3,213 research outputs found

    Spatial Competition in Private Labels

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    Previous studies find that private labels increase retailers' bargaining power with manufacturers and allow retailers to price discriminate. We use a spatial discrete choice model to show that retailers also use store brands to create market power through store differentiation, but not as a means of building market share.Marketing,

    OBESITY AND HYPERBOLIC DISCOUNTING: AN EXPERIMENTAL ANALYSIS

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    Behavioral economists maintain that addictions such as alcoholism, smoking and over-eating represent examples of present-bias in decision making that is fundamentally irrational. In this article, we develop a model of present bias and apparently hyperbolic discounting that is fully consistent with rational behavior. We construct an experiment to test our hypothesis and to determine whether discount rates differ for individuals who engage in behaviors that could endanger their health. Our results show that discount functions are quasi-hyperbolic in shape, and that obesity and drinking are positively related to the discount rate. Anti-obesity policy, therefore, would be best directed to informing individuals as to the long-term implications of short-term gratification, rather than taxing foods directly.addiction, discounting, experiments, hyperbolic, obesity, time-inconsistency, Agricultural and Food Policy, Consumer/Household Economics, Demand and Price Analysis, Food Consumption/Nutrition/Food Safety, Food Security and Poverty, Health Economics and Policy, C91, D12, D91, I18,

    Obesity and Hyperbolic Discounting: An Experimental Analysis

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    Behavioral economists maintain that addictions such as alcoholism, smoking and over-eating represent examples of present-bias in decision making that is fundamentally irrational. In this article, we develop a model of present bias and apparently hyperbolic discounting that is fully consistent with rational behavior. We construct an experiment to test our hypothesis and to determine whether discount rates differ for individuals who engage in behaviors that could endanger their health. Our results show that discount functions are quasi-hyperbolic in shape, and that obesity and drinking are positively related to the discount rate. Anti-obesity policy, therefore, would be best directed to informing individuals as to the long-term implications of short-term gratification, rather than taxing foods directly.addiction, discounting, experiments, hyperbolic, obesity, time-inconsistency., Consumer/Household Economics, Food Consumption/Nutrition/Food Safety, Health Economics and Policy, Institutional and Behavioral Economics, C91, D12, D91, I18.,

    Multi-wavelength Radio Continuum Emission Studies of Dust-free Red Giants

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    Multi-wavelength centimeter continuum observations of non-dusty, non-pulsating K spectral-type red giants directly sample their chromospheres and wind acceleration zones. Such stars are feeble emitters at these wavelengths however, and previous observations have provided only a small number of modest S/N measurements slowly accumulated over three decades. We present multi-wavelength Karl G. Jansky Very Large Array thermal continuum observations of the wind acceleration zones of two dust-free red giants, Arcturus (Alpha Boo: K2 III) and Aldebaran (Alpha Tau: K5 III). Importantly, most of our observations of each star were carried out over just a few days, so that we obtained a snapshot of the different stellar atmospheric layers sampled at different wavelengths, independent of any long-term variability. We report the first detections at several wavelengths for each star including a detection at 10 cm (3.0 GHz: S band) for both stars and a 20 cm (1.5 GHz: L band) detection for Alpha Boo. This is the first time single luminosity class III red giants have been detected at these continuum wavelengths. Our long-wavelength data sample the outer layers of Alpha Boo's atmosphere where its wind velocity is approaching its terminal value and the ionization balance is becoming frozen-in. For Alpha Tau, however, our long-wavelength data are still sampling its inner atmosphere, where the wind is still accelerating probably due to its lower mass-loss rate. We compare our data with published semi-empirical models based on ultraviolet data, and the marked deviations highlight the need for new atmospheric models to be developed. Spectral indices are used to discuss the possible properties of the stellar atmospheres, and we find evidence for a rapidly cooling wind in the case of Alpha Boo. Finally, we develop a simple analytical wind model for Alpha Boo based on our new long-wavelength flux measurements

