603 research outputs found

    Conditions for entanglement in multipartite systems

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    We introduce two entanglement conditions that take the form of inequalities involving expectation values of operators. These conditions are sufficient conditions for entanglement, that is if they are satisfied the state is entangled, but if they are not, one can say nothing about the entanglement of the state. These conditions are quite flexible, because the operators in them are not specified, and they are particularly useful in detecting multipartite entanglement. We explore the range of utility of these conditions by considering a number of examples of entangled states, and seeing under what conditions entanglement in them can be detected by the inequalities presented here.Comment: accepted for publication in Physical Review

    Multi-Wavelength Variability of the Synchrotron Self-Compton Model for Blazar Emission

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    Motivated by recent reports of strongly correlated radio and X-ray variability in 3C279 (Grandi, etal 1995), we have computed the relative amplitudes of variations in the synchrotron flux at ν\nu and the self-Compton X-ray flux at 1 keV (R(ν)R(\nu)) for a homogeneous sphere of relativistic electrons orbiting in a tangled magnetic field. Relative to synchrotron self-Compton scattering without induced Compton scattering, stimulated scattering reduces the amplitude of R(ν)R(\nu) by as much as an order of magnitude when \tau_T \gtwid 1. When τT\tau_T varies in a fixed magnetic field, RτR_{\tau} increases monotonically from 0.01 at νo\nu_o, the self-absorption turnover frequency, to 0.50.5 at 100νo100 \nu_o. The relative amplitudes of the correlated fluctuations in the radio-mm and X-ray fluxes from 3C279 are consistent with the synchrotron self-Compton model if τT\tau_T varies in a fixed magnetic field and induced Compton scattering is the dominant source of radio opacity. The variation amplitudes are are too small to be produced by the passage of a shock through the synchrotron emission region unless the magnetic field is perpendicular to the shock front.Comment: 21 pages, 4 fig

    Mapping hotspots of malaria transmission from pre-existing hydrology, geology and geomorphology data in the pre-elimination context of Zanzibar, United Republic of Tanzania

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    Background: Larval source management strategies can play an important role in malaria elimination programmes, especially for tackling outdoor biting species and for eliminating parasite and vector populations when they are most vulnerable during the dry season. Effective larval source management requires tools for identifying geographic foci of vector proliferation and malaria transmission where these efforts may be concentrated. Previous studies have relied on surface topographic wetness to indicate hydrological potential for vector breeding sites, but this is unsuitable for karst (limestone) landscapes such as Zanzibar where water flow, especially in the dry season, is subterranean and not controlled by surface topography. Methods: We examine the relationship between dry and wet season spatial patterns of diagnostic positivity rates of malaria infection amongst patients reporting to health facilities on Unguja, Zanzibar, with the physical geography of the island, including land cover, elevation, slope angle, hydrology, geology and geomorphology in order to identify transmission hot spots using Boosted Regression Trees (BRT) analysis. Results: The distribution of both wet and dry season malaria infection rates can be predicted using freely available static data, such as elevation and geology. Specifically, high infection rates in the central and southeast regions of the island coincide with outcrops of hard dense limestone which cause locally elevated water tables and the location of dolines (shallow depressions plugged with fine-grained material promoting the persistence of shallow water bodies). Conclusions: This analysis provides a tractable tool for the identification of malaria hotspots which incorporates subterranean hydrology, which can be used to target larval source management strategies

    Habitat Hydrology and Geomorphology Control the Distribution of Malaria Vector Larvae in Rural Africa

