4,018 research outputs found
Rape and Posttraumatic Stress Disorder (PTSD): Examining the Mediating Role of Explicit Sex-Power Beliefs for Men Versus Women
Many rape survivors exhibit symptoms of post-traumatic stress disorder (PTSD), and recent literature suggests survivors\u27 beliefs about sex and control may affect PTSD symptoms. The present study examined beliefs about sex and power as potential mediators of the relationship between rape and PTSD symptoms for men versus women. Participants (N = 782) reported lifetime history of rape, current PTSD symptoms, and beliefs about sex and power. Women reported higher levels of lifetime history of rape than men (19.7% for women; 9.7% for men). While rape history predicted PTSD symptoms for both genders, beliefs about sex and power were shown to be a significant partial mediator of this relationship for men, but not for women. Results extend the literature on rape and PTSD by suggesting that survivors\u27 beliefs about sex and power are connected and can affect their PTSD symptoms. Additionally, results illustrate how sexual violence against men may reaffirm male gender roles that entail power and aggression, and ultimately affect trauma recovery
Momentum Analyticity and Finiteness of the 1-Loop Superstring Amplitude
The Type II Superstring amplitude to 1-loop order is given by an integral of
-functions over the moduli space of tori, which diverges for real
momenta. We construct the analytic continuation which renders this amplitude
well defined and finite, and we find the expected poles and cuts in the complex
momentum plane.Comment: 10pp, /UCLA/93/TEP/
Hydrodynamic propulsion of human sperm
The detailed fluid mechanics of sperm propulsion are fundamental to our understanding of reproduction. In this paper, we aim to model a human sperm swimming in a microscope slide chamber. We model the sperm itself by a distribution of regularized stokeslets over an ellipsoidal sperm head and along an infinitesimally thin
flagellum. The slide chamber walls are modelled as parallel plates, also discretized by a distribution of regularized stokeslets. The sperm flagellar motion, used in our model,
is obtained by digital microscopy of human sperm swimming in slide chambers. We compare the results of our simulation with previous numerical studies of flagellar propulsion, and compare our computations of sperm kinematics with those of the actual sperm measured by digital microscopy. We find that there is an excellent quantitative match of transverse and angular velocities between our simulations and
experimental measurements of sperm. We also find a good qualitative match of longitudinal velocities and computed tracks with those measured in our experiment. Our computations of average sperm power consumption fall within the range obtained by other authors. We use the hydrodynamic model, and a prototype flagellar motion derived from experiment, as a predictive tool, and investigate how sperm kinematics are affected by changes to head morphology, as human sperm have large variability in head size and shape. Results are shown which indicate the increase in predicted straight-line velocity of the sperm as the head width is reduced and the increase in lateral movement as the head length is reduced. Predicted power consumption, however, shows a minimum close to the normal head aspect ratio
Resistance Training Recovery: Considerations for Single vs. Multi-joint Movements and Upper vs. Lower Body Muscles
International Journal of Exercise Science 8(1) : 85-96, 2015. This study examined muscle recovery patterns between single-joint (SJ) versus multi-joint (MJ), and upper-body (UB) versus lower-body (LB) exercises and the utility of perceptual measures (ratings of perceived exertion (RPE) and perceived recovery scale (PRS)) to assess recovery status. A 10 rep max (10-RM) was determined for 6 SJ and 4 MJ exercises (5 UB and 5 LB) for male recreational weightlifters (n = 10). Participants completed a baseline protocol including 8 repetitions at 85% of 10-RM followed by a set to failure with 100% of 10-RM. In a counter-balanced crossover design, participants returned at 24 or 48 h to repeat the protocol. PRS and RPE were assessed following the first and second sets of each exercise respectively. Wilcoxon matched pair signed-rank tests determined performance improved (p \u3c 0.05) for every lift type category from 24 to 48 h, but the only difference in ∆ repetitions from baseline at the same time point was between MJ (-1.7 ± 1.5 repetitions ) and SJ (-0.5 ± 1.8 repetitions ) at 24 h (p = 0.037). Higher RPE and lower PRS estimations (p \u3c 0.05) support the utility of perceptual measures to gauge recovery as the only between group differences were also found between MJ and SJ at 24 h. Eighty percent of participants completed within 1 repetition of baseline for all exercises at 48 h except bench press (70%) and deadlift (60%); suggesting 72 h of recovery should be implemented for multi-joint barbell lifts targeting the same muscle groups in slower recovering lifters
