ALBERT

Notizen: This paper takes seriously the idea that international trade has played an important role in explaining both some convergence between developed economies as well as rising inequalities at the personal level. Previous studies used traditional trade theory as a reference framework. The empirical consensus is now that differences in factor endowment explain at best a small fraction of rising wage inequalities. This argument, by contrast, builds on labor specialization and increasing returns. Deeper economic integration allows trade in differentiated intermediate goods and primary tasks, thus transforming local increasing returns into global increasing returns. This pushes towards geographical equalization. At the same time, deeper integration also increases the size of the pool of available skilled workers. This may lead them to a‘technological secession’as it makes more skill-demanding technologies more profitable. Technological secession in turn fosters wage inequalities at the personal level.

Notizen: The effects of state public capital investment on economic growth is an important question that has been the focus of a recent substantial research effort. But the majority of this research has ignored these investments’influence on the intra-state pattern of economic activity. Yet if external agglomeration economies are important determinants of growth, then investments may indirectly affect growth by fostering or discouraging agglomeration. This paper discusses the effect of state infrastructure investments on the distribution of employment within states and the implications of these spatial effects for aggregate state employment growth. Preliminary empirical results suggest that state infrastructure investments tend to redistribute growth from areas of dense employment to other parts of the state. This redistribution may diminish agglomeration benefits offered by cities, which has the potential to reduce state growth. The paper concludes with a discussion of implications of the work for research and policy.

Notizen: This article examines diverse transnational corporations’(TNC) strategies in response to labor shock and specific conditions that enhance TNCs’local embedding in export processing zones (EPZs). The goal of this paper is to understand the rationale behind TNCs’choice between spatial differentiation (mobility) and spatial fmity (immobility). Based on field research and data analysis from the Masan Free Export Zone (MAFEZ) in South Korea, it is argued that TNCs do not always withdraw from EPZs in reaction to wage costs and growing labor militancy. Higher labor costs can be overridden by other advantages: existing physicalkocial inhstructure, tax benefits, fured assets, localized labor skills and technology, cultural proximity, and advantages from geographical proximity to market, raw materials, and TNCs’headquarters. This paper criticizes the overly simplistic view of capital mobility. However, TNCs that choose to remain in the EPZs use both upgrading and cheapening strategies, and their remaining does not necessarily result in upgrading labor skills or improving labor conditions. This article raises a critical question of the firm-centered view of the global enterprise literature and the local embeddedness literature of TNCs on workers’welfare. It emphasizes the important role of firms and of unions in training workers for purposes of technology and skill upgrading.

Notizen: Overall total inequality for state per capita personal income as well as total inequality for nonmetropolitan and metropolitan areas are examined for the period 1969 to 1995. In each case, the total inequality was partitioned into between-and within-region variations. Statistical testing shows no perceptible differences between the major categories, nonmetropolitan and metropolitan. Further, this study uses a model to test for narrowing of income gaps within these categories. It was found that for both nonmetropolitan and metropolitan, a general trend toward equality was evidenced during the early 1970s decade. In that decade, the nonmetropolitan areas’incomes approached the metropolitan areas’incomes but showed significant divergences in the 1980s, followed again by a narrowing of the gaps in the 1990s.

Notizen: Foreign exports are claiming growing shares of US. state economic production. While growth of foreign exports is often cited as a driving force for state economic growth, little attention has been paid in prior research to the issue of Granger causality between foreign exports and economic performance at the state level. This study examines Granger causality between foreign manufacturing export growth and state manufacturing performance during the period from 1980 to 1991. Results indicate that, at the aggregate level, there is a bi-directional Granger causal relationship between foreign exports and state manufacturing activity. Among the individual industrial sectors, results are more mixed, however, with sectors displaying either export-led growth, reverse Granger causality, or in some instances, negative Granger causality.

Notizen: A modification of the Boamet model of local economic change is developed that links the growth of urban nodes in functional economic regions to employment and population change in the rural hinterlands of these regions. The two-equation model uses labor market and residential zone observations that are consistent with commuter fields around each rural community in the regions studied. The model parameters are estimated for 204 Danish rural municipalities, for 3515 rural communes in six regions of Eastern France, and for 268 rural census tracts in South Carolina. Results indicate that urban nodal spread effects are often significant and tend to dominate urban backwash impacts on rural communities. Accordingly, rural communities need to be concerned with the economic fortunes of their urban nodes and with policies that affect the pattern of urban growth between urban center and the urban fringe.

Notizen: Several empirical studies have estimated the value of agricultural land as open space to local residents. An important goup of individuals that may be affected by the loss of agricultural land are visitors to a region. The value of ranchland to tourists visiting a resort town in the Rocky Mountains is estimated through a travel cost model that combines information on observed behavior data from actual trips with contingent behavior data on intended current visitation if the resource were converted to urban and resort uses. The value of ranch open space to tourists is the gain or loss in consumer surplus derived from a visit to the study area attributable to the resource. A random effects Poisson regression model is estimated because of the panel nature of the data, accounting for the correlation of the multiple responses from heterogeneous individuals. Twenty-five percent of the sample would reduce visitation and 23 percent of the sample would increase visitation if ranch open space were converted to urban and resort uses. The overall effect of converting ranch open space to resort and urban uses is no net change in average consumer surplus per trip for summer tourists in general.

Notizen: The welfare effects of public versus private waste disposal with and without flow controls are analyzed. The pricing of private waste disposal services is modeled as being bounded above by the public entity's average disposal cost, but constrained by potential entry of private competitors. It is found that once a publicly owned disposal facility has been built, waste generators are almost always better off if their local government has flow control authority. This results from the necessity of covering the fixed costs of the public facility once it has been built, in conjunction with the expected pricing behavior of private firms.

Notizen: Interest in the use of adjustment models has recently increased as analysts have come to see the value of these models in the study of regional growth processes. Adjustment models are especially useful in clarifying the nature and direction of population-employment interactions. However, other models of regional growth suggest that employment should not be treated as a single homogeneous variable, as is the usual assumption in regional adjustment models. This paper looks at the issue of employment disaggregation, and suggests that adjustment models can be alternatively specified by making use of economic base theory to separate employment into at least two broad sectors. Alternative economic base specifications are tested using data for the nonmetropolitan counties (n=254) of the US. Rocky Mountain West during a recent time period. The results show that an economic base version of the adjustment model provides insights to regional change that are not available from the traditional version of the model.

Notizen: Book review in this article:East Asian Development: Will the East Asian Growth Miracle Survive? Edited by F. Gerald Adams and Shinichi Ichimura.Regional Change in Industrializing Asia. Edited by Leo van Grunsven.Black Powe/White Power in Public Education, by Ralph Edwards and Charles V. Willie.

Notizen: Fiscal devolution fiom federal to state jurisdictions gives states more authority but also more responsibility for redistributing and stabilizing income. Both the revenue and expenditure sides of a state's budget are affected. This paper describes a social accounting matrix approach to documenting multi-regional, multi-jurisdiction fiscal accounts, called a fiscal SAM. Two of the many potential uses of a fiscal SAM are demonstrated. First, a fiscal SAM of rural, urban, and metro areas of Iowa is used directly to describe and compare the benchmark net fiscal situations of interdependent regions. Second, it is used to analyze the impacts of an economic downturn under a block-grant welfare system.Substate regions are relatively more specialized than state or national economies. Thus, for example, shocks to agriculture will directly affect agriculture-dependent counties more than other types of counties. Substate regions are also more interdependent than states, as well as more open than the nation as a whole. This means that indirect and spatial spillover effects of fiscal and other exogenous changes can be surprisingly large between counties. Here, analysis of fhe multipliers highlights the relative intensities of within and across-region effects of changes in the form of intergovernmental transfers. The multiplier simulation estimates the relative impacts and spillover effects of economic shocks under the new regime.

Notizen: Many counties in the mountainous areas of the western U.S. are experiencing rapid growth in population and income, even though extractive industries that served historically as their primary economic base are in decline. The purpose of this paper is to establish statistically the spatial determinants of population, employment, and income densities in 86 rural mountain counties and any changes in those determinants between 1985 and 1994. The results of this analysis indicate that densities are oriented to regional metropolitan centers and critical amenities such as ski areas, national parks, and universities or colleges. Negatively sloped density gradients with respect to distance from regional metropolitan centers suggest that the densities of settlement patterns beyond metropolitan boundaries are analogous to those within metropolitan areas relative to urban centers. In short, a tension apparently exists in locational choice; residents of the Mountain West desire to live near the beauties and amenities of the mountain landscape but do not want to entirely sever their urban ties. Because amenities are the primary attraction of mountain counties rather than employment in locationally dependent industries, at least some migrants must have relatively footloose forms of income.

Notizen: Book review in this article:The California Cauldron: Immigration and the Changing Fortunes of Local. Communities. By William A.V. Clark.Structural Economics, by Faye Dunchin.

Notizen: This paper examines the competitive characteristics of small and medium-sized manufacturing firms (SMFs) in a Canada-U.S. crossborder region (the Niagara Frontier). Particular attention is given to the innovation and business performance of comparably-sized firms on both sides of the border. The results of two firm-level surveys are presented. A comparative analysis of the two groups suggests that Canadian Sh4Fs exhibit significantly stronger export and innovation performance than their US. counterparts. The results also suggest that U.S. firms face tougher competitive difficulties arising fiom specific national and regional circumstances, including shortages of skilled labor, higher corporate tax rates, rising import competition, and a more complex regulatory environment. The implications of the empirical results are discussed in the context of policy options for regional economic development in crossborder zones such as the Niagara Frontier

Notizen: The design and improvement of products and processes often calls for experiments where several response variables are analyzed simultaneously. Frequently, some of these variables are sensory attributes that can only be measured subjectively, through sensory evaluation panels or using expert opinion. In this paper we apply a multiresponse optimization procedure presented in Fogliatto and Albin 1997, to optimize a military food product where 24 sensory attributes are evaluated through descriptive analysis techniques. Our objective is to select the best design and operating control factors considering all attributes simultaneously.