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    Larval source management is a promising component of integrated malaria control and elimination. This requires development of a framework to target productive locations through process-based understanding of habitat hydrology and geomorphology. We conducted the first catchment scale study of fine resolution spatial and temporal variation in Anopheles habitat and productivity in relation to rainfall, hydrology and geomorphology for a high malaria transmission area of Tanzania. Monthly aggregates of rainfall, river stage and water table were not significantly related to the abundance of vector larvae. However, these metrics showed strong explanatory power to predict mosquito larval abundances after stratification by water body type, with a clear seasonal trend for each, defined on the basis of its geomorphological setting and origin. Hydrological and geomorphological processes governing the availability and productivity of Anopheles breeding habitat need to be understood at the local scale for which larval source management is implemented in order to effectively target larval source interventions. Mapping and monitoring these processes is a well-established practice providing a tractable way forward for developing important malaria management tools

    Simulation of Surface Ozone Pollution in the Central Gulf Coast Region Using WRF/Chem Model: Sensitivity to PBL and Land Surface Physics

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    The fully coupled WRF/Chem (Weather Research and Forecasting/Chemistry) model is used to simulate air quality in the Mississippi Gulf coastal region at a high resolution (4 km) for a moderately severe summer ozone episode between 18 CST 7 and 18 CST 10 June 2006. The model sensitivity is studied for meteorological and gaseous criteria pollutants (O3, NO2) using three Planetary Boundary Layer (PBL) and four land surface model (LSM) schemes and comparison of model results with monitoring station observations. Results indicated that a few combinations of PBL and LSMs could reasonably produce realistic meteorological fields and that the combination of Yonsei University (YSU) PBL and NOAH LSM provides best predictions for winds, temperature, humidity and mixed layer depth in the study region for the period of study. The diurnal range in ozone concentration is better estimated by the YSU PBL in association with either 5-layer or NOAH land surface model. The model seems to underestimate the ozone concentrations in the study domain because of underestimation of temperatures and overestimation of winds. The underestimation of NO2 by model suggests the necessity of examining the emission data in respect of its accurate representation at model resolution. Quantitative analysis for most monitoring stations indicates that the combination of YSU PBL with NOAH LSM provides the best results for various chemical species with minimum BIAS, RMSE, and high correlation values

    W(h)ither the academy? An exploration of the role of university social work in shaping the future of social work in Europe

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    A controversial proposal to pilot the training of child protection social workers through an intensive work-based route in England is being supported and funded by the UK Government. Frontline, the brainchild of a former teacher, locates social work training within local authorities (‘the agency’) rather than university social work departments (‘the academy’) and has stimulated debate amongst social work academics about their role in shaping the direction of the profession. As a contribution to this debate, this paper explores the duality of social work education, which derives its knowledge from both the academic social sciences and the experience of practice within social work agencies. While social work education has traditionally been delivered by the academy, this paper also explores whether the delivery of training in the allied professions of probation and nursing by ‘the agency’ is equally effective. Finally, this paper explores the Helsinki model which achieves a synergy of ‘academy’ and ‘agency’. It suggests that there are alternative models of social work education, practice and research which avoid dichotomies between the ‘academy’ and the ‘agency’ and enable the profession to be shaped by both social work academics and practitioners

    Modulation of SF1 neuron activity coordinately regulates both feeding behaviour and associated emotional states

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    Feeding requires the integration of homeostatic drives with emotional states relevant to food procurement in potentially hostile environments. The ventromedial hypothalamus (VMH) regulates feeding and anxiety, but how these are controlled in a concerted manner remains unclear. Using pharmacogenetic, optogenetic, and calcium imaging approaches with a battery of behavioral assays, we demonstrate that VMH steroidogenic factor 1 (SF1) neurons constitute a nutritionally sensitive switch, modulating the competing motivations of feeding and avoidance of potentially dangerous environments. Acute alteration of SF1 neuronal activity alters food intake via changes in appetite and feeding-related behaviors, including locomotion, exploration, anxiety, and valence. In turn, intrinsic SF1 neuron activity is low during feeding and increases with both feeding termination and stress. Our findings identify SF1 neurons as a key part of the neurocircuitry that controls both feeding and related affective states, giving potential insights into the relationship between disordered eating and stress-associated psychological disorders in humans

