1,292 research outputs found
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Improving Sea-Surface Remote Sensing of Ocean Wind Vectors by Scatterometers
Though scatterometers have been used to sense global ocean surface wind vectors for over 40 years, there remain some significant shortcomings. The largest problems appear in retrieving the wind vector when the ocean is being driven by high wind speeds or when rain is present in the beam-illuminated volume. Geophysical model functions (GMFs) developed using data from high-wind events can improve retrievals at high wind speeds, but only if sufficient ground truth measurements exist in the scatterometer swath. Airborne scatterometers, such as the Imaging Wind and Rain Airborne Profiler (IWRAP) developed by the Microwave Remote Sensing Laboratory (MIRSL) at the University of Massachusetts Amherst (UMass), are well-suited for collecting such high-wind data, largely due to their abilities to reposition to areas of interest, sample the ocean surface on a small scale, and use complementary in-situ sensors. The IWRAP system is also able to investigate the effect of precipitation impact (the âsplash effectâ) on the sea surface normalized radar cross-section (NRCS), since it can discriminate between volume and surface effects of precipitation. This dissertation will improve upon the existing IWRAP GMF and quantify the effect of precipitation on wind vector retrievals. Additionally, IWRAP is used to observe the effects of Earth-incidence angle and polarization on the sea-surface radar backscatter, helping scatterometer GMFs to be applicable to other satellite sensors. IWRAP and collocated Stepped Frequency Microwave Radiometer (SFMR) data were gathered from 4 years of flight experiments. Using this data, the high-wind IWRAP GMF is extended to incidence angles near 22° at C- and Ku-band VV- and HH-polarization from 15 m sâ1 to 45 m sâ1. There is also a revision made to the higher harmonics of the GMF near 50° incidence, but the mean NRCS appears to be modeled appropriately. There is no splash effect observed in the mean NRCS or first harmonic at wind speeds from 15 m sâ1 to 45 m sâ1. The second harmonic shows some muted behavior in precipitation. Lastly, a wind speed dependence is observed in the VV/HH NRCS polarization ratio in both incidence angle and azimuth
Higher Education Leadership Development During the COVID-19 Pandemic: An Exploration of Online Learner Readiness
The COVID-19 pandemic precipitated profound disruptions across the higher education sector as institutions were forced to restructure entire systems and operate with significantly reduced resources. Most notably, many institutions were forced to transition to fully virtual instruction. The present study examined adult leadership development program participantsâ perceptions of online learning readiness during the transition to a fully virtual training environment precipitated by the COVID-19 pandemic. A census of the 2020 LEAD21 class was taken, and perceptions of online learning readiness were collected via a retrospective pre- and post-test. Descriptive and inferential statistics were used. Respondents had the highest levels of agreement with computer and Internet self-efficacy and the lowest levels of agreement with learner control in an online context. A paired t-test was conducted to analyze the difference in perceptions of online learning readiness post-training and retrospective pre-training. A statistically significant increase was observed for overall online learning readiness, as well as for computer and Internet self-efficacy, learner control, motivation for learning, Internet communication self-efficacy, and self-directed learning. An implication from this finding is that the transition to fully virtual training resulted in increased online learning readiness across all dimensions. With new strains of COVID-19 emerging and the potential for ongoing restrictions for social interaction, online learning will continue to be an important aspect of the educational process. It is vital that higher education leaders consider individualsâ readiness to effectively engage in online training and instruction. Implications and recommendations for future research in practice in international contexts are provided
Experiment K-6-16. Morphological examination of rat testes. The effect of Cosmos 1887 flight on spermatogonial population and testosterone level in rat testes
Testes from rats flown on Cosmos 1887 for twelve and a half days were compared to basal control, synchronous control and vivarium maintained rats. When the mean weights of flight testes, normalized for weight/100 gms, were compared to the vivarium controls they were 6.7 percent lighter. Although the flight testes were lighter than the synchronous, the difference is not significant. Counts of spermatogonial cells from 5 animals in each group revealed a 4 percent decrease in flight compared to vivarium controls. In both cases the t-Test significance was less than 0.02. The serum testosterone levels of all animals (flight, synchronous and vivarium) were significantly below the basal controls
Prospectus, April 14, 1982
JACOB SPEAKS AT RAMADA INN FRIDAY: LEADER WORKS FOR RACIAL EQUALITY; News Digest; Students speak at meeting; Achievement winners announced; Senator voices opinion on issues; Students should help StuGo out with input; WPCD not real issue -- fear of change is the problem; Foreign film festival offered next week; P.C. Happenings...: Circle K thanks jellybean guessers, Learn to manage time, Phi Beta Lambda thanks helpful people, Program focuses on wellness, Swing Choir places first, P.C. sponsors management workshop, Thanks to all who helped in blood drive, Parkland plans for Ground Zero Week, Swing Choir to perform today, Rathskeller to play 1st outdoor concert; Phi Beta Lambda: bettering business; Students to meet to help ratify ERA amendment; Positive attitude important in job hunting, interview; Motorcycle trips are a great way to go; Alcoholics find needed help at AA; Bicycle tour scheduled; Respiratory therapy offers many career opportunities; Community Calendar; Classifieds; Theatre production performances scheduled; This movie is a four-way winner; What\u27s been happening in the music world?; Weather keeps team prisoner; Men\u27s baseball 12-game statistics; StuGo answers questions about new widescreen TV; Cancelled practices may hurt team play; Sports Watch...https://spark.parkland.edu/prospectus_1982/1022/thumbnail.jp
