16,778 research outputs found

    Three dimensional dynamical and chemical modelling of the upper atmosphere

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    Improved versions of a global 3-dimensional dynamical-chemical model of the stratospheric ozone layer were developed and utilized. The major accomplishments are described

    Eliminating Racial/Ethnic Health Disparities: Reconsidering Comparative Approaches

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    The focus on eliminating racial/ethnic health disparities has brought critical attention to the poor health status of minority populations. Assessing the health outcomes of racial minority groups by comparing them to a racial majority standard is valuable for identifying and monitoring health inequities, but may not be the most effective approach to identifying strategies that can be used to improve minority health outcomes. Health promotion planning models and public health history both suggest that minority health promotion is more likely to be derived from interventions rooted in culturally and historically grounded contextual factors. In this essay, we highlight limitations of comparative approaches to minority health research and argue that integrating emic (or within-group) approaches may facilitate research and interventions more consonant with national goals to promote health and reduce disparities than comparative approaches

    The myths and realities of Bayesian chronological modeling revealed

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    We review the history of Bayesian chronological modeling in archaeology and demonstrate that there has been a surge over the past several years in American archaeological applications. Most of these applications have been performed by archaeologists who are self-taught in this method because formal training opportunities in Bayesian chronological modeling are infrequently provided. We define and address misconceptions about Bayesian chronological modeling that we have encountered in conversations with colleagues and in anonymous reviews, some of which have been expressed in the published literature. Objectivity and scientific rigor is inherent in the Bayesian chronological modeling process. Each stage of this process is described in detail, and we present examples of this process in practice. Our concluding discussion focuses on the potential that Bayesian chronological modeling has for enhancing understandings of important topics

    A Comparison of Two Methods of Quantifying Mating Success in Low Density Gypsy Moth (Lymantria dispar) Populations

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    The gypsy moth (Lymantria dispar) is a defoliating pest native to Europe and invasive to North America. The gypsy moth is subject to depressed mating success in low density populations, which may restrict spread of the forest pest. Research focusing on gypsy moth density as it relates to mating behavior has often used counts of males caught in pheromone-baited delta traps as a proxy to estimate the probability of female mating success. The purpose of this project was to determine whether pheromone trap counts provide accurate estimates of female mating success probability, by comparing data gathered from pheromone-baited delta traps to data gathered on mating success of tethered females. To determine the relationship between number of males caught in delta traps and the probability of successful mating, male catch counts in traps were compared to mating success of tethered females in a mass male release experiment. The relationship between delta trap catch of males and female mating success was quantified using a Bayesian framework, which explicitly incorporates uncertainties in the model. Vegetative cover in the study plots was reduced to a single measure through principal components analysis and included as an independent factor in the model. The data suggest that delta traps reduce the male’s ability to find a female by 67%; thus, results garnered from delta trap catch counts tend to underestimate the underlying ability of males to locate and mate with females. Thick understory vegetation further reduced the male’s ability to locate a female, and further reduced the effectiveness of delta traps. Future studies that seek to use counts of males in pheromone-baited traps as a proxy for mating success should consider using an adjustment factor to equate the two methods of quantifying reproductive behavior in the gypsy moth.https://scholarscompass.vcu.edu/uresposters/1271/thumbnail.jp

    Individually mark–mass release–resight study elucidates effects of patch characteristics and distance on host patch location by an insect herbivore

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    1. How organisms locate their hosts is of fundamental importance in a variety of basic and applied ecological fields, including population dynamics, invasive species management and biological control. However, tracking movement of small organisms, such as insects, poses significant logistical challenges. 2. Mass-release and individual–mark–recapture techniques were combined in an individually mark–mass release–resight (IMMRR) approach to track the movement of over 2000 adult insects in an economically important plant–herbivore system. Despite its widespread use for the biological control of the invasive thistle Carduus nutans, the host-finding behaviour of the thistle head weevil Rhinocyllus conicus has not previously been studied. Insects were released at different distances from a mosaic of artificially created host patches with different areas and number of plants to assess the ecological determinants of patch finding. 3. The study was able to characterize the within-season dispersal abilities and between-patch movement patterns of R. conicus. Weevils found host plant patches over 900 m away. Large patches, with tall plants, situated close to the nearest release point had the highest first R. conicusresights. Patch area and plant density had no effect on the number of weevils resighted per plant; however, R. conicus individuals were more likely to disperse out of small patches and into large patches. 4. By understanding how R. conicus locates host patches of C. nutans, management activities for the control of this invasive thistle can be better informed. A deeper mechanistic understanding of host location will also improve prediction of coupled plant–herbivore spatial dynamics in general

    Social optimality in quantum Bayesian games

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    A significant aspect of the study of quantum strategies is the exploration of the game-theoretic solution concept of the Nash equilibrium in relation to the quantization of a game. Pareto optimality is a refinement on the set of Nash equilibria. A refinement on the set of Pareto optimal outcomes is known as social optimality in which the sum of players' payoffs are maximized. This paper analyzes social optimality in a Bayesian game that uses the setting of generalized Einstein-Podolsky-Rosen experiments for its physical implementation. We show that for the quantum Bayesian game a direct connection appears between the violation of Bell's inequality and the social optimal outcome of the game and that it attains a superior socially optimal outcome.Comment: 12 pages, revise
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