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Quality Differences (quality + difference)
Selected AbstractsIncreased survival and breeding performance of double breeders in little penguins Eudyptula minor, New Zealand: evidence for individual bird quality?JOURNAL OF AVIAN BIOLOGY, Issue 2 2003Edda Johannesen The little penguin Eudyptula minor is unique among penguin species in being able to fledge chicks from two clutches in one breeding season. Pairs laying two clutches in a given season make a higher reproductive investment, and may be rewarded by a higher reproductive success as they may raise twice as many chicks as pairs laying one clutch. The higher effort made by pairs laying two clutches could correlate negatively with survival, future reproductive performance or offspring survival, indicating a cost of reproduction. Conversely, a positive relationship between the number of clutches produced in a given breeding season and survival, future reproductive performance or offspring survival would indicate that birds laying two clutches belonged to a category of birds with higher fitness, compared to birds laying only one clutch in the season. In this study we used a long-term data set taken from an increasing population of little penguins in Otago, SE New Zealand. We modelled the relationship between the number of clutches laid in a breeding season and survival probability, reproductive performance in the next breeding season and first year survival of offspring using capture-recapture modelling. Birds laying two clutches produced 1.7 times more fledglings during a breeding season than pairs laying one clutch. We found that birds laying two clutches had a higher probability of breeding in the following breeding season, a higher probability of laying two clutches in the following breeding season and a higher survival probability. There was no overall difference in post-fledging survival between the young of birds producing one clutch and the young of birds producing two clutches. However, the survival of young of single clutch breeders declined with laying date, whereas the young of double clutch breeders had the same survival rate irrespective of laying date. For a subset of data with birds of known age, we found evidence that the probability of laying two clutches increased with age. However, there were also indications for differences among birds in the tendency to lay two clutches that could not be attributed to age. We tentatively interpret our results as evidence of quality difference among little penguin breeders. [source] Interactions between dispersal, competition, and landscape heterogeneityOIKOS, Issue 7 2007Ace North It is widely acknowledged that space has an important role in population regulation, yet more specific knowledge into how the relevant factors interact attains little consensus. We address this issue via a stochastic, individual based model of population dynamics, in a continuous space continuous time framework. We represent habitat quality as a continuously varying surface over the two-dimensional landscape, and assume that the quality affects either fecundity (rate of propagule production) or probability of propagule establishment. We control the properties of the landscape by two parameters, which we call the patch size (the characteristic length scale in quality variation), and the level of heterogeneity (the characteristic quality difference between poor quality and high quality areas). In addition to such exogenous variability, we also account for endogenous factors causing spatial variation by assuming localised dispersal and competition. We find that heterogeneity has a general positive effect on population density, and hence it is beneficial to improve best quality habitat at the expense of worst quality habitat. With regards to patch size, we find an intermediate optimum, due to a conflict between minimising the loss of propagules to low quality regions and maximising the benefits of heterogeneity. We address the consequences of regional stochasticity by allowing the environmental conditions change in time. The cost of having to continuously track where the favourable conditions have moved to ultimately reduces population size. [source] How Consistently are Good Parents Good Parents?ETHOLOGY, Issue 4 2003Passer domesticus, Repeatability of Parental Care in the House Sparrow In many avian species, substantial individual variation occurs in parental food-provisioning levels, which often is assumed to reflect variation in parental quality. Parental quality also has often been invoked as a key element in mate choice among biparental species, and many sexually-selected traits have been investigated as potential predictors of parental quality. In recent studies of house sparrow (Passer domesticus) parents, we found that individuals behaved remarkably consistently across time, regardless of temporary manipulations of the nestling provisioning of their partners. This suggests that variation in parental competence may be attributable to quality differences among individuals. One prediction of the ,parental quality