141 research outputs found
Estimated Time for Occurrence of Smoking-Related Consequences among Pregnant and Non-Pregnant Women
Objectives: To study time estimates by women smokers for when smoking-related consequences will occur given continuing or quitting smoking. The relationship of these estimates to pregnancy and intent to quit smoking was also investigated. Methods: Over a two-week period, eighty women, selected to constitute four subgroups formed by pregnant vs. non-pregnant and trying vs. not trying to quit smoking, rated times at which they would expect smoking-related consequences to occur given continuing or quitting smoking. Results: Somatic health consequences were estimated to occur later than consequences related to mood and social relations. All consequences were estimated to occur later given quitting smoking. Pregnancy had an effect on the estimated time that consequences would occur, with pregnant women estimating earlier occurrence of consequences related to mood and social relations than non-pregnant women did. Conclusion: Health messages should stress consequences for somatic health in quitting smoking, since outcomes later in time might have too low a value to exert a positive effect on decisions to quit smoking
The VLT-FLAMES Tarantula Survey III: A very massive star in apparent isolation from the massive cluster R136
VFTS 682 is located in an active star-forming region, at a projected distance
of 29 pc from the young massive cluster R136 in the Tarantula Nebula of the
Large Magellanic Cloud. It was previously reported as a candidate young stellar
object, and more recently spectroscopically revealed as a hydrogen-rich
Wolf-Rayet (WN5h) star. Our aim is to obtain the stellar properties, such as
its intrinsic luminosity, and to investigate the origin of VFTS 682. To this
purpose, we model optical spectra from the VLT-FLAMES Tarantula Survey with the
non-LTE stellar atmosphere code CMFGEN, as well as the spectral energy
distribution from complementary optical and infrared photometry. We find the
extinction properties to be highly peculiar (RV ~4.7), and obtain a
surprisingly high luminosity log(L/Lsun) = 6.5 \pm 0.2, corresponding to a
present-day mass of ~150Msun. The high effective temperature of 52.2 \pm 2.5kK
might be explained by chemically homogeneous evolution - suggested to be the
key process in the path towards long gamma-ray bursts. Lightcurves of the
object show variability at the 10% level on a timescale of years. Such changes
are unprecedented for classical Wolf-Rayet stars, and are more reminiscent of
Luminous Blue Variables. Finally, we discuss two possibilities for the origin
of VFTS 682: (i) the star either formed in situ, which would have profound
implications for the formation mechanism of massive stars, or (ii) VFTS 682 is
a slow runaway star that originated from the dense cluster R136, which would
make it the most massive runaway known to date.Comment: 5 pages, 5 figures, accepted by A&A Letter
The Group B Streptococcal surface antigen I/II protein, BspC, interacts with host vimentin to promote adherence to brain endothelium and inflammation during the pathogenesis of meningitis
Streptococcus agalactiae (Group B Streptococcus, GBS) normally colonizes healthy adults but can cause invasive disease, such as meningitis, in the newborn. To gain access to the central nervous system, GBS must interact with and penetrate brain or meningeal blood vessels; however, the exact mechanisms are still being elucidated. Here, we investigate the contribution of BspC, an antigen I/II family adhesin, to the pathogenesis of GBS meningitis. Disruption of the bspC gene reduced GBS adherence to human cerebral microvascular endothelial cells (hCMEC), while heterologous expression of BspC in non-adherent Lactococcus lactis conferred bacterial attachment. In a murine model of hematogenous meningitis, mice infected with ÎbspC mutants exhibited lower mortality as well as decreased brain bacterial counts and inflammatory infiltrate compared to mice infected with WT GBS strains. Further, BspC was both necessary and sufficient to induce neutrophil chemokine expression. We determined that BspC interacts with the host cytoskeleton component vimentin and confirmed this interaction using a bacterial two-hybrid assay, microscale thermophoresis, immunofluorescent staining, and imaging flow cytometry. Vimentin null mice were protected from WT GBS infection and also exhibited less inflammatory cytokine production in brain tissue. These results suggest that BspC and the vimentin interaction is critical for the pathogenesis of GBS meningitis
The Effects of Two Types of Sleep Deprivation on Visual Working Memory Capacity and Filtering Efficiency
