40,230 research outputs found
ANXIOLYTIC AND ANTICONVULSANT ACTIVITY OF ALCOHOLIC EXTRACT OF HEART WOOD OF CEDRUS DEODARA ROXB IN RODENTS
The present study was undertaken to evaluate the anxiolytic and anti-convulsant activityof the alcoholic extract of heart wood of Cedrus deodara (ALCD). 50,100 and 200 mg/kg ofalcoholic extract of Cedrus deodara (ALCD) were tested for its anxiolytic and anticonvulsantactivity. Elevated plus maze model (EPM), Actophotometre, Light-dark model were used fortesting anxiolytic activity and Pentylene tetrazole (PTZ) induced convulsions and Maximalelectro shock (MES) induced convulsions models in mice were used for the assessment of itsanticonvulsant activity, Pretreatment with ALCD and estimation of GABA in rat brain tissuesalso performed to study the effect of ALCD (30, 100 mg/kg) on GABA levels of brain. InActophotometre test, higher doses (100 and 200mg/kg) of ALCD has showed significant CNSdepression by reducing locomotor activity in mice. In EPM the 100 and 200mg/kg of ALCDhas increased the time spent in the open arm and decreased time spent in the closed arm. InLight-dark model the 100 and 200mg/kg of ALCD has showed significant increase in the timespent in light zone when compare to the dark zone. In PTZ induced convulsions model 100 and200 mg/kg of ALCD has increased the onset of clonus and tonic seizures
Nuclear forward scattering in particulate matter: dependence of lineshape on particle size distribution
In synchrotron Moessbauer spectroscopy, the nuclear exciton polariton
manifests itself in the lineshape of the spectra of nuclear forward scattering
(NFS) Fourier-transformed from time domain to frequency domain. This lineshape
is generally described by the convolution of two intensity factors. One of them
is Lorentzian related to free decay. We derived the expressions for the second
factor related to Frenkel exciton polariton effects at propagation of
synchrotron radiation in Moessbauer media. Parameters of this Frenkelian shape
depend on the spatial configuration of Moessbauer media. In a layer of uniform
thickness, this factor is found to be a simple hypergeometric function. Next,
we consider the particles spread over a 2D surface or diluted in non-Moessbauer
media to exclude an overlap of ray shadows by different particles. Deconvolving
the purely polaritonic component of linewidths is suggested as a simple
procedure sharpening the experimental NFS spectra in frequency domain. The
lineshapes in these sharpened spectra are theoretically expressed via the
parameters of the particle size distributions (PSD). Then, these parameters are
determined through least-squares fitting of the line shapes.Comment: 13 pages, 12 figure
Bayesian computation for contingency tables with incomplete cell-counts
This article studies Bayesian analysis of contingency tables (or multinomial data) where the cell counts are not fully observed due to reasons such as nonresponse and misclassification, and derives the posterior distributions of the unknown cell probabilities in terms of various types of generalized Dirichlet distributions. For some special situations such as grouped and nested Dirichlet distributions, the posterior means of the unknown cell probabilities can be obtained in closed form by using inverse Bayes formulae and/or stochastic representation. When closed-form expressions do not exist, we suggest using importance sampling with a feasible proposal density to approximately compute the posterior quantities, and propose a procedure for choosing an effective proposal density. Applications are illustrated by sample surveys with nonresponse, crime survey data, death penalty attitude data, and misclassified multinomial data.published_or_final_versio
The host galaxies of luminous radio-quiet quasars
We present the results of a deep K-band imaging study which reveals the host
galaxies around a sample of luminous radio-quiet quasars. The K-band images,
obtained at UKIRT, are of sufficient quality to allow accurate modelling of the
underlying host galaxy. Initially, the basic structure of the hosts is revealed
using a modified Clean deconvolution routine optimised for this analysis. 2 of
the 14 quasars are shown to have host galaxies with violently disturbed
morphologies which cannot be modelled by smooth elliptical profiles. For the
remainder of our sample, 2D models of the host and nuclear component are fitted
to the images using the chi-squared statistic to determine goodness of fit.
Host galaxies are detected around all of the quasars. The reliability of the
modelling is extensively tested, and we find the host luminosity to be well
constrained for 9 quasars. The derived average K-band absolute K-corrected host
galaxy magnitude for these luminous radio-quiet quasars is =-25.15+/-0.04,
slightly more luminous than an L* galaxy. The spread of derived host galaxy
luminosities is small, although the spread of nuclear-to-host ratios is not.
These host luminosities are shown to be comparable to those derived from
samples of quasars of lower total luminosity and we conclude that there is no
correlation between host and nuclear luminosity for these quasars.
