436-3259
    Schlagwort(e): Stochastic control and programming ; real-time hydrologic forecasting ; reservoir theory
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Architektur, Bauingenieurwesen, Vermessung , Energietechnik , Geographie , Geologie und Paläontologie
    Notizen: Abstract A new approximate method of solution for stochastic optimal control problems with many state and control variables is introduced. The method is based on the expansion of the optimal control into the deterministic feedback control plus a caution term. The analytic, small-perturbation calculation of the caution term is at the heart of the new method. The developed approximation depends only on the first two statistical moments of the random inputs and up to the third derivatives of the cost functions. Its computational requirements do not exhibit the exponential growth exhibited by discrete stochastic DP and can be used as a suboptimal solution to problems for which application of stochastic DP is not feasible. The method is accurate when the cost-to-go functions are approximately cubic in a neighbourhood around the deterministic trajectory whose size depends on forecasting uncertainty. Furthermore, the method elucidates the stochastic optimization problem yielding insights which cannot be easily obtained from the numerical application of discrete DP.
    Materialart: Digitale Medien
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  • 18
    Digitale Medien
    Digitale Medien
    Springer
    Stochastic environmental research and risk assessment 1 (1987), S. 209-216 
    ISSN: 1436-3259
    Schlagwort(e): Transport ; sedimentation ; random walk ; Markov chain in continuous time ; distribution of maximum
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Architektur, Bauingenieurwesen, Vermessung , Energietechnik , Geographie , Geologie und Paläontologie
    Notizen: Abstract A simple two-dimensional random walk model is developed for the motion of a particle in a fluid flow. Some earlier results for the persistent injection of particles into the flow are extended, and the distribution of the maximum number of particles in suspension over the period (0,t) is derived.
    Materialart: Digitale Medien
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  • 19
    Digitale Medien
    Digitale Medien
    Springer
    Stochastic environmental research and risk assessment 1 (1987), S. 217-240 
    ISSN: 1436-3259
    Schlagwort(e): Transport of fluid ; random network ; macro-permeability ; micro-geometry ; statistical mechanics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Architektur, Bauingenieurwesen, Vermessung , Energietechnik , Geographie , Geologie und Paläontologie
    Notizen: Abstract This paper presents a detailed statistical analysis of Hagen-Poiseuille flow in plane random isotropic networks of interconnected channels. The emphasis is on statistico-geometrical features of networks that affect macroscopic permeability. It is shown that permeability of a network depends on its average co-ordination number, the first two moments of the channel length distribution and other explicitly identifiable geometrical features. Distributions of flow rates in channels and average flow rates are established by minimization of the rate of energy dissipation. Theoretical developments are interpreted in the context of classical statistical mechanics. Analytical results are illustrated and verified using numerical analysis of flow in a simulated random network.
    Materialart: Digitale Medien
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  • 20
    Digitale Medien
    Digitale Medien
    Springer
    Stochastic environmental research and risk assessment 1 (1987), S. 280-280 
    ISSN: 1436-3259
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Architektur, Bauingenieurwesen, Vermessung , Energietechnik , Geographie , Geologie und Paläontologie
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 21
    Digitale Medien
    Digitale Medien
    Springer
    Stochastic environmental research and risk assessment 1 (1987), S. 241-262 
    ISSN: 1436-3259
    Schlagwort(e): Martingale ; stochastic-convective ; stochastic-relativist ; spectral-integral ; perturbative ; statistical-mechanical
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Architektur, Bauingenieurwesen, Vermessung , Energietechnik , Geographie , Geologie und Paläontologie
    Notizen: Abstract The use of stochastic models in subsurface hydrology is growing at a logistic pace. To tie together a number of different stochastic methodologies for deriving subsurface transport equations, we have put together a brief review of some of the more common techniques. Our attention is confined to a few select methodologies so that we might delve in detail into assumptions required by the various approaches and their strengths and weaknesses. The methods reviewed include: Martingale, stochastic-convective, stochastic-relativist, spectral-integral, perturbative, statistical-mechanical, and generalized hydrodynamics. Within this list, we also have included a few stochastic methodologies which have been used solely to develop expressions for the dispersion tensor.
    Materialart: Digitale Medien
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  • 22
    Digitale Medien
    Digitale Medien
    Springer
    Stochastic environmental research and risk assessment 1 (1987), S. 297-302 
    ISSN: 1436-3259
    Schlagwort(e): Stochastic PDE ; Zakai equation ; nonlinear filtering ; distributed systems
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Architektur, Bauingenieurwesen, Vermessung , Energietechnik , Geographie , Geologie und Paläontologie
    Notizen: Abstract We shall consider in this article a general class of stochastic PDE which in particular covers the Zakai equation of nonlinear filtering and natural formulations of distributed systems involving control variables. We use only fixed point arguments, hence we get uniqueness results. In the case of the Zakai equation, Galerkin approximations have been considered by Pardoux (1979) to derive the existence of the solution
    Materialart: Digitale Medien
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  • 23
    Digitale Medien
    Digitale Medien
    Springer
    Stochastic environmental research and risk assessment 1 (1987), S. 281-296 
    ISSN: 1436-3259
    Schlagwort(e): Stochastic groundwater flow ; semigroups ; random in time Gaussian process ; random physical parameters ; stochastic partial differential equations
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Architektur, Bauingenieurwesen, Vermessung , Energietechnik , Geographie , Geologie und Paläontologie
    Notizen: Abstract Two methods for the solution of partial differential equations (PDE) for the general case of random in time physical parameters are presented and their application to the solution of unsteady regional groundwater flow equations are illustrated. The first method is the semigroup approach which directly offers a solution without resorting to “closure approximations” (hierarchy techniques), perturbation techniques, or Montecarlo simulation techniques. The semigroup approach can also handle the general stochastic problem when randomness also appears as initial conditions, boundary conditions or forcing terms. The second method is an approximation scheme to obtain the semigroup solution in complex cases and permits the solution of equations with more than one random coefficient.
    Materialart: Digitale Medien
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  • 24
    Digitale Medien
    Digitale Medien
    Springer
    Stochastic environmental research and risk assessment 1 (1987), S. 303-318 
    ISSN: 1436-3259
    Schlagwort(e): Rainfall-runoff models ; forecasting ; unit hydrograph
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Architektur, Bauingenieurwesen, Vermessung , Energietechnik , Geographie , Geologie und Paläontologie
    Notizen: Abstract Here we review the main thrusts of rainfall-runoff modelling with an eye toward the advantageous use of the massive date sets being accumulated and the modern computers capable of dealing effectively with such sets. More than a tutorial, this study is aimed at providing a unifying structure for analyzing available techniques. The closing section draws attention to the existence of an alternative methodology.
    Materialart: Digitale Medien
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  • 25
    Digitale Medien
    Digitale Medien
    Springer
    Stochastic environmental research and risk assessment 1 (1987), S. 263-279 
    ISSN: 1436-3259
    Schlagwort(e): Porous media ; heterogeneity ; groundwater ; dispersion ; stochastic theory ; plume evolution
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Architektur, Bauingenieurwesen, Vermessung , Energietechnik , Geographie , Geologie und Paläontologie
    Notizen: Abstract The migration of contaminants in heterogeneous aquifers involves dispersive processes that act at different scales. The interaction of these processes as a plume evolves can be studied by micro-scale modelling whereby two scales, a local- or micro-scale and an aquifer- or macro-scale, are covered simultaneously. Local-scale dispersive processes are represented through the local dispersion coefficient in the transport equation, while large-scale dispersion due to heterogeneities is represented through the resolution of the flow field and the diffusive exchange between streamtubes. The micro-scale model provides both the high degree of resolution compatible with local-scale processes, and the extent required for the approach to asymptotic conditions, using grids of up to a million nodal points. The model is based on the dual potential-streamfunction formulation for flow, and the transport problem is formulated in a natural coordinate system provided by the flownet. Simulations can be used to verify stochastic theories of dispersion, without the restrictive assumptions inherent in the theory. For the two-dimensional case, results indicate convergence of the effective dispersivity to the theoretical macrodispersivity value. Convergence takes place within a travel distance of about 50 correlation lengths of the hydraulic conductivity field. However, the approach taken to asymptotic conditions, as well as the macrodispersivity value, may differ for different realizations of the same medium. The influence of early-time events such as plume splitting on the asymptotic convergence remains to be investigated.
    Materialart: Digitale Medien
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  • 26
    Digitale Medien
    Digitale Medien
    Springer
    European journal of nutrition 26 (1987), S. 1-6 
    ISSN: 1436-6215
    Schlagwort(e): Zn-deficiency ; vitamin A ; Β-carotine ; α-tocopherol
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft , Medizin
    Beschreibung / Inhaltsverzeichnis: Summary In order to study the effect of alimentary zinc deficiency on vitamin A and α-tocopherol metabolism, weaned, male Sprague-Dawley rats with a mean weight of 48 g were divided into three groups. Zinc depletion animals (n=7) were provided a half-synthetic, casein-based diet with a zinc concentration of 1.3 ppm; the pair-fed (n=7) and ad libitum-fed (n=6) control animals were given a diet containing 96 ppm zinc. After 24 days, the serum zinc level for depletion animals was 80 % lower than the level for the two control groups, although the vitamin A, Β-carotine and tocopherol concentrations in deficiency animals and in pair-fed control animals did not differ significantly from one another. In comparison with adlibitum-fed control rats, however, vitamin A and Β-carotine concentrations in depletion and pair-fed animals were elevated. The zinc concentration in livers of deficiency animals was reduced only in comparison to the value for pair-fed control animals, while the vitamin A, Β-carotine and α-tocopherol concentrations in livers of zinc-deficient animals were reduced in comparison to the values for both of the control groups. Nevertheless, these changes are less likely a result of zinc deficiency per se, but rather are more likely a result of the lowered feed intake during zinc deficiency and the reduced growth.
    Notizen: Zusammenfassung Um den Einfluß eines alimentären Zinkmangels auf den Vitamin-A- und α-Tocopherol-Stoffwechsel zu untersuchen, wurden entwöhnte männliche Sprague-Dawley-Ratten mit einem Durchschnittsgewicht von 48 g in drei Gruppen eingeteilt. Die Zn-Mangel-Tiere (n=7) erhielten eine halbsynthetische Diät auf Caseinbasis mit einem Zn-Gehalt von 1,3 ppm, während der Diät-Zn-Gehalt der Pair-fed-Kontrolltiere (n=7) bzw. der ad libitum gefütterten Kontrolltiere (n=6) 96 ppm betrug. Nach 24 Versuchstagen lag der Serum-Zn-Spiegel der Depletionstiere um 80% unter den beiden Kontrollgruppen, während sich die Gehalte an Vitamin A, Β-Carotin und Tocopherol bei den Mangeltieren im Vergleich zu den Pair-fed-Kontrolltieren nicht signifikant unterschied. Gegenüber den ad libitum gefütterten Kontrollratten waren aber die Gehalte an Vitamin A und Β-Carotin bei den Depletions- und Pair-fed-Ratten erhöht. In der Leber war die Zn-Konzentration der Mangeltiere nur gegenüber den Pair-fed-Kontrolltieren reduziert, während die Gehalte an Vitamin A, Β-Carotin und α-Tocopherol bei den Zn-Mangel-Ratten gegenüber beiden Kontrollgruppen erniedrigt waren. Diese Veränderungen dürften jedoch weniger durch Zn-Mangel — per se — bedingt sein, sondern sind vielmehr im Zusammenhang mit der im Zn-Mangel verringerten Futteraufnahme und dem reduzierten Wachstum zu diskutieren.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 27
    Digitale Medien
    Digitale Medien
    Springer
    European journal of nutrition 26 (1987), S. 73-78 
    ISSN: 1436-6215
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft , Medizin
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 28
    Digitale Medien
    Digitale Medien
    Springer
    European journal of nutrition 26 (1987), S. 100-106 
    ISSN: 1436-6215
    Schlagwort(e): cottonseedflour ; wheatflour ; bread making
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft , Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Baumwollsaatmehl (eßbare Qualität) wurde in Anteilen von 5, 10 und 15% einem saudiarabischen Weizenmehl zur Brotbereitung zugemischt. Dies führte zu einem Anstieg der Wasserbindung des Teiges. Die Zeiten zur Teigbereitung, die Teigstabilität und das Abreißverhalten wurden mit niedrigen Zusatzmengen geringfügig erhöht; die höheren Zusatzmengen hatten umgekehrte Wirkung. Ein Zusatz von 5–10% Baumwollsaatmehl konnte bezüglich Teigeigenschaften und Brotqualität toleriert werden; die Qualität des zugesetzten Produktes war allerdings maßgebend. Auf diese Weise konnte eine Erhöhung des Proteingehaltes der Brote um 25–50% erreicht werden.
