617 research outputs found
Study to define unsteady flow fields and their statistical characteristics
Preliminary estimates of space shuttle fluctuating pressure environments were made based on analyses of wind tunnel data, and empirical prediction techniques. Particular emphasis was given to the external tank and solid rocket boosters for the transonic speed regime during launch of a parallel-burn space shuttle configuration. Predicted environments are presented as space-averaged zonal profiles with progressive shading from zone to zone to illustrate spatial variations in the magnitude of the fluctuating pressure coefficient over the surfaces of the external tank and solid rocket boosters. Predictions are provided for the transonic Mach number range from 0.8 equal to or less than M sub infinity equal to or less than 1.5, and for supersonic Mach numbers of 2.0 and 3.0
Analysis of screeching in a cold flow jet experiment
The screech phenomenon observed in a one-sixtieth scale model space shuttle test of the solid rocket booster exhaust flow noise has been investigated. A critical review is given of the cold flow test data representative of Space Shuttle launch configurations to define those parameters which contribute to screech generation. An acoustic feedback mechanism is found to be responsible for the generation of screech. A simple equation which permits prediction of screech frequency in terms of basic testing parameters such as the jet exhaust Mach number and the separating distance from nozzle exit to the surface of model launch pad is presented and is found in good agreement with the test data. Finally, techniques are recommended to eliminate or reduce the screech
Modeling and Testing of Docking and Berthing Mechanisms
The Contact Dynamics Simulation Laboratory (CDSL) of the Marshall Space Flight Center provides for refined hardware-in-the-loop real-time simulation of docking and berthing mechanisms and associated control systems. This facility is employed to verify the performance of docking/berthing mechanisms during Earth-orbit operations, determine the capture envelope of dockingherthing devices, measure contact loads at vehicle interfaces, and evaluate visual cues for man-in-the-loop operations. The CDSL has developed test verified analytical models of such systems as the ISS Common Berthing Mechanism and HST Three Point Docking Mechanism. This paper will describe the modeling and test techniques employed at the CDSL and present results from recent programs
Impact of community-driven interventions on dietary and physical activity outcomes among a cohort of adults in a rural Appalachian county in Eastern Kentucky, 2019–2022
Several environmental level factors exacerbate poor health outcomes in rural populations in the United States, such as lack of access to healthy food and locations to be physically active, which support healthy choices at the individual level. Thus, utilizing innovative place-based approaches in rural locations is essential to improve health outcomes. Leveraging community assets, like Cooperative Extension, is a novel strategy for implementing community-driven interventions. This prospective cohort study (n = 152), recruited in 2019 and surveyed again in 2020 and 2021, examined individual level changes in diet and physical activity in one rural Appalachian county. During this time, multiple community-driven interventions were implemented alongside Cooperative Extension and several community partners. Across the three-year study, the cohort indicated increases in other vegetables and water and reductions in fruits and legumes. There were also reductions in less healthy items such as French fries and sugar-sweetened beverages. The cohort also reported being less likely to engage in physical activity. Our findings suggest that key community-driven programs may have indirect effects on dietary and physical activity choices over time. Outcomes from this study are relevant for public health practitioners and community organizations working within rural Appalachian communities to address health-related behaviors
Specialized odorant receptors in social insects that detect cuticular hydrocarbon cues and candidate pheromones.
