Development of a Thomson X-ray Polarimeter

We describe the current status of the design and development of a Thomson X-ray polarimeter suitable for a small satellite mission. Currently we are considering two detector geometries, one using rectangular detectors placed on four sides of a scattering element and the other using a single cylindrical detector with the scattering element at the center. The rectangular detector configuration has been fabricated and tested. The cylindrical detector is currently under fabrication. In order to compensate any pointing offset of the satellite, a collimator with a flat topped response has been developed that provides a constant effective area over an angular range. We have also developed a double crystal monochromator/polariser for the purpose of test and calibration of the polarimeter. Preliminary test results from the developmental activities are presented here.Comment: 4 pages, 5 figures, in "X-ray Polarimetry: A New Window in Astrophysics", edited by R. Bellazzini, E. Costa, G. Matt and G. Tagliaferri, Cambridge University Press (proceedings of "The Coming of Age of X-ray Polarimetry," Rome, Italy, April 27-30, 2009

The persistence of equatorial spread F - an analysis on seasonal, solar activity and geomagnetic activity aspects

The persistence (duration) of Equatorial Spread F (ESF), which has significant impact on communication systems, is addressed. Its behavior during different seasons and geomagnetic activity levels under the solar maximum (2001) and minimum (2006) conditions, is reported using the data from the magnetic equatorial location of Trivandrum (8.5° N; 77° E; dip 0.5° N) in India. The study reveals that the persistence of the irregularities can be estimated to a reasonable extent by knowing the post sunset F region vertical drift velocity (Vz) and the magnetic activity index Kp. Any sort of advance information on the possible persistence of the ionospheric irregularities responsible for ESF is important for understanding the scintillation morphology, and the results which form the first step in this direction are presented and discussed

Magnetic Calorimeter Option for the Lynx X-Ray Microcalorimeter

One option for the detector technology to implement the Lynx x-ray microcalorimeter (LXM) focal plane arrays is the metallic magnetic calorimeter (MMC). Two-dimensional imaging arrays of MMCs measure the energy of x-ray photons by using a paramagnetic sensor to detect the temperature rise in a microfabricated x-ray absorber. While small arrays of MMCs have previously been demonstrated that have energy resolution better than the 3 eV requirement for LXM, we describe LXM prototype MMC arrays that have 55,800 x-ray pixels, thermally linked to 5688 sensors in hydra configurations, and that have sensor inductance increased to avoid signal loss from the stray inductance in the large-scale arrays when the detectors are read out with microwave superconducting quantum interference device multiplexers, and that use multilevel planarized superconducting wiring to provide low-inductance, low-crosstalk connections to each pixel. We describe the features of recently tested MMC prototype devices and simulations of expected performance in designs opti- mized for the three subarray types in LXM

Serum Cortisol Level as a Predictor of In-Hospital Mortality in Patients Undergoing Primary Percutaneous Intervention for ST Segment Elevation Myocardial Infarction

Introduction: Various laboratory markers have been proposed to assess prognosis in myocardial infarction. Serum cortisol is one such laboratory marker. There are only few studies done in the recent past which prove that cortisol is a prognostic marker in STEMI.Methods: We studied a total of 168 patients who presented with STEMI and underwent primary percutaneous intervention (PPCI) within 12 hours of symptom onset between April 2016 and November 2016.Results: The average age of study population was 61 ± 0.12 years. Males were predominant (n = 132, 78.57%). 155 patients survived, whereas 13 patients died in the hospital. Mean syntax score was 16.65 ±5. 33 among patients who died, whereas it was 13.11 ± 5.62 among survivors (P = 0.03). Mean cortisol was significantly higher among the patients who died (46.13 ± 14.61 mcg/dl) than the survivors (31.16 ± 13.16 mcg/dl) (P = 0.003). The ROC AUC for in-hospital mortality was 0.77 (95% confidence interval [CI], 0.645–0.897). An optimal cut-point identified from the ROC curve was a random serum cortisol concentration of 33.66 mcg/dl, with corresponding sensitivity and specificity of 69.2 % and 64 %, respectively. At a cut-point of 29.55 mcg/dl, sensitivity and specificity were 84.6 and 50 %, respectively.Conclusion: This study showed that serum cortisol level is a strong predictor of mortality in patients undergoing PPCI for STEMI. Levels more than 33.66 mcg/dl can predict mortality with a sensitivity of almost 70 percent and specificity of 64 percent

Transitional intermittency in boundary layers subjected to pressure gradient

Results are reported from an extensive series of experiments on boundary layers in which the location of pressure gradient and transition onset could be varied almost independently, by judicious use of tunnel wall liners and transition-fixing devices. The experiments show that the transition zone is sensitive to the pressure gradient especially near onset, and can be significantly asymmetric; no universal similarity appears valid in general. Observed intermittency distributions cannot be explained on the basis of the hypothesis, often made, that the spot propagates at speeds proportional to the local free-stream velocity but is otherwise unaffected by the pressure gradient

