3,654 research outputs found
A Morphological and Multicolor Survey for Faint QSOs in the Groth-Westphal Strip
Quasars representative of the populous faint end of the luminosity function
are frustratingly dim with m~24 at intermediate redshift; moreover groundbased
surveys for such faint QSOs suffer substantial morphological contamination by
compact galaxies having similar colors. In order to establish a more reliable
ultrafaint QSO sample, we used the APO 3.5-m telescope to take deep groundbased
U-band CCD images in fields previously imaged in V,I with WFPC2/HST. Our
approach hence combines multicolor photometry with the 0.1" spatial resolution
of HST, to establish a morphological and multicolor survey for QSOs extending
about 2 magnitudes fainter than most extant groundbased surveys. We present
results for the "Groth-Westphal Strip", in which we identify 10 high likelihood
UV-excess candidates having stellar or stellar-nucleus+galaxy morphology in
WFPC2. For m(606)<24.0 (roughly B<24.5) the surface density of such QSO
candidates is 420 (+180,-130) per square degree, or a surface density of 290
(+160,-110) per square degree with an additional V-I cut that may further
exclude compact emission line galaxies. Even pending confirming spectroscopy,
the observed surface density of QSO candidates is already low enough to yield
interesting comparisons: our measures agree extremely well with the predictions
of several recent luminosity function models.Comment: 29 pages including 6 tables and 7 figures. As accepted for
publication in The Astronomical Journal (minor revisions
Access to substance use treatment among young adults who use prescription opioids non-medically
BACKGROUND: Non-medical prescription opioid (NMPO) use is a substantial public health problem in the United States, with 1.5 million new initiates annually. Only 746,000 people received treatment for NMPO use in 2013, demonstrating substantial disparities in access to treatment. This study aimed to assess correlates of accessing substance use treatment among young adult NMPO users in Rhode Island, a state heavily impacted by NMPO use and opioid overdose.
METHODS: This analysis uses data from a study of 200 Rhode Island residents aged 18 to 29 who reported NMPO use in the past 30 days. We compared individuals who had ever successfully enrolled in a substance use treatment program without ever facing barriers, individuals who had ever attempted to enroll but were unable, and individuals who never attempted to enroll. We used multinomial logistic regression to determine the independent correlates of never attempting and unsuccessfully attempting to access substance use treatment.
RESULTS: Among 200 participants, the mean age was 24.5, 65.5% were male, and 61.5% were white. Nearly half (45.5%) had never attempted to enroll in substance use treatment, while 35.0% had successfully enrolled without ever facing barriers and 19.5% were unsuccessful in at least one attempt to enroll. In multivariable models, non-white participants were more likely to never have attempted to enroll compared to white participants. Previous incarceration, experiencing drug-related discrimination by the medical community, and a monthly income of 1500 were associated with a decreased likelihood of never attempting to enroll. A history of overdose and a monthly income of 1500 were associated with an increased likelihood of unsuccessfully accessing treatment. The most commonly reported barriers to accessing treatment were waiting lists (n = 23), health insurance not approving enrollment (n = 20), and inability to pay (n = 16).
CONCLUSIONS: This study demonstrates significant disparities in access to treatment among young adults who report NMPO use. A history of overdose was shown to correlate with experiencing barriers to substance use treatment utilization. Interventions are needed to reduce drug-related discrimination in clinical settings and to provide mechanisms that link young adults (particularly with a history of overdose) to evidence-based treatment
Cellular Models of Aggregation-Dependent Template-Directed Proteolysis to Characterize Tau Aggregation Inhibitors for Treatment of Alzheimer's Disease
Copyright © 2015, The American Society for Biochemistry and Molecular Biology. Acknowledgements-We thank Drs Timo Rager and Rolf Hilfiker (Solvias, Switzerland) for polymorph analyses.Peer reviewedPublisher PD
Atmospheric phase correction using CARMA-PACS: high angular resolution observations of the FU Orionis star PP 13S*
We present 0".15 resolution observations of the 227 GHz continuum emission from the circumstellar disk around
the FU Orionis star PP 13S*. The data were obtained with the Combined Array for Research in Millimeter-wave
Astronomy (CARMA) Paired Antenna Calibration System (C-PACS), which measures and corrects the atmospheric
delay fluctuations on the longest baselines of the array in order to improve the sensitivity and angular resolution of
the observations. A description of the C-PACS technique and the data reduction procedures are presented. C-PACS
was applied to CARMA observations of PP 13S*, which led to a factor of 1.6 increase in the observed peak flux
of the source, a 36% reduction in the noise of the image, and a 52% decrease in the measured size of the source
major axis. The calibrated complex visibilities were fitted with a theoretical disk model to constrain the disk surface
density. The total disk mass from the best-fit model corresponds to 0.06 M_â, which is larger than the median mass of a disk around a classical T Tauri star. The disk is optically thick at a wavelength of 1.3 mm for orbital radii less than 48 AU. At larger radii, the inferred surface density of the PP 13S* disk is an order of magnitude lower than that needed to develop a gravitational instability
The double burden of age and disease on cognition and quality of life in bipolar disorder
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/108337/1/gps4084.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/108337/2/gps4084-sup-0002-TableS1.pd
A realtime observatory for laboratory simulation of planetary flows
Motivated by the large-scale circulation of the atmosphere and ocean, we develop a system that uses
observations from a laboratory analog to constrain, in real time, a numerical simulation of the laboratory
flow. This system provides a tool to rapidly prototype new methods for state and parameter
estimation, and facilitates the study of prediction, predictability, and transport of geophysical fluids
where observations or numerical simulations would not independently suffice.
A computer vision system is used to extract measurements of the physical simulation. Observations
are used to constrain the model-state of the MIT General Circulation Model in a probabilistic, ensemble based assimilation approach. Using a combination of parallelism, domain decomposition and an efficient
scheme to select ensembles of model-states, we show that estimates that effectively track the fluid state
can be produced. To the best of our knowledge this is the first such observatory for laboratory
analogs of planetary circulation that functions in real time.National Science Foundation (U.S.) (CNS-0540259)National Science Foundation (U.S.) (grant CNS-0540248
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