77 research outputs found

    Study of Instanton Contributions to Moments of Nucleon Spin-Dependent Structure Functions

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    Instantons are the natural mechanism in non-perturbative QCD to remove helicity from valence quarks and transfer it to gluons and quark-antiquark pairs. To understand the extent to which instantons explain the so-called "spin crisis" in the nucleon, we calculate moments of spin-dependent structure functions in quenched QCD and compare them with the results obtained with cooled configurations from which essentially all gluon contributions except instantons have been removed. Preliminary results are presented.Comment: LATTICE98(matrixelement), 3 pages, 1 figur

    An ``Improved" Lattice Study of Semi-leptonic Decays of D-Mesons

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    We present results of a lattice computation of the matrix elements of the vector and axial-vector currents which are relevant for the semi-leptonic decays DKD \rightarrow K and DKD \rightarrow K^*. The computations are performed in the quenched approximation to lattice QCD on a 243×4824^3 \times 48 lattice at β=6.2\beta=6.2, using an O(a)O(a)-improved fermionic action. In the limit of zero lepton masses the semi-leptonic decays DKD \rightarrow K and DKD \rightarrow K^* are described by four form factors: fK+,V,A1f^{+}_K,V,A_1 and A2A_2, which are functions of q2q^2, where qμq^{\mu} is the four-momentum transferred in the process. Our results for these form factors at q2=0q^2=0 are: f^+_K(0)=0.67 \er{7}{8} , V(0)=1.01 \err{30}{13} , A_1(0)=0.70 \err{7}{10} , A_2(0)=0.66 \err{10}{15} , which are consistent with the most recent experimental world average values. We have also determined the q2q^2 dependence of the form factors, which we find to be reasonably well described by a simple pole-dominance model. Results for other form factors, including those relevant to the decays \dpi and \drho, are also given.Comment: 41 pages, uuencoded compressed postscript file containing 14 figures, LaTeX, Edinburgh Preprint 94/546 and Southampton Preprint SHEP 93/94-3

    Scholarship on Gender and Sport in Sex Roles and Beyond

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    In this paper we critically review how research on girls or women and sport has developed over the last 35 years. We use a post-positivist lens to explore the content of the papers published in Sex Roles in the area of women, gender and sport and examine the shifts in how gender and sport have been conceptualized in these accounts. In order to initiate a broader dialogue about the scholarly analysis of gender and sport, we subsequently explore ideas inspired by feminist theorizing that have dominated/guided related research in other outlets over this time period but have received relatively little attention in papers published in Sex Roles. We conclude by briefly making suggestions for further research in this area

    Isolation in Globalizing Academic Fields: A Collaborative Autoethnography of Early Career Researchers

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    This study examines academic isolation – an involuntary perceived separation from the academic field to which one aspires to belong, associated with a perceived lack of agency in terms of one’s engagement with the field – as a key challenge for researchers in increasingly globalized academic careers. While prior research describes early career researchers’ isolation in their institutions, we theorize early career researchers’ isolation in their academic fields and reveal how they attempt to mitigate isolation to improve their career prospects. Using a collaborative autoethnographic approach, we generate and analyze a dataset focused on the experiences of ten early career researchers in a globalizing business academic field known as Consumer Culture Theory. We identify bricolage practices, polycentric governance practices, and integration mechanisms that work to enhance early career researchers’ perceptions of agency and consequently mitigate their academic isolation. Our findings extend discussions on isolation and its role in new academic careers. Early career researchers, in particular, can benefit from a deeper understanding of practices that can enable them to mitigate isolation and reclaim agency as they engage with global academic fields

    Exploratory search in digital humanities: a study of visual keyword/result linking

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    While searching within digital humanities collections is an important aspect of digital humanities research, the search features provided are usually more suited to lookup search than exploratory search. This limits the ability of digital humanities scholars to undertake complex search tasks. Drawing upon recent studies on supporting exploratory search in academic digital libraries, we implemented two visual keyword/result linking approaches for searching within the Europeana collection; one that keeps the keywords linked to the search results and another that aggregates the keywords over the search result set. Using a controlled laboratory study, we assessed these approaches in comparison to the existing Europeana search mechanisms. We found that both visual keyword/result linking approaches were improvements over the baseline, with some differences between the new approaches that were dependent on the stage of the exploratory search process. This work illustrates the value of providing advanced search functionality within digital humanities collections to support exploratory search processes, and the need for further design and study of digital humanities search tools that support complex search task

    Selected readings from Military thought, 1963-1973 /

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    Item 422-IS/N 008-070-00471-2Translated from the journal Voyennaya mysl' [Military Thought]Includes bibliographical references.Mode of access: Internet

    Lattice study of the decay B0\overline{B}^{0} --> ϱ+\varrho^{+} lνl^{-}\overline{\nu}_{l} : model-independent determination of |Vub_{ub}|

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    We present results of a lattice computation of the vector and axial-vector current matrix elements relevant for the semileptonic decay B^0-bar -> rho^+ l^- nu_l-bar. The computations are performed in the quenched approximation of lattice QCD on a 24^3 x 48 lattice at beta = 6.2, using an O(a) improved fermionic action. Our principal result is for the differential decay rate, dGamma/dq^2, for the decay B^0-bar -> rho^+ l^- nu_l-bar in a region beyond the charm threshold, allowing a model-independent extraction of |V_{ub}| from experimental measurements. Heavy quark symmetry relations between radiative and semileptonic decays of B-bar mesons into light vector mesons are also discussed
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