2,516 research outputs found
Design of an all-attitude flight control system to execute commanded bank angles and angles of attack
A flight control system for use in air-to-air combat simulation was designed. The input to the flight control system are commanded bank angle and angle of attack, the output are commands to the control surface actuators such that the commanded values will be achieved in near minimum time and sideslip is controlled to remain small. For the longitudinal direction, a conventional linear control system with gains scheduled as a function of dynamic pressure is employed. For the lateral direction, a novel control system, consisting of a linear portion for small bank angle errors and a bang-bang control system for large errors and error rates is employed
The next generation of emergency management : proposal for a new model of emergency operations center for a growing regional emergency management system
The emergency operations center organizational model used by the Charlottesville/Albemarle/University of Virginia (CAUVA) Emergency Management Agency is organized around the various departments that staff the center. The EOC model has been used to coordinate small scale natural disasters and training exercises, but has never been used to coordinate a significant actual event. After-action reports of previous events and exercises have highlighted several functional deficiencies and have led some local and state officials to doubt the model\u27s ability to coordinate a significant event... The research process involved a literature and extant document review which discovered that there were four recognized EOC models. A survey of CAUVA EOC staff members was conducted and revealed that eight EOC functions needed improvement. A benchmark study was conducted of like-sized Virginia localities and it was determined that the incident command system/emergency support function (ICSIESF) EOC model was best the performing model. The final phase involved surveying the same group of CAUVA EOC staff members, presenting them with the list of deficiencies, the current CAUVA and best practice EOC models, and asking participants to choose which best practice components could be adopted to address found deficiencies. The survey results revealed that the ICSIESF EOC model was selected to be the model of choice for a growing, midsized city-county region. Although additional plan development and staff training will be required, the ICSIESF model may prove to be a more effective method to deal with a challenging natural or man-made disaster
A Comparative Evaluation of Gait between Children with Autism and Typically Developing Matched Controls
Anecdotal reports suggest children with autism spectrum disorder (ASD) ambulate differently than peers with typical development (TD). Little empirical evidence supports these reports. Children with ASD exhibit delayed motor skills, and it is important to determine whether or not motor movement deficits exist during walking. The purpose of the study was to perform a comprehensive lower-extremity gait analysis between children (aged 5–12 years) with ASD and age- and gender-matched-samples with TD. Gait parameters were normalized to 101 data points and the gait cycle was divided into seven sub-phases. The Model Statistic procedure was used to test for statistical significance between matched-pairs throughout the entire gait cycle for each parameter. When collapsed across all participants, children with ASD exhibited large numbers of significant differences (p \u3c 0.05) throughout the gait cycle in hip, knee, and ankle joint positions as well as vertical and anterior/posterior ground reaction forces. Children with ASD exhibited unique differences throughout the gait cycle, which supports current literature on the heterogeneity of the disorder. The present work supports recent findings that motor movement differences may be a core symptom of ASD. Thus, individuals may benefit from therapeutic movement interventions that follow precision medicine guidelines by accounting for individual characteristics, given the unique movement differences observed
Dynamic stability of space vehicles. Volume 14 - Testing for booster propellant sloshing parameters
Recommended procedures for stability, control, and structural loading analysis of large liquid fueled rocket booster sloshing parameter
Religiosity and Sexual Risk Behaviors Among Latina Adolescents: Trends from 1995 to 2008
Purpose: The purpose of this study was to determine trends in the influence of religiosity on sexual activity of Latina adolescents in the United States from 1995 to 2008 and to determine if differences existed between the Mexican American and other Latina groups.
Methods: The sample comprised the subset of unmarried, 15–21-year-old (mean 17 years) Latina female respondents in the 1995 (n=267), 2002 (n=306), and 2006–2008 (n=400) National Survey of Family Growth (NSFG) datasets. Associations between religiosity (importance of religion and service attendance) and history of ever having sex, number of sex partners, and age of sexual debut were investigated.
Results: Less than one half of Latinas in 1995 (44%) and in 2006–2008 (44%) reported that religion was very important to them, whereas in 2002, 50% reported it was important. Only in 1995 did Latinas who viewed religion as very important have a significantly lower level of sexual initiation. In 1995 and in 2006–2008, Latinas who held religion as very important had significantly fewer partners. In all three cohorts, the higher religious importance group had higher virgin survival rates. Across cohorts, approximately one third of respondents reported frequent religious attendance. In all cohorts, frequent attenders were less likely to have had sex, had fewer partners, and had older age at sexual debut. The survival rate as virgins for Mexican origin Latinas was higher in 1995 and 2002 compared to non-Mexican Latinas but was almost the same in 2006–2008.
Conclusions: Religiosity had a protective association with sexual activity among Latina adolescents. The association of importance of religion with sexual activity has diminished from 1995 to 2008, however, whereas the importance of service attendance has remained stable. The influence of religion was more apparent among the Latinas of Mexican origin, but this greater influence also diminished by 2006–2008
Ractopamine HCl improved cardiac hypertrophy but not poor growth, metabolic inefficiency, or greater white blood cells associated with heat stress in concentrate-fed lambs
Heat stress decreases livestock performance and well-being (Hahn, 1999; Nienaber and Hahn, 2007), causes metabolic dysfunction that decreases growth efficiency (O’Brien et al., 2010), and alters cardiovascular function (Crandall et al., 2008). Each year, heat stress costs the livestock industry up to $2.5 billion (St-Pierre et al., 2003). Ractopamine HCl acts as a nutrient repartitioning agent (Beermann, 2002); classified as a β adrenergic agonist (βAA), it shares pharmacological properties with adrenaline (Beermann, 2002). βAA increase muscle mass and decreases fat deposition through unknown mechanisms (Beermann, 2002). In feedlot cattle, they increase growth efficiency and improve carcass yield and merit (Scramlin et al., 2010; Buntyn et al., 2017), which increases profit and allows more meat to be produced from fewer animals. However, because βAA act via a stress system, it is unclear how the products affect animals under stress conditions. β1AA and β2AA can also cause tachycardia, heart palpitations, and arrhythmias (Sears, 2002). We hypothesize that β1AA combined with heat stress may overstimulate the adrenergic system, resulting is metabolic dysfunction and decreased performance. Sheep are a common model for cattle, and thus, the objective of this study was to determine the impact of ractopamine HCl on health and cardiovascular parameters, growth, and metabolic efficiency in feeder lambs
The Effect of Attentional Focus Instructions on Golf Swing Performance in Recreational Golfers
Previous research has addressed the effectiveness of attentional focus instructions in improving golf performance with a single training session. The purpose of the current study was to investigate the effect of external (EF) attentional focus instructions on recreational golfers’ performance over a distributed training period and extended retention interval. Performance was measured by club head velocity (CHV) and X-factor as both have been correlated with greater performance. The current study extends the work of An, Wulf, and Kim (2013), by increasing the training period and retention interval. It was hypothesized EF group would have greater CHV and X-factor measurements during the training and retention interval compared to a control (C) group. Repeated measures ANCOVA tested for significant differences in CHV and X-factor measures between EF and C groups. No significant main effects (time or group) or interactions were found during training period or retention tests for either CHV or X-factor. Future studies should determine if the cue used in the current study was appropriate for eliciting an improvement in performance, or if different components of the swing needs to be emphasized for greater performance improvements
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