    Notizen: Summary Three samples of edible grade cottonseed flour (cosf) were utilized each in 5%, 10% and 15% mixtures with Saudi wheat flour for bread making. Addition of cosf increased water absorption of the dough. Times of dough mixing, stability and break-down were slightly increased at the low addition level, but adversely shortened at the higher levels, where mixing tolerance was doubled or tripled. Up to 5%–10% of cosf could be tolerated without deleterious effect on dough properties or bread quality, depending on the source of the additive and method of preparation. An increase of 25%–50% in protein content of bread was expected.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 29
    Digitale Medien
    Digitale Medien
    Springer
    European journal of nutrition 26 (1987), S. 219-225 
    ISSN: 1436-6215
    Schlagwort(e): dietarycottonseed protein ; serumcholesterol ; gallstones
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft , Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Eiweiß aus Baumwollsamen, das wenig Gossypol enthält, könnte für die Humanernährung ein wichtiges Produkt werden. In diesem Artikel wird der Einfluß von Eiweiß aus Baumwollsamen auf den Cholesterinstoffwechsel beschrieben. Versuche mit Kaninchen und Ratten zeigten, daß Baumwollsameneiweiß die Serumcholesterinkonzentration im Vergleich zum tierischen Eiweiß, Kasein, sehr stark erniedrigt. Dieser Effekt wurde bei Hamstern nicht beobachtet, aber Baumwollsameneiweiß erhöhte den Anteil des Gesamtserumcholesterins in der HDL-Lipoproteingruppe ein wenig. Es gibt Hinweise dafür, daß bei Menschen der Ersatz von tierischem Eiweiß durch Baumwollsameneiweiß in der Nahrung eine geringe Abnahme des Serumcholesterinspiegels verursacht, jedoch sind noch Studien erforderlich, um dies zu untermauern. Bei Hamstern unterdrückt Baumwollsameneiweiß, im Vergleich mit Kasein, die Bildung von Gallensteinen. Bei Diäten, die Baumwollsameneiweiß enthalten, sind sowohl die Konzentration von Cholesterin sowie auch von Phospholipiden in der Gallenflüssigkeit signifikant erniedrigt. Wir vermuten, daß der Konsum von Baumwollsameneiweiß einen günstigen Effekt auf den Cholesterinmetabolismus hat.
    Notizen: Summary Low-gossypol, glandless cottonseed protein may become a major product for human consumption. In this presentation, the influence of cottonseed protein on several aspects of cholesterol metabolism will be described. Studies with rabbits and rats have shown that dietary cottonseed protein very effectively lowers the concentration of plasma cholesterol when compared to the animal protein casein. No such effect has been found in hamsters, but cottonseed protein may slightly elevate the percentage of serum total cholesterol carried by the high density lipoproteins. There is suggestive evidence that in humans the replacement of animal proteins in the diet by cottonseed protein causes a small decrease in serum cholesterol levels, but more studies are required to substantiate this. In hamsters dietary cottonseed protein effectively suppresses the formation of gallstones when compared to casein. On diets containing cottonseed protein the concentrations of both cholesterol and phospholipids in bile fluid are significantly decreased. We tentatively suggest that the consumption of cottonseed protein will have a favorable effect on cholesterol metabolism.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 30
    Digitale Medien
    Digitale Medien
    Springer
    European journal of nutrition 26 (1987), S. 230-249 
    ISSN: 1436-6215
    Schlagwort(e): ovo-laktovegetarische Kost ; Verzehr an Lebensmitteln ; Nährstoffversorgung ; Blutstatus
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft , Medizin
    Beschreibung / Inhaltsverzeichnis: Summary The purpose of the study was to investigate the physiological assessment of a lacto-ovo-vegetarian diet, in comparison to a usual mixed diet and to analyse the effect of a lacto-ovo-vegetarian diet on nutritional status and blood parameters. Following an initial study, 34 resp. 33 subjects, three of them male took part in two investigation periods each lasting three weeks. During the first period (N) the subjects ingested the normal mixed diet, while in the second period (L) they were fed a lacto-ovo-vegetarian diet. The female subjects were aged 52.6±14.3 years, the male subjects 47.7±12.7 years. In both periods food supply ensued from the central kitchen of a nunnery. While preparing the meals, the food intake and the amount of nutrients was assessed with precise weighing methods. Also, the individual food consumption of the total subjects was estimated using food records. The nutritional physiological evaluation was based on the daily consumption of energy and nutrients to assess the nutrient supply, by means of the recommended dietary allowances of the German Nutrition Society. At the beginning of period N and both at the beginning and the end of period L, blood tests of the following parameters were performed: serum glucose, uric acid, and potassium, total protein, total cholesterol, HDL-, LDL-, VLDL-cholesterol, triglycerides, serum ferritin, serum iron, iron binding capacity, hemoglobin, s-GOT, s-GPT, thiamine, riboflavine, ascorbic acid. Measurements of body weight and height, body composition, skinfold thickness, circumferences, body surface, relative weight, blood pressure and sitting pulse rate completed the investigations. Furthermore, meal frequency and the daily individual energy requirement of the subjects were assessed by means of a diary of energy expenditure. On average, the daily energy consumption of women was 2020±611.3 kcal in period N, and 1970±592.4 kcal in period L. Consequently, there was a covering of energy requirements of 103% in period N and 99% in period L. Sources of energy consisted of 14% protein, 36,4% fat and 49,6% carbohydrates in period L, 13.6 % protein, 39.6% fat, 44.7% carbohydrates and 2.1% alcohol in period N.
    Notizen: Zusammenfassung Ziel der Untersuchung war der Vergleich einer ovo-laktovegetarischen Ernährung mit üblicher Mischkost (Heimverpflegung) auf Ernährungs- und Blutstatus. Nach einer Pilotstudie erfolgten zwei dreiwöchige Versuchsperioden mit 34 bzw. 33 Probanden, davon jeweils drei Männern. Während der 1. Erhebungsperiode (N) erhielten die Probanden ihre gewohnte Mischkost, während der 2. Erhebungsperiode (L) eine ovo-laktovegetarische Kostform. Die weiblichen Vpn waren im Durchschnitt 52,6±14,3 Jahre alt, die männlichen 47,7±12,7 Jahre. Die Verpflegung der Probanden in beiden Erhebungsperioden erfolgte aus der Zentralküche eines Klosters. Das Lebensmittelangebot wurde bei der Speisenzubereitung nach der präzisen Wiegemethode erfaßt. Außerdem erfolgte eine Erhebung des individuellen Lebensmittelverzehrs aller Probanden nach der Protokollmethode. Die ernährungsphysiologische Auswertung basiert auf der täglichen Energie- und Nährstoffzufuhr der Probanden, um diese mit der empfehlenswerten Höhe der Nährstoffzufuhr zu überprüfen. Zu Beginn von Periode N sowie zu Beginn und am Ende von Periode L erfolgten Blutuntersuchungen in bezug auf: Serumglukose, -harnsäure, -kalium, Gesamteiweiß, Gesamtcholesterin, HDL-, LDL-, VLDL-Cholesterin, Triglyzeride, Serumferritin, Serumeisen, Eisenbindungskapazität, Hämoglobin, s-GOT, S-GPT, Vit. B1, Vit. B2 und Vit. C. Die Ergebnisse werden diskutiert. Bestimmungen von Körpermasse und -länge, Körperzusammensetzung, Hautfaltendicken- und Umfangmessungen, Körperoberfläche, Relativgewicht, Blutdruck und Sitzpulsfrequenz ergänzten die Untersuchungen. Weiterhin wurden die Mahlzeitenfrequenz sowie der individuelle Energiebedarf je Tag der Probanden mittels Arbeitsablaufstudien fortlaufend bestimmt. An Energie nehmen die Frauen im Durchschnitt je Tag 2020±611,3 kcal mit Kostform N, 1970±592,4 kcal mit Kostform L auf. Daraus folgt eine Energiebedarfsdeckung von 103% in der N-Periode, von 99% in der L-Periode. Die Energie setzt sich zusammen aus 14% Protein, 36,4% Fett und 49,6% Kohlenydraten in der Periode L, in der Periode N 13,6% Eiweiß, 39,6% Fett, 44,7% Kohlenhydraten sowie 2,1 % Alkohol.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 31
    Digitale Medien
    Digitale Medien
    Springer
    European journal of nutrition 26 (1987), S. 52-55 
    ISSN: 1436-6215
    Schlagwort(e): blood glucose ; plasma insulin ; milk ; low-lactose milk ; Blutglukose ; Plasmainsulin ; Milch ; laktosearm
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft , Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung An gesunden freiwilligen Versuchspersonen wurde die Reaktion des Blutglukosespiegels und der Plasmainsulinkonzentration auf Test-Milchproben untersucht. Nach Fasten über Nacht bekamen die Versuchspersonen 500 ml einer gewöhnlichen fettfreien Milch (ca. 25 g Laktose) oder 500 ml einer neuen laktosearmen, fettfreien Milch (3,75 g Laktose und 4,25 g Fruktose). Die Blutglukosespiegel wurden durch keine der beiden Milchproben signifikant erhöht, aber die Plasmainsulinkonzentration erhöhte sich nach der Milchzufuhr signifikant. Diese Reaktion war nach der gewöhnlichen fettfreien Milch geringfügig, aber nicht signifikant höher als nach der neuen laktosearmen, fettfreien Milch. Die Ergebnisse zeigen, daß fettfreie Milch keine rasche Wirkung auf die Konzentration der Blutglukose ausübt und daß deshalb fettfreie Milch, insbesondere solche mit geringem Laktosegehalt, auch für die Diabetesdiät geeignet ist.
