10,980 research outputs found

    Body size but not warning signal luminance influences predation risk in recently metamorphosed poison frogs.

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    This is the final version of the article. Available from Wiley via the DOI in this record.During early development, many aposematic species have bright and conspicuous warning appearance, but have yet to acquire chemical defenses, a phenotypic state which presumably makes them vulnerable to predation. Body size and signal luminance in particular are known to be sensitive to variation in early nutrition. However, the relative importance of these traits as determinants of predation risk in juveniles is not known. To address this question, we utilized computer-assisted design (CAD) and information on putative predator visual sensitivities to produce artificial models of postmetamorphic froglets that varied in terms of body size and signal luminance. We then deployed the artificial models in the field and measured rates of attack by birds and unknown predators. Our results indicate that body size was a significant predictor of artificial prey survival. Rates of attack by bird predators were significantly higher on smaller models. However, predation by birds did not differ between artificial models of varying signal luminance. This suggests that at the completion of metamorphosis, smaller froglets may be at a selective disadvantage, potentially because predators can discern they have relatively low levels of chemical defense compared to larger froglets. There is likely to be a premium on efficient foraging, giving rise to rapid growth and the acquisition of toxins from dietary sources in juvenile poison frogs.This study was supported by a PhD scholarship (IFARHU-SENACYT program) and a research grant No. APY-NI-010-006B/ SENACYT both awarded to EEF by the Government of Panama, and by a Royal Society University Research Fellowship to JDB. MS was supported by a Biotechnology and Biological Sciences Research Council David Phillips Research Fellowship (BB/G022887/1). HMR was supported by a Junior Research Fellowship from Churchill College, Cambridge. Special thanks to Rachel Page at STRI for supporting EEF with the grant application, Sistema Nacional de Investigacion de Panama (SNI), and the People of Santa Fe for their collaboration during the stud

    Building a Child Welfare Response to Child Trafficking Handbook (2011)

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    In 2007, the International Organization for Adolescents (IOFA), under the leadership of Katherine Kaufka Walts the then Executive Director, developed and launched the Building Child Welfare Response to Child Trafficking project. The purpose of this project is to build the capacity of child welfare agencies and service providers to identify and respond to this often invisible and underserved population. The primary goals are to ensure that children are correctly identified as trafficked persons and that they receive the appropriate protections and referrals to specialized services to which they are entitled under federal and state laws. This project, supported by funding from the Chicago Community Trust, takes place over a two year period ending in mid-2011. IOFA identified the Illinois Department of Children and Family Services (IDCFS) in Illinois as the first implementing partner for the project. IDCFS is one of the largest state government child welfare agencies in United States; it addresses the needs of thousands of children and youth every day. IOFA and IDCFS worked together to develop innovative and sustainable training and advocacy efforts on child trafficking for the child protection units within the agency. The project was designed to increase identification of cases, ensure that child trafficking victims receive full access to the legal and human rights afforded to them under the law, and ultimately to prevent further child trafficking. The project team focused on enabling child protection staff to identify and access key protections and services for victims, including special visas for undocumented victims, public benefits, job training programs, foster care, assistance in the criminal justice system, and mandatory restitution offered under the Trafficking Victims Protection Act (2000) and applicable state laws. The Building Child Welfare Response to Child Trafficking project in Illinois is a comprehensive effort, and IOFA and IDCFS continue to collaborate on additional activities in the second year of the project

    Topological quantum field theory and four-manifolds

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    I review some recent results on four-manifold invariants which have been obtained in the context of topological quantum field theory. I focus on three different aspects: (a) the computation of correlation functions, which give explicit results for the Donaldson invariants of non-simply connected manifolds, and for generalizations of these invariants to the gauge group SU(N); (b) compactifications to lower dimensions, and relations with three-manifold topology and with intersection theory on the moduli space of flat connections on Riemann surfaces; (c) four-dimensional theories with critical behavior, which give some remarkable constraints on Seiberg-Witten invariants and new results on the geography of four-manifolds.Comment: 10 pages, LaTeX. Talk given at the 3rd ECM, Barcelona, July 2000; references adde

