203 research outputs found
Comparison of rip current hazard likelihood forecasts with observed rip current speeds
Author Posting. © American Meteorological Society, 2017. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Weather and Forecasting 32 (2017): 1659-1666, doi:10.1175/WAF-D-17-0076.1.Although rip currents are a major hazard for beachgoers, the relationship between the danger to swimmers and the physical properties of rip current circulation is not well understood. Here, the relationship between statistical model estimates of hazardous rip current likelihood and in situ velocity observations is assessed. The statistical model is part of a forecasting system that is being made operational by the National Weather Service to predict rip current hazard likelihood as a function of wave conditions and water level. The temporal variability of rip current speeds (offshore-directed currents) observed on an energetic sandy beach is correlated with the hindcasted hazard likelihood for a wide range of conditions. High likelihoods and rip current speeds occurred for low water levels, nearly shore-normal wave angles, and moderate or larger wave heights. The relationship between modeled hazard likelihood and the frequency with which rip current speeds exceeded a threshold was assessed for a range of threshold speeds. The frequency of occurrence of high (threshold exceeding) rip current speeds is consistent with the modeled probability of hazard, with a maximum Brier skill score of 0.65 for a threshold speed of 0.23 m sâ1, and skill scores greater than 0.60 for threshold speeds between 0.15 and 0.30 m sâ1. The results suggest that rip current speed may be an effective proxy for hazard level and that speeds greater than ~0.2 m sâ1 may be hazardous to swimmers.Funding was provided by the National Science Foundation
(1232910, 1332705, and 1536365), and by National
Security Science and Engineering and Vannevar
Bush Faculty Fellowships funded by the assistant secretary
of Defense for Research and Engineering.2018-02-2
Episodic memories among irritable bowel syndrome (IBS) patients: An important aspect of the IBS symptom experience
Objective: Some IBS patients possess detailed memories of the events surrounding their bowel symptom onset ( episodic memories ). In this exploratory study we sought to: (1) examine memory relationship with gastrointestinal (GI) symptom severity, extraintestinal symptoms, and mood; (2) qualitatively explore memory valence and content in IBS patients with or without episodic memories.
Methods: Referral IBS patients
Results: 14/29 (48.3%) of IBS subjects endorsed episodic memories of IBS symptom onset, often GI infections/enteritis (35.7%). Recall of the exact year (69%) and month (60%) of symptom onset were common. Episodic memories were associated with greater IBS symptom severity/bother, higher anxiety/depression, and poorer HRQOL. Though AMT and SCEPT memory specificity were not different based on episodic memories, overgeneralization to negatively-valenced cues in the AMT was associated with more severe IBS in those without episodic memory. Qualitative analysis revealed no observable differences in topic focus of IBS patients with and without episodic memories.
Conclusions: IBS patients often endorse episodic memories associated with symptom onset, and this recall seems to associate with more severe symptoms. Overgeneralization responses to negative stimuli may lead to worse bowel symptoms in those without episodic memories. IBS memory specificity may associate with qualitative differences in processing psychosocial experiences and might be important to IBS pathophysiology
Dissemination and Sustainability of a Hospital-Wide Hand Hygiene Program Emphasizing Positive Reinforcement
Objective. To increase and sustain hospital-wide compliance with hand hygiene through a long-term ongoing multidimensional improvement program emphasizing behavioral factors. Design. Quasi-experimental short study (August 2000-November 2001) and descriptive time series (April 2003-December 2006). Setting. A 450-bed teaching tertiary-care hospital. Interventions. An initial intervention bundle was introduced in pilot locations that addressed cognitive behavioral factors, which included access to alcohol sanitizer, education, and ongoing audit and feedback. The bundle was subsequently disseminated hospital-wide, along with a novel approach focused on behavior modification through positive reinforcement and annually changing incentives. Results. A total of 36,123 hand hygiene opportunities involving all categories of healthcare workers from 12 inpatient units were observed from October 2000 to October 2006. The rate of compliance with hand hygiene significantly improved after the intervention in 2 cohorts over the first year (from 40% to 64% of opportunities and from 34% to 49% of opportunities; P< .001, compared with the control group). Mean compliance rates ranged from 19% to 41% of 4174 opportunities (at baseline), increased to the highest levels of 73%-84% of 6,420 opportunities 2 years after hospital-wide dissemination, and remained improved at 59%-81% of 4,990 opportunities during year 6 of the program. Conclusion. This interventional cohort study used a behavioral change approach and is one of the earliest and largest institution-wide programs promoting alcohol sanitizer from the United States that has shown significant and sustained improvements in hand hygiene compliance. This creative campaign used ongoing frequent audit and feedback with novel use of immediate positive reinforcement at an acceptable cost to the institutio
Complete IRAC mapping of the CFHTLS-DEEP, MUSYC AND NMBS-II FIELDS
The IRAC mapping of the NMBS-II fields program is an imaging survey at 3.6
and 4.5m with the Spitzer Infrared Array Camera (IRAC). The observations
cover three Canada-France-Hawaii Telescope Legacy Survey Deep (CFHTLS-D)
fields, including one also imaged by AEGIS, and two MUSYC fields. These are
then combined with archival data from all previous programs into deep mosaics.