    Notizen: Summary The blood glucose and plasma insulin responses to test milk samples were studied in healthy normal volunteers. After an overnight fast the subjects were given 500 ml of either regular fat free milk (∼ 25 g lactose) or 500 ml of a new low-lactose fat free milk (3.75 g lactose and 4.25 g fructose). Blood glucose levels were not significantly altered after either milk sample, but plasma insulin responses were significantly elevated after milk consumption. The response was slightly but not significantly higher after regular fat-free milk than after the low-lactose fat free milk. The results suggest that fat free milk does not exert a fast effect on blood glucose concentration and therefore fat free milk and especially low-lactose fat free milk may prove to be suitable for diabetic diets.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 32
    Digitale Medien
    Digitale Medien
    Springer
    European journal of nutrition 26 (1987), S. 62-72 
    ISSN: 1436-6215
    Schlagwort(e): Eiweiß-Fett-Komplexe ; Fettoxidation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft , Medizin
    Beschreibung / Inhaltsverzeichnis: Summary It was tried in model experiments to explain some phenomena of the mutual influence of fats and proteins by analyzing protein-fat complexes as well as the influence of meat protein on the dynamics of fat oxidation. Gel of muscle meat and a tissue sample served as meat substrate, methyl esters and oxidation products of linoleic acid as fat substrates. It has been found that meat proteins influence the kinetics of fat oxidation throughout the oxidation process. The tissue sample lowered, with simultaneous change of the process dynamics, the induction time of the methyl-linoleate oxidation by nearly half. The extent of effect of the products of the methyl linoleate oxidation on the muscle gel proteins depended on changes in the protein structure under the influence of technological processes. In muscle gel exposed to thermal treatment, the quantity of stable protein-fat complexes increased.
    Notizen: Zusammenfassung In Modellexperimenten wurde versucht, einige Erscheinungen der gegenseitigen Beeinflussung von Fetten und Eiweißen zu erklären. Dabei wurde das Vorliegen von Eiweiß-Fett-Komplexen sowie der Einfluß von Fleisch-Eiweiße auf die Dynamik der Fettoxidation analysiert. Fleischsubstrat war ein Muskelgel- und ein Bindegewebspräparat. Als Fettsubstrat dienten der Methylester der Linolsäure und Produkte seiner Oxidation. Es wurde festgestellt, daß Fleischeiweiße die Kinetik der Fettoxidation in allen Abschnitten dieses Prozesses beeinflussen. Das Bindegewebe verkürzte bei gleichzeitiger änderung der Verlaufsdynamik die Induktionszeit der Methyllinoleat-Oxidation fast um die Hälfte. Der Umfang der Einwirkung der Produkte der Methyllinoleat-Oxidation auf Muskelgel-Eiweiße war von änderungen der Struktur dieser Eiweiße unter Einfluß technologischer Verfahren abhängig. In dem der Wärmebehandlung unterzogenen Muskelgel stieg die Menge stabiler Eiweiß-Fett-Komplexe an.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 33
    ISSN: 1436-6215
    Schlagwort(e): Ernährung beiDiabetes ; Kohlenhydrate ; Fette ; Eiweiß ; Vitamine
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft , Medizin
    Beschreibung / Inhaltsverzeichnis: Summary Forty patients with non-insulin-dependent diabetes mellitus (NIDDM) were investigated regarding their individual diet history, including dietary pattern and dietary habits. The energy intake in men was 2,180±460 kcal/day. The carbohydrate content was 192±57 g/day (38+7 %), protein 93±20 g/day (19+3%) and fat 96±26g/day (43±7%). Nutritional intake of saturated fatty acids was 37±11 g/day, whereas the intake of polyenic acid was 14±5g/day. Thus the p/s-quotient was 0.4±0.1. The cholesterol intake amounted to 396±165 mg/day. The dietary fibre content was 33±21 g/day. The caloric intake of women was 1,800 kcal/day. The daily amount of carbohydrate was 154±46 g/day (37±6%), of protein 82±21g/day (20±4%), of fat 82±32g/ day (43±6%). Saturated fatty acids were 33±14g/day, polyenic acid 11±5g/day, the p/s-quotient 0.4±0.2. The cholesterol intake was calculated to be 341±118 mg/ day. The supply of electrolytes, trace elements and vitamins was often marginal. We found that usually practiced diabetes diet is too fatty, rich in cholesterol and poor in carbohydrate and fibre. As a result of the high amount of fat, which comprises 43% of the total calories and the low p/s-quotient of 0.4, the diet must be considered atherogenic.
    Notizen: Zusammenfassung 20 Frauen und 20 Männer mit nicht insulinpflichtigem Diabetes mellitus wurden hinsichtlich ihrer Ernährungsgewohnheiten untersucht. Die Männer waren im Durchschnitt 54±8 Jahre alt, sie hatten eine Größe von 177±5 cm und ein Körpergewicht von 86±9 kg. Das durchschnittliche Alter der Frauen betrug ebenfalls 54±5 Jahre, die Größe 164±7 cm und das Körpergewicht 83±18 kg. Die durchschnittliche Diabetesdauer lag in beiden Kollektiven bei 7 Jahren. Alle Patienten unterzogen sich freiwillig einer detaillierten Ernährungsanamnese. Bei allen Personen war im Verlaufe ihrer Erkrankung bereits eine Ernährungsberatung durchgeführt worden. Der Blutzucker-Nüchternwert bei der stationären Aufnahme betrug bei Frauen 176±75 mg/dl, bei Männern 149±48 mg/dl. Entsprechend den höheren Blutzuckernüchternwerten lag auch der HbA-1-Wert mit 10,2±2,2 % bei Frauen höher als bei Männern, welcher hier nur 8,9±2,0 % betrug. Die Energieaufnahme betrug bei Männern 2180±460 Kalorien/Tag. Die Männer verzehrten im Durchschnitt 192±57 g Kohlenhydrate (38+7%), 93±20 g Eiweiß (19±3 %) und 96±25 g Fett (43±7%). Die Ballaststoffaufnahme betrug bei Männern 33±21g/Tag. Die Zufuhr von gesättigten Fettsäuren lag bei 37±11 g/Tag, während nur 14±5 g Polyensäuren/Tag verzehrt wurden. Die P/S-Quotient betrug 0,4±0,2. Die Cholesterinaufnahme mit der täglichen Kost wurde mit 396±165 mg bestimmt. Die Frauen verzehrten im Durchschnitt 1800±530 Kalorien. Die Kohlenhydrataufnahme betrug 154±46 g/Tag (37±6%). Der Proteinkonsum lag bei 82±21 g/Tag (20±4%), die Fettaufnahme betrug 82±32 g/Tag (43±6%). Die Zufuhr von gesättigten Fettsäuren mit der Nahrung lag bei 33±14g/Tag, die von Polyensäuren nur bei 11±5g/Tag. Der P/S-Quotient lag bei 0,4±0,2. Die Cholesterinaufnahme mit der Nahrung wurde mit 341±118 mg/Tag berechnet. Eine marginale Versorgung für Elektrolyte, Spurenelemente und Vitamine wurde häufig gefunden. Geordnet nach der Reihenfolge ergab sich eine unzureichende Versorgung bei den Männern für die Pantothensäure (75%), für Vitamin D (70%) und für Folsäure (60%). Bei Frauen hatten 90% eine marginale Versorgung für Folsäure, 85% eine Unterversorgung von Pantothensäure und 80% eine Unterversorgung für Vitamin D. Die derzeit praktizierte Diabetes-Diät kann als fettreich, cholesterinreich und kohlenhydratarm sowie ballaststoffarm bezeichnet werden. Wegen des hohen Fettanteils von 43% der gesamten Kalorien und des ungünstigen Fettsäuremusters muß sie als atherogen bezeichnet werden.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 34
    Digitale Medien
    Digitale Medien
    Springer
    European journal of nutrition 26 (1987), S. 161-164 
    ISSN: 1436-6215
    Schlagwort(e): dietary glycine ; dietary casein ; serum cholesterol ; liver cholesterol ; rats
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft , Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Im allgemeinen verursachen Diäten, die Kasein enthalten, höhere Serumcholesterinkonzentrationen bei Ratten als Diäten mit Sojaeiweiß. Es wurde postuliert, daß dieser Effekt zumindest teilweise auf den relativ niedrigen Glycinanteil des Kaseins im Vergleich zu Sojaeiweiß zurückzuführen ist. Diese Hypothese wurde getestet, indem einer halbgereinigten Diät mit Kasein Glycin zugefügt wurde, so daß die Glycinkonzentration hier ähnlich war wie in der Diät mit Sojaeiweiß. Die Zugabe von Glycin hatte keinen Effekt auf die durch Kasein induzierten Serum- und Lebercholesterinkonzentrationen bei Ratten. Als Schlußfolgerung ergibt sich, daß der niedrige Anteil an Glycin im Kasein für den hypercholesterinämischen Effekt dieses Eiweißes keine Rolle spielt.
    Notizen: Summary Generally, diets containing casein induce higher concentrations of serum cholesterol in rats than diets containing soybean protein. It has been suggested that at least part of this effect is due to the relatively low level of glycine in casein, when compared to soybean protein. We have tested this suggestion by adding glycine to a semipurified casein diet, so that the level of glycine was similar to that in a diet containing soy protein. The addition of glycine did not affect the casein-induced concentrations of cholesterol in serum and liver of rats. We conclude that the low proportion of glycine in casein does not play a role in casein-induced hypercholesterolemia.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 35
    ISSN: 1436-6215
    Schlagwort(e): Glucose ; Glucosepolymere ; Blutglucosespiegel ; Seruminsulin-spiegel
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft , Medizin
    Beschreibung / Inhaltsverzeichnis: Summary The small intestines of anaesthetized rats were perfused in situ for 60 min with 0.5 % solutions of glucose, maltose, sucrose, maltodextrin DE 20, maltodextrin DE 5 or starch. Blood samples were repeatedly taken from the v. portae and the v. femoralis to estimate blood glucose and serum insulin levels as a function of perfusion time. The experiment was also performed to clarify whether a correlation exists between these parameters and the substrate uptake from the intestinal lumen (determined in the first part of the study). The highest glucose levels in v. portae and the highest portal-peripheral differences were found when glucose and maltose solutions were administered. Glucose levels in v. femoralis were almost independent of the substrate perfused. Perfusion with glucose caused a considerable insulin secretion starting immediately with the onset of perfusion. It was concluded that glucose might also stimulate insulin secretion on the intestinal level. Perfusion with maltose also effected a significant insulin output, the start of which was delayed however, compared with the effect of glucose.