Eusocial insects use cuticular hydrocarbons as components of pheromones that mediate social behaviours, such as caste and nestmate recognition, and regulation of reproduction. In ants such as Harpegnathos saltator, the queen produces a pheromone which suppresses the development of workers' ovaries and if she is removed, workers can transition to a reproductive state known as gamergate. Here we functionally characterize a subfamily of odorant receptors (Ors) with a nine-exon gene structure that have undergone a massive expansion in ants and other eusocial insects. We deorphanize 22 representative members and find they can detect cuticular hydrocarbons from different ant castes, with one (HsOr263) that responds strongly to gamergate extract and a candidate queen pheromone component. After systematic testing with a diverse panel of hydrocarbons, we find that most Harpegnathos saltator Ors are narrowly tuned, suggesting that several receptors must contribute to detection and discrimination of different cuticular hydrocarbons important in mediating eusocial behaviour.Cuticular hydrocarbons (CHC) mediate the interactions between individuals in eusocial insects, but the sensory receptors for CHCs are unclear. Here the authors show that in ants such as H. saltator, the 9-exon subfamily of odorant receptors (HsOrs) responds to CHCs, and ectopic expression of HsOrs in Drosophila neurons imparts responsiveness to CHCs
Sugar-Sweetened Beverage Consumption among Adults in Rural Appalachia
Sugar-sweetened beverage (SSB) consumption is decreasing nationally, yet intakes remain high in certain sub-populations as new varieties of SSBs are introduced. This study aims to expand on SSB intake patterns among adults living in Appalachia to develop policy, systems, and environmental (PSE) interventions to reduce consumption. Baseline cohort surveys were conducted to examine beverage consumption patterns of adults in one rural Appalachian county in Kentucky using a validated BEVQ-15 instrument. Ages were collapsed into three generational groups – Millennials (22–38 years), Generation X (39–54 years), and Boomers/Silents (≥55 years). Over half (n = 81; 54%) of the sample (n = 150) were Boomers/Silents. Age was a significant predictor of SSB consumption, with Millennials drinking more daily calories of SSB compared to older adults (329.2 kcal v 157.0 kcal v 134.6 kcal, p = 0.05); a significant amount of those calories coming from non-soda SSBs. Millennials were twice as likely to drink sweetened fruit juice drinks (p = 0.0002) and energy drinks (p = 0.01) daily and consumed six times more daily calories from sweetened fruit juice drinks than the other groups (73.5 kcal v 11.1 kcal v 8.0 kcal, p \u3c 0.01). To our knowledge, this is the first study to show beverage choices and consumption patterns in Appalachian adults vary by age and non-soda SSBs are significant sources of added sugar. These findings inform PSE interventions for reducing SSB consumption, such as tailored marketing approaches and technology-based strategies, within a unique setting, and offer insight for nutrition educators and public health professionals working within rural, remote communities
Physical Activity Barriers and Assets in Rural Appalachian Kentucky: A Mixed-Methods Study
Obesity is an increasing public health concern in the U.S. and a contributor to chronic illness, with trends revealing a rise in adult obesity and chronic disease rates among the most vulnerable and disadvantaged populations, including those in rural communities. A mixed-methods approach was used to examine perspectives on perceived physical activity barriers, resources, and level of community support. Researchers utilized the socioecological model to examine the multiple domains that support physical activity in rural Appalachia. The present study focuses on baseline data, including a cohort survey to assess physical activity, health status, and barriers to physical activity, and five focus groups with elected community leaders, community residents, members, and key stakeholders to assess perspectives on physical activity barriers and resources within the county. The cohort survey sample (N = 152) reported a median of 6 barriers (range 0–13) to participating in at least 30 min of physical activity daily. The qualitative analysis yielded three overarching themes related to physical activity participation: lack of motivation, physical environment, and cultural barriers. This mixed-methods study revealed the challenges and perceptions among rural residents across the socioecological model when assessing physical inactivity. Findings can be used to tailor future interventions focused on expanding social support, designing infrastructure, and creating policies that promote physical activity
Rural SNAP Participants and Food Insecurity: How Can Communities Leverage Resources to Meet the Growing Food Insecurity Status of Rural and Low-Income Residents?
The burden of obesity disproportionately influences poor health outcomes in rural communities in the United States. Various social and environmental factors contribute to inadequate food access and availability in rural areas, influencing dietary intakes and food insecurity rates. This study aims to identify patterns related to food insecurity and fruit and vegetable consumption within a SNAP-eligible and low-income, highly obese rural Appalachian community. A prospective cohort was implemented to identify gaps in resources addressing obesity and food insecurity challenges. SAS 9.4 software was used to examine differences in dietary intakes and shopping practices among SNAP participants. Among participants (n = 152), most reported an annual household income less than USD 20,000 (n = 90, 60.4%), 29.1% reported food insecurity, and 39.5% reported receiving SNAP benefits within the last month. The overall mean FV intake was 3.46 daily servings (95% CI: 3.06–3.91) among all participants. SNAP participation was associated with food insecurity (p = 0.007) and those participating in SNAP were two times more likely to report being food insecure (OR = 2.707, 95% CI: 1.317, 5.563), relative to non-participants. These findings further depict the need for intervention, as the burden of food insecurity persists. Tailoring health-promoting initiatives to consider rurality and SNAP participation is vital for sustainable success among these populations
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