14,198 research outputs found
Hypersonic reentry vehicle Patent
Aerodynamic configuration of reentry vehicle heat shield to provide longitudinal and directional stability at hypersonic velocitie
Investigation of the basic foundations of masers and lasers
Research work on the theory of lasers and masers is reported. Special attention is given to technological applications of laser theory
The Detectability of Gamma-Ray Bursts and Their Afterglows at Very High Redshifts
There is increasingly strong evidence that gamma-ray bursts (GRBs) are
associated with star-forming galaxies, and occur near or in the star-forming
regions of these galaxies. These associations provide indirect evidence that at
least the long GRBs detected by BeppoSAX are a result of the collapse of
massive stars. The recent evidence that the light curves and the spectra of the
afterglows of GRB 970228 and GRB 980326 appear to contain a supernova
component, in addition to a relativistic shock wave component, provide more
direct clues that this is the case. Here we establish that GRBs and their
afterglows are both detectable out to very high redshifts (z > 5).Comment: To appear in Proc. of the 10th Annual October Astrophysics Conference
in Maryland: Cosmic Explosions, 4 pages, LaTe
Construction of the Variability -> Luminosity Estimator
We present a possible Cepheid-like luminosity estimator for the long-duration
gamma-ray bursts based on the variability of their light curves.Comment: To appear in Procs. of Gamma-Ray Bursts in the Afterglow Era: 2nd
Workshop, 3 pages, 2 figures, LaTe
Gamma-Ray Bursts as a Probe of Cosmology
We show that, if the long GRBs are produced by the collapse of massive stars,
GRBs and their afterglows may provide a powerful probe of cosmology and the
early universe.Comment: 6 pages, 5 PostScript figures. To appear in the proceedings of the
October 2000 Rome Workshop on Gamma-Ray Bursts in the Afterglow Er
The effects of Bodymax high-repetition resistance training on measures of body composition and muscular strength in active adult women
This is the author's PDF version of an article published in Journal of strenght and conditioning research in 2003. The definitive version is available at http://www.nsca-jscr.orgThe purpose of this study was to investigate the effects of a light, high-repetition resistance-training program on skinfold thicknesses and muscular strength in women. Thirty-nine active women (mean age 38.64 +/- 4.97 years) were randomly placed into a resistance-training group (RT; n = 20) or a control group (CG; n = 19). The RT group performed a resistance-training program called Bodymax for 1 hour, 3 d.wk(-1), which incorporated the use of variable free weights and high repetitions in a group setting. The CG group continued its customary aerobic training for 1 hour 3 d.wk(-1). Five skinfold and 7 muscular strength measures were determined pretraining and after 12 weeks of training. Sum of skinfolds decreased (-17 mm; p < 0.004) and muscular strength increased (+57.4 kg; p < 0.004) in the RT group. Effect sizes for individual skinfold sites and strength measures were "medium" and "high," respectively. Bodymax is an effective resistance-training program for reducing skinfold thickness and increasing muscular strength in active women. Therefore, women with a similar or lower-activity status should consider incorporating such training into their regular fitness programs
Reality-monitoring characteristics in confirmed and doubtful allegations of abuse
According to reality-monitoring theory, memories of experienced and imagined events are qualitatively different, and can be distinguished by children from the age of 3. Across three studies, a total of 119 allegations of sexual abuse by younger (aged 3-8) and older (aged 9-16) children were analyzed for developmental differences in the presence of reality-monitoring criteria, which should characterise descriptions of experienced events. Statements were deemed likely or unlikely to be descriptions of actual incidents using independent case information (e.g., medical evidence). Accounts by older children consistently contained more reality-monitoring criteria than those provided by younger children, and age differences were particularly strong when the cases were deemed doubtful (Studies 1 and 2)
Modelling treatment, age- and gender-specific recovery in acute injury studies
Background: Acute injury studies often measure physical ability repeatedly over
time through scores that have a finite range. This can result in a faster score change
at the beginning of the study than towards the end, motivating the investigation of
the rate of change. Additionally, the bounds of the score and their dependence on
covariates are often of interest.