    Notizen: Zusammenfassung Der in situ belassene Dünndarm von narkotisierten Ratten wurde mit 0,5%igen Lösungen von Glucose, Maltose, Saccharose, Maltodextrin DE 20, Maltodextrin DE 5 und Stärke 60 Minuten lang perfundiert. Durch mehrmalige Entnahme von Blutproben aus der V. portae und V. femoralis wurde die zeitabhängige Änderung der Blutglucosespiegel und der Seruminsulinkonzentration bestimmt. Es sollte geklärt werden, inwieweit zwischen diesen Parametern und der Aufnahme der Substrate aus dem Darmlumen (die im ersten Teil der Untersu-chungsserie beschrieben wurde) eine Korrelation besteht. Die höchsten Glucosespiegel in der V. portae und die größten portal-peripheren Differenzen wurden bei Perfusion mit Glucose- und Maltoselösungen registriert. Die Glucosekonzentration in der V. femoralis unterschied sich bei Angebot der verschiedenen Substrate kaum. Die Perfusion mit Glucose bewirkte eine erhebliche, sofort einsetzende Insulinsekretion. Hieraus wird geschlossen, daß Glucose die Insulinausschüttung auch auf intestinaler Ebene stimuliert. Auch die Perfusion mit Maltose verursachte eine beträchtliche Sekretion von Insulin, die jedoch im Vergleich zum Effekt der Glucose verzögert einsetzte.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 36
    Digitale Medien
    Digitale Medien
    Springer
    European journal of nutrition 26 (1987), S. 125-137 
    ISSN: 1436-6215
    Schlagwort(e): vitamin C ; functions ; kinetics ; pool ; saturation ; requirements ; RDA
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft , Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Die Bedeutung von Vitamin C für den menschlichen Organismus wird aus den wichtigen Funktionen ersichtlich, an denen das Vitamin beteiligt ist, wie zum Beispiel Kollagen- und Karnitinsynthesen. In neuerer Zeit entdeckt wurde seine Rolle bei der Noradrenalinsynthese, der Inaktivierung von freien Radikalen sowie der Verhinderung der Nitrosaminbildung. Die Vielfalt dieser Vitamin-C-abhängigen Funktionen läßt erkennen, daß die Bedarfsfestsetzung für Vitamin C nicht nur die Verhütung der Mangelkrankheit Skorbut anvisieren, sondern auch berücksichtigen sollte, daß alle diese Funktionen jederzeit genügend Vitamin C zur Verfügung haben müßten, um optimal reagieren zu können. Das Konzept der Gewebesättigung kommt diesem Ziel am nächsten. Studien mit einem kinetischen Modell haben ergeben, daß eine Sättigung mit täglicher Einnahme von 100 mg Vitamin C bei Nichtrauchern und von 140 mg bei Rauchern eintritt, Mengen, die als optimale Werte gelten können. Bei verschiedenen Krankheiten dürfte der Bedarf höher sein; die genauen Mengen müssen jedoch erst noch ermittelt werden.
    Notizen: Summary The importance of vitamin C is reflected in its multifunctional roles which include participation in collagen and carnitine syntheses, promotion of iron absorption and the more recently discovered participation in noradrenaline synthesis, inactivation of free radical chain reactions, prevention of N-nitroso compound formation and more. Given the many extra-antiscorbutic functions of the vitamin, the Recommended Dietary Allowances (RDA) should not just prevent deficiency disease but should aim at providing sufficient amounts for all vitamin C-dependent functions to operate at full capacity. The concept of vitamin C tissue saturation is best able to meet this demand. The use of kinetic models has shown that the body pool is saturated with a daily intake of 100 mg vitamin C in non-smokers and 140 mg in smokers, amounts that may be regarded as optimal RDA values. Certain disease states may be accompanied by still higher vitamin C requirements but the exact amounts are not yet known.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 37
    Digitale Medien
    Digitale Medien
    Springer
    European journal of nutrition 26 (1987), S. 143-157 
    ISSN: 1436-6215
    Schlagwort(e): Colonkrebs ; Epidemiologie ; Ernährung ; Ätiologie
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft , Medizin
    Beschreibung / Inhaltsverzeichnis: Summary Colon cancer is one of the most frequent forms of cancer in the Federal Republic of Germany and in most Western countries, but is, however, generally rare in Africa, Asia, and Latin America. Based on epidemiological investigations, differing dietary practices are considered to be main reason for these differences. A high fat and protein consumption was identified as a risk factor, while a high fibre content of the diet was found to be protective. Existing hypotheses of the etiology of colon cancer, which are based on the two-stage initiation-promotion model, regard interactions between initiators, promotors, and inhibitors as decisive for the final outcome of colon cancer. Possible initiators are pyrolysis products of protein-rich food (meat or fish), generated by heating, and products of metabolism of intestinal bacteria (e.g. faecal mutagens, N-nitroso compounds, transformation products of bile acids). Fats probably exert their influence only at the promotional stage. The diet-dependent bacterial formation of deoxycholic and lithocholic acids is a possible mechanism which has been experimentally substantiated. The protective effect of a diet rich in fibre seems to be mediated in particular by dilution and adsorption of harmful compounds. Further protective factors in human diet may be calcium, selenium, vitamin A and β-carotene. In this paper, evidence, both supporting and refuting the existing hypotheses, is discussed, as well as the possibilities of dietary prevention of colon cancer.
    Notizen: Zusammenfassung Der Colonkrebs ist eine der häufigsten Krebserkrankungen in der Bundesrepublik Deutschland und in den meisten westlichen Ländern, in Afrika, Asien und Lateinamerika jedoch gewöhnlich selten. Aufgrund epidemiologischer Untersuchungen sind verschiedenartige Ernährungsgewohnheiten die Hauptursache für diese Unterschiede. Ein hoher Fett- und Eiweißkonsum wurde als Risikofaktor erkannt, während ein hoher Ballaststoffgehalt der Nahrung sich als protektiv erwies. Die existierenden Hypothesen zur Ätiologie des Colonkrebses, die vom „Zwei-Stufen-Initiations-Promotionsmodell“ ausgehen, betrachten das Wechselspiel der Einwirkung von Initiatoren, Promotoren und Inhibitoren als entscheidend für die Realisierung des Colonkrebses. Als Initiatoren kommen Pyrolyseprodukte in Frage, die beim Erhitzen proteinreicher Lebensmittel (Fleisch, Fisch) entstehen, sowie Stoffwechselprodukte von Darmbakterien (fäkale Mutagene, N-Nitrosoverbindungen, Transformationsprodukte von Gallensäuren). Fette wirken wahrscheinlich nur auf der Promotionsebene ein. Die ernährungsabhängige bakterielle Bildung der Desoxy- und Lithocholsäure ist ein möglicher, experimentell belegter Mechanismus. Der Schutzeffekt einer ballaststoffreichen Ernährung dürfte insbesondere auf einer Verdünnung und Adsorption von Schadstoffen beruhen. Als weitere protektive Faktoren der menschlichen Nahrung gelten Calcium, Vitamin A, β-Carotin und Selen. In dieser Arbeit werden die Belege diskutiert, die den existierenden Hypothesen zugrunde liegen, und die Möglichkeiten zur diätetischen Prävention des Colonkrebses erörtert.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 38
    Digitale Medien
    Digitale Medien
    Springer
    Journal of plant growth regulation 5 (1987), S. 169-173 
    ISSN: 1435-8107
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Phytohormone effects on cell division of synchronous cultures ofChlorella pyrenoidosa (TX-7-11-05) were studied under different photo flux densities. The time required for initiation of incipient cell division was reduced significantly by treatment with kinetin (6-furfurylaminopurine), gibberellic acid, and indole-3-acetic acid. Data show that kinetin was more effective than gibberellic acid, which was more effective than indole-3-acetic acid. Studies with combinations of the phytohormones revealed no antagonistic, additive, or synergistic effects.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 39
    Digitale Medien
    Digitale Medien
    Springer
    Journal of plant growth regulation 5 (1987), S. 163-167 
    ISSN: 1435-8107
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Root collars of white ash (Fraxinus americana L.) and black walnut (Juglans nigra L.) were drenched in April with wettable powder formulations containing 2, 4, or 12 g of flurprimidol {α-(1-methylethyl)-[4-(trifluoromethoxy)phenyl]-5-pyrimidinemethanol} or paclobutrazol [(2RS, 3RS)-1-(4-chlorophenyl)-4,4-dimethyl-2-(1,2,4-triazol-1-yl)-pentan-3-ol)] to determine shoot growth inhibition and the soil location of residual activity. By the end of the first growing season, black walnut shoots were inhibited by all doses of flurprimidol or paclobutrazol. Growth inhibition of black walnut was dramatic (〈50% the growth of control) during the second season with a linear positive response to increasing flurprimidol doses. White ash growth was inhibited by flurprimidol but not paclobutrazol. Flurprimidol activity was concentrated within 10 cm of the treated root collar 1 1/2 years after treatment, which is evidence that the root collar and adjacent roots were the major avenues to the vascular system.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 40
    Digitale Medien
    Digitale Medien
    Springer
    Journal of plant growth regulation 5 (1987), S. 181-181 
    ISSN: 1435-8107
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 41
    Digitale Medien
    Digitale Medien
    Springer
    Journal of plant growth regulation 5 (1987), S. 191-205 
    ISSN: 1435-8107
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract The endogenous levels of abscisic acid in the parasitic phanerogamsArceuthobium oxycedri (DC) Bieb.,Cassytha filiformis L.,Lathraea squamaria L.,Melampyrum pratense L.,Orobanche hederae Duby., andViscum album L. were investigated. In general, the content of abscisic acid was high in parasites which deprive their hosts of both phloem- and xylem-transported substances and much lower in those that deprive their hosts of sap from the xylem only. Within the parasites studied in more depth (e.g.,Orobanche hederae, Lathraea squamaria, andMelampyrum pratense) the highest abscisic acid levels were found in their sink regions, especially in their inflorescences. It is suggested that a high concentration of abscisic acid is associated with plant tissues showing a high demand for phloem-transported substances. The possible role of abscisic acid in such tissues is discussed.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 42
    Digitale Medien
    Digitale Medien
    Springer
    Journal of plant growth regulation 5 (1987), S. 225-234 
    ISSN: 1435-8107
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Addition of surfactant I (trimethylnonylpolyethoxyethanol) or surfactant II (4-isopropenyl-1-methyl-cyclohexane) at 1.0 and 0.6% (v/v) of the spray solution enhanced the phytotoxicity of clopyralid (3,6-dichloro-2-pyridinecarboxylic acid), the triethylamine salt of triclopyr {[(3,5,6-trichloro-2-pyridinyl)oxy]acetic acid}, picloram (4-amino-3,5,6-trichloro-2-pyridinecarboxylic acid), and 2,4,5-T [(2,4,5-trichlorophenoxy)acetic acid)] applied at 0.14 kg ae/ha to greenhouse-grown honey mesquite (Prosopis glandulosa Torr.). Application of benazolin [4-chloro-2-oxo-3(2H)-benzothiazolacetic acid] increased the phytotoxicity of all herbicides, but ethephon [(2-chloroethyl)phosphonic acid] and mefluidide {N-[2,4-dimethyl-5-[[(trifluoromethyl)sulfonyl]amino]phenyl]acetamide} were usually ineffective. Clopyralid + picloram, triclopyr, or 2,4,5-T applied in 1:1 combinations at 0.07 + 0.07 kg/ha were usually equally or more effective than any one of the herbicides applied alone at 0.14 kg/ha. Adjuvants did not enhance the phytotoxicity of picloram, triclopyr, or 2,4,5-T on field-grown honey mesquite but sometimes did with clopyralid.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 43
    Digitale Medien
    Digitale Medien
    Springer
    Journal of plant growth regulation 6 (1987), S. 1-13 
    ISSN: 1435-8107
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Tobacco (Nicotiana tabacum cv White Burley) pollen contains high levels of 1-aminocyclopropane-1-carboxylic acid (ACC; ∼2700 nmol/g). Such large amounts, however, do not appear until very late in the development of the anthers. Washing pollen in Kwacks medium (10% sucrose) removes nearly 40% of the pollen-held ACC. Pollination of isolated styles with washed pollen results in lower ethylene production than that of styles pollinated with unwashed pollen. No reduction in viability of washed pollen was observed in situ, although loss of viability occurred in vitro. Physical wounding of the stylar tissue induced a relatively small increase in ethylene production when compared to that induced by pollination. The results suggest that pollen-held ACC may participate in pollination-induced ethylene production in this species; however, further promotion of ethylene biosynthesis must occur in response to some other factor associated with pollination.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 44
    Digitale Medien
    Digitale Medien
    Springer
    Journal of plant growth regulation 6 (1987), S. 23-32 
    ISSN: 1435-8107
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract White light reduced the efficacy of dimethipin in inducing both desiccation and abscission in kidney beans (Phaseolus vulgaris L. cv. Black Valentine). Moreover, light reduced the previously reported inhibitory effect of dimethipin on protein synthesis (Metzger and Keng 1984) in a way that paralleled the reduction in dimethipin-induced morphological changes. Therefore the inhibition of protein synthesis by dimethipin was the parameter measured in experiments designed to characterize the light-induced reduction of dimethipin efficacy. The light effect was directly proportional to both the fluence rate and the duration of the light treatment. A similar effect of light was observed in cultured kidney bean cells devoid of chlorophyll, ruling out the participation of a photosynthetic related process. Moreover, light had no effect on either the metabolism of [2,3]-14C-dimethipin in kidney bean leaves or uptake of dimethipin into cultured kidney bean cells. No evidence was obtained for photochemical decomposition of dimethipin either. Thus, the light effect is possibly the result of direct modification of the biochemical processes associated with the primary mechanism(s) of dimethipin action, or perhaps promotion of the rate of repair of dimethipin-induced cellular damage.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 45
