717 research outputs found
Program for establishing long-time flight service performance of composite materials in the center wing structure of C-130 aircraft. Phase 5: Flight service and inspection
Inspections of the C-130 composite-reinforced center wings were conducted over the flight service monitoring period of more than six years. Twelve inspections were conducted on each of the two C-130H airplanes having composite reinforced center wing boxes. Each inspection consisted of visual and ultrasonic inspection of the selective boron-epoxy reinforced center wings which included the inspection of the boron-epoxy laminates and the boron-epoxy reinforcement/aluminum structure adhesive bondlines. During the flight service monitoring period, the two C-130H aircraft accumulated more than 10,000 flight hours and no defects were detected in the inspections over this period. The successful performance of the C-130H aircraft with composite-reinforced center wings allowed the transfer of the responsibilities of inspecting and maintaining these two aircraft to the U. S. Air Force
The VA Health Care System: An Unrecognized National Safety Net
The dominance of local health care markets in conjunction with variable public funding results in a national patchwork of "safety nets" and beneficiaries in the United States rather than a uniform system. This DataWatch describes how the recently reorganized Department of Veterans Affairs serves as a coordinated, national safety-net provider and characterizes the veterans who are not supported by the market-based system
Program for establishing long-time flight service performance of composite materials in the center wing structure of C-130 aircraft. Phase 4: Ground/flight acceptance tests
The advantageous structural uses of advanced filamentary composites are demonstrated by design, fabrication, and test of three boron-epoxy reinforced C-130 center wing boxes. The advanced development work necessary to support detailed design of a composite reinforced C-130 center wing box was conducted. Activities included the development of a basis for structural design, selection and verification of materials and processes, manufacturing and tooling development, and fabrication and test of full-scale portions of the center wing box. Detailed design drawings, and necessary analytical structural substantiation including static strength, fatigue endurance, flutter, and weight analyses are considered. Some additional component testing was conducted to verify the design for panel buckling, and to evaluate specific local design areas. Development of the cool tool restraint concept was completed, and bonding capabilities were evaluated using full-length skin panel and stringer specimens
Addition of 24‐hour heart rate variability parameters to the Cardiovascular Health Study stroke risk score and prediction of incident stroke: The Cardiovascular Health Study
Background Heart rate variability (HRV) characterizes cardiac autonomic functioning. The association of HRV with stroke is uncertain. We examined whether 24‐hour HRV added predictive value to the Cardiovascular Health Study clinical stroke risk score (CHS‐SCORE), previously developed at the baseline examination. Methods and Results N=884 stroke‐free CHS participants (age 75.3±4.6), with 24‐hour Holters adequate for HRV analysis at the 1994–1995 examination, had 68 strokes over ≤8 year follow‐up (median 7.3 [interquartile range 7.1–7.6] years). The value of adding HRV to the CHS‐SCORE was assessed with stepwise Cox regression analysis. The CHS‐SCORE predicted incident stroke (HR=1.06 per unit increment, P=0.005). Two HRV parameters, decreased coefficient of variance of NN intervals (CV%, P=0.031) and decreased power law slope (SLOPE, P=0.033) also entered the model, but these did not significantly improve the c‐statistic (P=0.47). In a secondary analysis, dichotomization of CV% (LOWCV% ≤12.8%) was found to maximally stratify higher‐risk participants after adjustment for CHS‐SCORE. Similarly, dichotomizing SLOPE (LOWSLOPE <−1.4) maximally stratified higher‐risk participants. When these HRV categories were combined (eg, HIGHCV% with HIGHSLOPE), the c‐statistic for the model with the CHS‐SCORE and combined HRV categories was 0.68, significantly higher than 0.61 for the CHS‐SCORE alone (P=0.02). Conclusions In this sample of older adults, 2 HRV parameters, CV% and power law slope, emerged as significantly associated with incident stroke when added to a validated clinical risk score. After each parameter was dichotomized based on its optimal cut point in this sample, their composite significantly improved prediction of incident stroke during ≤8‐year follow‐up. These findings will require validation in separate, larger cohorts. Keywords: autonomic nervous system, clinical stroke risk model, heart rate variability, prediction, predictors, risk prediction, risk stratification, strok
Iridium Coatings for the Protection of Graphite Re-Entry Structures
Because of its high strength-to-weight ratio and other desirable features, graphite is desirable for use as structural components that are to be exposed to a high-temperature environment. At elevated temperatures, however, graphite reacts with oxidizing atmospheres, and smooth surfaces having specific engineering properties are degraded into eroded surfaces of lower efficiency.
