7,898 research outputs found

    Not all surveillance data are created equal—A multi‐method dynamic occupancy approach to determine rabies elimination from wildlife

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    1. A necessary component of elimination programmes for wildlife disease is effective surveillance. The ability to distinguish between disease freedom and non‐detection can mean the difference between a successful elimination campaign and new epizootics. Understanding the contribution of different surveillance methods helps to optimize and better allocate effort and develop more effective surveillance programmes. 2. We evaluated the probability of rabies virus elimination (disease freedom) in an enzootic area with active management using dynamic occupancy modelling of 10 years of raccoon rabies virus (RABV) surveillance data (2006–2015) collected from three states in the eastern United States. We estimated detection probability of RABV cases for each surveillance method (e.g. strange acting reports, roadkill, surveillance‐trapped animals, nuisance animals and public health samples) used by the USDA National Rabies Management Program. 3. Strange acting, found dead and public health animals were the most likely to detect RABV when it was present, and generally detectability was higher in fall– winter compared to spring–summer. Found dead animals in fall–winter had the highest detection at 0.33 (95% CI: 0.20, 0.48). Nuisance animals had the lowest detection probabilities (~0.02). 4. Areas with oral rabies vaccination (ORV) management had reduced occurrence probability compared to enzootic areas without ORV management. RABV occurrence was positively associated with deciduous and mixed forests and medium to high developed areas, which are also areas with higher raccoon (Procyon lotor) densities. By combining occupancy and detection estimates we can create a probability of elimination surface that can be updated seasonally to provide guidance on areas managed for wildlife disease. 5. Synthesis and applications. Wildlife disease surveillance is often comprised of a combination of targeted and convenience‐based methods. Using a multi‐method analytical approach allows us to compare the relative strengths of these methods, providing guidance on resource allocation for surveillance actions. Applying this multi‐method approach in conjunction with dynamic occupancy analyses better informs management decisions by understanding ecological drivers of disease occurrence

    The properties of brightest cluster galaxies in the Sloan Digital Sky Survey Data Release 6 adaptive matched filter cluster catalogue

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    We study the properties of brightest cluster galaxies (BCGs) drawn from a catalogue of more than 69 000 clusters in the Sloan Digital Sky Survey (SDSS) Data Release 6 based on the adaptive matched filter technique. Our sample consists of more than 14 300 galaxies in the redshift range 0.1-0.3. We test the catalogue by showing that it includes well-known BCGs which lie in the SDSS footprint. We characterize the Szabo et al. catalogue content in terms of BCGs r-band luminosities and optical colours as well as their trends with redshift. We find that the BCG luminosity distribution is close to a Gaussian with mean −22 mag and dispersion 0.54 mag. The mean has a redshift evolution broadly consistent with pure aging of the galaxies. Richer clusters tend to have brighter BCGs (mean −22.5 mag), however less dominant than in poorer systems. In particular, we define and study the fraction of blue BCGs, namely those that are likely to be missed by either colour-based cluster surveys and catalogues, as shown by a direct comparison to maxBCG clusters that are matched in the Szabo et al. catalogue. The overall fraction of blue BCGs goes from ∌5 per cent in the redshift range 0.1-0.2 to ∌10 per cent in the redshift bin 0.2-0.3, with the average over the whole sample of ∌8 per cent. We estimate the possible contamination due to blue outliers at the 1-2 per cent level, while errors on the photometric redshift may lead to an erroneous classification of >0.5 per cent of actual red BCGs as blue. When considering only galaxies with spectroscopic redshift available and for clusters above a richness of 50 - where the catalogue is more than 85 per cent complete - our conservative estimate of the blue fraction is 1-6 per cent (at 99.6 per cent confidence). A preliminary morphological study suggests that the increase in the blue fraction at lower richnesses may have a non-negligible contribution from spiral galaxies. Finally, we cross-matched our catalogue with the ACCEPT cluster sample, and find that blue BCGs tend to be in clusters with low entropy and short cooling times. That is, the blue light is presumably due to recent star formation associated to gas feeding by cooling flow

