56 research outputs found
Time variation of Kepler transits induced by stellar spots - a way to distinguish between prograde and retrograde motion. II. Application to KOIs
Mazeh, Holczer, and Shporer (2015) have presented an approach that can, in
principle, use the derived transit timing variation (TTV) of some transiting
planets observed by the mission to distinguish between prograde and
retrograde motion of their orbits with respect to their parent stars' rotation.
The approach utilizes TTVs induced by spot-crossing events that occur when the
planet moves across a spot on the stellar surface, looking for a correlation
between the derived TTVs and the stellar brightness derivatives at the
corresponding transits. This can work even in data that cannot temporally
resolve the spot-crossing events themselves. Here we apply this approach to the
KOIs, identifying nine systems where the photometric spot modulation
is large enough and the transit timing accurate enough to allow detection of a
TTV-brightness-derivatives correlation. Of those systems five show highly
significant prograde motion (Kepler-17b, Kepler-71b, KOI-883.01, KOI-895.01,
and KOI-1074.01), while no system displays retrograde motion, consistent with
the suggestion that planets orbiting cool stars have prograde motion. All five
systems have impact parameter , and all systems
within that impact parameter range show significant correlation, except
HAT-P-11b where the lack of a correlation follows its large stellar obliquity.
Our search suffers from an observational bias against detection of high impact
parameter cases, and the detected sample is extremely small. Nevertheless, our
findings may suggest that stellar spots, or at least the larger ones, tend to
be located at a low stellar latitude, but not along the stellar equator,
similar to the Sun.Comment: V2: accepted to Ap
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Cerebral Microdialysate Metabolite Monitoring using Mid-infrared Spectroscopy.
Funder: Wellcome TrustThe brains of patients suffering from traumatic brain-injury (TBI) undergo dynamic chemical changes in the days following the initial trauma. Accurate and timely monitoring of these changes is of paramount importance for improved patient outcome. Conventional brain-chemistry monitoring is performed off-line by collecting and manually transferring microdialysis samples to an enzymatic colorimetric bedside analyzer every hour, which detects and quantifies the molecules of interest. However, off-line, hourly monitoring means that any subhourly neurochemical changes, which may be detrimental to patients, go unseen and thus untreated. Mid-infrared (mid-IR) spectroscopy allows rapid, reagent-free, molecular fingerprinting of liquid samples, and can be easily integrated with microfluidics. We used mid-IR transmission spectroscopy to analyze glucose, lactate, and pyruvate, three relevant brain metabolites, in the extracellular brain fluid of two TBI patients, sampled via microdialysis. Detection limits of 0.5, 0.2, and 0.1 mM were achieved for pure glucose, lactate, and pyruvate, respectively, in perfusion fluid using an external cavity-quantum cascade laser (EC-QCL) system with an integrated transmission flow-cell. Microdialysates were collected hourly, then pooled (3-4 h), and measured consecutively using the standard ISCUSflex analyzer and the EC-QCL system. There was a strong correlation between the compound concentrations obtained using the conventional bedside analyzer and the acquired mid-IR absorbance spectra, where a partial-least-squares regression model was implemented to compute concentrations. This study demonstrates the potential utility of mid-IR spectroscopy for continuous, automated, reagent-free, and online monitoring of the dynamic chemical changes in TBI patients, allowing a more timely response to adverse brain metabolism and consequently improving patient outcomes
Understanding Galaxy Formation via Near-Infrared Surveys in the 2020s
A discussion of science cases in extragalactic astrophysics and galaxy formation that wide-area space-based infrared surveys will address in the 2020s. <p/
Extreme damped Lyman- absorption in young star-forming galaxies at
The onset of galaxy formation is thought to be initiated by the infall of
neutral, pristine gas onto the first protogalactic halos. However, direct
constraints on the abundance of neutral atomic hydrogen (HI) in galaxies have
been difficult to obtain at early cosmic times. Here we present spectroscopic
observations with JWST of three galaxies at redshifts , about
Myr after the Big Bang, that show strong damped Lyman-
absorption ( cm) from HI in their local
surroundings, an order of magnitude in excess of the Lyman- absorption
caused by the neutral intergalactic medium at these redshifts. Consequently,
these early galaxies cannot be contributing significantly to reionization, at
least at their current evolutionary stages. Simulations of galaxy formation
show that such massive gas reservoirs surrounding young galaxies so early in
the history of the universe is a signature of galaxy formation in progress.Comment: Submitte
Clinical Sequencing Exploratory Research Consortium: Accelerating Evidence-Based Practice of Genomic Medicine
Despite rapid technical progress and demonstrable effectiveness for some types of diagnosis and therapy, much remains to be learned about clinical genome and exome sequencing (CGES) and its role within the practice of medicine. The Clinical Sequencing Exploratory Research (CSER) consortium includes 18 extramural research projects, one National Human Genome Research Institute (NHGRI) intramural project, and a coordinating center funded by the NHGRI and National Cancer Institute. The consortium is exploring analytic and clinical validity and utility, as well as the ethical, legal, and social implications of sequencing via multidisciplinary approaches; it has thus far recruited 5,577 participants across a spectrum of symptomatic and healthy children and adults by utilizing both germline and cancer sequencing. The CSER consortium is analyzing data and creating publically available procedures and tools related to participant preferences and consent, variant classification, disclosure and management of primary and secondary findings, health outcomes, and integration with electronic health records. Future research directions will refine measures of clinical utility of CGES in both germline and somatic testing, evaluate the use of CGES for screening in healthy individuals, explore the penetrance of pathogenic variants through extensive phenotyping, reduce discordances in public databases of genes and variants, examine social and ethnic disparities in the provision of genomics services, explore regulatory issues, and estimate the value and downstream costs of sequencing. The CSER consortium has established a shared community of research sites by using diverse approaches to pursue the evidence-based development of best practices in genomic medicine
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