507 research outputs found
Multi-color Optical and NIR Light Curves of 64 Stripped-Envelope Core-Collapse Supernovae
We present a densely-sampled, homogeneous set of light curves of 64 low
redshift (z < 0.05) stripped-envelope supernovae (SN of type IIb, Ib, Ic and
Ic-bl). These data were obtained between 2001 and 2009 at the Fred L. Whipple
Observatory (FLWO) on Mt. Hopkins in Arizona, with the optical FLWO 1.2-m and
the near-infrared PAIRITEL 1.3-m telescopes. Our dataset consists of 4543
optical photometric measurements on 61 SN, including a combination of UBVRI,
UBVr'i', and u'BVr'i', and 2142 JHKs near-infrared measurements on 25 SN. This
sample constitutes the most extensive multi-color data set of stripped-envelope
SN to date. Our photometry is based on template-subtracted images to eliminate
any potential host galaxy light contamination. This work presents these
photometric data, compares them with data in the literature, and estimates
basic statistical quantities: date of maximum, color, and photometric
properties. We identify promising color trends that may permit the
identification of stripped-envelope SN subtypes from their photometry alone.
Many of these SN were observed spectroscopically by the CfA SN group, and the
spectra are presented in a companion paper (Modjaz et al. 2014). A thorough
exploration that combines the CfA photometry and spectroscopy of
stripped-envelope core-collapse SN will be presented in a follow-up paper.Comment: 26 pages, 17 figures, 8 tables. Revised version resubmitted to ApJ
Supplements after referee report. Additional online material is available
through http://cosmo.nyu.edu/SNYU
Intended and Unintended Effects of E-cigarette Taxes on Youth Tobacco Use
Over the past decade, rising youth use of e-cigarettes and other electronic nicotine delivery systems (ENDS) has prompted aggressive regulation by state and local governments. Between 2010 and 2019, ten states and two large counties adopted ENDS taxes. Applying a continuous treatment difference-in-differences approach to data from two large national datasets (Monitoring the Future and the Youth Risk Behavior Surveillance System), this study explores the impact of ENDS taxes on youth tobacco use. We find that ENDS taxes reduce youth e-cigarette consumption, with estimated e-cigarette tax elasticities of -0.06 to -0.21. However, we estimate sizable positive cigarette cross-tax elasticities, suggesting economic substitution between cigarettes and e-cigarettes for youth. These substitution effects are particularly large for frequent cigarette smoking. We conclude that the unintended effects of ENDS taxation may more than fully offset any public health gains
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Trends in the Population Prevalence of People Who Inject Drugs in US Metropolitan Areas 1992–2007
Background:
People who inject drugs (PWID) have increased risk of morbidity and mortality. We update and present estimates and trends of the prevalence of current PWID and PWID subpopulations in 96 US metropolitan statistical areas (MSAs) for 1992–2007. Current estimates of PWID and PWID subpopulations will help target services and help to understand long-term health trends among PWID populations.
Methodology:
We calculated the number of PWID in the US annually from 1992–2007 and apportioned estimates to MSAs using multiplier methods. We used four types of data indicating drug injection to allocate national annual totals to MSAs, creating four distinct series of component estimates of PWID in each MSA and year. The four component estimates are averaged to create the best estimate of PWID for each MSA and year. We estimated PWID prevalence rates for three subpopulations defined by gender, age, and race/ethnicity. We evaluated trends using multi-level polynomial models.
Results:
PWID per 10,000 persons aged 15–64 years varied across MSAs from 31 to 345 in 1992 (median 104.4) to 34 to 324 in 2007 (median 91.5). Trend analysis indicates that this rate declined during the early period and then was relatively stable in 2002–2007. Overall prevalence rates for non-Hispanic black PWID increased in 2005 as compared to other racial/ethnic groups. Hispanic prevalence, in contrast, declined across time. Importantly, results show a worrisome trend in young PWID prevalence since HAART was initiated – the mean prevalence was 90 to 100 per 10,000 youth in 1992–1996, but increased to >120 PWID per 10,000 youth in 2006–2007.
