The Effect of Energy-Matched Exercise Intensity on Brain-Derived Neurotrophic Factor and Motor Learning

Brain plasticity is important to motor learning, and is a critical component of motor rehabilitation. Exercise prior to motor training may facilitate plasticity by increasing brain-derived neurotrophic factor (BDNF). However, many studies that have investigated exercise-enhanced plasticity have assessed motor skill performance on tasks involving single finger button presses or small movements of a joystick, results that may not relate to more complex, real-world movements. Additionally, while high-intensity exercise has been shown to benefit motor learning, the effects of low-intensity exercise have yet to be fully investigated. A bout of low-intensity exercise, when completed at an energy expenditure that is equivalent to that of a high-intensity exercise bout, may also benefit learning and might be particularly relevant to individuals with neurological disorders who may only be capable of achieving low-levels of physical activity. Therefore, our first aim was to develop a motor learning task that involved 3-dimensional (3D) reach movements. Our second aim was to investigate the effects of exercise intensity on motor learning of the same task. In Study 1, we developed a motor learning task in a virtual environment that involved 3D reach movements to sequentially presented targets. With this task, we produced results similar to those traditionally observed in the motor learning literature; individuals improved with practice (p \u3c 0.001) and performance was maintained at retention (p = 0.386). Since our task involved 3D reach movements, results from studies utilizing this task may be more relatable to real-world movements. In Study 2, we used the 3D reach task to investigate the effects of exercise intensity on motor learning. We compared performance on the 3D reach task and the BDNF response to exercise between a rest group, a high-intensity exercise group, and a low-intensity exercise group. Both exercise groups expended 200 kilocalories of energy. Overall improvement on the motor task, indicated by a reduced response time, did not differ by group. However, exercise at both a high and low-intensity altered the kinematic profile used to improve performance over time. The rest group improved in the spatial domain of performance more than the exercise groups, while both high and low-intensity exercise groups improved more in the temporal domain of performance. Therefore, exercise at a specific energy expenditure, whether at a low or high-intensity, may facilitate the temporal components of motor performance. A significant rise in BDNF was not observed after exercise in either exercise group. Furthermore, the high variability observed in the exercise-related BDNF response was not related to BDNF genotype. However, BDNF genotype did have an effect on performance of the 3D reach task. Individuals with the BDNF polymorphism had faster response times throughout task practice (p = 0.002). Future work is needed to fully understand the effects of the polymorphism on motor performance and learning. Our investigation revealed that energy expenditure may be more important than exercise intensity for inducing an exercise-related effect in the kinematics of reach behavior. In addition, exercise may influence motor behavior through neural mechanisms other than BDNF

Continued Progress: Promising Evidence on Personalized Learning

The findings are grouped into four sections. The first section on student achievement finds that there were positive effects on student mathematics and reading performance and that the lowest-performing students made substantial gains relative to their peers. The second section on implementation and the perceptions of stakeholders finds that adoption of personalized learning practices varied considerably. Personalized learning practices that are direct extensions of current practice were more common, but implementation of some of the more challenging personalized learning strategies was less common. The third section relates implementation features to outcomes and identifies three elements of personalized learning that were being implemented in tandem in the schools with the largest achievement effects. Finally, the fourth section compares teachers' and students' survey responses to a national sample and finds some differences, such as teachers' greater use of practices that support competency-based learning and greater use of technology for personalization in the schools in this study with implementation data

Flux domes in superconducting films without edges

Domelike magnetic-flux-density distributions previously have been observed experimentally and analyzed theoretically in superconducting films with edges, such as in strips and thin plates. Such flux domes have been explained as arising from a combination of strong geometric barriers and weak bulk pinning. In this paper we predict that, even in films with bulk pinning, flux domes also occur when vortices and antivortices are produced far from the film edges underneath current-carrying wires, coils, or permanent magnets placed above the film. Vortex-antivortex pairs penetrating through the film are generated when the magnetic field parallel to the surface exceeds H_{c1}+K_c, where H_{c1} is the lower critical field and K_c = j_c d is the critical sheet-current density (the product of the bulk critical current density j_c and the film thickness d). The vortices and antivortices move in opposite directions to locations where they join others to create separated vortex and antivortex flux domes. We consider a simple arrangement of a pair of current-carrying wires carrying current I_0 in opposite directions and calculate the magnetic-field and current-density distributions as a function of I_0 both in the bulk-pinning-free case (K_c = 0) and in the presence of bulk pinning, characterized by a field-independent critical sheet-current density (K_c > 0).Comment: 15 pages, 23 figure

