30,388 research outputs found

    Theoretical analysis of the atmospheres of CP stars. Effects of the individual abundance patterns

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    Context. See abstract in the paper. Aims. See abstract in the paper. Methods. See abstract in the paper. Results. We present a homogeneous study of model atmosphere temperature structure, energy distribution, photometric indices in the uvbybeta and Delta_a systems, hydrogen line profiles, and the abundance determination procedure as it applies to CP stars. In particular, we found that Si, Cr and Fe are the main elements to influence model atmospheres of CP stars, and thus to be considered in order to assess the adequacy of model atmospheres with scaled solar abundances in application to CP stars. We provide a theoretical explanation of the robust property of the Delta_a photometric system to recognize CP stars with peculiar Fe content. Also, the results of our numerical tests using model atmospheres with one or several elements overabundant (Si and Fe by +1 dex, Cr by +2 dex) suggest that the uncertainty of abundance analysis in the atmospheres of CP stars using models with scaled abundances is less than plus/minus 0.25 dex. If the same homogeneous models are used for the abundance stratification analysis then we find that the uncertainty of the value of the vertical abundance gradient is within an 0.4 dex error bar. Conclusions. Model atmospheres with individual abundance patterns should be used in order to match the actual anomalies of CP stars and minimize analysis errors.Comment: 18 pages, 9 figure

    WavePacket: A Matlab package for numerical quantum dynamics. III: Quantum-classical simulations and surface hopping trajectories

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    WavePacket is an open-source program package for numerical simulations in quantum dynamics. Building on the previous Part I [Comp. Phys. Comm. 213, 223-234 (2017)] and Part II [Comp. Phys. Comm. 228, 229-244 (2018)] which dealt with quantum dynamics of closed and open systems, respectively, the present Part III adds fully classical and mixed quantum-classical propagations to WavePacket. In those simulations classical phase-space densities are sampled by trajectories which follow (diabatic or adiabatic) potential energy surfaces. In the vicinity of (genuine or avoided) intersections of those surfaces trajectories may switch between surfaces. To model these transitions, two classes of stochastic algorithms have been implemented: (1) J. C. Tully's fewest switches surface hopping and (2) Landau-Zener based single switch surface hopping. The latter one offers the advantage of being based on adiabatic energy gaps only, thus not requiring non-adiabatic coupling information any more. The present work describes the MATLAB version of WavePacket 6.0.2 which is essentially an object-oriented rewrite of previous versions, allowing to perform fully classical, quantum-classical and quantum-mechanical simulations on an equal footing, i.e., for the same physical system described by the same WavePacket input. The software package is hosted and further developed at the Sourceforge platform, where also extensive Wiki-documentation as well as numerous worked-out demonstration examples with animated graphics are available

    An examination of service user satisfaction in forensic mental health settings

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    High levels of service user satisfaction are viewed as a reliable indicator of a service providing good care and treatment. There has been limited research looking into levels of satisfaction in forensic mental health settings with most work focused on staff satisfaction in these settings. This study examined service users' levels of satisfaction with a forensic mental health service in the UK. The service covered two sites; one a purpose-built secure unit and the other based in an old cottage hospital. Thirty-nine in-patients completed a 60-item validated forensic satisfaction scale. The scale measured seven domains of satisfaction as well as reporting an overall satisfaction score. The results indicated the service users were reasonably satisfied with the care and treatment they received. The domains of rehabilitation, safety, staff interaction and overall care showed the highest level of satisfaction. The high rehabilitation satisfaction score demonstrated the importance of meaningful activities for users accessing forensic services and may have been influenced by the security measures on the wards. The high safety domain score indicated respondents felt safe and secure within the wards and likely to be influenced by positive interpersonal interactions. Good staff interaction was also an important factor in helping service users feel safe on the wards. These interactions are likely to be associated with the longer periods of admission in secure services allowing therapeutic relationships to develop. Financial advice/support was the one domain that recorded negative satisfaction levels. Financial literacy training may help develop money management skills

    Stellar model atmospheres with magnetic line blanketing. III. The role of magnetic field inclination

