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The impact ionization rate of electrons and holes in (0001)-oriented 4H-SiC has been measured under steady oblique magnetic field and hence, the influence of magnetic field on the breakdown characteristics of 4H-SiC diodes has been investigated. A set of three diodes having p + –n–n + structure and another set of three diodes having n + –p–p + structure have been grown on (0001)-oriented n + and p + 4H-SiC substrates using chemical vapor deposition (CVD) technique with different epitaxial layer thicknesses for carrying out the measurements within the electric field range of 2.5 × 10 8 –4.0 × 10 8  V m −1 . The ionization rate data are extracted from the photomultiplication measurements using ultra-violet light source of 260-nm wavelength. The ionization rates are found to be decreased with the increase of the magnetic field strength, especially at low electric fields; this decrement is found to be more pronounced in the ionization rate of electrons than the same of holes. A theoretical model developed by the authors is used to calculate the breakdown voltage of the 4H-SiC diodes. The numerical results are compared with the experimentally measured breakdown characteristics and those are found to be in good agreement within the externally applied magnetic field strengths of 0–1500 Gauss. Breakdown voltage of a diode is found to be increased due to the presence of magnetic field; the maximum values of these said increments are found to be around 5% and 2.6% in p + –n–n + and n + –p–p + diodes, respectively. Better magnetic field sensitivity is observed in the diodes having broader epitaxial layer widths.

Two-dimensional large-signal and noise simulations are used to study the terahertz (THz) performance of Gallium Nitride (GaN) avalanche transit time source (ATT) source. A comprehensive model of parasitic series resistance has been developed by which the effect of series resistance on the large-signal and noise performance of the 1.0 THz GaN ATT source has been investigated; the proposed model is based on time varying depletion width modulation under large-signal oscillating condition. Significant amount of deterioration in power output and efficiency have been observed due to the existence of series resistance of the device. On the other hand, the realization of the optimized structure and doping profile as per the theoretical design is a tricky job by considering the state-of-the-art GaN fabrication technology. Especially, achieving the absolute values of epitaxial doping densities is almost an unrealistic task. Therefore, it is very important to acquire the knowledge about how much extent the power output, series resistance and noise measure of the source are affected due to the change in doping level of both n- and p-layers. In the present study, the sensitivities of the above-mentioned parameters with respect to the change in the doping densities of n- and p-layers have been investigated.

We report the discovery of a young pulsar associated with the supernova remnant G21.5–0.9, using the Giant Metrewave Radio Telescope (GMRT) located near Pune, India. Discovered at a frequency of 610 MHz, PSR J1833–1034 has a period of 61.86 ms and a period derivative of 2.0 × 10-13, making it similar to other known young pulsars. The characteristic age of the pulsar is ≈ 4900 yrs, somewhat higher than estimates for the age of the remnant, but not incompatible with it. The pulsar has a spin-down luminosity of 3.3 × 1037 erg s-1, which is the second highest amongst all the known galactic pulsars.

Background. Modified vaccinia Ankara (MVA-BN, IMVAMUNE) is emerging as a primary immunogen and as a delivery system to treat or prevent a wide range of diseases. Defining the safety and immunogenicity of MVA-BN in key populations is therefore important. Methods. We performed a dose-escalation study of MVA-BN administered subcutaneously in 2 doses, one on day 0 and another on day 28. Twenty-four hematopoietic stem cell transplant recipients were enrolled sequentially into the study, and vaccine or placebo was administered under a randomized, double-blind allocation. Ten subjects received vaccine containing 10 7 median tissue culture infective doses (TCID 50 ) of MVA-BN, 10 subjects received vaccine containing 10 8 TCID 50 of MVA-BN, and 4 subjects received placebo. Results. MVA-BN was generally well tolerated at both doses. No vaccine-related serious adverse events were identified. Transient local reactogenicity was more frequently seen at the higher dose. Neutralizing antibodies (NAb) to Vaccinia virus (VACV) were elicited by both doses of MVA-BN and were greater for the higher dose. Median peak anti-VACV NAb titers were 1:49 in the lower-dose group and 1:118 in the higher-dose group. T-cell immune responses to VACV were detected by an interferon γ enzyme-linked immunosorbent spot assay and were higher in the higher-dose group. Conclusions. MVA-BN is safe, well tolerated, and immunogenic in HSCT recipients. These data support the use of 10 8 TCID 50 of MVA-BN in this population. Clinical Trials Registration. NCT00565929.

