3,123 research outputs found
Invisible Quarkonium Decays as a Sensitive Probe of Dark Matter
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 , , and . Such scenarios have arisen in the
context of supersymmetry, extended Higgs sectors, solutions the supersymmetric
problem, and extra U(1) gauge groups from grand unified theories and
string theory. Existing B-factories running at the can produce
lower 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
-quark. For the decay chains
(n=2,3) we analyze the dominant backgrounds and determine that with collected at the , 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
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
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Assessing the probability of patients reoffending after discharge from low to medium secure forensic mental health services: An inductive prevention paradox
Citizens of developed societies are troubled by those who commit ‘irrational' crimes against the person. Reoffending by ex-patients following their release from secure mental health services triggers particularly intense angst when amplified by media and political scrutiny. Forensic mental health service providers are expected to minimise the occurrence of such transgressions by releasing only those patients who are judged acceptably unlikely to reoffend. However, reoffending probabilities can only be estimated by observing behaviour in secure institutional settings designed specifically to prevent patients from transgressing. The article explores this ‘inductive prevention paradox' which arises when the implementation of measures designed to avoid an adverse event obscures direct observation of what might have happened if prophylaxis had not been attempted. The analysis presented draws on data obtained in 1999–2003 from two qualitative studies in medium to low secure UK institutions, one providing forensic mental health services and the other forensic learning disability services. We explored the views of 56 staff members and 21 patients about risk management in forensic services and undertook additional 25 staff interviews for case studies of the 21 patients. The wider applicability of the inductive prevention paradox will be considered in the Discussion. We argue that the prognostic limitations arising from prevention have been underestimated by policy makers and in official inquiries; and that the prevailing personal risk assessment framework needs to be complemented by greater attention to the environments which patients will be discharged into
Screening for health risks: A social science perspective
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
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
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
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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