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Glucose transporter 3 is a rab11-dependent trafficking cargo and its transport to the cell surface is reduced in neurons of CAG140 Huntingtonâs disease mice
Huntingtonâs disease (HD) disturbs glucose metabolism in the brain by poorly understood mechanisms. HD neurons have defective glucose uptake, which is attenuated upon enhancing rab11 activity. Rab11 regulates numerous receptors and transporters trafficking onto cell surfaces; its diminished activity in HD cells affects the recycling of transferrin receptor and neuronal glutamate/cysteine transporter EAAC1. Glucose transporter 3 (Glut3) handles most glucose uptake in neurons. Here we investigated rab11 involvement in Glut3 trafficking. Glut3 was localized to rab11 positive puncta in primary neurons and immortalized striatal cells by immunofluorescence labeling and detected in rab11-enriched endosomes immuno-isolated from mouse brain by Western blot. Expression of dominant active and negative rab11 mutants in clonal striatal cells altered the levels of cell surface Glut3 suggesting a regulation by rab11. About 4% of total Glut3 occurred at the cell surface of primary WT neurons. HD140Q/140Q neurons had significantly less cell surface Glut3 than did WT neurons. Western blot analysis revealed comparable levels of Glut3 in the striatum and cortex of WT and HD140Q/140Q mice. However, brain slices immunolabeled with an antibody recognizing an extracellular epitope to Glut3 showed reduced surface expression of Glut3 in the striatum and cortex of HD140Q/140Q mice compared to that of WT mice. Surface labeling of GABAα1 receptor, which is not dependent on rab11, was not different between WT and HD140Q/140Q mouse brain slices. These data define Glut3 to be a rab11-dependent trafficking cargo and suggest that impaired Glut3 trafficking arising from rab11 dysfunction underlies the glucose hypometabolism observed in HD
Changes in Circulating Angiogenic Cell Number and Function During and After an Ultramarathon
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Surgical treatment of prosthetic valve endocarditis
AbstractFrom 1975 through 1992, we reoperated on 146 patients for the treatment of prosthetic valve endocarditis. Prosthetic valve endocarditis was considered to be early (<1 year after operation) in 46 cases and active in 103 cases. The extent of the infection was prosthesis only in 66 patients, anulus in 46, and cardiac invasion in 34. Surgical techniques evolved in the direction of increasingly radical débridement of infected tissue and reconstruction with biologic materials. All patients were treated with prolonged postoperative antibiotic therapy. There were 19 (13%) in-hospital deaths. Univariate analyses demonstrated trends toward increasing risk for patients with active endocarditis and extension of infection beyond the prosthesis; however, the only variables with a significant (p < 0.05) association with increased in-hospital mortality confirmed with multivariate testing were impaired left ventricular function, preoperative heart block, coronary artery disease, and culture of organisms from the surgical specimen. During the study period, mortality decreased from 20% (1975 to 1984) to 10% (1984 to 1992). For hospital survivors the mean length of stay was 25 days. Follow-up (mean interval 62 months) documented a late survival of 82% at 5 postoperative years and 60% at 10 years. Older age was the only factor associated (p = 0.006) with late death. Nineteen patients needed at least one further operation; reoperation-free survival was 75% at 5 and 50% at 10 postoperative years. Fever in the immediate preoperative period was the only factor associated with decreased late reoperation-free survival (p = 0.032). Prosthetic valve endocarditis remains a serious complication of valve replacement, but the in-hospital mortality of reoperations for prosthetic valve endocarditis has declined. With extensive débridement of infected tissue and postoperative antibiotic therapy, the extent and activity of prosthetic valve endocarditis does not appear to have a major impact on late outcome, and the majority of patients with this complication survive for 10 years after the operation. (J THORAC CARDIOVASC SURG 1996;111:198-210
The Effect of High Energy (HZE) Particle Radiation (40Ar) on Aging Parameters of Mouse Hippocampus and Retina
Eight month old C57BL6 mice were exposed (head only) to 0.5 rad or 50 rads of Argon particles at the Lawrence Berkeley Radiation Facility, CA. Neuromotor performance was assessed monthly for six months beginning twelve weeks post-irradiation using a \u27\u27string test . The decline in motor performance was dose-related and none of the animals was able to complete the task after four months of testing. Morphological changes were monitored six and twelve months post-irradiation by light and electron microscopy. The synaptic density in the CA-1 area of the hippocampus decreased six and twelve months after irradiation. The decrease after twelve months was less than after six months. The width of the outer nuclear layer (ONL) of the retina increased with increasing dose. The number of blood vessels between the ONL and the ganglion layer decreased twelve months after irradiation and this area did not show significant accumulation of age pigment
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