2,786 research outputs found

    Smeared BTZ Black Hole from Space Noncommutativity

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    We study a novel phenomena of smearing of black hole horizons from the effect of space noncommutativity. We present an explicit example in AdS3AdS_3 space, using the Chern-Simons formulation of gravity. This produces a smeared BTZ black hole which goes beyond the classical spacetime unexpectedly and there is {\it no} reality problem in our approach with the gauge group U(1,1)×U(1,1)U(1,1) \times U(1,1). The horizons are smeared, due to a splitting of the Killing horizon and the apparent horizon, and there is a metric signature change to Euclidean in the smeared region. The inner boundary of the smeared region acts as a trapped surface for timelike particles but the outer as a classical barrier for ingoing particles. The lightlike signals can escape from or reach the smeared region in a {\it finite} time, which indicates that {\it the black hole is not so dark, even classically.} In addition, it is remarked that the Hawking temperature can {\it not} be defined by the regularity in the Euclidean geometry except in the non-rotating case, and the origin can be smeared by a {\it new} (apparent) horizon.Comment: Added notes about boundary conditions, NC curvature, and torsion; Accepted in JHE

    Comments on "Entropy of 2D Black Holes from Counting Microstates"

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    In a recent letter, Cadoni and Mignemi proposed a formulation for the statistical computation of the 2D black holes entropy. We present a criticism about their formulation.Comment: 5 pages, Latex, no figure

    Correlation between thermal annealing temperature and Joule-heating based insulator-metal transition in VO2 nanobeams

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    Rapid thermal annealing of VO2 nanobeams in an ambient argon environment has been carried out at various temperatures after device fabrication. Our analysis revealed that increasing the annealing temperature from 200??C to 400??C results in the reduction of both ohmic and nanobeam resistances with an appreciable decrease in joule-heating based transition voltage and transition temperature, while samples annealed at 500??C exhibited a conducting rutile-phase like characteristics at room temperature. In addition, these variation trends were explored using a physical model and the results were found to be in agreement with the observed results, thus verifying the model.open2

    Massless Rotating Spacetimes in Four-Dimensional Horava Gravity

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    We study a particular exact solution for rotating spacetimes in four-dimensional Horava gravity, which has been proposed as a renormalizable gravity model without the ghost problem. We show that the massless Kerr spacetime or the massless Kerr-(A)dS spacetime in Einstein gravity is an exact solution in four-dimensional Horava for an arbitrary IR Lorentz-violation parameter lambda, but with an appropriate cosmological constant. In particular, for the massless topological Kerr-AdS black hole solution with the hyperbolic horizon topology or the massless Kerr-dS cosmological solution with the spherical horizon topology, there exist the ergosphere and the non-vanishing Hawking temperature, which imply the existence of negative mass black holes as well as positive mass spacetimes, by losing its mass from the massless ones via the Hawking radiation or Penrose process in the ergosphere.Comment: 10 pages, 3 figure

    Primary Tuberculous Abscess of the Spleen in an Immununocompetent Patient Diagnosed by Biochemical Markers and Radiologic Findings

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    Tuberculous splenic abscess in an immunocompetent patient is extremely rare. We came across a case of middle aged immunocompetent female who presented with abdominal distension, weight loss, and low grade fever. Abdominopelvic computed tomography showed multiple low density lesions in the spleen with ascites. Interferon-gamma release assay was positive and adenosine deaminase level of ascites was significantly high. No primary focus of infection was detected. The patient was diagnosed as having primary multiple tuberculous splenic abscesses with tuberculous peritonitis causing ascites. Follow up computed tomography, after completion of six month course of anti-tubercular therapy, showed splenic abscess and ascites completely disappeared

    Myocardial Infarction Thought to be Provoked by Local Epinephrine Injection During Endoscopic Submucosal Dissection

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    Due to its hemostatic effect, local epinephrine has been used to minimize mucosal bleeding during endoscopic submucosal dissection (ESD), but its clinical benefit remains unclear. On the other hand, several adverse events deemed to be caused by epinephrine have been observed during ESD. A 73-year-old woman developed myocardial infarction after ESD for a large rectal adenoma, and an 80-year-old woman developed abrupt chest tightness during ESD. In both patients, changes on electrocardiogram and elevated cardiac markers provided evidence of myocardial ischemia. The patients were transferred to the cardiac care unit and recovered completely. Up to our knowledge this is the first report of myocardial infarction thought to be provoked by submucosal epinephrine injection during ESD

    What sentiment attracts tourists? Analysis of tourist attractions based on consumer\u27s sentiment

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    This study tried to derive meaningful insights from consumers\u27 sentiments about tourist attractions. First, through descriptive statistics, seven sentiments representing tourist attractions were identified, and the unique sentiments about certain tourist attractions were identified. On the basis of the network analysis results, four interesting travel routes based on the sentiment theme were constructed, and four insights on the sentiment were presented. Finally, through the regression analysis, one negative word, two positive words, and three network centrality measures that significantly affect the number of visitors were identified. By applying social network analysis, more specific and differentiated conclusions have been drawn. It also provided useful implications for tourist attractions

    Development of Pseudomembranous Colitis Four Months after Initiation of Rifampicin

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    Pseudomembranous colitis (PMC) may develop with long-term antibiotic administration, but is rarely reported to be caused by antitubercular agents. We present a case of PMC that occurred 120 days after starting rifampicin. A 74-year-old man was diagnosed with pulmonary tuberculosis and started on a standard HERZ regimen (isoniazid, ethambutol, rifampicin, pyrazinamide). After 4 months of HERZ, he presented with frequent bloody, mucoid, jelly-like diarrhea and lower abdominal pain. Sigmoidoscopy revealed multiple whitish plaques with edematous mucosa that were compatible with PMC. Biopsies from these lesions showed ulcer-related necrotic and granulation tissue. We stopped antitubercular treatment and started the patient on oral metronidazole. His symptoms completely resolved within 2 weeks. Antitubercular treatment was restarted by replacing rifampicin with levofloxacin. The patient did not present with diarrhea or bloody stool throughout the rest of treatment
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