919 research outputs found

    Vector meson spectral function and dilepton rate in an effective mean field model

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    We have studied the vector meson spectral function (VMSF) in a hot and dense medium within an effective QCD model namely the Nambu-Jona-Lasinio (NJL) and its Polyakov Loop extended version (PNJL) with and without the effect of isoscalar vector interaction (IVI). The effect of the IVI has been taken into account using the ring approximation. We obtained the dilepton production rate (DPR) using the VMSF and observed that at moderate temperature it is enhanced in the PNJL model as compared to the NJL and Born rate due to the suppression of color degrees of freedom.Comment: 5 pages, 7 figures, conference proceedings of the XXI DAE-BRNS HEP Symposium, IIT Guwahati, December 2014; to appear in 'Springer Proceedings in Physics Series

    Evidence of a metabolic memory to early-life dietary restriction in male C57BL/6 mice

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    <p>Background: Dietary restriction (DR) extends lifespan and induces beneficial metabolic effects in many animals. What is far less clear is whether animals retain a metabolic memory to previous DR exposure, that is, can early-life DR preserve beneficial metabolic effects later in life even after the resumption of ad libitum (AL) feeding. We examined a range of metabolic parameters (body mass, body composition (lean and fat mass), glucose tolerance, fed blood glucose, fasting plasma insulin and insulin-like growth factor 1 (IGF-1), insulin sensitivity) in male C57BL/6 mice dietary switched from DR to AL (DR-AL) at 11 months of age (mid life). The converse switch (AL-DR) was also undertaken at this time. We then compared metabolic parameters of the switched mice to one another and to age-matched mice maintained exclusively on an AL or DR diet from early life (3 months of age) at 1 month, 6 months or 10 months post switch.</p> <p>Results: Male mice dietary switched from AL-DR in mid life adopted the metabolic phenotype of mice exposed to DR from early life, so by the 10-month timepoint the AL-DR mice overlapped significantly with the DR mice in terms of their metabolic phenotype. Those animals switched from DR-AL in mid life showed clear evidence of a glycemic memory, with significantly improved glucose tolerance relative to mice maintained exclusively on AL feeding from early life. This difference in glucose tolerance was still apparent 10 months after the dietary switch, despite body mass, fasting insulin levels and insulin sensitivity all being similar to AL mice at this time.</p> <p>Conclusions: Male C57BL/6 mice retain a long-term glycemic memory of early-life DR, in that glucose tolerance is enhanced in mice switched from DR-AL in mid life, relative to AL mice, even 10 months following the dietary switch. These data therefore indicate that the phenotypic benefits of DR are not completely dissipated following a return to AL feeding. The challenge now is to understand the molecular mechanisms underlying these effects, the time course of these effects and whether similar interventions can confer comparable benefits in humans.</p&gt

    A genetic contribution from the Far East into Ashkenazi Jews via the ancient Silk Road

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    Contemporary Jews retain a genetic imprint from their Near Eastern ancestry, but obtained substantial genetic components from their neighboring populations during their history. Whether they received any genetic contribution from the Far East remains unknown, but frequent communication with the Chinese has been observed since the Silk Road period. To address this issue, mitochondrial DNA (mtDNA) variation from 55,595 Eurasians are analyzed. The existence of some eastern Eurasian haplotypes in eastern Ashkenazi Jews supports an East Asian genetic contribution, likely from Chinese. Further evidence indicates that this connection can be attributed to a gene flow event that occurred less than 1.4 kilo-years ago (kya), which falls within the time frame of the Silk Road scenario and fits well with historical records and archaeological discoveries. This observed genetic contribution from Chinese to Ashkenazi Jews demonstrates that the historical exchange between Ashkenazim and the Far East was not confined to the cultural sphere but also extended to an exchange of genes

    Association of Communication Between Hospital-based Physicians and Primary Care Providers with Patient Outcomes

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    Background: Patients admitted to general medicine inpatient services are increasingly cared for by hospital-based physicians rather than their primary care providers (PCPs). This separation of hospital and ambulatory care may result in important care discontinuities after discharge. We sought to determine whether communication between hospital-based physicians and PCPs influences patient outcomes. Methods: We approached consecutive patients admitted to general medicine services at six US academic centers from July 2001 to June 2003. A random sample of the PCPs for consented patients was contacted 2 weeks after patient discharge and surveyed about communication with the hospital medical team. Responses were linked with the 30-day composite patient outcomes of mortality, hospital readmission, and emergency department (ED) visits obtained through follow-up telephone survey and National Death Index search. We used hierarchical multi-variable logistic regression to model whether communication with the patient’s PCP was associated with the 30-day composite outcome. Results: A total of 1,772 PCPs for 2,336 patients were surveyed with 908 PCPs responses and complete patient follow-up available for 1,078 patients. The PCPs for 834 patients (77%) were aware that their patient had been admitted to the hospital. Of these, direct communication between PCPs and inpatient physicians took place for 194 patients (23%), and a discharge summary was available within 2 weeks of discharge for 347 patients (42%). Within 30 days of discharge, 233 (22%) patients died, were readmitted to the hospital, or visited an ED. In adjusted analyses, no relationship was seen between the composite outcome and direct physician communication (adjusted odds ratio 0.87, 95% confidence interval 0.56 – 1.34), the presence of a discharge summary (0.84, 95% CI 0.57–1.22), or PCP awareness of the index hospitalization (1.08, 95% CI 0.73–1.59). Conclusion: Analysis of communication between PCPs and inpatient medical teams revealed much room for improvement. Although communication during handoffs of care is important, we were not able to find a relationship between several aspects of communication and associated adverse clinical outcomes in this multi-center patient sample

    Potential of global croplands and bioenergy crops for climate change mitigation through deployment for enhanced weathering.

