708 research outputs found

    Optimizing countershading camouflage

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    Countershading, the widespread tendency of animals to be darker on the side that receives strongest illumination, has classically been explained as an adaptation for camouflage: obliterating cues to 3D shape and enhancing background matching. However, there have only been two quantitative tests of whether the patterns observed in different species match the optimal shading to obliterate 3D cues, and no tests of whether optimal countershading actually improves concealment or survival. We use a mathematical model of the light field to predict the optimal countershading for concealment that is specific to the light environment and then test this prediction with correspondingly patterned model “caterpillars” exposed to avian predation in the field. We show that the optimal countershading is strongly illumination-dependent. A relatively sharp transition in surface patterning from dark to light is only optimal under direct solar illumination; if there is diffuse illumination from cloudy skies or shade, the pattern provides no advantage over homogeneous background-matching coloration. Conversely, a smoother gradation between dark and light is optimal under cloudy skies or shade. The demonstration of these illumination-dependent effects of different countershading patterns on predation risk strongly supports the comparative evidence showing that the type of countershading varies with light environment

    Variants in KCNQ1 increase type II diabetes susceptibility in South Asians: A study of 3,310 subjects from India and the US

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    <p>Abstract</p> <p>Background</p> <p>Polymorphisms in intron 15 of potassium voltage-gated channel, KQT-like subfamily member 1 (<it>KCNQ1</it>) gene have been associated with type II diabetes (T2D) in Japanese genome-wide association studies (GWAS). More recently a meta-analysis of European GWAS has detected a new independent signal associated with T2D in intron 11 of the <it>KCNQ1 </it>gene. The purpose of this investigation is to examine the role of these variants with T2D in populations of Asian Indian descent from India and the US.</p> <p>Methods</p> <p>We examined the association between four variants in the <it>KCNQ1 </it>gene with T2D and related quantitative traits in a total of 3,310 Asian Indian participants from two different cohorts comprising 2,431 individuals of the Punjabi case-control cohort from the Sikh Diabetes Study and 879 migrant Asian Indians living in the US.</p> <p>Results</p> <p>Our data confirmed the association of a new signal at the <it>KCNQ1 </it>locus (rs231362) with T2D showing an allelic odds ratio (OR) of 1.24 95%CI [1.08-1.43], p = 0.002 in the Punjabi cohort. A moderate association with T2D was also seen for rs2237895 in the Punjabi (OR 1.14; p = 0.036) and combined cohorts (meta-analysis OR 1.14; p = 0.018). Three-site haplotype analysis of rs231362, rs2237892, rs2237895 exhibited considerably stronger evidence of association of the GCC haplotype with T2D showing OR of 1.24 95%CI [1.00-1.53], p = 0.001, permutation p = 8 × 10<sup>-4 </sup>in combined cohorts. The 'C' risk allele carriers of rs2237895 had significantly reduced measures of HOMA-B in the US cohort (p = 0.008) as well as in combined cohort in meta-analysis (p = 0.009).</p> <p>Conclusions</p> <p>Our investigation has confirmed that the variation within the <it>KCNQ1 </it>locus confers a significant risk to T2D among Asian Indians. Haplotype analysis further suggested that the T2D risk associated with <it>KCNQ1 </it>SNPs may be derived from 'G' allele of rs231362 and 'C' allele of rs2237895 and this appears to be mediated through β cell function.</p

    Relativistic Description of Exclusive Semileptonic Decays of Heavy Mesons

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    Using quasipotential approach, we have studied exclusive semileptonic decays of heavy mesons with the account of relativistic effects. Due to more complete relativistic description of the ss quark more precise expressions for semileptonic form factors are obtained. Various differential distributions in exclusive semileptonic decays of heavy mesons are calculated. It is argued that consistent account of relativistic effects and HQET motivated choice of the parameters of quark-antiquark potential allow to get reliable value for the ratio A2(0)/A1(0)A_2(0)/A_1(0) in the DKlνlD\to K^*l\nu_l decay as well as the ratio~Γ(DKlνl)/Γ(DKlνl)\Gamma(D\to K^*l\nu_l)/\Gamma(D\to Kl\nu_l). All calculated branching ratios are in accord with available experimental data.Comment: 18 pages, LATEX, 2 figures inclosed + 4 Postscript figure

    The effectiveness and cost-effectiveness of a complex community sport intervention to increase physical activity: An interrupted time series design

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    © Author(s) (or their employer(s)) 2018. Objectives: An effectiveness and cost-effectiveness analyses of two-staged community sports interventions, taster sports sessions compared with portfolio of community sport sessions. Design: Quasi-experiment using an interrupted time series design. Setting: Community sports projects delivered by eight lead partners in London Borough of Hounslow, United Kingdom Participants: Inactive people aged 14 plus years (n=246) were recruited between May 2013–February 2014. Interventions: Community sports interventions delivered in two stages, 6-week programme of taster sport sessions (Stage1) and 6-week programme of portfolio of community sporting sessions delivered by trained coaches (Stage2). Primary and secondary outcome measures: Change in days with ≥30 min of self-reported vigorous intensity physical activity (PA), moderate intensity PA, walking, sport, subjective wellbeing, and EQ5D5L quality-adjusted life-years (QALYs) Methods: Interrupted time series analysis evaluated the effectiveness of the two sports programmes. Cost-effectiveness analysis compares Stage 2 with Stage 1 from a provider’s perspective, reporting outcomes of incremental cost per Quality Adjusted Life Year (QALY) (2015/16 price year). Uncertainty was assessed using deterministic and probabilistic sensitivity analyses. Results: Compared with Stage1, counterfactual change at 21 days in PA was lower for vigorous (log odds: -0.52; 95% CI -1, -0.03), moderate PA (-0.50; CI 0.94, -0.05) and sport (-0.56; CI -1.02, -0.10). Stage 2 increased walking (0.28; CI 0.3, 0.52). Effect overtime was similar. Counterfactual change at 21 days in wellbeing was positive particularly for ‘happiness’ (0.29; CI 0.06, 0.51). Stage2 was more expensive (£101 per participant) but increased QALYs (0.001; CI -0.034, 0.036). Cost per QALY for Stage2 was £50000 and has 29% chance of being cost effective (£30000 threshold). Conclusion: Community based sport interventions could increase PA among inactive people. Less intensive sports sessions may be more effective and cost-effective

