30,388 research outputs found
Theoretical analysis of the atmospheres of CP stars. Effects of the individual abundance patterns
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
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
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
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 SbTe topological insulator
We have investigated the temperature dependence of the linear thermal
expansion along the hexagonal c axis (), in-plane resistivity
(), and specific heat () of the topological insulator SbTe
single crystal. exhibits a clear anomaly in the temperature region
204-236 K. The coefficient of linear thermal expansion decreases
rapidly above 204 K, passes through a deep minimum at around 225 K and then
increases abruptly in the region 225-236 K. is negative in the
interval 221-228 K. The temperature dependence of both and can
be described well by the Debye model from 2 to 290 K, excluding the region
around the anomaly in
Stellar model atmospheres with magnetic line blanketing. II. Introduction of polarized radiative transfer
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
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The association of neutrophil-lymphocyte ratio and lymphocyte-monocyte ratio with 3-month clinical outcome after mechanical thrombectomy following stroke
Background and aim
Neutrophil-lymphocyte ratio (NLR) and lymphocyte-monocyte ratio (LMR) are associated with clinical outcomes in malignancy, cardiovascular disease and stroke. Here we investigate their association with outcome after acute ischaemic stroke treated by mechanical thrombectomy (MT).
Methods
Patients were selected using audit data for MT for acute anterior circulation ischaemic stroke at a UK centre from May 2016–July 2017. Clinical and laboratory data including neutrophil, lymphocyte and monocyte count tested before and 24 h after MT were collected. Poor functional outcome was defined as modified Rankin Scale (mRS) of 3–6 at 3 months. Multivariable logistic regression analyses were performed to explore the relationship of NLR and LMR with functional outcome.
Results
One hundred twenty-one patients (mean age 66.4 ± 16.7, 52% female) were included. Higher NLR (adjusted OR 0.022, 95% CI, 0.009–0.34, p = 0.001) and lower LMR (adjusted OR − 0.093, 95% CI (− 0.175)−(− 0.012), p = 0.025) at 24-h post-MT were significantly associated with poorer functional outcome when controlling for age, baseline NIHSS score, infarct size, presence of good collateral supply, recanalisation and symptomatic intracranial haemorrhage on multivariate logistic regression. Admission NLR or LMR were not significant predictors of mRS at 3 months. The optimal cut-off values of NLR and LMR at 24-h post-MT that best discriminated poor outcome were 5.5 (80% sensitivity and 60% specificity) and 2.0 (80% sensitivity and 50% specificity), respectively on receiver operating characteristic curve analysis.
Conclusion
NLR and LMR tested at 24 h after ictus or intervention may predict 3-month functional outcome
A study on few biochemical parameters of clinically suspected and laboratory confirmed Leptospirosis cases
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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