Observations on Stratospheric-Mesospheric-Thermospheric temperatures using Indian MST radar and co-located LIDAR during Leonid Meteor Shower (LMS)

International audienceThe temporal and height statistics of the occurrence of meteor trails during the Leonid meteor shower revealed the capability of the Indian MST radar to record large numbers of meteor trails. The distribution of radio meteor trails due to a Leonid meteor shower in space and time provided a unique opportunity to construct the height profiles of lower thermospheric temperatures and winds, with good time and height resolution. There was a four-fold increase in the meteor trails observed during the LMS compared to a typical non-shower day. The temperatures were found to be in excellent continuity with the temperature profiles below the radio meteor region derived from the co-located Nd-Yag LIDAR and the maximum height of the temperature profile was extended from the LIDAR to ~110 km. There are, how-ever, some significant differences between the observed profiles and the CIRA-86 model profiles. The first results on the meteor statistics and neutral temperature are presented and discussed below. Key words. Atmospheric composition and structure (pres-sure, density, and temperature) History of geophysics (at-mospheric sciences) Meteorology and atmospheric dynamics (middle atmosphere dynamics

Multimode bolometer development for the PIXIE instrument

The Primordial Inflation Explorer (PIXIE) is an Explorer-class mission concept designed to measure the polarization and absolute intensity of the cosmic microwave background. In the following, we report on the design, fabrication, and performance of the multimode polarization-sensitive bolometers for PIXIE, which are based on silicon thermistors. In particular we focus on several recent advances in the detector design, including the implementation of a scheme to greatly raise the frequencies of the internal vibrational modes of the large-area, low-mass optical absorber structure consisting of a grid of micromachined, ion-implanted silicon wires. With $\sim30$ times the absorbing area of the spider-web bolometers used by Planck, the tensioning scheme enables the PIXIE bolometers to be robust in the vibrational and acoustic environment at launch of the space mission. More generally, it could be used to reduce microphonic sensitivity in other types of low temperature detectors. We also report on the performance of the PIXIE bolometers in a dark cryogenic environment.Comment: 10 pages, 7 figure

Seasonal dependence of the "forecast parameter" based on the EIA characteristics for the prediction of Equatorial Spread F (ESF)

In an earlier study, Thampi et al. (2006) have shown that the strength and asymmetry of Equatorial Ionization Anomaly (EIA), obtained well ahead of the onset time of Equatorial Spread F (ESF) have a definite role on the subsequent ESF activity, and a new "forecast parameter" has been identified for the prediction of ESF. This paper presents the observations of EIA strength and asymmetry from the Indian longitudes during the period from August 2005-March 2007. These observations are made using the line of sight Total Electron Content (TEC) measured by a ground-based beacon receiver located at Trivandrum (8.5° N, 77° E, 0.5° N dip lat) in India. It is seen that the seasonal variability of EIA strength and asymmetry are manifested in the latitudinal gradients obtained using the relative TEC measurements. As a consequence, the "forecast parameter" also displays a definite seasonal pattern. The seasonal variability of the EIA strength and asymmetry, and the "forecast parameter" are discussed in the present paper and a critical value for has been identified for each month/season. The likely "skill factor" of the new parameter is assessed using the data for a total of 122 days, and it is seen that when the estimated value of the "forecast parameter" exceeds the critical value, the ESF is seen to occur on more than 95% of cases

Development of SSR markers for Robusta coffee (Coffea canephora)

Coffee has long been bred with the view of improving important agronomic characteristics such as yield, bean size, cup quality, caffeine content, disease, drought resistance etc. However, the progress in coffee breeding using conventional approaches has been slow due to the narrow genetic base of cultivated coffee and the long generation time. The use of modern tools of molecular biology holds great promise for the faster development of improved varieties. A primary prerequisite is the availability of suitable marker systems. Co-dominant maker systems like SSRs provides comprehensive genome coverage, are locus specific and multi allelic. However, the number of SSR markers available for coffee is limited and there is an urgent need for generating large number of microsatellite markers. Aim of the study was to develop and characterize a comprehensive set of genomic and genic SSR markers for Robusta coffee by pre-cloning enrichment strategy and also by annotating Robusta specific unigene sequences. The pre-cloning enrichment (selective hybridization) strategy followed in the study resulted in identification of 405 SSRs in 267 sequences. The 405 SSRs isolated consisted of more of mono-nucleotide repeats (40.2%) followed by penta (33.3%), di (12.1%), tri (10.6%) and tetra (3.7%) nucleotide repeats. Among the genic SSRs identified, 43.7 per cent contained penta-repeat motifs followed by 22.5 per cent and 22.5 per cent sequences with hexa and mono repeat motifs respectively. The remaining identified motifs consisted of 5.5 per cent tri nucleotide repeat motifs, 3.5 per cent di repeat motifs and 2.2 per cent tetra repeat motifs. The study resulted in development of 31 genomic SSRs and 86 genic SSRs which were validated for locus specific amplification