The High Energy Telescope on EXIST

The Energetic X-ray Imaging Survey Telescope (EXIST) is a proposed next generation multi-wavelength survey mission. The primary instrument is a High Energy telescope (HET) that conducts the deepest survey for Gamma-ray Bursts (GRBs), obscured-accreting and dormant Supermassive Black Holes and Transients of all varieties for immediate followup studies by the two secondary instruments: a Soft X-ray Imager (SXI) and an Optical/Infrared Telescope (IRT). EXIST will explore the early Universe using high redshift GRBs as cosmic probes and survey black holes on all scales. The HET is a coded aperture telescope employing a large array of imaging CZT detectors (4.5 m^2, 0.6 mm pixel) and a hybrid Tungsten mask. We review the current HET concept which follows an intensive design revision by the HET imaging working group and the recent engineering studies in the Instrument and Mission Design Lab at the Goddard Space Flight Center. The HET will locate GRBs and transients quickly (<10-30 sec) and accurately (< 20") for rapid (< 1-3 min) onboard followup soft X-ray and optical/IR (0.3-2.2 micron) imaging and spectroscopy. The broad energy band (5-600 keV) and the wide field of view (~90 deg x 70 deg at 10% coding fraction) are optimal for capturing GRBs, obscured AGNs and rare transients. The continuous scan of the entire sky every 3 hours will establish a finely-sampled long-term history of many X-ray sources, opening up new possibilities for variability studies.Comment: 10 pages, 6 figures, 3 tables, SPIE conference proceedings (UV, X-ray, and Gamma-Ray Space Instrumentation for Astronomy XVI, 7435-9

The Proposed High Energy Telescope (HET) for EXIST

The hard X-ray sky now being studied by INTEGRAL and Swift and soon by NuSTAR is rich with energetic phenomena and highly variable non-thermal phenomena on a broad range of timescales. The High Energy Telescope (HET) on the proposed Energetic X-ray Imaging Survey Telescope (EXIST) mission will repeatedly survey the full sky for rare and luminous hard X-ray phenomena at unprecedented sensitivities. It will detect and localize (<20", at 5 sigma threshold) X-ray sources quickly for immediate followup identification by two other onboard telescopes - the Soft X-ray imager (SXI) and Optical/Infrared Telescope (IRT). The large array (4.5 m^2) of imaging (0.6 mm pixel) CZT detectors in the HET, a coded-aperture telescope, will provide unprecedented high sensitivity (~0.06 mCrab Full Sky in a 2 year continuous scanning survey) in the 5 - 600 keV band. The large field of view (90 deg x 70 deg) and zenith scanning with alternating-orbital nodding motion planned for the first 2 years of the mission will enable nearly continuous monitoring of the full sky. A 3y followup pointed mission phase provides deep UV-Optical-IR-Soft X-ray and Hard X-ray imaging and spectroscopy for thousands of sources discovered in the Survey. We review the HET design concept and report the recent progress of the CZT detector development, which is underway through a series of balloon-borne wide-field hard X-ray telescope experiments, ProtoEXIST. We carried out a successful flight of the first generation of fine pixel large area CZT detectors (ProtoEXIST1) on Oct 9, 2009. We also summarize our future plan (ProtoEXIST2 & 3) for the technology development needed for the HET.Comment: 10 pages, 13 figures, 2 tables, SPIE Conference "Astronomical Telescopes and Instrumentation 2010"; to appear in Proceedings SPIE (2010

Association of plasma fibrinogen and development of complications in type 2 diabetes mellitus

Background: Fibrinogen is a glycoprotein produced by the liver that plays a crucial role in blood clotting. Elevated levels of fibrinogen have been associated with an increased risk of cardio vascular disease, stroke and other chronic conditions. Several studies have investigated the relationship between fibrinogen and diabetes mellitus. Furthermore, fibrinogen has been suggested to play a role in pathogenesis of diabetes and its complications by promoting inflammation and endothelial dysfunction. The aim of the study was done to study association of fibrinogen levels and development of complications of diabetes mellitus. Methods: A cross sectional observational study was conducted at medicine department of Dhiraj Hospital, Vadodara. Total of 114 diabetes mellitus patients were studied. The level of fibrinogen as well as presence of various risk factors like smoking, hypertension, obesity, dyslipidemia and different microvascular and macro-vascular complications were assessed. There were no conflict of interest. Results: Of 114 patients smoking, overweight, hypertension, uncontrolled diabetes and dyslipidemia was reported in 54.4%, 30.7%, 41.2%, 28.1% and 60.5% respectively. Microvascular complication like retinopathy, nephropathy and neuropathy was reported in 34.2%, 40.4% and 21.1% patients respectively. Macrovascular complications like coronary artery disease and stroke was reported in 20.2% and 16.7% patients respectively. Average level of fibrinogen was found higher amongst diabetic patients with microvascular as well as macrovascular complications. Conclusions: Serum fibrinogen level was found to be higher among patients with poor glycemic control, dyslipidemia, hypertension and higher BMI. A positive correlation was found between the level of fibrinogen and various complications of diabetes mellitus.