Notizen: In a double-blind crossover study, 94 symptomatic adult patients with allergic rhinitis rated sensory preferences for single exposures (2 sprays in each nostril) to three intranasal corticosteroids: triamcinolone acetonide AQ, beclomethasone dipropionate AQ, and fluticasone propionate. Each patient was given the medication and then immediately asked to use a 100-point scale to rate 13 attributes: comfort to take the medicine, medicine run-off, irritation, strength of urge to sneeze, strength of odor, liking odor, strength of taste, strength of bitter taste, liking taste, and moistness of nose and throat, and then (at least 2 min after administration) irritation, medicine run-off, and overall liking. The order of drug presentation was randomized across patients and a 30-min rest interval occurred between drug administrations. Triamcinolone was lower in odor strength than both beclomethasone and fluticasone (mean scores of 8 vs 57 and 52, respectively; P〈0.001) and the odor of triamcinolone was preferred to the odor of the two other sprays (mean score of 72 vs 55 and 55, respectively; P〈0.001). While the taste intensity ratings of the three sprays were not significantly different, the triamcinolone taste was liked more than that of fluticasone (mean scores of 55 vs 41, P〈0.04). Overall, triamcinolone was liked more than fluticasone (P〈0.05). In summary, patient preference testing has shown that triamcinolone is preferred over beclomethasone and/or fluticasone in terms of odor and taste. Such preferences may be important in treatment compliance and outcomes.

Notizen: Milk powders available commercially are of different qualities. The quality deviations may be due to inherent quality of the milk which in turn is dependent on various conditions like the fat content, the processing parameters, the storage time and the packaging materials used. The various brands of milk powders have been profiled sensorily for odor and flavor and also positioned using Canonical Discriminant Analysis (CDA). The study throws light on the relative qualities of the different brands, their positive and negative points and their relative position with respect to each other. The results indicate that the various types like whole milk powder, partially skimmed milk powder, skimmed milk powder and infant milk formula cluster together into the same group but the groups are separate from each other. The dominant quality attributes for the groups are different and are discussed in relation to the directional vectors.

Notizen: Differences in sensory acuity and hedonic reactions to products lead to latent groups in pooled ratings data. Manufacturing locations and time differences also are sources of rating heterogeneity. Intensity and hedonic ratings are ordered categorical data. Categorical responses follow a multinomial distribution and this distribution can be applied to pooled data over trials if the multinomial probabilities are constant from trial to trial. The common test statistic used for comparing vectors of proportions or frequencies is the Pearson chi-square statistic. When ratings data are obtained from repeated ratings experiments or from a cluster sampling procedure, the covariance matrix for the vector of category proportions can differ dramatically from the one assumed for the multinomial model because of inter-trial. This effect is referred to as overdispersion. The standard multinomial model does not fit overdispersed multinomial data. The practical implication of this is that an inflated Type I error can result in a seriously erroneous conclusion. Another implication is that overdispersion is a measurable quantity that may be of interest because it can be used to signal the presence of latent segments. The Dirichlet-Multinomial (DM) model is introduced in this paper to fit overdispersed intensity and hedonic ratings data. Methods for estimating the parameters of the DM model and the test statistics based on them to test against a specified vector or compare vectors of proportions are given. A novel theoretical contribution of this paper is a method for calculating the power of the tests. This method is useful both in evaluating the tests and determining sample size and the number of trials. A test for goodness of fit of the multinomial model against the DM model is also given. The DM model can be extended further to the Generalized Dirichlet-Multinomial (GDM) model, in which multiple sources of variation are considered. The GDM model and its applications are discussed in this paper. Applications of the DM and GDM models in sensory and consumer research are illustrated using numerical examples.

Notizen: A sensory panel utilized chicken patties from Pectoralis major muscle to develop a descriptive vocabulary for warmed-over flavor. Patties were subjected to 4 different cooking temperatures and stored at 4C for up to 4 days. A list of 33 descriptive terms, developed from the literature and a preliminary sample evaluation was modified over 5 daily sessions to 18 terms with corresponding references. In the term selection process the criteria used were, that terms should; have relevance to the product, discriminate clearly between samples, be nonredundant, and have cognitive clarity to the assessors. A comprehensive vocabulary was developed that described the sensory dimensions present in the samples. Over sessions the panel was found to display dynamic changes in their use of the sensory vocabulary. Overall, panel discriminative abilities were enhanced and a process of sensory learning was observed.

Notizen: The regional atmospheric climate model HIRHAM has been applied to the Arctic. Simulations for the whole year 1990 and for an ensemble of winter months (January of 1985-1995) have been performed. The comparison of the simulations with observational data analyses shows that the general spatial patterns are in good agreement with the data, in both the vertical structure and the annual cycle. For an additional validation of the model results, a multivariate classification of large-scale circulation patterns has been applied to the January ensemble model simulations.

Notizen: We investigate the response of the Nordic seas-Arctic Ocean system to surface freshwater flux anomalies that we regard as typical for long-term atmospheric variability. We employ response experiments with a coupled sea ice-ocean model where we introduce a surface freshwater flux anomaly (A) over the Norwegian Sea and (B) in the Laptev Sea. Case A offers an explanation for the intermediate depth salinity changes observed in the Amundsen Basin. The signal observed there belongs to an original perturbation that, according to the model, occurred around a decade earlier. Salinity fluctuations in the Laptev Sea could play a role in changes in the near surface salinity in the Amundsen Basin.

Notizen: Observation of the retreat and disintegration of ice shelves around the Antarctic Peninsula during the last three decades and associated changes in air temperature, measured at various meteorological stations on the Antarctic Peninsula, are reviewed. The climatically induced retreat of the northern Larsen Ice Shelf on the east coast and of the Wordie, George VI, and Wilkins ice shelves on the west coast amounted to about 10 000 km2 since the mid-1960s. A summary is presented on the recession history of the Larsen Ice Shelf and on the collapse of those sections north of Robertson Island in early 1995. The area changes were derived from images of various satellites, dating back to a late 1963 image from the recently declassified US Argon space missions. This photograph reveals a previously unknown, minor advance of the northern Larsen Ice Shelf before 1975. During the period of retreat a consistent and pronounced warming trend was observed at the stations on both east and west coasts of the Antarctic Peninsula, but a major cause of the fast retreat and final collapse of the northernmost sections of the Larsen Ice Shelf were several unusually warm summers. Temperature records from the nearby station Marambio show that a positive mean summer temperature was reached for the first time in 1992-93. Recent observations indicate that the process of ice shelf disintegration is proceeding further south on both sides of the Antarctic Peninsula.

Notizen: To determine the factors restricting plant reproduction in front of a glacier, the gender expression and seed production of Dryas octopetala L. (Rosaceae) were observed, as well as the grazing pattern of reindeer on flowers, near Brøggerbreen (Brøgger Glacier), which is near Ny-Ålesund (78° 55'N, 11° 56'E), Svalbard. Three hundred shoots with flowers and flower buds were randomly tagged in early July 1996. Between then and the end of flowering in late July, 100 (33%) flowers and buds were grazed by reindeer. Out of the surviving flowers, 145 (76%) shoots had hermaphrodite flowers, while 45 (24%) shoots had male flowers without a developed gynocium. Male flowers, which appeared later than hermaphrodite flowers in the population, were significantly smaller than hermaphrodite flowers in dry weight. In the hermaphrodite flowers, moreover, smaller flowers showed lower dry-weight allocation to the gynoecium as compared to larger flowers. During the observation, hermaphrodite flowers did not produce any developed seeds under a natural condition (0% seed-set). Cross-pollinated flowers showed 8% seed-set. On the other hand, flowers which were artificially warmed in small greenhouses during the flowering period showed 60% seed-set, regardless of cross-pollination or autodeposition of pollen from anthers to stigma (self-pollination). Thus, it was found that grazing, gender variation in relation to the length of the growing season and the flower size, and - in the floweriing period - low temperature rather than pollinator limitation strongly affected the seed production of D. octopetala in the population studied.

Notizen: In the near coastal regions of Dronning Maud Land, Antarctica, below-surface ice-melt in blue-ice areas has been observed. The low scattering coefficients of the large-grained blue-ice allow penetration of solar radiation, thus providing an energy source below the ice surface. The sub-surface meltwater is significant enough to show up on remote-sensing imagery in the form of ice-covered lakes. Adjacent snow-accumulation areas have much higher scattering coefficients and consequently limit solar radiation penetration in these regions. These snow and ice surfaces are generally below freezing, and little surface melting occurs. To assess the response of these melt features to changes in atmospheric forcings such as cloudiness, air temperature, and snow accumulation, a physically-based model of the coupled atmosphere, radiation, snow, and blue-ice system has been developed. The model consists of a heat transfer equation with a spectrally-dependent solar-radiation source term. The penetration of radiation into the snow and blue-ice depends on the surface albedo, and the snow and blue-ice grain size and density. Model simulations show that ice melt occurring in this area is sensitive to potential variations in atmospheric forcing. Under certain conditions more traditional surface melting occurs and, under other conditions, the existing melt processes can be shut down completely. In light of the sensitivity of this system to variations in atmospheric forcing, and the ability to view melt-related features using remote sensing, a tool exists to efficiently monitor variations in Antarctic coastal climate.

Notizen: The Holocene glacial and climatic development in Antarctica differed considerably from that in the Northern Hemisphere. Initial deglaciation of inner shelf and adjacent land areas in Antarctica dates back to between 10-8 Kya, when most Northern Hemisphere ice sheets had already disappeared or diminished considerably. The continued deglaciation of currently ice-free land in Antarctica occurred gradually between ca. 8-5 Kya. A large southern portion of the marine-based Ross Ice Sheet disintegrated during this late deglaciation phase. Some currently ice-free areas were deglaciated as late as 3 Kya. Between 8-5 Kya, global glacio-eustatically driven sea level rose by 10-17m, with 4-8 m of this increase occurring after 7 Kya. Since the Northern Hemisphere ice sheets had practically disappeared by 8-7 Kya, we suggest that Antarctic deglaciation caused a considerable part of the global sea level rise between 8-7 Kya, and most of it between 7-5 Kya. The global mid-Holocene sea level high stand, broadly dated to between 8-4 Kya, and the Littorina-Tapes transgressions in Scandinavia and simultaneous transgressions recorded from sites e.g. in Svalbard and Greenland, dated to 7-5 Kya, probably reflect input of meltwater from the Antarctic deglaciation.