    The impact of SARS-CoV-2 on the mental health of healthcare workers in a hospital setting—A Systematic Review

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    Objectives The SARS-CoV-2 global pandemic has subjected healthcare workers (HCWs) to high risk of infection through direct workplace exposure, coupled with increased workload and psychological stress. This review aims to determine the impact of SARS-CoV-2 on mental health outcomes of hospital-based HCWs and formulate recommendations for future action. Methods A systematic review was performed between 31st December 2019 and 17th June 2020 through Ovid Medline and Embase databases (PROSPERO ID CRD42020181204). Studies were included for review if they investigated the impact of SARS-CoV-2 on mental health outcomes of hospital-based HCWs and used validated psychiatric scoring tools. Prevalence of ICD-10 classified psychiatric disorders was the primary outcome measure. Results The initial search returned 436 articles. Forty-four studies were included in final analysis, with a total of 69,499 subjects. Prevalence ranges of six mental health outcomes were identified: depression 13.5%-44.7%; anxiety 12.3%-35.6%; acute stress reaction 5.2%-32.9%; post-traumatic stress disorder 7.4%-37.4%; insomnia 33.8%-36.1%; and occupational burnout 3.1%-43.0%. Direct exposure to SARS-CoV-2 patients was the most common risk factor identified for all mental health outcomes except occupational burnout. Nurses, frontline HCWs, and HCWs with low social support and fewer years of working experience reported the worst outcomes. Conclusion The SARS-CoV-2 pandemic has significantly impacted the mental health of HCWs. Frontline staff demonstrate worse mental health outcomes. Hospitals should be staffed to meet service provision requirements and to mitigate the impact onmental health. This can be improved with access to rapid-response psychiatric teams and should be continually monitored throughout the pandemic and beyond its conclusion

    Heavy Quark Symmetry Violation in Semileptonic Decays of D Mesons

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    The decays of DD mesons to KlνK l \nu and KlνK^* l \nu final states exhibit significant deviations from the predictions of heavy-quark symmetry, as one might expect since the strange quark's mass is of the same order as the QCD scale. Nonetheless, in order to understand where the most significant effects might lie for heavier systems (such as BDlνB \to D l\nu and BDlνB \to D^* l\nu), the pattern of these deviations is analyzed from the standpoint of perturbative QCD and O(1/ms){\cal O}(1/m_s) corrections. Two main effects are noted. First, the perturbative QCD corrections lead to an overall decrease of predicted rates, which can be understood in terms of production of excited kaonic states. Second, O(1/ms){\cal O}(1/m_s) effects tend to cancel the perturbative QCD corrections in the case of KlνKl\nu decay, while they have minimal effect in KlνK^*l\nu decay.Comment: 25 pages (LaTeX) + 7 pages of Postscript figures (included at end), EFI-92-3

    Genome-Wide Linkage Scan to Identify Loci Associated with Type 2 Diabetes and Blood Lipid Phenotypes in the Sikh Diabetes Study

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    In this investigation, we have carried out an autosomal genome-wide linkage analysis to map genes associated with type 2 diabetes (T2D) and five quantitative traits of blood lipids including total cholesterol, high-density lipoprotein (HDL) cholesterol, low-density lipoprotein (LDL) cholesterol, very low-density lipoprotein (VLDL) cholesterol, and triglycerides in a unique family-based cohort from the Sikh Diabetes Study (SDS). A total of 870 individuals (526 male/344 female) from 321 families were successfully genotyped using 398 polymorphic microsatellite markers with an average spacing of 9.26 cM on the autosomes. Results of non-parametric multipoint linkage analysis using Sall statistics (implemented in Merlin) did not reveal any chromosomal region to be significantly associated with T2D in this Sikh cohort. However, linkage analysis for lipid traits using QTL-ALL analysis revealed promising linkage signals with p≤0.005 for total cholesterol, LDL cholesterol, and HDL cholesterol at chromosomes 5p15, 9q21, 10p11, 10q21, and 22q13. The most significant signal (p = 0.0011) occurred at 10q21.2 for HDL cholesterol. We also observed linkage signals for total cholesterol at 22q13.32 (p = 0.0016) and 5p15.33 (p = 0.0031) and for LDL cholesterol at 10p11.23 (p = 0.0045). Interestingly, some of linkage regions identified in this Sikh population coincide with plausible candidate genes reported in recent genome-wide association and meta-analysis studies for lipid traits. Our study provides the first evidence of linkage for loci associated with quantitative lipid traits at four chromosomal regions in this Asian Indian population from Punjab. More detailed examination of these regions with more informative genotyping, sequencing, and functional studies should lead to rapid detection of novel targets of therapeutic importance

    P and CP violation in B physics

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    While the Kobayashi--Maskawa single phase origin of CP violation passed its first crucial precision test in BJ/ψKSB\to J/\psi K_S, the chirality of weak bb-quark couplings has not yet been carefully tested. We discuss recent proposals for studying the chiral and CP-violating structure of these couplings in radiative and in hadronic B decays.Comment: 15 pages, talk at PASCOS'03, Tata Inst., Mumbai, Jan. 200
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