246 research outputs found

    Finite bounded expanding white hole universe without dark matter

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    The solution of Einstein's field equations in Cosmological General Relativity (CGR), where the Galaxy is at the center of a finite yet bounded spherically symmetrical isotropic gravitational field, is identical with the unbounded solution. This leads to the conclusion that the Universe may be viewed as a finite expanding white hole. The fact that CGR has been successful in describing the distance modulus verses redshift data of the high-redshift type Ia supernovae means that the data cannot distinguish between unbounded models and those with finite bounded radii of at least cτc \tau. Also it is shown that the Universe is spatially flat at the current epoch and has been at all past epochs where it was matter dominated.Comment: 11 pages, revised versio

    Spin density wave dislocation in chromium probed by coherent x-ray diffraction

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    We report on the study of a magnetic dislocation in pure chromium. Coherent x-ray diffraction profiles obtained on the incommensurate Spin Density Wave (SDW) reflection are consistent with the presence of a dislocation of the magnetic order, embedded at a few micrometers from the surface of the sample. Beyond the specific case of magnetic dislocations in chromium, this work may open up a new method for the study of magnetic defects embedded in the bulk.Comment: 8 pages, 7 figure

    Treatment of Marburg and Ebola hemorrhagic fevers: A strategy for testing new drugs and vaccines under outbreak conditions.

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    The filoviruses, Marburg and Ebola, have the dubious distinction of being associated with some of the highest case-fatality rates of any known infectious disease-approaching 90% in many outbreaks. In recent years, laboratory research on the filoviruses has produced treatments and vaccines that are effective in laboratory animals and that could potentially drastically reduce case-fatality rates and curtail outbreaks in humans. However, there are significant challenges in clinical testing of these products and eventual delivery to populations in need. Most cases of filovirus infection are recognized only in the setting of large outbreaks, often in the most remote and resource-poor areas of sub-Saharan Africa, with little infrastructure and few personnel experienced in clinical research. Significant political, legal, and socio-cultural barriers also exist. Here, we review the present research priorities and environment for field study of the filovirus hemorrhagic fevers and outline a strategy for future prospective clinical research on treatment and vaccine prevention

    The Fluorescence Detector of the Pierre Auger Observatory

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    The Pierre Auger Observatory is a hybrid detector for ultra-high energy cosmic rays. It combines a surface array to measure secondary particles at ground level together with a fluorescence detector to measure the development of air showers in the atmosphere above the array. The fluorescence detector comprises 24 large telescopes specialized for measuring the nitrogen fluorescence caused by charged particles of cosmic ray air showers. In this paper we describe the components of the fluorescence detector including its optical system, the design of the camera, the electronics, and the systems for relative and absolute calibration. We also discuss the operation and the monitoring of the detector. Finally, we evaluate the detector performance and precision of shower reconstructions.Comment: 53 pages. Submitted to Nuclear Instruments and Methods in Physics Research Section

    An Integrated TCGA Pan-Cancer Clinical Data Resource to Drive High-Quality Survival Outcome Analytics

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    For a decade, The Cancer Genome Atlas (TCGA) program collected clinicopathologic annotation data along with multi-platform molecular profiles of more than 11,000 human tumors across 33 different cancer types. TCGA clinical data contain key features representing the democratized nature of the data collection process. To ensure proper use of this large clinical dataset associated with genomic features, we developed a standardized dataset named the TCGA Pan-Cancer Clinical Data Resource (TCGA-CDR), which includes four major clinical outcome endpoints. In addition to detailing major challenges and statistical limitations encountered during the effort of integrating the acquired clinical data, we present a summary that includes endpoint usage recommendations for each cancer type. These TCGA-CDR findings appear to be consistent with cancer genomics studies independent of the TCGA effort and provide opportunities for investigating cancer biology using clinical correlates at an unprecedented scale. Analysis of clinicopathologic annotations for over 11,000 cancer patients in the TCGA program leads to the generation of TCGA Clinical Data Resource, which provides recommendations of clinical outcome endpoint usage for 33 cancer types

    Clonal hematopoiesis of indeterminate potential, DNA methylation, and risk for coronary artery disease

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    Age-related changes to the genome-wide DNA methylation (DNAm) pattern observed in blood are well-documented. Clonal hematopoiesis of indeterminate potential (CHIP), characterized by the age-related acquisition and expansion of leukemogenic mutations in hematopoietic stem cells (HSCs), is associated with blood cancer and coronary artery disease (CAD). Epigenetic regulators DNMT3A and TET2 are the two most frequently mutated CHIP genes. Here, we present results from an epigenome-wide association study for CHIP in 582 Cardiovascular Health Study (CHS) participants, with replication in 2655 Atherosclerosis Risk in Communities (ARIC) Study participants. We show that DNMT3A and TET2 CHIP have distinct and directionally opposing genome-wide DNAm association patterns consistent with their regulatory roles, albeit both promoting self-renewal of HSCs. Mendelian randomization analyses indicate that a subset of DNAm alterations associated with these two leading CHIP genes may promote the risk for CAD

    EmPHasis-10 health-related quality of life score predicts outcomes in patients with idiopathic and connective tissue disease-associated pulmonary arterial hypertension: results from a UK multi-centre study

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    Health-related quality of life (HRQoL) scores assess symptom burden in pulmonary arterial hypertension (PAH) but data regarding their role in prognostication and risk stratification are limited. We assessed these relationships using the emPHasis-10 HRQoL measure. 1745 patients with idiopathic or connective tissue disease-associated PAH who had completed emPHasis-10 questionnaires between 2014–17 at 6 UK referral centres were identified. Correlations with exercise capacity and WHO functional class (FC) were assessed, and exploratory risk stratification thresholds were tested. Moderate correlations were seen between emPHasis-10 scores and 6-minute walk distance (r=−0.546), incremental shuttle walking distance (r=−0.504) and WHO FC (r=0.497; p all <0.0001). Distribution of emPHasis-10 differed significantly between each WHO FC (p all <0.0001). At multivariate analysis, emPHasis-10, but not WHO FC, was an independent predictor of mortality. In a risk stratification approach, scores of 0–16, 17–33 and 34–50 identified incident patients with one-year mortality of 5%, 10% and 23%, respectively. Survival of patients in WHO FC III could be further stratified using an emPHasis-10 score ≥34 (p<0.01). At follow-up, patients with improved emPHasis-10 had improved exercise capacity (p<0.0001), and patients who transitioned risk groups demonstrated similar survival to patients originally in those risk groups. The emPHasis-10 score is an independent prognostic marker in patients with idiopathic or connective tissue disease-associated PAH. It has utility in risk stratification in addition to currently used parameters. Improvement in emPHasis-10 score is associated with improved exercise capacity
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