Notizen: UV-B tolerance and susceptibility of high Arctic morphotypes of the Daphnia pulexl D. tenebrosa complex were assessed by in situ experiments at Ny-Ålesund, Svalbard (79°N). Animals from local ponds were exposed to ambient light plus additional UV-B from lamps in a greenhouse facility. Taxonomic affinities did not appear as major determinants of UV susceptibility, but a major difference in UV-B tolerance was seen between morphotypes with pigmented carapaces and those without, the latter being far more susceptible. Assays on levels of carotene and the anti-oxidant enzymes catalase and superoxide dismutase did not reveal clear-cut differences between populations, and could not account for the higher tolerance in pigmented populations. Levels of glutathione transferase were higher in the transparent population, however. In the absence of blue light and UV, laboratory reared animals did not reconstitute their carapace melanization after moulting, indicating that short-wave light is the cue for melanin synthesis. Tests on melanized individuals and individuals of the same population reared indoors through 1-2 moults supported the major role of melanin for UV protection. Periods with high UV exposure during hatching of ephippia could induce shifts in morphotype or clonal dominance.

Notizen: During the 17th and 18th centuries, tens of thousands of Greenland right whales were killed as a result of extensive European whaling in the coastal waters of the Svalbard archipelago. The author reconstructed these whaling activities, examined how the changing climate affected whaling productivity, and considered the consequences of climate and whaling on the species and on the North Atlantic ecosystem. Annual catch records made it possible to calculate the original size of the whale population; its natural migration pattern in the Greenland Sea could be reconstructed using shipping logs and itineraries. Other written sources revealed that besides human hunting activities, climate change played an important role in the elimination of the Greenland right whale from the Arctic marine ecosystem. This elimination made millions of plankton available for other marine mammals, polar cod and planktonfeeding birds. This has caused a major shift in the food web. changing the marine ecosystem in Svalbard.

Notizen: Responses to global change impacts require the specification of mitigation and adaptation options. Integrated regional impact studies provide some of the information needed for rational decision making. In order to carry out a comprehensive impact study, the involvement of stakeholders in the planning and execution of the study is seen as a necessary prerequisite for an acceptance of its conclusions by the broad public. One way to pursue such an involvement is through a scientist-stakeholder collaborative. Such a collaborative, for instance institutionalized through a joint scientist-stakeholder steering committee addressing issues related to mutual communication and the integration of individual study results, offers a number of additional advantages. The experience of local residents and the utilization of traditional knowledge may provide insight and expertise inaccessible to scientific investigations. Within the Barents Sea Impact Study, the involvement of stakeholders has been given significant weight early on. One of the main instruments employed in the stakeholder collaborative is the BASIS Information Office. However, given the diversity of backgrounds and interests of stakeholders from four different countries, scientist-stakeholder collaboration represents a significant challenge within BASIS. This notwithstanding, we consider the advantages gained worth the extra effort.

Notizen: The nutrient status of soils surrounding ten snow petrel Pagodroma nivea nests was investigated by sampling along four transects (One up-slope and three down-slope) from each nest. The highest levels for total N and P.% C. nitrite and ammonia (but not nitrate) were associated with the nest itself. Elevated levels of all nutrients still occurred at I m from the nest but dropped to levels similar to those of non-bird influenced soils at 2 m or 5 m from the nest. Highest bacterial and algal numbers were also associated with the nest. An experiment to examine the breakdown of guano showed nitrification levels to be insignificant and nutrient release levels very slow.

Notizen: Concetrations of 16 elements (Al, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Zn, C, N, S, P, Ca, Mg) were determined in the lichen Cladina stellaris (Opiz) Brodo collected from 26 localities on the Kola Peninsula. Concentrations were higher closer to the emission sources. In Arctic regions affected by local emissions. lichens can be recommended as sensitive indicators of atmospheric pollution.

Notizen: : Existing legal regimes for the management of water resources are already stressed by changing technologies and growing populations. There is little reason for doubt that today the planet is undergoing significant and even alarming climate change. In the past such global climatic changes had dramatic effects on water resource availability with disastrous consequences for many human communities. Today's climate changes can be managed without such disastrous consequences for present day communities only if there are major reforms to existing water law regimes at the local, national, and international levels. In particular, at the local and national levels, water resources must be treated as public property rather than as common or private property. At the international level, water must be managed at the drainage basin level rather than according to national boundaries that largely ignore rational water management criteria. At all levels, care must be given to decentralizing decision making and to use economic incentives insofar as possible, without, however, mistaking economic incentives for markets. The public nature of water resources precludes true markets as a significant management tool.

Notizen: : Understanding the effects of climate change on water resources requires coupling atmospheric and hydrologic models. With the wide array of hydrologic models, from simple empirical to complex physically based, it is not clear which is preferable to simulate hydrologic variations over long time scales. To address this issue, a black-box artificial neural network (ANN) model was compared to a distributed parameter conceptual Geographic Information System based Hydrologic Modeling System (GIS-HMS). Both models computed daily direct surface runoff in four sub-basins of the West Branch of the Susquehanna River Basin, Pennsylvania and were evaluated with five objective functions. Overall, results were comparable between models. However, the ANN was favored in the larger sub-basins, while GIS-HMS was more accurate in the smaller catchments. Both models were impaired by the poor spatial and temporal resolution of precipitation data and the simplified representation of antecedent soil-moisture conditions. In the context of climate change, where simulations are limited by computing power, results suggest that both models are appropriate. When detailed simulations are essential, GIS-HMS is a preferable model to use. On the other hand, the ANN model is more suitable when multiple scenarios require immediate analysis and the distributed qualities of runoff are not required.

Notizen: : We review published analyses of the effects of climate change on goods and services provided by freshwater ecosystems in the United States. Climate-induced changes must be assessed in the context of massive anthropogenic changes in water quantity and quality resulting from altered patterns of land use, water withdrawal, and species invasions; these may dwarf or exacerbate climate-induced changes. Water to meet instream needs is competing with other uses of water, and that competition is likely to be increased by climate change. We review recent predictions of the impacts of climate change on aquatic ecosystems in eight regions of North America. Impacts include warmer temperatures that alter lake mixing regimes and availability of fish habitat; changed magnitude and seasonality of runoff regimes that alter nutrient loading and limit habitat availability at low flow; and loss of prairie pothole wetlands that reduces waterfowl populations. Many of the predicted changes in aquatic ecosystems are a consequence of climatic effects on terrestrial ecosystems; shifts in riparian vegetation and hydrology are particularly critical. We review models that could be used to explore potential effects of climate change on freshwater ecosystems; these include models of instream flow, bioenergetics models, nutrient spiraling models, and models relating riverine food webs to hydrologic regime. We discuss potential ecological risks, benefits, and costs of climate change and identify information needs and model improvements that are required to improve our ability to predict and identify climate change impacts and to evaluate management options.

Notizen: : This research examines the sensitivity and vulnerability of community water systems (CWSs) to weather and climate in the Pennsylvania portion of the Susquehanna River Basin. Three key findings emerge from a survey of 506 CWS managers. First, CWSs are sensitive to extreme weather and climate, but that sensitivity is determined more by type of system than system size. CWSs that rely partly or wholly on surface water face more disruptions than do groundwater systems. Larger systems have more problems with flooding, and size is not a significant determinant of outages from storms or disruptions from droughts. Second, CWS managers are unsure about global warming. Few managers dismiss global warming; most think global warming could be a problem but are unwilling to consider it in their planning activities until greater scientific certainty exists. Third, the nature of the CWS, its sensitivity to weather and climate, and projected risks from weather and climate are insignificant determinants of how managers plan. Experienced, full-time managers are more likely to consider future weather and climate scenarios in their planning, while inexperienced and part-time managers are less likely to do so. Implications of these findings include support for efforts to move away from surface water, for clear communication of climate change information, and for the hiring and retention of full-time professional CWS managers.

Notizen: : To fully take advantage of regional climate forecast information for agricultural applications, the relationship between divisional and station scale precipitation characteristics must be quantified. The spatial variability of monthly precipitation is assumed to consist of two components: a systematic and a random component. The systematic component is defined by differences in long-term mean precipitation between stations within a climate division, and the random component by differences between station and divisional standardized values. For the Central Climate Division of Oklahoma, the systematic component has a positive precipitation gradient from west to east with a slope ranging between 3 to 16 mm of precipitation per 100 km depending on the month of the year. On the other hand, the random component ranges between 27 to 48 percent of the mean temporal variation of the monthly precipitation. This significant random spatial variability leads to large localized departures from divisional values, and clearly demonstrates the critical influence of the random component in the utilization of divisional climate forecasts for local agricultural applications. The results of this study also provide an uncertainty range for local monthly precipitation projections that are derived from divisional climate information.

Notizen: : April 1 snowpack accumulations measured at 311 snow courses in the western United States (U.S.) are grouped using a correlation-based cluster analysis. A conceptual snow accumulation and melt model and monthly temperature and precipitation for each cluster are used to estimate cluster-average April 1 snowpack. The conceptual snow model is subsequently used to estimate future snowpack by using changes in monthly temperature and precipitation simulated by the Canadian Centre for Climate Modeling and Analysis (CCC) and the Hadley Centre for Climate Prediction and Research (HADLEY) general circulation models (GCMs). Results for the CCC model indicate that although winter precipitation is estimated to increase in the future, increases in temperatures will result in large decreases in April 1 snowpack for the entire western U.S. Results for the HADLEY model also indicate large decreases in April 1 snowpack for most of the western US, but the decreases are not as severe as those estimated using the CCC simulations. Although snowpack conditions are estimated to decrease for most areas of the western US, both GCMs estimate a general increase in winter precipitation toward the latter half of the next century. Thus, water quantity may be increased in the western US; however, the timing of runoff will be altered because precipitation will more frequently occur as rain rather than as snow.

Notizen: : Downscaling coarse resolution climate data to scales that are useful for impact assessment studies is receiving increased attention. Basin-scale hydrologic processes and other local climate impacts related to water resources such as reservoir management, crop and forest productivity, and ecosystem response require climate information at scales that are much finer than current and future GCM resolutions. The Regional Climate System Model (RCSM) is a dynamic downscaling system that has been used since 1994 for short-term precipitation and streamflow predictions and seasonal hindcast analysis with good skill. During the 1997–1998 winter, experimental seasonal forecasts were made in collaboration with the NOAA Climate Prediction Center and UCLA with promising results. Preliminary studies of a control and 2°CO2 perturbation for the southwestern U.S. have been performed.

