316 research outputs found

    Results of a 0.03- scale aerodynamic characteristics investigation of Boeing 747 carrier (model no. AX 1319 I-1) mated with a space shuttle orbiter (model 45-0) conducted in the Boeing transonic wind tunnel (CA5), volume 1

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    The performance, stability, and control characteristics of various carrier aircraft configurations are presented. Aerodynamic characteristics of the carrier mated with the Orbiter, carrier alone, and Orbiter alone were investigated. Carrier support system tare and interference effects were determined. Six-component force and moment data were recorded for the carrier and Orbiter. Buffet onset characteristics of the carrier vertical tail and horizontal tail were recorded. Angles of attack from -3 deg through 26 deg and angles of slideslip between +12 deg and -12 deg were investigated at Mach numbers from 0.15 through 0.70. Photographs are included

    Correlation but no causation between leaf nitrogen and maximum assimilation: the role of drought and reproduction in gas exchange in an understory tropical plant Miconia ciliata (Melastomataceae).

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    Alternative hypotheses were tested to explain a previously reported anomaly in the response of leaf photosynthetic capacity at light saturation (A..) in Miconia ciliata to dry-season irrigation. The anomaly is characterized by an abrupt increase in leaf A._ for nonirrigated plants at the onset of the rainy season to values that significantly exceeded corresponding measurements for plants that were irrigated during the previous dry season. Hypothesis I posits that a pulse in leaf nitrogen increases CO2 assimilation in nonirrigated plants at the onset of the wet season and is dampened for irrigated plants; this hypothesis was rejected because, although a wet-season nitrogen pulse did occur, it was identical for both irrigated and nonirrigated plants and was preceded by the increase in assimilation by nonirrigated plants. Hypothesis 2 posits that a reproduction-related, compensatory photosynthetic response occurs in nonirrigated plants following the onset of the wet season and is dampened in irrigated plants; consistent with hypothesis 2, high maximum assimilation rates for control plants in the wet season were significantly correlated with fruiting and flowering, whereas irrigation caused flowering and fruiting in the dry season, spreading M. ciliata reproductive activity in irrigated plants across the entire year

    Stroke-Induced Respiratory Dysfunction Is Associated With Cognitive Decline

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    BACKGROUND: Respiratory dysfunction is a common complication of stroke, with an incidence of over 60%. Despite the high prevalence of stroke-induced respiratory dysfunction, how disordered breathing influences recovery and cognitive outcomes after ischemic stroke is unknown. We hypothesized that stroke induces chronic respiratory dysfunction, breathing instability, and apnea in mice, which would contribute to higher mortality and greater poststroke cognitive deficits. METHODS: Mice were subjected to a 60-minute transient middle cerebral artery occlusion or permanent distal middle cerebral artery occlusion. Whole body plethysmography was performed on C57BL/6 young (2-3 months) and aged (20 months) male and female mice. Animals were exposed to a variety of gas conditions to assess the contribution of peripheral and central chemoreceptors. A battery of cognitive tests was performed to examine behavioral function. RESULTS: Middle cerebral artery occlusion led to disordered breathing characterized by hypoventilation and apneas. Cognitive decline correlated with the severity of disordered breathing. Distal permanent middle cerebral artery occlusion, which produces a smaller cortical infarct, also produced breathing disorders and cognitive impairment but only in aged mice. CONCLUSIONS: Our data suggest that poststroke apnea is associated with cognitive decline and highlights the influence of aging on breathing disorders after stroke. Therefore, the treatment of respiratory instability may be a viable approach to improving cognitive outcomes after stroke

    The Trail, 1965-02-26

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    https://soundideas.pugetsound.edu/thetrail_all/1903/thumbnail.jp

    Postextubation pulmonary edema: A case series and review

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    SummaryWe report a series of patients with postextubation pulmonary edema who had no obvious risk factors for the development of this syndrome.MethodsPatients identified by the pulmonary consultation service at an academic medical center were reviewed.ResultsFourteen cases were collected and analyzed. The average age was 34.5 years; 12 patients were male. The average BMI was 25.5. None had documented previous lung disease. Most operations were scheduled as outpatient procedures, and the type of surgery ranged from an incision and drainage of a bite wound to an open reduction- internal fixation of the radius. None of the patients had upper airway surgery. The length of surgeries ranged from 27 to 335min. Laryngospasm was the most commonly identified obstructing event postextubation. Treatment involved airway support when needed, supplemental oxygen, and diuretics.ConclusionsIt would appear that all patients, especially young men, are at risk for the development of this syndrome and that the pathogenesis remains uncertain in many cases
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