It has been demonstrated that iridium can be used to protect graphite in air at temperatures to 3600 F for 1 hour or more. Battelle has been conducting a program for the Air Force Materials Laboratory to study the application of iridium and iridium-alloy coatings to graphite, based on a comb ined plasma-arc deposition and gas-pressure bonding process. A comprehensive prog ram involving the development, fabrication, and testing of these coatings is described
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Association of acculturation with cardiac structure and function among Hispanics/Latinos: a cross-sectional analysis of the echocardiographic study of Latinos.
OBJECTIVE:Hispanics/Latinos, the largest immigrant population in the USA, undergo the process of acculturation and have a large burden of heart failure risk. Few studies have examined the association of acculturation on cardiac structure and function. DESIGN:Cross-sectional. SETTING:The Echocardiographic Study of Latinos. PARTICIPANTS:1818 Hispanic adult participants with baseline echocardiographic assessment and acculturation measured by the Short Acculturation Scale, nativity, age at immigration, length of US residence, generational status and language. PRIMARY AND SECONDARY OUTCOME MEASURES:Echocardiographic assessment of left atrial volume index (LAVI), left ventricular mass index (LVMI), early diastolic transmitral inflow and mitral annular velocities. RESULTS:The study population was predominantly Spanish-speaking and foreign-born with mean residence in the US of 22.7 years, mean age of 56.4 years; 50% had hypertension, 28% had diabetes and 44% had a body mass index >30 kg/m2. Multivariable analyses demonstrated higher LAVI with increasing years of US residence. Foreign-born and first-generation participants had higher E/e' but lower LAVI and e' velocities compared with the second generation. Higher acculturation and income >20K were associated with higher LVMI, LAVI and E/e' but lower e' velocities. Preferential Spanish-speakers with an income <20K had a higher E/e'. CONCLUSIONS:Acculturation was associated with abnormal cardiac structure and function, with some effect modification by socioeconomic status
Are Economic Pressures on University Press Acquisitions Quietly Changing the Shape of the Scholarly Record?
The monograph remains central to humanities and qualitative social science (HSS) research as the form most suitable for the long-form argument and, crucially, as foundational to the tenure process in these fields. University and other scholarly presses have played a vital role in supporting the publication of scholarly monographs where such narrow research is not seen as being as commercially viable as, for example, journals. While there appears to be an erosion of traditional revenue streams, new funding models are not yet recuperating costs for scholarly monographs. Library budgets continue to tighten, with new collection strategies taking hold, putting strain on monograph purchasing where libraries were central supporters of the form. We wanted to know what these economic pressures meant for the ways in which editors at university and other scholarly presses choose to acquire books. Recent research has addressed the impact of cooperative library purchasing, the role of American university presses in shaping the monograph, effects of new business models and approaches to access, and the costs of producing scholarly monographs. But there has been little exploration into editorial practices as a part of this larger ecosystem. This paper presents preliminary results from a pilot study exploring the connection between revenue, the economics of publishing scholarly monographs, and the behaviors and choices of acquisitions editors
PDA and the University Press
Patron-driven acquisitions (PDA), also referred to as demand-driven acquisitions (DDA), is a relatively recent development in the management of the book supply chain for academic libraries. In its simplest form, PDA is a just-in-time method, and an accompanying set of operational procedures, for acquiring library materials based on direct or indirect patron input. PDA has significant implications for the economics of publishers. This report surveys the marketplace for university press titles, identifies the share of books being sold to academic libraries, establishes a framework to analyze the impact PDA on university presses, and recommends strategies that scholarly publishers can adopt to address this transformation in one of the industry’s most significant markets.The Andrew W. Mellon Foundatio
Association of alcohol consumption after development of heart failure with survival among older adults in the Cardiovascular Health Study
Importance: More than 1 million older adults develop heart failure annually. The association of alcohol consumption with survival among these individuals after diagnosis is unknown.
