6,199 research outputs found
The Carina Flare: What can fragments in the wall tell us?
CO(J=2--1) and CO(J=2--1) observations of the molecular cloud
G285.90+4.53 (Cloud~16) in the Carina Flare supershell (GSH287+04-17) with the
APEX telescope are presented. With an algorithm DENDROFIND we identify 51
fragments and compute their sizes and masses. We discuss their mass spectrum
and interpret it as being the result of the shell fragmentation process
described by the pressure assisted gravitational instability - PAGI. We
conclude that the explanation of the clump mass function needs a combination of
gravity with pressure external to the shell.Comment: 19 pages, 14 figures, accepted by A&
The Spitzer Local Volume Legacy: Survey Description and Infrared Photometry
The survey description and the near-, mid-, and far-infrared flux properties
are presented for the 258 galaxies in the Local Volume Legacy (LVL). LVL is a
Spitzer Space Telescope legacy program that surveys the local universe out to
11 Mpc, built upon a foundation of ultraviolet, H-alpha, and HST imaging from
11HUGS (11 Mpc H-alpha and Ultraviolet Galaxy Survey) and ANGST (ACS Nearby
Galaxy Survey Treasury). LVL covers an unbiased, representative, and
statistically robust sample of nearby star-forming galaxies, exploiting the
highest extragalactic spatial resolution achievable with Spitzer. As a result
of its approximately volume-limited nature, LVL augments previous Spitzer
observations of present-day galaxies with improved sampling of the
low-luminosity galaxy population. The collection of LVL galaxies shows a large
spread in mid-infrared colors, likely due to the conspicuous deficiency of 8um
PAH emission from low-metallicity, low-luminosity galaxies. Conversely, the
far-infrared emission tightly tracks the total infrared emission, with a
dispersion in their flux ratio of only 0.1 dex. In terms of the relation
between infrared-to-ultraviolet ratio and ultraviolet spectral slope, the LVL
sample shows redder colors and/or lower infrared-to-ultraviolet ratios than
starburst galaxies, suggesting that reprocessing by dust is less important in
the lower mass systems that dominate the LVL sample. Comparisons with
theoretical models suggest that the amplitude of deviations from the relation
found for starburst galaxies correlates with the age of the stellar populations
that dominate the ultraviolet/optical luminosities.Comment: Accepted for publication in ApJ; Figures 1,8,9 provided as jpeg
Differential effects of dietary supplements on metabolomic profile of smokers versus non-smokers.
BackgroundCigarette smoking is well-known to associate with accelerated skin aging as well as cardiovascular disease and lung cancer, in large part due to oxidative stress. Because metabolites are downstream of genetic variation, as well as transcriptional changes and post-translational modifications of proteins, they are the most proximal reporters of disease states or reversal of disease states.MethodsIn this study, we explore the potential effects of commonly available oral supplements (containing antioxidants, vitamins and omega-3 fatty acids) on the metabolomes of smokers (n = 11) compared to non-smokers (n = 17). At baseline and after 12 weeks of supplementation, metabolomic analysis was performed on serum by liquid and gas chromatography with mass spectroscopy (LC-MS and GC-MS). Furthermore, clinical parameters of skin aging, including cutometry as assessed by three dermatologist raters blinded to subjects' age and smoking status, were measured.ResultsLong-chain fatty acids, including palmitate and oleate, decreased in smokers by 0.76-fold (P = 0.0045) and 0.72-fold (P = 0.0112), respectively. These changes were not observed in non-smokers. Furthermore, age and smoking status showed increased glow (P = 0.004) and a decrease in fine wrinkling (P = 0.038). Cutometry showed an increase in skin elasticity in smokers (P = 0.049) but not in non-smokers. Complexion analysis software (VISIA) revealed decreases in the number of ultraviolet spots (P = 0.031), and cutometry showed increased elasticity (P = 0.05) in smokers but not non-smokers.ConclusionsAdditional future work may shed light on the specific mechanisms by which long-chain fatty acids can lead to increased glow, improved elasticity measures and decreased fine wrinkling in smokers' skin. Our study provides a novel, medicine-focused application of available metabolomic technology to identify changes in sera of human subjects with oxidative stress, and suggests that oral supplementation (in particular, commonly available antioxidants, vitamins and omega-3 fatty acids) affects these individuals in a way that is unique (compared to non-smokers) on a broad level
Imaging the cool gas, dust, star formation, and AGN in the first galaxies
When, and how, did the first galaxies and supermassive black holes (SMBH)
form, and how did they reionization the Universe? First galaxy formation and
cosmic reionization are among the last frontiers in studies of cosmic structure
formation. We delineate the detailed astrophysical probes of early galaxy and
SMBH formation afforded by observations at centimeter through submillimeter
wavelengths. These observations include studies of the molecular gas (= the
fuel for star formation in galaxies), atomic fine structure lines (= the
dominant ISM gas coolant), thermal dust continuum emission (= an ideal star
formation rate estimator), and radio continuum emission from star formation and
relativistic jets. High resolution spectroscopic imaging can be used to study
galaxy dynamics and star formation on sub-kpc scales. These cm and mm
observations are the necessary compliment to near-IR observations, which probe
the stars and ionized gas, and X-ray observations, which reveal the AGN.
