677 research outputs found

    Where the Deer and The Antelope Play:Conserving Big Game Migrations As an Endangered Phenomena

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    In the American West, high-profile big game species including mule deer, antelope, elk, moose, bison and bighorn sheep use large landscapes to migrate between winter and summer habitats to obtain the resources they need to survive. The big game species are a vital part of the West’s ecology, economy, and culture and are valued by local, national, and international stakeholders. Thanks to large parcels of private and public land and a low human population, many parts of the American West still provide some of the best big game habitats in the world. But these vast, intact landscapes are under threat by ongoing habitat loss and disturbances to seasonal and migratory habitats that result in declines in big game population and the disappearance of migrations. Addressing the challenge of conserving big game populations and the endangered phenomena of seasonal migration across large landscapes in the American West will require dynamic, innovative, and flexible legal approaches. Those legal approaches should recognize the biological needs of the species themselves and reflect economic policy analysis of conservation in landscapes with multiple land managers. Considering both integrated biological and economic decision frameworks and incentive-based tools to define and implement legal and policy structures can produce migratory species conservation more efficiently than less integrated approaches. Conservation of big game migrations is now a growing priority and initial conservation efforts are beginning to emerge, including the Department of Interior Secretarial Order 3362 “Improving Habitat Quality in Western Big-Game Winter Range and Migration Corridors” and state policies including the Wyoming Game and Fish Department Ungulate Migration Corridor Strategy. This interdisciplinary paper evaluates those emerging policies and finds that the policies miss opportunities to provide higher levels of conservation of migratory species by failing to address key ecological characteristics of migratory species and to incorporate economically efficient hierarchies of management and policy. We conclude by offering thoughts on how future conservation polices might be designed to incorporate both ecology and economics to better conserve migrations

    Perfluorooctanoic Acid–Induced Immunomodulation in Adult C57BL/6J or C57BL/6N Female Mice

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    BackgroundPerfluorooctanoic acid (PFOA), an environmentally persistent compound of regulatory concern, has been reported to reduce antibody responses in mice at a single dose.ObjectiveThe aim of this study was to evaluate PFOA effects on humoral and cellular immunity using standard assays for assessing immune function, and to derive dose–response data.MethodsC57BL/6J mice received 0 or 30 mg PFOA/kg/day for 10 days; half of the exposed groups were switched to vehicle and half continued on PFOA for five days. C57BL/6N mice received 0–30 mg/kg/day of PFOA in drinking water for 15 days. Mice were immunized with sheep red blood cells or sensitized to bovine serum albumin in Freund’s complete adjuvant on day 10 of exposure; immune responses were determined 1 day post-exposure.ResultsWe found that 30 mg PFOA/kg/day given for 10 or 15 days reduced IgM synthesis; serum collected 1 day postexposure contained 8.4 × 104 or 2.7 × 105 ng PFOA/mL, respectively. IgM synthesis was suppressed at exposures ≥ 3.75 mg PFOA/kg/day in a dose-dependent manner, and IgG titers were elevated at 3.75 and 7.5 mg PFOA/kg/day. Serum PFOA at 3.75 mg/kg/day was 7.4 × 104 ng/mL 1 day postexposure, or 150-fold greater than the levels reported in individuals living near a PFOA production site. Using a second-degree polynomial model, we calculated a benchmark dose of 3 mg/kg/day, with a lower bound (95% confidence limit) of 1.75 mg/kg/day. Cell-mediated function was not affected.ConclusionsIgM antibodies were suppressed after PFOA exposure. The margin of exposure for reduced IgM antibody synthesis was approximately 150 for highly exposed human populations

    Assessing the Need and Receptivity for an Integrated Healthy Sexual and Dating Relationships Intervention for Community College Students

