144 research outputs found
PLIF Imaging of Capsule RCS Jets, Shear Layers, and Simulated Forebody Ablation
Planar laser-induced fluorescence (PLIF) has been used to investigate hypersonic flows associated with capsule reentry vehicles. These flows included reaction control system (RCS) jets, shear layer flow, and simulated forebody heatshield ablation. Pitch, roll, and yaw RCS jets were studied. PLIF obtained planar slices in these flowfields. These slices could be viewed individually or they could be combined using computer visualization techniques to reconstruct the three dimensional shape of the flow. The tests described herein were conducted in the 31-Inch Mach 10 Air Tunnel at NASA Langley Research Center. Improvements to many facets of the imaging system increased the efficiency and quality of both data acquisition, in addition to increasing the overall robustness of the system
Numerical Simulations of Globular Cluster Formation
We examine various physical processes associated with the formation of
globular clusters by using the three-dimensional Smoothed Particle
Hydrodynamics (SPH) code. Our code includes radiative cooling of gases, star
formation, energy feedback from stars including stellar winds and supernovae,
and chemical enrichment by stars. We assume that, in the collapsing galaxy,
isothermal cold clouds form through thermal condensations and become
proto-globular clouds. We calculate the size of proto-globular clouds by
solving the linearized equations for perturbation. We compute the evolution of
the inner region of the proto-cloud with our SPH code for various initial
radius and initial composition of gases. When the initial gases contain no
heavy elements, the evolution of proto-clouds sensitively depends on the
initial radius. For a smaller initial radius, the initial star burst is so
intense that the subsequent star formation occurs in the central regions to
form a dense star cluster as massive as the globular cluster. When the initial
gases contain some heavy elements, the metallicity of gases affects the
evolution and the final stellar mass. If the initial radius of the
proto-globular clouds was relatively large, the formation of a star cluster as
massive as the globular clusters requires the initial metallicity as high as
[Fe/H] . The self-enrichment of heavy elements in the star cluster
does not occur in all cases.Comment: Accpeted for publication in the ApJ. Correctiong errors in Table
of the Canola Oil Multicenter Intervention Trial (COMIT)
Plasma fatty acid changes following consumption of dietary oils containing n-3, n-6, and n-9 fatty acids at different proportions: preliminary finding
Recommended from our members
Aspiration therapy for the treatment of obesity: 4-year results of a multicenter randomized controlled trial.
BackgroundThe AspireAssist is the first Food and Drug Administration-approved endoluminal device indicated for treatment of class II and III obesity.ObjectivesWe earlier reported 1-year results of the PATHWAY study. Here, we report 4-year outcomes.SettingUnited States-based, 10-center, randomized controlled trial involving 171 participants with the treatment arm receiving Aspiration Therapy (AT) plus Lifestyle Therapy and the control arm receiving Lifestyle Therapy (2:1 randomization).MethodsAT participants were permitted to continue in the study for an additional year up to a maximum of 5 years providing they maintained at least 10% total weight loss (TWL) from baseline at each year end. For AT participants who continued the study, 5 medical monitoring visits were provided at weeks 60, 68, 76, 90, and 104 and thereafter once every 13 weeks up to week 260. Exclusion criteria were a history of eating disorder or evidence of eating disorder on a validated questionnaire. Follow-up weight, quality of life, and co-morbidities were compared with the baseline levels. In addition, rates of serious adverse event, persistent fistula, withdrawal, and A-tube replacement were reported. All analyses were performed using a per-protocol analysis.ResultsOf the 82 AT participants who completed 1 year, 58 continued to this phase of the trial. Mean baseline body mass index of these 58 patients was 41.6 Ā± 4.5 kg/m2. At the end of first year (at the beginning of the follow-up study), these 58 patients had a body mass index of 34.1 Ā± 5.4 kg/m2 and had achieved an 18.3 Ā± 8.0% TWL. On a per protocol basis, patients experienced 14.2%, 15.3%, 16.6%, and 18.7% TWL at 1, 2, 3, and 4 years, respectively (P < .01 for all). Forty of 58 patients (69%) achieved at least 10% TWL at 4 years or at time of study withdrawal. Improvements in quality of life scores and select cardiometabolic parameters were also maintained through 4 years. There were 2 serious adverse events reported in the second through fourth years, both of which resolved with removal or replacement of the A tube. Two persistent fistulas required surgical repair, representing approximately 2% of all tube removals. There were no clinically significant metabolic or electrolytes disorders observed, nor any evidence for development of any eating disorders.ConclusionsThe results of this midterm study have shown that AT is a safe, effective, and durable weight loss alternative for people with class II and III obesity and who are willing to commit to using the therapy and adhere to adjustments in eating behavior
Metal-poor Field Blue Stragglers: More Evidence for Mass Transfer
We report radial velocity studies of five candidate metal-poor field blue
stragglers, all known to be deficient in lithium. Four of the five stars are
single-lined spectroscopic binaries, with periods ranging from 302 to 840 days,
and low orbital eccentricities, in agreement with similar behavior found for
other blue straggler candidates by Preston & Sneden (2000) and Carney et al.
