Cyclotron resonant scattering feature simulations. I. Thermally averaged cyclotron scattering cross sections, mean free photon-path tables, and electron momentum sampling

Electron cyclotron resonant scattering features (CRSFs) are observed as absorption-like lines in the spectra of X-ray pulsars. A significant fraction of the computing time for Monte Carlo simulations of these quantum mechanical features is spent on the calculation of the mean free path for each individual photon before scattering, since it involves a complex numerical integration over the scattering cross section and the (thermal) velocity distribution of the scattering electrons. We aim to numerically calculate interpolation tables which can be used in CRSF simulations to sample the mean free path of the scattering photon and the momentum of the scattering electron. The tables also contain all the information required for sampling the scattering electron's final spin. The tables were calculated using an adaptive Simpson integration scheme. The energy and angle grids were refined until a prescribed accuracy is reached. The tables are used by our simulation code to produce artificial CRSF spectra. The electron momenta sampled during these simulations were analyzed and justified using theoretically determined boundaries. We present a complete set of tables suited for mean free path calculations of Monte Carlo simulations of the cyclotron scattering process for conditions expected in typical X-ray pulsar accretion columns (0.01<B/B_{crit}<=0.12, where B_{crit}=4.413x10^{13} G and 3keV<=kT<15keV). The sampling of the tables is chosen such that the results have an estimated relative error of at most 1/15 for all points in the grid. The tables are available online at http://www.sternwarte.uni-erlangen.de/research/cyclo.Comment: A&A, in pres

Be-Phenomenon in Neutron Star X-ray Binaries

In this work we provide a brief insight into two aspects of Be/X-ray binaries, which are probably involved in production of X-ray outbursts: the evolution of the Be star disk, in particular of its size, and the binary geometry which drives gravitational interaction. Simultaneous X-ray and optical data will aid our investigation of the evolution of Be stars in binaries and the X-ray outburst mechanism

Ab-initio design of perovskite alloys with predetermined properties: The case of Pb(Sc_{0.5} Nb_{0.5})O_{3}

A first-principles derived approach is combined with the inverse Monte Carlo technique to determine the atomic orderings leading to prefixed properties in Pb(Sc_{0.5}Nb_{0.5})O_{3} perovskite alloy. We find that some arrangements between Sc and Nb atoms result in drastic changes with respect to the disordered material, including ground states of new symmetries, large enhancement of electromechanical responses, and considerable shift of the Curie temperature. We discuss the microscopic mechanisms responsible for these unusual effects.Comment: 5 pages with 2 postscript figures embedde

NuSTAR observation of GRO J1744-28 at low mass accretion rate

We present the spectral analysis of the LMXB GRO J1744-28 using $\sim$29 ks of NuSTAR data taken in 2017 February at a low luminosity of $3.2\times 10^{36}$ erg/s (3-50 keV). The continuum spectrum is modeled with an absorbed power-law with exponential cut-off, and an additional iron line component. We find no obvious indications for a CRSF and therefore perform a detailed cyclotron line search using statistical methods on the pulse phase-averaged as well as phase-resolved spectra. The previously detected Type II X-ray bursts are absent. Clear pulsations at a period of 2.141124(9) Hz are detected. The pulse profile shows an indication of a secondary peak, which was not seen at higher flux. The 4$\sigma$ upper limit for the strength of a CRSF in the 3-20 keV band is 0.07 keV, lower than the strength of the line found at higher luminosity. The detection of pulsations shows that the source did not enter the "propeller" regime, even though the source flux of $4.15\times 10^{-10}$ erg/cm$^{2}$/s was almost one order of magnitude below the threshold for the propeller regime claimed in previous studies on this source. The transition into the propeller regime in GRO J1744-28 must therefore be below a luminosity of $3.2\times 10^{36}$ erg/s, which implies a surface magnetic field $\lesssim 2.9\times 10^{11}$ G and mass accretion rate $\lesssim 1.7\times 10^{16}$ g/s. A change of the CRSF depth as function of luminosity is not unexpected and has been observed in other sources. This result possibly implies a change in emission geometry as function of mass accretion rate to reduce the depth of the line below our detection limit

TRIPS implementation and secondary pharmaceutical patenting in Brazil and India

This article compares national approaches toward secondary pharmaceutical patents. Because secondary patents can extend periods of exclusivity and delay generic competition, they can raise prices and reduce access to medicines. Little is known about what measures countries have enacted policies to address applications for secondary pharmaceutical patents, how they function, and whether, in practice, these measures limit secondary patents. We analyze the cases of India and Brazil. We assemble data on pharmaceutical patent applications filed in the two countries, code each application to identify which constitute secondary applications, and examine outcomes for each application in both countries. The data indicate that Brazil is less likely to grant applications than India, but in both countries the measures designed to limit secondary patents are having little direct effect. This suggests, on the one hand, that critics of these policies, such as the transnational pharmaceutical sector and foreign governments, may be more worried than they should be. On the other hand, champions of the policies, such as NGOs and international organizations, may have cause for concern that laws on the books are not having the expected impact on patent outcomes in practice. Our findings also suggest that, at the drug level, the effects of countries’ approaches toward secondary patents need to be understood in the context of their broader approaches toward TRIPS implementation, including when and how they introduced pharmaceutical patents in the 1990s and 2000s

A study of patent thickets

Report analysing whether entry of UK enterprises into patenting in a technology area is affected by patent thickets in the technology area