Parametric vision simulation study, part 2 Final report

Effects of landing site redesignation on visibility during manned lunar landin

Drug interactions may be important risk factors for methotrexate neurotoxicity, particularly in pediatric leukemia patients

Purpose: Methotrexate administration is associated with frequent adverse neurological events during treatment for childhood acute lymphoblastic leukemia. Here, we present evidence to support the role of common drug interactions and low vitamin B12 levels in potentiating methotrexate neurotoxicity. Methods: We review the published evidence and highlight key potential drug interactions as well as present clinical evidence of severe methotrexate neurotoxicity in conjunction with nitrous oxide anesthesia and measurements of vitamin B12 levels among pediatric leukemia patients during therapy. Results: We describe a very plausible mechanism for methotrexate neurotoxicity in pediatric leukemia patients involving reduction in methionine and consequential disruption of myelin production. We provide evidence that a number of commonly prescribed drugs in pediatric leukemia management interact with the same folate biosynthetic pathways and/or reduce functional vitamin B12 levels and hence are likely to increase the toxicity of methotrexate in these patients. We also present a brief case study supporting out hypothesis that nitrous oxide contributes to methotrexate neurotoxicity and a nutritional study, showing that patients. Conclusions: Use of nitrous oxide in pediatric leukemia patients at the same time as methotrexate use should be avoided especially as many suitable alternative anesthetic agents exist. Clinicians should consider monitoring levels of vitamin B12 in patients suspected of having methotrexate- induced neurotoxic effects

Reply: Methotrexate neurotoxicity due to drug interactions: an inadequate folinic acid effect

No abstract available

Translating Standardized Effects of Education Programs Into More Interpretable Metrics

Evaluators report effects of education initiatives as standardized effect sizes, a scale that has merits but obscures interpretation of the effects’ practical importance. Consequently, educators and policymakers seek more readily interpretable translations of evaluation results. One popular metric is the number of years of learning necessary to induce the effect. We compare years of learning to three other translation options: benchmarking against other effect sizes, converting to percentile growth, and estimating the probability of scoring above a proficiency threshold. After enumerating the desirable properties of translations, we examine each option’s strengths and weaknesses. We conclude that years of learning performs worst, and percentile gains performs best, making it our recommended choice for more interpretable translations of standardized effects

Note: Utilizing Pb(Zr 0.95Ti 0.05)O₃ Ferroelectric Ceramics to Scale Down Autonomous Explosive-Driven Shock-Wave Ferroelectric Generators

Further miniaturization of recently designed autonomous ferroelectric generators (FEGs) S. I. Shkuratov, J. Baird, and E. F. Talantsev, Rev. Sci. Instrum. 82, 086107 (2011), which are based on the effect of explosive-shock-wave depolarization of poled ferroelectrics is achieved. The key miniaturization factor was the utilization of high-energy density Pb(Zr0.95Ti0.05)O3 (PZT 955) ferroelectric ceramics as energy-carrying elements of FEGs instead of the previously used Pb(Zr0.52Ti0.48)O3 (PZT 5248). A series of experiments demonstrated that FEGs based on smaller PZT 955 ferroelectric elements are capable of producing the same output voltage as those based on PZT 5248 elements twice as large. It follows from the experimental results that the FEG output voltage is directly proportional to the thickness of PZT 955 samples. A comparison of the operation of FEGs based on PZT 955 and on PZT 5248 ferroelectrics is presented