1,227 research outputs found

    Evaluation of a ln tan integral arising in quantum field theory

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    We analytically evaluate a dilogarithmic integral that is prototypical of volumes of ideal tetrahedra in hyperbolic geometry. We additionally obtain new representations of the Clausen function Cl_2 and the Catalan constant G=Cl_2(\pi/2), as well as new relations between sine and Clausen function values.Comment: 24 pages, no figure

    Rapid parallel adaptation despite gene flow in silent crickets

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    The work was funded by Natural Environment Research Council awards to N.W.B. [NE/I027800/1, NE/L011255/1]. Bioinformatics support was provided by a Wellcome Trust ISSF award [105621/Z/14/Z]. X.Z. was supported by a China Scholarship Council PhD studentship [201703780018].Gene flow is predicted to impede parallel adaptation via de novo mutation, because it can introduce pre-existing adaptive alleles from population to population. We test this using Hawaiian crickets (Teleogryllus oceanicus) in which ‘flatwing’ males that lack sound-producing wing structures recently arose and spread under selection from an acoustically-orienting parasitoid. Morphometric and genetic comparisons identify distinct flatwing phenotypes in populations on three islands, localized to different loci. Nevertheless, we detect strong, recent and ongoing gene flow among the populations. Using genome scans and gene expression analysis we find that parallel evolution of flatwing on different islands is associated with shared genomic hotspots of adaptation that contain the gene doublesex, but the form of selection differs among islands and corresponds to known flatwing demographics in the wild. We thus show how parallel adaptation can occur on contemporary timescales despite gene flow, indicating that it could be less constrained than previously appreciated.Publisher PDFPeer reviewe

    Development of stable reporter system cloning luxCDABE genes into chromosome of Salmonella enterica serotypes using Tn7 transposon

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    <p>Abstract</p> <p>Background</p> <p>Salmonellosis may be a food safety problem when raw food products are mishandled and not fully cooked. In previous work, we developed bioluminescent <it>Salmonella enterica </it>serotypes using a plasmid-based reporting system that can be used for real-time monitoring of the pathogen's growth on food products in short term studies. In this study, we report the use of a Tn7-based transposon system for subcloning of <it>luxCDABE </it>genes into the chromosome of eleven <it>Salmonella enterica </it>serotypes isolated from the broiler production continuum.</p> <p>Results</p> <p>We found that the <it>lux </it>operon is constitutively expressed from the chromosome post-transposition and the <it>lux </it>cassette is stable without external pressure, i.e. antibiotic selection, for all <it>Salmonella enterica </it>serotypes used. Bioluminescence expression is based on an active electron transport chain and is directly related with metabolic activity. This relationship was quantified by measuring bioluminescence against a temperature gradient in aqueous solution using a luminometer. In addition, bioluminescent monitoring of two serotypes confirmed that our chicken skin model has the potential to be used to evaluate pathogen mitigation strategies.</p> <p>Conclusions</p> <p>This study demonstrated that our new stable reporting system eliminates bioluminescence variation due to plasmid instability and provides a reliable real-time experimental system to study application of preventive measures for <it>Salmonella </it>on food products in real-time for both short and long term studies.</p

    Proopiomelanocortin Neurons in Nucleus Tractus Solitarius Are Activated by Visceral Afferents: Regulation by Cholecystokinin and Opioids

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    The nucleustractus solitarius (NTS) receives dense terminations from cranial visceral afferents, including those from the gastrointestinal (GI) system. Although the NTS integrates peripheral satiety signals and relays this signal to central feeding centers, little is known about which NTS neurons are involved or what mechanisms are responsible. Proopiomelanocortin (POMC) neurons are good candidates for GI integration, because disruption of the POMC gene leads to severe obesity and hyperphagia. Here, we used POMC– enhanced green fluorescent protein (EGFP) transgenic mice to identify NTS POMC neurons. Intraperitoneal administration of cholecystokinin (CCK) induced c-fos gene expression in NTS POMC–EGFP neurons, suggesting that they are activated by afferents stimulated by the satiety hormone. We tested the synaptic relationship of these neurons to visceral afferents and their modulation by CCK and opioids using patch recordings in horizontal brain slices. Electrical activation of the solitary tract (ST) evoked EPSCs in NTS POMC–EGFP neurons. The invariant latencies, low failure rates, and substantial paired-pulse depression of the ST-evoked EPSCs indicate that NTS POMC–EGFP neurons are second-order neurons directly contacted by afferent terminals. The EPSCs were blocked by the glutamate antagonist 2,3- dihydroxy-6-nitro-7-sulfonyl-benzo[f]quinoxaline. CCK increased the amplitude of the ST-stimulated EPSCs and the frequency of miniature EPSCs, effects attenuated by the CCK1 receptor antagonist lorglumide. In contrast, the orexigenic opioid agonists [D-Ala(2), N-Me-Phe(4), Gly-ol(5)]-enkephalin and met-enkephalin inhibited both ST-stimulated EPSCs and the frequency of miniature EPSCs. These findings identify a potential satiety pathway in which visceral afferents directly activate NTS POMC–EGFP neurons with excitatory inputs that are appropriately modulated by appetite regulators

