347 research outputs found
Do pediatricians manage influenza differently than internists?
<p>Abstract</p> <p>Background</p> <p>Little is known about how pediatricians or internists manage influenza symptoms. Recent guidelines on antiviral prescribing by the Centers for Disease Control and Prevention (CDC) make almost no distinction between adults and children. Our objective was to describe how pediatricians in two large academic medical institutions manage influenza and compare them to internists.</p> <p>Methods</p> <p>At the end of the 2003–4 influenza season, we conducted a cross sectional on-line survey of physician knowledge, attitudes and practices regarding rapid diagnostic testing and use of antiviral therapy for influenza at two large academic medical centers, one in Massachusetts and the other in Texas. We collected data on self-reported demographics, test use, prescribing practices, and beliefs about influenza and anti-influenza drugs.</p> <p>Results</p> <p>A total of 107 pediatricians and 103 internists completed the survey (response rate of 53%). Compared to internists, pediatricians were more likely to perform rapid testing (74% vs. 47%, p < 0.0001), to use amantadine (88% vs. 48%, p < 0.0001), to restrict their prescribing to high-risk patients (86% vs. 53%, p < 0.0001), and to believe that antiviral therapy could decrease mortality (38% vs. 22%, p = 0.01). Other beliefs about antiviral therapy did not differ statistically between the specialties. Internists were more likely to be unfamiliar with rapid testing or not to have it available.</p> <p>Conclusion</p> <p>Pediatricians and internists manage influenza differently. Evidence-based guidelines addressing the specific concerns of each group would be helpful.</p
Cygnus X-3 with ISO: investigating the wind
We observed the energetic binary Cygnus X-3 in both quiescent and flaring
states between 4 and 16 microns using the ISO satellite. We find that the
quiescent source shows the thermal free-free spectrum typical of a hot, fast
stellar wind, such as from a massive helium star. The quiescent mass-loss rate
due to a spherically symmetric, non-accelerating wind is found to be in the
range 0.4-2.9 x 10E-4 solar masses per year, consistent with other infrared and
radio observations, but considerably larger than the 10E-5 solar masses per
year deduced from both the orbital change and the X-ray column density. There
is rapid, large amplitude flaring at 4.5 and 11.5 microns at the same time as
enhanced radio and X-ray activity, with the infrared spectrum apparently
becoming flatter in the flaring state. We believe non-thermal processes are
operating, perhaps along with enhanced thermal emission.Comment: Accepted for publication in MNRAS, 11 pages, 6 figure
Hepatic FoxOs link insulin signaling with plasma lipoprotein metabolism through an apolipoprotein M/sphingosine-1-phosphate pathway
Multiple beneficial cardiovascular effects of HDL depend on sphingosine-1-phosphate (S1P). S1P associates with HDL by binding to apolipoprotein M (ApoM). Insulin resistance is a major driver of dyslipidemia and cardiovascular risk. However, the mechanisms linking alterations in insulin signaling with plasma lipoprotein metabolism are incompletely understood. The insulin-repressible FoxO transcription factors mediate key effects of hepatic insulin action on glucose and lipoprotein metabolism. This work tested whether hepatic insulin signaling regulates HDL-S1P and aimed to identify the underlying molecular mechanisms. We report that insulin-resistant, nondiabetic individuals had decreased HDL-S1P levels, but no change in total plasma S1P. This also occurred in insulin-resistant db/db mice, which had low ApoM and a specific reduction of S1P in the HDL fraction, with no change in total plasma S1P levels. Using mice lacking hepatic FoxOs (L-FoxO1,3,4), we found that hepatic FoxOs were required for ApoM expression. Total plasma S1P levels were similar to those in controls, but S1P was nearly absent from HDL and was instead increased in the lipoprotein-depleted plasma fraction. This phenotype was restored to normal by rescuing ApoM in L-FoxO1,3,4 mice. Our findings show that insulin resistance in humans and mice is associated with decreased HDL-associated S1P. Our study shows that hepatic FoxO transcription factors are regulators of the ApoM/S1P pathway
Protective Effect of Val129-PrP against Bovine Spongiform Encephalopathy but not Variant Creutzfeldt-Jakob Disease
Bovine spongiform encephalopathy (BSE) is the only known zoonotic prion that causes variant Creutzfeldt-Jakob disease (vCJD) in humans. The major risk determinant for this disease is the polymorphic codon 129 of the human prion protein (Hu-PrP), where either methionine (Met129) or valine (Val129) can be encoded. To date, all clinical and neuropathologically confirmed vCJD cases have been Met129 homozygous, with the exception of 1 recently reported Met/Val heterozygous case. Here, we found that transgenic mice homozygous for Val129 Hu-PrP show severely restricted propagation of the BSE prion strain, but this constraint can be partially overcome by adaptation of the BSE agent to the Met129 Hu-PrP. In addition, the transmission of vCJD to transgenic mice homozygous for Val129 Hu-PrP resulted in a prion with distinct strain features. These observations may indicate increased risk for vCJD secondary transmission in Val129 Hu-PrP–positive humans with the emergence of new strain features
Self-Consistent Thermal Accretion Disk Corona Models for Compact Objects: II. Application to Cygnus X-1
We apply our self-consistent accretion disk corona (ADC) model, with two
different geometries, to the broad-band X-ray spectrum of the black hole
candidate Cygnus X-1. As shown in a companion paper (Dove, Wilms, and
Begelman), models where the Comptonizing medium is a slab surrounding the cold
accretion disk cannot have a temperature higher than about 120 keV for optical
depths greater than 0.2, resulting in spectra that are much softer than the
observed 10-30 keV spectrum of Cyg X-1. In addition, the slab geometry models
predict a substantial ``soft excess'' at low energies, a feature not observed
for Cyg X-1, and Fe K\alpha fluorescence lines that are stronger than observed.
