615 research outputs found

    The impact of cockpit automation on crew coordination and communication. Volume 1: Overview, LOFT evaluations, error severity, and questionnaire data

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    The purpose was to examine, jointly, cockpit automation and social processes. Automation was varied by the choice of two radically different versions of the DC-9 series aircraft, the traditional DC-9-30, and the glass cockpit derivative, the MD-88. Airline pilot volunteers flew a mission in the simulator for these aircraft. Results show that the performance differences between the crews of the two aircraft were generally small, but where there were differences, they favored the DC-9. There were no criteria on which the MD-88 crews performed better than the DC-9 crews. Furthermore, DC-9 crews rated their own workload as lower than did the MD-88 pilots. There were no significant differences between the two aircraft types with respect to the severity of errors committed during the Line-Oriented Flight Training (LOFT) flight. The attitude questionnaires provided some interesting insights, but failed to distinguish between DC-9 and MD-88 crews

    Recruitment and baseline characteristics of the Community of Voices choir study to promote the health and well-being of diverse older adults.

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    Objective:To describe the recruitment and baseline results of the Community of Voices study that aims to examine the effect of a community choir intervention on the health and well-being of older adults from diverse racial/ethnic and socioeconomic backgrounds. Method:Using community-based participatory research methods, we recruited adults age 60 and over from 12 Administration on Aging-supported senior centers in San Francisco into a 2-arm cluster-randomized controlled trial of the community choir intervention. Multiple outreach methods were used. We tracked outreach, screening, and recruitment metrics and collected demographics and baseline outcomes via community-based, interviewer-administered surveys and performance measures of cognition, physical function, and psychosocial variables. Results:The study contacted 819 individuals, screened 636, and enrolled 390 diverse older adults over a 42-month, phased recruitment period. The mean age was 71.2 (SD = 7.3), and the majority were women. Two-thirds of the sample are non-white, and 20% of participants reported having financial hardship. Discussion:Outreach and recruitment methods used in the Community of Voices trial facilitated enrollment of a large proportion of minority and lower-SES older adults in the final sample. Similar recruitment approaches could serve as a model for recruiting diverse racial/ethnic and socioeconomic older adults into research

    Development and Validation of the Trauma-Related Cognitions Scale

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    Cognitive theories suggest the manner in which individuals process trauma-related information influences posttraumatic sequelae. Interpretations about trauma can be maladaptive and lead to cognitive distortions implicated in the development of posttraumatic stress disorder (PTSD) through the processes of overaccommodation and assimilation. Alternatively, adaptive interpretations about trauma through the process of accommodation can lead to post-trauma resilience and recovery. The Trauma-Related Cognitions Scale (TRCS) provides a measure of beliefs associated with these cognitive processes. The TRCS was developed over the course of four phases. During Phase 1, 94 items derived from previously validated trauma cognition/beliefs measures were aggregated with 40 items developed by the authors. Phase 2 investigated the TRCS factor structure by fitting exploratory factor analysis (EFA) models to data from a non-clinical sample, resulting in a reduced 69-item TRCS representing four factors: the three theoretical cognitive processes of overaccommodation, assimilation, and accommodation, and an additional optimism factor. Phases 3 and 4 fit confirmatory factor analysis (CFA) models of the 69-item TRCS in a new non-clinical and a clinical sample, respectively, and further validation analyses were conducted. Initial evidence suggests the TRCS is a valid and reliable measure of trauma beliefs. Continued validation can determine its utility in both research and clinical contexts

