585 research outputs found

    Fecundity compensation and tolerance to a sterilizing pathogen in <em>Daphnia</em>

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    Hosts are armed with several lines of defence in the battle against parasites: they may prevent the establishment of infection, reduce parasite growth once infected or persevere through mechanisms that reduce the damage caused by infection, called tolerance. Studies on tolerance in animals have focused on mortality, and sterility tolerance has not been investigated experimentally. Here, we tested for genetic variation in the multiple steps of defence when the invertebrate Daphnia magna is infected with the sterilizing bacterial pathogen Pasteuria ramosa: anti-infection resistance, anti-growth resistance and the ability to tolerate sterilization once infected. When exposed to nine doses of a genetically diverse pathogen inoculum, six host genotypes varied in their average susceptibility to infection and in their parasite loads once infected. How host fecundity changed with increasing parasite loads did not vary between genotypes, indicating that there was no genetic variation for this measure of fecundity tolerance. However, genotypes differed in their level of fecundity compensation under infection, and we discuss how, by increasing host fitness without targeting parasite densities, fecundity compensation is consistent with the functional definition of tolerance. Such infection-induced life-history shifts are not traditionally considered to be part of the immune response, but may crucially reduce harm (in terms of fitness loss) caused by disease, and are a distinct source of selection on pathogens

    Housing and Accommodation Support Initiative 1 Evaluation: Care Planning Report

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    The Housing and Accommodation Support Initiative (HASI) is a program funded by NSW Health and NSW Department of Housing, in partnership with nongovernment organisations (NGO). HASI provides a stable, consistent and integrated hospital to community care system for people with mental illness and associated psychiatric disability. This is achieved through providing practical assistance, intensive psychosocial support, clinical care and secure housing, along with opportunities, options and hope to people who have a mental illness (referred to here as consumers). This report examines the care planning practices of NGO Accommodation Support Providers (ASPs) in HASI Stage One. Funded by NSW Health, it extends a comprehensive evaluation of HASI One completed by the Social Policy Research Centre, (Muir et al, 2007). It has been undertaken as a result of the recommendations from that evaluation, which indicated the need to review and evaluate care planning in more detail. Methods included fieldwork in three of the nine HASI One sites (Section 1.1), including interviews with 20 consumers who participated in HASI, other people directly involved in their care planning, as well as an examination of their care plans

    A Singular Perturbation Analysis for \\Unstable Systems with Convective Nonlinearity

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    We use a singular perturbation method to study the interface dynamics of a non-conserved order parameter (NCOP) system, of the reaction-diffusion type, for the case where an external bias field or convection is present. We find that this method, developed by Kawasaki, Yalabik and Gunton for the time-dependant Ginzburg-Landau equation and used successfully on other NCOP systems, breaks down for our system when the strength of bias/convection gets large enough.Comment: 5 pages, PostScript forma

    Can brewer-sponsored ‘drink responsibly’ warning message be effective without alcohol policies in Nigeria?

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    Alcohol availability, use and misuse and their related problems are rising in many parts of the African continent and this has been attributed to many factors such as non-existent or ineffective regulatory measures. In contemporary Nigeria, while a culture of intoxication is growing, there are no regulatory measures in the form of alcohol policies to reduce it. What exists is brewer-sponsored self-regulation. This paper therefore, critically analyses this self-imposed 'drink responsibly' warning message, arguing that because responsible drinking messages are strategically designed to serve the interest of alcohol industries, it cannot be effective. The paper further argues that because there are no definitions of standard drinks and where alcohol by volume (ABV) is scarcely inscribed on product labels of alcoholic beverages, such message will remain ineffective. Therefore, it recommends that an urgent step should be taken by the government to formulate and implement comprehensive evidence-based alcohol policies in Nigeria

    Facts, Values and Quanta

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    Quantum mechanics is a fundamentally probabilistic theory (at least so far as the empirical predictions are concerned). It follows that, if one wants to properly understand quantum mechanics, it is essential to clearly understand the meaning of probability statements. The interpretation of probability has excited nearly as much philosophical controversy as the interpretation of quantum mechanics. 20th century physicists have mostly adopted a frequentist conception. In this paper it is argued that we ought, instead, to adopt a logical or Bayesian conception. The paper includes a comparison of the orthodox and Bayesian theories of statistical inference. It concludes with a few remarks concerning the implications for the concept of physical reality.Comment: 30 pages, AMS Late

    The Virtual International Stroke Trials Archive

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    BACKGROUND AND PURPOSE: Stroke has global importance and it causes an increasing amount of human suffering and economic burden, but its management is far from optimal. The unsuccessful outcome of several research programs highlights the need for reliable data on which to plan future clinical trials. The Virtual International Stroke Trials Archive aims to aid the planning of clinical trials by collating and providing access to a rich resource of patient data to perform exploratory analyses. METHODS: Data were contributed by the principal investigators of numerous trials from the past 16 years. These data have been centrally collated and are available for anonymized analysis and hypothesis testing. RESULTS: Currently, the Virtual International Stroke Trials Archive contains 21 trials. There are data on \u3e15,000 patients with both ischemic and hemorrhagic stroke. Ages range between 18 and 103 years, with a mean age of 69+/-12 years. Outcome measures include the Barthel Index, Scandinavian Stroke Scale, National Institutes of Health Stroke Scale, Orgogozo Scale, and modified Rankin Scale. Medical history and onset-to-treatment time are readily available, and computed tomography lesion data are available for selected trials. CONCLUSIONS: This resource has the potential to influence clinical trial design and implementation through data analyses that inform planning

    Correlation functions in a c=1 boundary conformal field theory

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    We obtain exact results for correlation functions of primary operators in the two-dimensional conformal field theory of a scalar field interacting with a critical periodic boundary potential. Amplitudes involving arbitrary bulk discrete primary fields are given in terms of SU(2) rotation coefficients while boundary amplitudes involving discrete boundary fields are independent of the boundary interaction. Mixed amplitudes involving both bulk and boundary discrete fields can also be obtained explicitly. Two- and three-point boundary amplitudes involving fields at generic momentum are determined, up to multiplicative constants, by the band spectrum in the open-string sector of the theory.Comment: 33 pages, 6 figure

    Optimal estimation of qubit states with continuous time measurements

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    We propose an adaptive, two steps strategy, for the estimation of mixed qubit states. We show that the strategy is optimal in a local minimax sense for the trace norm distance as well as other locally quadratic figures of merit. Local minimax optimality means that given nn identical qubits, there exists no estimator which can perform better than the proposed estimator on a neighborhood of size n−1/2n^{-1/2} of an arbitrary state. In particular, it is asymptotically Bayesian optimal for a large class of prior distributions. We present a physical implementation of the optimal estimation strategy based on continuous time measurements in a field that couples with the qubits. The crucial ingredient of the result is the concept of local asymptotic normality (or LAN) for qubits. This means that, for large nn, the statistical model described by nn identically prepared qubits is locally equivalent to a model with only a classical Gaussian distribution and a Gaussian state of a quantum harmonic oscillator. The term `local' refers to a shrinking neighborhood around a fixed state ρ0\rho_{0}. An essential result is that the neighborhood radius can be chosen arbitrarily close to n−1/4n^{-1/4}. This allows us to use a two steps procedure by which we first localize the state within a smaller neighborhood of radius n−1/2+Ï”n^{-1/2+\epsilon}, and then use LAN to perform optimal estimation.Comment: 32 pages, 3 figures, to appear in Commun. Math. Phy
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