Previous Comptonization models in the literature invoke a slab geometry with
the optical depth \tau_T \gta 0.3 and the coronal temperature T_c \sim 150 keV,
but they are not self-consistent. Therefore, ADC models with a slab geometry
are not appropriate for explaining the X-ray spectrum of Cyg X-1. Models with a
spherical corona and an exterior disk, however, predict much higher
self-consistent coronal temperatures than the slab geometry models. The higher
coronal temperatures are due to the lower amount of reprocessing of coronal
radiation in the accretion disk, giving rise to a lower Compton cooling rate.
Therefore, for the sphere+disk geometry, the predicted spectrum can be hard
enough to describe the observed X-ray continuum of Cyg X-1 while predicting Fe
fluorescence lines having an equivalent width of \sim 40 eV. Our best-fit
parameter values for the sphere+disk geometry are \tau_T \approx 1.5 and T_c
\approx 90 keV.Comment: 13 pages, Latex, 10 .eps figures, uses emulateapj.sty. To be
published in ApJ, October 1, 1997, Vol. 48
A High Statistics Search for Ultra-High Energy Gamma-Ray Emission from Cygnus X-3 and Hercules X-1
We have carried out a high statistics (2 Billion events) search for
ultra-high energy gamma-ray emission from the X-ray binary sources Cygnus X-3
and Hercules X-1. Using data taken with the CASA-MIA detector over a five year
period (1990-1995), we find no evidence for steady emission from either source
at energies above 115 TeV. The derived upper limits on such emission are more
than two orders of magnitude lower than earlier claimed detections. We also
find no evidence for neutral particle or gamma-ray emission from either source
on time scales of one day and 0.5 hr. For Cygnus X-3, there is no evidence for
emission correlated with the 4.8 hr X-ray periodicity or with the occurrence of
large radio flares. Unless one postulates that these sources were very active
earlier and are now dormant, the limits presented here put into question the
earlier results, and highlight the difficulties that possible future
experiments will have in detecting gamma-ray signals at ultra-high energies.Comment: 26 LaTeX pages, 16 PostScript figures, uses psfig.sty to be published
in Physical Review
Whole-Genome Sequencing of Sake Yeast Saccharomyces cerevisiae Kyokai no. 7
The term ‘sake yeast’ is generally used to indicate the Saccharomyces cerevisiae strains that possess characteristics distinct from others including the laboratory strain S288C and are well suited for sake brewery. Here, we report the draft whole-genome shotgun sequence of a commonly used diploid sake yeast strain, Kyokai no. 7 (K7). The assembled sequence of K7 was nearly identical to that of the S288C, except for several subtelomeric polymorphisms and two large inversions in K7. A survey of heterozygous bases between the homologous chromosomes revealed the presence of mosaic-like uneven distribution of heterozygosity in K7. The distribution patterns appeared to have resulted from repeated losses of heterozygosity in the ancestral lineage of K7. Analysis of genes revealed the presence of both K7-acquired and K7-lost genes, in addition to numerous others with segmentations and terminal discrepancies in comparison with those of S288C. The distribution of Ty element also largely differed in the two strains. Interestingly, two regions in chromosomes I and VII of S288C have apparently been replaced by Ty elements in K7. Sequence comparisons suggest that these gene conversions were caused by cDNA-mediated recombination of Ty elements. The present study advances our understanding of the functional and evolutionary genomics of the sake yeast
Search for Anisotropy of Ultra-High Energy Cosmic Rays with the Telescope Array Experiment
We study the anisotropy of Ultra-High Energy Cosmic Ray (UHECR) events
collected by the Telescope Array (TA) detector in the first 40 months of
operation. Following earlier studies, we examine event sets with energy
thresholds of 10 EeV, 40 EeV, and 57 EeV. We find that the distributions of the
events in right ascension and declination are compatible with an isotropic
distribution in all three sets. We then compare with previously reported
clustering of the UHECR events at small angular scales. No significant
clustering is found in the TA data. We then check the events with E>57 EeV for
correlations with nearby active galactic nuclei. No significant correlation is
found. Finally, we examine all three sets for correlations with the large-scale
structure of the Universe. We find that the two higher-energy sets are
compatible with both an isotropic distribution and the hypothesis that UHECR
sources follow the matter distribution of the Universe (the LSS hypothesis),
while the event set with E>10 EeV is compatible with isotropy and is not
compatible with the LSS hypothesis at 95% CL unless large deflection angles are
also assumed. We show that accounting for UHECR deflections in a realistic
model of the Galactic magnetic field can make this set compatible with the LSS
hypothesis.Comment: 10 pages, 9 figure
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