Notizen: : Climate change has the potential to have dramatic effects on the agricultural sector nationally and internationally as documented in many research papers. This paper reports on research that was focused on a specific crop growing area to demonstrate how farm managers might respond to climate-induced yield changes and the implications of these responses for agricultural water use. The Hadley model was used to generate climate scenarios for important agricultural areas of Georgia in 2030 and 2090. Linked crop response models indicated generally positive yield changes, as increased temperatures were associated with increased precipitation and CO2. Using a farm management model, differences in climate-induced yield impacts among crops led to changes in crop mix and associated water use; non-irrigated cropland received greater benefit since irrigated land was already receiving adequate moisture. Model results suggest that farm managers will increase cropping intensity by decreasing fallowing and increasing double cropping; corn acreage decreased dramatically, peanuts decreased moderately and cotton and winter wheat increased. Water use on currently irrigated cropland fell. The potential for increased water use through conversion of agriculturally important, but currently non-irrigated, growing areas is substantial.

Notizen: : We apply a physically based lake model to assess the response of North American lakes to future climate conditions as portrayed by the transient trace-gas simulations conducted with the Max Planck Institute (ECHAM4) and the Canadian Climate Center (CGCM1) atmosphere-ocean general circulation models (A/OGCMs). To quantify spatial patterns of lake responses (temperature, mixing, ice cover, evaporation) we ran the lake model for theoretical lakes of specified area, depth, and transparency over a uniformly spaced (50 km) grid. The simulations were conducted for two 10-year periods that represent present climatic conditions and those around the time of CO2 doubling. Although the climate model output produces simulated lake responses that differ in specific regional details, there is broad agreement with regard to the direction and area of change. In particular, lake temperatures are generally warmer in the future as a result of warmer climatic conditions and a substantial loss (〉 100 days/yr) of winter ice cover. Simulated summer lake temperatures are higher than 30°C over the Midwest and south, suggesting the potential for future disturbance of existing aquatic ecosystems. Overall increases in lake evaporation combine with disparate changes in A/OGCM precipitation to produce future changes in net moisture (precipitation minus evaporation) that are of less fidelity than those of lake temperature.

Notizen: Manures and fertilizers are applied to agricultural lands in excess of recommended amounts, resulting in widespread pollution of surface and ground water and contributing a substantial source of greenhouse gases associated with global warming. By developing policies that exploit the value of farm produced nutrients, input costs can be minimized. Better accounting for or crediting of farm produced nutrients is leading to economically beneficial conservation of fertilizer. In addition, hog producers who own enough land may benefit from properly managing manure nutrients. Poultry litter is valuable as fertilizer and can be marketed by independent dealers to farmers in nutrient deficit areas, with very modest assistance from the government. Dairy producers may modify their past income support programs to finance central compost facilities. Although nutrient problems were neglected in the past, recent Federal initiatives and joint initiatives with states exploit many of these and other opportunities to avoid excessive application of nutrients to the land.

Notizen: This paper details a case study of economic and natural system responses to alternative water management policies in the Cache La Poudre River basin, Colorado, 1980–1994. The case study is presented to highlight the value and application of a conceptual integration of economic, salmonid population, physical habitat, and water allocation models. Five alternative regimes, all intended to increase low winter flows, were investigated. Habitat enhancements created by alternative regimes were translated to population responses and economic benefits. Analysis concluded that instream flows cannot compete on the northern Colorado water rental market; cooperative agreements offer an economically feasible way to enhance instream flows; and establishing an instream flow program on the Cache La Poudre River mainstem is a potentially profitable opportunity. The alliance of models is a dynamic multidisciplinary tool for use in professional settings and offers valuable insight for decision-making processes involved in water management.

Notizen: A user-friendly decision support system (DSS) for long-term reservoir operation has been introduced with an eye to practical use. The system can assist reservoir managers to work out applicable rules for real-time reservoir operation. The DSS model has already been applied experimentally to the main reservoirs in Taiwan with success. In this study, Tsengwen Reservoir, the largest reservoir in Taiwan, was chosen to test the applicability of the model. The simulation results show that the DSS is not only well suited to long-term reservoir operation, but also very easily applied. A handy DSS was designed for user-friendly computer interaction with Microsoft Excel in the Windows system. Users can survey on-line reservoir operation with a browser on the World Wide Web (WWW). The uniform resource locator of the DSS is . So users may easily access the DSS via the Internet.

Notizen: Sensible (H) and latent (LE) heat fluxes, soil moisture (SM) and surface temperatures (Ts) were analyzed from seven sites at FIFE to evaluate relationships among the spatial variability of evaporative fraction, EF, SM, and the diurnal surface temperature range (Tdr). Intersite correlations between EF and Tdr were significantly negative for regional average soil moisture SMr 〈 20 percent, insignificant for 20 〈 SMr 〈 27 percent, and slightly positive for SMr 〉 27 percent. Statistical analysis of the pooled correlation coefficient between EF and Tdr for SMr 〈 20 percent indicates that it is less than zero at a very high level of significance, while the pooled correlation coefficient for regional SMr 〉 27 percent is greater than zero at the 10 percent level. The positive EF:Tdr correlations are attributed to increased surface vapor pressure at warmer sites under nearly potential conditions. These results suggest that to characterize the spatial variability of the energy budget partitioning, a variable representing the thermal response of the site should be included. An important application of these findings relates to modeling the subgrid variability of a region by subdividing the region into a few classes within which surface variables and parameters are assumed invariant. The thermal response of the surface should be included as a variable in defining these classes.

Notizen: The storage function model is a nonlinear rainfall-runoff model that has been developed for and applied to flood runoff analysis in Japan. This paper extends the model applicability by developing practical equations for estimating model parameters which are appropriate on a regional basis, i.e., so-called regional equations. Previously, the parameters were computed from historical data for a specific basin or from relationships that do not account for land use and topography.To develop the regionalized equations, model parameters were identified for 91 flood events from 22 watersheds in Japan by applying a mathematical optimization technique. Results from 39 of these events were statistically compared and regional relationships were determined as a function of land use, basin area and rainfall intensity. The utility of the estimated equations were tested by computing runoff hydrographs for lumped basins. The estimated parameters were also applied in a distributed watershed model formulation. Both applications showed acceptable results that validate the use of the regionalized relationships.

Notizen: We used a closed-ended viewer box in the measurement of Secchi depth and compared the results with simultaneous naked-eye measurements. We have shown that use of such a viewer box increases Secchi depth measurement by removing the interfering effects of water surface glare and glitter. A viewer box also increases between-observer precision. Measurements made both with and without the viewer box are slightly greater on the shady side of the boat than on the sunny side; the latter is the preferred side if Secchi data are to be related to other optical properties. As expected, the difference between viewer box and naked eye measurements increases with increasing wave height but not with increasing illuminance. Because of the lack of uniformity in the way Secchi depth is estimated, and the inherent optical problems with current Secchi depth procedures, an appeal is made for production of a standardized protocol for Secchi observations, including the use of a closed-ended viewer box on the sunny side of the boat.

Notizen: : In two workshops, we evaluated decision analysis methods for comparing Lake Erie levels management alternatives under climate change uncertainty. In particular, we wanted to see how acceptable and effective those methods could be in a public planning setting. The methods evaluated included simulation modeling, scenario analysis, decision trees and structured group discussions. We evaluated the methods by interviewing the workshop participants before and after the workshops. The participants, who were experienced Great Lakes water resources managers, concluded that simulation modeling is user-friendly enough to enable scenario analysis even in workshop settings for large public planning studies. They felt that simulation modeling can improve not only understanding of the system, but also of the options for managing it. Scenario analysis revealed that the decision for the case study, Lake Erie water level regulation, could be altered by the likelihood of climate change. The participants also recommended that structured group discussions be used in public planning settings to elicit ideas and opinions. On the other hand, the participants were less optimistic about decision trees because they felt that the public might view subjective probabilities as difficult to understand and subject to manipulation.

Notizen: : Global climate change due to the buildup of greenhouse gases in the atmosphere has serious potential impacts on water resources in the Pacific Northwest. Climate scenarios produced by general circulation models (GCMs) do not provide enough spatial specificity for studying water resources in mountain watersheds. This study uses dynamical downscaling with a regional climate model (RCM) driven by a GCM to simulate climate change scenarios. The RCM uses a subgrid parameterization of orographic precipitation and land surface cover to simulate surface climate at the spatial scale suitable for the representation of topographic effects over mountainous regions. Numerical experiments have been performed to simulate the present-day climatology and the climate conditions corresponding to a doubling of atmospheric CO2 concentration. The RCM results indicate an average warming of about 2.5°C, and precipitation generally increases over the Pacific Northwest and decreases over California. These simulations were used to drive a distributed hydrology model of two snow dominated watersheds, the American River and Middle Fork Flathead, in the Pacific Northwest to obtain more detailed estimates of the sensitivity of water resources to climate change. Results show that as more precipitation falls as rain rather than snow in the warmer climate, there is a 60 percent reduction in snowpack and a significant shift in the seasonal pattern of streamflow in the American River. Much less drastic changes are found in the Middle Fork Flathead where snowpack is only reduced by 18 percent and the seasonal pattern of streamflow remains intact. This study shows that the impacts of climate change on water resources are highly region specific. Furthermore, under the specific climate change scenario, the impacts are largely driven by the warming trend rather than the precipitation trend, which is small.

Notizen: : This paper considers the distribution of flood flows in the Upper Mississippi, Lower Missouri, and Illinois Rivers and their relationship to climatic indices. Global climate patterns including El Niño/Southern Oscillation, the Pacific Decadal Oscillation, and the North Atlantic Oscillation explained very little of the variations in flow peaks. However, large and statistically significant upward trends were found in many gauge records along the Upper Mississippi and Missouri Rivers: at Hermann on the Missouri River above the confluence with the Mississippi (p = 2 percent), at Hannibal on the Mississippi River (p 〈 0.1 percent), at Meredosia on the Illinois River (p = 0.7 percent), and at St. Louis on the Mississippi below the confluence of all three rivers (p = 1 percent). This challenges the traditional assumption that flood series are independent and identically distributed random variables and suggests that flood risk changes over time.

