558 research outputs found

    Microprocessor-controlled pulsed NQR spectrometer for automatic acquisition of Zeeman pertubed nuclear quadrupole spin echo envelope modulations (ZSEEM)

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    A simple microprocessor-controlled pulsed NQR spectrometer system has been developed with the capability to acquire Zeeman perturbed spin echo envelope modulations (ZSEEM). The CPU of the system is based on the Intel Corporation 8085A microprocessor. The performance of the spectrometer is illustrated with the presentation of ZSEEM spectra of NaCIO₃ and KC1O₃

    Tidal Turbine Benchmarking Exercise: Environmental Characterisation and Geometry Specification

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    Uncertainty in tidal turbine loading contributes significantly to conservatism in turbine design. This uncertainty originates not only from a lack of knowledge of the flow field at a particular site, but also from lack of understanding of the fundamental physics which govern the loading and performance of tidal turbines in unsteady and turbulent flow regimes. In order to reduce this conservatism and the costs associated, the mathematical and engineering models used in turbine design must be improved. To facilitate the development of these models requires scale experimental data for validation. However, few well-documented experimental data sets are available for tidal turbines, especially at scales large enough to achieve Reynolds number independence and comparability to full scale devices.This paper reports on the initial phases of a tidal turbine benchmarking project that will conduct a large laboratory scale experimental campaign on a highly instrumented 1.6m diameter tidal rotor. The turbine will be tested in well defined flow conditions, including unsteadiness created by free surface waves, as well as freestream turbulence, with instrumentation to determine edgewise and flapwise loading distributions along the blades as they rotate through the unsteady flows. As towing tanks by their nature have low levels of freestream turbulence, a carriage-mounted turbulence grid will be utilised to generate sufficient freestream turbulence in a well-defined manner.In this paper the turbine geometry and test conditions are specified, as well as providing details of the rotor’s hydrodynamic design process. Additionally, the results of a flow characterisation of the carriage-mounted turbulence grid via Acoustic Doppler Velocimetry are presented. The turbulence grid produced a mean turbulence intensity of 3:5% across the region in which the turbine will be tested, and a very uniform flow profile of 0:913 times the upstream velocity

    Prevalence & antibiogram of Pseudomonas aeruginosa at S.S.G. Hospital, Baroda, Gujarat, India

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    Background: Pseudomonas aeruginosa is a gram negative bacterium that continues to be a major cause of opportunistic nosocomial infections, causing around 9-10% of hospital infections. It is hard to treat because of intrinsic resistance of the species and its ability to further resistance to multiple groups including β-lactams, aminoglycosides and fluoroquinolones. Aims: This study was undertaken to determine the prevalence of Pseudomonas and their susceptibility pattern at S.S.G. Hospital, BARODA. Materials and Methods: Between March 2015 to May 2015, 150strains of P. aeruginosa were isolated from different clinical specimens. The samples were selected on the basis of their growth on Mac Conkey and nutrient agar medium with oxidase positive. Colonies were subjected to biochemical tests to identify species. Antimicrobial susceptibility of all the isolates was performed by disc diffusion (Kirby –Bauer) method according to CLSIs guidelines. Results: Majority of isolates of P. aeruginosa were obtained from specimens of blood, pus, wound, sputum, tracheal aspirates, pleural fluid, ICD fluid, bile fluid.The prevalence of pathogen was 4.15% and 98% pathogens were sensitive Piperacillin+Tazobactum followed by Meropenem (93.33%), Levofloxacin (92.66%) , Ceftazidime (82%), Cefoperazone(81.33%), Piperacillin (80.66%), Amikacin(56%), Gentamicin(54.66%). Conclusion: The results confirmed the occurrence of drug resistant strains of P. aeruginosa. Meropenem, Levofloxacin and Piperacillin+Tazobactumwere found to be the most effective antimicrobial drugs. It is rational treatment regimens prescription by the physicians to limit the further spread of antimicrobial resistance among the P. aeruginosa strains

    The luminosities, sizes and velocity dispersions of Brightest Cluster Galaxies: Implications for formation history

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    The size-luminosity relation of early-type Brightest Cluster Galaxies (BCGs), R_e ~ L^0.88, is steeper than that for the bulk of the early-type galaxy population, for which R_e ~ L^0.68. In addition, although BCGs are hardly offset from the Fundamental Plane defined by the bulk of the early-type population, they show considerably smaller scatter. The larger than expected sizes of BCGs, and the increased homogeneity, are qualitatively consistent with models which seek to explain the colors of the most massive galaxies by invoking dry dissipationless mergers, since dissipation tends to reduce the sizes of galaxies, and wet mergers which result in star formation would tend to increase the scatter in luminosity at fixed size and velocity dispersion. Furthermore, BCGs define the same g-r color-magnitude relation as the bulk of the early-type population. If BCGs formed from dry mergers, then BCG progenitors must have been red for their magnitudes, suggesting that they hosted older stellar populations than typical for their luminosities. Our findings have two other consequences. First, the R_e-L relation of the early-type galaxy population as a whole (i.e., normal plus BCG) exhibits some curvature. Some of this curvature must be a consequence of the fact that an increasing fraction of the most luminous galaxies are BCGs. The second consequence is suggested by the fact that, despite following a steeper size-luminosity relation, BCGs tend to define a tight relation between dynamical mass R_e sigma^2/G and luminosity. As consequence, we find that BCGs define a shallower sigma-L relation than the bulk of the early-type galaxy population.Comment: 16 pages, 16 figures, AJ in pres