Sleep deprivation has adverse consequences for a variety of cognitive functions. The exact effects of sleep deprivation, though, are dependent upon the cognitive process examined. Within working memory, for example, some component processes are more vulnerable to sleep deprivation than others. Additionally, the differential impacts on cognition of different types of sleep deprivation have not been well studied. The aim of this study was to examine the effects of one night of total sleep deprivation and 4 nights of partial sleep deprivation (4 hours in bed/night) on two components of visual working memory: capacity and filtering efficiency. Forty-four healthy young adults were randomly assigned to one of the two sleep deprivation conditions. All participants were studied: 1) in a well-rested condition (following 6 nights of 9 hours in bed/night); and 2) following sleep deprivation, in a counter-balanced order. Visual working memory testing consisted of two related tasks. The first measured visual working memory capacity and the second measured the ability to ignore distractor stimuli in a visual scene (filtering efficiency). Results showed neither type of sleep deprivation reduced visual working memory capacity. Partial sleep deprivation also generally did not change filtering efficiency. Total sleep deprivation, on the other hand, did impair performance in the filtering task. These results suggest components of visual working memory are differentially vulnerable to the effects of sleep deprivation, and different types of sleep deprivation impact visual working memory to different degrees. Such findings have implications for operational settings where individuals may need to perform with inadequate sleep and whose jobs involve receiving an array of visual information and discriminating the relevant from the irrelevant prior to making decisions or taking actions (e.g., baggage screeners, air traffic controllers, military personnel, health care providers)
Nitrogen line spectroscopy in O-stars -- II. Surface nitrogen abundances for O-stars in the Large Magellanic Cloud
This is the second paper in a series aiming at the analysis of nitrogen
abundances in O-type stars, to enable further constraints on the early
evolution of massive stars. We investigate the NIV lambda4058 emission line
formation, provide nitrogen abundances for a substantial O-star sample in the
LMC, and compare our findings with recent predictions from stellar evolutionary
models. Stellar and wind parameters are determined by line profile fitting of
hydrogen, helium and nitrogen lines, based on synthetic spectra calculated by
FASTWIND. We derive nitrogen abundances for 20 O- and 5 B-stars, by analyzing
all nitrogen lines present in the available optical spectra. The dominating
process responsible for emission at NIV lambda4058 in O-stars is the strong
depopulation of the lower level of the transition, which increases as a
function of Mdot. Unlike the NIII triplet emission, resonance lines do not play
a role for typical mass-loss rates and below. The bulk of our sample O-stars
seems to be strongly nitrogen-enriched, and a clear correlation of nitrogen and
helium enrichment is found. By comparing the nitrogen abundances as a function
of vsini ('Hunter-plot') with tailored evolutionary calculations, we identify a
considerable number of highly enriched objects at low rotation. Due to the low
initial abundance, the detection of strong Nitrogen enrichment in the bulk of
O-stars indicates that efficient mixing takes place already during the very
early phases of stellar evolution of LMC O-stars.Comment: Main paper: 23 pages, 9 figures. Appendix: 17 pages, 32 figures.
Accepted by Astronomy & Astrophysic
Computational Bacterial Genome-Wide Analysis of Phylogenetic Profiles Reveals Potential Virulence Genes of Streptococcus agalactiae
The phylogenetic profile of a gene is a reflection of its evolutionary history
and can be defined as the differential presence or absence of a gene in a set of
reference genomes. It has been employed to facilitate the prediction of gene
functions. However, the hypothesis that the application of this concept can also
facilitate the discovery of bacterial virulence factors has not been fully
examined. In this paper, we test this hypothesis and report a computational
pipeline designed to identify previously unknown bacterial virulence genes using
group B streptococcus (GBS) as an example. Phylogenetic profiles of all GBS
genes across 467 bacterial reference genomes were determined by
candidate-against-all BLAST searches,which were then used to identify candidate
virulence genes by machine learning models. Evaluation experiments with known
GBS virulence genes suggested good functional and model consistency in
cross-validation analyses (areas under ROC curve, 0.80 and 0.98 respectively).