    Digitale Medien
    Digitale Medien
    Springer
    Journal of plant growth regulation 6 (1987), S. 159-182 
    ISSN: 1435-8107
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Antisera have been raised in rabbits against dihydrozeatin riboside and isopentenyladenosine, and their cross-reactivity characteristics have been examined in detail. These antisera, together with an antiserum previously raised against zeatin riboside, have been employed in radioimmunoassays. Separative procedures that enable a wide range of naturally occurring cytokinins to be separated prior to analysis by radioimmunoassay have been developed. The accuracy with which the following cytokinins can be quantified by our methods, which employ tritiated cytokinin recovery markers, has been estimated: zeatin riboside, zeatin, dihydrozeatin riboside, dihydrozeatin, O-glucosyl zeatin riboside, O-glucosyl zeatin, O-glucosyl dihydrozeatin riboside, O-glucosyl dihydrozeatin, zeatin-9-glucoside, zeatin-7-glucoside, lupinic acid, isopentenyladenosine, and isopentenyladenine.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 46
    Digitale Medien
    Digitale Medien
    Springer
    Journal of plant growth regulation 6 (1987), S. 183-191 
    ISSN: 1435-8107
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Mefluidide [N-2(2,4-dimethyl-5-((trifluoromethyl)sulfonyl)amino)phenyl)acetamide] was applied to winter wheat (Triticum aestivum) to determine the alterations in shoot chemical composition and the value of the changes to a wheat-based forage system in field and controlled-environment chamber experiments. Mefluidide, applied at rates between 0.1 and 0.25 kg/ha during full tiller stage (Feekes stage 4), slowed down the rate of cellulose deposition in wheat shoot and reduced neutral-detergent fiber fractions. Mefluidide decreased the rate of nitrogen decline with advancing maturity of treated plants when compared to untreated ones. Mefluidide also reduced cellulose deposition and maintained high nitrogen contents in regrowth shoot tissues in addition to the effect produced by mechanical defoliation. Mefluidide, applied during jointing stage (stage 5), also retarded wheat maturation as the chemical maintained shoot chemical characteristics equivalent to those of earlier stages of development. Mefluidide did not alter significantly shoot chemical composition when applied at boot stage (stage 10), compared to untreated wheat. Based on the experimental results, mefluidide may be a management tool to alter timing of plant development. The delay in maturation and maintenance of vegetative quality longer into the spring attained with mefluidide may suggest a beneficial role of the chemical in a dual-purpose wheat production system that favors forage utilization.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 47
    Digitale Medien
    Digitale Medien
    Springer
    Journal of plant growth regulation 6 (1987), S. 201-208 
    ISSN: 1435-8107
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract The effects of chilling on ethylene production by leaf discs and whole plants of bean (chilling-sensitive) and pea (chilling-tolerant) were studied. When pea or bean leaf discs were excised and incubated at 25°C, transient increases in ethylene production and 1-aminocyclopropane-1-carboxylic acid (ACC) accumulation were observed. Both pea and bean discs kept at 5°C evolved little ethylene, but levels of ACC increased in pea discs and not in bean discs. When discs of either species were chilled at 5°C immediately after excision and then transferred to 25°C 9 h later, increases in their ACC levels and ethylene production rates were observed. Discs were also incubated at 25°C for 12 h to allow excision-induced ethylene production to subside and then chilled at 5°C. Nine hours later, these discs were transferred to 25°C, and an increase in ethylene production was observed. These data indicate that chilling suppresses excision-induced ethylene production and enhances the production of ethylene after transfer to 25°C. Chilling of whole plants resulted in increased production of ethylene and ACC in the chilling-sensitive bean but not in the chilling-tolerant pea. Treatment of bean plants with the ethylene antagonists silver thiosulfate, norbornadiene, or aminooxyacetic acid, or of pea plants with ethylene, did not affect the appearance of chilling injury symptoms, indicating that ethylene does not induce injury symptoms and may not have an adaptive role in chilling stress.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 48
    Digitale Medien
    Digitale Medien
    Springer
    Journal of plant growth regulation 6 (1987), S. 209-213 
    ISSN: 1435-8107
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Apple trees (Malus domestica Borkh “Spartan” grafted on MM 106 rootstock) planted in 1976 in an orchard at Beltsville, Maryland, were treated with paclobutrazol (2RS,3RS)-1-(4-chlorophenyl)-4,4-dimethyl-2-1,2,4-triazol-1-yl-pentan-3-ol) using a foliage spray in 1982 and by trunk banding in 1983. Paclobutrazol did not inhibit shoot growth in 1983; however, shoot growth was significantly retarded in 1984. Increases in organic acids, including succinic, malic, citric, and quinic, and also in total phenols, occurred in wood produced in 1983 on paclobutrazol-treated trees when growth was not inhibited and in wood produced in 1984 when growth was inhibited. The organic acid content of both paclobutrazol-treated and untreated wood tended to decrease from the winter dormant period through growth resumption in the spring. However, the content of total phenols remained nearly the same throughout this sampling period.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 49
    Digitale Medien
    Digitale Medien
    Springer
    Journal of plant growth regulation 6 (1987), S. 221-232 
    ISSN: 1435-8107
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Root applications of 0.1 μM 6-benzyladenine (BA) and 10.0 μM indole-3-butyric acid (IBA) enhanced or inhibited, respectively, root bud growth in hydroponically grown Canada thistle [Cirsium arvense (L.) Scop.]. Translocation of14C-glyphosate [N-(phosphonomethyl)glycine] into roots was positively correlated with this growth. Foliar applications of ethephon or chlorfluorenol also enhanced root bud growth, but glyphosate translocation was only weakly correlated with such growth in soil-grown Canada thistle. At glyphosate rates above 0.56 kg/ha, root bud growth was not stimulated by plant growth regulators (PGRs) and basipetal translocation was not enhanced. Paradoxically, ethephon and chlorflurenol restrained root bud growth in the field since thistle control steadily improved during the 3 years following treatment.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 50
    Digitale Medien
    Digitale Medien
    Springer
    Journal of plant growth regulation 6 (1987), S. 233-244 
    ISSN: 1435-8107
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Greenhouse nutrient solution studies demonstrated that diniconazole will decrease peanut (Arachis hypogaea L.) shoot growth when either root or shoot applied. Root growth and development were decreased by root and, to a lesser extent, by shoot uptake of diniconazole. Diniconazole is apparently xylem translocated, but not phloem translocated. Concentrations of 200 ppb ES isomer of diniconazole in nutrient solution (root uptake) increased specific leaf weight and starch deposits in the leaf. Field applications of 193 g ES isomer ha−1 of diniconazole reduced main stem height by 33%, leaf area index by 16%, and total vegetative dry weight by 19%, but had no effect on average leaf size. Decreased germination of seeds from plants treated with 1435 g ha−1 diaminozide was associated with increased seed dormancy. Seed dormancy was counteracted by either ethylene gas or storage for 150 days after harvest. Soil applications of diniconazole were more effective than foliar appliations in reducing vine growth. Diniconazole's ER isomer is a broad spectrum fungicide that reduced damage (when compared to the control) bySclerotium rolfsii andRhizoctonia solani. The reduced damage by these diseases was thought to be the primary reason for the significant pod yield increase (when compared to the control) observed with the diniconazole treatments. In drought-stressed plots, populations of the two-spotted spider mite (Tetranychus urticae) were increased by diniconazole.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 51
    Digitale Medien
    Digitale Medien
    Springer
    Agriculture and human values 4 (1987), S. 75-80 
    ISSN: 1572-8366
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Bovine Growth Hormone has been beset by controversy since before its public introduction. The reasons for this are numerous but all rooted in the economic and policy uncertainty surrounding a transitional agriculture. The major sources of the controversy are outlined in this paper as the author explains how little of the ensuing discussion has been based on positive knowledge of either bGH or its likely farm impact. The paper, as a result, raises important questions about the implications of addressing agriculture policy changes in the highly emotionally charged context of present American agriculture.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 52
    Digitale Medien
    Digitale Medien
    Springer
    Agriculture and human values 4 (1987), S. 54-55 
    ISSN: 1572-8366
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 53
    Digitale Medien
    Digitale Medien
    Springer
    Agriculture and human values 4 (1987), S. 27-41 
    ISSN: 1572-8366
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract The current problems of rural people and communities expose the weakness of the social sciences in agriculture, both as to epistemological limitations and as to the environment in which they operate. That weakness involves not ony an inability to make reasonably accurate predictions, but also to explain scientifically the nature of the current situation. This conclusion is reached after an examination of the context of the current problems of rural America, an evaluation of the epistemological capabilities of the relevant social sciences, and an appraisal of the environment in which the social sciences within agriculture exist. An over-allocation of resources to the economics of commercial agriculture and an under-allocation to the other social sciences and the economics of rural development is suggested as a serious problem. Significant reallocation of resources will be required if the traditional agricultural establishment is to remain relevant to rural people and their needs.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 54
    Digitale Medien
    Digitale Medien
    Springer
    Agriculture and human values 4 (1987), S. 42-65 
    ISSN: 1572-8366
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract This paper seeks to provide a broad overview of the historical, contemporary, and future roles of the rural social sciences. This overview is preceded by a brief elaboration of a model of the social, political, and economic structure of experiment station research organizations which is helpful in identifying the particular types of agricultural and social sciences research that have tended to be conducted in land-grant institutions. Agricultural economics and rural sociology are given particular emphasis in the next section of the paper which discusses the history and current state of the rural social sciences as disciplines. The prospective roles of five “nontraditional” rural social sciences—history, anthropology, political science, geography, and philosophy—in land-grant research programs are also discussed. The final sections of the paper assess major problems in, and recommended solutions for bolstering, the role of the social sciences in the land-grant system.
    Materialart: Digitale Medien
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  • 55
    Digitale Medien
    Digitale Medien
    Springer
    Agriculture and human values 4 (1987), S. 1-3 
    ISSN: 1572-8366
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 56
    Digitale Medien
    Digitale Medien
    Springer
    Agriculture and human values 4 (1987), S. 81-92 
    ISSN: 1572-8366
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 57
    Digitale Medien
    Digitale Medien
    Springer
    Agriculture and human values 4 (1987), S. 4-26 
    ISSN: 1572-8366
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Written as a contribution to the Social Science Agricultural Agenda Project, this essay in historical interpretation assumes that the main contribution that historians can make to the planning process is to describe and explain how the situation facing the planners came to be. Organized around three concepts—Jeffersonian or democratic agrarianism, the Great American Agricultural Revolution, and the farm crisis of the 1980s, the main implication of the paper may be that Jeffersonianism, once so filled with promise, now gets in the way of realistic thinking about farming and rural life. To implement agrarian values in existing circumstances, we would need to do more than end the crisis. We would need to move back against the revolution.
