22,672 research outputs found

    Black and Minority Ethnic Trainees' Experiences of Physical Education Initial Teacher Training: Report to the Training and Development Agency

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    The first high-amplitude delta Scuti star in an eclipsing binary system

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    We report the discovery of the first high-amplitude delta Scuti star in an eclipsing binary, which we have designated UNSW-V-500. The system is an Algol-type semi-detached eclipsing binary of maximum brightness V = 12.52 mag. A best-fitting solution to the binary light curve and two radial velocity curves is derived using the Wilson-Devinney code. We identify a late A spectral type primary component of mass 1.49+/-0.02 M_sun and a late K spectral type secondary of mass 0.33+/-0.02 M_sun, with an inclination of 86.5+/-1.0 degrees, and a period of 5.3504751+/-0.0000006 d. A Fourier analysis of the residuals from this solution is performed using PERIOD04 to investigate the delta Scuti pulsations. We detect a single pulsation frequency of f_1 = 13.621+/-0.015 c/d, and it appears this is the first overtone radial mode frequency. This system provides the first opportunity to measure the dynamical mass for a star of this variable type; previously, masses have been derived from stellar evolution and pulsation models.Comment: 7 pages, 6 figures, 2 tables, for submission to MNRAS, v2: paper size change, small typographical changes to abstrac

    X-ray sources and their optical counterparts in the globular cluster M 22

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    Using XMM-Newton EPIC imaging data, we have detected 50 low-luminosity X-ray sources in the field of view of M 22, where 5 +/- 3 of these sources are likely to be related to the cluster. Using differential optical photometry, we have identified probable counterparts to those sources belonging to the cluster. Using X-ray spectroscopic and timing studies, supported by the optical colours, we propose that the most central X-ray sources in the cluster are cataclysmic variables, millisecond pulsars, active binaries and a blue straggler. We also identify a cluster of galaxies behind this globular cluster.Comment: 11 pages, 7 figures, accepted for publication in A&

    Microwave-Induced Dephasing in One-Dimensional Metal Wires

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    We report on the effect of monochromatic microwave (MW) radiation on the weak localization corrections to the conductivity of quasi-one-dimensional (1D) silver wires. Due to the improved electron cooling in the wires, the MW-induced dephasing was observed without a concomitant overheating of electrons over wide ranges of the MW power PMWP_{MW} and frequency ff. The observed dependences of the conductivity and MW-induced dephasing rate on PMWP_{MW} and ff are in agreement with the theory by Altshuler, Aronov, and Khmelnitsky \cite{Alt81}. Our results suggest that in the low-temperature experiments with 1D wires, saturation of the temperature dependence of the dephasing time can be caused by an MW electromagnetic noise with a sub-pW power.Comment: 4 pages with 4 figures, paper revised, accepted by Phys Rev Let

    Multiangle static and dynamic light scattering in the intermediate scattering angle range

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    We describe a light scattering apparatus based on a novel optical scheme covering the scattering angle range 0.5\dg \le \theta \le 25\dg, an intermediate regime at the frontier between wide angle and small angle setups that is difficult to access by existing instruments. Our apparatus uses standard, readily available optomechanical components. Thanks to the use of a charge-coupled device detector, both static and dynamic light scattering can be performed simultaneously at several scattering angles. We demonstrate the capabilities of our apparatus by measuring the scattering profile of a variety of samples and the Brownian dynamics of a dilute colloidal suspension

    High spatial resolution observations of CUDSS14A: a SCUBA-selected ultraluminous galaxy at high redshift

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    The definitive version is available at www.blackwell-synergy.com '. Copyright Blackwell Publishing DOI : 10.1046/j.1365-8711.2000.03822.xWe present a high-resolutionmillimetre interferometric image of the brightest SCUBA- selected galaxy from the Canada-UK deep SCUBA survey (CUDSS). We make a very clear detection at 1.3 mm, but fail to resolve any structure in the source.Peer reviewe

    The Subillimeter Properties of Extremely Red Objects in the CUDSS Fields

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    We discuss the submillimeter properties of Extremely Red Objects (EROs) in the two Canada-UK Deep Submillimeter Survey (CUDSS) Fields. We measure the mean submillimeter flux of the ERO population (to K < 20.7) and find 0.4 +/- 0.07 mJy for EROs selected by (I-K) > 4.0 and 0.56 +/- 0.09 mJy for EROs selected by (R-K) > 5.3 but, these measurements are dominated by discrete, bright submillimeter sources. We estimate that EROs produce 7-11% of the far-infrared background at 850um. This is substantially less than a previous measurement by Wehner, Barger & Kneib (2002) and we discuss possible reasons for this discrepancy. We show that ERO counterparts to bright submillimeter sources lie within the starburst region of the near-infrared color-color plot of Pozzetti & Mannucci (2000). Finally, we claim that pairs or small groups of EROs with separations of < 10 arcseconds often mark regions of strong submillimeter flux.Comment: 9 pages, 8 figures, accepted for publication in Ap

    Electron dephasing near zero temperature: an experimental review

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    The behavior of the electron dephasing time near zero temperature, τϕ0\tau_\phi^0, has recently attracted vigorous attention. This renewed interest is primarily concerned with whether τϕ0\tau_\phi^0 should reach a finite or an infinite value as T→T \to 0. While it is accepted that τϕ0\tau_\phi^0 should diverge if there exists only electron-electron (electron-phonon) scattering, several recent measurements have found that τϕ0\tau_\phi^0 depends only very weakly on temperature, if at all, when TT is sufficiently low. This article discusses the current experimental status of "the saturation problem", and concludes that the origin(s) for this widely observed saturation are still unresolved
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