We present here the phenomenon of gradual decay leading to plant mortality in vast stretches (measuring several square kilometres) of vibrant mangrove forests in the coastal wetlands of North and Middle Andaman. We interpret the phenomenon as an effect of static ground uplift following the 26 December 2004 Sumatra-Andaman earthquake. The decimetre to metre scale uplift has cut-off tidal water flow into those parts of the wetlands that were elevated from intertidal to supratidal levels. The consequent thermal shock, desiccation and gradual depletion of soil salinity affected the plants in the elevated parts. However, desiccation due to lack of tidal-water inflow caused the plant mortality which took the proportions of an ecological disaster about three to four years after the earthquake. The voluminous forest debris produced by the withered plants is likely to be preserved in the coastal sedimentary sequences as peat beds and serve as palaeoseismic indicators.

The thermodynamics of randomly quenched disordered Ising metamagnet has been studied by Monte Carlo simulations. The disorder has been implemented either by inserting nonmagnetic impurity or by uniformly distributed quenched random magnetic field. The staggered magnetisation (\\(M_s\\)) (calculated from the sublattice magnetisation) and the corresponding staggered susceptibility (\\(\\chi\\)) are studied as functions of the temperature (\\(T\\)). The antiferromagnetic phase transition has been found while cooling the system from the high temperature paramagnetic phase. The transition temperature(or pseudocritical temperature (\\(T_c\\))) has been found to decrease as the concentration (\\(p\\)) of nonmagnetic impurity increased. The nonmagnetic impurity dependent staggered magnetisation has been found to show the scaling behaviour \\(M_sp^b \\sim (T-T_c)p^a\\) (with \\(a \\cong -0.95\\), \\(b \\cong 0.09\\) and \\(T_c \\cong 4.45\\)) obtained through the data collapse. The zero temperature staggered magnetisation (\\(M_s(0)\\)) has been found to decrease linearly. The critical temperature(\\(T_c\\)) is showing a linear (\\(T_c=mp+c\\)) dependence with the concentration (\\(p\\)) of nonmagnetic impurity. The antiferromagnetic phase transition has been found to take place at lower temperature for the higher value of the width (\\(s\\)) of the uniformly distributed quenched random field. The critical temperature (\\(T_c\\)) has been found to show the nonlinear dependence (\\(T_c=a+bs+cs^2\\)) on the width (\\(s\\)) of the uniformly distributed random magnetic field. The extrapolation (both for \\(p \\to 0\\) and \\(s \\to 0\\)) restores the Neel temperature of three dimensional pure Ising antiferromagnet.

An extraordinarily strong and persistent earthquake swarm (Andaman swarm 2005) originated in the Andaman back-arc following the aftershock sequences of the 26 December 2004 Sumatra earthquake. The swarm (n = 651, mb max = 5.9) came mainly in two phases: January 26–31 and Feb.–Aug. 2005, in an area of size 90 × 40 km 2 , at the centre of which lies a broad bathymetric depression and high gravity zone. The swarm demonstrates a complex faulting series, initially the strike-slip motion followed by normal faulting in repetitive sequences, whose representative fault planes orient at high angle to the regional faults. The swarm character as well as the distribution of stress-axes and their correlation to tectonic features lends speculation for formation of a nascent rift segment in NW-SE direction at the doorstep of the Sewell Seamount. The swarm has given rise to 21 episodes of rifting activities of variable time extent within 26–31 January 2005. The r-t plots corresponding to the swarm data, modelled with variable hydraulic diffusivity (D) values 4, 6, 8 and 10 m 2 /s, suggest for excess pressure front from ascending magmatic fluid. This eventually heralded the rifting; causing pore pressure perturbations that propagated in accordance with known diffusion parabolic equations.

