4,840 research outputs found

    MSFC Skylab instrumentation and communication system mission evaluation

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    An evaluation of the in-orbit performance of the instrumentation and communications systems installed on Skylab is presented. Performance is compared with functional requirements and the fidelity of communications. In-orbit performance includes processing engineering, scientific, experiment, and biomedical data, implementing ground-generated commands, audio and video communication, generating rendezvous ranging information, and radio frequency transmission and reception. A history of the system evolution based on the functional requirements and a physical description of the launch configuration is included. The report affirms that the instrumentation and communication system satisfied all imposed requirements

    Submission to the Senate Select Committee on Administration of Sport Grants Should there be a $100 million federal community sport grants program at all?

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    It is questionable whether national funds designed to be allocated in small amounts paid directly to local community organisations have a part to play in a federal system. Apart from the clear temptation for pork-barrelling, they make no sense in terms of efficiency and rational policy, particularly when, as is the case with sport and recreation, there is already a system in place to assess local community needs

    Clinical Practice Guidelines on Ordering Echocardiography Before Hip Fracture Repair Perform Differently from One Another

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    Background: Osteoporotic hip fractures typically occur in frail elderly patients with multiple comorbidities, and repair of the fracture within 48 h is recommended. Pre-operative evaluation sometimes involves transthoracic echocardiography (TTE) to screen for heart disease that would alter peri-operative management, yet TTE can delay surgery and is resource intensive. Evidence suggests that the use of clinical practice guidelines (CPGs) can improve care. It is unclear which guidelines are most useful in hip fracture patients. Questions/Purposes: We sought to evaluate the performance of the five commonly used CPGs in determining which patients with acute fragility hip fracture require TTE and to identify common features among high-performing CPGs that could be incorporated into care pathways. Patients and Methods: We performed a retrospective study of medical records taken from an institutional database of osteoporotic hip fracture patients to identify those who underwent pre-operative TTE. History and physical examination findings were recorded; listed indications for TTE were compared against those given in five commonly used CPGs: those from the American College of Cardiology/American Heart Association (ACC/AHA), the British Society of Echocardiography (BSE), the European Society of Cardiology and the European Society of Anaesthesiology(ESC/ESA), the Association of Anaesthetists of Great Britain and Ireland (AAGBI), and the Scottish Intercollegiate Guidelines Network (SIGN). We then calculated the performance (sensitivity and specificity) of the CPGs in identifying patients with TTE results that had the potential to change peri-operative management. Results: We identified 100 patients who underwent pre-operative TTE. Among those, the patients met criteria for TTE 32 to 66% of the time, depending on the CPG used. In 14% of those receiving TTE, the test revealed new information with the potential to change management. The sensitivity of the CPGs ranged from 71% (ESC/ESA and AAGBI) to 100% (ACC/AHA and SIGN). The CPGs\u27 specificity ranged from 37% (BSE) to 74% (ESC/ESA). The more sensitive guidelines focused on a change in clinical status in patients with known disease or clinical concern regarding new-onset disease. Conclusions: In patients requiring fixation of osteoporotic hip fractures, TTE can be useful for identifying pathologies that could directly change peri-operative management. Our data suggest that established CPGs can be safely used to identify which patients should undergo pre-operative TTE with low risk of missed pathology

    Interactive Effects of Time, CO\u3csub\u3e2\u3c/sub\u3e, N, and Diversity on Total Belowground Carbon Allocation and Ecosystem Carbon Storage in a Grassland Community

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    Predicting if ecosystems will mitigate or exacerbate rising CO2 requires understanding how elevated CO2 will interact with coincident changes in diversity and nitrogen (N) availability to affect ecosystem carbon (C) storage. Yet achieving such understanding has been hampered by the difficulty of quantifying belowground C pools and fluxes. Thus, we used mass balance calculations to quantify the effects of diversity, CO2, and N on both the total amount of C allocated belowground by plants (total belowground C allocation, TBCA) and ecosystem C storage in a periodically burned, 8-year Minnesota grassland biodiversity, CO2, and N experiment (BioCON). Annual TBCA increased in response to elevated CO2, enriched N, and increasing diversity. TBCA was positively related to standing root biomass. After removing the influence of root biomass, the effect of elevated CO2 remained positive, suggesting additional drivers of TBCA apart from those that maintain high root biomass. Removing root biomass effects resulted in the effects of N and diversity becoming neutral or negative (depending on year), suggesting that the positive effects of diversity and N on TBCA were related to treatmentdriven differences in root biomass. Greater litter production in high diversity, elevated CO2, and enhanced N treatments increased annual ecosystem C loss in fire years and C gain in non-fire years, resulting in overall neutral C storage rates. Our results suggest that frequently burned grasslands are unlikely to exhibit enhanced C sequestration with increasing atmospheric CO2 levels or N deposition
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