356 research outputs found
HIV/Hepatitis Prevention in Drug Abuse Treatment Programs: Guidance From Research
A large body of research examines the relationship between HIV and drug dependence, but considerably less information is available on viral hepatitis and drug dependence. This article summarizes research indicating what drug abuse treatment programs can do to prevent their patients from acquiring HIV or hepatitis infection and to limit the consequences for patients who are already infected. Drug treatment programs can play a pivotal role in preventing, detecting, and treating HIV and hepatitis. Some activities can be accomplished by providers’ simply becoming aware of the issues; others will require significant infusion of leadership, education, and fiscal support
A novel method for measuring the extragalactic background light: Fermi application to the lobes of Fornax A
We describe a new method for measuring the extragalactic background light
(EBL) through the detection of -ray inverse Compton (IC) emission due
to scattering of the EBL photons off relativistic electrons in the lobes of
radio galaxies. Our method has no free physical parameters and is a powerful
tool when the lobes are characterized by a high energy sharp break or cutoff in
their electron energy distribution (EED). We show that such a feature will
produce a high energy IC `imprint' of the EBL spectrum in which the radio lobes
are embedded, and show how this imprint can be used to derive the EBL. We apply
our method to the bright nearby radio galaxy Fornax A, for which we
demonstrate, using WMAP and EGRET observations, that the EED of its lobes is
characterized by a conveniently located cutoff, bringing the IC EBL emission
into the {\sl Fermi} energy range. We show that {\sl Fermi} will set upper
limits to the optical EBL and measure the more elusive infrared EBL.Comment: ApJL, accepte
The kinesin Eg5 drives poleward microtubule flux in Xenopus laevis egg extract spindles
Although mitotic and meiotic spindles maintain a steady-state length during metaphase, their antiparallel microtubules slide toward spindle poles at a constant rate. This “poleward flux” of microtubules occurs in many organisms and may provide part of the force for chromosome segregation. We use quantitative image analysis to examine the role of the kinesin Eg5 in poleward flux in metaphase Xenopus laevis egg extract spindles. Pharmacological inhibition of Eg5 results in a dose–responsive slowing of flux, and biochemical depletion of Eg5 significantly decreases the flux rate. Our results suggest that ensembles of nonprocessive Eg5 motors drive flux in metaphase Xenopus extract spindles
The Jet and Circumnuclear Environment of 3C 293
We present the new HST near-infrared polarimetry, broad and narrow-band
imaging, and MERLIN 4.5GHz Multi-Frequency Synthesis radio imaging of 3C 293, a
unique radio galaxy whose host is an obvious merger remnant, in an
exceptionally under-dense region of space. We have discovered near-infrared,
optical, and ultra-violet synchrotron emission from the jet. In the optical,
the jet is mostly obscured by a dust lane, but three knots are clear in our HST
NICMOS images at 1.6 and 2.0 microns, clearly aligning with features in the
radio. The outer jet knot is highly polarized (~15%) at 2 microns, confirming
the synchrotron emission mechanism. The radio-IR spectral index steepens
significantly with distance from the nucleus, as in 3C 273 and in contrast to M
87. The inner knot is visible (with hindsight) on the WFPC2 and STIS images
obtained for the earlier 3CR HST snapshot surveys. There is no [Fe II] emission
seen associated with the jet, constraining the role of shock-induced ionisation
by the jet. Overall there is a strong implication that the NIR jet emission is
indeed synchrotron.
From our NIR images, the core of the galaxy is clearly identifiable with the
main feature in the western extension of the radio ``jet'' image, although no
unresolved AGN component is identifiable even at K-band, consistent with an
FRII-like nucleus obscured by an optically thick torus. The galaxy appears to
have a single nucleus, with any multiple nuclei falling within the central
</~100 pc.Comment: ApJ accepted. 31 pages, 12 figures reproduced here at low resolution.
High resolution version available from
http://www.stsci.edu/~floyd/BIBLIOTECA/3c293
Will "Combined Prevention" Eliminate Racial/Ethnic Disparities in HIV Infection among Persons Who Inject Drugs in New York City?
It has not been determined whether implementation of combined prevention programming for persons who inject drugs reduce racial/ethnic disparities in HIV infection. We examine racial/ethnic disparities in New York City among persons who inject drugs after implementation of the New York City Condom Social Marketing Program in 2007. Quantitative interviews and HIV testing were conducted among persons who inject drugs entering Mount Sinai Beth Israel drug treatment (2007–2014). 703 persons who inject drugs who began injecting after implementation of large-scale syringe exchange were included in the analyses. Factors independently associated with being HIV seropositive were identified and a published model was used to estimate HIV infections due to sexual transmission. Overall HIV prevalence was 4%; Whites 1%, African-Americans 17%, and Hispanics 4%. Adjusted odds ratios were 21.0 (95% CI 5.7, 77.5) for African-Americans to Whites and 4.5 (95% CI 1.3, 16.3) for Hispanics to Whites. There was an overall significant trend towards reduced HIV prevalence over time (adjusted odd ratio = 0.7 per year, 95% confidence interval (0.6–0.8). An estimated 75% or more of the HIV infections were due to sexual transmission. Racial/ethnic disparities among persons who inject drugs were not significantly different from previous disparities. Reducing these persistent disparities may require new interventions (treatment as prevention, pre-exposure prophylaxis) for all racial/ethnic groups
O/IR Polarimetry for the 2010 Decade (GAN): Science at the Edge, Sharp Tools for All
Science opportunities and recommendations concerning optical/infrared
polarimetry for the upcoming decade in the field of Galactic science.
