188 research outputs found
A Framework for Prioritizing the TESS Planetary Candidates Most Amenable to Atmospheric Characterization
A key legacy of the recently launched TESS mission will be to provide the
astronomical community with many of the best transiting exoplanet targets for
atmospheric characterization. However, time is of the essence to take full
advantage of this opportunity. JWST, although delayed, will still complete its
nominal five year mission on a timeline that motivates rapid identification,
confirmation, and mass measurement of the top atmospheric characterization
targets from TESS. Beyond JWST, future dedicated missions for atmospheric
studies such as ARIEL require the discovery and confirmation of several hundred
additional sub-Jovian size planets (R_p < 10 R_Earth) orbiting bright stars,
beyond those known today, to ensure a successful statistical census of
exoplanet atmospheres. Ground-based ELTs will also contribute to surveying the
atmospheres of the transiting planets discovered by TESS. Here we present a set
of two straightforward analytic metrics, quantifying the expected
signal-to-noise in transmission and thermal emission spectroscopy for a given
planet, that will allow the top atmospheric characterization targets to be
readily identified among the TESS planet candidates. Targets that meet our
proposed threshold values for these metrics would be encouraged for rapid
follow-up and confirmation via radial velocity mass measurements. Based on the
catalog of simulated TESS detections by Sullivan et al. (2015), we determine
appropriate cutoff values of the metrics, such that the TESS mission will
ultimately yield a sample of high-quality atmospheric
characterization targets across a range of planet size bins, extending down to
Earth-size, potentially habitable worlds.Comment: accepted to PAS
JWST-TST DREAMS: Quartz Clouds in the Atmosphere of WASP-17b
Clouds are prevalent in many of the exoplanet atmospheres that have been
observed to date. For transiting exoplanets, we know if clouds are present
because they mute spectral features and cause wavelength-dependent scattering.
While the exact composition of these clouds is largely unknown, this
information is vital to understanding the chemistry and energy budget of
planetary atmospheres. In this work, we observe one transit of the hot Jupiter
WASP-17b with JWST's MIRI LRS and generate a transmission spectrum from 5-12
m. These wavelengths allow us to probe absorption due to the
vibrational modes of various predicted cloud species. Our transmission spectrum
shows additional opacity centered at 8.6 m, and detailed atmospheric
modeling and retrievals identify this feature as SiO(s) (quartz) clouds.
The SiO(s) clouds model is preferred at 3.5-4.2 versus a cloud-free
model and at 2.6 versus a generic aerosol prescription. We find the
SiO(s) clouds are comprised of small m particles,
which extend to high altitudes in the atmosphere. The atmosphere also shows a
depletion of HO, a finding consistent with the formation of
high-temperature aerosols from oxygen-rich species. This work is part of a
series of studies by our JWST Telescope Scientist Team (JWST-TST), in which we
will use Guaranteed Time Observations to perform Deep Reconnaissance of
Exoplanet Atmospheres through Multi-instrument Spectroscopy (DREAMS).Comment: 19 pages, 7 figures, accepted for publication in ApJ
Search for heavy resonances decaying to two Higgs bosons in final states containing four b quarks
A search is presented for narrow heavy resonances X decaying into pairs of Higgs bosons (H) in proton-proton collisions collected by the CMS experiment at the LHC at root s = 8 TeV. The data correspond to an integrated luminosity of 19.7 fb(-1). The search considers HH resonances with masses between 1 and 3 TeV, having final states of two b quark pairs. Each Higgs boson is produced with large momentum, and the hadronization products of the pair of b quarks can usually be reconstructed as single large jets. The background from multijet and t (t) over bar events is significantly reduced by applying requirements related to the flavor of the jet, its mass, and its substructure. The signal would be identified as a peak on top of the dijet invariant mass spectrum of the remaining background events. No evidence is observed for such a signal. Upper limits obtained at 95 confidence level for the product of the production cross section and branching fraction sigma(gg -> X) B(X -> HH -> b (b) over barb (b) over bar) range from 10 to 1.5 fb for the mass of X from 1.15 to 2.0 TeV, significantly extending previous searches. For a warped extra dimension theory with amass scale Lambda(R) = 1 TeV, the data exclude radion scalar masses between 1.15 and 1.55 TeV
Measurement of the top quark mass using charged particles in pp collisions at root s=8 TeV
Peer reviewe
Multiancestry Genome-Wide Association Study of Lipid Levels Incorporating Gene-Alcohol Interactions