differences' hypothesis is that individuals also should show consistency in their provisioning behavior across broods. To test this, we compared the parental delivery rates of individual house sparrows across broods. Parents of both sexes reduced their per-chick delivery rates as the season progressed; parents of both sexes were also responsive to changes in their brood sizes. Despite these sources of environmental variation in provisioning rates, the parental care of individual males was highly repeatable across broods. By contrast, female parental care showed extremely low repeatability, and standardized measures of among-individual variation in parental behavior revealed females to be much less variable than males. These results indicate that females in this multi-brooded species have much to gain from mate-choice decisions predicated on male parental quality or accurate indicators of such, whereas males are less likely to profit from being highly selective about the ,parental quality' of their partners. [source] Does Prospective Payment Really Contain Nursing Home Costs?HEALTH SERVICES RESEARCH, Issue 2 2002Li-Wu Chen Objective. To examine whether nursing homes would behave more efficiently, without compromising their quality of care, under prospective payment. Data Sources. Four data sets for 1994: the Skilled Nursing Facility Minimum Data Set, the Online Survey Certification and Reporting System file, the Area Resource File, and the Hospital Wage Indices File. A national sample of 4,635 nursing homes is included in the analysis. Study Design. Using a modified hybrid functional form to estimate nursing home costs, we distinguish our study from previous research by controlling for quality differences (related to both care and life) and addressing the issues of output and quality endogeneity, as well as using more recent national data. Factor analysis was used to operationalize quality variables. To address the endogeneity problems, instrumental measures were created for nursing home output and quality variables. Principal Findings. Nursing homes in states using prospective payment systems do not have lower costs than their counterpart facilities under retrospective cost-based payment systems, after quality differences among facilities are controlled for and the endogeneity problem of quality variables is addressed. Conclusions. The effects of prospective payment on nursing home cost reduction may be through quality cuts, rather than cost efficiency. If nursing home payments under prospective payment systems are not adjusted for quality, nursing homes may respond by cutting their quality levels, rather than controlling costs. Future outcomes research may provide useful insights into the adjustment of quality in the design of prospective payment for nursing home care. [source] Effects of urbanization on stream water quality in the city of Atlanta, Georgia, USA,HYDROLOGICAL PROCESSES, Issue 20 2009Norman E. Peters Abstract A long-term stream water quality monitoring network was established in the city of Atlanta, Georgia during 2003 to assess baseline water quality conditions and the effects of urbanization on stream water quality. Routine hydrologically based manual stream sampling, including several concurrent manual point and equal width increment sampling, was conducted ,12 times annually at 21 stations, with drainage areas ranging from 3·7 to 232 km2. Eleven of the stations are real-time (RT) stations having continuous measures of stream stage/discharge, pH, dissolved oxygen, specific conductance, water temperature and turbidity, and automatic samplers for stormwater collection. Samples were analyzed for field parameters, and a broad suite of water quality and sediment-related constituents. Field parameters and concentrations of major ions, metals, nutrient species and coliform bacteria among stations were evaluated and with respect to watershed characteristics and plausible sources from 2003 through September 2007. Most constituent concentrations are much higher than nearby reference streams. Concentrations are statistically different among stations for several constituents, despite high variability both within and among stations. Routine manual sampling, automatic sampling during stormflows and RT water quality monitoring provided sufficient information about urban stream water quality variability to evaluate causes of water quality differences among streams. Fecal coliform bacteria concentrations of most samples exceeded Georgia's water quality standard for any water-usage class. High chloride concentrations occur at three stations and are hypothesized to be associated with discharges of chlorinated combined sewer overflows, drainage of swimming pool(s) and dissolution and transport during rainstorms of CaCl2, a deicing salt applied to roads during winter storms. One stream was affected by dissolution and transport of ammonium alum [NH4Al(SO4)2] from an alum-manufacturing plant; streamwater has low pH (<5), low alkalinity and high metals concentrations. Several trace metals exceed acute and chronic water quality standards and high concentrations