3,479 research outputs found
The analysis of spectra of novae taken near maximum
A project to analyze ultraviolet spectra of novae obtained at or near maximum optical light is presented. These spectra are characterized by a relatively cool continuum with superimposed permitted emission lines from ions such as Fe II, Mg II, and Si II. Spectra obtained late in the outburst show only emission lines from highly ionized species and in many cases these are forbidden lines. The ultraviolet data will be used with calculations of spherical, expanding, stellar atmospheres for novae to determine elemental abundances by spectral line synthesis. This method is extremely sensitive to the abundances and completely independent of the nebular analyses usually used to obtain novae abundances
Efeito do espaçamento de plantio e do teor de água na massa específica aparente e massa de mil grãos dos grãos de soja.
Differentiating lower motor neuron syndromes
Lower motor neuron (LMN) syndromes typically present with muscle wasting and weakness and may arise from pathology affecting the distal motor nerve up to the level of the anterior horn cell. A variety of hereditary causes are recognised, including spinal muscular atrophy, distal hereditary motor neuropathy and LMN variants of familial motor neuron disease. Recent genetic advances have resulted in the identification of a variety of disease-causing mutations. Immune-mediated disorders, including multifocal motor neuropathy and variants of chronic inflammatory demyelinating polyneuropathy, account for a proportion of LMN presentations and are important to recognise, as effective treatments are available. The present review will outline the spectrum of LMN syndromes that may develop in adulthood and provide a framework for the clinician assessing a patient presenting with predominantly LMN features
Complex exon-intron marking by histone modifications is not determined solely by nucleosome distribution
It has recently been shown that nucleosome distribution, histone modifications and RNA polymerase II (Pol II) occupancy show preferential association with exons (“exon-intron marking”), linking chromatin structure and function to co-transcriptional splicing in a variety of eukaryotes. Previous ChIP-sequencing studies suggested that these marking patterns reflect the nucleosomal landscape. By analyzing ChIP-chip datasets across the human genome in three cell types, we have found that this marking system is far more complex than previously observed. We show here that a range of histone modifications and Pol II are preferentially associated with exons. However, there is noticeable cell-type specificity in the degree of exon marking by histone modifications and, surprisingly, this is also reflected in some histone modifications patterns showing biases towards introns. Exon-intron marking is laid down in the absence of transcription on silent genes, with some marking biases changing or becoming reversed for genes expressed at different levels. Furthermore, the relationship of this marking system with splicing is not simple, with only some histone modifications reflecting exon usage/inclusion, while others mirror patterns of exon exclusion. By examining nucleosomal distributions in all three cell types, we demonstrate that these histone modification patterns cannot solely be accounted for by differences in nucleosome levels between exons and introns. In addition, because of inherent differences between ChIP-chip array and ChIP-sequencing approaches, these platforms report different nucleosome distribution patterns across the human genome. Our findings confound existing views and point to active cellular mechanisms which dynamically regulate histone modification levels and account for exon-intron marking. We believe that these histone modification patterns provide links between chromatin accessibility, Pol II movement and co-transcriptional splicing
Measurement of Atmospheric Neutrino Oscillations with the ANTARES Neutrino Telescope
The data taken with the ANTARES neutrino telescope from 2007 to 2010, a total
live time of 863 days, are used to measure the oscillation parameters of
atmospheric neutrinos. Muon tracks are reconstructed with energies as low as 20
GeV. Neutrino oscillations will cause a suppression of vertical upgoing muon
neutrinos of such energies crossing the Earth. The parameters determining the
oscillation of atmospheric neutrinos are extracted by fitting the event rate as
a function of the ratio of the estimated neutrino energy and reconstructed
flight path through the Earth. Measurement contours of the oscillation
parameters in a two-flavour approximation are derived. Assuming maximum mixing,
a mass difference of eV is
obtained, in good agreement with the world average value.Comment: 9 pages, 5 figure
a prospective ‘before/after’ cohort study
Objectives Antibiotic resistance has risen dramatically over the past years.
For individual patients, adequate initial antibiotic therapy is essential for
clinical outcome. Computer-assisted decision support systems (CDSSs) are
advocated to support implementation of rational anti-infective treatment
strategies based on guidelines. The aim of this study was to evaluate long-
term effects after implementation of a CDSS. Design This prospective
‘before/after’ cohort study was conducted over four observation periods within
5 years. One preinterventional period (pre) was compared with three
postinterventional periods: directly after intensive implementation efforts
(post1), 2 years (post2) and 3 years (post3) after implementation. Setting
Five anaesthesiological-managed intensive care units (ICU) (one
cardiosurgical, one neurosurgical, two interdisciplinary and one intermediate
care) at a university hospital. Participants Adult patients with an ICU stay
of >48 h were included in the analysis. 1316 patients were included in the
analysis for a total of 12 965 ICU days. Intervention Implementation of a
CDSS. Outcome measures The primary end point was percentage of days with
guideline adherence during ICU treatment. Secondary end points were
antibiotic-free days and all-cause mortality compared for patients with low
versus high guideline adherence. Main results Adherence to guidelines
increased from 61% prior to implementation to 92% in post1, decreased in post2
to 76% and remained significantly higher compared with baseline in post3, with
71% (p=0.178). Additionally, antibiotic-free days increased over study
periods. At all time periods, mortality for patients with low guideline
adherence was higher with 12.3% versus 8% (p=0.014) and an adjusted OR of 1.56
(95% CI 1.05 to 2.31). Conclusions Implementation of computerised regional
adapted guidelines for antibiotic therapy is paralleled with improved
adherence. Even without further measures, adherence stayed high for a longer
period and was paralleled by reduced antibiotic exposure. Improved guideline
adherence was associated with reduced ICU mortality
Status and Recent Results of the Acoustic Neutrino Detection Test System AMADEUS
The AMADEUS system is an integral part of the ANTARES neutrino telescope in
the Mediterranean Sea. The project aims at the investigation of techniques for
acoustic neutrino detection in the deep sea. Installed at a depth of more than
2000m, the acoustic sensors of AMADEUS are based on piezo-ceramics elements for
the broad-band recording of signals with frequencies ranging up to 125kHz.
AMADEUS was completed in May 2008 and comprises six "acoustic clusters", each
one holding six acoustic sensors that are arranged at distances of roughly 1m
from each other. The clusters are installed with inter-spacings ranging from
15m to 340m. Acoustic data are continuously acquired and processed at a
computer cluster where online filter algorithms are applied to select a
high-purity sample of neutrino-like signals. 1.6 TB of data were recorded in
2008 and 3.2 TB in 2009. In order to assess the background of neutrino-like
signals in the deep sea, the characteristics of ambient noise and transient
signals have been investigated. In this article, the AMADEUS system will be
described and recent results will be presented.Comment: 7 pages, 8 figures. Proceedings of ARENA 2010, the 4th International
Workshop on Acoustic and Radio EeV Neutrino Detection Activitie
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