Laboratories of Reform: Virtual High Schools and Innovation in Public Education

Virtual schools are growing rapidly, serving over 700,000 students in the 2005-06 school year. But these schools are proving to be more than just another delivery system for students; they are bringing about reforms that have long eluded traditional public schools

Beyond the Bubble: Technology and the Future of Student Assessment

Provides an overview of information technology's potential to enable better assessments of student achievement. Outlines promising models for testing complex skills, cognition, and learning and for utilizing such assessments to improve instruction

The influence of snow depth and hardness on winter habitat selection by caribou on the southwest coast of Newfoundland

LaPoile Herd caribou winter in the coastal margin of their range in southwestern Newfoundland. Reduced snow depths near the coast (0-20 km inland), as a result of moderated winter temperatures and low elevations, appear to provide more favourable foraging conditions than do areas further inland. In the latter areas greatly increased snow depth and hardness combine to create very extreme winter conditions and these areas are avoided by caribou throughout the winter period

A Multimodal Instant Messaging System using XML-Based Protocols

Instant Messaging is traditionally a text only affair. However, there are instances when it would be useful to bridge to other types of media, like speech. The SoftBridge is an application framework that enables this kind of communications bridging using instant messages. Its use of protocols like the Jabber Instant Messaging Protocol and the Simple Object Access Protocol makes it simple, open and extensible. It also allows bridging to non IP communications infrastructure, like the telephone network. We describe the design and architecture of the system, protocol and extensibility mechanism. Finally we describe our experimental methodology and discuss the results of two sets of experiments: those involving a Deaf User, and those involving a set of Simulated Users

Study of a Tricarbide Grooved Ring Fuel Element for Nuclear Thermal Propulsion

Deep space exploration, especially that of Mars, is on the horizon as the next big challenge for space exploration. Nuclear propulsion, through which high thrust and efficiency can be achieved, is a promising option for decreasing the cost and logistics of such a mission. Work on nuclear thermal engines goes back to the days of the NERVA program. Currently, nuclear thermal propulsion is under development again in various forms to provide a superior propulsion system for deep space exploration. The authors have been working to develop a concept nuclear thermal engine that uses a grooved ring fuel element as an alternative to the traditional hexagonal rod design. The authors are also studying the use of carbide fuels. The concept was developed in order to increase surface area and heat transfer to the propellant. The use of carbides would also raise the operating temperature of the reactor. It is hoped that this could lead to a higher thrust to weight nuclear thermal engine. This paper describes the modeling of neutronics, heat transfer, and fluid dynamics of this alternative nuclear fuel element geometry. Fabrication experiments of grooved rings from carbide refractory metals are also presented along with material characterization and interactions with a hot hydrogen environment. Results of experiments and associated analysis are discussed. The authors demonstrated success in reaching desired densities with some success in material distribution and reaching a solid solution. Future work is needed to improve distribution of material, minimize oxidation during the milling process, and define a fabrication process that will serve for constructing grooved ring fuel rods for large system tests

Study of a Tricarbide Grooved Ring Fuel Element for Nuclear Thermal Propulsion

Deep space exploration, especially that of Mars, is on the horizon as the next big challenge for space exploration. Nuclear propulsion, through which high thrust and efficiency can be achieved, is a promising option for decreasing the cost and logistics of such a mission. Work on nu- clear thermal engines goes back to the days of the NERVA program. Currently, nuclear thermal propulsion is under development again in various forms to provide a superior propulsion system for deep space exploration. The authors have been working to develop a concept nuclear thermal engine that uses a grooved ring fuel element as an alternative to the traditional hexagonal rod design. The authors are also studying the use of carbide fuels. The concept was developed in order to increase surface area and heat transfer to the propellant. The use of carbides would also raise the operating temperature of the reactor. It is hoped that this could lead to a higher thrust to weight nuclear thermal engine. This paper describes the modeling of neutronics, heat transfer, and fluid dynamics of this alternative nuclear fuel element geometry. Fabrication experiments of grooved rings from carbide refractory metals are also presented along with material characterization and interactions with a hot hydrogen environment. Results of experiments and associated analysis are desired densities with some success in material distribution and reaching a solid solution. Future work is needed to improve distribution of material, minimize oxidation during the milling process, and de ne a fabrication process that will serve for constructing grooved ring fuel rods for large system tests

Neuromotor control during stair ambulation in individuals with patellofemoral osteoarthritis compared to asymptomatic controls

Patellofemoral OA is characterized by PF pain during activities that load a flexed knee. Stair stepping ability is frequently impaired, yet little is known of the muscular recruitment strategies utilized during this task. Altered recruitment strategies may provide targets for clinical interventions. We aimed to determine if people with PFOA ascend and descend stairs with different muscular recruitment strategies compared to similar aged healthy individuals.Twenty-two people with PFOA and 20 controls were recruited. Electromyographic recordings from gluteus maximus and medius, medial and lateral hamstrings, vastus medialis and lateralis, medial and lateral gastrocnemius and soleus were acquired during stair ascent and descent. Force plate data was acquired to determine timing of foot placements and characterize dynamic stability.Seventeen people with PFOA (59 ± 10 years, 73 ± 13 kg, 167 ± 9 cm) and 15 controls (57 ± 10 years, 73 ± 16 kg, 171 ± 11 cm) had complete data. People with PFOA demonstrated: longer vastii activation duration during descent (lateralis: p = 0.01; medialis: p = 0.02); earlier onset of vastus lateralis for ascent (p