    Community responses to seawater warming are conserved across diverse biological groupings and taxonomic resolutions

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    Temperature variability is a major driver of ecological pattern, with recent changes in average and extreme temperatures having significant impacts on populations, communities and ecosystems. In the marine realm, very few experiments have manipulated temperature in situ, and current understanding of temperature effects on community dynamics is limited. We developed new technology for precise seawater temperature control to examine warming effects on communities of bacteria, microbial eukaryotes (protists) and metazoans. Despite highly contrasting phylogenies, size spectra and diversity levels, the three community types responded similarly to seawater warming treatments of +3°C and +5°C, highlighting the critical and overarching importance of temperature in structuring communities. Temperature effects were detectable at coarse taxonomic resolutions and many taxa responded positively to warming, leading to increased abundances at the community-level. Novel field-based experimental approaches are essential to improve mechanistic understanding of how ocean warming will alter the structure and functioning of diverse marine communities

    Antibiotic use among future health professionals: A multicentre cross sectional study of Chinese medical student

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    Background: Antibiotic use leads to antibiotic resistance and antibiotic misuse is high in China and other developing countries. This may arise from beliefs and behaviours of doctors and the pressure they receive from patients. This study aims to understand antibiotic use behaviour for self-limited illness among medical students - the future healthcare professionals. Methods: This is part of a large cross-sectional study of Chinese university students of science, social science and humanities, and medicine. An electronic survey health belief model (HBM) questionnaire was distributed at six universities in China from September to November 2015. The score assessment was based on the constructs of HBM theory. Chi-squared and multivariable logistic regression and adjusted odd ratios (aOR) were used to assess the relationship between demographic characteristics, antibiotic use knowledge and behaviour. Results: In total, 11455 students were asked to participate and 11192 (97.5%) completed the questionnaires. 1819 medical students completed the survey. In the past month 529 (29%) medical students reported at least one self-limited illness. Of those, 285 (54%) self-medicated and 77 (27%) of them used antibiotics. 111 (21%) saw a doctor among whom 64 (58%) received antibiotics. 133 (25%) did nothing. In the past year, 279 (15%) of students used antibiotics for prophylaxis, 273 (15%) ever demanded an antibiotic from a doctor, 1166 (64%) kept a personal stock of antibiotics, 1034 (57%) bought antibiotics at a pharmacy, 97% of these without a prescription. Students with high HBM scores about antibiotics were significantly less likely to self-medicate with antibiotics (aOR 0.37, 95% CI 0.15-0.91, p=0.031), to use antibiotics for prophylaxis (aOR 0.35, 95% CI 0.21-0.60, p<0.0001) or demand an antibiotic (aOR 0.46, 95% CI 0.26-0.81, p=0.007). Students whose father has a higher education level, whose mother is a doctor or who are from urban areas were more likely to stock antibiotics and self-medicate. Conclusion: High rates of antibiotic self-medication (54%) and stocking (64%) were found among medical students. Along with the high rates of unnecessarily prescribed antibiotics by doctors (58%), there is clearly a need for effective antibiotic stewardship and training programs in Chinese healthcare institutions and medical schools.published_or_final_versio

