28 research outputs found
Microlensing Constraints on Broad Absorption and Emission Line Flows in the Quasar H1413+117
We present new integral field spectroscopy of the gravitationally lensed
broad absorption line (BAL) quasar H1413+117, covering the ultraviolet to
visible rest-frame spectral range. We observe strong microlensing signatures in
lensed image D, and we use this microlensing to simultaneously constrain both
the broad emission and broad absorption line gas. By modeling the lens system
over the range of probable lensing galaxy redshifts and using on a new argument
based on the wavelength-independence of the broad line lensing magnifications,
we determine that there is no significant broad line emission from smaller than
~20 light days. We also perform spectral decomposition to derive the intrinsic
broad emission line (BEL) and continuum spectrum, subject to BAL absorption. We
also reconstruct the intrinsic BAL absorption profile, whose features allow us
to constrain outflow kinematics in the context of a disk-wind model. We find a
very sharp, blueshifted onset of absorption of 1,500 km/s in both C IV and N V
that may correspond to an inner edge of a disk-wind's radial outflow. The lower
ionization Si IV and Al III have higher-velocity absorption onsets, consistent
with a decreasing ionization parameter with radius in an accelerating outflow.
There is evidence of strong absorption in the BEL component which indicates a
high covering factor for absorption over two orders of magnitude in outflow
radius.Comment: 29 pages, 8 figure
Comparing the unmatched count technique and direct self-report for sensitive health-risk behaviors in HIV+ adults
Researchers often rely on self-report measures to assess sensitive health-risk behaviors in HIV+ individuals, yet the accuracy of self-report has been questioned, particularly when inquiring about behaviors that may be embarrassing, risky, and/or taboo. We compared an anonymous reporting method—the Unmatched Count Technique (UCT)—to direct self-report in order to assess reporting differences for several health-risk behaviors related to medication adherence and sexual risk. Contrary to hypotheses, the UCT only produced a significantly higher estimated base rate for one sensitive behavior: reporting medication adherence to one\u27s physician, which may have been contextually-primed by our study design. Our results suggest that anonymous reporting methods may not increase disclosure compared to direct self-report when assessing several health-risk behaviors in HIV+ research volunteers. However, our results also suggest that contextual factors should be considered and investigated further, as they may influence perception of sensitive behavior
Unified understanding of intrinsic and extrinsic controls of dissolved organic carbon reactivity in aquatic ecosystems
Despite our growing understanding of the global carbon cycle, scientific consensus on the drivers and mechanisms that control dissolved organic carbon (DOC) turnover in aquatic systems is lacking, hampered by the mismatch between research that approaches DOC reactivity from either intrinsic (inherent chemical properties) or extrinsic (environmental context) perspectives. Here we propose a conceptual view of DOC reactivity in which the combination of intrinsic and extrinsic factors controls turnover rates and determines which reactions will occur. We review three major types of reactions (biological, photochemical, and flocculation) from an intrinsic chemical perspective and further define the environmental features that modulate the expression of chemically inherent reactivity potential. Finally, we propose hypotheses of how extrinsic and intrinsic factors together shape patterns in DOC turnover across the land-to-ocean continuum, underscoring that there is no intrinsic DOC reactivity without environmental context. By acknowledging the intrinsic–extrinsic control duality, our framework intends to foster improved modeling of DOC reactivity and its impact on ecosystem services.publishedVersio
Unified understanding of intrinsic and extrinsic controls of dissolved organic carbon reactivity in aquatic ecosystems
Despite our growing understanding of the global carbon cycle, scientific consensus on the drivers and mechanisms that control dissolved organic carbon (DOC) turnover in aquatic systems is lacking, hampered by the mismatch between research that approaches DOC reactivity from either intrinsic (inherent chemical properties) or extrinsic (environmental context) perspectives. Here we propose a conceptual view of DOC reactivity in which the combination of intrinsic and extrinsic factors controls turnover rates and determines which reactions will occur. We review three major types of reactions (biological, photochemical, and flocculation) from an intrinsic chemical perspective and further define the environmental features that modulate the expression of chemically inherent reactivity potential. Finally, we propose hypotheses of how extrinsic and intrinsic factors together shape patterns in DOC turnover across the land-to-ocean continuum, underscoring that there is no intrinsic DOC reactivity without environmental context. By acknowledging the intrinsic–extrinsic control duality, our framework intends to foster improved modeling of DOC reactivity and its impact on ecosystem services
