21,894 research outputs found

    Error analysis of Dobson spectrophotometer measurements of the total ozone content

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    A study of techniques for measuring atmospheric ozone is reported. This study represents the second phase of a program designed to improve techniques for the measurement of atmospheric ozone. This phase of the program studied the sensitivity of Dobson direct sun measurements and the ozone amounts inferred from those measurements to variation in the atmospheric temperature profile. The study used the plane - parallel Monte-Carlo model developed and tested under the initial phase of this program, and a series of standard model atmospheres

    Improving subject knowledge and subject pedagogic knowledge in employment based secondary initial teacher training in England

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    Each year in England about 6,000 trainee teachers qualify by undertaking an employment-based initial teacher training route (EBITT), where training is mainly school based. Government inspectors have found that trainees on this route are weaker in subject knowledge and subject pedagogic knowledge compared to trainees following the more traditional one year training course (PGCE) of which about a third of course time is University based. EBITT providers are currently seeking to improve the subject knowledge aspect of training. To support this work the TDA have published a model for developing trainees' subject knowledge for teaching and suggest that providers review their provision against the model. In addition EBITT providers must also meet a new requirement that the total training time should be a minimum of 60 days. This new requirement presents a challenge to EBITT providers as most of the subject knowledge enhancement will have to be school-based. This paper seeks to find out: - how trainee teachers acquire subject and subject pedagogic knowledge while based in a school and - whether teaching staff in schools have the required subject and subject pedagogic knowledge and skills for this enhanced role. Data have been collected from trainees, school-based mentors, school-based Initial Teacher Training Coordinators and University assessors over a one year period. Data about the way trainees acquire subject knowledge was interpreted against the TDA model. The study finds that: - trainees acquire subject and subject pedagogic knowledge in a variety of highly individualistic ways that suggests that the TDA model only partially explains what is happening in practice and - there is a significant training need to ensure schools are well equipped to deliver high quality subject focussed training.</p

    Implications of Lorentz covariance for the guidance equation in two-slit quantum interference

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    It is known that Lorentz covariance fixes uniquely the current and the associated guidance law in the trajectory interpretation of quantum mechanics for spin particles. In the non-relativistic domain this implies a guidance law for the electron which differs by an additional spin-dependent term from that originally proposed by de Broglie and Bohm. In this paper we explore some of the implications of the modified guidance law. We bring out a property of mutual dependence in the particle coordinates that arises in product states, and show that the quantum potential has scalar and vector components which implies the particle is subject to a Lorentz-like force. The conditions for the classical limit and the limit of negligible spin are given, and the empirical sufficiency of the model is demonstrated. We then present a series of calculations of the trajectories based on two-dimensional Gaussian wave packets which illustrate how the additional spin-dependent term plays a significant role in structuring both the individual trajectories and the ensemble. The single packet corresponds to quantum inertial motion. The distinct features encountered when the wavefunction is a product or a superposition are explored, and the trajectories that model the two-slit experiment are given. The latter paths exhibit several new characteristics compared with the original de Broglie-Bohm ones, such as crossing of the axis of symmetry.Comment: 27 pages including 6 pages of figure

    Comment on "Classical interventions in quantum systems II. Relativistic invariance"

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    In a recent paper [Phys. Rev. A 61, 022117 (2000)], quant-ph/9906034, A. Peres argued that quantum mechanics is consistent with special relativity by proposing that the operators that describe time evolution do not need to transform covariantly, although the measurable quantities need to transform covariantly. We discuss the weaknesses of this proposal.Comment: 4 pages, to appear in Phys. Rev.

    Secondary teachers' perceptions of the effectiveness of their pre-service education and strategies to improve pre-service education for teachers: A school based training route in England

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    This study aims to provide a deeper understanding of the impact of an EBITT course on teachers' early professional development, identify strengths of the course and also the ways in which the training could be improved. Data collected was recorded during individual face- to- face interviews using a structured interview schedule. In devising our approach we utilised the model suggested by Sharon Feiman-Nemser in her article How do Teachers Learn to Teach? in Cochran - Smith et. al. (2008) Handbook of Research on Teacher Education The data was analysed to explore (after 2-4 years reflection): ‱ which elements of initial training were valuable and less valuable ‱ what they have learned since the course ‱ which aspects of the course the teachers feel should be improved It was cross referenced against findings from national surveys of teachers in their post qualifying year of teaching (induction year) and early years of teaching conducted by the TDA. These findings were presented as part of a common wider international study on the same theme in four countries (UK, Spain, Australia, and Ireland)

    Large classical universes emerging from quantum cosmology

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    It is generally believed that one cannot obtain a large Universe from quantum cosmological models without an inflationary phase in the classical expanding era because the typical size of the Universe after leaving the quantum regime should be around the Planck length, and the standard decelerated classical expansion after that is not sufficient to enlarge the Universe in the time available. For instance, in many quantum minisuperspace bouncing models studied in the literature, solutions where the Universe leave the quantum regime in the expanding phase with appropriate size have negligible probability amplitude with respect to solutions leaving this regime around the Planck length. In this paper, I present a general class of moving gaussian solutions of the Wheeler-DeWitt equation where the velocity of the wave in minisuperspace along the scale factor axis, which is the new large parameter introduced in order to circumvent the abovementioned problem, induces a large acceleration around the quantum bounce, forcing the Universe to leave the quantum regime sufficiently big to increase afterwards to the present size, without needing any classical inflationary phase in between, and with reasonable relative probability amplitudes with respect to models leaving the quantum regime around the Planck scale. Furthermore, linear perturbations around this background model are free of any transplanckian problem.Comment: 8 pages, 1 figur

    Comments on the Quantum Potential Approach to a Class of Quantum Cosmological Models

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    In this comment we bring attention to the fact that when we apply the ontological interpretation of quantum mechanics, we must be sure to use it in the coordinate representation. This is particularly important when canonical tranformations that mix momenta and coordinates are present. This implies that some of the results obtained by A. B\l aut and J. Kowalski-Glikman are incorrect.Comment: 7 pages, LaTe

    Revisiting young masculinities through a sound art installation: What really counts?

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    What Really Counts? was a sound art installation created in 2019 through a collaboration between a sociologist and a multidisciplinary artist, working with in-depth interviews with young men recorded as part of a British feminist social research project in 1990, exploring sexualities and the threat of HIV/AIDS. In this article, we describe the evolution and staging of the sound art installation project, situating it within interdisciplinary literatures on the use of sociological archives and reanimation of analogue media in a digital age. Working within a fractured tradition of curated sociology, we consider the potential of interdisciplinary collaboration for refreshing sociological analytic practice, revealing the unrealised potential of archived data sets and utilising temporal displacement as a generative analytic strategy for feeling history. We are working with a 30-year time span characterised by a stretching of intergenerational experience in relation to expectations for and mediation of sex/gender. The project attempts to realise the potential for an experimental sociological practice through the staging of open-ended past–present encounters
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