1,983 research outputs found
Understanding Primary Care Physician Perspectives On the Diagnosis and Management of Non-Alcoholic Fatty Liver Disease: a Qualitative Study
Primary care physicians (PCPs) are well suited to manage patients with non-alcoholic fatty liver disease (NAFLD), but the limited, existing research suggests inadequate knowledge about the natural history, diagnostic methods, and management of NAFLD. The purpose of this qualitative study is to further understand the knowledge and practices for the diagnosis and management of NAFLD among PCPs. We conducted in-depth interviews with PCPs in the Greater Houston area, addressing current clinical practices used for diagnosing and managing NAFLD, as well as the perceptions of the PCPs regarding the burden of NAFLD on patients. We recorded interviews, transcribed them, coded transcripts, and identified patterns and themes. The interviewed PCPs (n = 16) were from internal or family medicine, with a range of experience (1.5-30 years). We found variations in NAFLD diagnosis and management across practices and by insurance status. Patients with abnormal liver imaging who had insurance or were within a safety-net healthcare system were referred by PCPs to specialists. Uninsured patients with persistently elevated liver enzymes received lifestyle recommendations from PCPs without confirmatory imaging or specialist referral. The role of PCPs in NAFLD management varied, with some helping patients set dietary and physical activity goals while others provided only general recommendations and/or referred patients to a dietitian. The diagnosis and management of NAFLD vary widely among PCPs and may be impacted by patients\u27 insurance status and clinic-specific practices. The increasing burden of NAFLD in the U.S. medical system highlights the need for more PCPs involvement in managing NAFLD
Analyzing aviation safety: problems, challenges, opportunities
a b s t r a c t This paper reviews the economic literature relating to aviation safety; analyzes the safety record of commercial passenger aviation in the United States and abroad; examines aviation security as a growing dimension of aviation safety; and identifies emerging issues in airline safety and challenges for aviation safety research. Commercial airline safety has improved dramatically since the industry's birth over a century ago. Fatal accident rates for large scheduled jet airlines have fallen to the level where (along many dimensions) aviation is now the safest mode of commercial transportation. However, safety performance has not been evenly distributed across all segments of commercial aviation, nor among all countries and regions of the world. The finding that developing countries have much poorer safety records has been a persistent conclusion in aviation safety research and continues to be the case. Unfortunately, operations data are not available for many of the airlines that experience fatal accidents, so it is not possible to calculate reliable fatality rates for many segments of the worldwide aviation industry. Without more complete information, it will likely be difficult to make substantial improvements in the safety of these operations. Challenges to improving aviation security include: how much to focus on identifying the terrorists as opposed to identifying the tools they might use; determining how to respond to terrorist threats; and determining the public versus private roles in providing aviation security. The next generation of safety challenges now require development and understanding of new forms of data to improve safety in other segments of commercial aviation, and moving from a reactive, incident-based approach toward a more proactive, predictive and systems-based approach
The Star-Forming Galaxy Contribution to the Cosmic MeV and GeV Gamma-Ray Background
While star-forming galaxies could be major contributors to the cosmic GeV
-ray background, they are expected to be MeV-dim because of the "pion
bump" falling off below ~100 MeV. However, there are very few observations of
galaxies in the MeV range, and other emission processes could be present. We
investigate the MeV background from star-forming galaxies by running one-zone
models of cosmic ray populations, including Inverse Compton and bremsstrahlung,
as well as nuclear lines (including Al), emission from core-collapse
supernovae, and positron annihilation emission, in addition to the pionic