SPLUS J142445.34-254247.1: An R-Process Enhanced, Actinide-Boost, Extremely Metal-Poor star observed with GHOST
We report on the chemo-dynamical analysis of SPLUS J142445.34-254247.1, an
extremely metal-poor halo star enhanced in elements formed by the rapid
neutron-capture process. This star was first selected as a metal-poor candidate
from its narrow-band S-PLUS photometry and followed up spectroscopically in
medium-resolution with Gemini South/GMOS, which confirmed its low-metallicity
status. High-resolution spectroscopy was gathered with GHOST at Gemini South,
allowing for the determination of chemical abundances for 36 elements, from
carbon to thorium. At [Fe/H]=-3.39, SPLUS J1424-2542 is one of the lowest
metallicity stars with measured Th and has the highest logeps(Th/Eu) observed
to date, making it part of the "actinide-boost" category of r-process enhanced
stars. The analysis presented here suggests that the gas cloud from which SPLUS
J1424-2542 was formed must have been enriched by at least two progenitor
populations. The light-element (Z<=30) abundance pattern is consistent with the
yields from a supernova explosion of metal-free stars with 11.3-13.4 Msun, and
the heavy-element (Z>=38) abundance pattern can be reproduced by the yields
from a neutron star merger (1.66Msun and 1.27Msun) event. A kinematical
analysis also reveals that SPLUS J1424-2542 is a low-mass, old halo star with a
likely in-situ origin, not associated with any known early merger events in the
Milky Way.Comment: 26 pages, 11 figures, accepted for publication on Ap
Estrogenic botanical supplements, health-related quality of life, fatigue, and hormone-related symptoms in breast cancer survivors: a HEAL study report
<p>Abstract</p> <p>Background</p> <p>It remains unclear whether estrogenic botanical supplement (EBS) use influences breast cancer survivors' health-related outcomes.</p> <p>Methods</p> <p>We examined the associations of EBS use with health-related quality of life (HRQOL), with fatigue, and with 15 hormone-related symptoms such as hot flashes and night sweats among 767 breast cancer survivors participating in the Health, Eating, Activity, and Lifestyle (HEAL) Study. HRQOL was measured by the Medical Outcomes Study short form-36 physical and mental component scale summary score. Fatigue was measured by the Revised-Piper Fatigue Scale score.</p> <p>Results</p> <p>Neither overall EBS use nor the number of EBS types used was associated with HRQOL, fatigue, or hormone-related symptoms. However, comparisons of those using each specific type of EBS with non-EBS users revealed the following associations. Soy supplements users were more likely to have a better physical health summary score (odds ratio [OR] = 1.66, 95% confidence interval [CI] = 1.02-2.70). Flaxseed oil users were more likely to have a better mental health summary score (OR = 1.76, 95% CI = 1.05-2.94). Ginseng users were more likely to report severe fatigue and several hormone-related symptoms (all ORs ≥ 1.7 and all 95% CIs exclude 1). Red clover users were less likely to report weight gain, night sweats, and difficulty concentrating (all OR approximately 0.4 and all 95% CIs exclude 1). Alfalfa users were less likely to experience sleep interruption (OR = 0.28, 95% CI = 0.12-0.68). Dehydroepiandrosterone users were less likely to have hot flashes (OR = 0.33, 95% CI = 0.14-0.82).</p> <p>Conclusions</p> <p>Our findings indicate that several specific types of EBS might have important influences on a woman's various aspects of quality of life, but further verification is necessary.</p
Data reduction software for the Gemini high resolution optical spectrograph
The data reduction software for the Gemini High Resolution Optical SpecTrograph (GHOST) presents a number of unusual challenges. Star light from one or two objects and simultaneous sky is collected in integral field units rather than a slit or well-separated fibers. When used with binning, individual fibers are not resolved, and the optimal pixel weighting is derived from a simultaneous slit viewing camera. We describe the data reduction approach taken, including testing using an optical physics-based data simulator, and an object-oriented and modular approach to spectral extraction that fits within the Gemini recipe system, DRAGONS, using AstroConda