    Materialart: Digitale Medien
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    Agriculture and human values 4 (1987), S. 66-74 
    ISSN: 1572-8366
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract the personality of the farm sector is basically healthy and has many of the favorable attributes embodied in the image of the family farmer as self-reliant and independent; and as committed to fair play, due process, and democratic ideals. But a darker side of the farm personality traits has emerged in the course of American history. Social scientists for the most part have given little attention to negative personality traits of farmers and the goals, values, and beliefs that underlie these negative traits. The purpose of this essay is to address the issue. The conclusion is that social scientists must confront myths that may have made life tolerable for many farmers but also have provided a psychological and ideological climate where paranoia, scapegoating, violence, armed confrontation, intimidation, and fear reflect the dark side of the farm personaility.
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  • 59
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    Agriculture and human values 4 (1987), S. 1-3 
    ISSN: 1572-8366
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
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    Agriculture and human values 4 (1987), S. 93-96 
    ISSN: 1572-8366
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
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  • 61
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    Agriculture and human values 4 (1987), S. 4-10 
    ISSN: 1572-8366
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract The deepening U.S. farm crisis has been accompanied by numerous benefit fund raisers, individual donations and volunteer programs—all an expression of cooperation and concern on the part of U.S. citizens, farmer and non-farmer alike. These responses have received wide media attention and much public praise. A sense of patriotism and self-reliance underlies their popularity. Nevertheless, such efforts work to undermine their own ultimate objective—that of improving the economic circumstances of the family farm and farm family. This irony, it is argued, arises from the fact that these charitable responses typically depoliticize the nature of the U.S. farm crisis. First, they deflect public attention away from the larger economic context and the structural inequities within it. Second they revitalize agrarian-based myths which serve to rationalize and to reproduce the ‘independent’ behavior of small, commercial farmers. Finally, it is argued that the depoliticization of the farm crisis is itself a political strategy, one which supports and legitimizes ‘business as usual’ and is compatible with the interests of corporate agriculture.
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  • 62
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    Agriculture and human values 4 (1987), S. 40-46 
    ISSN: 1572-8366
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract The paper examines the social contradictions generated by patterns of reproduction of accumulation of capital, social legitimation and by present agricultural policies fostered by the State. Through a scrutiny of the role of the State in capitalism it is argued that agricultural overproduction, the widening of the gap between small and large farms, the fiscal crisis of the State associated with agricultural programs and waste of resources are the outcomes of an attempt on the part of the State to promote simultaneously accumulation and legitimation. The possibility of enhancing accumulation and maintaining legitimation clashes with the diverse socio-economic demands associated with the present agricultural production system and the general viability of the social structure as a whole.
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  • 63
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    Agriculture and human values 4 (1987), S. 11-28 
    ISSN: 1572-8366
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Two major episodes of farm protest have occurred in the past decade. In each case, protesting farmers have chosen to create new farm organizations rather than express their grievances through one of many existing farm interest groups. The result has been the development of a durable grassroots farm lobby, a hybrid mode of exercising political influence that combines features of interest group lobbying and social movement protest. The first episode saw the mobilization of the American Agriculture Movement (AAM), a nation-wide protest organization devoted to achieving a federal guarantee of parity prices. When AAM's attempt to change federal farm policy failed, it was unable to sustain a high level of member mobilization or organizational activity. This failure is attributed to the lack of a stable organizational structure, the lack of durable membership incentives, and the counterproductive effects of disruptive protest tactics. The second episode of protest occurred in reaction to the farm-debt crisis of the 1980s. Protesting farmers organized numerous crisis groups to provide emergency services to financially distressed farmers. The crisis groups coalesced into the National Save the Family Farm Coalition (NSFFC) in order to exert influence over federal farm policy. It is argued that this coalition structure, along with membership incentives provided by crisis groups through their constituent service programs, may allow this latest farm movement to exert more considerable and durable influence over federal farm policy than AAM was able to do in the late 1970s. The problems of maintaining a national coalition of grassroots groups are discussed and evaluated.
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  • 64
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    Agriculture and human values 4 (1987), S. 29-39 
    ISSN: 1572-8366
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract As a result of financial difficulties confronting American agriculture, public debate is focusing on longterm options for restoring economic stability and growth to the agricultural economy. Many believe that just as homeowners in small communities throughout the nation have been served by the development of a secondary market for residential mortgages sponsored by the federal government, farmers throughout the country would similarly benefit from the development of a secondary market for farm real estate mortgages. This paper discusses issues relating to the development of a secondary market for agricultural real estate loans. The concept of a secondary market for agriculture is of considerable interest to Congress, as evidenced by recent enactment of the Agricultural Credit Act of 1987 which established the Federal Agricultural Mortgage Corporation (“Farmer Mac”) to create a secondary market for farm real estate loans. The first section discusses the general nature of secondary markets and their purposes, with particular attention given to the secondary market for home mortgages because it served as a model for a secondary market for farm loans. Section two discusses basic differences between agriculture and housing, and section three provides a brief discussion of federal credit subsidies designed to help meet social and economic goals by influencing the allocation of credit to particular sectors of the economy such as housing and agriculture. Potential benefits and costs associated with the development of a secondary market for agriculture are discussed in section four.
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    Agriculture and human values 4 (1987), S. 47-52 
    ISSN: 1572-8366
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Is it possible to avoid “the agrarian myth” while recognizing the genuine value—which is not necessarily the economic or monetary value—of agrarian pursuits? My answer is that such a recognition of genuine agrarian values is possible, but only if we recapture a lost sense of the value of productive activities generally.An impediment to this recognition, I maintain, is modern economics—both socialist and free market; one important means to it, the natural law philosophy of the eighteenth century French Physiocrats.
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    Agriculture and human values 4 (1987), S. 94-99 
    ISSN: 1572-8366
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
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  • 67
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    Agriculture and human values 4 (1987), S. 53-64 
    ISSN: 1572-8366
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Marxist social scientists have argued that the relationship between social and technical change is one of mutual interaction; innovation in the modes of production affects social organization, and social organization, in turn, has an impact on the development of novel modes of production. This consideration is of fundamental importance for the construction of any economic development policy. However, analyses of this critical relationship have been elaborated within a conceptual framework which most social scientists and policy makers who work within the framework of neoclassical economic thought find difficult to understand. When marxists argue that technical innovations are the product of a class conflict, non-marxist social scientists are left wondering about what the exact meaning of such a statement. Because marxists have been unable to communicate their message, their important insights into the relation between social and technical change have not been incorporated in contemporary development policy; this situation has often resulted in great social costs. In the past fifteen years, however, Yujiro Hayami and Vernon Ruttan have attempted to analyze the critical interaction of social and technical change using neo-classical economic concepts. I argue that their approach can be utilized to express marxist insights in a language accessible to non-marxist social scientists. The careful and critical adoption of this approach could provide the grounds for a more fruitful dialogue about the interaction of social and technical change, and aid the construction of a new development policy.
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    Agriculture and human values 4 (1987), S. 65-75 
    ISSN: 1572-8366
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Roman agriculture suffered traumatic changes during the 2nd century B.C. The traditional farmers who tilled their few acres and served family, gods and community were being squeezed out by large estate owners using slaves for investment farming. Politicians, scholars and poets tried to revive the ancestoral rustic life. In 133 B.C. the Gracchi legislated land reform to relieve the distress of the farmer soldiers who had won the empire. Although their efforts led to political confrontation that deteriorated into civil war, programs for the traditional farm became a permanent part of government policy from the late Republic until the end of the empire in 476 A.D. Scholars and poets made a contribution to the revival of agriculture with knowledge for improving the farm and by encouraging an agrarian mentality. The agricultural manuals (e.g. Cato (c. 150 B.C.), Varro (c. 50 B.C), and Columella (c.65 A.D.), defined the nature of the desirable farm and gave practical advice. Profit was the goal, but good farming practices made for pleasure and virtue as well. The image of the ancestoral farmer was perpetuated as was the notion that farming was the only honorable and respectable occupation for a Roman gentleman. In the Augustan Age (34 B.C.—14 A.D.) poets were encouraged by the government to adopted a rustic theme in hopes it would stimulate a return to the land and aid in the rebirth of Rome and Romans. In the GeorgicsVirgil begins with the practical details of farming, but uses myth and philosophy to explore the nature and meaning of life. He admits that Jove made life perilous. But Jove also gave man the art of agriculture and with hard work man could know the pleasure of a simple, virtuous, productive life. Horace directed his poetry against the allure of city life and in praise of rustic living. Epicureanism and Stoicism, in the guise of life on the farm, could show that although fate was unpredictable, the world was orderly and, if one recognized and accepted its limits, one could make a garden of the world and live a simple but happy life. By 300 A.D. Rome missed the peasant-farmer-soldier and by the 470's life had returned to an agrarian condition. Bishop Sidonius, trying to furnish meaning and perspective for the emerging new age, resorted to the Roman agricultural traditions still cherished as that world disappeared.
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    Agriculture and human values 4 (1987), S. 76-93 
    ISSN: 1572-8366
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Through an interdisciplinary approach, I attempt to construct a partial ethno-agronomy of the Seneca people in late pre-contact times and examine it for relevance to modern agriculture. Diohe'ko, the Three Sisters, had been cultivated for at least five hundred years prior to contact by the Seneca, an Iroquoian tribe inhabiting western New York State. The Three Sisters, corn, beans and squash (pumpkins, gourds), were planted together in hills in fields, cultivated and harvested by work parties of women. Changes of village sites and patterns of village movement respond to the adoption of agriculture as well as other factors. Evaluating land use, crop yields and carrying capacity, I question the accuracy of Seneca population estimates. The Three Sisters was an important cultural complex. The Sisters are protagonists of a number of Seneca tales, myths, ceremonies and legends. As an agricultural strategy, Three Sisters embodies several efficiencies in growth patterns, nutrient, solar and water use, harvest and nutritional use. Microhabitat manipulation was practiced by the Seneca. The plants exhibit a high degree of cooperation, or commensality, in the association. Some preliminary judgments can be made about specific varieties of the Sisters in use among the Seneca prior to contact. Northern Flint Corn, Cutshort or Cornhill Beans, and Cucurbita pepo such as Crookneck Squashes are likely the eldest varieties in the area. Three Sisters agriculture demonstrates qualities of permanence and sustainability, especially as related to the Seneca cultural fabric. A conservative ethic, like Handsome Lake's teaching, it binds together people in culture and people and nurture in nature. Mary Jemison, who farmed both the colonial and Three Sisters ways, seems to have favored the latter's “leisurely” approach.