are attributed to washoff from impervious surfaces. Published in 2009 by John Wiley & Sons, Ltd. [source] Rearing conditions determine offspring survival independent of egg quality: a cross-foster experiment with Oystercatchers Haematopus ostralegusIBIS, Issue 2 2006MARTIJN VAN DE POL Variation in rearing conditions, due either to parental or to environmental quality, can result in offspring of different quality (e.g. body condition, immune function). However, evidence is accumulating that egg size and composition can also affect offspring quality. In Oystercatchers Haematopus ostralegus, high-quality rearing conditions result in a higher quantity as well as quality of offspring. This is thought to be caused by increased parental food provisioning to the chicks in high-quality environments. However, variation in egg quality between rearing conditions could also affect the quantity and quality of offspring. Determining the mechanism and ontogeny of quality differences is important in unravelling the causes of variation in reproductive success. To disentangle the effects of egg quality, and quality of the rearing conditions, on the future survival of offspring, we cross-fostered complete clutches between nests. When reared under conditions of similar environmental quality, chicks originating from eggs laid in low-quality environments survived as well as chicks originating from eggs laid in a high-quality environment. However, chicks reared in high-quality environments survived twice as long as chicks reared in low-quality environments, independent of the environmental quality in which the eggs were laid. This suggests that variation in the future survival of offspring is primarily caused by differences in environmental and/or parental quality, with no clear effect of egg quality (size). [source] Characterization of blond and Star Ruby (red) Jaffa grapefruits using antioxidant and electrophoretic methodsINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 3 2006Shela Gorinstein Summary Antioxidant and electrophoretic methods were used to characterize the quality differences between blond and Star Ruby (red) grapefruits. Dietary fibre, minerals and trace elements, total polyphenols, anthocyanins, flavonoids, phenolic and ascorbic acids were also determined. The antioxidant potential of red grapefruit was significantly higher than that of the blond fruit (P < 0.05) and correlated well with the total polyphenols (R2 from 0.8456 to 0.9711). In both the cultivars studied, thirty-two electrophoretic bands were detected [sodium dodecyl-polyacrylamide gel eletrophoresis (SDS-PAGE)]. The main electrophoretic bands occurred between 20 and 43 kDa in both grapefruits with few minor differences between the varieties. Our findings indicate the following (i) red grapefruit is preferable: it has a higher concentration of bioactive compounds and antioxidant potential than the blond; (ii) 1, 1-diphenyl-2-picrylhydrazyl (DPPH) test is a more sensitive method for the determination of antioxidant potential; (iii) there are some minor differences in electrophoretic patterns; (iv) antioxidant and electrophoretic methods are a good combination for characterization of differences of the same citrus fruits. [source] Quality improvement through consumer sorting and disposalAGRIBUSINESS : AN INTERNATIONAL JOURNAL, Issue 4 2009Peyton Ferrier Sorting allows consumers to capture the value of quality differences. As higher quality goods are removed, the value of the seller's remaining stock falls, lowering the price and profits. Bundling and other marketing mechanisms can discourage sorting and prevent the depreciation of the seller's stock. With comparative statics and simulations, the author shows that sellers can increase expected quality and profits by committing to discard a proportion of their resale stock after sorting occurs. In this manner, sorting acts similarly to agricultural grading. [EconLit Classification: Q1, Q11, Q13, L0, L1, D8, D82]. © 2009 Wiley Periodicals, Inc. [source] Physicochemical Characterization and Consumer Acceptance by Asian Consumers of Aromatic Jasmine RiceJOURNAL OF FOOD SCIENCE, Issue 1 2004S. SUWANSRI ABSTRACT: Physicochemical properties and acceptance by Asian consumers in the United States of 3 commercially U. S.-grown and 12 imported jasmine rice samples were evaluated. Rice kernels, flour, and starch were characterized for physical, chemical, pasting, and thermal properties. Amylose content, gel type, hardness-to-stickiness ratio, surface fat, protein, and pasting properties significantly affected the eating and cooking qualities and physical appearances of the rice samples; these variables were key to distinguishing the major quality differences and to differentiating U. S.