Session A-3: Energy Conservation

This session will focus on the content and different activities that you can do with your students to meet the Next Generation Physical Science Standard 3: Energy. The focus will be on definitions of energy, conservation of energy, and the relationship between energy and forces. The content is appropriate for both middle and high school science students

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

Impaired H-Reflex Adaptations Following Slope Walking in Individuals With Post-stroke Hemiparesis

Background and Purpose: Short term adaptations in the Ia afferent-motoneuron pathway, as measured using the H-reflex, in response to altered ground reaction forces (GRFs) applied at the feet during slope walking have been observed in the non-impaired nervous system. The ability of the stroke-impaired nervous system to adapt to altered GRFs have not been examined. The purpose of this study was to examine the acute effects of altered propulsive and braking forces applied at the feet, which naturally occurs when walking on different slopes, on adaptations of the H-reflex pathway in individuals with chronic post-stroke hemiparesis

Neuromuscular Adaptations Following Slope Walking in Individuals Post-Stroke

Background: The excitability of the H-reflex pathway in the non-impaired nervous system can be augmented by altering the different parameters of a walking task, specifically slope. We sought to examine the adaptations in soleus H-reflex excitability and foot force control following an acute bout of upslope or downslope treadmill walking in people post-stroke compared to those who are non- impaired. Methods: We recruited 12 individuals with chronic post-stroke hemiparesis and 9 age-similar non- neurologically impaired individuals. Each subject was tested over 2 sessions separated by at least 7 days. For each session, subjects walked at a self-selected walking speed on an instrumented treadmill for 20 minutes under a level and then an upslope condition, or a level and then a downslope condition, with at least an hour rest between the conditions. The vertical component of ground reaction force was used to determine the stance and swing phase of the gait cycle. Peak propulsion and braking forces were analyzed offline for the first (T1) and last minute (T20) of each walking condition to examine adaptations in foot force control. Soleus H-reflexes (Hmax) were tested before and after each walking condition in the paretic legs of the post-stroke group and the right legs of the control group. To ensure consistency, a control M wave (Mmax) preceding the Hmax was kept constant across all conditions for each subject. Peak to peak amplitudes of the maximal H-reflexes and maximal M waves were measured offline and expressed as an Hmax/Mmax ratio. Results: The paretic legs generated higher propulsion force during upslope (11.75±1.04 %BW), but comparable propulsion forces during downslope, when compared to level walking (6.14±0.67 %BW). However, we did observe statistical significance in main effect for slope in paretic (F(2,22)=33.178, p\u3c0.001), non-paretic (F(1.144, 12.585)=23.246, p\u3c0.001) and non-impaired legs (F(1.137, 10.998)=22.766, p\u3c0.001). Pairwise comparisons between slope types indicated that on average, peak braking forces were higher when walking downslope and lower when walking upslope, when compared to level walking. We observed an overall change in Hmax/Mmax ratio following 20 minutes of walking, and the change was different for post-stroke compared to control group, as suggested by the significant interaction between time and group (F(1,19)=16.84, p=0.001). Conclusion: Our observations suggest that when the biomechanics of the walking task is altered, through adjusting the slope of the walking surface, paretic legs exhibit increased propulsion forces during upslope walking. Paretic propulsive forces were greatest in the upslope condition and lowest in the downslope condition. Regardless of group, individuals had greatest braking forces during the downslope condition and lowest during the upslope condition. We believe, based on current studies, that increased paretic propulsion forces in the upslope condition may be due to the increased difficulty of the environmental condition. In the level condition, spinal circuits in the stroke-impaired nervous system are trending towards adaptations similar to the non-impaired nervous system, such that the Hmax/Mmax ratios were depressed. However, in the more challenging upslope condition, adaptations of the paretic soleus H-reflexes were impaired such that the Hmax/Mmax ratios were trending towards elevated. Future studies will examine the optimal walking duration and degree of slope to induce neural adaptations, as well as determine any long-term retention of plasticity

Early Evidence on the use of Foreign Cash following the Tax Cuts and Jobs Act of 2017

The Tax Cuts and Jobs Act of 2017 (TCJA) imposes a mandatory repatriation tax on multinational firms’ unremitted foreign earnings, reducing internal capital market frictions through a deemed repatriation of unremitted foreign earnings and eliminating future repatriation tax costs. This change to the U.S. corporate tax system gives multinational firms access to lower cost internal capital (i.e., foreign cash). This study provides evidence that multinational firms with greater levels of pre-TCJA foreign cash increased their post-TCJA repurchases but did not change their shareholder dividends or capital expenditures. We further document that the increase in repurchases is driven by those firms that had greater pre-TCJA repatriation tax costs and firms in weaker financial health. This outcome is consistent with internal capital market theory and suggests a decrease in internal capital market frictions allows companies access to trapped foreign cash. However, our results suggest firms used the repatriated foreign cash on shareholder payouts rather than capital investment. This conflicts with a stated goal of the TCJA to spur domestic economic growth directly and highlights an unintended consequence of the TCJA

Manuscript has been retracted

International Journal of Exercise Science 7(2) : 128-139, 2014. Manuscript has been retracted

Suspected Malignant Hyperthermia and the Application of a Multidisciplinary Response

Purpose: Malignant hyperthermia (MH) is a critical and potentially life-threatening emergency associated with inhaled anesthetic and depolarizing neuromuscular blocker administration. This is a single center’s response to MH. Summary: When signs of MH are observed, a page for “anesthesia STAT-MH crisis” is called, triggering a multidisciplinary response, including the deployment of a Malignant Hyperthermia Cart. The MH cart and the delegation of duties allows nurses, physicians and pharmacists to quickly understand their role in the stabilization, transition and recovery of a suspected MH patient. Conclusion: This case highlights the importance of multi-disciplinary involvement in these rare, but potentially fatal, cases