Inspection of the top-10 genes in each of the 15 virulence functional groups
revealed at least 15 (of 119) homologous genes implicated in virulence in other
human pathogens but previously unrecognized as potential virulence genes in GBS.
Among these highly-ranked genes, many encode hypothetical proteins with possible
roles in GBS virulence. Thus, our approach has led to the identification of a
set of genes potentially affecting the virulence potential of GBS, which are
potential candidates for further in vitro and in
vivo investigations. This computational pipeline can also be
extended to in silico analysis of virulence determinants of
other bacterial pathogens
A Program for At-Risk High School Students Informed by Evolutionary Science
Improving the academic performance of at-risk high school students has proven difficult, often calling for an extended day, extended school year, and other expensive measures. Here we report the results of a program for at-risk 9th and 10th graders in Binghamton, New York, called the Regents Academy that takes place during the normal school day and year. The design of the program is informed by the evolutionary dynamics of cooperation and learning, in general and for our species as a unique product of biocultural evolution. Not only did the Regents Academy students outperform their comparison group in a randomized control design, but they performed on a par with the average high school student in Binghamton on state-mandated exams. All students can benefit from the social environment provided for at-risk students at the Regents Academy, which is within the reach of most public school districts
The influence of MRI scan position on patients with oropharyngeal cancer undergoing radical radiotherapy
Identification and reconstruction of low-energy electrons in the ProtoDUNE-SP detector
Measurements of electrons from interactions are crucial for the Deep
Underground Neutrino Experiment (DUNE) neutrino oscillation program, as well as
searches for physics beyond the standard model, supernova neutrino detection,
and solar neutrino measurements. This article describes the selection and
reconstruction of low-energy (Michel) electrons in the ProtoDUNE-SP detector.
ProtoDUNE-SP is one of the prototypes for the DUNE far detector, built and
operated at CERN as a charged particle test beam experiment. A sample of
low-energy electrons produced by the decay of cosmic muons is selected with a
purity of 95%. This sample is used to calibrate the low-energy electron energy
scale with two techniques. An electron energy calibration based on a cosmic ray
muon sample uses calibration constants derived from measured and simulated
cosmic ray muon events. Another calibration technique makes use of the
theoretically well-understood Michel electron energy spectrum to convert
reconstructed charge to electron energy. In addition, the effects of detector
response to low-energy electron energy scale and its resolution including
readout electronics threshold effects are quantified. Finally, the relation
between the theoretical and reconstructed low-energy electron energy spectrum
is derived and the energy resolution is characterized. The low-energy electron
selection presented here accounts for about 75% of the total electron deposited
energy. After the addition of lost energy using a Monte Carlo simulation, the
energy resolution improves from about 40% to 25% at 50~MeV. These results are
used to validate the expected capabilities of the DUNE far detector to
reconstruct low-energy electrons.Comment: 19 pages, 10 figure
Impact of cross-section uncertainties on supernova neutrino spectral parameter fitting in the Deep Underground Neutrino Experiment
A primary goal of the upcoming Deep Underground Neutrino Experiment (DUNE) is
to measure the MeV neutrinos produced by a Galactic
core-collapse supernova if one should occur during the lifetime of the
experiment. The liquid-argon-based detectors planned for DUNE are expected to
be uniquely sensitive to the component of the supernova flux, enabling
a wide variety of physics and astrophysics measurements. A key requirement for
a correct interpretation of these measurements is a good understanding of the
energy-dependent total cross section for charged-current
absorption on argon. In the context of a simulated extraction of
supernova spectral parameters from a toy analysis, we investigate the
impact of modeling uncertainties on DUNE's supernova neutrino
physics sensitivity for the first time. We find that the currently large
theoretical uncertainties on must be substantially reduced
before the flux parameters can be extracted reliably: in the absence of
external constraints, a measurement of the integrated neutrino luminosity with
less than 10\% bias with DUNE requires to be known to about 5%.
The neutrino spectral shape parameters can be known to better than 10% for a
20% uncertainty on the cross-section scale, although they will be sensitive to
uncertainties on the shape of . A direct measurement of
low-energy -argon scattering would be invaluable for improving the
theoretical precision to the needed level.Comment: 25 pages, 21 figure
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