8,319 research outputs found

    Investigation of the visual reference requirements for pilot control of gliding parachutes for land landing of spacecraft

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    Test program for determining visual reference requirements for pilot control of gliding parachutes used in landing spacecraft on lan

    An Evaluation of Virginia Gold: A Medicaid Program to Improve Nursing Facility Quality of Care

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    A qualitative case study design employing focus groups was used to evaluate certified nursing assistant (CNA) (n = 26) and resident (n = 30) perceptions of the Virginia Gold Quality Improvement Program, a Medicaid funded 2-year quality improvement intervention piloted in five nursing facilities. As part of the program, the nursing facilities implemented quality improvement projects to develop supportive work environments in an effort to reduce CNA turnover and improve quality of care. Overall, the focus group participants viewed Virginia Gold positively and reported that CNA turnover decreased, while care quality improved during the program. These findings are supported by a previous Virginia Gold evaluation as well as by the results from a quantitative analysis of nursing facility CNA turnover and quality of care data and interviews with selected nursing facility management staff (n = 7) 1-year following the program’s culmination. A key finding from the management interviews is that the quality improvement projects became self-sustaining over time allowing all five nursing facilities to continue the projects without state funding

    Brain Trust: Students for Students: VCU to RPS Mentorship Program

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    As a public, urban research institution, Virginia Commonwealth University embraces the importance of developing university-community partnerships that generate innovative solutions to societal challenges and prepare engaged citizens of tomorrow. The Students for Students: VCU to RPS Mentorship Program provides a model that will connect current VCU students to current Richmond Public Schools (RPS) students through a formal, multi-year mentorship. The ultimate goal of this program is to support and positively influence RPS students, while providing current VCU students with an opportunity to give back to the community while developing their mentorship skills. The mentoring relationship will seek to motivate RPS sophomores, juniors and seniors to improve school performance, graduate on time, and craft a post-high school path

    The Oklahoma Congress of Parents and Teachers, 1922 to 1957 /

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    SARS-CoV replication and pathogenesis in an in vitro model of the human conducting airway epithelium

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    SARS coronavirus (SARS-CoV) emerged in 2002 as an important cause of severe lower respiratory tract infection in humans and in vitro models of the lung are needed to elucidate cellular targets and the consequences of viral infection. The severe and sudden onset of symptoms, resulting in an atypical pneumonia with dry cough and persistent high fever in cases of severe acute respiratory virus brought to light the importance of coronaviruses as potentially lethal human pathogens and the identification of several zoonotic reservoirs has made the reemergence of new strains and future epidemics all the more possible. In this chapter, we describe the pathology of SARS-CoV infection in humans and explore the use of two models of the human conducting airway to develop a better understanding of the replication and pathogenesis of SARS-CoV in relevant in vitro systems. The first culture model is a human bronchial epithelial cell line Calu3 that can be inoculated by viruses either as a non-polarized monolayer of cells or polarized cells with tight junctions and microvilli. The second model system, derived from primary cells isolated from human airway epithelium and grown on Transwells, form a pseudostratified mucociliary epithelium that recapitulates the morphological and physiological features of the human conducting airway in vivo. Experimental results using these lung epithelial cell models demonstrate that in contrast to the pathology reported in late stage cases SARS-CoV replicates to high titers in epithelial cells of the conducting airway. The SARS-CoV receptor, human angiotensin 1 converting enzyme 2 (hACE2), was detected exclusively on the apical surface of cells in polarized Calu3 cells and human airway epithelial cultures (HAE), indicating that hACE2 was accessible by SARS-CoV after airway lumenal delivery. Furthermore, in HAE, hACE2 was exclusively localized to ciliated airway epithelial cells. In support of the hACE2 localization data, the most productive route of inoculation and progeny virion egress in both polarized Calu3 and ciliated cells of HAE was the apical surface suggesting mechanisms to release large quantities of virus into the lumen of the human lung. Preincubation of the apical surface of cultures with antisera directed against hACE2 reduced viral titers by 2 logs while antisera against DC-SIGN/DC-SIGNR did not reduce viral replication levels suggesting that hACE2 is the primary receptor for entry of SARS-CoV into the ciliated cells of HAE cultures. To assess infectivity in ciliated airway cultures derived from susceptible animal species we generated a recombinant SARS-CoV by deletion of open reading frame 7a/7b (ORF 7a/b) and insertion of the green fluorescent protein (GFP) resulting in SARS-CoV GFP. SARS-CoV GFP replicated to similar titers as wild type viruses in Vero E6, MA104, and CaCo2 cells. In addition, SARS-CoV replication in airway epithelial cultures generated from Golden Syrian hamster tracheas reached similar titers to the human cultures by 72 hours post infection. Efficient SARS-CoV infection of ciliated cell-types in HAE provides a useful in vitro model of human lung origin to study characteristics of SARS-CoV replication and pathogenesis