    Use of Alternative Tobacco Products in Multiethnic Youth from Jujuy, Argentina

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    This study examines alternative tobacco use among Latin American youth. A self-administered survey in a random sample of 27 schools was administered in 2004 in Jujuy, Argentina (N = 3218). Prevalence of alternative tobacco product use was 24.1%; 15.3% of youth used hand-rolled cigarettes, 7.8% smoked cigars, 2.3% chewed tobacco leaf and 1.6% smoked pipe. Among youth who never smoked manufactured cigarettes, alternative product use was rare (2.9%), except for chewing tobacco (22%). In multivariate logistic regression boys were more likely than girls to smoke pipe (OR = 3.1; 95% CI 1.1–8.7); indigenous language was associated with smoking hand-rolled cigarettes (OR = 1.4; 95% CI-1.1–1.9) and pipe (OR = 2.2; 95% CI 1.5–3.4). Working in tobacco sales was a risk factor for chewing tobacco (OR = 2.9; 95% CI: 1.7–4.9) and smoking hand-rolled cigarettes (OR = 1.4; 95% CI 1.1–1.8). Having friends who smoked was associated with chewing tobacco (OR = 1.8; 95% CI 1.0–3.2) and with smoking cigars (OR = 2.1; 95% CI 1.5–2.9). Current drinking and thrill-seeking orientation were associated with cigars and pipe smoking. Findings highlight the importance of surveillance of alternative tobacco products use and availability among youth and for addressing identified risk factors

    Interpretation of soil carbon and nitrogen dynamics in agricultural and afforested soils

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    Includes bibliographical references (pages 1627-1628).Interpretation of soil organic C (SOC) dynamics depends heavily on analytical methods and management systems studied. Comparison of data from long-term corn (Zea mays)-plot soils in Eastern North America showed mean residence times (MRTs) of SOC determined by 14C dating were 176 times those measured with 13C abundance following a 30-yr replacement of C3 by C4 plants on the same soils. However, MRTs of the two methods were related (r 2 = 0.71). Field 13C MRTs of SOC were also related (R 2 = 0.55 to 0.85) to those measured by 13CO2 evolution and curve fitting during laboratory incubation. The strong relations, but different MRTs, were interpreted to mean that the three methods sampled different parts of a SOC continuum. The SOC of all parts of this continuum must be affected by the same controls on SOC dynamics for this to occur. Methods for site selection, plant biomass, soil sampling and analysis were tested on agricultural, afforested-agriculture, and native forest sites to determine the controls on SOC dynamics. Soil-C changes after afforestation were −0.07 to 0.55 Mg C ha−1 yr−1 on deciduous sites and −0.85 to 0.58 Mg C ha−1 yr−1 under conifers. Soil N changes under afforestation ranged from −0.1 to 0.025 Mg N ha−1 yr−1 Ecosystem N accumulation was −0.09 to 0.08 Mg N ha−1 yr−1 Soil C and N sequestration but not plant biomass were related to soil Ca, Mg, and K contents. Comparative, independent assays of long-term plots provides information for concept testing and the confidence necessary for decision-makers determining C-cycle policies

    Simulating the dynamics of soil organic matter in long-term rotation plots of Saskatchewan and Alberta

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    Non-Peer ReviewedThis study used the Century soil organic matter (SOM) model to simulate the dynamics in soil organic carbon, nitrogen, and phosphorus in long-term crop rotation studies established in Saskatchewan and Alberta. Observed losses of organic C, N, and P in the top 30 cm of a Brown Chernozem under fallow-wheat (FW) were 8.2, 1.7, and 1.0 g m-1 y-1. Soil erosion was responsible for 47% of the organic-N losses. The Century model closely mimicked the direction and magnitude of SOM change, within 10% of measured values. Similar SOM declining trends were observed in a thin Black Chernozem under FW and continuous wheat (CW), although soil erosion losses were higher than in the Brown Chernozem. Soil organic matter increased in the Brown Chernozem under CW and in the Black Chernozem under zero-tillage. Under no-till, the organic C, N, and P accumulated at an average rate of 101.7, 5.3, and 2.0 g m-2 y-1. In comparison, the Century model predicted a depletion of organic-C and N in the Brown Chernozem under CW and of organic-C under no-till. Model sensitivity analyses indicated that the rate of erosion and the fixed rate of organic matter decomposition had greater effects than plant biomass production on soil organic matter levels. Under aggrading SOM conditions, the Century model predicted organic carbon accumulation only after the respiration rate for the slow organic matter fraction was reduced by 50%

