1,080 research outputs found
On the Cosmic Evolution of Fe/Mg in QSO Absorption Line Systems
We investigate the variation of the ratio of the equivalent widths of the
FeII2600 line to the MgII2796,2803 doublet as a
function of redshift in a large sample of absorption lines drawn from the
JHU-SDSS Absorption Line Catalog. We find that despite large scatter, the
observed ratio shows a trend where the equivalent width ratio
decreases monotonically with
increasing redshift over the range . Selecting the
subset of absorbers where the signal-to-noise ratio of the MgII equivalent
width is 3 and modeling the equivalent width ratio
distribution as a gaussian, we find that the mean of the gaussian distribution
varies as . We discuss various possible
reasons for the trend. A monotonic trend in the Fe/Mg abundance ratio is
predicted by a simple model where the abundances of Mg and Fe in the absorbing
clouds are assumed to be the result of supernova ejecta and where the cosmic
evolution in the SNIa and core-collapse supernova rates is related to the
cosmic star-formation rate. If the trend in reflects the
evolution in the abundances, then it is consistent with the predictions of the
simple model.Comment: 10 pages, 4 figures, final version published in MNRA
Reliability of clinical methods in evaluating patellofemoral pain syndrome with malalignment
Background: Diagnosis of patellofemroal pain syndrome has been challenging due to lack of clinical test with better sensitivity and specificity, axial imaging has been considered as the standard modality for evaluation. Patients with anterior knee pain because of patellofemoral pain syndrome can be sub-grouped as those with or without radiological positive parameter for patellar maltracking. The aim of the present study was to evaluate reliability of clinical tests in two subgroups of patients presenting with patellofemoral pain syndrome.Methods: 45 knees with anterior knee pain without any episode of patellar instability were evaluated clinically using four standard tests (patellar apprehension test (PAT), eccentric step test (EST), active instability test (AIT) and Waldron’s test. On the basis of CT scan finding (at least one positive radiological parameter of instability) 28 knees were categorized in Group A (potential patellar instability group) and 17 knees in Group B (PFPS).Results: All patients with 3 or more than three clinical test positive were cases with potential patellofemroal instability except two. Whereas other true patellofemroal pain patients all except 2 were have less than 3 positive clinical tests. Conclusions: Clinical test have more diagnostic accuracy in evaluating anterior knee pain due to potential patellofemroal instability in comparison to patellofemroal pain without radiological instability
Serendipitously Detected Galaxies in the Hubble Deep Field
We present a catalog of 74 galaxies detected serendipitously during a
campaign of spectroscopic observations of the Hubble Deep Field North (HDF) and
its environs. Among the identified objects are five candidate Ly-alpha emitters
at z > 5, a galaxy cluster at z = 0.85, and a Chandra source with a heretofore
undetermined redshift of z = 2.011. We report redshifts for 25 galaxies in the
central HDF, 13 of which had no prior published spectroscopic redshift. Of the
remaining 49 galaxies, 30 are located in the single-orbit HDF Flanking Fields.
