3,455 research outputs found

    Survey, analysis and evaluation test on high voltage/current pulse transmission cables

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    A survey, analysis, and testing of available cable connector configurations were carried out in connection with transmission of high voltage/current to an exploding wire bridge. Transmission was desired at high efficiency with maximum cable flexibility, at minimum weight and size of the cable connector, with maximum cable length while maintaining applicable voltage/current pulse characteristics, and with due consideration to environmental parameters

    Teachers' classroom feedback: still trying to get it right

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    This article examines feedback traditionally given by teachers in schools. Such feedback tends to focus on children's acquisition and retrieval of externally prescribed knowledge which is then assessed against mandated tests. It suggests that, from a sociocultural learning perspective, feedback directed towards such objectives may limit children's social development. In this article, I draw on observation and interview data gathered from a group of 27 9- to 10-year olds in a UK primary school. These data illustrate the children's perceived need to conform to, rather than negotiate, the teacher's feedback comments. They highlight the children's sense that the teacher's feedback relates to school learning but not to their own interests. The article also includes alternative examples of feedback which draw on children's own inquiries and which relate to the social contexts within which, and for whom, they act. It concludes by suggesting that instead of looking for the right answer to the question of what makes teachers' feedback effective in our current classrooms, a more productive question might be how a negotiation can be opened up among teachers and learners themselves, about how teachers' feedback could support children's learning most appropriately

    Use of Simulation Methods of Wave Processes for Non-Destructive Testing of Concrete Products of Different Geometrical Size

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    Theoretical and experimental research of electrical responses under pulsed mechanical excitation of different size concrete products was carried out. Comparison of calculated and experimental data shows very close agreement. The obtained results will help to develop new opportunities to improve the method of non-destructive testing of concrete by creating a bank of calculated electrical responses from products of different geometrical arrangement and elastic response and using them as standard samples for defectiveness evaluation of products according to previously established criteria

    It’s the Combination: Scientific Data Review of the First Corn Silage to Bring Together Fiber and Starch Digestibility

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    This information was presented at the 2017 Cornell Nutrition Conference for Feed Manufacturers, organized by the Department of Animal Science In the College of Agriculture and Life Sciences at Cornell University. Softcover copies of the entire conference proceedings may be purchased at http://ansci.cals.cornell.edu/extension-outreach/adult-extension/dairy-management/order-proceedings-resources.A recent study compared a newly developed brown midrib 3 corn silage with floury endosperm to a conventional corn silage and a brown midrib 3 corn silage for high-producing Holstein cows. The combination of greater rumen fiber and starch fermentability of the new hybrid resulted in greater efficiency of solids-corrected milk production and milk nitrogen efficiency compared with the brown midrib and conventional hybrids

    Tourism policy and destination marketing in developing countries: the chain of influence

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    Tourism marketers including destination marketing organisations (DMOs) and international tour operators play a pivotal role in destination marketing, especially in creating destination images. These images, apparent in tourist brochures, are designed to influence tourist decision-making and behaviour. This paper proposes the concept of a “chain of influence” in destination marketing and image-making, suggesting that the content of marketing materials is influenced by the priorities of those who design these materials, e.g. tour operators and DMOs. A content analysis of 2,000 pictures from DMO and tour operator brochures revealed synergies and divergence between these marketers. The brochure content was then compared to the South African tourism policy, concluding that the dominant factor in the chain of influence in the South African context is in fact its organic image

    Magnetic phase diagram of cubic perovskites SrMn_1-xFe_xO_3

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    We combine the results of magnetic and transport measurements with Mossbauer spectroscopy and room-temperature diffraction data to construct the magnetic phase diagram of the new family of cubic perovskite manganites SrMn_1-xFe_xO_3. We have found antiferromagnetic ordering for lightly and heavily Fe-substituted material, while intermediate substitution leads to spin-glass behavior. Near the SrMn_0.5Fe_0.5O_3 composition these two types of ordering are found to coexist and affect one another. The spin glass behavior may be caused by competing ferro- and antiferromagnetic interactions among Mn^4+ and observed Fe^3+ and Fe^5+ ions.Comment: 8 pages, 10 figures, revtex, accepted to Phys. Rev.

