15 research outputs found

    Caffeine Versus Methylphenidate and d-Amphetamine in Minimal Brain Dysfunction: A Double-Blind Comparison

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    The authors compared the efficacy of caffeine, methylphenidate, and d-amphetamine in children with minimal brain dysfunction using a double-blind crossover design. The slight improvement with caffeine was not significantly better than placebo. Both prescription drugs resulted in significant improvement and were significantly superior to caffeine. The authors suggest that the discrepancy between these results and an earlier, more optimistic report may stem from the use in this study of pure caffeine rather than whole coffee

    Fabrication and Testing of Durable Redundant and Fluted-Core Joints for Composite Sandwich Structures

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    The development of durable bonded joint technology for assembling composite structures is an essential component of future space technologies. While NASA is working toward providing an entirely new capability for human space exploration beyond low Earth orbit, the objective of this project is to design, fabricate, analyze, and test a NASA patented durable redundant joint (DRJ) and a NASA/Boeing co-designed fluted-core joint (FCJ). The potential applications include a wide range of sandwich structures for NASA's future launch vehicles. Three types of joints were studied -- splice joint (SJ, as baseline), DRJ, and FCJ. Tests included tension, after-impact tension, and compression. Teflon strips were used at the joint area to increase failure strength by shifting stress concentration to a less sensitive area. Test results were compared to those of pristine coupons fabricated utilizing the same methods. Tensile test results indicated that the DRJ design was stiffer, stronger, and more impact resistant than other designs. The drawbacks of the DRJ design were extra mass and complex fabrication processes. The FCJ was lighter than the DRJ but less impact resistant. With barely visible but detectable impact damages, all three joints showed no sign of tensile strength reduction. No compression test was conducted on any impact-damaged sample due to limited scope and resource. Failure modes and damage propagation were also studied to support progressive damage modeling of the SJ and the DRJ

    Gas emissions, minerals, and tars associated with three coal fires, Powder River Basin, USA.

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    Ground-based surveys of three coal fires and airborne surveys of two of the fires were conducted near Sheridan, Wyoming. The fires occur in natural outcrops and in abandoned mines, all containing Paleocene-age subbituminous coals. Diffuse (carbon dioxide (CO(2)) only) and vent (CO(2), carbon monoxide (CO), methane, hydrogen sulfide (H(2)S), and elemental mercury) emission estimates were made for each of the fires. Additionally, gas samples were collected for volatile organic compound (VOC) analysis and showed a large range in variation between vents. The fires produce locally dangerous levels of CO, CO(2), H(2)S, and benzene, among other gases. At one fire in an abandoned coal mine, trends in gas and tar composition followed a change in topography. Total CO(2) fluxes for the fires from airborne, ground-based, and rate of fire advancement estimates ranged from 0.9 to 780mg/s/m(2) and are comparable to other coal fires worldwide. Samples of tar and coal-fire minerals collected from the mouth of vents provided insight into the behavior and formation of the coal fires

    A short form of the Wechsler Intelligence Scale for Children-Revised

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    Study of Two Axisymmetric Inlets Designed for Mach 3.5

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    Performance Estimates for a Supersonic Axisymmetric Inlet System

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    Politicization, Bureaucratic Legalism, and Innovative Attitudes in the Public Sector

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    Previous studies have identified institutional, organizational, and individual factors that promote innovation in public organizations. Yet they have overlooked how the type of public administration—and the type of administrators—is associated with innovative attitudes. Using two large, unique comparative data sets on public bureaucracies and public managers, this article examines how bureaucratic politicization and legalistic features are associated with senior public managers’ attitudes toward innovation in 19 European countries. Results of multilevel analysis indicate that the bureaucratic politicization of an administration and the law background of public managers matter. Public managers working in politicized administrations and those whose education includes a law degree exhibit lower pro‐innovation attitudes (i.e., receptiveness to new ideas and creative solutions and change orientation).The politics and administration of institutional chang
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