BackgroundHypertension is recognised as a major contributor to disease burden globally affecting 20% of adult population. More importantly it has become a significant problem in many developing countries experiencing epidemiological transition from communicable to non-communicable chronic diseases.ObjectiveThe study was to determine the prevalence of hypertension among Bangladeshi adult population by meta-analysis.MethodIn this meta-analysis the articles published during the period from 1995 to 2009 on the prevalence of hypertension among Bangladeshi adult population were identified by MEDLINE search included. We included those population based studies for this meta-analysis who clearly defined the diagnostic definition of hypertension and the age group (≥18 years). We could locate thirteen articles, among them seven articles were excluded from the current analysis because they did not fulfil our selection criteria. Then the prevalence of hypertension and their 95% CIs (p±1.96√pq/n) for the individual studies were calculated by using the data presented. Finally a pooled estimate was obtained from six studies.ResultThe pooled estimates for the prevalence of hypertension in 6430 adults are 13.5% (with 95% CI 12.66% to 14.34%).ConclusionThis meta-analysis clearly demonstrated that 13.5% adult population were at risk to develop cardiovascular and kidney diseases and this underscored the importance of screening of asymptomatic yet potentially harmful hypertensive disorders to combat the growing epidemic of Non-communicable Diseases.RecommendationLarge scale studies can be done including all the high risk population to represent the actual scenario of hypertension in Bangladeshi adult population.

In this paper, a DC line current measurement technique by sensing the magnetic field due to the steady current flowing through the line has been proposed. A circuit in which the n-channel enhancement-type MOSFET is used as magnetic field sensor is designed and tested for a wide range of DC line currents. The circuit is capable of measuring both the magnitude and direction of the DC current flowing through a line without any direct electrical contact. BS170 n-channel enhancement type MOSFET is used as magnetic field sensor. Experimental results are very encouraging to use this technique for measuring wide range of DC line currents without making any electrical contact.

In September 2017, a high-energy neutrino event detected by the IceCube Neutrino Observatory (IceCube-170922A) was associated, at the \\(3\\sigma\\) level, with a gamma-ray flare from the blazar TXS 0506+056. Cosmic rays that are accelerated in astrophysical sources can escape from their jets and interact with background radiation fields. Interactions with the extragalactic background light can produce pions and hence neutrinos, while interactions with the cosmic microwave background predominantly drive inverse Compton scattering, contributing to electromagnetic cascades in intergalactic space. The resulting secondary gamma-ray emission can be detected with high-energy gamma-ray telescopes. Here, we report on a new search for such cosmogenic cascade emission from the blazar TXS 0506+056, using a combined data set from the Fermi-Large Area Telescope and VERITAS. We compare the gamma-ray spectrum and neutrino observations with the predictions of cosmic-ray induced cascades in intergalactic space. The observed gamma-ray spectrum is modeled as a combination of the primary spectrum and the cascade spectrum. We apply a Monte Carlo simulation with a \\(\\Delta\\chi^2\\)-based likelihood analysis to jointly determine the best-fit parameters of a proton emission spectrum describing the data and derive constraints on the proton escape luminosity. Assuming a log-parabola primary photon spectrum, we find consistency with a proton injection spectral index of \\(\\alpha_{p} \\simeq 2.0\\) and a cutoff energy of \\(E_{p,\\text{max}} \\simeq 1.3 \\times 10^{16}\\) eV, and constrain the isotropic proton escape luminosity to \\(1 \\times 10^{44}\\) erg s\\(^{-1}\\) \\(\\lesssim L_{p, esc} \\lesssim 3 \\times 10^{45}\\) erg s\\(^{-1}\\) at the 90 % confidence level.