Methods: We argue that transforming bounded data is not satisfactory in some
settings. Motivated by the Collaborative Ankle Support Trial (CAST), which investigated
different methods of immobilisation for severe ankle sprains, we developed a
model under the assumption that the recovery rate at a specific time is proportional to
the current score and the remaining score. This model enables a direct interpretation
of the covariate effects. We have re-analyzed the CAST data using these improved
methods, and explored novel relationships between age, gender and recovery rate.
Results: We confirm that using below knee cast is advantageous compared with a
tubular bandage in relation with the recovery rate. An age and gender effect on the
recovery rate and the maximum achievable score is demonstrated, with older female
patients recovering less fast (age-effect: -0.21, 95% confidence interval (CI) [-0.28,-
0.14]; gender effect: -0.06, CI [-0.12,-0.004]) and achieving a lower maximum score
(age-effect: -8.07, CI [-11.68,-4.01]; gender-effect: -5.34, CI [-8.18, -2.50]) than younger
male patients.
Conclusions: Our model is able to accurately model repeated measurements on the
original scale, while accounting for the bounded nature of a score. We demonstrate
that recovery in acute injury trials can differ substantially by age and gender. Older
female patients are less likely to recover well from a sprain
What happens when interviewers ask repeated questions in forensic interviews with children alleging abuse?
This study was designed to explore 1) the ways in which interviewers refocus alleged victims of abuse on their previous responses and 2) how children responded when they were refocused on their previous responses. Transcripts of 37 forensic interviews conducted by British police officers trained using the best practices spelled out in the Memorandum of Good Practice were examined. The instances in which interviewers asked repeated questions were isolated and coded into categories with respect to the reasons why interviewers needed to ask the repeated question (i.e., there was no apparent reason, to challenge a child’s response, clarification, no answer the first time the question was asked, digression, or compound question). The children’s responses to the repeated questions were further categorised into mutually exclusive categories (i.e., elaboration, repetition, contradiction, or no answer). On average interviewers asked children 8 repeated questions per interview. Most of the time interviewers asked repeated questions to challenge a previous response (62%), but they were also sometimes asked for no apparent reason (20%). Children repeated previous responses or elaborated on a previous response 81% of the time and contradicted themselves 7% of the time when re-asked the same question. We conclude that children did not appear unduly pressured to change their answers, and, more importantly, did not contradict themselves when interviewers attempted to refocus them on particular responses
The reproducibility of perceptually regulated exercise responses during short-term cycle ergometry
This is the author's PDF version of an article published in International journal of sports medicine in 2004. The definitive version is available at www.thieme-connect.com.The purpose of this study was to assess the reproducibility over four trials of perceptually regulated exercise intensity during short-term cycle ergometry. Recent research has suggested that an improvement in the reproducibility (better agreement) of the exercise output would be observed with a repeated practice of using regulatory tools such as Borg’s 6-20 rating of perceived exertion (RPE) scale. Eighteen healthy active volunteers (nine males mean age (± SD) 24.7 ± 3.4 yr, and nine females 27.6 ± 5.4 yr) completed four identical intermittent effort production trials on a cycle ergometer, over a period of two-three weeks, with all trials being between three and five days apart. After warm-up, the volunteers were asked to produce four x three-minute bouts of exercise at RPE levels: 13, 15, 9, and 17 (in this order). Power output (W), percentage maximum heart rate reserve (%MHRR), and oxygen consumption (VO2; ml•kg-1•min-1) were recorded in the final minute of each bout. Analysis revealed that the 95% limits of agreement (LoA) between repeated trials did not decrease for the objective markers of exercise intensity, remaining wide throughout. In the worst case comparisons the LoA represented changes (expressed as a proportion of the mean of two trials) of up to 58.3% in power output (T2 vs. T3 at RPE 9), 65.5% in %MHRR (T1 vs. T2 at RPE 13) and 36.5% in VO2 (T3 vs. T4 at RPE 17). These findings question the use of ratings of perceived exertion to regulate exercise effort. That the reproducibility of effort is also not seen to improve with practice raises doubts over the validity of using the RPE scale for providing training intensities for this type of exercise.This article was submitted to the RAE2008 for the University of Chester - Allied Health Professions and Studies
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