Conclusions:
Overall, PWID rates remained constant since 2002, but increased for two subpopulations: non-Hispanic black PWID and young PWID. Estimates of PWID are important for planning and evaluating public health programs to reduce harm among PWID and for understanding related trends in social and health outcomes
The GALEX Ultraviolet Atlas of Nearby Galaxies
We present images, integrated photometry, and surface-brightness and color profiles for a total of 1034 nearby galaxies recently observed by the Galaxy Evolution Explorer (GALEX) satellite in its far-ultraviolet (FUV; λ_(eff) = 1516 Å) and near-ultraviolet (NUV; λ_(eff) = 2267 Å) bands. Our catalog of objects is derived primarily from the GALEX Nearby Galaxies Survey (NGS) supplemented by galaxies larger than 1' in diameter serendipitously found in these fields and in other GALEX exposures of similar of greater depth. The sample analyzed here adequately describes the distribution and full range of properties (luminosity, color, star formation rate [SFR]) of galaxies in the local universe. From the surface brightness profiles obtained we have computed asymptotic magnitudes, colors, and luminosities, along with the concentration indices C31 and C42. We have also morphologically classified the UV surface brightness profiles according to their shape. This data set has been complemented with archival optical, near-infrared, and far-infrared fluxes and colors. We find that the integrated (FUV − K) color provides robust discrimination between elliptical and spiral/irregular galaxies and also among spiral galaxies of different subtypes. Elliptical galaxies with brighter K-band luminosities (i.e., more massive) are redder in (NUV − K) color but bluer in (FUV − NUV) (a color sensitive to the presence of a strong UV upturn) than less massive ellipticals. In the case of the spiral/irregular galaxies our analysis shows the presence of a relatively tight correlation between the (FUV − NUV) color (or, equivalently, the slope of the UV spectrum, β) and the total infrared-to-UV ratio. The correlation found between (FUV − NUV) color and K-band luminosity (with lower luminosity objects being bluer than more luminous ones) can be explained as due to an increase in the dust content with galaxy luminosity. The images in this Atlas along with the profiles and integrated properties are publicly available through a dedicated Web page
Metropolitan Social Environments and Pre-HAART/HAART Era Changes in Mortality Rates (per 10,000 Adult Residents) among Injection Drug Users Living with AIDS
Background
Among the largest US metropolitan areas, trends in mortality rates for injection drug users (IDUs) with AIDS vary substantially. Ecosocial, risk environment and dialectical theories suggest many metropolitan areas characteristics that might drive this variation. We assess metropolitan area characteristics associated with decline in mortality rates among IDUs living with AIDS (per 10,000 adult MSA residents) after highly active antiretroviral therapy (HAART) was developed.
Methods
This is an ecological cohort study of 86 large US metropolitan areas from 1993–2006. The proportional rate of decline in mortality among IDUs diagnosed with AIDS (as a proportion of adult residents) from 1993–1995 to 2004–2006 was the outcome of interest. This rate of decline was modeled as a function of MSA-level variables suggested by ecosocial, risk environment and dialectical theories. In multiple regression analyses, we used 1993–1995 mortality rates to (partially) control for pre-HAART epidemic history and study how other independent variables affected the outcomes.
Results
In multivariable models, pre-HAART to HAART era increases in ‘hard drug’ arrest rates and higher pre-HAART income inequality were associated with lower relative declines in mortality rates. Pre-HAART per capita health expenditure and drug abuse treatment rates, and pre- to HAART-era increases in HIV counseling and testing rates, were weakly associated with greater decline in AIDS mortality.
