1,134 research outputs found

    Energy loss in a strongly coupled anisotropic plasma

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    We study the energy loss of a rotating infinitely massive quark moving, at constant velocity, through an anisotropic strongly-coupled N=4 plasma from holography. It is shown that, similar to the isotropic plasma, the energy loss of the rotating quark is due to either the drag force or radiation with a continuous crossover from drag-dominated regime to the radiation dominated regime. We find that the anisotropy has a significant effect on the energy loss of the heavy quark, specially in the crossover regime. We argue that the energy loss due to radiation in anisotropic media is less than the isotropic case. Interestingly this is similar to analogous calculations for the energy loss in weakly coupled anisotropic plasma.Comment: 26+1 pages, 10 figures, typos fixe

    Prevalence and factors associated with extra-spousal partnerships among currently married individuals in Rakai, Uganda: A Cross-sectional study.

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    Introduction While extra-marital relations have been associated with increased risk for HIV infection in previous studies, extant literature on the prevalence and factors associated with these sexual relationships remains largely limited. We assessed the prevalence and factors associated with extra-spousal partnerships among currently married individuals. Methods This secondary analysis uses data from a large cross-sectional study conducted among married individuals aged 15-49 years in Rakai, Uganda. We used a generic definition of marriage to include all individuals who considered themselves as “married” irrespective of category. Extra-spousal sexual partnerships were defined as concurrent sexual relationships between a married individual and another person (of the opposite sex) with whom they were not currently married. We determined the prevalence of extra-spousal partnerships and used a modified Poisson regression model to assess factors independently associated (at P<0.05) with extra-spousal partnerships, after adjusting for potential confounders. We used STATA (version 14.0) for data analysis. Results Of 2,103 currently married individuals, 51.5% (n=1,084) were females; 66.1% (n=1,391) were in their first marriage ever, while 83.3% (n=1,751) had been married for five or more (5+) years. Thirteen per cent (n=282) reported extra-spousal partnerships; 4.5% (n=49) among females and 22.9% (n=233) among males. Being HIV-positive, being in the third or higher marital order marriage, engagement in housework (among women), and being male were significantly associated with engaging in extra-spousal partnerships. Being 35 years or older was protective against engaging in extra-spousal partnerships. Conclusion One in ten currently married individuals engaged in extra-spousal partnerships. Extra-spousal partnerships were more common among men, individuals living with HIV, those with a higher number of previous marriages, and women engaged in housework than their counterparts. Recommendations Targeted HIV prevention interventions, including those that focus on men and previously married individuals, are urgently needed to protect married individuals from the risk of extra-spousal partnerships

    Vaccination against Foot-and-mouth disease : do initial conditions affect its benefit?

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    When facing incursion of a major livestock infectious disease, the decision to implement a vaccination programme is made at the national level. To make this decision, governments must consider whether the benefits of vaccination are sufficient to outweigh potential additional costs, including further trade restrictions that may be imposed due to the implementation of vaccination. However, little consensus exists on the factors triggering its implementation on the field. This work explores the effect of several triggers in the implementation of a reactive vaccination-to-live policy when facing epidemics of foot-and-mouth disease. In particular, we tested whether changes in the location of the incursion and the delay of implementation would affect the epidemiological benefit of such a policy in the context of Scotland. To reach this goal, we used a spatial, premises-based model that has been extensively used to investigate the effectiveness of mitigation procedures in Great Britain. The results show that the decision to vaccinate, or not, is not straightforward and strongly depends on the underlying local structure of the population-at-risk. With regards to disease incursion preparedness, simply identifying areas of highest population density may not capture all complexities that may influence the spread of disease as well as the benefit of implementing vaccination. However, if a decision to vaccinate is made, we show that delaying its implementation in the field may markedly reduce its benefit. This work provides guidelines to support policy makers in their decision to implement, or not, a vaccination-to-live policy when facing epidemics of infectious livestock disease

    Early-Time Energy Loss in a Strongly-Coupled SYM Plasma

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    We carry out an analytic study of the early-time motion of a quark in a strongly-coupled maximally-supersymmetric Yang-Mills plasma, using the AdS/CFT correspondence. Our approach extracts the first thermal effects as a small perturbation of the known quark dynamics in vacuum, using a double expansion that is valid for early times and for (moderately) ultrarelativistic quark velocities. The quark is found to lose energy at a rate that differs significantly from the previously derived stationary/late-time result: it scales like T^4 instead of T^2, and is associated with a friction coefficient that is not independent of the quark momentum. Under conditions representative of the quark-gluon plasma as obtained at RHIC, the early energy loss rate is a few times smaller than its late-time counterpart. Our analysis additionally leads to thermally-corrected expressions for the intrinsic energy and momentum of the quark, in which the previously discovered limiting velocity of the quark is found to appear naturally.Comment: 39 pages, no figures. v2: Minor corrections and clarifications. References added. Version to be published in JHE