Nuclear-to-host ratios break the lower limit previously suggested from studies
of lower nuclear luminosity quasars and Seyfert galaxies. Morphologies are less
certain but, on the scales probed by these images, some hosts appear to be
dominated by spheroids but others appear to have disk-dominated profiles.Comment: 16 pages, 8 figures, revised version to be published in MNRA
FooPar: A Functional Object Oriented Parallel Framework in Scala
We present FooPar, an extension for highly efficient Parallel Computing in
the multi-paradigm programming language Scala. Scala offers concise and clean
syntax and integrates functional programming features. Our framework FooPar
combines these features with parallel computing techniques. FooPar is designed
modular and supports easy access to different communication backends for
distributed memory architectures as well as high performance math libraries. In
this article we use it to parallelize matrix matrix multiplication and show its
scalability by a isoefficiency analysis. In addition, results based on a
empirical analysis on two supercomputers are given. We achieve close-to-optimal
performance wrt. theoretical peak performance. Based on this result we conclude
that FooPar allows to fully access Scala's design features without suffering
from performance drops when compared to implementations purely based on C and
MPI
Nernst branes from special geometry
We construct new black brane solutions in gauged
supergravity with a general cubic prepotential, which have entropy density
as and thus satisfy the Nernst Law. By using
the real formulation of special geometry, we are able to obtain analytical
solutions in closed form as functions of two parameters, the temperature
and the chemical potential . Our solutions interpolate between
hyperscaling violating Lifshitz geometries with at the
horizon and at infinity. In the zero temperature limit,
where the entropy density goes to zero, we recover the extremal Nernst branes
of Barisch et al, and the parameters of the near horizon geometry change to
.Comment: 37 pages. v2: numerical pre-factors of scalar fields q_A corrected in
Section 3. No changes to conclusions. References adde
Wavelet transform-based de-noising for two-photon imaging of synaptic Ca2+ transients.
PublishedJournal ArticleResearch Support, Non-U.S. Gov'tThis is an open access article.Postsynaptic Ca(2+) transients triggered by neurotransmission at excitatory synapses are a key signaling step for the induction of synaptic plasticity and are typically recorded in tissue slices using two-photon fluorescence imaging with Ca(2+)-sensitive dyes. The signals generated are small with very low peak signal/noise ratios (pSNRs) that make detailed analysis problematic. Here, we implement a wavelet-based de-noising algorithm (PURE-LET) to enhance signal/noise ratio for Ca(2+) fluorescence transients evoked by single synaptic events under physiological conditions. Using simulated Ca(2+) transients with defined noise levels, we analyzed the ability of the PURE-LET algorithm to retrieve the underlying signal. Fitting single Ca(2+) transients with an exponential rise and decay model revealed a distortion of τ(rise) but improved accuracy and reliability of τ(decay) and peak amplitude after PURE-LET de-noising compared to raw signals. The PURE-LET de-noising algorithm also provided a ∼30-dB gain in pSNR compared to ∼16-dB pSNR gain after an optimized binomial filter. The higher pSNR provided by PURE-LET de-noising increased discrimination accuracy between successes and failures of synaptic transmission as measured by the occurrence of synaptic Ca(2+) transients by ∼20% relative to an optimized binomial filter. Furthermore, in comparison to binomial filter, no optimization of PURE-LET de-noising was required for reducing arbitrary bias. In conclusion, the de-noising of fluorescent Ca(2+) transients using PURE-LET enhances detection and characterization of Ca(2+) responses at central excitatory synapses.C.M.T. and J.R.M. were supported by the Wellcome Trust, and K.T.-A. was supported by grant No. EP/I018638/1 from the Engineering and Physical Sciences Research Council
Process monitoring in intensive care with the use of cumulative expected minus observed mortality and risk-adjusted p charts
INTRODUCTION: A health care system is a complex adaptive system. The effect of a single intervention, incorporated into a complex clinical environment, may be different from that expected. A national database such as the Intensive Care National Audit & Research Centre (ICNARC) Case Mix Programme in the UK represents a centralised monitoring, surveillance and reporting system for retrospective quality and comparative audit. This can be supplemented with real-time process monitoring at a local level for continuous process improvement, allowing early detection of the impact of both unplanned and deliberately imposed changes in the clinical environment. METHODS: Demographic and UK Acute Physiology and Chronic Health Evaluation II (APACHE II) data were prospectively collected on all patients admitted to a UK regional hospital between 1 January 2003 and 30 June 2004 in accordance with the ICNARC Case Mix Programme. We present a cumulative expected minus observed (E-O) plot and the risk-adjusted p chart as methods of continuous process monitoring. We describe the construction and interpretation of these charts and show how they can be used to detect planned or unplanned organisational process changes affecting mortality outcomes. RESULTS: Five hundred and eighty-nine adult patients were included. The overall death rate was 0.78 of predicted. Calibration showed excess survival in ranges above 30% risk of death. The E-O plot confirmed a survival above that predicted. Small transient variations were seen in the slope that could represent random effects, or real but transient changes in the quality of care. The risk-adjusted p chart showed several observations below the 2 SD control limits of the expected mortality rate. These plots provide rapid analysis of risk-adjusted performance suitable for local application and interpretation. The E-O chart provided rapid easily visible feedback of changes in risk-adjusted mortality, while the risk-adjusted p chart allowed statistical evaluation. CONCLUSION: Local analysis of risk-adjusted mortality data with an E-O plot and a risk-adjusted p chart is feasible and allows the rapid detection of changes in risk-adjusted outcome of intensive care patients. This complements the centralised national database, which is more archival and comparative in nature
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