Notizen: : An assessment of current and future water quality conditions in the southeastern United States has been conducted using the EPA BASINS GIS/database system. The analysis has been conducted for dissolved oxygen, total nitrate nitrogen and pH. Future streamflow conditions have been predicted for the region based on the United Kingdom Hadley Center climate model. Thus far, the analyses have been conducted at a fairly coarse spatial scale due to time and resource limitations. Two hydrologic modeling techniques have been employed in future streamflow prediction: a regional stochastic approach and the application of a physically based soil moisture model. The regional model has been applied to the entire area while the physically based model is being used at selected locations to enhance and support the stochastic model. The results of the study reveal that few basins in the southeast exhibit dissolved oxygen problems, but that several watersheds exhibit high nitrogen levels. These basins are located in regions of intense agricultural activity or in proximity to the gulf coast. In many of these areas, streamflow is projected to decline over the next 30–50 years, thus exacerbating these water quality problems.

Notizen: : As part of the National Assessment of Climate Change, the implications of future climate predictions derived from four global climate models (GCMs) were used to evaluate possible future changes to Pacific Northwest climate, the surface water response of the Columbia River basin, and the ability of the Columbia River reservoir system to meet regional water resources objectives. Two representative GCM simulations from the Hadley Centre (HC) and Max Planck Institute (MPI) were selected from a group of GCM simulations made available via the National Assessment for climate change. From these simulations, quasi-stationary, decadal mean temperature and precipitation changes were used to perturb historical records of precipitation and temperature data to create inferred conditions for 2025, 2045, and 2095. These perturbed records, which represent future climate in the experiments, were used to drive a macro-scale hydrology model of the Columbia River at 1/8 degree resolution. The altered streamflows simulated for each scenario were, in turn, used to drive a reservoir model, from which the ability of the system to meet water resources objectives was determined relative to a simulated hydrologic base case (current climate). Although the two GCM simulations showed somewhat different seasonal patterns for temperature change, in general the simulations show reasonably consistent basin average increases in temperature of about 1.8–2.1°C for 2025, and about 2.3–2.9°C for 2045. The HC simulations predict an annual average temperature increase of about 4.5°C for 2095. Changes in basin averaged winter precipitation range from -1 percent to + 20 percent for the HC and MPI scenarios, and summer precipitation is also variously affected. These changes in climate result in significant increases in winter runoff volumes due to increased winter precipitation and warmer winter temperatures, with resulting reductions in snowpack. Average March 1 basin average snow water equivalents are 75 to 85 percent of the base case for 2025, and 55 to 65 percent of the base case by 2045. By 2045 the reduced snowpack and earlier snow melt, coupled with higher evapotranspiration in early summer, would lead to earlier spring peak flows and reduced runoff volumes from April-September ranging from about 75 percent to 90 percent of the base case. Annual runoff volumes range from 85 percent to 110 percent of the base case in the simulations for 2045. These changes in streamflow create increased competition for water during the spring, summer, and early fall between non-firm energy production, irrigation, instream flow, and recreation. Flood control effectiveness is moderately reduced for most of the scenarios examined, and desirable navigation conditions on the Snake are generally enhanced or unchanged. Current levels of winter-dominated firm energy production are only significantly impacted for the MPI 2045 simulations.

Notizen: : This paper reports on new methods of linking climate change scenarios with hydrologic, agricultural an water planning models to study future water availability for agriculture, an essential element of sustainability. The study is based on the integration of models of water supply and demand, and of crop growth and irrigation management. Consistent modeling assumptions, available databases, and scenario simulations are used to capture a range of possible future conditions. The linked models include WATBAL for water supply; CERES, SOYGRO, and CROPWAT for crop and irrigation modeling; and WEAP for water demand forecasting, planning and evaluation. These models are applied to the U.S. Cornbelt using forecasts of climate change, agricultural production, population and GDP growth.Results suggest that, at least in the near term, the relative abundance of water for agriculture can be maintained under climate change conditions. However, increased water demands from urban growth, increases in reservoir evaporation and increases in crop consumptive use must be accommodated by timely improvements in crop, irrigation and drainage technology, water management, and institutions. These improvements are likely to require substantial resources and expertise. In the highly irrigated basins of the region, irrigation demand greatly exceeds industrial and municipal demands. When improvements in irrigation efficiency are tested, these basins respond by reducing demand and lessening environmental stress with an improvement in system reliability, effects particularly evident under a high technology scenario. Rain-fed lands in the Cornbelt are not forced to invest in irrigation, but there is some concern about increased water-logging during the spring and consequent required increased investment in agricultural drainage. One major water region in the Cornbelt also provides a useful caveat: change will not necessarily be continuous and monotonic. Under one GCM scenario for the 2010s, the region shows a significant decrease in system reliability, while the scenario for the 2020s shows an increase.

Notizen: Watershed planning groups and action agencies seek to understand how lake water quality responds to changes in watershed management. This study developed and demonstrated the applicability of an integrated modeling approach for providing this information. An integrated model linking watershed conditions to water-quality of the receiving lake incorporated the following components: (1) an event-based AGNPS model to estimate watershed pollutant losses; (2) annualization of AGNPS results to produce annual lake pollutant loadings; (3) a base flow separation package, SAM, to estimate base flow; (4) estimates of nutrients in base flow and point sources; and (5) linkage of watershed loadings directly to EUTROMOD lake water quality algorithms. Results are presented for Melvern Lake, a 28-km2 multipurpose reservoir with a 900-km2 agricultural watershed in east central Kansas. Reasonable estimates of current lake quality were attained using an average phosphorus availability factor of 31 percent to calibrate model results to measured in-lake phosphorus. Comparison of a range of possible scenarios, including all cropland changed to no-till (best case) and all CRP and good-condition grasslands changed to cropland (worst case), indicated only a (4 percent change for in-lake phosphorus and a (2 percent change for chlorophyll a. These results indicated that this watershed is not sensitive to projected changes in land use and management.

Notizen: Data from seven Management Systems Evaluation Areas (MSEA) were used to test the sensitivity of a leaching model, Pesticide Root Zone Model-2, to a variety of hydrologic settings in the Midwest. Atrazine leaching was simulated because it was prevalent in the MSEA studies and is frequently detected in the region's groundwater. Short-term simulations used site specific soil and chemical parameters. Generalized simulations used data avail. able from regional soil databases and standardized variables. Accurate short-term simulations were precluded by lack of antecedent atrazine concentrations in the soil profile and water, suggesting that simulations using data for less than five years underestimate atrazine leaching. The seven sites were ranked in order of atrazine detection frequency (concentration 〉 0.2 μg L-1) in soil water at 2 m depth in simulations. The rank order of the sites based on long-term simulations were similar to the ranks of sites based on atrazine detection frequency from groundwater monitoring. Simulations with Map Unit Use File (MUUF) soils data were more highly correlated with ranks of observed atrazine detection frequencies than were short-term simulations using site-specific soil data. Simulations using the MIJUIF data for soil parameters were sufficiently similarity to observed atrazine detection to allow the credible use of regional soils data for simulating leaching with PRZM-2 in a variety of Midwest soil and hydrologic conditions. This is encouraging for regional modeling efforts because soil parameters are among the most critical for operating PRZM-2 and many other leaching models.

Notizen: Common carp (Cyprinus carpio) collected from four sites in the Red River of the North in 1994 were analyzed for arsenic (As), cadmium (Cd), chromium (Cr), copper (Cu), lead (Pb), nickel (Ni), selenium (So), and zinc (Zn). Concentrations differed among liver, muscle, and whole body. Generally, trace element concentrations were the greatest in livers while concentrations in whole bodies were greater than those in muscle for Cd, Cu, Ni, Pb, and Zn, and concentrations in muscle were similar to whole body for As and Se. Concentrations of Cr were lower in liver than either muscle or whole body. Correlations between liver and whole body concentrations were stronger than those between liver and muscle concentrations, but the strongest correlations were between muscle and whole body concentrations. Examination of tissue concentrations by collection sites suggested that, for a general survey, the whole body may be the most effective matrix to analyze.

Notizen: Road-related erosion was estimated by measuring 100 randomly located plots on a 180 km road network in the middle reach of R'dwood Creek in northwestern California. The estimated erosion ratn of 177 m3 km-1 was contrasted with two earlier studies in nearby parts of the same watershed. A sizable proportion of the great reduction in erosion from that reported in the earlier studies is attributed to changes in forest practice rules. Those changes have resulted in better placement and sizing of culverts and, especially, to less reliance on culverts to handle runoff from logging roads.

Notizen: Several published BOD data sets are examined to show that approximately half of them are described best in the least squares sense by treating the BOD equation as being of the three-halves order instead of first order. A dissolved oxygen (DO) sag equation for a stream is developed in which the BOD is described as a three-halves order reaction. The time when the minimum DO concentration occurs is calculated numerically. The DO sag model applied to example problems shows that an increase in the BOD reaction rate constant results in a smaller minimum DO concentration and a decrease in the time to reach the minimum DO.

Notizen: Hydrologic modeling of urban watersheds for designs and analyses of stormwater conveyance facilities can be performed in either an event-based or continuous fashion. Continuou simulation requires, among other things, the use of a time series of rainfall amounts. However, for urban drainage basins, which are typically small, the temporal resolution of the rainfall time series must be quite fine, and often on the order of 5 to 15 minutes. This poses a significant challenge because rainfall-gauging records are usually kept only for hourly or longer time steps. The time step sizes in stochastic rainfall generators are usually also too large for application to urban runoff modeling situations. Thus, there is a need for methods by which hourly rainfall amounts can be disaggregated to shorter time intervals. This paper presents and compares a number of approaches to this problem, which are based on the use of polynomial approximating functions. Results of these evaluations indicate that a desegregation method presented by Ormsbee (1989) is a relatively good performer when storm durations are short (2 hours), and that a quadratic spline-based approach is a good choice for longer-duration storms. Based on these results, the Ormsbee technique is recommended because it provides good performance, and can be applied easily to long time series of precipitation records. The quadratic spline-based approach is recommended as a close second choice because it performed the best most consistently, but remains more difficult to apply than the Ormsbee technique. Results of this study also indicate that, on average, all of the disaggregation methods evaluated introduce a severe negative bias into maximum rainfall intensities. This is cause for some well-justified concern, as the characteristics of runoff hydrographs are quite sensitive to maximum storm intensities. Thus, there is a need to continue the search for simple yet effective hourly rainfall disaggregation methods.

