NuSTAR and Swift joint view of neutron star X-ray binary 4U 1728−34: disc reflection in the island and lower banana states

We analyse two simultaneous NuSTAR and Swift data of the Atoll-type neutron star (NS) X-ray binary 4U 1728−34 observed on 2013 October 1 and 3. We infer that the first and the second observations belong to the island state and the lower banana state, respectively. During island state, four type-I X-ray bursts are observed within 60 ks exposure. From the time-resolved spectral analysis of each burst with NuSTAR, the blackbody temperature kT_(bb) are found to vary between 1.3 and 3.0 keV, while the blackbody normalizations (km/10 kpc)^2 vary in the range 20–200, which translates to blackbody radii of 3.5–7.4 km for an assumed distance of 5 kpc. The persistent, joint energy spectra from Swift and NuSTAR for both observations in the energy band 1–79 keV are well described with thermal emission from the NS surface (kT_(bb) ≃ 1–2.5 keV), Comptonized emission of thermal seed photons from the hot boundary layer/corona and the strong reflection component from the accretion disc. We detect a broad iron line in the 5–8 keV band and reflection hump in the 15–30 keV band modelled by the relxill reflection model. Joint spectral fitting constrains the inclination angle of the binary system and inner disc radius to be 22°-40° and (2.0–4.3) × R_(ISCO), respectively. We estimate the magnetic field to be (1.8–6.5) × 108 G. The X-ray luminosity of the source during the island and lower banana states are found to be LX = 1.1 and 1.6 × 10^(37) erg s^(−1), respectively, which correspond to ∼6 per cent and ∼9 per cent of the Eddington luminosity

Crossover of the dimensionality of 3d spin fluctuations in LaCoPO

dc magnetization and 31^P spin lattice relaxation rate in the polycrystalline sample of LaCoPO suggest a spin fluctuation dominated ferromagnetically ordered state. Moreover, NMR data clearly indicate a crossover from 2D to 3D spin fluctuations across T_C. In contrast to isotropic hyperfine field, H_hf at the 31^P site in LaFePO, H_hf is anisotropic in LaCoPO. The data of spin lattice relaxation rate also exhibit anisotropic spin fluctuation. The anisotropy vanishes near T_C

Broad-band X-ray emission and the reality of the broad iron line from the neutron star–white dwarf X-ray binary 4U 1820−30

Broad relativistic iron lines from neutron star X-ray binaries are important probes of the inner accretion disc. The X-ray reflection features can be weakened due to strong magnetic fields or very low iron abundances such as is possible in X-ray binaries with low mass, first generation stars as companions. Here, we investigate the reality of the broad iron line detected earlier from the neutron-star low-mass X-ray binary 4U 1820−30 with a degenerate helium dwarf companion. We perform a comprehensive, systematic broad-band spectral study of the atoll source using Suzaku and simultaneous NuSTAR and Swift observations. We have used different continuum models involving accretion disc emission, thermal blackbody and thermal Comptonization of either disc or blackbody photons. The Suzaku data show positive and negative residuals in the region of Fe K band. These features are well described by two absorption edges at 7.67 ± 0.14 keV and 6.93 ± 0.07 keV or partial covering photoionized absorption or by blurred reflection. Though, the simultaneous Swift and NuSTAR data do not clearly reveal the emission or absorption features, the data are consistent with the presence of either absorption or emission features. Thus, the absorption based models provide an alternative to the broad iron line or reflection model. The absorption features may arise in winds from the inner accretion disc. The broad-band spectra appear to disfavour continuum models in which the blackbody emission from the neutron-star surface provides the seed photons for thermal Comptonization. Our results suggest emission from a thin accretion disc (kT_(disc) ∼ 1 keV), Comptonization of disc photons in a boundary layer most likely covering a large fraction of the neutron-star surface and innermost parts of the accretion disc, and blackbody emission (kT_(bb) ∼ 2 keV) from the polar regions

Challenges and opportunities in the implementation of an antimicrobial stewardship program in Nepal

Antimicrobial resistance (AMR) continues to be a serious global public issue. Unnecessary and inappropriate use of antimicrobials has been identified as a major contributing factor for AMR. Implementation of antimicrobial stewardship programs (ASPs) is valued as a key strategy to combat AMR. Although ASP is a key intervention to improve appropriate use of antibiotics, there is limited experience and research to describe its implementation in low-income countries such as Nepal. Grande International Hospital (GIH) is the first health organization in Nepal to implement and sustain a multidisciplinary ASP and infection control program. Challenges faced in implementing ASP include lack of acceptance from physicians, lack of knowledge regarding antibiotic prescribing, lack of staff for ASP activities, limitations in diagnostic testing to inform ASP, and limitations in antibiotic choice due to antibiotic unavailability. Our ASP includes the following components: an ASP committee, an antibiotic prescribing reference guide with dosage recommendations, inpatient formulary restriction system, educational outreach and programming for physicians and other stakeholders, and periodic review and revision of the program and reference guide. The ASP provided opportunities to address several knowledge gaps across our healthcare institution including improved knowledge and competency regarding rational use of antibiotics, access to quality medicines and better care to patients. It is our hope that, by describing the challenges and opportunities we experienced while implementing our ASP, we can support and encourage other institutions to adapt and implement ASPs in Nepal and other resource-limited settings

Genetic, Pathophysiological and Clinical Aspects of Nephrocalcinosis

Nephrocalcinosis describes the ectopic deposition of calcium salts in the kidney parenchyma. Nephrocalcinosis can result from a number of acquired causes, but also an even greater number of genetic diseases, predominantly renal, but also extra-renal. Here we provide a review of the genetic causes of nephrocalcinosis, along with putative mechanisms, illustrated by human and animal data

The curious activity in the nucleus of NGC 4151: jet interaction causing variability?

A key characteristic of many active galactic nuclei (AGNs) is their variability, but its origin is poorly understood, especially in the radio domain. Williams et al. (2017) reported a ∼50 per cent increase in peak flux density of the AGN in the Seyfert galaxy NGC 4151 at 1.5 GHz with the e-MERLIN array. We present new high-resolution e-MERLIN observations at 5 GHz and compare these to archival MERLIN observations to investigate the reported variability. Our new observations allow us to probe the nuclear region at a factor three times higher resolution than the previous e-MERLIN study. We separate the core component, C4, into three separate components: C4W, C4E, and X. The AGN is thought to reside in component C4W, but this component has remained constant between epochs within uncertainties. However, we find that the Eastern-most component, C4E, has increased in peak flux density from 19.35 ± 1.10 to 37.09 ± 1.86 mJy beam−1, representing an 8.2σ increase on the MERLIN observations. We attribute this peak flux density increase to continue interaction between the jet and the emission line region (ELR), observed for the first time in a low-luminosity AGNs such as NGC 4151. We identify discrete resolved components at 5 GHz along the jet axis, which we interpret as areas of jet–ELR interaction