262 research outputs found
Spitzer Warm Mission Transition and Operations
Following the successful dynamic planning and implementation of IRAC Warm Instrument Characterization activities, transition to Spitzer Warm Mission operations has gone smoothly. Operation teams procedures and processes required minimal adaptation and the overall composition of the Mission Operation System retained the same functionality it had during the Cryogenic Mission. While the warm mission scheduling has been simplified because all observations are now being made with a single instrument, several other differences have increased the complexity. The bulk of the observations executed to date have been from ten large Exploration Science programs that, combined, have more complex constraints, more observing requests, and more exo-planet observations with durations of up to 145 hours. Communication with the observatory is also becoming more challenging as the Spitzer DSN antenna allocations have been reduced from two tracking passes per day to a single pass impacting both uplink and downlink activities. While IRAC is now operating with only two channels, the data collection rate is roughly 60% of the four-channel rate leaving a somewhat higher average volume collected between the less frequent passes. Also, the maximum downlink data rate is decreasing as the distance to Spitzer increases requiring longer passes. Nevertheless, with well over 90% of the time spent on science observations, efficiency has equaled or exceeded that achieved during the cryogenic mission
Diastolic dysfunction and left atrial volume A population-based study
ObjectivesWe examined the association between diastolic function and left atrial volume indexed to body surface area (LAVi) in a population-based study.BackgroundAtrial enlargement has been suggested as a marker of the severity and duration of diastolic dysfunction (DD). However, the association between DD and atrial enlargement and their individual prognostic implications in the population is poorly defined.MethodsA cross-sectional sample of Olmsted County, Minnesota, residents ≥45 years of age (n = 2,042) underwent comprehensive Doppler echocardiography and medical record review.ResultsThe LAVi increased with worsening DD: 23 ± 6 ml/m2(normal), 25 ± 8 ml/m2(grade I DD), 31 ± 8 ml/m2(grade II DD), 48 ± 12 ml/m2(grades III to IV DD). In bivariate analyses, age, left ventricular mass index, and DD grade were positively associated, whereas female gender and ejection fraction (EF) were inversely associated with LAVi (p < 0.001 for all). When controlling for age, gender, cardiovascular (CV) disease, EF, and left ventricular mass, grade II DD was associated with a 24%, and grade III to IV DD was associated with a 62% larger LA volume (p < 0.0001 for both). The area under the receiver-operator characteristic curve for LAVi to detect grade I, grade II, or grade III to IV DD was 0.57, 0.81, and 0.98, respectively. Both DD and LAVi were predictive of all-cause mortality, but when controlling for DD, LAVi was not an independent predictor of mortality.ConclusionsThese data suggest that DD contributes to LA remodeling. Indeed, DD is a stronger predictor of mortality; presumably it better reflects the impact of CV disease within the general population
Sex differences and survival in adults with bicuspid aortic valves : verification in 3 contemporary echocardiographic cohorts
Background-—Sex-related differences in morbidity and survival in bicuspid aortic valve (BAV) adults are fundamentally unknown.
Contemporary studies portend excellent survival for BAV patients identified at early echocardiographic-clinical stages. Whether
BAV adults incur a survival disadvantage throughout subsequent echocardiographic-clinical stages remains undetermined.
Methods and Results-—Analysis was done of 3 different cohorts of consecutive patients with echocardiographic diagnosis of BAV
identified retrospectively: (1) a community cohort of 416 patients with first BAV diagnosis (age 35 21 years, follow-up
16 7 years), (2) a tertiary clinical referral cohort of 2824 BAV adults (age 51 16 years, follow-up 9 6 years), and (3) a surgical
referral cohort of 2242 BAV adults referred for aortic valve replacement (AVR) (age 62 14 years, follow-up 6 5 years). For the
community cohort, 20-year risks of aortic regurgitation (AR), AVR, and infective endocarditis were higher in men (all P=0.04); for a
total BAV-related morbidity risk of 52 4% vs 35 6% in women (P=0.01). The cohort’s 25-year survival was identical to that in the
general population (P=0.98). AR independently predicted mortality in women (P=0.001). Baseline AR was more common in men
(P=0.02) in the tertiary cohort, with 20-year survival lower than that in the general population (P<0.0001); age-adjusted relative
death risk was 1.16 (95% confidence interval [CI] 1.05-1.29) for men versus 1.67 (95% CI 1.38-2.03) for women (P=0.001). AR
independently predicted mortality in women (P=0.01). Baseline AR and infective endocarditis were higher in men (both =0.001) for
the surgical referral cohort, with 15-year survival lower than that in the general population (P<0.0001); age-adjusted relative death
risk was 1.34 (95% CI 1.22-1.47) for men versus 1.63 (95% CI 1.40-1.89) for women (P=0.026). AR and NYHA class independently
predicted mortality in women (both P=0.04).