We discuss the redshift distribution of the serendipitous sample, which
contains galaxies in the range 0.10 < z < 5.77 with a median redshift of z =
0.85, and we present strong evidence for redshift clustering. By comparing our
spectroscopic redshifts to optical/IR photometric studies of the HDF, we find
that photometric redshifts are in most cases capable of producing reasonable
predictions of galaxy redshifts. Finally, we estimate the line-of-sight
velocity dispersion and the corresponding mass and expected X-ray luminosity of
the galaxy cluster, we present strong arguments for interpreting the Chandra
source as an obscured AGN, and we discuss in detail the spectrum of one of the
candidate z > 5 Ly-alpha emitters.Comment: 18 pages, 9 figures, accepted for publication in the Astronomical
Journa
Trans-Planckian censorship and other swampland bothers addressed in warm inflation
The implications of the recently proposed Trans-Planckian censorship
conjecture (TCC) are analyzed in the context of warm inflation. It is found
that for a single-stage accelerated expansion the constraints imposed by the
censorship are roughly the same as for cold inflation. Next, we study how a
two-stage inflationary expansion with an intermediate radiation-dominated era
can alleviate the bounds imposed by the censorship. For a demonstrative toy
model we found , but can be for a weaker form of TCC
for the later stages of expansion, while still satisfying the other swampland
conditions.Comment: 11 pages, 2 figures. In Press Physical Review
The Star Formation Histories of z ~ 2 Dust-obscured Galaxies and Submillimeter-selected Galaxies
The Spitzer Space Telescope has identified a population of ultraluminous infrared galaxies (ULIRGs) at z ~ 2 that may play an important role in the evolution of massive galaxies. We measure the stellar masses (M_*) of two populations of Spitzer-selected ULIRGs that have extremely red R – [24] colors (dust-obscured galaxies, or DOGs) and compare our results with submillimeter-selected galaxies (SMGs). One set of 39 DOGs has a local maximum in their mid-infrared (mid-IR) spectral energy distribution (SED) at rest frame 1.6 μm associated with stellar emission ("bump DOGs"), while the other set of 51 DOGs have power-law mid-IR SEDs that are typical of obscured active galactic nuclei ("power-law DOGs"). We measure M_* by applying Charlot & Bruzual stellar population synthesis models to broadband photometry in the rest-frame ultraviolet, optical, and near-infrared of each of these populations. Assuming a simple stellar population and a Chabrier initial mass function, we find that power-law DOGs and bump DOGs are on average a factor of 2 and 1.5 more massive than SMGs, respectively (median and inter-quartile M_* values for SMGs, bump DOGs, and power-law DOGs are log(M_*/M_☉) = 10.42^(+0.42)_(–0.36), 10.62^(+0.36)_(–0.32), and 10.71^(+0.40)_(–0.34), respectively). More realistic star formation histories drawn from two competing theories for the nature of ULIRGs at z ~ 2 (major merger versus smooth accretion) can increase these mass estimates by up to 0.5 dex. A comparison of our stellar masses with the instantaneous star formation rate (SFR) in these z ~ 2 ULIRGs provides a preliminary indication supporting high SFRs for a given M_*, a situation that arises more naturally in major mergers than in smooth accretion-powered systems
WNK Kinase Signaling in Ion Homeostasis and Human Disease
This is the author accepted manuscript. The final version is available from Elsevier via the DOI in this record.WNK kinases, along with their upstream regulators (CUL3/KLHL3) and downstream targets (the SPAK/OSR1 kinases and the cation-Cl- cotransporters [CCCs]), comprise a signaling cascade essential for ion homeostasis in the kidney and nervous system. Recent work has furthered our understanding of the WNKs in epithelial transport, cell volume homeostasis, and GABA signaling, and uncovered novel roles for this pathway in immune cell function and cell proliferation.This work was supported by a NIHNRCDP grant (K.T.K.), Simons Foundation grant #400947 (K.T.K.), March of Dimes Basil O’Connor Award (K.T.K.), and NIH grant DK93501 to E.D
Microwave spin resonance investigation on the effect of the post-processing annealing of CoFe2O4 nanoparticles
