1,824 research outputs found

    Eclectic styles and classical performance: Motivation and self-efficacy belief at two summer music camps

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    String teachers and scholars have suggested that classically-trained students may be motivated to engage in eclectic (e.g., rock, pop, jazz, groove, folk) styles. However, we do not fully understand the ways in which students’ motivations to engage in new musics might be influenced by their perceptions of competence in those styles. In this mixed-method study we draw upon quantitative, qualitative, and arts-based data from 120 middle and high school students at two camps (one emphasizing classical music, the other emphasizing eclectic styles), to explore various ways in which students develop self-efficacy beliefs and motivation to perform in a variety of musical approaches. According to analysis of all data, students at both camps generally expressed having positive musical and social experiences. Negative experiences, while less common, stemmed from confusion or frustration with music learning, boredom with music that was too easy or not interesting, and competitive comparison with others. Based on findings from qualitative and arts-based data, we suggest that these students may have benefitted from additional teacher support when encountering new musical technique

    Thermoeconomic analysis of residential rooftop photovoltaic systems with integrated energy storage and resulting impacts on electrical distribution networks

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    journal articleThis paper investigates residential rooftop photovoltaic (PV) systems for long-term thermoeconomic benefits from PV homeowners' perspectives and for impacts on the electrical distribution network from grid operators' perspectives. The costs of generating electricity from grid-connected PV systems are studied with and without energy storage at the PV homeowners' sites. Three selling scenarios for excess PV energy conversion are considered: net metering, wholesale pricing, and no payback. PV systems in Utah are utilized as case studies in this analysis. The presence of PV systems gives homeowners economic benefits such as reduced annual electricity bills. However, the levelized costs of electricity are considerably higher than the weighted electricity price in Utah. Currently, the addition of energy storage only benefits customers in Utah under the no payback policy. The impacts of PV systems toward electrical distribution networks are then studied on a distribution test system. Excess PV generation from residential PV systems causes voltage rise in the electrical distribution network. The results from this paper can educate consumers about the lifetime benefit of integrating solar energy into their homes. For grid operators, residential PV systems with energy storage can reduce the negative impacts on the grid compared with high PV penetration alone

    Incorporating performance-based global sensitivity and uncertainty analysis into LCOE calculations for emerging renewable energy technologies

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    pre-printAssessing system costs for power generation is essential for evaluating the economical aspect of energy resources. This paper examines traditional and renewable energy resources under uncertainty and variability of input variables. The levelized cost of electricity (LCOE) of each technology is computed using a global sensitivity analysis. A Monte Carlo approach is utilized to study the thermoeconomics of a variety of power generation methods in the United States: fossil fuel-based, nuclear, developed renewable, and emerging renewable energy resources. The results of this study demonstrate how uncertainties in input data can significantly influence the LCOE values. Power generation from well-developed energy technologies exhibit less variability in LCOE due to established capital costs, operating and maintenance costs, and power generation. On the contrary, emerging renewable energy technologies are subject to high uncertainties in both technical and economic performance, as expected for technologies in early stages of development. A scenario with carbon pricing in power generation is also carried out in the paper. The presence of carbon pricing significantly increases the LCOEs of fossil fuel technologies, and LCOEs of other technologies also experience significant changes when life-cycle carbon assessments are considered. Several cost reduction opportunities are discussed to guide the development of future energy conversion, especially from emerging renewable energy resources

    Background Studies for the Neutral Current Detector Array in the Sudbury Neutrino Observatory

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    An array of 3He-filled proportional counters will be used in the Sudbury Neutrino Observatory to measure the neutral-current interaction of neutrinos and deuterium. We describe the backgrounds to this detection method.Comment: Accepted for publication in the proceedings of TAUP99. 2 page

    Supporting 'design for reuse' with modular design

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    Engineering design reuse refers to the utilization of any knowledge gained from the design activity to support future design. As such, engineering design reuse approaches are concerned with the support, exploration, and enhancement of design knowledge prior, during, and after a design activity. Modular design is a product structuring principle whereby products are developed with distinct modules for rapid product development, efficient upgrades, and possible reuse (of the physical modules). The benefits of modular design center on a greater capacity for structuring component parts to better manage the relation between market requirements and the designed product. This study explores the capabilities of modular design principles to provide improved support for the engineering design reuse concept. The correlations between modular design and 'reuse' are highlighted, with the aim of identifying its potential to aid the little-supported process of design for reuse. In fulfilment of this objective the authors not only identify the requirements of design for reuse, but also propose how modular design principles can be extended to support design for reuse

