1,092 research outputs found
Spitzer Phase Curves of KELT-1b and the Signatures of Nightside Clouds in Thermal Phase Observations
We observed two full orbital phase curves of the transiting brown dwarf
KELT-1b, at 3.6um and 4.5um, using the Spitzer Space Telescope. Combined with
previous eclipse data from Beatty et al. (2014), we strongly detect KELT-1b's
phase variation as a single sinusoid in both bands, with amplitudes of
ppm at 3.6um and ppm at 4.5um, and confirm the secondary
eclipse depths measured by Beatty et al. (2014). We also measure noticeable
Eastward hotspot offsets of degrees at 3.6um and
degrees at 4.5um. Both the day-night temperature contrasts and the hotspot
offsets we measure are in line with the trends seen in hot Jupiters (e.g.,
Crossfield 2015), though we disagree with the recent suggestion of an offset
trend by Zhang et al. (2018). Using an ensemble analysis of Spitzer phase
curves, we argue that nightside clouds are playing a noticeable role in
modulating the thermal emission from these objects, based on: 1) the lack of a
clear trend in phase offsets with equilibrium temperature, 2) the sharp
day-night transitions required to have non-negative intensity maps, which also
resolves the inversion issues raised by Keating & Cowan (2017), 3) the fact
that all the nightsides of these objects appear to be at roughly the same
temperature of 1000K, while the dayside temperatures increase linearly with
equilibrium temperature, and 4) the trajectories of these objects on a Spitzer
color-magnitude diagram, which suggest colors only explainable via nightside
clouds.Comment: AJ in press. Updated to reflect the accepted versio
Selective Serotonin Reuptake Inhibitors and Associated Bleeding Risks: A Narrative and Clinical Review.
Major Depressive Disorder (MDD) is a major cause of disability worldwide and is associated with serious lasting impairment. A leading hypothesis of the pathophysiology of MDD is the monoamine deficiency hypothesis which suggests that depression is caused by depletion of serotonin, norepinephrine, or dopamine in the central nervous system. Serotonin is the most widely studied neurotransmitter in the pathophysiology of depression, with studies showing that reduced central serotonin synthesis leads to depressive symptoms in individuals at risk for depression. Selective Serotonin Reuptake Inhibitors (SSRI) inhibit serotonin reuptake and subsequently increase the amount of serotonin available in synapses. Common side effects of SSRIs include increased suicidality of patients under the age of 25, sexual dysfunction, anxiety, dizziness, weight gain, gastrointestinal distress, and headache. Other side effects include prolonging the QT interval, coagulopathy, and the risk of serotonin syndrome, as well as SSRI discontinuation syndrome. Sites of increased bleeding related to SSRI use have been reported to occur in the upper gastrointestinal tract, as well as intracranially. Based on the current literature, three studies have found that SSRIs are not associated with increased bleeding and/or increased perioperative risk, while others have demonstrated that SSRIs are associated with an increased risk in perioperative use. The inhibition of serotonin reuptake can affect platelet aggregation since platelets also express the serotonin transporter. SSRIs can result in decreased storage of serotonin in platelet dense granules. Increased serotonin can also increase gastric acid secretion, which increases the risk for ulceration. SSRIs in combination with NSAIDs also show a significantly increased risk of upper GI bleeding. Some studies show an increased bleeding risk from 30% to 70% when taking a combination of vitamin K antagonists and SSRIs in hospitalized patients. Related to the high prevalence of conditions that are treated with SSRIs, the bleeding risk associated with this class of medication merits further study
KELT-7b: A hot Jupiter transiting a bright V=8.54 rapidly rotating F-star
We report the discovery of KELT-7b, a transiting hot Jupiter with a mass of
MJ, radius of RJ, and an orbital
period of days. The bright host star (HD33643;
KELT-7) is an F-star with , Teff K, [Fe/H]
, and . It has a mass of
Msun, a radius of Rsun, and
is the fifth most massive, fifth hottest, and the ninth brightest star known to
host a transiting planet. It is also the brightest star around which KELT has
discovered a transiting planet. Thus, KELT-7b is an ideal target for detailed
characterization given its relatively low surface gravity, high equilibrium
temperature, and bright host star. The rapid rotation of the star (
km/s) results in a Rossiter-McLaughlin effect with an unusually large amplitude
of several hundred m/s. We find that the orbit normal of the planet is likely
to be well-aligned with the stellar spin axis, with a projected spin-orbit
alignment of degrees. This is currently the second most
rapidly rotating star to have a reflex signal (and thus mass determination) due
to a planetary companion measured.Comment: Accepted to The Astronomical Journa
KELT-11b: A Highly Inflated Sub-Saturn Exoplanet Transiting the V=8 Subgiant HD 93396
We report the discovery of a transiting exoplanet, KELT-11b, orbiting the
bright () subgiant HD 93396. A global analysis of the system shows that
the host star is an evolved subgiant star with K,
, , log , and [Fe/H].