    Search for new phenomena in final states with an energetic jet and large missing transverse momentum in pp collisions at √ s = 8 TeV with the ATLAS detector

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    Results of a search for new phenomena in final states with an energetic jet and large missing transverse momentum are reported. The search uses 20.3 fb−1 of √ s = 8 TeV data collected in 2012 with the ATLAS detector at the LHC. Events are required to have at least one jet with pT > 120 GeV and no leptons. Nine signal regions are considered with increasing missing transverse momentum requirements between Emiss T > 150 GeV and Emiss T > 700 GeV. Good agreement is observed between the number of events in data and Standard Model expectations. The results are translated into exclusion limits on models with either large extra spatial dimensions, pair production of weakly interacting dark matter candidates, or production of very light gravitinos in a gauge-mediated supersymmetric model. In addition, limits on the production of an invisibly decaying Higgs-like boson leading to similar topologies in the final state are presente

    Towards the development of a DNA-sequence based approach to serotyping of Salmonella enterica

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    BACKGROUND: The fliC and fljB genes in Salmonella code for the phase 1 (H1) and phase 2 (H2) flagellin respectively, the rfb cluster encodes the majority of enzymes for polysaccharide (O) antigen biosynthesis, together they determine the antigenic profile by which Salmonella are identified. Sequencing and characterisation of fliC was performed in the development of a molecular serotyping technique. RESULTS: FliC sequencing of 106 strains revealed two groups; the g-complex included those exhibiting "g" or "m,t" antigenic factors, and the non-g strains which formed a second more diverse group. Variation in fliC was characterised and sero-specific motifs identified. Furthermore, it was possible to identify differences in certain H antigens that are not detected by traditional serotyping. A rapid short sequencing assay was developed to target serotype-specific sequence motifs in fliC. The assay was evaluated for identification of H1 antigens with a panel of 55 strains. CONCLUSION: FliC sequences were obtained for more than 100 strains comprising 29 different H1 alleles. Unique pyrosequencing profiles corresponding to the H1 component of the serotype were generated reproducibly for the 23 alleles represented in the evaluation panel. Short read sequence assays can now be used to identify fliC alleles in approximately 97% of the 50 medically most important Salmonella in England and Wales. Capability for high throughput testing and automation give these assays considerable advantages over traditional methods

    Integrating livelihoods and conservation in protected areas: Understanding the role and stakeholder views on prospects for non-timber forest products, a Bangladesh case study

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    Protected areas (PAs) represent a key global strategy in biodiversity conservation. In tropical developing countries, the management of PAs is a great challenge as many contain resources on which local communities rely. Collection and trading of non-timber forest products (NTFPs) is a well-established forest-based livelihood strategy, which has been promoted as a potential means for enhanced conservation and improved rural livelihoods in recent years, even though the sustainability or ecological implications have rarely been tested. We conducted an exploratory survey to understand the role and stakeholder views on conservation prospects and perceived ecological feasibility of NTFPs and harvesting schemes in a northeastern PA of Bangladesh, namely the Satchari National Park. Households (n = 101) were interviewed from three different forest dependency categories, adopting a stratified random sampling approach and using a semi-structured questionnaire. The study identified 13 locally important NTFPs, with five being critically important to supporting local livelihoods. Our study suggests that collection, processing and trading in NTFPs constitutes the primary occupation for about 18% of local inhabitants and account for an estimated 19% of their cash annual income. The household consensus on issues relating to NTFPs and their prospective role in conservation was surprisingly high, with 48% of respondents believing that promotion of NTFPs in the PA could have positive conservation value. The majority (71%) of households also had some understanding of the ecological implications of NTFP harvesting, sustainability (53%) and possible management and monitoring regimes (100%). With little known about their real application in the field, our study suggests further investigations are required to understand the ecological compatibility of traditional NTFP harvesting patterns and management. © 2010 Taylor & Francis