Notizen: We develop and compare three regression models for estimating flood quantiles at ungaged stream reaches in New Hampshire and Vermont. These models emerge from systematic analysis and validation of relations between flood magnitude and six candidate predictors reflecting basin size, topography, and climate and channel size at 36 gaging stations with record lengths exceeding 20 years. Of the candidate predictors, bank full width is most highly correlated with flood magnitude and the best prediction equation is based on width. Thus channel geometry is closely related to the current hydrologic regime in spite of geologically recent glaciation and apparently non-alluvial bank materials. We also develop models that use information obtainable from maps or GIS. The best of these uses drainage area and drainage-basin elevation as predictors, but it is substantially less precise than the width-based relation. A third relation using only drainage area as a predictor is even less precise but may be useful for some purposes. No other single predictors or combinations yielded useful predictions, although some had been included in previously-established models for the region. Model comparison included examination of residuals generated by regression using one-at-a-time suppression of data points and comparison with precision obtainable with gaging records of varying lengths.

Notizen: This study systematically evaluates residential consumer responses to a utility conservation initiative based on an econometric analysis of a sample of 510 households served by Artesian Water Company, Inc. (New Castle County of Delaware). Using a panel study approach covering the period from 1992 to 1997, this study shows that Artesian's water conservation program has had statistically significant and persistent impacts on residential water consumption.

Notizen: The City of Cedar Rapids obtains its municipal water supply from four well fields in an alluvial aquifer along the Cedar River in east-central Iowa. Since 1992, the City and the U.S. Geological Survey have cooperatively studied the groundwater-flow system and water chemistry near the well fields. The geochemistry in the alluvial aquifer near the Seminole Well Field was assessed to identify potentially reactive minerals and possible chemical reactions that produce observed changes in water chemistry. Calcite, dolomite, ferrihydrite, quartz, rhodochrosite, and siderite were identified as potentially reactive minerals by calculating saturation indexes. Aluminosiicate minerals including albite, Ca-montmorillonite, gibbsite, illite, K-feldspar, and kaolinite were identified as potentially reactive minerals using hypothetical saturation indexes calculated with an assumed dissolved aluminum concentration of 1 microgram per liter. Balanced chemical equations derived from inverse-modeling techniques were used to assess chemical reactions as precipitation percolates to the water table. Calcite dissolution was predominate, but aluminosilicate weathering, cation exchange, and redox reactions also likely occurred. Microbial-catalyzed redox reactions altered the chemical composition of water infiltrating from the Cedar River into the alluvial aquifer by consuming dissolved oxygen, reducing nitrate, and increasing dissolved iron and manganese concentrations. Nitrate reduction only occurred in relatively shallow (3 to 7 meters below land surface) groundwater near the Cedar River and did not occur in water infiltrating to deeper zones of the alluvial aquifer.

Notizen: : Water is, and most likely will continue to be, one of the main concerns and potential causes of instability in the Middle East (ME). The contribution of the existing renewable water resources is limited and can not fulfill the long-term projected gap between water supply and demand for most of the countries in the ME. An integrated regional approach for fulfilling this gap was preferred. A regional institutional framework was proposed for the implementation of this integrated regional approach and consists of a regional water board operating through three units for technical, implementation, and management aspects of project and activities. An analysis of the regional water supply and demand development, the design and policy making of the proposed institution, technology and water markets, cooperation, actors and beneficiaries, finances, and expected obstacles and constraints to the establishment and sustainable operation of the proposed institution are included.

Notizen: : A selenium budget for Lake Powell, Utah-Arizona was determined based on selenium loads at the principal stream input sites to and the output site from the lake. Based on data collected during 1985-1994, 83 percent of the selenium entering Lake Powell is accounted for at the output site. The rest of the selenium may be incorporated by lake sediment or used by the biota. Considerably more selenium per unit area is produced from the Colorado River Basin above the Colorado River-Green River confluence than from the Green River Basin and the San Juan River Basin combined. The Gunnison River Basin and the Grand Valley in Colorado produce an estimated 31 and 30 percent of the selenium that reaches Lake Powell, respectively. Irrigation-related activities are thought to be responsible for mobilizing 71 percent of the selenium that reaches Lake Powell. Selenium concentrations in water at Imperial Dam on the Colorado River upstream of the United States-Mexico international border are similar to those at the output site of Lake Powell. Therefore, most selenium observed in downstream areas of the Colorado River therefore probably is derived mostly from the Colorado River Basin above Lake Powell.

Notizen: : The Caloosahatchee River has two major sources of freshwater one from its watershed and the other via an artificial connection to Lake Okeechobee. The contribution of each source to the freshwater discharge reaching the downstream estuary varies and either may dominate. Routine monitoring data were analyzed to determine the effects of total river discharge and source of discharge (river basin, lake) on water quality in the downstream estuary. Parameters examined were: color, total suspended solids, light attenuation, chlorophyll a, and total and dissolved inorganic nitrogen and phosphorus. In general, the concentrations of color, and total and dissolved inorganic nitrogen increased, and total suspended solids decreased, as total discharge increased. When the river basin was the major source, the concentrations of nutrients (excepting ammonia) and color in the estuary were relatively higher than when the lake was the major source. Light attenuation was greater when the river basin dominated freshwater discharge to the estuary. The analysis indicates that water quality in the downstream estuary changes as a function of both total discharge and source of discharge. Relative to discharge from the river basin, releases from Lake Okeechobee do not detectably increase concentrations of nutrients, color, or TSS in the estuary.

Notizen: : Predicting stream eutrophication potential from non-point source nutrient loading across large temporal and spatial scales is a significant problem. In this paper we describe how two physiological indicators of P stress of stream bioflims, alkaline phosphatase activity (APA) and stored (surplus) P relate to two predictors of P loading: annual P loading predicted by the watershed model SIMPLE, and stream concentrations of soluble reactive P (SRP) in eight subbasins in the illinois River basin in Oklahoma. Data for APA, surplus P, nutrients and water chemistry were obtained at watershed outlets once during the cold season and twice during the warm season. There was a negative curvilinear relationship between APA and both predictors. Best fit was achieved by APA vs. annual predicted P loading. Both SRP and P. load are potentially useful to identify subbasins requiring no pollution abatement and to establish a regional target for P-load reduction. Surplus P is not as useful as APA in establishing these thresholds.

Notizen: : An experimental one-year fieldwork has been conducted in the vicinity of the Chernobyl NPP, within an agricultural watershed, to study the transfer of radionuclides brought into the environment by the disaster of 1986. Presented are results of observation of the washout of 137Cs from the runoff plot both in natural conditions and under artificial rainfalls. Beside traditional hydro-logical methods, new techniques were used allowing to consider microtopographical peculiarities of the runoff plot and their role in the redistribution of radionuclides. The estimate of the annual mass balance for the soil and the radionuclides within the runoff plot has shown that, regardless of significant areal variation of their concentration, the 137Cs washout with the solid runoff resulted from artificial rainfalls amounts to some 1 percent of its reserves in the uppermost 5 cm of the topsoil. The same parameter for the natural runoff is lower by an order of magnitude. Both these factors of self-purification are about two times less than natural radioactive decay of 137Cs.

Notizen: : Typically, infrastructure agencies build massive water projects to serve expanding populations in emerging country cities, but collect and treat only a fraction of the resulting wastewater. This effluent often overwhelms existing sewerage systems and fouls waterways. Cleaning urban waterways requires large investments over long terms and the political will to make and sustain them. This challenge - difficult in advanced countries - becomes daunting with the scarce resources and weak institutions typical of emerging countries. This paper presents a framework to structure such a strategy, and applies it to Madras, India. It consists of three parts: (1) setting a vision through a participatory process; (2) macro investments mainly in wastewater treatment that use least-cost methods; and (3) micro investments in small projects that involve local people and galvanize public support. The macro investment, $350 million for Madras, appears very large, but averages out to $66 per capita, far below the $1,000-$2,000 typical of advanced country cities. Micro projects to be undertaken by Non-Governmental Organizations (NGOs) included an independent wastewater monitoring program, sanitary upgrading of slums along waterways banks, a cattle waste demonstration project, and an industrial pollution survey. Together, a macro/micro strategy promises the funding and political will to achieve a balanced vision of waterways quality.

Notizen: : Integrated watershed management in the Lower Mississippi Alluvial Plain (Delta) requires blending federal, state, and local authority. The federal government has preeminent authority over interstate navigable waters. Conversely, state and local governments have authority vital for comprehensive watershed management. In the Delta, integrating three broad legal and administrative regimes: (1) flood control, (2) agricultural watershed management, and (3) natural resources and environmental management, is vital for comprehensive intrastate watershed, and interstate river basin management. Federal Mississippi River flood control projects incorporated previous state and local efforts. Similarly, federal agricultural programs in the River's tributary headwaters adopted watershed management and were integrated into flood control efforts. These legal and administrative regimes implement national policy largely in cooperation with and through technical and financial assistance to local agencies such as levee commissions and soil and water conservation districts. This administrative infrastructure could address new national concerns such as nonpoint source pollution which require a watershed scale management approach. However, the natural resources and environmental management regime lacks a local administrative infrastructure. Many governmental and non governmental coordinating organizations have recently formed to address this shortcoming in the Delta. With federal and state leadership and support, these organizations could provide mechanisms to better integrate natural resources and environmental issues into the Delta's existing local administrative infrastructure.

Notizen: : Australia's ‘Landcare’ program is a community-based participatory program established by government to tackle the problem of land degradation. Landcare involves thousands of Australians working together in locally based groups, tackling problems of common concern. Government and community are now looking to ‘scale up’ the Landcare idea to a regional level. State and territory governments have moved to create regional (often watershed-based) frameworks for land management planning and resource conservation, in accordance with the concept of integrated watershed management. Growing out of the success of community involvement in Landcare, many of these approaches involve the community. However scaling up of the Landcare idea introduces problems of both time and space. There have been a number of problems experienced in the implementation of Landcare and integrated watershed management. These problems include the equitable delineation of membership on decision-making bodies; the raising of sufficient funds for program implementation; and the coordination of a diversity of governmental layers, planning processes and management programs. This paper reviews how the State of Victoria has responded to these challenges and suggests what challenges remain.