(2001). The limited data available for lithium abundances indicate that all
blue straggler candidates have depleted lithium abundances. Our results show
higher values of v(rot) sin i for the binary stars than comparable temperature
constant-velocity stars. The orbital periods are too long for tidal effects to
now be important, implying that spin-up during mass transfer when the orbital
separations and periods were smaller is that cause of the enhanced rotation.Comment: To appear in Astronomical Journal (January 2005 issue
An enhanced model for digital reference services
Digital Reference Service (DRS) play a vital role in the Digital Library (DL) research.
DRS is a very valuable service provided by DL. Unfortunately, the reference service
movement towards digital environment begins late, and this shift was not model
based. So, a journey towards a digital environment without following a proper model
raises some issues. A few researchers presented a general process model (GPM) in
the late 1990s, but this process model could not overcome the problems of DRS. This
paper proposes an enhanced model for DRS that use the storage and re-use
mechanism with other vital components like DRS search engine and ready reference
for solving the issues in DRS. Initially, storage and re-use mechanism are designed
and finally, DRS search engine is designed to search appropriate answers in the
knowledge base. We improved the GPM by incorporating the new components. The
simulation results clearly states that the proposed model increased the service
efficiency by reducing the response time from days to seconds for repeated questions
and decreased the workload of librarian
Consensus Statement on Concussion in SportĆ¢ The 4th International Conference on Concussion in Sport Held in Zurich, November 2012
Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/147044/1/pmr2255.pd
Consensus statement on concussion in sportāthe 5 th international conference on concussion in sport held in Berlin, October 2016
The 2017 Concussion in Sport Group (CISG) consensus statement is designed to build on the principles outlined in the previous statements1ā4 and to develop further conceptual understanding of sport-related concussion (SRC) using an expert consensus-based approach. This document is developed for physicians and healthcare providers who are involved in athlete care, whether at a recreational, elite or professional level. While agreement exists on the principal messages conveyed by this document, the authors acknowledge that the science of SRC is evolving and therefore individual management and return-to-play decisions remain in the realm of clinical judgement. This consensus document reflects the current state of knowledge and will need to be modified as new knowledge develops. It provides an overview of issues that may be of importance to healthcare providers involved in the management of SRC. This paper should be read in conjunction with the systematic reviews and methodology paper that accompany it. First and foremost, this document is intended to guide clinical practice; however, the authors feel that it can also help form the agenda for future research relevant to SRC by identifying knowledge gaps
Impaired neural development in a zebrafish model for Lowe syndrome
Lowe syndrome, which is characterized by defects in the central nervous system, eyes and kidneys, is caused by mutation of the phosphoinositide 5-phosphatase OCRL1. The mechanisms by which loss of OCRL1 leads to the phenotypic manifestations of Lowe syndrome are currently unclear, in part, owing to the lack of an animal model that recapitulates the disease phenotype. Here, we describe a zebrafish model for Lowe syndrome using stable and transient suppression of OCRL1 expression. Deficiency of OCRL1, which is enriched in the brain, leads to neurological defects similar to those reported in Lowe syndrome patients, namely increased susceptibility to heat-induced seizures and cystic brain lesions. In OCRL1-deficient embryos, Akt signalling is reduced and there is both increased apoptosis and reduced proliferation, most strikingly in the neural tissue. Rescue experiments indicate that catalytic activity and binding to the vesicle coat protein clathrin are essential for OCRL1 function in these processes. Our results indicate a novel role for OCRL1 in neural development, and support a model whereby dysregulation of phosphoinositide metabolism and clathrin-mediated membrane traffic leads to the neurological symptoms of Lowe syndrome
The impact of laxative use upon symptoms in patients with proven slow transit constipation
<p>Abstract</p> <p>Background</p> <p>Constipation severity is often defined by symptoms including feelings of complete evacuation, straining, stool frequency and consistency. These descriptors are mostly obtained in the absence of laxative use. For many constipated patients laxative usage is ubiquitous and long standing. Our aim was to determine the impact of laxative use upon the stereotypic constipation descriptors.</p> <p>Methods</p> <p>Patients with confirmed slow transit constipation completed 3-week stool diaries, detailing stool frequency and form, straining, laxative use and pain and bloating scores. Each diary day was classified as being under laxative affect (laxative affected days) or not (laxative unaffected days). Unconditional logistic regression was used to assess the affects of laxatives on constipation symptoms.</p> <p>Results</p> <p>Ninety four patients with scintigraphically confirmed slow transit constipation were enrolled in the study. These patients reported a stool frequency of 5.6 Ā± 4.3 bowel motions/week, only 21 patients reported <3 bowel motions/week. Similarly, 21 patients reported a predominant hard stool at defecation. The majority (90%) of patients reported regular straining. A regular feeling of complete evacuation was reported in just 7 patients. Daily pain and/or bloating were reported by 92% of patients. When compared with laxative unaffected days, on the laxative affected days patients had a higher stool frequency (OR 2.23; <it>P </it><0.001) and were more likely to report loose stools (OR 1.64; <it>P </it><0.009). Laxatives did not increase the number of bowel actions associated with a feeling of complete evacuation. Laxative use had no affect upon straining, pain or bloating scores</p> <p>Conclusions</p> <p>The reporting of frequent and loose stools with abdominal pain and/or bloating is common in patients with slow transit constipation. While laxative use is a significant contributor to altering stool frequency and form, laxatives have no apparent affect on pain or bloating or upon a patients feeling of complete evacuation. These factors need to be taken into account when using constipation symptoms to define this population.</p
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