637 research outputs found

    The Inconsistent Work of Web Filters: Mapping Information Access in Alabama Public Schools and Libraries

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    Recent popular and academic discussions regarding the Internet have raised the question of whether and how networked intermediaries have a (dis)integrating social effects. In this study, we use public records of configurations of Internet filters in Alabama public schools and libraries to show how different institutions implement nominally consistent content standards inconsistently. We argue that these varying implementations are both significant and troubling for two reasons: first, they overreach the stated goals of the legislation with whic h they in principle comply; second, they may contribute to a broader epis temic breakdown by fragmenting the kind of information made available through and across public institutions. Keywords: Internet filtering, filter bubble, censorship, critical infrastructure studies, algorithms, categories, CIPA, libraries, schools, Leigh Sta

    Effects of Interventions Addressing School Environments or Educational Assets on Adolescent Sexual Health: Systematic Review and Meta-analysis.

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    CONTEXT: School-based interventions that aim to modify sexual health knowledge, attitudes and behaviors have mixed and often unsustained effects on adolescent sexual health outcomes. However, observational evidence suggests that broader school-related factors, such as school climate and academic attainment, can influence outcomes. METHODS: Nine databases were searched in July 2017 for randomized and quasi-experimental evaluations of interventions addressing school-level environment or student-level educational assets, to examine whether such interventions can promote young people's sexual health. Searches were limited to studies published since 1990 but were not restricted by language. Studies were assessed for risk of bias and synthesized narratively and meta-analytically. RESULTS: Searches yielded 11 evaluations, published from 1999 to 2016, of interventions related to school-level environment or student-level educational assets. Because of inconsistent reporting, the risk of bias was not clear for most studies, and meta-analysis was possible for only one outcome. The meta-analysis of three randomized trials provided some evidence that school-environment interventions may delay sexual debut (pooled odds ratio, 0.5). Narrative synthesis of the remaining outcomes found mixed results, but suggests that interventions addressing school-level environment may delay sexual debut and that those addressing student-level educational assets may reduce risk of pregnancy and STDs. CONCLUSIONS: Additional and more rigorous evidence is needed to assess the probability that interventions addressing school-related factors are effective and to provide better understanding of the mechanisms by which they may work to improve adolescent sexual health

    Dynamic detection of electron spin accumulation in ferromagnet-semiconductor devices by ferromagnetic resonance

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    A distinguishing feature of spin accumulation in ferromagnet-semiconductor devices is precession of the non-equilibrium spin population of the semiconductor in a magnetic field. This is the basis for detection techniques such as the Hanle effect, but these approaches become less effective as the spin lifetime in the semiconductor decreases. For this reason, no electrical Hanle measurement has been demonstrated in GaAs at room temperature. We show here that by forcing the magnetization in the ferromagnet (the spin injector and detector) to precess at the ferromagnetic resonance frequency, an electrically generated spin accumulation can be detected from 30 to 300 K. At low temperatures, the distinct Larmor precession of the spin accumulation in the semiconductor can be detected by ferromagnetic resonance in an oblique field. We verify the effectiveness of this new spin detection technique by comparing the injection bias and temperature dependence of the measured spin signal to the results obtained using traditional methods. We further show that this new approach enables a measurement of short spin lifetimes (< 100 psec), a regime that is not accessible in semiconductors using traditional Hanle techniques.Comment: 4 figure

    School experiences and young women's pregnancy and parenthood decisions: A systematic review and synthesis of qualitative research.

