An Assessment of Influences Which Affect Teachers’ Use of Technology

Current literature is plentiful on computer-based technology’s positive influence on students. There are only a few studies that have considered the influence that technology has on teachers. This is a study about influences, which affect teachers’ use of technology. It is based on inconsistencies in previous studies, areas not addressed in previous surveys, and the dramatic changes in technology and Internet access using Web browsers since the previous surveys on technology were conducted. As new technologies make their way into instructional settings, effects of teachers’ use of technology can be dynamic. This study examined particular areas of teachers’ use of technology. The scope of this study does not provide exhaustive information, but as it unravels, its beginnings create a foundation to understand the role of technology in teaching and learning

Objective Assessment Method for RNAV STAR Adherence

Flight crews and air traffic controllers have reported many safety concerns regarding area navigation standard terminal arrival routes (RNAV STARs). Specifically, optimized profile descents (OPDs). However, our information sources to quantify these issues are limited to subjective reporting and time consuming case-by-case investigations. This work is a preliminary study into the objective performance of instrument procedures and provides a framework to track procedural concepts and assess design specifications. We created a tool and analysis methods for gauging aircraft adherence as it relates to RNAV STARs. This information is vital for comprehensive understanding of how our air traffic behaves. In this study, we mined the performance of 24 major US airports over the preceding three years. Overlaying 4D radar track data onto RNAV STAR routes provided a comparison between aircraft flight paths and the waypoint positions and altitude restrictions. NASA Ames Supercomputing resources were utilized to perform the data mining and processing. We assessed STARs by lateral transition path (full-lateral), vertical restrictions (full-lateral/full-vertical), and skipped waypoints (skips). In addition, we graphed frequencies of aircraft altitudes relative to the altitude restrictions. Full-lateral adherence was always greater than Full-lateral/ full- vertical, as it is a subset, but the difference between the rates was not consistent. Full-lateral/full-vertical adherence medians of the 2016 procedures ranged from 0% in KDEN (Denver) to 21% in KMEM (Memphis). Waypoint skips ranged from 0% to nearly 100% for specific waypoints. Altitudes restrictions were sometimes missed by systematic amounts in 1,000 ft. increments from the restriction, creating multi-modal distributions. Other times, altitude misses looked to be more normally distributed around the restriction. This tool may aid in providing acceptability metrics as well as risk assessment information

Observing the End of Cold Flow Accretion using Halo Absorption Systems

We use cosmological SPH simulations to study the cool, accreted gas in two Milky Way-size galaxies through cosmic time to z=0. We find that gas from mergers and cold flow accretion results in significant amounts of cool gas in galaxy halos. This cool circum-galactic component drops precipitously once the galaxies cross the critical mass to form stable shocks, Mvir = Msh ~ 10^12 Msun. Before reaching Msh, the galaxies experience cold mode accretion (T<10^5 K) and show moderately high covering fractions in accreted gas: f_c ~ 30-50% for R10^16 cm^-2. These values are considerably lower than observed covering fractions, suggesting that outflowing gas (not included here) is important in simulating galaxies with realistic gaseous halos. Within ~500 Myr of crossing the Msh threshold, each galaxy transitions to hot mode gas accretion, and f_c drops to ~5%. The sharp transition in covering fraction is primarily a function of halo mass, not redshift. This signature should be detectable in absorption system studies that target galaxies of varying host mass, and may provide a direct observational tracer of the transition from cold flow accretion to hot mode accretion in galaxies.Comment: 6 pages, 2 figures. Minor changes to match published version (results unchanged

Stochastic Optimization of Power System Dynamics for Grid Resilience

When faced with uncertainty regarding potential failure contingencies, prioritizing system resiliency through optimal control of exciter reference voltage and mechanical torque can be arduous due to the scope of potential failure contingencies. Optimal control schemes can be generated through a two-stage stochastic optimization model by anticipating a set of contingencies with associated probabilities of occurrence, followed by the optimal recourse action once the contingency has been realized. The first stage, common across all contingency scenarios, co-optimally positions the grid for the set of possible contingencies. The second stage dynamically assesses the impact of each contingency and allows for emergency control response. By unifying the optimal control scheme prior and post the failure contingency, a singular policy can be constructed to maximize system resiliency