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    Context. See abstract in the paper. Aims. In the last paper of this series we study the effects of the magnetic field, varying its strength and orientation, on the model atmosphere structure, the energy distribution, photometric colors and the hydrogen Balmer line profiles. We compare with the previous results for an isotropic case in order to understand whether there is a clear relation between the value of the magnetic field angle and model changes, and to study how important the additional orientational information is. Also, we examine the probable explanation of the visual flux depressions of the magnetic chemically peculiar stars in the context of this work. Methods. We calculated one more grid of the model atmospheres of magnetic A and B stars for different effective temperatures (Teff=8000K, 11000K, 15000K), magnetic field strengths (B=0, 5, 10, 40 kG) and various angles of the magnetic field (Omega=0-90 degr) with respect to the atmosphere plane. We used the LLmodels code which implements a direct method for line opacity calculation, anomalous Zeeman splitting of spectral lines, and polarized radiation transfer. Results. We have not found significant changes in model atmosphere structure, photometric and spectroscopic observables or profiles of hydrogen Balmer lines as we vary the magnetic field inclination angle Omega. The strength of the magnetic field plays the main role in magnetic line blanketing. We show that the magnetic field has a clear relation to the visual flux depressions of the magnetic CP stars. Conclusions. See abstract in the paper.Comment: 10 pages, 5 figure

    Anomalous thermal expansion of Sb2_2Te3_3 topological insulator

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    We have investigated the temperature dependence of the linear thermal expansion along the hexagonal c axis (ΔL\Delta L), in-plane resistivity (ρ\rho), and specific heat (CpC_p) of the topological insulator Sb2_2Te3_3 single crystal. ΔL\Delta L exhibits a clear anomaly in the temperature region 204-236 K. The coefficient of linear thermal expansion α\alpha decreases rapidly above 204 K, passes through a deep minimum at around 225 K and then increases abruptly in the region 225-236 K. α\alpha is negative in the interval 221-228 K. The temperature dependence of both α\alpha and CpC_p can be described well by the Debye model from 2 to 290 K, excluding the region around the anomaly in α\alpha

    Stellar model atmospheres with magnetic line blanketing. II. Introduction of polarized radiative transfer

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    The technique of model atmosphere calculation for magnetic Ap and Bp stars with polarized radiative transfer and magnetic line blanketing is presented. A grid of model atmospheres of A and B stars are computed. These calculations are based on direct treatment of the opacities due to the bound-bound transitions that ensures an accurate and detailed description of the line absorption and anomalous Zeeman splitting. The set of model atmospheres was calculated for the field strengths between 1 and 40 kG. The high-resolution energy distribution, photometric colors and the hydrogen Balmer line profiles are computed for magnetic stars with different metallicities and are compared to those of non-magnetic reference models and to the previous paper of this series. The results of modelling confirmed the main outcomes of the previous study: energy redistribution from UV to the visual region and flux depression at 5200A. However, we found that effects of enhanced line blanketing when transfer for polarized radiation takes place are smaller in comparison to those obtained in our first paper where polarized radiative transfer was neglected. Also we found that the peculiar photometric parameter delta_a is not able to clearly distinguish stellar atmospheres with abundances other than solar, and is less sensitive than delta(V_1-G) or Z to a magnetic field for low effective temperature (Teff=8000K). Moreover we found that the back determination of the fundamental stellar atmosphere parameters using synthetic Stromgren photometry does not result in significant errors.Comment: 12 pages, 6 figures. The final version, Sect. 3.4 revised, typos and mistakes correcte

    A study on few biochemical parameters of clinically suspected and laboratory confirmed Leptospirosis cases

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    A study on biochemical parameters in clinically suspected and laboratory- confirmed leptospirosis cases was conducted in the Union Territory of Dadra and Nagar Haveli. Out of 50 clinically suspected samples of leptospirosis, 38% were positive from both ELISA IgM and rapid card test. In the present study, liver markers such as bilirubin, Serum Glutamate Oxalo acetic Transaminase (SGOT) and Serum Glutamate Pyruvic Transaminase (SGPT) encountered elevation 68%, 100% and 89% respectively in leptospiosis positive patent while 89% and 48 %of positive patients showed elevation in kidney marker, creatinine and blood urea. On the basis of liver and renal functions, a hospital can develop its own clinical algorithm to suspect the case of leptospirosis
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