The planet is a low-mass gas giant in a day orbit,
with , , g cm, surface gravity log , and equilibrium temperature K. KELT-11 is the brightest known transiting exoplanet host
in the southern hemisphere by more than a magnitude, and is the 6th brightest
transit host to date. The planet is one of the most inflated planets known,
with an exceptionally large atmospheric scale height (2763 km), and an
associated size of the expected atmospheric transmission signal of 5.6%. These
attributes make the KELT-11 system a valuable target for follow-up and
atmospheric characterization, and it promises to become one of the benchmark
systems for the study of inflated exoplanets.Comment: 15 pages, Submitted to AAS Journal
The effectiveness evaluation of a multimedia hepatitis C prevention program for Hispanic HIV-infected individuals
Introduction—With the introduction of highly active antiretroviral therapy the Hepatitis C virus
(HCV) infection has became a primary health problem among individuals suffering from HIV/
AIDS in Puerto Rico, principally those who are injecting drug users (IDUs). A multimedia
educational intervention, based on the Health Beliefs Model and Social Cognitive Theory was
developed and implemented to reduce HCV associated risk behaviors among IDUs.
Methods—A pre- and post- intervention study evaluated the knowledge and behavioral changes
in a group of HIV-infected persons recruited from February 2006 through December 2008.
Results—A total of 110 participants were recruited; all were IDUs; 82% were men; 86.3% were
HIV/HCV co-infected and 24.5% had active injected drugs in the last month (prior to
recruitment). The group mean age was 42.2 ± 9.2 years and mean educational level was 10th
grade. Knowledge of HCV risk behaviors, perception of HCV susceptibility, and perception of
disease severity increased after the intervention. Knowledge of HCV clinical manifestations and
HIV co-infection complications and treatment also improved. In addition, HCV risk behaviors and
injecting drug practice decrease significantly among IDUs.
Conclusions—This new multimedia intervention captured and maintained the participants'
attention and interest, in that way facilitating their educational process. Thus, a greater of attention
and interest leads to greater knowledge and prevention improvement
Colorectal cancer linkage on chromosomes 4q21, 8q13, 12q24, and 15q22
A substantial proportion of familial colorectal cancer (CRC) is not a consequence of known susceptibility loci, such as mismatch repair (MMR) genes, supporting the existence of additional loci. To identify novel CRC loci, we conducted a genome-wide linkage scan in 356 white families with no evidence of defective MMR (i.e., no loss of tumor expression of MMR proteins, no microsatellite instability (MSI)-high tumors, or no evidence of linkage to MMR genes). Families were ascertained via the Colon Cancer Family Registry multi-site NCI-supported consortium (Colon CFR), the City of Hope Comprehensive Cancer Center, and Memorial University of Newfoundland. A total of 1,612 individuals (average 5.0 per family including 2.2 affected) were genotyped using genome-wide single nucleotide polymorphism linkage arrays; parametric and non-parametric linkage analysis used MERLIN in a priori-defined family groups. Five lod scores greater than 3.0 were observed assuming heterogeneity. The greatest were among families with mean age of diagnosis less than 50 years at 4q21.1 (dominant HLOD = 4.51, α = 0.84, 145.40 cM, rs10518142) and among all families at 12q24.32 (dominant HLOD = 3.60, α = 0.48, 285.15 cM, rs952093). Among families with four or more affected individuals and among clinic-based families, a common peak was observed at 15q22.31 (101.40 cM, rs1477798; dominant HLOD = 3.07, α = 0.29; dominant HLOD = 3.03, α = 0.32, respectively). Analysis of families with only two affected individuals yielded a peak at 8q13.2 (recessive HLOD = 3.02, α = 0.51, 132.52 cM, rs1319036). These previously unreported linkage peaks demonstrate the continued utility of family-based data in complex traits and suggest that new CRC risk alleles remain to be elucidated. © 2012 Cicek et al
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