emission. We use the Milky Way and M82 as templates of normal and starburst
galaxies, and compare our models to radio and GeV--TeV -ray data. We
find that (1) higher gas densities in high-z normal galaxies lead to a strong
pion bump, (2) starbursts may have significant MeV emission if their magnetic
field strengths are low, and (3) cascades can contribute to the MeV emission of
starbursts if they emit mainly hadronic -rays. Our fiducial model
predicts that most of the unresolved GeV background is from star-forming
galaxies, but this prediction is uncertain by an order of magnitude. About ~2%
of the claimed 1 MeV background is diffuse emission from star-forming galaxies;
we place a firm upper limit of <~10% based on the spectral shape of the
background. The star-formation contribution is constrained to be small, because
its spectrum is peaked, while the observed background is steeply falling with
energy through the MeV-GeV range.Comment: Published in ApJ, 27 pages, emulateapj format. Readers may be
interested in the concurrent paper by Chakraborty and Fields
(arXiv:1206.0770), a calculation of the Inverse Compton background from
star-forming galaxie
Obscurin modulates the assembly and organization of sarcomeres and the sarcoplasmic reticulum
Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/154636/1/fsb2fj065761com.pd
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Declines in cigarette smoking among US adolescents and young adults: indications of independence from e-cigarette vaping surge
ObjectiveTo compare trends in cigarette smoking and nicotine vaping among US population aged 17-18 years and 18-24 years.MethodsRegression analyses identified trends in ever and current use of cigarettes and e-cigarettes, using three US representative surveys from 1992 to 2022.ResultsFrom 1997 to 2020, cigarette smoking prevalence among those aged 18-24 years decreased from 29.1% (95% CI 27.4% to 30.7%) to 5.4% (95% CI 3.9% to 6.9%). The decline was highly correlated with a decline in past 30-day smoking among those aged 17-18 years (1997: 36.8% (95% CI 35.6% to 37.9%; 2022: 3.0% (95% CI 1.8% to 4.1%). From 2017 to 2019, both ever-vaping and past 30-day nicotine vaping (11.0% to 25.5%) surged among those 17-18 years, however there was no increase among those aged 18-24 years. Regression models demonstrated that the surge in vaping was independent of the decline in cigarette smoking. In the 24 most populous US states, exclusive vaping did increase among those aged 18-24 years, from 1.7% to 4.0% to equivalent to 40% of the decline in cigarette smoking between 2014-15 and 2018-19. Across these US states, the correlation between the changes in vaping and smoking prevalence was low (r=0.11). In the two US states with >US$1/fluid mL tax on e-cigarettes in 2017, cigarette smoking declined faster than the US average.ConclusionsSince 1997, a large decline in cigarette smoking occurred in the US population under age 24 years, that was independent of the 2017-19 adolescent surge in past 30-day e-cigarette vaping. Further research is needed to assess whether the 2014-15 to 2018-19 increase in exclusive vaping in those aged 18-24 years is a cohort effect from earlier dependence on e-cigarette vaping as adolescents
Galactic-Centre Gamma Rays in CMSSM Dark Matter Scenarios
We study the production of gamma rays via LSP annihilations in the core of
the Galaxy as a possible experimental signature of the constrained minimal
supersymmetric extension of the Standard Model (CMSSM), in which
supersymmetry-breaking parameters are assumed to be universal at the GUT scale,
assuming also that the LSP is the lightest neutralino chi. The part of the
CMSSM parameter space that is compatible with the measured astrophysical
density of cold dark matter is known to include a stau_1 - chi coannihilation
strip, a focus-point strip where chi has an enhanced Higgsino component, and a
funnel at large tanb where the annihilation rate is enhanced by the poles of
nearby heavy MSSM Higgs bosons, A/H. We calculate the total annihilation rates,
the fractions of annihilations into different Standard Model final states and
the resulting fluxes of gamma rays for CMSSM scenarios along these strips. We
observe that typical annihilation rates are much smaller in the coannihilation
strip for tanb = 10 than along the focus-point strip or for tanb = 55, and that
the annihilation branching ratios differ greatly between the different dark