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    Background: In emerging adulthood, youth often become involved in more serious romantic relationships. However, many lack the skills to avoid an unplanned pregnancy or sexually transmitted infection (STI), and to ensure a healthy dating relationship. Community college students serve nearly half of all undergraduate students in the United States; yet, community colleges typically lack resources for sexual health promotion. Purpose: To assess the need and receptivity for a web-based integrated healthy sexual and dating relationships intervention among community college students. Methods: In summer 2016, we partnered with three community colleges in South Central Texas to conduct an online survey of students’ sexual behaviors and dating relationships, and usability testing of activities from an integrated, web-based healthy sexual and dating relationship intervention. Results: Online survey participants (n=271) were 70% female, 38% Hispanic, 24% White, 17% Black, and 16% Asian; 20% self-identified as sexual minority; mean age was 20.8 years (SD = 2.05). Participants reported high rates of sexual risk behavior including sex without a condom or an effective birth control method, low use of long-acting reversible contraception, frequent use of emergency contraception, and low use of dual protection to prevent pregnancy and sexually transmitted infections. Two-thirds reported experiencing any type of dating violence perpetration or victimization in the past year. Usability testing participants (n=14) were 86% female, 42% Hispanic, 50% Asian/Pacific Islander, 14% Black, and 7% White; 71% were sexually experienced; mean age was 20.7 years (SD = 1.64). The web-based activities were highly rated in terms of usability parameters, and positively impacted short-term psychosocial outcomes related to condom use, accessing contraceptive health services, and constructive interpersonal conflict resolution. Conclusion: Findings underscore the high need and receptivity for an integrated healthy sexual and dating relationship web-based intervention among community college students, an understudied subgroup of youth in emerging adulthood

    The Lieb-Liniger Model as a Limit of Dilute Bosons in Three Dimensions

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    We show that the Lieb-Liniger model for one-dimensional bosons with repulsive δ\delta-function interaction can be rigorously derived via a scaling limit from a dilute three-dimensional Bose gas with arbitrary repulsive interaction potential of finite scattering length. For this purpose, we prove bounds on both the eigenvalues and corresponding eigenfunctions of three-dimensional bosons in strongly elongated traps and relate them to the corresponding quantities in the Lieb-Liniger model. In particular, if both the scattering length aa and the radius rr of the cylindrical trap go to zero, the Lieb-Liniger model with coupling constant ga/r2g \sim a/r^2 is derived. Our bounds are uniform in gg in the whole parameter range 0g0\leq g\leq \infty, and apply to the Hamiltonian for three-dimensional bosons in a spectral window of size r2\sim r^{-2} above the ground state energy.Comment: LaTeX2e, 19 page

    Distinct self-interaction domains promote Multi Sex Combs accumulation in and formation of the Drosophila histone locus body

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    Nuclear bodies (NBs) are structures that concentrate proteins, RNAs, and ribonucleoproteins that perform functions essential to gene expression. How NBs assemble is not well understood. We studied the Drosophila histone locus body (HLB), a NB that concentrates factors required for histone mRNA biosynthesis at the replication-dependent histone gene locus. We coupled biochemical analysis with confocal imaging of both fixed and live tissues to demonstrate that the Drosophila Multi Sex Combs (Mxc) protein contains multiple domains necessary for HLB assembly. An important feature of this assembly process is the self-interaction of Mxc via two conserved N-terminal domains: a LisH domain and a novel self-interaction facilitator (SIF) domain immediately downstream of the LisH domain. Molecular modeling suggests that the LisH and SIF domains directly interact, and mutation of either the LisH or the SIF domain severely impairs Mxc function in vivo, resulting in reduced histone mRNA accumulation. A region of Mxc between amino acids 721 and 1481 is also necessary for HLB assembly independent of the LisH and SIF domains. Finally, the C-terminal 195 amino acids of Mxc are required for recruiting FLASH, an essential histone mRNA-processing factor, to the HLB. We conclude that multiple domains of the Mxc protein promote HLB assembly in order to concentrate factors required for histone mRNA biosynthesis
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