A person's lipid profile is influenced by genetic variants and alcohol consumption, but the contribution of interactions between these exposures has not been studied. We therefore incorporated gene-alcohol interactions into a multiancestry genome-wide association study of levels of high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, and triglycerides. We included 45 studies in stage 1 (genome-wide discovery) and 66 studies in stage 2 (focused follow-up), for a total of 394,584 individuals from 5 ancestry groups. Analyses covered the period July 2014-November 2017. Genetic main effects and interaction effects were jointly assessed by means of a 2-degrees-of-freedom (df) test, and a 1-df test was used to assess the interaction effects alone. Variants at 495 loci were at least suggestively associated (P <1 x 10(-6)) with lipid levels in stage 1 and were evaluated in stage 2, followed by combined analyses of stage 1 and stage 2. In the combined analysis of stages 1 and 2, a total of 147 independent loci were associated with lipid levels at P <5 x 10(-8) using 2-df tests, of which 18 were novel. No genome-wide-significant associations were found testing the interaction effect alone. The novel loci included several genes (proprotein convertase subtilisin/kexin type 5 (PCSK5), vascular endothelial growth factor B (VEGFB), and apolipoprotein B mRNA editing enzyme, catalytic polypeptide 1 (APOBEC1) complementation factor (A1CF)) that have a putative role in lipid metabolism on the basis of existing evidence from cellular and experimental models.Peer reviewe
Defining the causes of sporadic Parkinson's disease in the global Parkinson's genetics program (GP2)
The Global Parkinson’s Genetics Program (GP2) will genotype over 150,000 participants from around the world, and integrate genetic and clinical data for use in large-scale analyses to dramatically expand our understanding of the genetic architecture of PD. This report details the workflow for cohort integration into the complex arm of GP2, and together with our outline of the monogenic hub in a companion paper, provides a generalizable blueprint for establishing large scale collaborative research consortia
A multi-ancestry genome-wide study incorporating gene-smoking interactions identifies multiple new loci for pulse pressure and mean arterial pressure
Elevated blood pressure (BP), a leading cause of global morbidity and mortality, is influenced by both genetic and lifestyle factors. Cigarette smoking is one such lifestyle factor. Across five ancestries, we performed a genome-wide gene-smoking interaction study of mean arterial pressure (MAP) and pulse pressure (PP) in 129 913 individuals in stage 1 and follow-up analysis in 480 178 additional individuals in stage 2. We report here 136 loci significantly associated with MAP and/or PP. Of these, 61 were previously published through main-effect analysis of BP traits, 37 were recently reported by us for systolic BP and/or diastolic BP through gene-smoking interaction analysis and 38 were newly identified (P <5 x 10(-8), false discovery rate <0.05). We also identified nine new signals near known loci. Of the 136 loci, 8 showed significant interaction with smoking status. They include CSMD1 previously reported for insulin resistance and BP in the spontaneously hypertensive rats. Many of the 38 new loci show biologic plausibility for a role in BP regulation. SLC26A7 encodes a chloride/bicarbonate exchanger expressed in the renal outer medullary collecting duct. AVPR1A is widely expressed, including in vascular smooth muscle cells, kidney, myocardium and brain. FHAD1 is a long non-coding RNA overexpressed in heart failure. TMEM51 was associated with contractile function in cardiomyocytes. CASP9 plays a central role in cardiomyocyte apoptosis. Identified only in African ancestry were 30 novel loci. Our findings highlight the value of multi-ancestry investigations, particularly in studies of interaction with lifestyle factors, where genomic and lifestyle differences may contribute to novel findings.Peer reviewe
Three-dimensional modeling of shallow shear-wave velocities for Las Vegas, Nevada, using sediment type
Supercharged green fluorescent proteins as bimodal reporter genes for CEST MRI and optical imaging
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2019 Update of the American College of Rheumatology/Spondylitis Association of America/Spondyloarthritis Research and Treatment Network Recommendations for the Treatment of Ankylosing Spondylitis and Nonradiographic Axial Spondyloarthritis
ObjectiveTo update evidence-based recommendations for the treatment of patients with ankylosing spondylitis (AS) and nonradiographic axial spondyloarthritis (SpA).MethodsWe conducted updated systematic literature reviews for 20 clinical questions on pharmacologic treatment addressed in the 2015 guidelines, and for 26 new questions on pharmacologic treatment, treat-to-target strategy, and use of imaging. New questions addressed the use of secukinumab, ixekizumab, tofacitinib, tumor necrosis factor inhibitor (TNFi) biosimilars, and biologic tapering/discontinuation, among others. We used the Grading of Recommendations, Assessment, Development and Evaluation methodology to assess the quality of evidence and formulate recommendations and required at least 70% agreement among the voting panel.ResultsRecommendations for AS and nonradiographic axial SpA are similar. TNFi are recommended over secukinumab or ixekizumab as the first biologic to be used. Secukinumab or ixekizumab is recommended over the use of a second TNFi in patients with primary nonresponse to the first TNFi. TNFi, secukinumab, and ixekizumab are favored over tofacitinib. Co-administration of low-dose methotrexate with TNFi is not recommended, nor is a strict treat-to-target strategy or discontinuation or tapering of biologics in patients with stable disease. Sulfasalazine is recommended only for persistent peripheral arthritis when TNFi are contraindicated. For patients with unclear disease activity, spine or pelvis magnetic resonance imaging could aid assessment. Routine monitoring of radiographic changes with serial spine radiographs is not recommended.ConclusionThese recommendations provide updated guidance regarding use of new medications and imaging of the axial skeleton in the management of AS and nonradiographic axial SpA
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