Voluntary Web-Based Self-Assessment Quiz Use Improves Exam Performance, Especially for Learners with Low Prior Knowledge

We examined students’ voluntary use of digital self-assessment quizzes as a resource for learning in a large anatomy and physiology lecture course. Students (N = 238) could use 16 chapter quizzes and four analogous unit quizzes to rehearse and self-assess knowledge. Repeated use was uncommon (12%), as was lack of use (13%). Most students (75%) engaged in occasional use of self-assessment quiz items. Exam performance differed between repeated use (84%), occasional use (76%), and no use (72%) groups. Differences were greater among students who lacked prior knowledge of course topics. Quiz use improved performance more for low prior knowledge students, and differences increased over the semester. Overall, repeated users significantly outperformed occasional users (+7.5%) and non users (+11.9%) on course examshttps://digitalscholarship.unlv.edu/btp_expo/1023/thumbnail.jp

Physiological implications of natural versus induced arousal from torpor

During the hibernation season, animals oscillate between periods of torpor and periods of interbout arousal (IBA). During torpor, body temperature is often near 0° C and metabolism is severely depressed. Oxygen consumption, a proxy for aerobic metabolism, may fall to 1% of active values. Many physiological processes including cardiovascular, respiratory, and cellular functions nearly cease. During the IBA, euthermic body temperature is restored and most systemic and cellular processes function at fully active levels. The transition period between these two physiologically dissimilar states is called arousal. The rate of rewarming (RRW) during arousal was previously expected to progressively increase until a euthermic set point was approached. However, my data contradict this expectation. I monitored the body temperature (Tb) of goldenmantled ground squirrels (Spermophilus lateralis) housed at 4, 8, 12, and 16° C during natural arousals. The various housing temperatures facilitate manipulation of torpid Tb, since torpid Tb is usually within 1° C of ambient temperature (Ta). The maximum RRW, the time required to reach a maximum RRW, and the relative time index all demonstrated negative relationships with Ta. The Tb corresponding to maximal RRW demonstrated a positive relationship with Ta. One parameter was independent of ambient temperature. Squirrels reached maximal RRW when they had generated 30 to 40% of the heat required to reach a euthermic Tb. These data suggest that arousal is more constrained than expected and that both time and temperature influence the RRW. Much hibernation research involving arousal has been conduced on animals that were induced to arouse prematurely. Natural arousal from torpor occursspontaneously with highly predictable timing. However, animals can also be induced to arouse prematurely in response to various disturbances. While many investigations have used natural and induced arousals synonymously, direct comparisons of these two types of arousal have been lacking. I addressed the question of whether natural and prematurely induced arousals are the same. I compared the effects of ambient temperature on the dynamics of natural versus induced arousals. Arousal duration, maximum rewarming rate, and the variance associated with increases in body temperature increased during induced arousals. Prematurely inducing arousal also decreased the duration of the interbout aroused (IBA) period, and the responsiveness to the induced arousal stimulus was influenced by torpor duration. The metabolic cost of natural versus induced arousal from torpor was also investigated. Metabolic activity was estimated through indirect calorimetry and assays of metabolites in blood plasma. Although initial rates of oxygen consumption were comparable for natural and induced arousal, initial rates of carbon dioxide production and respiratory quotient values were significantly reduced during induced arousal. Plasma lactate levels were significantly elevated during induced arousal whereas glucose and free fatty acids levels were similar. Previous work has indicated oxidative stress and elevated antioxidant defenses during hibernation. However, the effectiveness of these defenses has not been as well characterized. Indicators of oxidative damage to lipids and proteins in heart, liver, kidney, and brain tissues were measured to investigate potential oxidative damage to cellular macromolecules. Lipid peroxidation products and protein carbonyl levels were low in all tissues for both types of arousal. Thus, hibernators appear to be well protected against oxidative damage. Arousal was once regarded as a sole effort to rewarm as quickly as possible, thereby facilitating conservation of energy stores. However, data indicate that arousal is a more constrained process where animals regularly experience less than maximal rewarming rates. Further, prematurely inducing arousal alters key aspects of the rewarming process as well as metabolic activity. Considering these differences, I recommend that careful consideration be given to experimental design and data interpretation when arousing animals are utilized

Bone strength is maintained after 8 months of inactivity in hibernating golden-mantled ground squirrels, Spermophilus lateralis