    General mutation databases : analysis and review

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    Databases of mutations causing Mendelian disease play a crucial role in research, diagnostic and genetic health care and can play a role in life and death decisions. These databases are thus heavily used, but only gene or locus specific databases have been previously reviewed for completeness, accuracy, currency and utility. We have performed a review of the various general mutation databases that derive their data from the published literature and locus specific databases. Only two&mdash;the Human Gene Mutation Database (HGMD) and Online Mendelian Inheritance in Man (OMIM)&mdash;had useful numbers of mutations. Comparison of a number of characteristics of these databases indicated substantial inconsistencies between the two databases that included absent genes and missing mutations. This situation strengthens the case for gene specific curation of mutations and the need for an overall plan for collection, curation, storage and release of mutation data.<br /

    Quantum wave equation of photon

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    In this paper, we give the quantum wave equations of single photon when it is in the free or medium space. With these equations, we can study light interference and diffraction with quantum approach. Otherwise, they can be applied in quantum optics and photonic crystal.Comment: 8 pages, 0 figure

    Understanding African American youth and adult perspectives on sex education in rural North Carolina

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    African American youth in the US rural South are at elevated risk for poor sexual health outcomes, including sexually transmitted infections and teenage pregnancy. Historically, the southeastern USA has lagged behind in providing comprehensive sexuality-based education in secondary school, which may contribute to poor reproductive and sexual health outcomes. This study aimed to understand the perspectives of African American youth and adults on comprehensive sexuality-based education in rural North Carolina. Twenty-four individuals (12 youth and 12 adults) participated in both semi-structured interviews and small discussion groups. Data were analysed and coded using inductive and deductive approaches to thematic analysis. Results indicated that comprehensive sexuality-based education was viewed as highly desirable; however, current efforts were seen as insufficient. While both young people and adults agreed that abstinence was the most desirable path for youth, participants also acknowledged young people’s autonomy in engaging in sexual activity and suggested that comprehensive sexuality-based education was needed to protect against unintended consequences. The findings of this study have practical implications for addressing challenges associated with providing sexuality-based education to African American youth in rural communities and offers suggestions regarding directions for future research

    Positivity constraints for lepton polarization in neutrino deep inelastic scattering

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    We consider the spin polarization of leptons produced in neutrino and antineutrino nucleon deep inelastic scattering, via charged currents, and we study the positivity constraints on the spin components in a model independent way. These results are very important, in particular in the case of τ±\tau^{\pm} leptons, because the polarization information is crucial in all future neutrino oscillation experiments.Comment: 14 pages, 4 figure

    Polymer Light‐Emitting Transistors With Charge‐Carrier Mobilities Exceeding 1 cm2 V−1 s−1

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    The vast majority of conjugated polymer-based light emitting field-effect transistors (LEFETs) are characterized by low charge carrier mobilities typically in the range 10-5 to 10-3 cm2 V-1 s-1 range. Fast carrier transport is a highly desirable characteristic for high frequency LEFET operation and, potentially, for use in electrically-pumped lasers. Unfortunately, high mobility organic semiconductors are often characterised by strong intermolecular π-π interactions that reduce luminescence. Development of new materials and/or device concepts that overcome this hurdle are therefore required. We report single organic semiconductor layer, light-emitting transistors that combine the highest hole mobilities reported to date for any polymer-based LEFET, with encouraging light emission characteristics. We achieve this in a single polymer layer LEFET, which was further enhanced through the use of a small-molecule/conjugated polymer blend system that possesses a film microstructure which supports enhanced charge carrier mobility (3.2 cm2 V-1 s-1) and promising light emission characteristics (1600 cd m-2) as compared to polymer-only based LEFETs. This simple approach represents an attractive strategy to further advance the performance of solution-processed LEFETs
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