72,342 research outputs found

    Quantizing the (0,4) Supersymmetric ADHM Sigma Model

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    We discuss the quantization of the ADHM sigma model. We show that the only quantum contributions to the effective theory come from the chiral anomalies and compute the first and second order terms. Finally the limit of vanishing instanton size is discussed.Comment: 19 pages phyzzx. Expanded discussion of various point and some minor correction

    A note on the UV behaviour of maximally supersymmetric Yang-Mills theories

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    The question of whether BPS invariants are protected in maximally supersymmetric Yang-Mills theories is investigated from the point of view of algebraic renormalisation theory. The protected invariants are those whose cohomology type differs from that of the action. It is confirmed that one-half BPS invariants (F4F^4) are indeed protected while the double-trace one-quarter BPS invariant (d2F4d^2F^4) is not protected at two loops in D=7, but is protected at three loops in D=6 in agreement with recent calculations. Non-BPS invariants, i.e. full superspace integrals, are also shown to be unprotected.Comment: 12 pages. Minor changes to text. References adde

    Strings and D-Branes with Boundaries

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    The covariant field equations of ten-dimensional super D-branes are obtained by considering fundamental strings whose ends lie in the superworldsurface of the D-brane. By considering in a similar fashion Dp-branes ending on D(p+2)-branes we derive equations describing D-branes with dual potentials, as well as the vector potentials.Comment: 12 pages, Late

    Twistor spaces for HKT manifolds

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    We construct the twistor space associated with an HKT manifold, that is, a hyper-K\"ahler manifold with torsion, a type of geometry that arises as the target space geometry in two-dimensional sigma models with (4,0) supersymmetry. We show that this twistor space has a natural complex structure and is a holomorphic fibre bundle over the complex projective line with fibre the associated HKT manifold. We also show how the metric and torsion of the HKT manifold can be determined from data on the twistor space by a reconstruction theorem. We give a geometric description of the sigma model (4,0) superfields as holomorphic maps (suitably understood) from a twistorial extension of (4,0) superspace (harmonic superspace) into the twistor space of the sigma model target manifold and write an action for the sigma model in terms of these (4,0) superfields.Comment: 15 pages, Phyzz

    On the Energy Momentum Tensor of the M-Theory Fivebrane

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    We construct the energy momentum tensor for the bosonic fields of the covariant formulation of the M-theory fivebrane within that formalism. We then obtain the energy for various solitonic solutions of the fivebrane equations of motion.Comment: 12 pages, LaTeX2e, uses vmargin.sty and amstex.st

    A Calibration Bound for the M-Theory Fivebrane

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    We construct a covariant bound on the energy-momentum of the M-fivebrane which is saturated by all supersymmetric configurations. This leads to a generalised notion of a calibrated geometry for M-fivebranes when the worldvolume gauge field is non-zero. The generalisation relevant for Dp-branes is also given.Comment: 9 pages, LaTeX2e, uses vmargin.sty. Typos corrected, a reference and a new discussion on conserved charges added. v4: A typo in the expression for the D-fourbrane energy correcte

    The challenges of cross-cultural research and teaching in family medicine: How can professional networks help?

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    Modern medical training emphasizes the value of understanding the patient’s ideas, concerns and expectations, and the use of their personal perspective to assist communication, diagnosis, and uptake of all appropriate health and treatment options. This requires doctors to be ‘culturally sensitive’, which “… involves an awareness and acceptance of cultural differences, self-awareness, knowledge of a patient’s culture, and adaptation of skills”. Yet most of us work in one country, and often one community, for much of our professional careers. Those who enter into academic pursuits will similarly be constrained by our own backgrounds and experiences, even though universities and medical schools often attract a multicultural membership. We therefore rely on our professional training and networks to extend our scope and understanding of how cultural issues impact upon our research and its relevance to our discipline and curricula. This article uses a reflexive narrative approach to examine the role and value of international networks through the lens of one individual and one organisation. It explores the extent to which such networks assist cross cultural sensitivity, using examples from its networks, and how these can (and have) impacted on greater cross-culturalism in our teaching and research outputs

    Teaching Language to Students with Autism

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    This meta-synthesis of the literature on methods of instruction to students with ASD examines the various methods of teaching language to students with ASD. While each student learns language at his or her own pace, the author has found that certain methods yield results quicker, and these methods need to be examined critically for any literature on their reliability, efficacy, and scientific research. If a student with autism can be taught language quickly, therefore mitigating any further delays in academic development relative to peers, then this methodology should be made accessible to all teachers of such students

    The strain energy analysis of swept boxes with ribs normal to the spars

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    The root constraint problem associated with uniform rectangular swept boxes, having ribs normal to the spars is considered. A strain energy method using self-equilibrating internal end load systems is used. Continues

    School workforce in England : November 2011

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