    Classical field theory on Lie algebroids: Variational aspects

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    The variational formalism for classical field theories is extended to the setting of Lie algebroids. Given a Lagrangian function we study the problem of finding critical points of the action functional when we restrict the fields to be morphisms of Lie algebroids. In addition to the standard case, our formalism includes as particular examples the case of systems with symmetry (covariant Euler-Poincare and Lagrange Poincare cases), Sigma models or Chern-Simons theories.Comment: Talk deliverd at the 9th International Conference on Differential Geometry and its Applications, Prague, September 2004. References adde

    More about orbitally excited hadrons from lattice QCD

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    This is a second paper describing the calculation of spectroscopy for orbitally excited states from lattice simulations of Quantum Chromodynamics. New features include higher statistics for P-wave systems and first results for the spectroscopy of D-wave mesons and baryons, for relatively heavy quark masses. We parameterize the Coulomb gauge wave functions for P-wave and D-wave systems and compare them to those of their corresponding S-wave states.Comment: 21 pages plus 14 figs, 3 include

    Cyclotron Resonance in the Layered Perovskite Superconductor Sr2RuO4

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    We have measured the cyclotron masses in Sr2RuO4 through the observation of periodic-orbit-resonances - a magnetic resonance technique closely related to cyclotron resonance. We obtain values for the alpha, beta and gamma Fermi surfaces of (4.33+/-0.05)me, (5.81+/-0.03)me and (9.71+/-0.11)me respectively. The appreciable differences between these results and those obtained from de Haas- van Alphen measurements are attributable to strong electron-electron interactions in this system. Our findings appear to be consistent with predictions for a strongly interacting Fermi liquid; indeed, semi-quantitative agreement is obtained for the electron pockets beta and gamma.Comment: 4 pages + 3 figure

    Berom cultural beliefs and attitudes towards mental health problems in Nigeria: a mixed-methods study

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    Beliefs and attitudes are essential in mental health discourse. However, cultural beliefs and attitudes towards mental health problems (ATMHPs) among the Berom people of Nigeria are under-researched. The present studies made original contributions using the Cultural Identity Model (CIM) as predictors to investigate ATMHPs, and semi-structured interviews to further explain the potential impact of cultural beliefs on MHPs. In study-1, N = 140 participants responded to questionnaires on ATMHPs and were analysed using multivariate multiple regression in RStudio. Study-2 interviewed N = 13 participants (n = 7 laypeople; n = 6 practitioners). Interviews were recorded, transcribed and analysed thematically. Study-1 findings showed CIM as a non-significant predictor of ATMHPs. However, in study-2, four themes emerged: Cultural beliefs that MHPs are caused by spiritual forces; Berom indigenous preference for traditional healing; Christian religious healing in Berom communities; and Western-trained mental health practitioners' perception of lay service-users. The authors concluded that the Berom traditional and Christian religious healings are beneficial

    Ginzburg-Landau Theory for a p-Wave Sr_2RuO_4 Superconductor: Vortex Core Structure and Extended London Theory

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    Based on a two dimensional odd-parity superconducting order parameter for Sr_2RuO_4 with p-wave symmetry, we investigate the single vortex and vortex lattice structure of the mixed phase near H_{c1}. Ginzburg-Landau calculations for a single vortex show a fourfold structure with an orientation depending on the microscopic Fermi surface properties. The corresponding extended London theory is developed to determine the vortex lattice structure and we find near H_{c1} a centered rectangular vortex lattice. As the field is increased from H_{c1} this lattice continuously deforms until a square vortex lattice is achieved. In the centered rectangular phase the field distribution, as measurable through \mu-SR experiments, exhibits a characteristic two peak structure (similar to that predicted in high temperature and borocarbide superconductors).Comment: 12 pages, 7 figure

    Interaction between vortices in models with two order parameters

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    The interaction energy and force between widely separated strings is analyzed in a field theory having applications to superconducting cosmic strings, the SO(5) model of high-temperature superconductivity, and solitons in nonlinear optics. The field theory has two order parameters, one of which is broken in the vacuum (giving rise to strings), the other of which is unbroken in the vacuum but which could nonetheless be broken in the core of the string. If this does occur, there is an effect on the energetics of widely separated strings. This effect is important if the length scale of this second order parameter is longer than that of the other fields in the problem.Comment: 11 pages, 3 figures. Minor changes in the text. Accepted for publication in Phys. Rev.
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