    Outer-Sphere Effects on Reduction Potentials of Copper Sites in Proteins: The Curious Case of High Potential Type 2 C112D/M121E Pseudomonas aeruginosa Azurin

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    Redox and spectroscopic (electronic absorption, multifrequency electron paramagnetic resonance (EPR), and X-ray absorption) properties together with X-ray crystal structures are reported for the type 2 Cu^(II) C112D/M121E variant of Pseudomonas aeruginosa azurin. The results suggest that Cu^(II) is constrained from interaction with the proximal glutamate; this structural frustration implies a “rack” mechanism for the 290 mV (vs NHE) reduction potential measured at neutral pH. At high pH (~9), hydrogen bonding in the outer coordination sphere is perturbed to allow axial glutamate ligation to Cu^(II), with a decrease in potential to 119 mV. These results highlight the role played by outer-sphere interactions, and the structural constraints they impose, in determining the redox behavior of transition metal protein cofactors

    Testosterone Influence on Gene Expression in Lacrimal Glands of Mouse Models of Sjögren Syndrome

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    Purpose: Sjögren syndrome is an autoimmune disorder that occurs almost exclusively in women and is associated with extensive inflammation in lacrimal tissue, an immune-mediated destruction and/or dysfunction of glandular epithelial cells, and a significant decrease in aqueous tear secretion. We discovered that androgens suppress the inflammation in, and enhance the function of, lacrimal glands in female mouse models (e.g., MRL/MpJ-Tnfrsf6lpr [MRL/lpr]) of Sjögren syndrome. In contrast, others have reported that androgens induce an anomalous immunopathology in lacrimal glands of nonobese diabetic/LtJ (NOD) mice. We tested our hypothesis that these hormone actions reflect unique, strain- and tissue-specific effects, which involve significant changes in the expression of immune-related glandular genes. Methods: Lacrimal glands were obtained from age-matched, adult, female MRL/lpr and NOD mice after treatment with vehicle or testosterone for up to 3 weeks. Tissues were processed for analysis of differentially expressed mRNAs using CodeLink Bioarrays and Affymetrix GeneChips. Data were analyzed with bioinformatics and statistical software. Results: Testosterone significantly influenced the expression of numerous immune-related genes, ontologies, and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways in lacrimal glands of MRL/lpr and NOD mice. The nature of this hormone-induced immune response was dependent upon the autoimmune strain, and was not duplicated within lacrimal tissues of nonautoimmune BALB/c mice. The majority of immune-response genes regulated by testosterone were of the inflammatory type. Conclusions: Our findings support our hypothesis and indicate a major role for the lacrimal gland microenvironment in mediating androgen effects on immune gene expression

    Visual statistical learning and integration of perceptual priors are intact in attention deficit hyperactivity disorder

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    BackgroundDeficits in visual statistical learning and predictive processing could in principle explain the key characteristics of inattention and distractibility in attention deficit hyperactivity disorder (ADHD). Specifically, from a Bayesian perspective, ADHD may be associated with flatter likelihoods (increased sensory processing noise), and/or difficulties in generating or using predictions. To our knowledge, such hypotheses have never been directly tested.MethodsWe here test these hypotheses by evaluating whether adults diagnosed with ADHD (n = 17) differed from a control group (n = 30) in implicitly learning and using low-level perceptual priors to guide sensory processing. We used a visual statistical learning task in which participants had to estimate the direction of a cloud of coherently moving dots. Unbeknown to the participants, two of the directions were more frequently presented than the others, creating an implicit bias (prior) towards those directions. This task had previously revealed differences in other neurodevelopmental disorders, such as autistic spectrum disorder and schizophrenia.ResultsWe found that both groups acquired the prior expectation for the most frequent directions and that these expectations substantially influenced task performance. Overall, there were no group differences in how much the priors influenced performance. However, subtle group differences were found in the influence of the prior over time.ConclusionOur findings suggest that the symptoms of inattention and hyperactivity in ADHD do not stem from broad difficulties in developing and/or using low-level perceptual priors
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