124 research outputs found
The effect of thermal winds on the outbursts evolution of LMXB systems
Theoretical models of accretion discs and observational data indicate that
the X-ray emission from the inner parts of an accretion disc can irradiate its
outer regions and induce a thermal wind, which carries away the mass and
angular momentum from the disc. Our aim is to investigate the influence of the
thermal wind on the outburst light curves of black hole X-ray binary systems.
We carry out numerical simulations of a non-stationary disc accretion with wind
using upgraded open code freddi. We assume that the wind launches only from the
ionised part of the disc and may turn off if the latter shrinks fast enough.
Our estimates of the viscosity parameter are shifted downward compared
to a scenario without a wind. Generally, correction of depends on the
spectral hardness of central X-rays and the disc outer radius, but unlikely to
exceed a factor of 10 in the case of a black hole low-mass X-ray binary (BH
LMXB). We fit 2002 outburst of BH LMXB 4U 1543-47 taking into account the
thermal wind. The mass loss in the thermal wind is of order of the accretion
rate on the central object at the peak of the outburst. New estimate of the
viscosity parameter for the accretion disc in this system is about two
times lower than the previous one. Additionally, we calculate evolution of the
number of hydrogen atoms towards 4U 1543-47 due to the thermal wind from the
hot disc.Comment: 19 pages, 22 figures, accepted for publication in MNRA
Piezoelectric, ferroelectric, optoelectronic and photo-catalytic phenomena from defect levels in hydroxyapatite by first-principles
The authors thank the Russian Foundation for Basic Researches (RFBR grant 19-01-00519 A) and to the Fundação para a Ciência e a Tecnologia (FCT) through project UID/CTM/50025/2013
Measurement of the Cross Section Asymmetry of the Reaction gp-->pi0p in the Resonance Energy Region Eg = 0.5 - 1.1 GeV
The cross section asymmetry Sigma has been measured for the photoproduction
of pi0-mesons off protons, using polarized photons in the energy range Eg = 0.5
- 1.1 GeV. The CM angular coverage is Theta = 85 - 125 deg with energy and
angle steps of 25 MeV and 5 deg, respectively. The obtained Sigma data, which
cover the second and third resonance regions, are compared with existing
experimental data and recent phenomenological analyses. The influence of these
measurements on such analyses is also considered
The influence of the dechanneling process on the photon emission by an ultra-relativistc positron channeling in a periodically bent crystal
We investigate, both analytically and numerically, the influence of the
dechanneling process on the parameters of undulator radiation generated by
ultra-relativistic positron channelling along a crystal plane, which is
periodically bent. The bending might be due either to the propagation of a
transverse acoustic wave through the crystal, or due to the static strain as it
occurs in superlattices. In either case the periodically bent crystal serves as
an undulator which allows to generate X-ray and gamma-radiation.
We propose the scheme for accurate quantitative treatment of the radiation in
presence of the dechanneling. The scheme includes (i) the analytic expression
for spectral-angular distribution which contains, as a parameter, the
dechanneling length, (ii) the simulation procedure of the dechanneling process
of a positron in periodically bent crystals. Using these we calculate the
dechanneling lengths of 5 GeV positrons channeling in Si, Ge and W crystals,
and the spectral-angular and spectral distributions of the undulator over broad
ranges of the photons. The calculations are performed for various parameters of
the channel bending.Comment: published in J. Phys. G: Nucl. Part. Phys. 27 (2001) 95-125,
http://www.iop.or
Modern aproaches to diabetic macular edema diagnosticks
Diabetic macular edema (DME) continues to be an important problem of modern ophthalmology and endocrinology. The risk of edema is higher in patients with type 2 diabetes. Thus, this is the main cause of irreversible vision loss in these patients. DME is one of the prognostically unfavorable and difficult to treat manifestations of diabetic retinopathy. As the main cause of vision loss in diabetic patients, diabetic macular edema is often not diagnosed immediately, which causes difficulties in the treatment of pathology. Thus, early diagnosis and timely treatment of this disease is the key to successfully counteract the uncontrolled decline in the patient’s visual functions. In this article, the team of authors highlighted the possibilities of informative instrumental research methods available in the Arsenal of modern ophthalmological services. Based on the analysis of modern literature, the main principles of these diagnostic methods were indicated, their key capabilities and limitations compared to each other were highlighted. Knowledge of these characteristics is, in our opinion, an integral and most important tool in the Arsenal of a practicing ophthalmologist who supervises patients with this pathology