Prolonged inactivity leads to disuse atrophy, a loss of muscle and bone mass. Hibernating mammals are inactive for 6–9 months per year but must return to full activity immediately after completing hibernation. This necessity for immediate recovery presents an intriguing conundrum, as many mammals require two to three times the period of inactivity to recover full bone strength. Therefore, if hibernators experience typical levels of bone disuse atrophy during hibernation, there would be inadequate time available to recover during the summer active season. We examined whether there were mechanical consequences as a result of the extended inactivity of hibernation. We dissected femur and tibia bones from squirrels in various stages of the annual hibernation cycle and measured the amount of force required to fracture these bones. Three groups were investigated; summer active animals were captured during the summer and immediately killed, animals in the 1 month detraining group were captured in the summer and killed following a 1-month period of restricted mobility, hibernating animals were killed after 8 months of inactivity. A three-point bend test was employed to measure the force required to break the bones. Apparent flexural strength and apparent flexural modulus (material stiffness) were calculated for femurs. There were no differences between groups for femur fracture force, tibia fracture force, or femur flexural strength. Femur flexural modulus was significantly less for the 1 month detraining group than for the hibernation and summer active groups. Thus, hibernators seem resistant to the deleterious effects of prolonged inactivity during the winter. However, they may be susceptible to immobilization-induced bone loss during the summer

Moderate Intensity Resistance Training Significantly Elevates Testosterone following Upper Body and Lower Body Bouts When Total Volume is Held Constant

Introduction: It is unknown whether resistance training intensity or total volume of work affects the acute testosterone response to a greater extent. Purpose: Therefore, the circulating testosterone response was investigated following four resistance training protocols where total volume of work was held constant: moderate intensity (70% 1RM) upper body (bench press, bent barbell row, and military press), moderate intensity lower body (squat and deadlift), high intensity (90% 1RM) upper body, high intensity lower body. Methods: Total volume of work performed by each participant between protocols was maintained by adjusting the number of sets and or repetitions performed. Ten healthy, resistance trained men volunteered, and performed exercise protocols on separate days in a counterbalanced order. Capillary blood was obtained via finger stick at baseline (pre), immediately following the exercise session (post), and 1h post for the determination of testosterone concentration. Data were analyzed using a factorial ANOVA and significance was accepted at p≤ 0.05. Results: Both moderate intensity resistance protocols (upper and lower body) significantly increased testosterone concentration (p=0.026, and p=0.024 respectively), whereas the high intensity protocols elevated testosterone but failed to achieve significance (upper p=0.272, lower p=0.658). No difference was noted in post session testosterone concentration between upper and lower body protocols for either moderate (p=0.248) or high intensity (p=0.990). Conclusion: This may be useful for novice resistance trained individuals because it provides evidence that moderate intensity is sufficient to increase testosterone compared to high intensity protocols that could be associated with a greater risk of injury.Keywords: hormone response, equal total work, high intensity protoco

Moderate Intensity Resistance Training Significantly Elevates Testosterone following Upper Body and Lower Body Bouts when Total Volume is held Constant

Introduction: It is unknown whether resistance training intensity or total volume of work affects the acute testosterone response to a greater extent. Purpose: Therefore, the circulating testosterone response was investigated following four resistance training protocols where total volume of work was held constant: moderate intensity (70% 1RM) upper body (bench press, bent barbell row, and military press), moderate intensity lower body (squat and deadlift), high intensity (90% 1RM) upper body, high intensity lower body. Methods: Total volume of work performed by each participant between protocols was maintained by adjusting the number of sets and or repetitions performed. Ten healthy, resistance trained men volunteered, and performed exercise protocols on separate days in a counterbalanced order. Capillary blood was obtained via finger stick at baseline (pre), immediately following the exercise session (post), and 1h post for the determination of testosterone concentration. Data were analyzed using a factorial ANOVA and significance was accepted at p≤ 0.05. Results:Both moderate intensity resistance protocols (upper and lower body) significantly increased testosterone concentration (p=0.026, and p=0.024 respectively), whereas the high intensity protocols elevated testosterone but failed to achieve significance (upper p=0.272, lower p=0.658). No difference was noted in post session testosterone concentration between upper and lower body protocols for either moderate (p=0.248) or high intensity (p=0.990). Conclusion: This may be useful for novice resistance trained individuals because it provides evidence that moderate intensity is sufficient to increase testosterone compared to high intensity protocols that could be associated with a greater risk of injury