Notizen: : Social scientists were included in the planning and design for an integrated, trans-basin water resource project. Within this complex project, a socioeconomic impact assessment (SIA) concentrated on identifying the social, political, and economic issues and potential impacts inherent in developing a city's water rights. Before the SIA began, some of the development alternatives had already generated widespread hostility and organized opposition from communities within the watershed. The SIA involved residents of affected communities in the study design and project planning. The study found a number of components that constituted the concerns, beliefs, and expectations about perceived, potential impacts that might result from the different alternatives. In most cases these issues constituted threats to valued environmental resources, valued community resources, the social environment, the economic base, and a secure future. The social science component was a key factor in the ultimate decision to pursue a particular alternative which was sensitive to the social and political issues, minimized environmental and socioeconomic impacts, and ultimately had support among the communities potentially affected. The experience from this case study suggests that the approach used can be applied successfully in the planning of other water development projects and result in cooperation from the wide range of interest groups that often present costly obstacles to such projects.

Notizen: : Water providers nationwide are implementing nonprice conservation measures such as education, public information, appliance retrofit and ordinances, with the expectation that these programs will reduce residential water demand. However, little empirical information exists on the effectiveness of nonprice conservation programs in reducing water demand. Previous econometric studies indicate these programs have had minimal impact. We examine the types and number of major nonprice conservation programs that have been implemented during an 11-year period in seven cities in the southwestern United States. A cross sectional, monthly time series residential water demand model, with parameters to control for variation in prices, temperature, precipitation and other factors, was used to empirically investigate the effectiveness of nonprice conservation programs in reducing water demand. We found significant reductions in use ranging between 1.1 percent and 4.0 percent per program. Because of the lack of information, we were unable to distinguish the effectiveness of individual or specific types of programs. Beyond finding that nonprice programs can be effective in reducing demand, questions regarding the efficiency and benefits to be achieved by conservation remain. As a step towards separating and evaluating the effects of individual programs, program benefits and efficiency, we recommend that utilities maintain more detailed and consistent information regarding the implementation of their nonprice programs.

Notizen: : Policy and management plans can be enhanced through effective communication between researchers and decision makers. Differences in understanding can come from differences in professional cultures. Scientists deal with facts, proof and incremental progress whereas the decision makers are often faced with perceptions, emotions and deadlines. A case study is presented illustrating the interaction between the political system and science on a water management issue. Irrigation projects in the western San Joaquin Valley of California lead to a situation requiring subsurface drainage and disposal of the drainage water. The original plan was to discharge the drainage water in the Suisun Bay east of the San Francisco Bay. Severe damage to birds associated with selenium in the water led to a reevaluation of irrigation and drainage management options. Federal and state agencies cooperated to establish a San Joaquin Valley Drainage Program (SJVDP) which was to develop plans for solving the problem. Discharge to the Bay was politically eliminated as an option for evaluation, an action criticized by a National Research Council Committee as not being scientifically based. The SJVDP published a Management Plan in 1990 which contained proposals viewed by the scientific community as not necessarily incorrect but not completely justified based on the scientific knowledge at the time. A segment of the Citizens Advisory Committee that was part of the SJVDP consisting of representatives from the interest groups viewed the Management Plan as a negotiated agreement between the environmental and agricultural interests. Presently, an Activity Plan exists, consisting of technical committees to evaluate the current technical and economic evaluation of the management options proposed in the Management Plan. This case study illustrates that factors other than scientific facts have bearing on decisions. Successful management plans must be technically sound, economically viable and socially acceptable. The scientific community needs to evaluate its role in the policy making arena and to focus research on questions of greatest value to decision makers, as well as to scientific peers.

Notizen: : To better understand the flow processes, solute-trans. port processes, and ground-water/surface-water interactions on the Santa Clara River in Ventura County, California, a 24-hour fluorescent-dye tracer study was performed under steady-state flow conditions on a 45-km reach of the river. The study reach includes perennial (uppermost and lowermost) subreaches and ephemeral subreaches of the lower Piru Creek and the middle Santa Clara River. The tracer-test data were used to calibrate a one-dimensional flow model (DAFLOW) and a solute-transport model (BLTM). The dye-arrival times at each sample location were simulated by calibrating the velocity parameters in DAFLOW. The simulations of dye transport indicated that (1) ground-water recharge explains the loss of mass in the ephemeral middle subreaches, and (2) ground-water recharge does not explain the loss of mass in the perennial uppermost and lowermost subreaches. The observed tracer curves in the perennial subreaches were indicative of sorptive dye losses, transient storage, and (or) photodecay - these phenomena were simulated using a linear decay term. However, analysis of the linear decay terms indicated that photodecay was not a dominant source of dye loss.

Notizen: : The objectives of this paper were to test the ability of various design storm distributions to simulate the actual rainfall pattern and to compare the runoff rates used in the design of stormwater management devices in the State of Florida using continuous simulation approach. The analyses were performed for four gaged stations to evaluate the applicability of design storm distributions in different parts of the State of Florida.The approach used in this study compared the peak runoff rates from design storms based on the various distributions to those that would result from actual rainfall events. A series of continuous runoff rates were developed through the use of actual fifteen-minute recorded rainfall data, Horton type infiltration decay and recovery rate, and a continuous simulation model. The runoff rates were analyzed using frequency distributions to obtain peak runoff rates associated with different return periods based on the assumption that the continuous simulation approach closely predicts the actual runoff rates from the gaged stations. The results show that the behavior of the design storm distributions varies for different watershed characteristics in different parts of the state. The study also suggests that in general the Florida Department of Transportation and the Suwanne River Water Management (FDOT/ SRWMD) distributions appeared to agree with the continuous simulation results.

Notizen: Currently no standard testing methods exist for finished products eliciting oral heat. In this study, descriptive sensory analysis was used to investigate the effects of rinsing and interstimulus time on measurements of capsaicin heat in tomato-based salsa at three oral locations (tongue, oral cavity, throat). Seven samples were tested daily with variations in intervals between stimuli (30 s, 1, 2, 4, 8, and 16 min) and with or without rinsing (crackers and water). Rinsing significantly increased repeatability and increased the rate of heat decay across all loci. An exponential heat decay was observed. Tongue heat was significantly higher than oral cavity and throat burn, and slight sensitization and desensitization occurred with short and long interstimulus times, respectively. This study showed that seven samples of medium-heat salsa could be tested daily with at least 16 min between samples and liberal rinsing with crackers and water.

Notizen: The present study examined the effect of two different processing technologies in the manufacture of a ewe's-milk cheese. Two batches were manufactured, one from raw milk, the other from pasteurized milk. A starter culture consisting of Lactococcus lactis subsp. lactis var. diacetylactis and Lactobacillus casei subsp. casei was added to both batches. Descriptive analysis of the sensory characteristics was carried out for the two cheese batches at two different ripening times (90 and 180 days).Statistical analysis revealed differences both between the two batches and between the ripening times considered. The cheeses made from the raw milk were firmer, with a more characteristic odor, taste, and aftertaste. The cheeses made from the pasteurized milk were creamier with a sweeter odor and taste and a more bitter aftertaste. Irrespective of the cheese batch, at 180 days all the cheese samples were firmer and grainier with a more characteristic taste and aftertaste as well as a spicier taste and aftertaste.

Notizen: Ewes milk cheeses have a special taste and flavor, very different from that of cheeses made from cows milk. A new descriptive and discriminative language and the corresponding set of standard references for evaluating the main sensory characteristics of ewes cheeses were developed. Two multivariate statistical procedures, Stepwise Discriminant Analysis (SDA) and Principal Component Analysis (PCA) were applied during the development and selection of the sensory attributes.The list of terms and references selected should help researchers elucidate the factors influencing typical odor, flavor and texture development in these cheese varieties, and improve sensory quality in cheese factories. The aim of the present study was the development of a preliminary lexicon and standard references for ewes milk cheeses. To achieve this goal a statistical method has been proposed to select the most adequate ewes milk cheese sensory terms.

Notizen: The objective of this study was to compare the differences in aroma of cooked rice samples. The rice aroma of four popular rice varieties in Taiwan (TC 189, TNu 70, TNu 67 and TC Sen 10) at different temperatures (18C, 25C and 60C) were analyzed by GC-MS system (using headspace capture collection) and evaluated by trained and naive panels. The GC-MS results indicated that the composition of the volatile components of rice was complicated and no single volatile compound contributed to the characteristics of rice aroma. Fourteen attributes were developed using modified quantitative descriptive analysis and evaluated with line scaling method. The 60C samples were higher in hot-steam-bread aroma, corn aroma, corn-leaf aroma and brown-rice aroma, while the 18C samples were higher in cold-steam-bread aroma and fermented-sour aroma. Compared to the other varieties, the TC Sen 10 was uniquely higher in plastic aroma, sulfur aroma and gasoline aroma. As expected, hedonic results showed that naive panelists preferred the overall aroma perception of the 60C samples. The relationship between the volatile compounds and descriptive attributes is discussed.

Notizen: This study's objective was to study how much the salt (NaCl) content of cooked sausage can be reduced without violating the perceived taste pleasantness. The 34 assessors evaluated seven cooked sausages made with added salt concentrations of 1.05; 1.20; 1.35; 1.50; 1.65; 1.80 and 1.95%. A relative-to-standard scale was used for rating the saltiness and taste pleasantness. The saltiness and pleasantness intensity of different salt concentrations was rated against a reference sausage, which contained 1.5% added salt. A reference sample was also hidden among the samples. The assessors were able to rank sausages based on the saltiness into the right order. Based on taste pleasantness, there was no significant difference between the sausages made with 1.35; 1.50; 1.65; 1.80 or 1.95% added salt (p〉0.05). Several differences were, however, detected among the saltiness levels. The results of this study suggest that it might be possible to reduce the salt content of cooked sausage to 1.35% added salt.

Notizen: The effects of product information on responses to frankfurter sausages and chocolate bars were studied by comparing sensory and hedonic ratings in two conditions: blind tasting and tasting with information present. Furthermore, the effect of information alone was investigated by having the subjects rate the expected sensory and hedonic intensities of the products on the basis of packages with different claims. Three groups of subjects were tested by giving them different information: The basic group (no added claims, n=31), the reduced-fat group (products claimed to have reduced-fat, n=29) and the flavorful group (products claimed to have full meat/chocolate flavor, n=31). Product information increased the rated pleasantness of the frankfurter in all three information groups compared to the blind ratings. The information did not affect the pleasantness of the chocolate bars. The expected attribute intensities of the frankfurters and chocolates were rated lower by the reduced-fat group than by the other groups. Overall, the effect of product information was more clearly seen in ratings of sensory attributes than in pleasantness ratings.

