369 research outputs found

    Introduction to mathematical physics

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    A comprehensive survey of all the mathematical methods that should be available to graduate students in physics. In addition to the usual topics of analysis, such as infinite series, functions of a complex variable and some differential equations as well as linear vector spaces, this book includes a more extensive discussion of group theory than can be found in other current textbooks. The main feature of this textbook is its extensive treatment of geometrical methods as applied to physics. With its introduction of differentiable manifolds and a discussion of vectors and forms on such manifolds as part of a first-year graduate course in mathematical methods, the text allows students to grasp at an early stage the contemporary literature on dynamical systems, solitons and related topological solutions to field equations, gauge theories, gravitational theory, and even string theor

    Public or private religiosity: which Is protective for adolescent substance use and by what pathways?

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    While it is well understood that adolescent religiosity is associated with the use and abuse of licit and illicit substances, few studies have revealed the pathways through which religiosity buffers youth against involvement in such behavior. The aim of this study is to examine the complexity of the relationships between religiosity, sensation seeking, injunctive norms, and adolescent substance use. Using a national sample of adolescents (N = 18,614), negative binomial regression and path analysis were used to examine the various components of the relationship between religiosity and the use of cigarettes, alcohol, and marijuana. Results indicate that private religiosity moderates the relationship between key risk factors and substance use. Public and private religiosity were associated with tolerant injunctive substance use norms which, in turn, were associated with substance use. Implications for research and theory related to religiosity and adolescent substance use are discussed

    Developing Cost Effective Monitoring for Rainbow Smelt Using eDNA

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    Environmental DNA (eDNA) tools developed at the University of Maine were successfully deployed in four coastal streams in Casco Bay, Maine in spring 2018 to detect the presence of anadromous rainbow smelt (Osmerus mordax), the first full application of this emerging technique. Field methods were refined and tested at sites with documented high (2) and low (2) spawning productivity. Samples were collected below known spawning areas immediately upstream of estuarine tidal influence 2-3 times each week during the spawning season. Three replicate samples were collected in the field at each site, as well as a contamination control, and all samples were filtered and preserved for laboratory analysis. Extracted eDNA samples and controls were run on three replicate qPCR assays. Initial efforts to extract eDNA from samples were hampered by the presence of environmental inhibitors. Use of a Zymo OneStep PCR Inhibitor Removal Kits appears to have overcome this problem and field collected eDNA samples were amplified successfully using quantitative polymerase chain reaction (qPCR). In partnership with a qualified lab, these tools can now provide a low-cost, userfriendly, and reliable method for monitoring the presence of rainbow smelt

    Regularization Dependence of Running Couplings in Softly Broken Supersymmetry

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    We discuss the dependence of running couplings on the choice of regularization method in a general softly-broken N=1 supersymmetric theory. Regularization by dimensional reduction respects supersymmetry, but standard dimensional regularization does not. We find expressions for the differences between running couplings in the modified minimal subtraction schemes of these two regularization methods, to one loop order. We also find the two-loop renormalization group equations for gaugino masses in both schemes, and discuss the application of these results to the Minimal Supersymmetric Standard Model.Comment: 11 pages. v2: Signs of equations (1.2) and (4.2) are fixe

    Coding of sexual assault by emergency physicians: A nationally representative study

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    INTRODUCTION: Sexual assault is a public health problem that affects many Americans and has multiple long-lasting effects on victims. Medical evaluation after sexual assault frequently occurs in the emergency department, and documentation of the visit plays a significant role in decisions regarding prosecution and outcomes of legal cases against perpetrators. The American College of Emergency Physicians recommends coding such visits as sexual assault rather than adding modifiers such as alleged. METHODS: This study reviews factors associated with coding of visits as sexual assault compared to suspected sexual assault using the 2016 Nationwide Emergency Department Sample. RESULTS: Younger age, female gender, a larger number of procedure codes, urban hospital location, and lack of concurrent alcohol use are associated with coding for confirmed sexual assault. CONCLUSION: Implications of this coding are discussed

    Decoupling of the ϵ\epsilon-scalar mass in softly broken supersymmetry

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    It has been shown recently that the introduction of an unphysical ϵ\epsilon-scalar mass m~\tilde{m} is necessary for the proper renormalization of softly broken supersymmetric theories by dimensional reduction (\drbar). In these theories, both the two-loop β\beta-functions of the scalar masses and their one-loop finite corrections depend on m~2\tilde{m}^2. We find, however, that the dependence on m~2\tilde{m}^2 can be completely removed by slightly modifying the \drbar renormalization scheme. We also show that previous \drbar calculations of one-loop corrections in supersymmetry which ignored the m~2\tilde{m}^2 contribution correspond to using this modified scheme.Comment: 7 pages, LTH-336, NUB-3094-94TH, KEK-TH-40

    Profiles of acculturation among Hispanics in the United States: links with discrimination and substance use

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    Recent research suggests that acculturation is a multifaceted construct with implications for substance use among Hispanics. However, few, if any, studies examining profiles of acculturation have been conducted using national samples. Moreover, no cluster-based studies have examined how acculturation relates to discrimination and substance use disorders among Hispanics in the United States

    Everyday discrimination and mood and substance use disorders: A latent profile analysis with African Americans and Caribbean Blacks

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    Perceived discrimination is a major source of health-related stress. The purpose of this study was to model the heterogeneity of everyday-discrimination experiences among African American and Caribbean Blacks and to identify differences in the prevalence of mood and substance use outcomes, including generalized anxiety disorder, major depressive disorder, alcohol-use disorder, and illicit drug-use disorder among the identified subgroups. The study uses data from the National Survey of American Life obtained from a sample of African American and Caribbean Black respondents (N = 4,462) between 18 and 65 years. We used latent profile analysis and multinomial regression analyses to identify and validate latent subgroups and test hypotheses, yielding 4 classes of perceived everyday discrimination: Low Discrimination, Disrespect and Condescension, General Discrimination, and Chronic Discrimination. Findings show significant differences exist between the Low Discrimination and General Discrimination classes for major depressive disorder, alcohol-use disorder, and illicit drug-use disorder. Moreover, we find significant differences exist between the Low Discrimination and Chronic Discrimination classes for the four disorders examined. Compared with the Chronic Discrimination class, members of the other classes were significantly less likely to meet criteria for generalized anxiety disorder, major depressive disorder, alcohol-use disorder, and illicit drug-use disorder. Findings suggest elevated levels of discrimination increase risk for mood and substance-use disorders. Importantly, results suggest the prevalence of mood and substance-use disorders is a function of the type and frequency of discrimination that individuals experience

    Substance Use Disorders Among First- and Second-Generation Immigrant Adults in the United States: Evidence of an Immigrant Paradox?

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    A growing number of studies have examined the “immigrant paradox” with respect to the use of licit and illicit substances in the United States. However, there remains a need for a comprehensive examination of the multigenerational and global links between immigration and substance use disorders among adults in the United States

    Globally distributed occurrences utilised in 200 spider species conservation profiles (Arachnida, Araneae)

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    Background Data on 200 species of spiders were collected to assess the global threat status of the group worldwide. To supplement existing digital occurrence records from GBIF, a dataset of new occurrence records was compiled for all species using published literature or online sources, from which geographic coordinates were extracted or interpreted from locality description data. New information A total of 5,104 occurrence records were obtained, of which 2,378 were from literature or online sources other than GBIF. Of these, 2,308 had coordinate data. Reporting years ranged from 1834 to 2017. Most records were from North America and Europe, with Brazil, China, India and Australia also well represented.Peer reviewe
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