Together, a suite of revolutionary observatories planned for the next decade
from centimeter to X-ray wavelengths will provide the requisite panchromatic
view of the complex processes involved in the formation of the first generation
of galaxies and SMBHs, and cosmic reionization.Comment: 8 pages total. White paper submitted to the Astro 2010 Decadal Surve
Genome-wide association study of receptive language ability of 12 year olds
Purpose: We have previously shown that individual differences in measures of receptive language ability at age 12 are highly heritable. The current study attempted to identify some of the genes responsible for the heritability of receptive language ability using a genome-wide association (GWA) approach.
Method: We administered four internet-based measures of receptive language (vocabulary, semantics, syntax, and pragmatics) to a sample of 2329 12-year-olds for whom DNA and genome-wide genotyping were available. Nearly 700,000 single-nucleotide polymorphisms (SNPs) and one million imputed SNPs were included in a GWA analysis of receptive language composite scores.
Results: No SNP associations met the demanding criterion of genome-wide significance that corrects for multiple testing across the genome (p < 5 ×10-8). The strongest SNP association did not replicate in an additional sample of 2639 12-year-olds.
Conclusion: These results indicate that individual differences in receptive language ability in the general population do not reflect common genetic variants that account for >3% of the phenotypic variance. The search for genetic variants associated with language skill will require larger samples and additional methods to identify and functionally characterize the full spectrum of risk variants
The Calibration of Monochromatic Far-Infrared Star Formation Rate Indicators
(Abridged) Spitzer data at 24, 70, and 160 micron and ground-based H-alpha
images are analyzed for a sample of 189 nearby star-forming and starburst
galaxies to investigate whether reliable star formation rate (SFR) indicators
can be defined using the monochromatic infrared dust emission centered at 70
and 160 micron. We compare recently published recipes for SFR measures using
combinations of the 24 micron and observed H-alpha luminosities with those
using 24 micron luminosity alone. From these comparisons, we derive a reference
SFR indicator for use in our analysis. Linear correlations between SFR and the
70 and 160 micron luminosity are found for L(70)>=1.4x10^{42} erg/s and
L(160)>=2x10^{42} erg/s, corresponding to SFR>=0.1-0.3 M_sun/yr. Below those
two luminosity limits, the relation between SFR and 70 micron (160 micron)
luminosity is non-linear and SFR calibrations become problematic. The
dispersion of the data around the mean trend increases for increasing
wavelength, becoming about 25% (factor ~2) larger at 70 (160) micron than at 24
micron. The increasing dispersion is likely an effect of the increasing
contribution to the infrared emission of dust heated by stellar populations not
associated with the current star formation. The non-linear relation between SFR
and the 70 and 160 micron emission at faint galaxy luminosities suggests that
the increasing transparency of the interstellar medium, decreasing effective
dust temperature, and decreasing filling factor of star forming regions across
the galaxy become important factors for decreasing luminosity. The SFR
calibrations are provided for galaxies with oxygen abundance 12+Log(O/H)>8.1.