The resulting imaging covers a combined area of about 3 , with at least
2 hr integration time for each field. In this work, we present our data
reduction techniques and document the resulting coverage maps at 3.6 and
4.5m. All of the images are W-registered to the reference image, which is
either the z-band stack image of the 25\% best seeing images from the CFHTLS-D
for CFHTLS-D1, CFHTLS-D3, and CFHTLS-D4, or the K-band images obtained at the
Blanco 4-m telescope at CTIO for MUSYC1030 and MUSYC1255. We make all images
and coverage maps described herein publicly available via the Spitzer Science
Center.Comment: Accepted in PASP; released IRAC mosaics available upon publication of
the pape
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Monitoring Genetic and Metabolic Potential for In-Situ Bioremediation: Mass Spectrometry
A number of DOE sites are contaminated with dense non-aqueous phase liquids (DNAPLs) such as carbon tetrachloride and trichloroethylene. At many of these sites, microbial bioremediation is an attractive strategy for cleanup, since it has the potential to degrade DNAPLs in situ. A rapid screening method to determine the broad range potential of a site's microbial population for contaminant degradation would greatly facilitate assessment for in situ bioremediation, as well as for monitoring ongoing bioremediation treatment. Current laboratory-based treatability methods are cumbersome and expensive. In this project, we are developing methods based on matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) for rapid and accurate detection of polymerase chain reaction (PCR) products from microbial genes involved in biodegradation of pollutants. PCR primers are being developed to amplify DNA sequences that are amenable to MALDI-MS detection. This work will lay the foundation for development of a field-portable MS-based technique for rapid on site assessment and monitoring of bioremediation processes
<i>HST</i> F160W Imaging of Very Massive Galaxies at 1.5 < <i>z</i> < 3.0: Diversity of Structures and the Effect of Close Pairs on Number Density Estimates
We present a targeted follow-up Hubble Space Telescope WFC3 F160W imaging study of very massive galaxies (log(Mstar/Mâ)>11.2) selected from a combination of ground-based near-infrared galaxy surveys (UltraVISTA, NMBS-II, UKIDSS UDS) at 1.5zzz<3.0, however, we find evidence that quiescent galaxies are systematically larger than expected based on the extrapolation of the relation derived using lower stellar mass galaxies. We used the observed light profiles of the blended systems to decompose their stellar masses and investigate the effect of the close pairs on the measured number densities of very massive galaxies in the early universe. We estimate correction factors to account for close-pair blends and apply them to the observed stellar mass functions measured using ground-based surveys. Given the large uncertainties associated with this extreme population of galaxies, there is currently little tension between the (blending-corrected) number density estimates and predictions from theoretical models. Although we currently lack the statistics to robustly correct for close-pair blends, we show that this is a systematic effect which can reduce the observed number density of very massive galaxies by up to a factor of âŒ1.5, and should be accounted for in future studies of stellar mass functions
Telomere instability in the male germline
Telomeres play a key role in upholding the integrity of the genome, and telomerase expression in spermatogonial stem cells is responsible for the maintenance of telomere length in the human male germline. We have previously described extensive allelic variation in somatic cell telomere length that is set in the zygote, the ultimate source of which may be the germline. This implies that despite telomerase activity, substantial telomere length variation can be generated and tolerated in the germline; in order to investigate this further, we have examined the nature of telomere length variation in the human male germline. Here, we describe an analysis of both genome-wide telomere length and single molecule analysis of specific chromosome ends in human sperm. We observed individual specific differences in genome-wide telomere length. This variation may result from genetic differences within the components that determine the telomere length setting of each individual. Superimposed on the genome wide telomere length setting was a stochastic component of variation that generates germ-cells containing severely truncated telomeres. If not re-lengthened during early embryogenesis, such telomeres may limit the replicative capacity of cells derived from the zygote and have the potential to create fusagenic chromosomes, unbalanced translocations and terminal micro-deletions. These data may have implications for the genetic determination of ageing, genetic disease and fertility
N plus 2 Supersonic Concept Development and Systems Integration
Supersonic airplanes for two generations into the future (N+2, 2020-2025 EIS) were designed: the 100 passenger 765-072B, and the 30 passenger 765-076E. Both achieve a trans-Atlantic range of about 4000nm. The larger 765-072B meets fuel burn and emissions goals forecast for the 2025 time-frame, and the smaller 765-076E improves the boom and confidence in utilization that accompanies lower seat count. The boom level of both airplanes was reduced until balanced with performance. The final configuration product is two "realistic", non-proprietary future airplane designs, described in sufficient detail for subsequent multi-disciplinary design and optimization, with emphasis on the smaller 765-076E because of its lower boom characteristics. In addition IGES CAD files of the OML lofts of the two example configurations, a non-proprietary parametric engine model, and a first-cycle Finite Element Model are also provided for use in future multi-disciplinary analysis, optimization, and technology evaluation studies
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