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    Agriculture and human values 4 (1987), S. 105-110 
    ISSN: 1572-8366
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
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  • 71
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    Agriculture and human values 4 (1987), S. 1-3 
    ISSN: 1572-8366
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
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  • 72
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    Agriculture and human values 4 (1987), S. 111-136 
    ISSN: 1572-8366
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
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  • 73
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    Agriculture and human values 4 (1987), S. 100-104 
    ISSN: 1572-8366
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract This article is a response to Paul Thompson's recent claim that individual farmers cannot have obligations to practice sustainable methods unless a large number of other producers also use them. Using a moral rights framework, I explain the relation of human interests and needs to the duties of individuals to accomplish moral social goals; i.e., those moral goals whose accomplishment requires the cooperation of other persons. The purpose is to show that individual action to promote sustainability does have moral value. Duties to practice sustainable methods are derived from the rights of all persons to adequate food and nutrition. These rights themselves are grounded, not in individual subjective desires or preferences, but in the genuine interests all persons (present and future) have in the satisfaction of basic biological needs to sustain life and health. The duty of each person is correlative to the rights of the others, and fulfillment of the duty requires social action, in this case practicing sustainable methods in farming. If others are unwilling or constrained from fulfilling their obligations, then duties to take other kinds of actions may be derived from the primary duty to attain the goal of sustainability. Actions to secure social cooperation may include, for example, exhorting others to participate and taking political action to force restructuring of agricultural policy, as well as practicing sustainable methods on one's own farm. While frameworks of individual responsibility have been attacked as failing to capture the moral importance of holistic outcomes, it is argued that such problems are related to human motivation rather than to the structure of our moral systems. I conclude that a properly elaborated system of moral rights and duties connected with an adequate moral psychology can account for our duties to other humans to accomplish the goal of a sustainable agriculture.
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  • 74
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    Agriculture and human values 4 (1987), S. 4-14 
    ISSN: 1572-8366
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract The Hatch Act of 1887 was passed in the effort to make agriculture more scientific and efficient. This promise has been seriously compromised by the fact that even research of the highest quality often has limited applicability in practical farming situations. This paper attempts to provide philosophical explanations why this is so by introducing and discussing theoretical models. Consideration is given to why Farming Systems Research does not provide a solution to the philosophical problems raised. The final section presents a strategy for partially avoiding some of the limitations in practical applicability of agricultural research studies and discusses how this strategy relates to the activities of the cooperative extension services. A secondary concern of the paper is with how governmental research priorities compromise the practical applicability of research in farming situations.
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  • 75
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    Agriculture and human values 4 (1987), S. 15-25 
    ISSN: 1572-8366
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract The use of pesticides is one of the more controversial of public issues. This is so because their very widespread use produces immediate benefits to a small section of society, the agricultural industry, while the long term risks are shared by society as a whole. This discussion focuses on the contrast between benefits and risks and outlines some of the long term ecological problems that have resulted from the overuse, misuse, and injudicious use of pesticides. Detailed discussion is provided for such ecological disasters as insect pest resistance to pesticides, pest resurgences and the development of secondary pests; together with contamination of food webs and general ecotoxicity. It is concluded that implementation of integrated pest management (IPM) tactics provides the only practical answer to the manifold problems arising from the sole reliance on pesticides for pest control. IPM provides an ecological oriented strategy for pest control that can maximize the benefits of pesticide use and minimize the risks.
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  • 76
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    Agriculture and human values 4 (1987), S. 26-31 
    ISSN: 1572-8366
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Based on the assumption that agricultural technologies were available and that the problem was their dissemination and adoption, U.S. development efforts have focused on establishing public-sector extension systems for farmers in developing countries. Evaluations of government extension services in developing countries, however, have found them to be largely ineffective, especially in helping small farmers. As a result, private-sector extension is increasingly receiving attention as an alternative approach. This paper examines various characteristics of public- and privatesector extension, drawing on both the literature and a case study of government extension and farm input stores in Imbabura province, Ecuador. It concludes with a discussion of the implications of increased privatization of extension.
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  • 77
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    Agriculture and human values 4 (1987), S. 43-46 
    ISSN: 1572-8366
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract In the Winter 1987 edition of AHV, Luther Tweeten characterized the farm sector as personality. In that article, Tweeten addressed the dark side of that personality as it has been manifested through recent farm protest. This is a rejoinder. Its intent is to look more deeply at the farm personality and, by so doing, reject dark personality traits as the sole basis for farm activisim and ideology. The article suggests that there are two distinct personalities, one directed toward power and leadership and another disaffected and tempered to follow any mythology. The conclusion is that social scientists must not only confront myths but also confront displays of power that use myths for political gain.
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    Agriculture and human values 4 (1987), S. 32-42 
    ISSN: 1572-8366
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Constraints on the expansion of western water supply projects have turned the attention of urban water developers to market purchases of agricultural water supplies as a source of new water. The conventional wisdom of natural resource economics suggests that such shifts should have minimal impact on the agricultural area-of-origin, promote efficiency in water use, and provide an inexpensive and environmentally preferable alternative to building more dams and reservoirs. However the concentration of urban demand combines with water-extensive irrigation practices in western agriculture and a characteristically bipolar economic and social structure in western irrigation communities to create a potential for severe stress on rural economies and communities. The adaptation of supply-oriented western water institutions to market-oriented functions has not provided a decision-making context that accounts for costs imposed on rural communities; moreover, historically water-rich rural communities have not evolved a water policy infrastructure capable of responding to stress. Before the promise of low-cost water supply through the market mechanism can be realized, the structural contradictions inherited from the traditional water-management institutions must be faced and dealt with by both rural source regions and urban water importers.
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  • 79
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    Agriculture and human values 4 (1987), S. 47-53 
    ISSN: 1572-8366
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract In “Sector as Personality: The Case of Farm Protest Movements,” Luther Tweeten argues that farm activism is motivated by irrational and dysfunctional traits of the “dark side” of a sector-specific farm personality. In response, this article questions the assumption that movement activism can be explained by reference to a few discrete personality traits, challenges the usefulness of the concept of a sector-specific personality, and disputes the accuracy of Tweeten's attributions of negative traits to all farm movement activists. Evidence is presented to indicate that farm activists are much more diverse in their beliefs and behavior than Tweeten's article portrays them, and it is argued that farm activism is not generally motivated by deluded conceptions of farmers' circumstances and interests.
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  • 80
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    Agriculture and human values 4 (1987), S. 56-73 
    ISSN: 1572-8366
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
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  • 81
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    Journal of chemical crystallography 17 (1987), S. 127-134 
    ISSN: 1572-8854
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geologie und Paläontologie , Physik
    Notizen: Abstract Tetraphenylphthalic anhydride has been structurally characterized by X-ray crystallography: triclinic,P¯1,a=13.386(4),b=13.563(4),c=16.185(6) Å,α=71.70(3),β=109.32(3), λ=116.17(3)°,V=2439(1) Å3,Z=4,D x=1.23 g cm−3,μ=0.73 cm−1,T=295 K, andR=0.065 for 3910 observed reflections. The asymmetric unit consists of two crystallographically independent molecules of tetraphenylphthalic anhydride (TPPA). Crowding from four adjacent phenyl substituents produces large average displacements of the substituents from the central ring (av. ~0.08 Å, max. 0.17 Å) and distortions in the central aromatic ring. The torsion angles relating the plane of the substituent phenyl rings to the central ring plane (av. ∼62°) is consistent with other polyphenylated aromatic structures.
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    Journal of chemical crystallography 17 (1987), S. 153-165 
    ISSN: 1572-8854
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geologie und Paläontologie , Physik
    Notizen: Abstract The 6-methylsulfonate (I) and the 6-carboxylic acid (II) of 2,4-bis(trichloromethyl)-1,3-benzdioxin both crystallize in the space groupP21/n withZ=4. Unit cell parameters of I are:a=13.398(7),b=14.553(2),c=8.945(2) Å, β=99.16(2)°; those of II are:a=6.010(16),b=25.741(16),c=10.505(10) Å, β=100.05(16)°. The structures were solved by direct methods and refined by full-matrix least squares, from room-temperature data obtained with an Enraf-Nonius CAD4 diffractometer, to conventionalR factors of 0.035 for I and 0.041 for II. The methylsulfonate group of I is disordered except for the sulfur atom and in II, which forms hydrogen-bonded dimers through the −COOH group, the hydrogen atom of the −COOH group is distributed equally between two positions. The conformation and molecular parameters of the 2,4-bis(trichioromethyl)-1,3-benzdioxin fragment for both compounds is very similar to that in 6-nitro-2,4-bis(trichloromethyl)-1,3-benzdioxin (Irving A., and Irving H. M. N. H. (1986)J. Cryst. Spectrosc. Res. 16, 703). The dioxin ring has an approximate envelope conformation with a pseudoequatorial −CCl3 group in the 2-position and a pseudoaxial −CC13 group in the 4-position. C(ring)-Ceq(Cl3) is 1.525(5) Å for I and 1.536(6) Å for II, whereas the C(ring)-Cax(Cl3) bond length is 1.547(5) Å for I and 1.550(4) Å for II. The chemical shifts of the two protons in the heterocyclic ring do not appear to be altered by these changes in the 6-substituent.
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    Journal of chemical crystallography 17 (1987), S. 177-185 
    ISSN: 1572-8854
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geologie und Paläontologie , Physik
    Notizen: Abstract The structure of the title compound, C12H24O6·C6H4OCl2·H2O, has been determined by X-ray diffraction methods. The crystals are monoclinic, space groupP21 witha=8.628(2),b=13.767(4),c=9.676(2), β=96.38(2)°, andD x =1.295 Mg m−3 forZ=2; 2355 reflections were recorded on a CAD4 diffractometer using CuKα radiation atT=243° K. The structure was solved usingMultan andShelx. The finalR value based on 1901 reflections is 0.071. The 18-crown-6 molecule has approximatelyD 3d symmetry. The host molecule (18-crown-6), the guest molecule (dichlorophenol), and water form a super-molecule. Binding between host and guest is effected by bridging water molecule: the water and dichlorophenol molecule are linked by a very strong hydrogen bond (O⋯O=2.58 Å); weaker interactions exist between water and oxygens of the crown ether (O⋯O distances 2.85 and 2.90 Å).
    Materialart: Digitale Medien
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  • 84
    ISSN: 1572-8854
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geologie und Paläontologie , Physik
    Notizen: Abstract The crystal structure of the molecular complex of the antiseptic 9-aminoacridme and the sulfa drug sulfamethoxypyridazine (1∶1), C13H10N2·C11H12N4O3S, has been determined by X-ray diffraction methods. The crystals are orthorhombic: Pbca (No. 61),a=16.321(1),b=16.951(1),c=16.331(1) Å,Z=8,F(000)=1984, andV c =4518.1(5) Å3. The structural parameters have been refined to a finalR value of 0.046 for 3134 observed reflections. The results of X-ray analysis show that the structure contains an acridinium-sulfanilamidate ion pair. A hydrogen atom is transferred from the sulfonamide nitrogen atom to the nitrogen atom of the acridine ring, and an N(acridinium)-H⋯N(sulfonamide) hydrogen bond is formed. A slight folding of the acridine moiety is observed.
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  • 85
    Digitale Medien
    Digitale Medien
    Springer
    Journal of chemical crystallography 17 (1987), S. 207-219 
    ISSN: 1572-8854
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geologie und Paläontologie , Physik
    Notizen: Abstract The title compound, IBA-PIC, is 2C12H13NO2·2C6H3N3O7, triclinic,P¯1,a=7.137(1),b=15.355(4),c=18.282(5) Å,α=79.72(2),β=79.85(2), γ=76.87(2)°. The structure was solved by direct methods and refined by least-squares techniques to anR factor of 0.068 for 3395 observed reflections. The IBA-PIC complex occurs as two independent molecules with different conformations. The crystallographic evidence for a prominent overlapping between the phenyl and indole rings corroborates earlier conclusions from UV spectroscopy. Molecules of both IBA and picric acid lie approximately parallel to (100) in layers and π-bonding interactions across the 3.55 Å spacing. The angles between the indole ring and carboxyl-group planes are 82.9 and 86.9° for the A and B molecules, respectively.