Microscopy of Abrasive-Planed and Knife-Planed Surfaces in Wood-Adhesive Bonds

Fluorescence microscopy (FM) disclosed no differences in wood cell structure between abrasive-and knife-planed Douglas-fir joints under constant conditions. However, after a one-cycle soak-dry exposure, formation of checks along the rays were visible in both abrasive- and knife-planed samples by fluorescence microscopy. For this same exposure, scanning electron microscopy revealed many radial cracks in the S2 layer and ruptures between the S1 and S2 layers in abrasive-planed samples. Knife-planed samples had few ruptures between the S1 and S2 layers and very few cracks in the S2 layer.Previous work showed that, although knife planing gave much smoother surfaces at the cellular level than did abrasive planing, both surfaces resulted in high strength bonds. When those bonded samples were subjected to a soak-dry treatment, however, strength of abrasive-planed samples was much lower than that of knife-planed samples.The substantially intact S2 layers in knife-planed samples, as revealed here, apparently retain considerable strength, while rupturing and cracking in the abrasive-planed samples explain the loss of bond quality reported in earlier work

Nonmuscle Myosin II helps regulate synaptic vesicle mobility at the Drosophila neuromuscular junction

<p>Abstract</p> <p>Background</p> <p>Although the mechanistic details of the vesicle transport process from the cell body to the nerve terminal are well described, the mechanisms underlying vesicle traffic within nerve terminal boutons is relatively unknown. The actin cytoskeleton has been implicated but exactly how actin or actin-binding proteins participate in vesicle movement is not clear.</p> <p>Results</p> <p>In the present study we have identified Nonmuscle Myosin II as a candidate molecule important for synaptic vesicle traffic within <it>Drosophila </it>larval neuromuscular boutons. Nonmuscle Myosin II was found to be localized at the <it>Drosophila </it>larval neuromuscular junction; genetics and pharmacology combined with the time-lapse imaging technique FRAP were used to reveal a contribution of Nonmuscle Myosin II to synaptic vesicle movement. FRAP analysis showed that vesicle dynamics were highly dependent on the expression level of Nonmuscle Myosin II.</p> <p>Conclusion</p> <p>Our results provide evidence that Nonmuscle Myosin II is present presynaptically, is important for synaptic vesicle mobility and suggests a role for Nonmuscle Myosin II in shuttling vesicles at the <it>Drosophila </it>neuromuscular junction. This work begins to reveal the process by which synaptic vesicles traverse within the bouton.</p

Python Scripting in the Nengo Simulator

Nengo (http://nengo.ca) is an open-source neural simulator that has been greatly enhanced by the recent addition of a Python script interface. Nengo provides a wide range of features that are useful for physiological simulations, including unique features that facilitate development of population-coding models using the neural engineering framework (NEF). This framework uses information theory, signal processing, and control theory to formalize the development of large-scale neural circuit models. Notably, it can also be used to determine the synaptic weights that underlie observed network dynamics and transformations of represented variables. Nengo provides rich NEF support, and includes customizable models of spike generation, muscle dynamics, synaptic plasticity, and synaptic integration, as well as an intuitive graphical user interface. All aspects of Nengo models are accessible via the Python interface, allowing for programmatic creation of models, inspection and modification of neural parameters, and automation of model evaluation. Since Nengo combines Python and Java, it can also be integrated with any existing Java or 100% Python code libraries. Current work includes connecting neural models in Nengo with existing symbolic cognitive models, creating hybrid systems that combine detailed neural models of specific brain regions with higher-level models of remaining brain areas. Such hybrid models can provide (1) more realistic boundary conditions for the neural components, and (2) more realistic sub-components for the larger cognitive models