Caffeine Alters RPE-Based Intensity Production
International Journal of Exercise Science 12(6): 412-424, 2019. This study examined effects of caffeine (CAF) on power output (PO) selection and associated physiological responses during cycling at moderate and high intensities prescribed by RPE (0-10 scale). Participants (n = 9) (VO2peak: 55.4 ± 6.32 mL · kg-1 · min-1) cycled for 20 min at RPE4 and 20 min at RPE7 separated by 10 min recovery following caffeine (CAF) (6 mg · kg-1) and placebo (PLA) ingestion. PO, HR, serum lactate [La], VO2, VE, and RER were recorded every 5 min. Session RPE (S-RPE) was recorded following 10 min recovery. Repeated-measures ANOVA’s, 2 (trial) x 4 (time pt), showed significantly greater PO during RPE4 for CAF (130 ± 23 W) vs PLA (112 ± 26 W) and during RPE7 (CAF: 165 ± 37 vs PLA: 143 ± 41 W). Overall HR, VO2, and VE were significantly greater for CAF vs PLA during RPE7. RER for RPE4 and RPE7 were not significantly different (CAF vs PLA). Overall [La] was significantly greater for CAF during RPE4 (CAF: 2.32 ± 0.94 vs PLA: 1.73 ± 1.09) and RPE7 (CAF: 3.22 ± 1.44 vs PLA: 2.22 ± 1.49). Paired T-tests for S-RPE revealed no significant difference for RPE4 (CAF: 4.0 ± 0.5 vs PLA: 3.7 ± 0.5) or RPE7 (CAF: 7.1 ± 0.3 vs PLA: 6.9 ± 0.6) despite greater PO for CAF. Although individual responses varied, the current study indicates caffeine ingestion results in elevated self-selected PO with significant systematic changes in associated physiological responses particularly at a higher intensity (RPE7)
Distribution of Campylobacter and Arcobacter in Livestock
We designed polymearse chain reaction (PCR) primers to distinguish Campylobacter jejuni from Campylobacter coli and to differentiate Arcobacter from other species of Campylobacter. We applied these PCR methods to estimate their prevalence in feces of healthy cattle and hogs and to identify risk factors for infection. For cattle, C. jejuni (23%), Arcobacter (11%), and C. coli (1.57%) were detected in healthy dairy cows (n=1,628). Campylobacter coli (69%), Arcobacter (46%) and C. jejuni (0.28%) were found in market weight hogs (n=1,057). This indicates the widespread distribution of these microbes livestock
Occupational Interest Patterns and Personality Styles of Freshman Student-Athletes
The existence and relationship of common personality styles and occupational orientations were explored. The study considered Holand's (1973) vocational theory and Strack's (1991) eight basic personality types. Student-athletes (n=36) and non-athletes (n=17) enrolled in a freshman seminar for physical education majors (males = 63%) completed the Personality Adjective Check List (Straclk, 1991) and the Strong Interest Inventory (Hansen & Campbell, 1985). The results suggest that student-athletes and non-athletes differ on several personality and occupacional variables and that personality sryle has an important relationship to occupational orientation and interests. A specific profile for athletes based on personality and vocational type did not emerge. Implications for athletic counseling professionals were discussed
Three Week Hypergravity Training Intervention Decreases Ground Contact Time During Repeated Jumping and Improves Sprinting and Shuttle Running Performance
International Journal of Exercise Science 9(2): 149-158, 2016. This study examined the effects of a non-traditional training method, hypergravity training (HT), on anaerobic performance. Highly active men (n = 9) completed a 3 week HT protocol in which weighted vests were worn 8 h/day, 4+ days/week separate from training. Vest loads were 11.2 ± 0.6% of body mass during week one, and increased to 13.2 ± 0.7% (week 2), and 16.1 ± 0.4% (week 3). Performance testing included power clean 1-RM (PC), counter movement jumps, 4 continuous jumps, 36.6 m sprints (SP), a 137.2 m short shuttle run (SSR), and a 274.3 m long shuttle run (LSR). A 3 week non-hypergravity training period (NHT) proceeded HT. Baseline SP improved from 4.69 ± 0.29 s to 4.58 ± 0.22 s post-treatment, and regressed after NHT (4.69 ± 0.24 s) (p = 0.006, ES = 1.80). Improvements in SSR (p = 0.012, ES = 1.71) occurred from baseline (26.7 ± 1.5 s) to post-treatment (26.2 ± 1.4 s), followed by a return to near-baseline values (26.9 ± 1.8 s). Jumping tasks displayed similar trends, but no statistical differences and modest effect sizes (0.51 - 0.62) were found except for improved ground contact time during repeated jumps post-HT (ES = 2.26). PC and LSR performances did not improve. Three weeks of HT significantly enhanced short running task performances and decreased ground contact time between 4 continuous jumps. HT may be incorporated into training programs prior to key points in an athletic season without hindering the quality of regular training session activities
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