    Measuring the neighborhood environment: associations with young girls' energy intake and expenditure in a cross-sectional study

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    <p>Abstract</p> <p>Background</p> <p>Neighborhood environments affect children's health outcomes. Observational methods used to assess neighborhoods can be categorized as indirect, intermediate, or direct. Direct methods, involving in-person audits of the neighborhoods conducted by trained observers, are recognized as an accurate representation of current neighborhood conditions. The authors investigated the associations of various neighborhood characteristics with young girls' diet and physical activity.</p> <p>Methods</p> <p>This study is based on a subset of participants in the Cohort Study of Young Girls' Nutrition, Environment and Transitions (CYGNET). In-person street audits were conducted within 215 girls' residential neighborhoods using a modified St. Louis Audit Tool. From the street audit data, exploratory factor analysis revealed five neighborhood scales: "mixed residential and commercial," "food and retail," "recreation," "walkability," and "physical disorder." A Neighborhood Deprivation Index was also derived from census data. The authors investigated if the five neighborhood scales and the Neighborhood Deprivation Index were associated with quartiles of total energy intake and expenditure (metabolic equivalent (MET) hours/week) at baseline, and whether any of these associations were modified by race/ethnicity.</p> <p>Results</p> <p>After adjustment for demographic characteristics, there was an inverse association between prevalence of "food and retail" destinations and total energy intake (for a one quartile increase, OR = 0.84, 95% CI 0.74, 0.96). Positive associations were also observed between the "recreation" and "walkability" scales with physical activity among Hispanic/Latina girls (for a one quartile increase in MET, OR = 1.94, 95% CI 1.31, 2.88 for recreation; OR = 1.71, 95% CI 1.11, 2.63 for walkability). Among African-American girls, there was an inverse association between "physical disorder" and physical activity (OR = 0.31, 95% CI 0.12, 0.80).</p> <p>Conclusions</p> <p>These results suggest that neighborhood food and retail availability may be inversely associated with young girls' energy intakes in contrast to other studies' findings that focused on adults. There is considerable variation in neighborhoods' influences on young girls' physical activity behaviors, particularly for young girls of different racial/ethnic backgrounds.</p

    Use of medical, surgical and complementary treatments among women with fibroids

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    OBJECTIVE: To examine the use of medical management, uterus-preserving surgery (UPS), and complementary treatments among women with uterine fibroids. STUDY DESIGN: Prospective cohort study of 933 premenopausal women ages 31-54 years with symptomatic fibroids who participated in the Study of Pelvic Problems, Hysterectomy, and Intervention Alternatives (SOPHIA) for an average of 4.3 years (SD 2.5 years). Incident use of fibroid treatments was determined through annual interviews. Linear regression models were used to compare changes in fibroid-related symptoms among women who underwent UPS versus those who did not undergo surgery. RESULTS: Participants were racially and ethnically diverse, with a mean age of 43 years. During study follow-up, 531 participants (57%) did not undergo UPS or hysterectomy, 250 (27%) had at least one UPS, and 152 (16%) underwent hysterectomy. Complementary and alternative treatments were commonly used, including exercise (45%), diet (34%), herbs (37%), and acupuncture (16%): participants reported significant symptom improvement and few side effects with these interventions. In multivariable linear regression models, women who did not undergo surgery during the study reported improvement in dyspareunia (p<.001), pelvic pain (p<.001), and menstrual cramps (p<.001). However, women who underwent UPS reported greater overall resolution of "pelvic problems" compared with women who did not have surgical treatment (difference in change score 1.18 on a four-point Likert scale, p<.001). CONCLUSION: UPS are effective treatments for women with fibroids, but many women use hormonal or complementary treatments and report significant symptom improvement without surgical intervention
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