898 research outputs found

    Bacteriological profile and antibiogram of blood culture isolates from patients of rural tertiary care hospital

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    Microbial invasion of blood stream is associated with significant mortality and morbidity. Identification of bacterial isolates and antibiotic susceptibility of bacteria isolated from blood culture would guide the antibiotics treatment for patients with bacteremia. 1) To determine age – wise blood culture positivity rate in bacteremia 2) To identify age – wise common bacterial species isolates in bacteremia 3) To determine Antibiotic sensitivity pattern of the bacterial isolates. Atotal of 247 blood culture samples received from various clinical departments of rural teaching hospital from August 2013 to September 2015 were included in the study. Samples were collected in brain heart infusion broth. Identification of isolates and antimicrobial susceptibility was done as per standard microbiological methods. Out of 247 specimens bacteria sp. was isolated from 46 (18.62%) samples. Blood culture positivity was noted highest among neonates age group (38.71%). Lowest rate was observed among elders (4.55%). Klebsiella pneumoniae, Coagulase negative staphylococcus (CONs), and S. aureus were common blood culture isolates. In neonates Klebsiella pneumoniae was the most common isolate. Out of 27 gram negative bacilli, 14 (51.85%) were extended spectrum betalactamases (ESBL) positive. High resistance was noted against amoxycillin and amoxicillin/clavulanic acid and third generation cephalosporins in all gram negative organisms except, S. typhi. Out of 12 Staphylococcus sp., none of these were methicillin resistant. Routine antibiotic susceptibility surveillance helps in choice of antibiotics for treatment, identification of resistance and control of its spread. Published by the International journal of Microbiology and Mycology (IJMM

    Continuous Uniform Finite Time Stabilization of Planar Controllable Systems

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    Continuous homogeneous controllers are utilized in a full state feedback setting for the uniform finite time stabilization of a perturbed double integrator in the presence of uniformly decaying piecewise continuous disturbances. Semiglobal strong C1\mathcal{C}^1 Lyapunov functions are identified to establish uniform asymptotic stability of the closed-loop planar system. Uniform finite time stability is then proved by extending the homogeneity principle of discontinuous systems to the continuous case with uniformly decaying piecewise continuous nonhomogeneous disturbances. A finite upper bound on the settling time is also computed. The results extend the existing literature on homogeneity and finite time stability by both presenting uniform finite time stabilization and dealing with a broader class of nonhomogeneous disturbances for planar controllable systems while also proposing a new class of homogeneous continuous controllers

    Improving adaptive bagging methods for evolving data streams

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    We propose two new improvements for bagging methods on evolving data streams. Recently, two new variants of Bagging were proposed: ADWIN Bagging and Adaptive-Size Hoeffding Tree (ASHT) Bagging. ASHT Bagging uses trees of different sizes, and ADWIN Bagging uses ADWIN as a change detector to decide when to discard underperforming ensemble members. We improve ADWIN Bagging using Hoeffding Adaptive Trees, trees that can adaptively learn from data streams that change over time. To speed up the time for adapting to change of Adaptive-Size Hoeffding Tree (ASHT) Bagging, we add an error change detector for each classifier. We test our improvements by performing an evaluation study on synthetic and real-world datasets comprising up to ten million examples

    Evaluation of semiempirical atmospheric density models for orbit determination applications

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    This paper presents the results of an investigation of the orbit determination performance of the Jacchia-Roberts (JR), mass spectrometer incoherent scatter 1986 (MSIS-86), and drag temperature model (DTM) atmospheric density models. Evaluation of the models was performed to assess the modeling of the total atmospheric density. This study was made generic by using six spacecraft and selecting time periods of study representative of all portions of the 11-year cycle. Performance of the models was measured for multiple spacecraft, representing a selection of orbit geometries from near-equatorial to polar inclinations and altitudes from 400 kilometers to 900 kilometers. The orbit geometries represent typical low earth-orbiting spacecraft supported by the Goddard Space Flight Center (GSFC) Flight Dynamics Division (FDD). The best available modeling and orbit determination techniques using the Goddard Trajectory Determination System (GTDS) were employed to minimize the effects of modeling errors. The latest geopotential model available during the analysis, the Goddard earth model-T3 (GEM-T3), was employed to minimize geopotential model error effects on the drag estimation. Improved-accuracy techniques identified for TOPEX/Poseidon orbit determination analysis were used to improve the Tracking and Data Relay Satellite System (TDRSS)-based orbit determination used for most of the spacecraft chosen for this analysis. This paper shows that during periods of relatively quiet solar flux and geomagnetic activity near the solar minimum, the choice of atmospheric density model used for orbit determination is relatively inconsequential. During typical solar flux conditions near the solar maximum, the differences between the JR, DTM, and MSIS-86 models begin to become apparent. Time periods of extreme solar activity, those in which the daily and 81-day mean solar flux are high and change rapidly, result in significant differences between the models. During periods of high geomagnetic activity, the standard JR model was outperformed by DTM. Modification of the JR model to use a geomagnetic heating delay of 3 hours, as used in DTM, instead of the 6.7-hour delay produced results comparable to or better than the DTM performance, reducing definitive orbit solution ephermeris overlap differences by 30 to 50 percent. The reduction in the overlap differences would be useful for mitigating the impact of geomagnetic storms on orbit prediction

    Accurate orbit determination strategies for the tracking and data relay satellites