A constant Cyclotron Line Energy in 4U 0115+634

We present a study of RXTE and INTEGRAL spectra of the transient 3.6 s X-ray pulsar 4U 0115+634 taken during a giant outburst in 2008 March/April. The spectra can be almost equally well modeled by two different semi-empirical continuum models, modified by an Fe Kα fluorescence line, interstellar absorption, and cyclotron resonance scattering features (CRSFs) located at ∼10.7, 21.8, 35.5, 46.7, and 59.7 keV. One of these two models, the so called NPEX model, leads to an anticorrelation between the centroid energy of the fundamental CRSF E_0 and the X-ray flux F_X, in agreement with previous works. The other model, consisting of a simple exponentially cutoff power law modified by a Gaussian emission feature around 10 keV, however, leads to a constant value for E_0 for the observed fluxes and a comparatively narrow line shape. We show that the cyclotron line model component resulting from the NPEX fits rather contribute to the broadband continuum model. We conclude that the previously reported anticorrelation is probably due to an artifact of the particular modeling of the continuum

Lung function and atherosclerosis: a cross-sectional study of multimorbidity in rural Uganda

Background: Chronic obstructive pulmonary disease (COPD) is a leading cause of global mortality. In high-income settings, the presence of cardiovascular disease among people with COPD increases mortality and complicates longitudinal disease management. An estimated 26 million people are living with COPD in sub-Saharan Africa, where risk factors for co-occurring pulmonary and cardiovascular disease may differ from high-income settings but remain uncharacterized. As non-communicable diseases have become the leading cause of death in sub-Saharan Africa, defining multimorbidity in this setting is critical to inform the required scale-up of existing healthcare infrastructure. Methods: We measured lung function and carotid intima media thickness (cIMT) among participants in the UGANDAC Study. Study participants were over 40 years old and equally divided into people living with HIV (PLWH) and an age- and sex-similar, HIV-uninfected control population. We fit multivariable linear regression models to characterize the relationship between lung function (forced expiratory volume in one second, FEV1) and pre-clinical atherosclerosis (cIMT), and evaluated for effect modification by age, sex, smoking history, HIV, and socioeconomic status. Results: Of 265 participants, median age was 52 years, 125 (47%) were women, and 140 (53%) were PLWH. Most participants who met criteria for COPD were PLWH (13/17, 76%). Median cIMT was 0.67 mm (IQR: 0.60 to 0.74), which did not differ by HIV serostatus. In models adjusted for age, sex, socioeconomic status, smoking, and HIV, lower FEV1 was associated with increased cIMT (β = 0.006 per 200 mL FEV1 decrease; 95% CI 0.002 to 0.011, p = 0.01). There was no evidence that age, sex, HIV serostatus, smoking, or socioeconomic status modified the relationship between FEV1 and cIMT. Conclusions: Impaired lung function was associated with increased cIMT, a measure of pre-clinical atherosclerosis, among adults with and without HIV in rural Uganda. Future work should explore how co-occurring lung and cardiovascular disease might share risk factors and contribute to health outcomes in sub-Saharan Africa

The integration of social concerns into electricity power planning : a combined delphi and AHP approach

The increasing acceptance of the principle of sustainable development has been a major driving force towards new approaches to energy planning. This is a complex process involving multiple and conflicting objectives, in which many agents were able to influence decisions. The integration of environmental, social and economic issues in decision making, although fundamental, is not an easy task, and tradeoffsmust be made. The increasing importance of social aspects adds additional complexity to the traditional models that must now deal with variables recognizably difficult to measure in a quantitative scale. This study explores the issue of the social impact, as a fundamental aspect of the electricity planning process, aiming to give a measurable interpretation of the expected social impact of future electricity scenarios. A structured methodology, based on a combination of the Analytic Hierarchy Process and Delphi process, is proposed. The methodology is applied for the social evaluation of future electricity scenarios in Portugal, resulting in the elicitation and assignment of average social impact values for these scenarios. The proposed tool offers guidance to decision makers and presents a clear path to explicitl

Early intervention to promote oral feeding in patients with intracerebral hemorrhage: a retrospective cohort study

<p>Abstract</p> <p>Background</p> <p>Stroke is a major cause of dysphagia, but little is known about when and how dysphagic patients should be fed and treated after an acute stroke. The purpose of this study is to establish the feasibility, risks and clinical outcomes of early intensive oral care and a new speech and language therapist/nurse led structured policy for oral feeding in patients with an acute intracerebral hemorrhage (ICH).</p> <p>Methods</p> <p>A total of 219 patients with spontaneous ICH who were admitted to our institution from 2004 to 2007 were retrospectively analyzed. An early intervention program for oral feeding, which consisted of intensive oral care and early behavioral interventions, was introduced from April 2005 and fully operational by January 2006. Outcomes were compared between an early intervention group of 129 patients recruited after January 2006 and a historical control group of 90 patients recruited between January 2004 and March 2005. A logistic regression technique was used to adjust for baseline differences between the groups. To analyze time to attain oral feeding, the Kaplan-Meier method and Cox proportional hazard model were used.</p> <p>Results</p> <p>The proportion of patients who could tolerate oral feeding was significantly higher in the early intervention group compared with the control group (112/129 (86.8%) vs. 61/90 (67.8%); odds ratio 3.13, 95% CI, 1.59-6.15; P < 0.001). After adjusting for baseline imbalances, the odds ratio was 4.42 (95% CI, 1.81-10.8; P = 0.001). The incidence of chest infection was lower in the early intervention group compared with the control group (27/129 (20.9%) vs. 32/90 (35.6%); odds ratio 0.48, 95% CI, 0.26-0.88; P = 0.016). A log-rank test found a significant difference in nutritional supplementation-free survival between the two groups (hazard ratio 1.94, 95% CI, 1.46-2.71; P < 0.001).</p> <p>Conclusions</p> <p>Our data suggest that the techniques can be used safely and possibly with enough benefit to justify a randomized controlled trial. Further investigation is needed to solve the eating problems that are associated with patients recovering from a severe stroke.</p