    Patients' experiences of living with and receiving treatment for fibromyalgia syndrome: a qualitative study

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    Background: Fibromyalgia syndrome (FMS) presents a challenge for patients and health care staff across many medical specialities. The aetiology is multi-dimensional, involving somatic, psychological and social factors. Patients' views were obtained to understand their experience of living with this long-term condition, using qualitative interviews. Methods: 12 patients were recruited and stratified by age, gender and ethnicity from one rheumatology outpatient clinic, and a departmental held database of patients diagnosed with FMS. Results: Patients' accounts of their experience of FMS resonated well with two central concepts: social identity and illness intrusiveness. These suggested three themes for the analytical framework: life before and after diagnosis (e.g. lack of information about FMS, invisibility of FMS); change in health identity (e.g. mental distress, impact on social life) and perceived quality of care (e.g. lack of contact with nurses, attitudes of specialists). The information provided from one male participant did not differ from the female patients, but black and ethnic community patients expressed a degree of suspicion towards the medication prescribed, and the attitudes displayed by some doctors, a finding that has not been previously reported amongst this patient group. Patients expected more consultation time and effective treatment than they received. Subjective experiences and objective physical and emotional changes were non-overlapping. Patients' accounts revealed that their physical, mental and social health was compromised, at times overwhelming and affected their identity. Conclusion: FMS is a condition that intrudes upon many aspects of patients' lives and is little understood. At the same time, it is a syndrome that evokes uneasiness in health care staff ( as current diagnostic criteria are not well supported by objective markers of physiological or biochemical nature, and indeed because of doubt about the existence of the condition) and places great demands on resources in clinical practice. Greater attention needs to be paid to the links between the explanatory models of patients and staff, and most important, to the interrelationship between the complex physical, psychological and social needs of patients with FMS. Taking a less medical but more holistic approach when drawing up new diagnostic criteria for FMS might match better individuals' somatic and psycho-social symptom profile and may result in more effective treatment

    Higher risk of gastrointestinal parasite infection at lower elevation suggests possible constraints in the distributional niche of Alpine marmots

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    Alpine marmots Marmota marmota occupy a narrow altitudinal niche within high elevation alpine environments. For animals living at such high elevations where resources are limited, parasitism represents a potential major cost in life history. Using occupancy models, we tested if marmots living at higher elevation have a reduced risk of being infected with gastrointestinal helminths, possibly compensating the lower availability of resources (shorter feeding season, longer snow cover and lower temperature) than marmots inhabiting lower elevations. Detection probability of eggs and oncospheres of two gastro-intestinal helminthic parasites, Ascaris laevis and Ctenotaenia marmotae, sampled in marmot feces, was used as a proxy of parasite abundance. As predicted, the models showed a negative relationship between elevation and parasite detectability (i.e. abundance) for both species, while there appeared to be a negative effect of solar radiance only for C. marmotae. Site-occupancy models are used here for the first time to model the constrains of gastrointestinal parasitism on a wild species and the relationship existing between endoparasites and environmental factors in a population of free-living animals. The results of this study suggest the future use of site-occupancy models as a viable tool to account for parasite imperfect detection in ecoparasitological studies, and give useful insights to further investigate the hypothesis of the contribution of parasite infection in constraining the altitudinal niche of Alpine marmots

    A narrative review on the similarities and dissimilarities between myalgic encephalomyelitis/chronic fatigue syndrome (me/cfs) and sickness behavior

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    It is of importance whether myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a variant of sickness behavior. The latter is induced by acute infections/injury being principally mediated through proinflammatory cytokines. Sickness is a beneficial behavioral response that serves to enhance recovery, conserves energy and plays a role in the resolution of inflammation. There are behavioral/symptomatic similarities (for example, fatigue, malaise, hyperalgesia) and dissimilarities (gastrointestinal symptoms, anorexia and weight loss) between sickness and ME/CFS. While sickness is an adaptive response induced by proinflammatory cytokines, ME/CFS is a chronic, disabling disorder, where the pathophysiology is related to activation of immunoinflammatory and oxidative pathways and autoimmune responses. While sickness behavior is a state of energy conservation, which plays a role in combating pathogens, ME/CFS is a chronic disease underpinned by a state of energy depletion. While sickness is an acute response to infection/injury, the trigger factors in ME/CFS are less well defined and encompass acute and chronic infections, as well as inflammatory or autoimmune diseases. It is concluded that sickness behavior and ME/CFS are two different conditions
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