Conclusions
Mortality among IDUs living with AIDS might be decreased by reducing metropolitan income inequality, increasing public health expenditures, and perhaps increasing drug abuse treatment and HIV testing services. Given prior evidence that drug-related arrest rates are associated with higher HIV prevalence rates among IDUs and do not seem to decrease IDU population prevalence, changes in laws and policing practices to reduce such arrests while still protecting public order should be considered
Recent star formation in nearby galaxies from GALEX imaging:M101 and M51
The GALEX (Galaxy Evolution Explorer) Nearby Galaxies Survey is providing
deep far-UV and near-UV imaging for a representative sample of galaxies in the
local universe. We present early results for M51 and M101, from GALEX UV
imaging and SDSS optical data in five bands. The multi-band photometry of
compact stellar complexes in M101 is compared to population synthesis models,
to derive ages, reddening, reddening-corrected luminosities and current/initial
masses. The GALEX UV photometry provides a complete census of young compact
complexes on a approximately 160pc scale. A galactocentric gradient of the
far-UV - near-UV color indicates younger stellar populations towards the outer
parts of the galaxy disks, the effect being more pronounced in M101 than in
M51.Comment: This paper will be published as part of the Galaxy Evolution Explorer
(GALEX) Astrophysical Journal Letters Special Issue. Full paper available
from http://dolomiti.pha.jhu.edu . Links to full set of papers will be
available at http://www.galex.caltech.edu/PUBLICATIONS/ after November 22,
200
Continuous NPWT regulates fibrosis in murine diabetic wound healing
Scarring is associated with significant morbidity. The mechanical signaling factor yes-associated protein (YAP) has been linked to Engrailed-1 (En1)-lineage positive fibroblasts (EPFs), a pro-scarring fibroblast lineage, establishing a connection between mechanotransduction and fibrosis. In this study, we investigate the impact of micromechanical forces exerted through negative pressure wound therapy (NPWT) on the pathophysiology of fibrosis. Full-thickness excisional dorsal skin wounds were created on diabetic (db/db) mice which were treated with occlusive covering (control) or NPWT (continuous, -125 mmHg, 7 days; NPWT). Analysis was performed on tissue harvested 10 days after wounding. NPWT was associated with increased YAP
Chemical and Photometric Evolution of Extended Ultraviolet Disks: Optical Spectroscopy of M83 (NGC5236) and NGC4625
We present the results from the analysis of optical spectra of 31
Halpha-selected regions in the extended UV (XUV) disks of M83 (NGC5236) and
NGC4625 recently discovered by GALEX. The spectra were obtained using IMACS at
Las Campanas Observatory 6.5m Magellan I telescope and COSMIC at the Palomar
200-inch telescope, respectively for M83 and NGC4625. The line ratios measured
indicate nebular oxygen abundances (derived from the R23 parameter) of the
order of Zsun/5-Zsun/10. For most emission-line regions analyzed the line
fluxes and ratios measured are best reproduced by models of photoionization by
single stars with masses in the range 20-40 Msun and oxygen abundances
comparable to those derived from the R23 parameter. We find indications for a
relatively high N/O abundance ratio in the XUV disk of M83. Although the
metallicities derived imply that these are not the first stars formed in the
XUV disks, such a level of enrichment could be reached in young spiral disks
only 1 Gyr after these first stars would have formed. The amount of gas in the
XUV disks allow maintaining the current level of star formation for at least a
few Gyr.Comment: 52 pages, 8 tables, 7 figures, accepted for publication in Ap
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Predictors of historical change in drug treatment coverage among people who inject drugs in 90 large metropolitan areas in the USA, 1993–2007
Background
Adequate access to effective treatment and medication assisted therapies for opioid dependence has led to improved antiretroviral therapy adherence and decreases in morbidity among people who inject drugs (PWID), and can also address a broad range of social and public health problems. However, even with the success of syringe service programs and opioid substitution programs in European countries (and others) the US remains historically low in terms of coverage and access with regard to these programs. This manuscript investigates predictors of historical change in drug treatment coverage for PWID in 90 US metropolitan statistical areas (MSAs) during 1993–2007, a period in which, overall coverage did not change.
Methods
Drug treatment coverage was measured as the number of PWID in drug treatment, as calculated by treatment entry and census data, divided by numbers of PWID in each MSA. Variables suggested by the Theory of Community Action (i.e., need, resource availability, institutional opposition, organized support, and service symbiosis) were analyzed using mixed-effects multivariate models within dependent variables lagged in time to study predictors of later change in coverage.
Results
Mean coverage was low in 1993 (6.7%; SD 3.7), and did not increase by 2007 (6.4%; SD 4.5). Multivariate results indicate that increases in baseline unemployment rate (β = 0.312; pseudo-p < 0.0002) predict significantly higher treatment coverage; baseline poverty rate (β = − 0.486; pseudo-p < 0.0001), and baseline size of public health and social work workforce (β = 0.425; pseudo-p < 0.0001) were predictors of later mean coverage levels, and baseline HIV prevalence among PWID predicted variation in treatment coverage trajectories over time (baseline HIV * Time: β = 0.039; pseudo-p < 0.001). Finally, increases in black/white poverty disparity from baseline predicted significantly higher treatment coverage in MSAs (β = 1.269; pseudo-p < 0.0001).
Conclusions
While harm reduction programs have historically been contested and difficult to implement in many US communities, and despite efforts to increase treatment coverage for PWID, coverage has not increased. Contrary to our hypothesis, epidemiologic need, seems not to be associated with change in treatment coverage over time. Resource availability and institutional opposition are important predictors of change over time in coverage. These findings suggest that new ways have to be found to increase drug treatment coverage in spite of economic changes and belt-tightening policy changes that will make this difficult
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