-grown from imported jasmine rice. Data collected from this study could be useful to rice producers, importers, or rice breeders for understanding the physicochemical characteristics of aromatic jasmine rice and its acceptance by Asian consumers. [source] Sherry wine vinegar: physicochemical changes during the acetification processJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 7 2001L Morales Abstract The quality of a wine vinegar is determined by the raw wine substrate and the acetification process employed in its production. Attempts to characterise vinegars have been based on these two features, along with variables such as total extract, glycerol, organic acids, volatile compounds and phenolic composition. When the final products are analysed, it is difficult to evaluate to what extent quality differences are due to the raw material or to differences in production methods, so it is necessary to determine the influence of each feature separately. The present work focuses on monitoring physicochemical changes during the acetification of sherry wine by submerged culture. ANOVA showed significant differences for ethanol, acetic and lactic acids and some volatile compounds (methanol, 1-propanol, 2-methyl-1-propanol, 2-methyl-1-butanol, 3-methyl-1-butanol, acetoin, acetaldehyde, ethyl acetate and ethyl lactate). However, no statistical changes were found for phenolic compounds during acetification. The phenolic composition of the final product was determined by the substrate employed. In addition, the influence of cycle duration on the chemical composition was studied; the only compound affected by this factor was 2-methyl-1-butanol. © 2001 Society of Chemical Industry [source] Superstar Effects in Deluxe Gastronomy , An Empirical Analysis of Value Creation in German Quality RestaurantsKYKLOS INTERNATIONAL REVIEW OF SOCIAL SCIENCES, Issue 4 2009Thomas Ehrmann Summary We analyze whether superstar effects (disproportionate income effects) exist in the deep-pocket market for quality gastronomy in Germany, and what factors determine the stars' rents. In quality gastronomy, the stars can be the restaurant chefs. Building on Rosen's (1981) and Adler's (1985) central theories on star effects, we explore two potential sources of stardom. Following Rosen (1981), we test if quality differences between the chefs' performances have a direct effect on financial rewards ("direct superstar effect"). Following Adler (1985), we assess the income effect of a media presence of chefs ("classical Superstar effect"). Through this, we deal with an economic issue of general interest: does it pay more to develop your skills in your core business to perfection, or to maintain the current level of skills and invest in self-marketing? Analyzing a sample of 288 restaurants, for potential star effects by differences in quality, we find that higher quality increases chefs' revenues. Yet, revenues do not increase disproportionately, and achieving higher quality requires substantial investments in exquisite ingredients, excellent staff and prime ambience. This problem, also called the "agony of the stars", has manifested itself in the bankruptcies of European three-star restaurants in recent years. As regards potential star effects by differences in media presence, we observe a positive impact of TV appearances on financial rewards. Yet, these income effects are moderate as well, so there is neither a direct, nor a classical superstar effect in quality gastronomy. We argue that although both perfection of skills and self-marketing have similarly positive income effects, self-marketing seems both the less risky and the less stressful way to enhance income. [source] The comparative advantage of public ownership: evidence from U.S. electric utilitiesCANADIAN JOURNAL OF ECONOMICS, Issue 2 2005John E. Kwoka Jr This paper draws on theory suggesting that public enterprise may have an advantage in producing goods and services whose quality attributes are difficult to specify a priori. Using a comprehensive data set of U.S. electric utilities to estimate cost functions, we find that while privately owned systems achieve lower costs in generation, public systems generally have an advantage in the end-user-oriented distribution function with its more non-contractible quality attributes. Other evidence on quality differences by ownership type and by enterprise size supports this distinction. JEL classification: L33, L94 L'avantage comparatif de la propriété publique : résultats pour la production d'électricité auxEtats-Unis., Les études de la performance des entreprises publiques et privées ont produit des résultats qui ne sont pas déterminants. Ce mémoire se fonde sur la théorie qui suggère que l'entreprise publique peut avoir un avantage dans la production de biens et services dont la qualité est difficile à définir a priori. A partir de données extensives sur les producteurs d'électricité aux Etats-Unis, on définit des fonctions de coûts. Il appert que, quand ils sont entre des mains privées, les systèmes de production réussissent à obtenir des coûts de génération plus bas; d'autre part, les systèmes publics ont un avantage pour ce qui est de la fonction de distribution orientée vers les besoins de l'usager à cause des attributs de qualité plus difficiles à contractualiser. D'autres résultats quant aux différences de qualité par types de propriété et par tailles d'entreprises viennent confirmer l'importance de cette distinction. [source] | ||||||||||||||||