1,487 research outputs found

    Energy Data Sheets

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    Cliff Day, who compiled the Energy Data Sheets, first became interested in teaching about alternative energy sources when he was at Glen Eyre School, Southampton. He developed a special interest in solar energy and many of his pupils were caught up in project work which was entered successfully in local competitions and found an important place in exhibitions of school work.His development work soon became well known to local teachers and to the Department of Education at the University of Southampton where, in 1978, he took up a Hartley Research Studentship, for two years full-time, to refine and develop the materials already available and to extend his study to other sources of energy

    Chemistry between the stars

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    A unit is presented for the secondary school teacher of physics, chemistry, astronomy, or earth sciences. Included are a list of reference materials, teaching aids, and projects. Discussion questions and a glossary are also provided. Concepts developed are: the nature of interstellar space, spectroscopy, molecular signals from space and interstellar molecules and other areas of astronomy

    Tunable lasers for water vapor measurements and other lidar applications

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    A tunable dye laser suitable for differential absorption (DIAL) measurements of water vapor in the troposphere was constructed. A multi-pass absorption cell for calibration was also constructed for use in atmospheric DIAL measurements of water vapor

    Spacelab experiment definition study on phase transition and critical phenomena in fluids: Interim report on experimental justification

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    Pure fluids and fluid mixtures near critical points are identified and are related to the progress of several disciplines. Consideration is given to thermodynamic properties, transport properties, and the complex nonlinear phenomena which occur when fluids undergo phase transitions in the critical region. The distinction is made between practical limits which may be extended by advances in technology and intrinsic ones which arise from the modification of fluid properties by the earth's gravitational field. The kinds of experiments near critical points which could best exploit the low gravity environment of an orbiting laboratory are identified. These include studies of the index of refraction, constant volume specific heat, and phase separation

    Physical therapy and deep brain stimulation in Parkinson’s Disease: Protocol for a pilot randomized controlled trial

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    Abstract Background Subthalamic nucleus deep brain stimulation (STN-DBS) reduces tremor, muscle stiffness, and bradykinesia in people with Parkinson’s Disease (PD). Walking speed, known to be reduced in PD, typically improves after surgery; however, other important aspects of gait may not improve. Furthermore, balance may worsen and falls may increase after STN-DBS. Thus, interventions to improve balance and gait could reduce morbidity and improve quality of life following STN-DBS. Physical therapy (PT) effectively improves balance and gait in people with PD, but studies on the effects of PT have not been extended to those treated with STN-DBS. As such, the efficacy, safety, and feasibility of PT in this population remain to be determined. The purpose of this pilot study is to address these unmet needs. We hypothesize that PT designed to target balance and gait impairment will be effective, safe, and feasible in this population. Methods/design Participants with PD treated with STN-DBS will be randomly assigned to either a PT or control group. Participants assigned to PT will complete an 8-week, twice-weekly PT program consisting of exercises designed to improve balance and gait. Control group participants will receive the current standard of care following STN-DBS, which does not include prescription of PT. The primary aim is to assess preliminary efficacy of PT on balance (Balance Evaluation Systems Test). A secondary aim is to assess efficacy of PT on gait (GAITRite instrumented walkway). Participants will be assessed OFF medication/OFF stimulation and ON medication/ON stimulation at baseline and at 8 and 12 weeks after baseline. Adverse events will be measured over the duration of the study, and adherence to PT will be measured to determine feasibility. Discussion To our knowledge, this will be the first study to explore the preliminary efficacy, safety, and feasibility of PT for individuals with PD with STN-DBS. If the study suggests potential efficacy, then this would justify larger trials to test effectiveness and safety of PT for those with PD with STN-DBS. Trial registration NCT03181282 (clinicaltrials.gov). Registered on 7 June 2017

    Isotopic fractionation during soil uptake of atmospheric hydrogen

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    Soil uptake of atmospheric hydrogen (H<sub>2</sub>) and the associated hydrogen isotope effect were studied using soil chambers in a Western Washington second-growth coniferous forest. Chamber studies were conducted during both winter and summer seasons to account for large natural variability in soil moisture content (4–50%) and temperature (6–22 °C). H<sub>2</sub> deposition velocities were found to range from 0.01–0.06 cm s<sup>−1</sup> with an average of 0.033 ± 0.008 cm s<sup>−1</sup> (95% confidence interval). Consistent with prior studies, deposition velocities were correlated with soil moisture below 20% soil moisture content during the summer season. During winter, there was considerable variability observed in deposition velocity that was not closely related to soil moisture. The hydrogen kinetic isotope effect with H<sub>2</sub> uptake was found to range from −24‰ to −109‰. Aggregate analysis of experimental data results in an average KIE of −57 ± 5‰ (95% CI). Some of the variability in KIE can be explained by larger isotope effects at lower (<10%) and higher (>30%) soil moisture contents. The measured KIE was also found to be correlated with deposition velocity, with smaller isotope effects occurring at higher deposition velocities. If correct, these findings will have an impact on the interpretation of atmospheric measurements and modeling of δD of H<sub>2</sub>

    Raman Scattering Spectra of Elementary Electronic Excitations in Coupled Double-Quantum Well Structures

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    Using the time-dependent-local-density-approximation (TDLDA) within a self-consistent linear response theory, we calculate the elementary excitation energies and the associated inelastic light-scattering spectra of a strongly coupled two-component plasma in a double-quantum well system with electron occupation of symmetric and antisymmetric subbands. We find, consistent with the results of a recent experimental Raman scattering study, that the intersubband spin density excitations tend to merge with the single particle excitations (i.e. the excitonic shift decreases monotonically) as the Fermi energy increases beyond the symmetric-antisymmetric energy gap △SAS\bigtriangleup_{SAS}. However, our TDLDA calculation does not show the abrupt suppresion of the excitonic shift seen experimentally at a finite value of the subband occupancy parameter η≡△SAS/EF\eta \equiv \bigtriangleup_{\text{SAS}} / E_{\text{F}}.Comment: 9 pages, RevTeX, 5 figures available upon request, PIT-SDS-00

    Stimulated and spontaneous optical generation of electron spin coherence in charged GaAs quantum dots

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    We report on the coherent optical excitation of electron spin polarization in the ground state of charged GaAs quantum dots via an intermediate charged exciton (trion) state. Coherent optical fields are used for the creation and detection of the Raman spin coherence between the spin ground states of the charged quantum dot. The measured spin decoherence time, which is likely limited by the nature of the spin ensemble, approaches 10 ns at zero field. We also show that the Raman spin coherence in the quantum beats is caused not only by the usual stimulated Raman interaction but also by simultaneous spontaneous radiative decay of either excited trion state to a coherent combination of the two spin states.Comment: 4 pages, 3 figures. Minor modification
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