    Screening Coriander Gene Pool for Special Uses

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    Coriander (Coriandrum sativum L.) is an aromatic member of the Apiaceae with a wide diversity of uses (Diederichsen 1996). Its rapid life cycle allows it to fit into different growing seasons, making it possible to grow the crop under a wide range of conditions. Three subspecies and 10 botanical varieties of coriander have been proposed at the infraspecific level (Diederichsen and Hammer 2003) based on phenotypic characteristics; however, molecular evidence does not support classifications based on phenotypic and/or biochemical characteristics (LĂłpez 2006). The objectives of our study were to assess the phenotypic and biochemical characteristics of coriander germplasm collections that would make them suitable for different uses and to use amplified fragment length polymorphism (AFLP) (Vos et al. 1995) to clarify patterns of genetic diversity and its partitioning among these populations, by means of an analysis of molecular variance (AMOVA) (Excoffier et al. 1992)

    Place attachment in deprived neighbourhoods: The impacts of population turnover and social mix

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    This paper examines the determinants of individual place attachment, focussing in particular on differences between deprived and others neighbourhoods, and on the impacts of population turnover and social mix. It uses a multi-level modelling approach to take account of both individual- and neighbourhood-level determinants. Data are drawn from a large sample government survey, the Citizenship Survey 2005, to which a variety of neighbourhood-level data have been attached. The paper argues that attachment is significantly lower in more deprived neighbourhoods primarily because these areas have weaker social cohesion but that, in other respects, the drivers of attachment are the same. Turnover has modest direct impacts on attachment through its effect on social cohesion. Social mix has very limited impacts on attachment and the effects vary between social groups. In general, higher status or more dominant groups appear less tolerant of social mix

    XMM-Newton observations of three short period polars: V347 Pav, GG Leo and EU UMa

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    We present phase-resolved XMM_Newton data of three short period polars: V347 Pav, GG Leo and EU UMa. All three systems show one dominant accretion region which is seen for approximately half of the orbital cycle. GG Leo shows a strong dip feature in its X-ray and UV light curves which is due to absorption of X-rays from the accretion site by the accretion stream. The emission in the case of EU UMa is dominated by soft X-rays: its soft/hard X-ray ratio is amongst the highest seen in these objects. In contrast, GG Leo and V347 Pav shows a ratio consistent with that predicted by the standard shock model. We infer the mass of the white dwarf and explore the affect of restricting the energy range on the derived parameters.Comment: accepted MNRA

    A simplified, combined protocol versus standard treatment for acute malnutrition in children 6-59 months (ComPAS trial): A cluster-randomized controlled non-inferiority trial in Kenya and South Sudan.

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    BACKGROUND: Malnutrition underlies 3 million child deaths worldwide. Current treatments differentiate severe acute malnutrition (SAM) from moderate acute malnutrition (MAM) with different products and programs. This differentiation is complex and costly. The Combined Protocol for Acute Malnutrition Study (ComPAS) assessed the effectiveness of a simplified, unified SAM/MAM protocol for children aged 6-59 months. Eliminating the need for separate products and protocols could improve the impact of programs by treating children more easily and cost-effectively, reaching more children globally. METHODS AND FINDINGS: A cluster-randomized non-inferiority trial compared a combined protocol against standard care in Kenya and South Sudan. Randomization was stratified by country. Combined protocol clinics treated children using 2 sachets of ready-to-use therapeutic food (RUTF) per day for those with mid-upper arm circumference (MUAC) < 11.5 cm and/or edema, and 1 sachet of RUTF per day for those with MUAC 11.5 to <12.5 cm. Standard care clinics treated SAM with weight-based RUTF rations, and MAM with ready-to-use supplementary food (RUSF). The primary outcome was nutritional recovery. Secondary outcomes included cost-effectiveness, coverage, defaulting, death, length of stay, and average daily weight and MUAC gains. Main analyses were per-protocol, with intention-to-treat analyses also conducted. The non-inferiority margin was 10%. From 8 May 2017 to 31 March 2018, 2,071 children were enrolled in 12 combined protocol clinics (mean age 17.4 months, 41% male), and 2,039 in 12 standard care clinics (mean age 16.7 months, 41% male). In total, 1,286 (62.1%) and 1,202 (59.0%), respectively, completed treatment; 981 (76.3%) on the combined protocol and 884 (73.5%) on the standard protocol recovered, yielding a risk difference of 0.03 (95% CI -0.05 to 0.10, p = 0.52; per-protocol analysis, adjusted for country, age, and sex). The amount of ready-to-use food (RUTF or RUSF) required for a child with SAM to reach full recovery was less in the combined protocol (122 versus 193 sachets), and the combined protocol cost US123lessperchildrecovered(US123 less per child recovered (US918 versus US$1,041). There were 23 (1.8%) deaths in the combined protocol arm and 21 (1.8%) deaths in the standard protocol arm (adjusted risk difference 95% CI -0.01 to 0.01, p = 0.87). There was no evidence of a difference between the protocols for any of the other secondary outcomes. Study limitations included contextual factors leading to defaulting, a combined multi-country power estimate, and operational constraints. CONCLUSIONS: Combined treatment for SAM and MAM is non-inferior to standard care. Further research should focus on operational implications, cost-effectiveness, and context (Asia versus Africa; emergency versus food-secure settings). This trial is complete and registered at ISRCTN (ISRCTN30393230). TRIAL REGISTRATION: The trial is registered at ISRCTN, trial number ISRCTN30393230
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