Objective: To determine whether alcohol use is associated with increased survival among older adults with incident heart failure.
Design, Setting, and Participants: This prospective cohort study included 5888 community-dwelling adults aged 65 years or older who were recruited to participate in the Cardiovascular Health Study between June 12, 1989, and June 1993, from 4 US sites. Of the total participants, 393 individuals had a new diagnosis of heart failure within the first 9 years of follow-up through June 2013. The study analysis was performed between January 19, 2016, and September 22, 2016.
Exposures: Alcohol consumption was divided into 4 categories: abstainers (never drinkers), former drinkers, 7 or fewer alcoholic drinks per week, and more than 7 drinks per week.
Primary Outcomes and Measures: Participant survival after the diagnosis of incident heart failure.
Results: Among the 393 adults diagnosed with incident heart failure, 213 (54.2%) were female, 339 (86.3%) were white, and the mean (SD) age was 78.7 (6.0) years. Alcohol consumption after diagnosis was reported in 129 (32.8%) of the participants. Across alcohol consumption categories of long-term abstainers, former drinkers, consumers of 1-7 drinks weekly and consumers of more than 7 drinks weekly, the percentage of men (32.1%, 49.0%, 58.0%, and 82.4%, respectively; P \u3c .001 for trend), white individuals (78.0%, 92.7%, 92.0%, and 94.1%, respectively, P \u3c. 001 for trend), and high-income participants (22.0%, 43.8%, 47.3%, and 64.7%, respectively; P \u3c .001 for trend) increased with increasing alcohol consumption. Across the 4 categories, participants who consumed more alcohol had more years of education (mean, 12 years [interquartile range (IQR), 8.0-10.0 years], 12 years [IQR, 11.0-14.0 years], 13 years [IQR, 12.0-15.0 years], and 13 years [IQR, 12.0-14.0 years]; P \u3c .001 for trend). Diabetes was less common across the alcohol consumption categories (32.1%, 26.0%, 22.3%, and 5.9%, respectively; P = .01 for trend). Across alcohol consumption categories, there were fewer never smokers (58.3%, 44.8%, 35.7%, and 29.4%, respectively; P \u3c .001 for trend) and more former smokers (34.5%, 38.5%, 50.0%, and 52.9%, respectively; P = .006 for trend). After controlling for other factors, consumption of 7 or fewer alcoholic drinks per week was associated with additional mean survival of 383 days (95% CI, 17-748 days; P = .04) compared with abstinence from alcohol. Although the robustness was limited by the small number of individuals who consumed more than 7 drinks per week, a significant inverted U-shaped association between alcohol consumption and survival was observed. Multivariable model estimates of mean time from heart failure diagnosis to death were 2640 days (95% CI, 1967-3313 days) for never drinkers, 3046 days (95% CI, 2372-3719 days) for consumers of 0 to 7 drinks per week, and 2806 (95% CI, 1879-3734 days) for consumers of more than 7 drinks per week (P = .02). Consumption of 10 drinks per week was associated with the longest survival, a mean of 3381 days (95% CI, 2806-3956 days) after heart failure diagnosis.
Conclusions and Relevance: These findings suggest that limited alcohol consumption among older adults with incident heart failure is associated with survival benefit compared with long-term abstinence. These findings suggest that older adults who develop heart failure may not need to abstain from moderate levels of alcohol consumption
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