Conclusions-—Within evolving echocardiographic-clinical stages, the long-term survival of adults with BAV is not benign, as both
men and women incur excess mortality. Although BAV-related morbidity is higher in men in the community, and AR and infective
endocarditis are more prevalent in men, women exhibit a significantly higher relative risk of death in tertiary and surgical referral
cohorts, which is independently associated with A
Spitzer operations: scheduling the out years
Spitzer Warm Mission operations have remained robust and exceptionally efficient since the cryogenic mission ended in mid-2009. The distance to the observatory now exceeds 1 AU, making telecommunications increasingly difficult; however, analysis has shown that two-way communication could be maintained through at least 2017 with minimal loss in observing efficiency. The science program continues to emphasize the characterization of exoplanets, time domain studies, and deep surveys, all of which can impose interesting scheduling constraints. Recent changes have significantly improved on-board data compression, which both enables certain high volume observations and reduces Spitzer's demand for competitive Deep Space Network resources
Dengue Vaccines Regulatory Pathways: A Report on Two Meetings with Regulators of Developing Countries
Richard Mahoney and colleagues summarize two recent meetings convened by the Pediatric Dengue Vaccine Initiative and the Developing Countries' Vaccine Regulators Network on regulatory issues that need to be addressed before licensing dengue vaccines
macroH2A2 antagonizes epigenetic programs of stemness in glioblastoma
Self-renewal is a crucial property of glioblastoma cells that is enabled by the choreographed functions of chromatin regulators and transcription factors. Identifying targetable epigenetic mechanisms of self-renewal could therefore represent an important step toward developing effective treatments for this universally lethal cancer. Here we uncover an epigenetic axis of self-renewal mediated by the histone variant macroH2A2. With omics and functional assays deploying patient-derived in vitro and in vivo models, we show that macroH2A2 shapes chromatin accessibility at enhancer elements to antagonize transcriptional programs of self-renewal. macroH2A2 also sensitizes cells to small molecule-mediated cell death via activation of a viral mimicry response. Consistent with these results, our analyses of clinical cohorts indicate that high transcriptional levels of this histone variant are associated with better prognosis of high-grade glioma patients. Our results reveal a targetable epigenetic mechanism of self-renewal controlled by macroH2A2 and suggest additional treatment approaches for glioblastoma patients
The Maunakea Spectroscopic Explorer Book 2018
(Abridged) This is the Maunakea Spectroscopic Explorer 2018 book. It is
intended as a concise reference guide to all aspects of the scientific and
technical design of MSE, for the international astronomy and engineering
communities, and related agencies. The current version is a status report of
MSE's science goals and their practical implementation, following the System
Conceptual Design Review, held in January 2018. MSE is a planned 10-m class,
wide-field, optical and near-infrared facility, designed to enable
transformative science, while filling a critical missing gap in the emerging
international network of large-scale astronomical facilities. MSE is completely
dedicated to multi-object spectroscopy of samples of between thousands and
millions of astrophysical objects. It will lead the world in this arena, due to
its unique design capabilities: it will boast a large (11.25 m) aperture and
wide (1.52 sq. degree) field of view; it will have the capabilities to observe
at a wide range of spectral resolutions, from R2500 to R40,000, with massive
multiplexing (4332 spectra per exposure, with all spectral resolutions
available at all times), and an on-target observing efficiency of more than
80%. MSE will unveil the composition and dynamics of the faint Universe and is
designed to excel at precision studies of faint astrophysical phenomena. It
will also provide critical follow-up for multi-wavelength imaging surveys, such
as those of the Large Synoptic Survey Telescope, Gaia, Euclid, the Wide Field
Infrared Survey Telescope, the Square Kilometre Array, and the Next Generation
Very Large Array.Comment: 5 chapters, 160 pages, 107 figure
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