    Gravitational Microlensing Evidence for a Planet Orbiting a Binary Star System

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    The study of extra-solar planetary systems has emerged as a new discipline of observational astronomy in the past few years with the discovery of a number of extra-solar planets. The properties of most of these extra-solar planets were not anticipated by theoretical work on the formation of planetary systems. Here we report observations and light curve modeling of gravitational microlensing event MACHO-97-BLG-41, which indicates that the lens system consists of a planet orbiting a binary star system. According to this model, the mass ratio of the binary star system is 3.8:1 and the stars are most likely to be a late K dwarf and an M dwarf with a separation of about 1.8 AU. A planet of about 3 Jupiter masses orbits this system at a distance of about 7 AU. If our interpretation of this light curve is correct, it represents the first discovery of a planet orbiting a binary star system and the first detection of a Jovian planet via the gravitational microlensing technique. It suggests that giant planets may be common in short period binary star systems.Comment: 11 pages, with 1 color and 2 b/w Figures included (published version

    Cymantrene–Triazole "Click" Products: Structural Characterization and Electrochemical Properties

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    We report the first known examples of triazole-derivatized cymantrene complexes (η5-[4-substituted triazol-1-yl]cyclopentadienyl)tricarbonylmanganese(I), obtained via a “click” chemical synthesis, bearing a phenyl, 3-aminophenyl, or 4-aminophenyl moiety at the 4-position of the triazole ring. Structural characterization data using multinuclear NMR, UV–vis, ATR-IR, and mass spectrometric methods are provided, as well as crystallographic data for (η5-[4-phenyltriazol-1-yl]cyclopentadienyl)tricarbonylmanganese(I) and (η5-[4-(3-aminophenyl)triazol-1-yl]cyclopentadienyl)tricarbonylmanganese(I). Cyclic voltammetric characterization of the redox behavior of each of the three cymantrene–triazole complexes is presented together with digital simulations, in situ infrared spectroelectrochemistry, and DFT calculations to extract the associated kinetic and thermodynamic parameters. The trypanocidal activity of each cymantrene–triazole complex is also examined, and these complexes are found to be more active than cymantrene alone

    Enhancing learning and assessment of pre-service teachers on practicum placements using mobile technologies with video capture

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    Across all educational jurisdictions, each year, large numbers of pre-service teachers are assessed for their suitability for teaching during their teacher education courses, in schools and institutions through practicum placements or workplace learning. Despite their widespread use, practicums can be notoriously variable and unreliable in terms of assessment (Rorrison, 2008) and in promoting professional learning (Grudnoff, 2011). The study reported through the publications explicit or referred to in this exegesis focused on the development of a mobile application (‘app’) to address the problems of assessment and professional growth. It was a specific response to the emerging use of mobile devices that utilise video capture, and their impact on assessing students in the practicum component of their training. It drew on existing knowledge of higher education assessments and teacher training assessments, including formative assessments and feedback, linked to the introduction of mobile devices with video capture capabilities. This study examined how mobile technologies, such as smartphones and tablet devices with multimedia capabilities, could address some of the problems faced by pre-service teacher students, their school-based supervisors and the university academics who manage the practicum assessment. The overarching research question of the study was: To what extent can disciplined and structured use of mobile technologies for practicums impact on pedagogy and assessment of professional experiences of pre-service teachers? The study employed a Participatory Action Learning Action Research (PALAR) methodology to address the extent to which disciplined and structured use of mobile technologies impacted on practicum feedback of professional learning experiences of pre-service teachers. The study entailed six participatory research cycles over a four-year period, each consisting of four main phases: planning, acting and observing, reflecting and replanning. A mixed methods approach was used within the observation phases of each cycle. Because of the cyclical features of action research, the study lent itself to publishing findings throughout the project, rather than a single thesis at conclusion. Thus, reports of the research following one or more cycles were published, and this document therefore, is an exegesis of the major papers that were published over the timeframe of the study. The exegesis seeks to unify the publications and provide common themes emerging from the research project. The findings from the several cycles showed that the introduction of mobile technologies had a major impact on the practices and outcomes of pre-service teachers’ practicum experiences. The inclusion of mobile devices with video capture positively impacted on the reflective practices of pre-service teachers as well as formative assessment and feedback for pre-service teachers by providing the opportunity for more detailed, ongoing analysis of pre-service teachers’ performances while on practicum. Findings from the school-based supervising teachers also confirmed the suitability of the ‘app’ for enhancing the practicum experience and its assessment. Further research is required to demonstrate the impact of the application on enhancing learning through the medium of curriculum standards in the school environment. In addition, there is a need to explore more broadly applied mobile feedback systems in the context of practicum assessments

    SEC Consequences of Corporate Acquisitions. Carl W. Schneider, ed.

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