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  • 86
    Digitale Medien
    Digitale Medien
    Springer
    Journal of chemical crystallography 17 (1987), S. 231-249 
    ISSN: 1572-8854
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geologie und Paläontologie , Physik
    Notizen: Abstract The crystal and molecular structure of ursodeoxycholic acid (3α,7β-dihydroxy-5β-cholanoic acid),] C24H40O4, is reported. Crystals are orthorhombic, space groupP212121 (No. 19) withZ=8 in a cell of dimensions,a=12.311(1),b=13.272(1), andc=26.615(2) Å. The structure has been refined to a residual of 0.056 for 4153 significant reflections measured on a four-circle diffractometer using copper radiation. The twe molecules in the asymmetric unit have conformations typical of other bile acids with ringsA andB beingcis-fused. The hydroxyl group of C7 isβ-equatorial in each molecule, but the 17β side chains adopt different conformations in the two molecules. In the crystal structure a complex hydrogen bonding network involves both hydroxyl and carboxyl groups. The crystal structure is compared to that of chenodeoxycholic acid, (3α,7α-dihydroxy-5β-cholanoic acid.
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  • 87
    Digitale Medien
    Digitale Medien
    Springer
    Journal of chemical crystallography 17 (1987), S. 259-265 
    ISSN: 1572-8854
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geologie und Paläontologie , Physik
    Materialart: Digitale Medien
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  • 88
    ISSN: 1572-8854
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geologie und Paläontologie , Physik
    Notizen: Abstract A pink-red air-stable, crystalline compound of empirical formula [Cu(Im)4(N-tsval)2] (Im=imidazole; ts=4-toluenesulfonyl group, hereafter abbreviated as tosyl;N-tsval=N-tosylvalinate monoanion) was synthesized and characterized by means of structural and spectroscopic measurements. The crystal structure of the compound was determined from three-dimensional diffractometer data. The crystals are monoclinic, space groupC2/c, a=18.952 (5),b=12.372 (2),c=17.594 (3) Å,β=93.77 (2)°,Z=4. The structure was solved by the heavy-atom method and refined through least-squares calculations toR=0.035 for 2284 observed reflections. The coordination about the copper atom is elongated octahedral, with four imidazole molecules as equatorial ligands and two sulfonic oxygens in axial positions.
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  • 89
    Digitale Medien
    Digitale Medien
    Springer
    Journal of chemical crystallography 17 (1987), S. 411-413 
    ISSN: 1572-8854
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geologie und Paläontologie , Physik
    Materialart: Digitale Medien
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  • 90
    ISSN: 1572-8854
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geologie und Paläontologie , Physik
    Notizen: Abstract A qualitative, but detailed, account of the phenomenon of L.O.-T.O. splitting in the Raman spectroscopy of noncentrosymmetric crystals is given. Tables are provided which give predictions for 45°, 90°, and 180° scattering geometries for all such crystals.
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  • 91
    ISSN: 1572-8854
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geologie und Paläontologie , Physik
    Notizen: Abstract The crystal and molecular structure of the title compound, obtained by intramolecularN,S-dialkylation of 5,5-diphenyl-2-thiohydantoin with ethyl-2,3-di-bromopropionate, has been determined from X-ray diffractometer data. Ethyl-2-{2,3-dihydro-6,6-diphenylimidazo-[2,1-b]-thiazol-5(6H)-one}formate crystallizes in space groupP21/c witha=12.166(4),b=10.689(2),c=15.021(6) Å,β=113.63(4)°, andZ=4. The molecular structure was found with nonplanar thiazole ring. The structure was solved withR=0.051.
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  • 92
    Digitale Medien
    Digitale Medien
    Springer
    Journal of chemical crystallography 17 (1987), S. 505-514 
    ISSN: 1572-8854
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geologie und Paläontologie , Physik
    Notizen: Abstract 6,8-Dinitro-2-trichloromethyl-4-dichloromethylene-1,3-benzdioxin is orthorhombic,Pccn,a=18.850(3),b=18.404(3),c=8.849(2) Å,Z=8. The structure was solved by direct methods, from data collected at room temperature on an Enraf-Nonius CAD4 diffractometer, and refined by least squares to a finalR value of 0.036 using 1889 reflections. The heterocyclic ring has an envelope conformation and is substituted pseudo-equatorially by a trichloromethyl group. The molecular parameters and conformation of the title compound are discussed with reference to the 6-nitro analog and with reference to 6-nitro and 6,8-dinitro-2, 4-bis(trichloromethyl)-1,3-benzdioxin.
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  • 93
    ISSN: 1572-8854
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geologie und Paläontologie , Physik
    Notizen: Abstract The title compound was prepared during the course of an attempt to synthesize 8-amino-3-benzyl-6-methylimidazo[4,5-e][1,2,4]triazepine. The crystals are monoclinic, space groupP21/c,a=6.2375(5),b=9.1070(8),c=22.182(2) Å,β=91.797(7)°,Z=4. The structure was solved by direct methods and refined by least squares toR=0.063 on all 2142 measured reflections. The imidazol-4-yl-triazole system is planar, conjugated, and aromatic. One hydrogen atom of the exocyclic amino group is involved in a bifurcated hydrogen bond, of which one branch is an intramolecular attraction to a triazole ring nitrogen atom, while the other branch is intermolecular. The crystal is held together by two N-H⋯N hydrogen bonds between molecules related by translation along thea axis and byπ-π stacking interactions of the imidazol-4-yl-triazole ring systems and the phenyl rings across centers of inversion.
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  • 94
    ISSN: 1572-8854
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geologie und Paläontologie , Physik
    Notizen: Abstract The crystal structure of 2-(carboxy-3′-propyl)-3-amino-6-cyclohexylpyridazinium bromide has been determined by single-crystal X-ray diffraction techniques and refined by full-matrix least squares. The compound crystallized in the tri-clinic space groupP ¯1 witha=10.275(1),b=11.215(1),c=7.082(1) Å,α=91.84(1),β=102.21(1), γ=106.77(1)°, andZ=2. FinalR-factor is 0.045. The main structural results are very similar to the ones observed for the 6-phenyl analog. These two compounds are GABA-A antagonists.Ab initio molecular orbital calculations, with STO-3G and 4-31G basis sets, suggest that the exocyclic nitrogen accurately mimics the nitrogen atom of GABA.
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  • 95
    Digitale Medien
    Digitale Medien
    Springer
    Journal of chemical crystallography 17 (1987), S. 585-595 
    ISSN: 1572-8854
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geologie und Paläontologie , Physik
    Notizen: Abstract The title compound, (C6H10N3O2)ClO4, has been prepared and its crystal structure has been determined by X-ray analysis. The crystal of the L-histidinium perchlorate is monoclinic, the space group isP21,Z=2 witha=5.052(1),b=9.194(2),c=10.388(2) Å,β=92.34(1)°,V=482.1(3)Å3, F(000)=264,D x =1.761 andD 0=1.769(1) Mg m−3. The conformation of the histidinium cation is fully extended, with the imidazole grouptrans to the carboxyl group across the C α -C β bond. There is an extensive array of hydrogen bonds formed in the crystal. The cations are connected between them and to the perchlorate anions through hydrogen bonds. These hydrogen bonds plus electrostatic interactions account for the adopted molecular conformation. The spectroscopic study shows that the cations are protonated and the anion presents the well-known infrared spectrum for perchlorates.
    Materialart: Digitale Medien
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  • 96
    ISSN: 1572-8854
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geologie und Paläontologie , Physik
    Notizen: Abstract C12H14CuF2N2O3,M=335.797, monoclinic, space groupP21/n,a=6.985(2),b=17.406(2),c=10.581(2) Å,β=92.41(2)°,V=1285(1) Å3,D c =1.736 g cm−3,Z=4,F(000)=684,μ(CuKα)=27.0 cm−1, λ=1.5418 Å,T=20°C, crystal dimensions=0.75×0.45×0.30 mm. The structure of the title compound shows it to be [Cu(phen)F2(H2O)]·2H2O with pentacoordinate-square pyramidal Cu(II), short Cu-F bonds [1.890(4) and 1.891(4) Å], and short F⋯H-O hydrogen bonds (ca. 2.68 Å) between the complex and lattice water molecule.
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  • 97
    Digitale Medien
    Digitale Medien
    Springer
    Journal of chemical crystallography 17 (1987), S. 653-659 
    ISSN: 1572-8854
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geologie und Paläontologie , Physik
    Notizen: Abstract For the first time, a transannular II-cyclization and subsequent transannularO-heterocyclization is obtained during an electrophilic addition to a large-ring triene. The structure of the product—anti,exo,exo-5,10,12-tribromo-13-oxa-exo-tricyclo[7.3.1.02,6]tridecane—was determined by X-ray analysis.
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  • 98
    Digitale Medien
    Digitale Medien
    Springer
    Journal of chemical crystallography 17 (1987), S. 661-670 
    ISSN: 1572-8854
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geologie und Paläontologie , Physik
    Materialart: Digitale Medien
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  • 99
    Digitale Medien
    Digitale Medien
    Springer
    Journal of chemical crystallography 17 (1987), S. 675-682 
    ISSN: 1572-8854
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geologie und Paläontologie , Physik
    Notizen: Abstract The higher-melting (mp 236°C)α-isomer of “dithioparachloral,” i.e.,α-2,4,6-tris(trichloromethyl)-1-oxa-3,5-dithian, is orthorhombic,Pnma,a=9.983(2),b=15.318(2),c=10.416(2) Å,V=1592.81 Å3,Z=4. The structure was solved by direct methods, from data collected at room temperature on an Enraf-Nonius CAD4 diffractometer, and refined by least-squares to a finalR value of 0.040 using 1017 reflections. The molecule is in the chair conformation with all threecis-CCl3 groups located pseudoequatorially. Endocyclic parameters are: torsion angles (deg) C-O-C-S 75.1(3), O-C-S-C −63.2(3), C-S-C-S 62.4(3); angles (deg) C-O-C 111.9(2), O-C-S 112.6(3), C-S-C 94.8(2), S-C-S 113.2(1); bond lengths (Å) O-C 1.426(5), C-S 1.824(4), S-C 1.818(3) (quoted in cyclic order).
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  • 100
    Digitale Medien
    Digitale Medien
    Springer
    Journal of chemical crystallography 17 (1987), S. 701-711 
    ISSN: 1572-8854
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geologie und Paläontologie , Physik
    Notizen: Abstract The title compound (C20 H 12Cl2,M r =322, mp 69–70°C) crystallizes in the monoclinic system, space groupP21/n, witha=3.942(2),b=6.887(2),c=28.701(4) Å,β=91.362(4)°,V c =778.93(2) Å3,Z=2,D c =1.373,D m =1.370(1) (in C6H6/CCl4) g cm−3,F(000)=332 and μ(MoKα)=3.57 cm−1. The final residuals areR=0.0365 andR w =0.0368 for 999 observed reflections at the levelI≥3σ(I). The molecule as a whole is found to havetrans conformation. This structural study reveals that the title compound does not undergo solid-state polymerization due to close packing.
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