At lower metallicity the infrared luminosity no longer reliably traces the SFR
because galaxies are less dusty and more transparent.Comment: 69 pages, 19 figures, 2 tables; accepted for publication on Ap
Herschel Far-Infrared and Sub-millimeter Photometry for the KINGFISH Sample of Nearby Galaxies
New far-infrared and sub-millimeter photometry from the Herschel Space
Observatory is presented for 61 nearby galaxies from the Key Insights on Nearby
Galaxies: A Far-Infrared Survey with Herschel (KINGFISH) sample. The
spatially-integrated fluxes are largely consistent with expectations based on
Spitzer far-infrared photometry and extrapolations to longer wavelengths using
popular dust emission models. Dwarf irregular galaxies are notable exceptions,
as already noted by other authors, as their 500um emission shows evidence for a
sub-millimeter excess. In addition, the fraction of dust heating attributed to
intense radiation fields associated with photo-dissociation regions is found to
be (21+/-4)% larger when Herschel data are included in the analysis. Dust
masses obtained from the dust emission models of Draine & Li are found to be on
average nearly a factor of two higher than those based on single-temperature
modified blackbodies, as single blackbody curves do not capture the full range
of dust temperatures inherent to any galaxy. The discrepancy is largest for
galaxies exhibiting the coolest far-infrared colors.Comment: Accepted for publication in Ap
Towards an embedding of Graph Transformation in Intuitionistic Linear Logic
Linear logics have been shown to be able to embed both rewriting-based
approaches and process calculi in a single, declarative framework. In this
paper we are exploring the embedding of double-pushout graph transformations
into quantified linear logic, leading to a Curry-Howard style isomorphism
between graphs and transformations on one hand, formulas and proof terms on the
other. With linear implication representing rules and reachability of graphs,
and the tensor modelling parallel composition of graphs and transformations, we
obtain a language able to encode graph transformation systems and their
computations as well as reason about their properties
Utilizing Three Years of Epidemiological Data from Medical Missions in Cambodia to Shape the Mobile Medical Clinic Formulary
Objective: The purpose of this project was to gather epidemiological data on common diseases and medications dispensed during medical mission teams to Cambodia to shape the mobile medical clinic formulary.
Methods: Data for patients seen during week-long, mobile, medical clinics was collected in Cambodia during Septembers 2012 to 2014. Patient’s gender, age, weight, blood pressure, glucose, pertinent laboratory values, diagnoses, and medications dispensed were collected. Blood pressure and glucose were measured in patients 18 years and above. Data collected onto paper intake forms were transferred onto spreadsheets without patient identifying information and analyzed for aggregate means, common diseases, and most dispensed medications. This project received institutional review board approval.
Results: A total of 1,015 patients were seen over three years. Women made up 61.4% and the mean age was 41.8 years. The most common diagnosis was gastrointestinal disorders (22.9%), which included gastroesophageal reflux disease and intestinal parasites. Next, 20.1% of patients had hypertension (BP\u3e140/90), 18.0% had presbyopia, 15.4% had back and joint pain, followed by 8.8% with headache, including migraines. Approximately 8.4% of patients had hyperglycemia (RPG \u3e140 mg/dl). Top five medications dispensed were acetaminophen, omeprazole, multivitamin, ibuprofen and metformin. For hypertension, amlodipine and lisinopril were dispensed.
Conclusion: Cambodia lacks systematic public health collection of epidemiological data for prevalence of diseases. Hence, investigators collected and analyzed information from week-long mobile medical clinics over three years. Proton-pump inhibitors and H. pylori lab tests are recommended for gastrointestinal disorders. Acetaminophen and ibuprofen are recommended for pain. Angiotensin-converting-enzyme inhibitors and dihydropyridine calcium channel blockers are recommended over diuretics since patients are already dehydrated. Metformin is recommended for diabetes. Vitamins and supplements are recommended for malnourished patients. Hemoglobin machine and urine test strips are suggested. This information should help future teams decide what medications and laboratory tests are most beneficial on medical teams in Cambodia
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