    Differential glucocorticoid metabolism in patients with persistent versus resolving inflammatory arthritis

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    Introduction: Impairment in the ability of the inflamed synovium to generate cortisol has been proposed to be a factor in the persistence and severity of inflammatory arthritis. In the inflamed synovium, cortisol is generated from cortisone by the 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) enzyme. The objective of this study was to determine the role of endogenous glucocorticoid metabolism in the development of persistent inflammatory arthritis. Methods: Urine samples were collected from patients with early arthritis (symptoms ≤12 weeks duration) whose final diagnostic outcomes were established after clinical follow-up and from patients with established rheumatoid arthritis (RA). All patients were free of disease-modifying anti-rheumatic drugs at the time of sample collection. Systemic measures of glucocorticoid metabolism were assessed in the urine samples by gas chromatography/mass spectrometry. Clinical data including CRP and ESR were also collected at baseline. Results: Systemic measures of 11β-HSD1 activity were significantly higher in patients with early arthritis whose disease went on to persist, and also in the subgroup of patients with persistent disease who developed RA, when compared with patients whose synovitis resolved over time. We observed a significant positive correlation between systemic 11β-HSD1 activity and ESR/CRP in patients with established RA but not in any of the early arthritis patients group. Conclusions: The present study demonstrates that patients with a new onset of synovitis whose disease subsequently resolved had significantly lower levels of systemic 11β-HSD1 activity when compared with patients whose synovitis developed into RA or other forms of persistent arthritis. Low absolute levels of 11β-HSD1 activity do not therefore appear to be a major contributor to the development of RA and it is possible that a high total body 11β-HSD1 activity during early arthritis may reduce the probability of disease resolution

    Maximal regularity for non-autonomous equations with measurable dependence on time

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    In this paper we study maximal LpL^p-regularity for evolution equations with time-dependent operators AA. We merely assume a measurable dependence on time. In the first part of the paper we present a new sufficient condition for the LpL^p-boundedness of a class of vector-valued singular integrals which does not rely on H\"ormander conditions in the time variable. This is then used to develop an abstract operator-theoretic approach to maximal regularity. The results are applied to the case of mm-th order elliptic operators AA with time and space-dependent coefficients. Here the highest order coefficients are assumed to be measurable in time and continuous in the space variables. This results in an Lp(Lq)L^p(L^q)-theory for such equations for p,q(1,)p,q\in (1, \infty). In the final section we extend a well-posedness result for quasilinear equations to the time-dependent setting. Here we give an example of a nonlinear parabolic PDE to which the result can be applied.Comment: Application to a quasilinear equation added. Accepted for publication in Potential Analysi

    Competitive Performance Effects of Psychological Skill Training for Youth Swimmers

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    This study assessed the effect of two different psychological methods of skills training-self-talk and goal setting-on the swimming performance of youth swimmers. We allocated a convenience sample of club and county level youth swimmers ( N  = 49; M age  = 10.8, SD  = 1.25) to one of the three groups: self-talk, goal setting, or a control group engaged in no systematic psychological method of skills training. The groups were balanced in terms of competitive performance ability, age, and gender. Participants in the experimental conditions (self-talk and goal setting) completed a 5-week psychological skills intervention program and were measured on pre- and post-200-m swimming time in competition. After controlling for level of engagement in the program, analysis of covariance revealed a significant omnibus effect ( p  = .006, η p 2  = .20) with post hoc pairwise comparisons using magnitude-based statistics demonstrating that goal setting had a small positive effect compared with self-talk ( η 2 = .40; ± 0.45). Both self-talk ( η 2 = .50; ±0.48) and goal setting ( η 2 = .71; ±0.4) showed a small and moderate positive effect, respectively, relative to the control group. A social validation check confirmed that the swimmers found the intervention to be relevant, beneficial, and meaningful for improving performance. Psychological skills training may be effective in improving youth swimming performance; specific mechanisms underlying these benefits need further exploration
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