Notizen: Studies of the repeatability and the homogeneity of expert panel scores in sensory profiling show that lasting and reliable evaluations of food products are difficult to obtain: strong inter- and intra-individual differences are commonly observed. Our hypothesis is that this variability is due to quantification methods that consist of asking panelists to furnish quantitative values (by attributing a numerical point to perceived intensity) and that using natural language in the form of verbal judgements in a hierarchical tree would allow improving the reliability of sensory evaluations. This hypothesis was tested by comparing a numerical value scale and a specific hierarchical semantic scale that subjects devised themselves prior to the experiment. The products (chocolate dessert creams) were evaluated using each of the two methods. The results show that the capacity to discriminate between products is better when verbal judgements are used. We discuss the advantages of hierarchical semantic scales for sensory profiling.

Notizen: Thirty Burgundy Pinot noir wines were evaluated by quantitative descriptive profile by nose (BN) and by mouth (BM) separately, by a trained panel composed of 12 judges. A specific vocabulary of 20 terms was developed. Sensory results were analyzed and compared by univariate and multivariate statistical techniques. Principal component analyses of the mean ratings BN and BM were fairly comparable regarding correlation among variables and the position of the wines. However, five sensory characteristics seem to be more intensely perceived BM, against 6 BN. Panel discrimination of the wines and panel repeatability in the measure were found to be slightly better BN than BM. A further canonical discriminant analysis on the data confirmed that panelists could well differentiate groups of wines from the same winemaker, probably corresponding to different style of winemaking.

Notizen: The aim of this work was to develop a new modeling method of time-intensity curves by utilizing the simple shape of a trapezoid. Using a computerized procedure, time-intensity data were collected from panelists evaluating sensory attributes of ice creams. The method was based on the extraction of four values on the time axis, corresponding to 5 and 90% of the maximum intensity value, both in the increasing and decreasing phases of the curve. These intensity levels were chosen because they permitted to rub out some artifacts for intensities close to zero and in the maximum intensity plateau region. Kinetic parameters (duration and rate of the increasing and decreasing phases of the sensation, duration of the maximum intensity) were calculated from the coordinates of the trapezoid, allowing to differentiate ice creams. They were found to bring complementary information in comparison with traditional intensity scaling. In the present paper, the fat content was identified as modifier of the maximum fruitiness intensity of ice creams and of the kinetic of flavor release.

Notizen: 3-AFC discrimination tests between‘threshold’concentration NaCl solutions and purified water stimuli were performed using a variety of interstimulus rinsing regimes to test predictions of test sensitivity based on the Sequential Sensitivity Analysis model. Superior performance on triads with NaCl as the‘odd’stimulus, over triads with water as the‘odd’stimulus, confirmed earlier research. It was possible, using SSA predictions, to find the right combination of rinses, to arrange for either set of triads to elicit strongly superior performance from judges. This manipulation was predicted by SSA but not by an unequal variance Thurstonian model. Failure of some SSA predictions highlighted the notion of stimulus enhancement by adaptation, leading to a modification of the model. Such manipulation of interstimulus rinses could form the basis for increasing or decreasing test sensitivity.

Notizen: A visual profile panel (27 assessors) was developed for the evaluation of color and appearance properties of chilled dairy dessert gel products based on the Quantitative Descriptive Analysis (QDA) method (Stone et al. 1974). In the terminology development stage of the training procedure, assessors agreed on 29 visual cues to be used in the evaluation of chilled dairy desserts. Further training were based on these cues. Panel performance was analyzed using principal component analysis (PCA) and generalized Procrustes analysis (GPA). The panel exhibited good consensus over most of the color and appearance attributes with better agreement in attributes related to visual texture and flavor over color, gloss and opacity attributes. Assessors also displayed the ability to visually evaluate and discriminate between samples without the need to taste, smell nor touch.

Notizen: Influence of strain association, temperature, pH and storage on the sensory properties of low fat stirred yogurt was studied through a factorial design including three associations of thermophilic lactic acid bacteria (one Lactobacillus delbrueckii subsp. bulgaricus, one ropy and one nonropy Streptococcus thermophilus strains), three incubation temperatures (39C, 42C and 45C), two final fermentation pH (4.4 and 4.8) and two storage times (7 and 21 days). The 36 formulated yogurts were assessed by Quantitative Descriptive Analysis and by instrumental measurements: apparent viscosity (modified funnel of Posthumus), lactate and pH. Texture perceptions and acid taste, rather than other flavor properties, gave the best discrimination between samples according to strain association, temperature and final pH. Significant two-factor interaction displayed the concomitant influence of strain association and temperature on the sample texture properties. Instrumental parameters correlated best with thickness and acid taste (pH and lactate) and mouthcoating (apparent viscosity).

Notizen: Fourteen samples of instant cocoa drinks with different compositions of main ingredients (cocoa, milk, sugar) and stabilizer content were evaluated by a trained sensory panel. Fifteen sensory attributes concerning appearance, odor, texture and flavor were evaluated with focus on the complex term mouthfeel. The sensory properties of the cocoa drinks were related to measured physical, chemical and rheological properties by means of Partial Least Squares Regression. A high positive covariation was revealed between sensory and rheological measured viscosity properties. Mouthfeel in cocoa drinks was found to depend on both viscosity and flavor properties. These findings suggest that in addition to the prevailing ISO definition of mouthfeel, which is limited to a description of tactile characteristics, interaction with flavor may be included. Both stabilizer and main ingredients were shown to have distinct effects on the sensory properties. A consumer test showed a negative correlation between mouthfeel and consumer preference, within the range of cocoa drinks studied.

Notizen: The objective of this study was to observe the impact of a perceptible difference in the liking of milk on consumption of the milk in both laboratory and cafeteria settings. We produced milk with no flavor defects and milk with a light oxidized flavor. The defect-free milk scored about 1 point higher than the off-flavored milk on a 9-point hedonic scale. We placed the same two milk products in the milk dispenser in a dormitory cafeteria for a total of 32 dinner meals and measured the amount of milk consumed. A subset of subjects from the cafeteria population also consumed the milks in a laboratory consumption test. In a second laboratory consumption test a different group of subjects consumed the two milks. The liking difference had no impact on consumption in the dormitory food service setting and either no impact or a small impact on consumption in a laboratory setting.

Notizen: Panelists with computer experience (n = 24) and without (n = 26) rated three foods representing liked, neutral and disliked categories using a 9-point hedonic scale on computer and paper ballots. In paired t-test results between computer and ballot ratings, no differences were found in overall acceptance, flavor and appearance attributes. Regression analysis indicated a significant (p〈0.01) linear relationship between computer and paper ballot ratings. Computer ballot ratings for overall acceptance were comparable to paper ballot ratings in a consumer sensory evaluation test. Slight differences in overall acceptance were found between computer and paper ballot responses from panelists with and without computer experience. GLM indicated the group without computer experience rated overall acceptance and flavor attributes for cereal, and appearance and flavor attributes for potato chips significantly higher (p〈0.05) than panelists with computer experience.

Notizen: Hand evaluation and mouth evaluation were compared for texture of cheese. Panelists (n = 11) identified seven mouth terms and five hand terms and developed definitions and standard procedures for evaluation during the course of training. The terms were used to evaluate texture properties of fourteen different types of natural and processed full fat and reduced fat cheeses. Hand and mouth evaluation were able to discriminate cheese texture (P≦0.05). Principal component analysis of data revealed that hand and mouth evaluation differentiated the cheeses in a similar manner. Correlation analysis, factor analysis, and canonical analysis revealed that mouth and hand terms were highly correlated (P≦0.05). Either hand or mouth evaluation can be used to discriminate cheese texture.

Notizen: Three groups of ten naive assessors were recruited to perform an odor profiling of 10 orange juices using 8 odor descriptors. These panels differed on the way they learned each descriptor. Group 1R learned to match one descriptor with one external standard; group 3R learned to associate one descriptor with 3 external standards; group OR defined by itself the 8 descriptors from a set of orange juices. Results showed that the use of one standard per descriptor seemed to be only efficient when the standard was typical of the odor perception in the orange juices. Learning one odor concept with 3 standards led to redundant use of discriminant descriptors and failed on the agreement among assessors. Finally, group OR was a discriminant as well a homogenous panel.

Notizen: Research on the power of discrimination methods in difference and preference tests has both theoretical and practical significance. Power is important to evaluate the sensitivities of tests and determine sample size. Ennis and Bi (1998, 1999) proposed the beta-binomial distribution to model replicated difference and preference tests with inter-trial variation and analyzed in general the power of the tests. In this paper, the power of discrimination methods for replicated difference and preference tests is discussed further. The equations for calculating power for methods based on the BB model are given. Examples with tables and charts for calculating and comparing the power of the methods are also given.

Notizen: Ennis and Bi (1998) discussed the beta-binomial (BB) model for replicated difference and preference tests. Based on the BB model, tables of the minimum number of choice responses to achieve significance at α≦ 0.05 are provided for replicated 2-AFC, Duo-Trio, 3-AFC and Triangular tests. The theory underlying the tables, how to use the tables, as well as some examples to illustrate their use are given. The tables can be used to evaluate the results of replicated difference and preference tests using forced choice methods.

Notizen: This paper describes an initial but fundamental attempt to lay some groundwork for a fuzzy-set-based paradigm for sensory analysis and to demonstrate how fuzzy set and neural network techniques may lead to a natural way for sensory data interpretation. Sensory scales are described as fuzzy sets, sensory attributes as fuzzy variables, and sensory responses as sample membership grades. Multi-judge responses are formulated as a fuzzy membership vector or fuzzy histogram of response, which gives an overall panel response free of the unverifiable assumptions implied in conventional approaches. Neural networks are used to provide an effective tool for modeling and analysis of sensory responses in their naturally fuzzy and complex forms. A maximum method of defuzzification is proposed to give a crisp grade of the majority opinion. Two applications in meat quality evaluation are used to demonstrate the use of the paradigm and procedure. It is hoped that this work will bring up some new ideas and generate interest in research on application of fuzzy sets and neural networks in sensory analysis.