3,101 research outputs found

    from The Anatomy Of Melon Collie The Munificent Seven

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    Invisible Quarkonium Decays as a Sensitive Probe of Dark Matter

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    We examine in a model-independent manner the measurements that can be performed at B-factories with sensitivity to dark matter. If a singlet scalar, pseudo-scalar, or vector is present and mediates the Standard Model - dark matter interaction, it can mediate invisible decays of quarkonium states such as the Υ\Upsilon, J/ΨJ/\Psi, and η\eta. Such scenarios have arisen in the context of supersymmetry, extended Higgs sectors, solutions the supersymmetric μ\mu problem, and extra U(1) gauge groups from grand unified theories and string theory. Existing B-factories running at the Υ(4S)\Upsilon(4S) can produce lower Υ\Upsilon resonances by emitting an Initial State Radiation (ISR) photon. Using a combination of ISR and radiative decays, the initial state of an invisibly decaying quarkonium resonance can be tagged, giving sensitivity to the spin and CP-nature of the particle that mediates standard model-dark matter interactions. These measurements can discover or place strong constraints on dark matter scenarios where the dark matter is approximately lighter than the bb-quark. For the decay chains Υ(nS)π+πΥ(1S)\Upsilon(nS) \to \pi^+ \pi^- \Upsilon(1S) (n=2,3) we analyze the dominant backgrounds and determine that with 400fb1400 fb^{-1} collected at the Υ(4S)\Upsilon(4S), the B-factories can limit BR(\Upsilon(1S) \to invisible) \lsim 0.1%.Comment: 20 pages, 1 figure, accepted for publication in PR

    Bayesian Hierarchical Modelling for Tailoring Metric Thresholds

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    Software is highly contextual. While there are cross-cutting `global' lessons, individual software projects exhibit many `local' properties. This data heterogeneity makes drawing local conclusions from global data dangerous. A key research challenge is to construct locally accurate prediction models that are informed by global characteristics and data volumes. Previous work has tackled this problem using clustering and transfer learning approaches, which identify locally similar characteristics. This paper applies a simpler approach known as Bayesian hierarchical modeling. We show that hierarchical modeling supports cross-project comparisons, while preserving local context. To demonstrate the approach, we conduct a conceptual replication of an existing study on setting software metrics thresholds. Our emerging results show our hierarchical model reduces model prediction error compared to a global approach by up to 50%.Comment: Short paper, published at MSR '18: 15th International Conference on Mining Software Repositories May 28--29, 2018, Gothenburg, Swede

    Screening for health risks: A social science perspective

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    Health screening promises to reduce risks to individuals via probabilistic sifting of populations for medical conditions. The categorisation and selection of 'conditions' such as cardiovascular events, dementia and depression for screening itself requires prior interpretive labour which usually remains unexamined. Screening systems can take diverse organisational forms and varying relationships to health status, as when purported disease precursors, for example 'pre-cancerous' polyps, or supposed risk factors, such as high cholesterol themselves, become targets for screening. Screening at best yields small, although not necessarily unworthwhile, net population health gains. It also creates new risks, leaving some individuals worse-off than if they had been left alone. The difficulties associated with attempting to measure small net gains through randomised controlled trials are sometimes underestimated. Despite endemic doubts about its clinical utility, bibliometric analysis of published papers shows that responses to health risks are coming to be increasingly thought about in terms of screening. This shift is superimposed on a strengthening tendency to view health through the lens of risk. It merits further scrutiny as a societal phenomenon

    A Latent Variable Approach to Multivariate Quantitative Trait Loci

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    A novel approach based on latent variable modelling is presented for the analysis of multivariate quantitative and qualitative trait loci. The approach is general in the sense that it enables the joint analysis of many kinds of quantitative and qualitative traits (including count data and censored traits) in a single modelling framework. In the framework, the observations are modelled as functions of latent variables, which are then affected by quantitative trait loci. Separating the analysis in this way means that measurement errors in the phenotypic observations can be included easily in the model, providing robust inferences. The performance of the method is illustrated using two real multivariate datasets, from barley and Scots pine

    Determining The Cost Effectiveness Of Solutions To Diffuse Pollution: Developing A Model To Assess In-Field Mitigation Options for Phosphorous and Sediment Loss

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    The European Union Water Framework Directive requires governments to set water quality objectives based on good ecological status. This includes specific requirements to control diffuse pollution. Diffuse phosphorous (P) pollution plays a pivotal role in influencing water quality with losses of P associated with soil particles often linked to soil erosion. The Mitigation Options for Phosphorus and Sediment (MOPS) project, using three case study sites, is investigating the cost effectiveness of specific control measures in terms of mitigating sediment and P loss from combinable crops. The analysis is conducted at the farm level using a simple spreadsheet model. Further development of the model will allow the results to be extrapolated to generic regional farm typologies. Results from the initial farm level analysis suggest that some mitigation options may not be cost effective in reducing diffuse pollution, however, that other options may be very cost effective.Resource /Energy Economics and Policy,

    From fish and forest to salt and shrimp: the changing nature of coastal development policy and its impact on coastal resources and communities in Southeast Bangladesh

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    Coastal Bangladesh is both rich in aquatic and terrestrial resources and subject to natural and humanmade risks and vulnerabilities of flood, cyclone, political change, competition for resources, deforestation, piracy and the like. Since the 1950s, two of the most important transformations in land use along the coastal region of Southeast Bangladesh have been the growth of solar evaporative salt production (from an older salt sector) and the introduction of export shrimp culture. This paper traces the development of these two 'industries' over the past 50 years in the southern part of the southeast coastal region. It summarises their impact on longstanding land and aquatic use practices such as fishing, farming and forestry and on the lives of people dependent upon these practices. Through a case study of the Chakoria Sundarban, it illustrates the piecemeal and fragmented approach to coastal development of the East Pakistan and Bangladesh governments since 1950 to the 1990s. Finally, it describes briefly the new Integrated Coastal Zone Management Plan set for implementation in 2006, which promises to provide a more inclusive and integrated approach to coastal planning
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