Daily life stress and the cortisol awakening response : testing the anticipation hypothesis

Acknowledgments We thank Paul Stewart for his contribution to data collection and Dr Matthew Jones for programming the handheld computers. Author Contributions Conceived and designed the experiments: WS DJP. Performed the experiments: DJP. Analyzed the data: WS. Wrote the paper: WS DJP.Peer reviewedPublisher PD

Quantized Majorana conductance

Majorana zero-modes hold great promise for topological quantum computing. Tunnelling spectroscopy in electrical transport is the primary tool to identify the presence of Majorana zero-modes, for instance as a zero-bias peak (ZBP) in differential-conductance. The Majorana ZBP-height is predicted to be quantized at the universal conductance value of 2e2/h at zero temperature. Interestingly, this quantization is a direct consequence of the famous Majorana symmetry, 'particle equals antiparticle'. The Majorana symmetry protects the quantization against disorder, interactions, and variations in the tunnel coupling. Previous experiments, however, have shown ZBPs much smaller than 2e2/h, with a recent observation of a peak-height close to 2e2/h. Here, we report a quantized conductance plateau at 2e2/h in the zero-bias conductance measured in InSb semiconductor nanowires covered with an Al superconducting shell. Our ZBP-height remains constant despite changing parameters such as the magnetic field and tunnel coupling, i.e. a quantized conductance plateau. We distinguish this quantized Majorana peak from possible non-Majorana origins, by investigating its robustness on electric and magnetic fields as well as its temperature dependence. The observation of a quantized conductance plateau strongly supports the existence of non-Abelian Majorana zero-modes in the system, consequently paving the way for future braiding experiments.Comment: 5 figure

Electric field tunable superconductor-semiconductor coupling in Majorana nanowires

We study the effect of external electric fields on superconductor-semiconductor coupling by measuring the electron transport in InSb semiconductor nanowires coupled to an epitaxially grown Al superconductor. We find that the gate voltage induced electric fields can greatly modify the coupling strength, which has consequences for the proximity induced superconducting gap, effective g-factor, and spin-orbit coupling, which all play a key role in understanding Majorana physics. We further show that level repulsion due to spin-orbit coupling in a finite size system can lead to seemingly stable zero bias conductance peaks, which mimic the behavior of Majorana zero modes. Our results improve the understanding of realistic Majorana nanowire systems.Comment: 10 pages, 5 figures, supplemental information as ancillary fil

Candida albicans repetitive elements display epigenetic diversity and plasticity

Transcriptionally silent heterochromatin is associated with repetitive DNA. It is poorly understood whether and how heterochromatin differs between different organisms and whether its structure can be remodelled in response to environmental signals. Here, we address this question by analysing the chromatin state associated with DNA repeats in the human fungal pathogen Candida albicans. Our analyses indicate that, contrary to model systems, each type of repetitive element is assembled into a distinct chromatin state. Classical Sir2-dependent hypoacetylated and hypomethylated chromatin is associated with the rDNA locus while telomeric regions are assembled into a weak heterochromatin that is only mildly hypoacetylated and hypomethylated. Major Repeat Sequences, a class of tandem repeats, are assembled into an intermediate chromatin state bearing features of both euchromatin and heterochromatin. Marker gene silencing assays and genome-wide RNA sequencing reveals that C. albicans heterochromatin represses expression of repeat-associated coding and non-coding RNAs. We find that telomeric heterochromatin is dynamic and remodelled upon an environmental change. Weak heterochromatin is associated with telomeres at 30?°C, while robust heterochromatin is assembled over these regions at 39?°C, a temperature mimicking moderate fever in the host. Thus in C. albicans, differential chromatin states controls gene expression and epigenetic plasticity is linked to adaptation

Measuring empathy in schizophrenia:The Empathic Accuracy Task and its correlation with other empathy measures

Introduction: Empathy is an interpersonal process impaired in schizophrenia. Past studies have mainly used questionnaires or performance-based tasks with static cues to measure cognitive and affective empathy. We used the Empathic Accuracy Task (EAT) designed to capture dynamic aspects of empathy by using videoclips in which perceivers continuously judge emotionally charged stories. We compared individuals with schizophrenia with a healthy comparison group and assessed correlations among EAT and three other commonly used empathy measures. Method: Patients (n = 92) and a healthy comparison group (n = 42) matched for age, gender and education completed the EAT, the Interpersonal Reactivity Index, Questionnaire of Cognitive and Affective Empathy and Faux Pas. Differences between groups were analyzed and correlations were calculated between empathy measurement instruments. Results: The groups differed in EAT performance, with the comparison group outperforming patients. A moderating effect was found for emotional expressivity of the target: while both patients and the comparison group scored low when judging targets with low expressivity, the comparison group performed better than patients with more expressive targets. Though there were also group differences on the empathy questionnaires, EAT performance did not correlate with questionnaire scores. Conclusions: Individuals with schizophrenia benefit less from the emotional expressivity of other people than the comparison group, which contributes to their impaired empathic accuracy. The lack of correlation between the EAT and the questionnaires suggests a distinction between self-report empathy and actual empathy performance. To explore empathic difficulties in real life, it is important to use instruments that take the interpersonal perspective into account. (C) 2019 Published by Elsevier B.V