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    Conventional row crop agriculture for both food and fuel is a source of carbon dioxide (CO2) and nitrous oxide (N2O) to the atmosphere, and intensifying production on agricultural land increases the potential for soil C loss and soil acidification due to fertilizer use. Enhanced weathering (EW) in agricultural soils-applying crushed silicate rock as a soil amendment-is a method for combating global climate change while increasing nutrient availability to plants. EW uses land that is already producing food and fuel to sequester carbon (C), and reduces N2O loss through pH buffering. As biofuel use increases, EW in bioenergy crops offers the opportunity to sequester CO2 while reducing fossil fuel combustion. Uncertainties remain in the long-term effects and global implications of large-scale efforts to directly manipulate Earth's atmospheric CO2 composition, but EW in agricultural lands is an opportunity to employ these soils to sequester atmospheric C while benefitting crop production and the global climate

    Achieving temperature-size changes in a unicellular organism.

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    The temperature-size rule (TSR) is an intraspecific phenomenon describing the phenotypic plastic response of an organism size to the temperature: individuals reared at cooler temperatures mature to be larger adults than those reared at warmer temperatures. The TSR is ubiquitous, affecting >80% species including uni- and multicellular groups. How the TSR is established has received attention in multicellular organisms, but not in unicells. Further, conceptual models suggest the mechanism of size change to be different in these two groups. Here, we test these theories using the protist Cyclidium glaucoma. We measure cell sizes, along with population growth during temperature acclimation, to determine how and when the temperature-size changes are achieved. We show that mother and daughter sizes become temporarily decoupled from the ratio 2:1 during acclimation, but these return to their coupled state (where daughter cells are half the size of the mother cell) once acclimated. Thermal acclimation is rapid, being completed within approximately a single generation. Further, we examine the impact of increased temperatures on carrying capacity and total biomass, to investigate potential adaptive strategies of size change. We demonstrate no temperature effect on carrying capacity, but maximum supported biomass to decrease with increasing temperature

    The Political Economy of Non-Traditional Security: Explaining the Governance of Avian Influenza in Indonesia

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    Given the common association of non-traditional security (NTS) problems with globalisation, surprisingly little attention has been paid to how the political economy context of given NTS issues shape how they are securitised and managed in practice. We argue that security and its governance are always highly contested because different modes of security governance invariably privilege particular interests and normative agendas in state and society, which relate directly to the political economy. Drawing on critical political geography, we argue that, because NTS issues are perceived as at least potentially transnational, their securitisation often involves strategic attempts by actors and coalitions to ‘rescale’ their governance beyond the national political and institutional arenas, into new, expert-dominated modes of governance. Such efforts are often resisted by other coalitions, for which this rescaling is deleterious. As evidenced by a case study of avian influenza in Indonesia, particular governance outcomes depend upon the nature of the coalitions assembled for and against rescaling in specific situations, while these coalitions’ make-up and relative strength is shaped by the political economy of the industries that rescaling would affect, viewed against the broader backdrop of state-society relations

    Complete mitochondrial DNA sequences provide new insights into the Polynesian motif and the peopling of Madagascar

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    More than a decade of mitochondrial DNA (mtDNA) studies have given the 'Polynesian motif' renowned status as a marker for tracing the late-Holocene expansion of Austronesian speaking populations. Despite considerable research on the Polynesian motif in Oceania, there has been little equivalent work on the western edge of its expansion - leaving major issues unresolved regarding the motif's evolutionary history. This has also led to considerable uncertainty regarding the settlement of Madagascar. In this study, we assess mtDNA variation in 266 individuals from three Malagasy ethnic groups: the Mikea, Vezo, and Merina. Complete mtDNA genome sequencing reveals a new variant of the Polynesian motif in Madagascar; two coding region mutations define a Malagasy-specific sub-branch. This newly defined 'Malagasy motif' occurs at high frequency in all three ethnic groups (13-50%), and its phylogenetic position, geographic distribution, and estimated age all support a recent origin, but without conclusively identifying a specific source region. Nevertheless, the haplotype's limited diversity, similar to those of other mtDNA haplogroups found in our Malagasy groups, best supports a small number of initial settlers arriving to Madagascar through the same migratory process. Finally, the discovery of this lineage provides a set of new polymorphic positions to help localize the Austronesian ancestors of the Malagasy, as well as uncover the origin and evolution of the Polynesian motif itself
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