Polarization switching and piezoresponse in PVDF/P(VDF-TrFE) ferroelectric films and multifunctional G/GO composites
Such composites can serve as a multifunctional molecular unit. Further models are in progress. The work is supported by RFBR grants # 15-01-04924, # 16-51-53017 and RSF grant #16-19-10112
Updated resonance photo-decay amplitudes to 2 GeV
We present the results of an energy-dependent and set of single-energy
partial-wave analyses of single-pion photoproduction data. These analyses
extend from threshold to 2 GeV in the laboratory photon energy, and update our
previous analyses to 1.8 GeV. Photo-decay amplitudes are extracted for the
baryon resonances within this energy range. We consider two photoproduction sum
rules and the contributions of two additional resonance candidates found in our
most recent analysis of elastic scattering data. Comparisons are made
with previous analyses.Comment: Revtex, 26 pages, 3 figures. Postscript figures available from
ftp://clsaid.phys.vt.edu/pub/pr or indirectly from
http://clsaid.phys.vt.edu/~CAPS
P-wave excited baryons from pion- and photo-induced hyperon production
We report evidence for , , ,
, , and , and find
indications that might have a companion state at 1970\,MeV. The
controversial is not seen. The evidence is derived from a
study of data on pion- and photo-induced hyperon production, but other data are
included as well. Most of the resonances reported here were found in the
Karlsruhe-Helsinki (KH84) and the Carnegie-Mellon (CM) analyses but were
challenged recently by the Data Analysis Center at GWU. Our analysis is
constrained by the energy independent scattering amplitudes from either
KH84 or GWU. The two amplitudes from KH84 or GWU, respectively, lead to
slightly different branching ratios of contributing resonances but the
debated resonances are required in both series of fits.Comment: 22 pages, 28 figures. Some additional sets of data are adde
Integrable Ladder t-J Model with Staggered Shift of the Spectral Parameter
The generalization of the Yang-Baxter equations (YBE) in the presence of Z_2
grading along both chain and time directions is presented and an integrable
model of t-J type with staggered disposition along a chain of shifts of the
spectral parameter is constructed. The Hamiltonian of the model is computed in
fermionic formulation. It involves three neighbour site interactions and
therefore can be considered as a zig-zag ladder model. The Algebraic Bethe
Ansatz technique is applied and the eigenstates, along with eigenvalues of the
transfer matrix of the model are found. In the thermodynamic limit, the lowest
energy of the model is formed by the quarter filling of the states by fermions
instead of usual half filling.Comment: Latex2e with amsfonts package; 16 page
Динамика выживаемости больных муковисцидозом в Москве и Московской области за периоды 1992–2001 и 2002–2011 гг.
Summary. The aim of this study was to evaluate changes in survival of patients with cystic fibrosis (CF) in Moscow and Moscow region and to determine factors influencing the survival. We analyzed outpatient medical records of patients followed-up in Moscow CF centers by the 1st of January, 2002, and by the 1st of January, 2012.Median survival for 2002–2012 was 37.2 years; this was significantly higher that the similar value for the previous decade (25.9 years). A total number of CF patients was more than doubled due to increased survival and improved diagnosis of the disease.Improved survival was due to improved work of CF centers and to implementation of effective medications, primarily dornase alfa (Pulmozyme) and some inhaled and systemic antibiotics and macrolides in subinhibitory concentrations, in routine clinical practice. Gram-negative infection, especially Burkholderia cepacia, was shown to decrease survival in CF patients in contrary to "mild" mutations that are better prognostic factors.Резюме. Целью работы явилось определение динамики числа и выживаемости больных муковисцидозом (МВ) в Москве и Московской области, а также определение факторов, влияющих на выживаемость. Были проанализированы амбулаторные карты больных, состоящих на учете в московских центрах муковисцидоза на 01.01.2002 и 01.01.2012.Медиана выживаемости больных за периоды 2002–2011 гг. составила 37,2 года, что достоверно выше, чем аналогичный показатель за предыдущее 10-летие – 25,9 года. Отмечено более чем 2-кратное увеличение общего количества больных, обусловленное ростом выживаемости и улучшением диагностики.Увеличение выживаемости обусловлено оптимизацией работы центров МВ и началом рутинного применения различных эффективных медикаментозных препаратов, прежде всего дорназы альфа (Пульмозим), а также некоторых ингаляционных и системных антибиотиков, макролидов в субингибирующих концентрациях. Показано, что инфицирование грамотрицательной инфекцией, особенно Burkholderia cepacia, снижает выживаемость пациентов с МВ, а наличие "мягкого" генотипа является более благоприятным прогностическим фактором
- …