    Overview of the Kepler Science Processing Pipeline

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    The Kepler Mission Science Operations Center (SOC) performs several critical functions including managing the ~156,000 target stars, associated target tables, science data compression tables and parameters, as well as processing the raw photometric data downlinked from the spacecraft each month. The raw data are first calibrated at the pixel level to correct for bias, smear induced by a shutterless readout, and other detector and electronic effects. A background sky flux is estimated from ~4500 pixels on each of the 84 CCD readout channels, and simple aperture photometry is performed on an optimal aperture for each star. Ancillary engineering data and diagnostic information extracted from the science data are used to remove systematic errors in the flux time series that are correlated with these data prior to searching for signatures of transiting planets with a wavelet-based, adaptive matched filter. Stars with signatures exceeding 7.1 sigma are subjected to a suite of statistical tests including an examination of each star's centroid motion to reject false positives caused by background eclipsing binaries. Physical parameters for each planetary candidate are fitted to the transit signature, and signatures of additional transiting planets are sought in the residual light curve. The pipeline is operational, finding planetary signatures and providing robust eliminations of false positives.Comment: 8 pages, 3 figure

    Development of the designed ankyrin repeat protein (DARPin) G3 for HER2 molecular imaging

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    s funded by the Seventh Framework Programme (FP7) for HER Imaging and Molecular Interaction Mapping in Breast Cancer (Imagint EC grant 259881) and the Breast Cancer Campaign. The research was supported by the National Institute for Health Research University College London Hospitals Biomedical Research Centre

    Primordial Non-Gaussianity and Extreme-Value Statistics of Galaxy Clusters

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    What is the size of the most massive object one expects to find in a survey of a given volume? In this paper, we present a solution to this problem using Extreme-Value Statistics, taking into account primordial non-Gaussianity and its effects on the abundance and the clustering of rare objects. We calculate the probability density function (pdf) of extreme-mass clusters in a survey volume, and show how primordial non-Gaussianity shifts the peak of this pdf. We also study the sensitivity of the extreme-value pdfs to changes in the mass functions, survey volume, redshift coverage and the normalization of the matter power spectrum, {\sigma}_8. For 'local' non-Gaussianity parametrized by f_NL, our correction for the extreme-value pdf due to the bias is important when f_NL > O(100), and becomes more significant for wider and deeper surveys. Applying our formalism to the massive high-redshift cluster XMMUJ0044.0-2-33, we find that its existence is consistent with f_NL = 0, although the conclusion is sensitive to the assumed values of the survey area and {\sigma}_8. We also discuss the convergence of the extreme-value distribution to one of the three possible asymptotic forms, and argue that the convergence is insensitive to the presence of non-Gaussianity.Comment: Revised version, 20 pages, 10 figures. Major improvement in the treatment of non-Gaussian bias. Previous claim of large f_NL associated with the cluster is no longer supporte

    The Multiscale Morphology Filter: Identifying and Extracting Spatial Patterns in the Galaxy Distribution

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    We present here a new method, MMF, for automatically segmenting cosmic structure into its basic components: clusters, filaments, and walls. Importantly, the segmentation is scale independent, so all structures are identified without prejudice as to their size or shape. The method is ideally suited for extracting catalogues of clusters, walls, and filaments from samples of galaxies in redshift surveys or from particles in cosmological N-body simulations: it makes no prior assumptions about the scale or shape of the structures.}Comment: Replacement with higher resolution figures. 28 pages, 17 figures. For Full Resolution Version see: http://www.astro.rug.nl/~weygaert/tim1publication/miguelmmf.pd

    Active Mg Estimation Using Thermal Analysis: A Rapid Method to Control Nodularity in Ductile Cast Iron Production

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    Appropriate nodularity in ductile iron castings is strongly associated with the presence of high enough not combined Mg dissolved in the melt to cast. However, the residual Mg which is commonly measured for production control accounts for both dissolved Mg and Mg combined as oxides and sulfides. To account for the uncertainties associated with such a control, it is quite usual to over treat the melt with the risk of porosity appearance. A new methodology based on thermal analysis has been developed in the present work so as to estimate the amount of free Mg dissolved in the melt ready for pouring. A combination of Te mixture and a new “reactive mixture” composed of sulfur plus a commercial inoculant has been prepared for this purpose. This reactive mixture is able to transform the magnesium remaining dissolved in the melt to combined forms of this element. Experiments performed both during start of production (when Mg overtreatment is usual) and during normal mass production indicate that important variations of free Mg occur without relevant changes in residual Mg content as determined by spectrometry. The method developed in the present work has shown to be highly effective to detect those melt batches where active Mg content is not high enough for guaranteeing a correct nodularity of castings. Selection of proper active Mg thresholds and a correct inoculation process are critical to avoid “false”-negative results when using this new method
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