    Loss of Endometrial Plasticity in Recurrent Pregnancy Loss

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    © 2015 AlphaMed Press.Menstruation drives cyclic activation of endometrial progenitor cells, tissue regeneration, and maturation of stromal cells, which differentiate into specialized decidual cells prior to and during pregnancy. Aberrant responsiveness of human endometrial stromal cells (HESCs) to deciduogenic cues is strongly associated with recurrent pregnancy loss (RPL), suggesting a defect in cellular maturation. MeDIP-seq analysis of HESCs did not reveal gross perturbations in CpG methylation in RPL cultures, although quantitative differences were observed in or near genes that are frequently deregulated in vivo. However, RPL was associated with a marked reduction in methylation of defined CA-rich motifs located throughout the genome but enriched near telomeres. Non-CpG methylation is a hallmark of cellular multipotency. Congruently, we demonstrate that RPL is associated with a deficiency in endometrial clonogenic cell populations. Loss of epigenetic stemness features also correlated with intragenic CpG hypomethylation and reduced expression of HMGB2, coding high mobility group protein 2. We show that knockdown of this sequence-independent chromatin protein in HESCs promotes senescence and impairs decidualization, exemplified by blunted time-dependent secretome changes. Our findings indicate that stem cell deficiency and accelerated stromal senescence limit the differentiation capacity of the endometrium and predispose for pregnancy failure. Stem Cells 2016;34:346-356 Recurrent pregnancy loss is caused by endometrial stem cell deficiency, triggering heightened tissue senescence and impaired decidualization

    A Systematic Review of Mosquito Coils and Passive Emanators: Defining Recommendations for Spatial Repellency Testing Methodologies.

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    Mosquito coils, vaporizer mats and emanators confer protection against mosquito bites through the spatial action of emanated vapor or airborne pyrethroid particles. These products dominate the pest control market; therefore, it is vital to characterize mosquito responses elicited by the chemical actives and their potential for disease prevention. The aim of this review was to determine effects of mosquito coils and emanators on mosquito responses that reduce human-vector contact and to propose scientific consensus on terminologies and methodologies used for evaluation of product formats that could contain spatial chemical actives, including indoor residual spraying (IRS), long lasting insecticide treated nets (LLINs) and insecticide treated materials (ITMs). PubMed, (National Centre for Biotechnology Information (NCBI), U.S. National Library of Medicine, NIH), MEDLINE, LILAC, Cochrane library, IBECS and Armed Forces Pest Management Board Literature Retrieval System search engines were used to identify studies of pyrethroid based coils and emanators with key-words "Mosquito coils" "Mosquito emanators" and "Spatial repellents". It was concluded that there is need to improve statistical reporting of studies, and reach consensus in the methodologies and terminologies used through standardized testing guidelines. Despite differing evaluation methodologies, data showed that coils and emanators induce mortality, deterrence, repellency as well as reduce the ability of mosquitoes to feed on humans. Available data on efficacy outdoors, dose-response relationships and effective distance of coils and emanators is inadequate for developing a target product profile (TPP), which will be required for such chemicals before optimized implementation can occur for maximum benefits in disease control

    A broad distribution of the alternative oxidase in microsporidian parasites

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    Microsporidia are a group of obligate intracellular parasitic eukaryotes that were considered to be amitochondriate until the recent discovery of highly reduced mitochondrial organelles called mitosomes. Analysis of the complete genome of Encephalitozoon cuniculi revealed a highly reduced set of proteins in the organelle, mostly related to the assembly of ironsulphur clusters. Oxidative phosphorylation and the Krebs cycle proteins were absent, in keeping with the notion that the microsporidia and their mitosomes are anaerobic, as is the case for other mitosome bearing eukaryotes, such as Giardia. Here we provide evidence opening the possibility that mitosomes in a number of microsporidian lineages are not completely anaerobic. Specifically, we have identified and characterized a gene encoding the alternative oxidase (AOX), a typically mitochondrial terminal oxidase in eukaryotes, in the genomes of several distantly related microsporidian species, even though this gene is absent from the complete genome of E. cuniculi. In order to confirm that these genes encode functional proteins, AOX genes from both A. locustae and T. hominis were over-expressed in E. coli and AOX activity measured spectrophotometrically using ubiquinol-1 (UQ-1) as substrate. Both A. locustae and T. hominis AOX proteins reduced UQ-1 in a cyanide and antimycin-resistant manner that was sensitive to ascofuranone, a potent inhibitor of the trypanosomal AOX. The physiological role of AOX microsporidia may be to reoxidise reducing equivalents produced by glycolysis, in a manner comparable to that observed in trypanosome
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