53,344 research outputs found

    Over egging the pudding? Comments on Ojala and Thorpe

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    In a recent paper in ISCJ, Ojala and Thorpe offered a culturally based observation that questions the role and application of coaching in action sports. Their critique is focused on the action sport of snowboarding which, despite its’ comparatively recent inclusion in the Olympics, retains a different, almost collaborative rather than competitive culture more akin to other action sports such as skateboarding and surfing. Ojala and Thorpe then present Problem Based Learning (PBL) as the solution to many of these perceived ills, describing the positive characteristics of the approach and promoting its cultural fit with action sport environments and performers. In this paper we offer a different perspective, which questions the veracity of the data presented and the unquestioningly positive view of PBL as the answer. Our alternative, data-driven perspective suggests that action sport athletes are increasingly positive, or even desirous of good coaching, of which PBL is a possible approach; suitable for some athletes some of the time

    A Cultural Heritage Forum Celebrating Technological Innovation at Station X

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    We aim to encourage and support public participation in heritage through the development of Cultural Heritage Forums, a kind of cultural web portal that enables active participation of communities of interest in a way that complements rather than replaces visits to physical cultural institutions. The cultural heritage forum described here (Station X) is concerned with promoting an understanding of technology innovation in the areas of computing and cryptography. We propose a number of scenarios concerning how the forum can be designed, drawing on our earlier work in using knowledge modelling and text analysis to support the exploration of digital resources

    Electronic properties of deep levels in p‐type CdTe

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    DLTS and associated electrical measurements were made on unintentionally doped CdTe crystals obtained from several vendors, on Cu‐doped CdTe, and on Te‐annealed CdTe. All of the crystals were p‐type. Four majority carrier deep levels were observed in the temperature range from 100–300 K with activation energies relative to the valence band of 0.2, 0.41, 0.45, and 0.65 eV. Two of these levels were specific to certain crystals while the other two were seen in every sample and are attributed to common impurities or native defects. Fluctuations in the concentrations of levels across samples and as a result of modest sample heating (400 K) were also observed

    Specifying attracting cycles for Newton maps of polynomials

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    We show that for any set of n distinct points in the complex plane, there exists a polynomial p of degree at most n+1 so that the corresponding Newton map, or even the relaxed Newton map, for p has the given points as a super-attracting cycle. This improves the result due to Plaza and Romero (2011), which shows how to find such a polynomial of degree 2n. Moreover we show that in general one cannot improve upon degree n+1. Our methods allow us to give a simple, constructive proof of the known result that for each cycle length n at least 2 and degree d at least 3, there exists a polynomial of degree d whose Newton map has a super-attracting cycle of length n.Comment: 18 pages, 2 figure

    Universality of soft and collinear factors in hard-scattering factorization

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    Universality in QCD factorization of parton densities, fragmentation functions, and soft factors is endangered by the process dependence of the directions of Wilson lines in their definitions. We find a choice of directions that is consistent with factorization and that gives universality between e^+e^- annihilation, semi-inclusive deep-inelastic scattering, and the Drell-Yan process. Universality is only modified by a time-reversal transformation of the soft function and parton densities between Drell-Yan and the other processes, whose only effect is the known reversal of sign for T-odd parton densities like the Sivers function. The modifications of the definitions needed to remove rapidity divergences with light-like Wilson lines do not affect the results.Comment: 4 pages. Extra references. Text and references as in published versio

    Proof of Factorization of Fragmentation Function in Non-Equilibrium QCD

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    In this paper we prove factorization of fragmentation function in non-equilibrium QCD by using Schwinger-Keldysh closed-time path integral formalism. We use the background field method of QCD in a pure gauge in path integral approach to prove factorization of fragmentation function in non-equilibrium QCD. Our proof is valid in any arbitrary gauge fixing parameter α\alpha. This may be relevant to study hadron production from quark-gluon plasma at high energy heavy-ion colliders at RHIC and LHC.Comment: 13 pages latex, (Final Published Version, Annals of Physics

    Spruce Budworm and Other Lepidopterous Prey of Eumenid Wasps (Hymenoptera: Eumenidae) in Spruce-Fir Forests of Maine

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    Three species of eumenid wasps, Ancistrocerus adiabatus, Ancistrocerus antilope, and Euodynerus Ieucomelas, accepted and provisioned trap-nesting blocks with lepidopterous larvae, A pyralid. Nephopteryx sp., was the most commonly provisioned prey. A. adiabarus and E. leucomelas preyed on late instars of the spruce budworm, Choristoneura fumiferana: however. budworms accounted for only 6% of the provisioned prey. Estimates of budworm population densities before and after wasp predation, and subsample-s of provisioned prey indicated no significant reductions i = 0.065%) in budworm populations attributable to trap-nesting wasps

    Prospects for the future of narrow bandgap materials

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    Recently there has been greatly expended interest in narrow bandgap materials. Modern epitaxial techniques and the growing interest in nanostructures have provided areas of application for some of the unique properties of the narrow bandgap material. As always, one of the primary sources of interest is the small bandgap which makes them the material of choice for many applications in the infrared. However, in recent years their other unique properties have been the basis for a broader set of interests in narrow bandgap semiconductors. The type II band offsets (InAs/GaSb) have been the basis for novel tunnel devices and infrared superlattices. The very small effective masses inherent in small bandgap materials make them the obvious candidates in which to observe quantum confinement effects at larger dimensions than in materials of larger effective mass and wider gap. The ease of making electrical contact to some of the materials (ohmic contact to n-InAs) has made them the material of choice for electrical nanostructures. The ability to put in large amounts of magnetic ions to make magnetic semiconductors has led to a number of novel properties. The technical importance of a narrow bandgap and the unique applications promised by some of the other properties of these materials bode well for substantial research in narrow bandgap semiconductors well into the next decade
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