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    Schools are considered high-potential environments for promoting adolescent sexual and reproductive health outcomes among young women. Qualitative studies provide context and meaning to how school experiences and systems contribute to pregnancy and parenthood decisions from the perspectives of youth. This systematic review screened 24,711 references from 8 databases, yielding 28 qualitative studies. Included studies were assessed for quality and synthesised using meta-ethnographic approaches. Reciprocal translation revealed that young women's education and life trajectories were at least partially shaped by a commitment to school values and expectations for academic achievement, influenced by structural and relational factors within the school. These findings resonate with Markham and Aveyard's theory of human functioning and school organisation. Future policy and practices might seek to improve teacher-student interactions, leverage young women's developing autonomy, and ensure physically and psychologically safe spaces for students

    Sawflies (Hymenoptera, Symphyta) Newly Recorded from Washington State

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    Examination of museum specimens, unpublished collection data, and field surveys conducted between 2010 and 2014 resulted in records for 22 species of sawflies new to Washington State, seven of which are likely to be pest problems in ornamental landscapes. These data highlight the continued range expansion of exotic species across North America. These new records also indicate that our collective knowledge of Pacific Northwest arthropod biodiversity and biogeography is underdeveloped, even for a relatively well known and species-poor group of insects. Notable gaps in the knowledge of Washington State’s Symphyta remain for the Olympic Peninsula, the Cascade Mountain Range, and the arid interior of the state. Washington’s shrub-steppe appears to be particularly poorly surveyed for sawflies

    Sawflies (Hymenoptera, Symphyta) Newly Recorded from Washington State

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    Examination of museum specimens, unpublished collection data, and field surveys conducted between 2010 and 2014 resulted in records for 22 species of sawflies new to Washington State, seven of which are likely to be pest problems in ornamental landscapes. These data highlight the continued range expansion of exotic species across North America. These new records also indicate that our collective knowledge of Pacific Northwest arthropod biodiversity and biogeography is underdeveloped, even for a relatively well known and species-poor group of insects. Notable gaps in the knowledge of Washington State’s Symphyta remain for the Olympic Peninsula, the Cascade Mountain Range, and the arid interior of the state. Washington’s shrub-steppe appears to be particularly poorly surveyed for sawflies

    Sheep Updates 2003 - Wool

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    This session covers six papers from different authors:1.‘Pastures from space’ - an opportunity to increase the profitability of sheep production Richard Coole Farmer Kojonup W.A. Stephen Gherardi Chris Oldham Department of Agriculture Western Australia 2. K. Curtis Department of Agriculture WA J. Stanton Department of Agriculture WA and Curtin University 3. Is selection of ewe hogget replacement on measurement profitable? Johan Greeff Department of Agriculture of Western Australia 4. Optimising the nutrition/grazing management of ewe flocks Chris Oldham Mike Hyder Beth Paganoni Department of Agriculture of Western Australia Andrew Thompson Department of Primary Industries, Hamilton, Victoria Tom Plaisted Kazue Tanaka Department of Agriculture of Western Australia Mark Ferguson Darren Gordon Department of Primary Industries, Hamilton, Victoria 5. How do we produce wool for next-to-skin wear? Andrew Peterson Department of Agriculture Western Australia 6. Measuring fibre contamination post farm gate Peter Sommerville Corporate Development Manager AWTA Lt

    Phylogeny, Genome Size, and Chromosome Evolution of Asparagales

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    Asparagales are a diverse monophyletic order that has numerous species (ca. 50% of monocots) including important crop plants such as Allium, Asparagus, and Vanilla, and a host of ornamentals such as irises, hyacinths, and orchids. Historically, Asparagales have been of interest partly because of their fascinating chromosomal evolution. We examine the evolutionary dynamics of Asparagales genomes in an updated phylogenetic framework that combines analyses of seven gene regions (atp1, atpB, matK, ndhF, rbcL, trnL intron, and trnL-F intergenic spacer) for 79 taxa of Asparagales and outgroups. Asparagales genomes are evolutionarily labile for many characters, including chromosome number and genome size. The history and causes of variation in chromosome number and genome size remain unclear, primarily because of the lack of data in small clades in the phylogenetic tree and the lack of comparative genetic maps, apart from Allium and Asparagus. Genomic tools such as bacterial artificial chromosome (BAC) libraries should be developed, as both molecular cytogenetic markers and a source of nuclear genes that can be widely used by evolutionary biologists and plant breeders alike to decipher mechanisms of chromosomal evolution
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