Community-based White Paper to Astro2010 in response to the call for such
papers.Comment: White Paper to the Galactic Neighborhood (GAN) Science Frontiers
Panel of the Astro2010 Decadal Surve
HST/ACS Emission Line Imaging of Low Redshift 3CR Radio Galaxies I: The Data
We present 19 nearby (z<0.3) 3CR radio galaxies imaged at low- and
high-excitation as part of a Cycle 15 Hubble Space Telescope snapshot survey
with the Advanced Camera for Surveys. These images consist of exposures of the
H-alpha (6563 \AA, plus [NII] contamination) and [OIII] 5007 \AA emission lines
using narrow-band linear ramp filters adjusted according to the redshift of the
target. To facilitate continuum subtraction, a single-pointing 60 s line-free
exposure was taken with a medium-band filter appropriate for the target's
redshift. We discuss the steps taken to reduce these images independently of
the automated recalibration pipeline so as to use more recent ACS flat-field
data as well as to better reject cosmic rays. We describe the method used to
produce continuum-free (pure line-emission) images, and present these images
along with qualitative descriptions of the narrow-line region morphologies we
observe. We present H-alpha+[NII] and [OIII] line fluxes from aperture
photometry, finding the values to fall expectedly on the redshift-luminosity
trend from a past HST/WFPC2 emission line study of a larger, generally higher
redshift subset of the 3CR. We also find expected trends between emission line
luminosity and total radio power, as well as a positive correlation between the
size of the emission line region and redshift. We discuss the associated
interpretation of these results, and conclude with a summary of future work
enabled by this dataset.Comment: 18 pages, 12 figures, accepted for publication in ApJ
Using the Multiphase Optimization Strategy (MOST) to optimize an HIV care continuum intervention for vulnerable populations : a study protocol
Abstract: Background. More than half of persons living with HIV (PLWH) in the United States are insufficiently engaged in HIV primary care and not taking antiretroviral therapy (ART), mainly African Americans/Blacks and Hispanics. In the proposed project, a potent and innovative research methodology, the multiphase optimization strategy (MOST), will be employed to develop a highly efficacious, efficient, scalable, and cost-effective intervention to increase engagement along the HIV care continuum. Whereas randomized controlled trials are valuable for evaluating the efficacy of multi-component interventions as a package, they are not designed to evaluate which specific components contribute to efficacy. MOST, a pioneering, engineering-inspired framework, addresses this problem through highly efficient randomized experimentation to assess the performance of individual intervention components and their interactions. We propose to use MOST to engineer an intervention to increase engagement along the HIV care continuum for African American/Black and Hispanic PLWH not well engaged in care and not taking ART. Further, the intervention will be optimized for cost-effectiveness. A similar set of multi-level factors impede both HIV care and ART initiation for African American/Black and Hispanic PLWH, primary among them individual- (e.g., substance use, distrust, fear), social- (e.g., stigma), and structural-level barriers (e.g., difficulties accessing ancillary services). Guided by a multi-level social cognitive theory, the study will evaluate five distinct intervention components (i.e., Motivational Interviewing counseling sessions, pre-adherence preparation, support groups, peer mentorship, and patient navigation), each designed to address a specific barrier to HIV care and ART initiation. These components are well-grounded in the empirical literature and were found acceptable, feasible, and promising with respect to efficacy in a preliminary study. Methods/design. Study aims are: 1) using a highly efficient fractional factorial experimental design, identify which of five intervention components contribute meaningfully to improvement in HIV viral suppression, and secondary outcomes of ART adherence and engagement in HIV primary care; 2) identify mediators and moderators of intervention component efficacy; and 3) using a mathematical modeling approach, build the most cost-effective and efficient intervention package from the efficacious components. A heterogeneous sample of African American/Black and Hispanic PLWH (with respect to age, substance use, and sexual minority status) will be recruited with a proven hybrid sampling method using targeted sampling in community settings and peer recruitment (N=512). Discussion. This is the first study to apply the MOST framework in the field of HIV prevention and treatment. This innovative study will produce an HIV care continuum intervention for the nation's most vulnerable PLWH, optimized for cost-effectiveness, and with exceptional levels of efficacy, efficiency, and scalability
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