    On the origin of enstatite chondrite chondrules based on their petrography and comparison with experimentally produced chondrules

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    The recent discovery of several types 3 and 4 enstatite chondrites (EC) in the Antarctic collection increases greatly the ability to compare unaltered, naturally-formed EC chondrules with chondrules produced experimentally from melts of enstatitic chondrule composition. Because these discoveries are so recent we have undertaken the task of characterizing these chondrules for purposes of comparison. We have looked at several new Antarctic E3 chondrites and Qingzhen. They all have numerous chondrules with well defined outlines and readily identifiable textures. All have mostly porphyritic chondrules, but there are differences in the size and kinds of textures. Radial pyroxene, barred/dendritic px, and cryptocrystalline chondrules are present in differing amounts with one exception

    The effects of climatic fluctuations and extreme events on running water ecosystems

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    Most research on the effects of environmental change in freshwaters has focused on incremental changes in average conditions, rather than fluctuations or extreme events such as heatwaves, cold snaps, droughts, floods or wildfires, which may have even more profound consequences. Such events are commonly predicted to increase in frequency, intensity and duration with global climate change, with many systems being exposed to conditions with no recent historical precedent. We propose a mechanistic framework for predicting potential impacts of environmental fluctuations on running water ecosystems by scaling up effects of fluctuations from individuals to entire ecosystems. This framework requires integration of four key components: effects of the environment on individual metabolism, metabolic and biomechanical constraints on fluctuating species interactions, assembly dynamics of local food webs and mapping the dynamics of the meta-community onto ecosystem function. We illustrate the framework by developing a mathematical model of environmental fluctuations on dynamically assembling food webs. We highlight (currently limited) empirical evidence for emerging insights and theoretical predictions. For example, widely supported predictions about the effects of environmental fluctuations are: high vulnerability of species with high per capita metabolic demands such as large-bodied ones at the top of food webs; simplification of food web network structure and impaired energetic transfer efficiency; reduced resilience and top-down relative to bottom-up regulation of food web and ecosystem processes. We conclude by identifying key questions and challenges that need to be addressed to develop more accurate and predictive bio-assessments of the effects of fluctuations, and implications of fluctuations for management practices in an increasingly uncertain world

    Effect of thoracic venting on arterial pressure, and flow during external cardiopulmonary resuscitation in animals

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    To test the hypothesis that fluctuations in global intrathoracic pressure are the dominant cause of blood flow during external cardiopulmonary resuscitation (CPR) the authors studied the effects of open pneumothorax on experimental CPR in 7 domestic pigs and 12 mongrel dogs. Similar studies were conducted independently at three laboratories and are reported jointly. All studies were conducted during electrically induced ventricular fibrillation and with standard CPR technique, including ventral-dorsal chest compression at 60/min, 0.5 sec compression duration, 1:5ventilation:compression ratio. During alternate periods of CPR, intrathoracic pressure was vented through bilateral chest tubes, placed to create open pneumothorax and partial collapse of the lungs. During this maneuver, global intrathoracic pressure fluctuations were greatly attenuated, but direct but direct cardiac compression and adequate ventilation continued. In the three laboratories, systolic/diastolic arterial pressures during CPR with thoracic venting (± SE) averaged 68 ± 4.2/28 ± 3.3, 60 ± 10/18 ± 4.5, and 66 ± 6.3/23 ± 1.5 mm Hg. These values are compared to 68 ± 4.4/27 ± 3.0, 67 ± 12/17 ± 6.1, and 56± 6.2/22 ± 1.9 mm Hg with the thorax intact. Carotid artery mean flow, measured with an in-line flowmeter, was 13.0 ± 2.2 ml/min vented vs. 13.4 ± 2.6 intact in 7 pigs; 11.4 ± 3.8 ml/min vented vs. 11.2 ± 3.7 intact in 5 dogs. Cardiac output, determined by indicator dilution, was 25 ± 4.3 ml/min/kg vented vs. 20 ± 4.3 intact in 7 dogs. Thoracic venting did not decrease blood pressures and flows during CPR, as would be predicted from the hypothesis that generalized intrathoracic pressure fluctuations are the dominant hemodynamic mechanism. The results are consistent with the classical notion that CPR works by compression of the heart between the sternum and the spine. This mechanism should not be discounted in future attempts to improve CPR
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