A novel investigation on the finite-size effects on the spin resonance properties of cobalt ferrite (CoFe2O4) nanoparticles has been performed using a room temperature ferromagnetic resonance (FMR) technique. A single broad spectrum was obtained for the CoFe2O4 nanoparticle samples, which indicated that all the samples were showing ferromagnetic characteristics. An asymmetric FMR line shape with a hefty trailing section was obtained due to the high magneto-crystalline anisotropy in CoFe2O4 nanoparticles, which changed with the size distribution. The resonance field for the samples shifted to a higher value due to the increase in the magneto-crystalline anisotropy in the CoFe2O4 nanoparticles with an increase in size. A systematic change in the resonance field and line width was observed with the change in the size distribution of the particles. Initially, it decreased with an increase in the size of the particles and increased after the critical size range. The critical size range is the imprint of the shift of the magnetic domain from a single domain to multi domain. The line width increased at higher annealing temperatures due to the enhancement in the dipole-dipole interaction, which led to a higher spin concentration as well as magneto-crystalline anisotropy. Furthermore, the saturation magnetization (M-s) as well as 'M-r/M-s' increased from 37.7 to 71.4 emu g(-1) and 0.06 to 0.31, respectively. The highest coercivity (750.9 Oe) and anisotropy constant (4.62 x 10(4) erg cm(-3)) were found for the sample annealed at 700 degrees C, which can be corroborated by the literature as the critical annealing temperature at which CoFe2O4 nanoparticles shift from single domain nanoparticles to multi-domain nanoparticles. Post-processing annealing is critical in advanced processing techniques and spin dynamics plays a vital role in various interdisciplinary areas of applications
Association Between Health Literacy, Electronic Health Literacy, Disease-Specific Knowledge, and Health-Related Quality of Life Among Adults With Chronic Obstructive Pulmonary Disease: Cross-Sectional Study
Background: Despite the relatively high prevalence of low health literacy among individuals living with chronic obstructive pulmonary disease (COPD), limited empirical attention has been paid to the cognitive and health literacy–related skills that can uniquely influence patients’ health-related quality of life (HRQoL) outcomes.
Objective: The aim of this study was to examine how health literacy, electronic health (eHealth) literacy, and COPD knowledge are associated with both generic and lung-specific HRQoL in people living with COPD.
Methods: Adults from the COPD Foundation’s National Research Registry (n=174) completed a cross-sectional Web-based survey that assessed sociodemographic characteristics, comorbidity status, COPD knowledge, health literacy, eHealth literacy, and generic/lung-specific HRQoL. Hierarchical linear regression models were tested to examine the roles of health literacy and eHealth literacy on generic (model 1) and lung-specific (model 2) HRQoL, after accounting for socioeconomic and comorbidity covariates. Spearman rank correlations examined associations between ordinal HRQoL items and statistically significant hierarchical predictor variables.
Results: After adjusting for confounding factors, health literacy, eHealth literacy, and COPD knowledge accounted for an additional 9% of variance in generic HRQoL (total adjusted R2=21%; F9,164=6.09, P<.001). Health literacy (b=.08, SE 0.02, 95% CI 0.04-0.12) was the only predictor positively associated with generic HRQoL (P<.001). Adding health literacy, eHealth literacy, and COPD knowledge as predictors explained an additional 7.40% of variance in lung-specific HRQoL (total adjusted R2=26.4%; F8,161=8.59, P<.001). Following adjustment for covariates, both health literacy (b=2.63, SE 0.84, 95% CI 0.96-4.29, P<.001) and eHealth literacy (b=1.41, SE 0.67, 95% CI 0.09-2.73, P<.001) were positively associated with lung-specific HRQoL. Health literacy was positively associated with most lung-specific HRQoL indicators (ie, cough frequency, chest tightness, activity limitation at home, confidence leaving home, sleep quality, and energy level), whereas eHealth literacy was positively associated with 5 of 8 (60%) lung-specific HRQoL indicators. Upon controlling for confounders, COPD knowledge (b=−.56, SE 0.29, 95% CI −1.22 to −0.004, P<.05) was inversely associated with lung-specific HRQoL.
Conclusions: Health literacy, but not eHealth literacy, was positively associated with generic HRQoL. However, both health literacy and eHealth literacy were positively associated with lung-specific HRQoL, with higher COPD knowledge indicative of lower lung-specific HRQoL. These results confirm the importance of considering health and eHealth literacy levels when designing patient education programs for people living with COPD. Future research should explore the impact of delivering interventions aimed at improving eHealth and health literacy among patients with COPD, particularly when disease self-management goals are to enhance HRQoL
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