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    The National Aeronautics and Space Administration (NASA) has developed the Tracking and Data Relay Satellite (TDRS) System (TDRSS) for tracking and communications support of low Earth-orbiting satellites. TDRSS has the operational capability of providing 85% coverage for TDRSS-user spacecraft. TDRSS currently consists of five geosynchronous spacecraft and the White Sands Complex (WSC) at White Sands, New Mexico. The Bilateration Ranging Transponder System (BRTS) provides range and Doppler measurements for each TDRS. The ground-based BRTS transponders are tracked as if they were TDRSS-user spacecraft. Since the positions of the BRTS transponders are known, their radiometric tracking measurements can be used to provide a well-determined ephemeris for the TDRS spacecraft. For high-accuracy orbit determination of a TDRSS user, such as the Ocean Topography Experiment (TOPEX)/Poseidon spacecraft, high-accuracy TDRS orbits are required. This paper reports on successive refinements in improved techniques and procedures leading to more accurate TDRS orbit determination strategies using the Goddard Trajectory Determination System (GTDS). These strategies range from the standard operational solution using only the BRTS tracking measurements to a sophisticated iterative process involving several successive simultaneous solutions for multiple TDRSs and a TDRSS-user spacecraft. Results are presented for GTDS-generated TDRS ephemerides produced in simultaneous solutions with the TOPEX/Poseidon spacecraft. Strategies with different user spacecraft, as well as schemes for recovering accurate TDRS orbits following a TDRS maneuver, are also presented. In addition, a comprehensive assessment and evaluation of alternative strategies for TDRS orbit determination, excluding BRTS tracking measurements, are presented

    Effect of Bacilli Calmette-Guerin vaccine on severe combined immunodeficiency patient: a narrative review and proposed workup algorithm

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    This systematic review critically investigates the administration of the Bacillus Calmette-Guérin (BCG) vaccine in neonates with severe combined immunodeficiency (SCID). The BCG vaccine, derived from Mycobacterium bovis, is a live attenuated vaccine recognized for its significant role in mitigating the impacts of tuberculosis (TB) in endemic areas. Despite its beneficial effects in controlling TB, safety and efficacy concerns have been raised when the vaccine is administered to SCID patients, who have a severe dysfunction or absence of the immune system. The potential for the vaccine to lead to severe complications due to the immunocompromised state of SCID patients necessitates a comprehensive investigation. To better understand these issues, a thorough literature review was carried out, integrating data from clinical trials and observational studies available on the PubMed database. An extensive review and analysis of 32 relevant articles revealed substantial evidence of complications from BCG vaccination in SCID patients. These findings emphasize the urgency for a more effective pre-vaccination screening process to circumvent potential adverse effects. Given the crucial role of the BCG vaccine in controlling TB, its potential to induce severe complications in SCID patients warrants careful consideration. Therefore, this review proposes an in-depth screening algorithm for newborns before BCG vaccination administration. The goal is to prevent these adverse events, offering critical insights to health policymakers, researchers, and clinicians in the field

    On the Absorption of X-rays in the Interstellar Medium

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    We present an improved model for the absorption of X-rays in the ISM intended for use with data from future X-ray missions with larger effective areas and increased energy resolution such as Chandra and XMM, in the energy range above 100eV. Compared to previous work, our formalism includes recent updates to the photoionization cross section and revised abundances of the interstellar medium, as well as a treatment of interstellar grains and the H2molecule. We review the theoretical and observational motivations behind these updates and provide a subroutine for the X-ray spectral analysis program XSPEC that incorporates our model.Comment: ApJ, in press, for associated software see http://astro.uni-tuebingen.de/nh

    The LEECH Exoplanet Imaging Survey: Limits on Planet Occurrence Rates Under Conservative Assumptions

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    We present the results of the largest LL^{\prime} (3.8 μ3.8~\mum) direct imaging survey for exoplanets to date, the Large Binocular Telescope Interferometer (LBTI) Exozodi Exoplanet Common Hunt (LEECH). We observed 98 stars with spectral types from B to M. Cool planets emit a larger share of their flux in LL^{\prime} compared to shorter wavelengths, affording LEECH an advantage in detecting low-mass, old, and cold-start giant planets. We emphasize proximity over youth in our target selection, probing physical separations smaller than other direct imaging surveys. For FGK stars, LEECH outperforms many previous studies, placing tighter constraints on the hot-start planet occurrence frequency interior to 20\sim20 au. For less luminous, cold-start planets, LEECH provides the best constraints on giant-planet frequency interior to 20\sim20 au around FGK stars. Direct imaging survey results depend sensitively on both the choice of evolutionary model (e.g., hot- or cold-start) and assumptions (explicit or implicit) about the shape of the underlying planet distribution, in particular its radial extent. Artificially low limits on the planet occurrence frequency can be derived when the shape of the planet distribution is assumed to extend to very large separations, well beyond typical protoplanetary dust-disk radii (50\lesssim50 au), and when hot-start models are used exclusively. We place a conservative upper limit on the planet occurrence frequency using cold-start models and planetary population distributions that do not extend beyond typical protoplanetary dust-disk radii. We find that 90%\lesssim90\% of FGK systems can host a 7 to 10 MJupM_{\mathrm{Jup}} planet from 5 to 50 au. This limit leaves open the possibility that planets in this range are common.Comment: 31 pages, 13 figures, accepted to A
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