matter strips. Whereas the current Fermi-LAT data are not sensitive to any of
the CMSSM scenarios studied, and the calculated gamma-ray fluxes are probably
unobservably low along the coannihilation strip for tanb = 10, we find that
substantial portions of the focus-point strips and rapid-annihilation funnel
regions could be pressured by several more years of Fermi-LAT data, if
understanding of the astrophysical background and/or systematic uncertainties
can be improved in parallel.Comment: 33 pages, 12 figures, comments and references added, version to
appear in JCA
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Cigarette smoking decline among US young adults from 2000 to 2019, in relation to state-level cigarette price and tobacco control expenditure
ObjectiveTo investigate the association of state-level cigarette price and tobacco control expenditure with the large 2000-2019 decline in cigarette smoking among US 18-24 year-olds.MethodsSmoking behaviour was assessed in the 24 most populous US states using the 1992-2019 Tobacco Use Supplements to the Current Population Survey; association with price and expenditure was tested using adjusted logistic regression. States were ranked by inflation-adjusted average price and tobacco control expenditure and grouped into tertiles. State-specific time trends were estimated, with slope changes in 2001/2002 and 2010/2011.ResultsBetween 2000 and 2010, the odds of smoking among US young adults decreased by a third (adjusted OR, AOR 0.68, 95% CI 0.56 to 0.84). By 2019, these odds were one-quarter of their 2000 level (AOR 0.24, 95% CI 0.19 to 0.31). Among states in the lowest tertile of price/expenditure tobacco control activity, initially higher young adult smoking decreased by 13 percentage points from 2010 to 2018-2019, to a prevalence of 5.6% (95% CI 4.5% to 6.8%), equal to that in the highest tobacco-control tertile of states (6.5%, 95% CI 5.2% to 7.8%). Neither state tobacco control spending (AOR 1.0, 95% CI 0.999 to 1.002) nor cigarette price (AOR 0.96, 95% CI: 0.92 to 1.01) were associated with young adult smoking in statistical models. In 2019, seven states had prevalence over 3 SDs higher than the 24-state mean.ConclusionNational programmes may have filled a gap in state-level interventions, helping drive down the social acceptability of cigarette smoking among young adults across all states. Additional interventions are needed to assist high-prevalence states to further reduce smoking
Evolutionary Status of Dwarf ``Transition'' Galaxies
We present deep B, R and Halpha imaging of 3 dwarf galaxies: NGC3377A,
NGC4286, and IC3475. Based on previous broadband imaging and HI studies, these
mixed-morphology galaxies were proposed by Sandage & Hoffman (1991) to be,
respectively, a gas-rich low surface brightness Im dwarf, a nucleated dwarf
that has lost most of its gas and is in transition from Im to dS0,N, and the
prototypical example of a gas-poor ``huge low surface brightness'' early-type
galaxy. From the combination of our broadband and Halpha imaging with the
published information on the neutral gas content of these three galaxies, we
find that (1) NGC3377A is a dwarf spiral; (2) NGC3377A and NGC4286 have
comparable amounts of ongoing star formation, as indicated by their Halpha
emission, while IC3475 has no detected HII regions to a very low limit; (3) the
global star formation rates are at least a factor of 20 below that of 30
Doradus for NGC3377A and NGC4286; (4) while the amount of star formation is
comparable, the distribution of star forming regions is very different between
NGC3377A and NGC4286; (5) given their current star formation rates and gas
contents, both NGC3377A and NGC4286 can continue to form stars for more than a
Hubble time; (6) both NGC3377A and NGC4286 have integrated total B-R colors
that are redder than the integrated total B-R color for IC3475, and thus it is
unlikely that either galaxy will ever evolve into an IC3475 counterpart; and
(7) IC3475 is too blue to be a dE. We thus conclude that we have not identified
potential precursors to galaxies such as IC3475, and unless signifcant changes
occur in the star formation rates, neither NGC3377A nor NGC4286 will evolve
into a dwarf elliptical or dwarf spheroidal within a Hubble time.Comment: 34 pages, 6 jpg figures, 3 postscript figures, and 4 tables, uses
AASTeX, ApJ, in pres
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