6,641 research outputs found

    A New Field of Dreams: A Study of the Writing Major

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    Within Writing Studies, the tension between pedagogy and theory, between teaching and disciplinary status receives much commentary. This dissertation explores that tension within the context of the undergraduate Writing major. I begin by reviewing scholarship about advanced composition, advanced Writing, and the Writing major. I read this literature in light of concerns about student subjectivity, authorship, and disciplinary participation. Through that reading, I explore the conflicted status of the student subject imagined within this literature. The subject I discern contains elements of what Susan Miller describes as the normative subject of composition as well as elements of a revised and politically astute Writing Studies. In chapter two, I demonstrate how these elements also appeared in the discourse of students who participated in the two-institution study of undergraduate Writing majors upon which the remaining chapters of this dissertation are based. In chapter three, I argue that when students articulated the work of the Writing major, they privileged relational, affective labor in ways that may potentially affirm arguments for the Writing major as a vehicle for disciplinarity as well as assert pedagogy\u27s continued importance within Writing Studies even as its practitioners pursue academic professionalization. Chapter four examines students\u27 discourse and their writing for scholarly, professional, and civic purposes in order to demonstrate how students contribute to-- and participate in--goals widely held within Writing Studies through academic, creative, and creative nonfiction forms. In the fifth and concluding chapter, I consider the implications of this research for scholarly writing practice and for writing pedagogy. I also acknowledge the limitations of this current project and outline an agenda for future research. Ultimately, this dissertation encourages a broad understanding of students\u27 disciplinary contribution and participation

    “Weaving all of them together”: How Writing Majors Talk about Creative Writing

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    The labels “creative” and “creative writing” serve several purposes in the discourses of undergraduate writing majors. In a study of students in two writing major programs, students often exerted significant effort to negotiate among diverse writing experiences and to integrate different understandings of writing. Their efforts mirror scholars’ conversations about negotiation and integration at the level of curricula and programs. Writing majors in this study raised issues relevant to the well-established curricular domains of theoretical knowledge, professional expertise, and civic action. They explained their insights using a mix of idiosyncratic, institutional, and disciplinary language that frequently relied on forms of “’not’ talk” (Reiff and Bawarshi). One term around which much of their blended-language and ‘not’ talk centered was “creative.” Students used the label “creative” to mean writing fiction and poetry, personal expression, creative nonfiction prose, nonacademic discourse, and flexibility in style and genre. Frequently, these uses were mixed together or slipped casually from one to another. These findings suggest that as students engage with disciplinary purposes for writing in the major, they draw from a range of literacy discourses to negotiate among and to integrate diverse forms of knowledge

    Deep Convolutional Neural Networks as strong gravitational lens detectors

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    Future large-scale surveys with high resolution imaging will provide us with a few 10510^5 new strong galaxy-scale lenses. These strong lensing systems however will be contained in large data amounts which are beyond the capacity of human experts to visually classify in a unbiased way. We present a new strong gravitational lens finder based on convolutional neural networks (CNNs). The method was applied to the Strong Lensing challenge organised by the Bologna Lens Factory. It achieved first and third place respectively on the space-based data-set and the ground-based data-set. The goal was to find a fully automated lens finder for ground-based and space-based surveys which minimizes human inspect. We compare the results of our CNN architecture and three new variations ("invariant" "views" and "residual") on the simulated data of the challenge. Each method has been trained separately 5 times on 17 000 simulated images, cross-validated using 3 000 images and then applied to a 100 000 image test set. We used two different metrics for evaluation, the area under the receiver operating characteristic curve (AUC) score and the recall with no false positive (Recall0FP\mathrm{Recall}_{\mathrm{0FP}}). For ground based data our best method achieved an AUC score of 0.9770.977 and a Recall0FP\mathrm{Recall}_{\mathrm{0FP}} of 0.500.50. For space-based data our best method achieved an AUC score of 0.9400.940 and a Recall0FP\mathrm{Recall}_{\mathrm{0FP}} of 0.320.32. On space-based data adding dihedral invariance to the CNN architecture diminished the overall score but achieved a higher no contamination recall. We found that using committees of 5 CNNs produce the best recall at zero contamination and consistenly score better AUC than a single CNN. We found that for every variation of our CNN lensfinder, we achieve AUC scores close to 11 within 6%6\%.Comment: 9 pages, accepted to A&

    Parton cascade description of relativistic heavy-ion collisions at CERN SPS energies ?

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    We examine Pb+Pb collisions at CERN SPS energy 158 A GeV, by employing the earlier developed and recently refined parton-cascade/cluster-hadronization model and its Monte Carlo implementation. This space-time model involves the dynamical interplay of perturbative QCD parton production and evolution, with non-perturbative parton-cluster formation and hadron production through cluster decays. Using computer simulations, we are able to follow the entwined time-evolution of parton and hadron degrees of freedom in both position and momentum space, from the instant of nuclear overlap to the final yield of particles. We present and discuss results for the multiplicity distributions, which agree well with the measured data from the CERN SPS, including those for K mesons. The transverse momentum distributions of the produced hadrons are also found to be in good agreement with the preliminary data measured by the NA49 and the WA98 collaboration for the collision of lead nuclei at the CERN SPS. The analysis of the time evolution of transverse energy deposited in the collision zone and the energy density suggests an existence of partonic matter for a time of more than 5 fm.Comment: 16 pages including 7 postscript figure

    Heavy resonance production in high energy nuclear collisions

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    We estimate freezeout conditions for ss, cc, and bb quarks in high energy nuclear collisions. Freezeout is due either to loss of thermal contact, or to particles ``wandering'' out of the region of hot matter. We then develop a thermal recombination model in which both single-particle (quark and antiquark) and two-particle (quark-antiquark) densities are conserved. Conservation of two-particle densities is necessary because quarks and antiquarks are always produced in coincidence, so that the local two-particle density can be much larger than the product of the single-particle densities. We use the freezeout conditions and recombination model to discuss heavy resonance production at zero baryon density in high energy nuclear collisions.Comment: revtex, 15 pages, no figures, KSUCNR-009-9

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    Thermal quark production in ultra-relativistic nuclear collisions

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    We calculate thermal production of u, d, s, c and b quarks in ultra-relativistic heavy ion collisions. The following processes are taken into account: thermal gluon decay (g to ibar i), gluon fusion (g g to ibar i), and quark-antiquark annihilation (jbar j to ibar i), where i and j represent quark species. We use the thermal quark masses, mi2(T)≃mi2+(2g2/9)T2m_i^2(T)\simeq m_i^2 + (2g^2/9)T^2, in all the rates. At small mass (mi(T)<2Tm_i(T)<2T), the production is largely dominated by the thermal gluon decay channel. We obtain numerical and analytic solutions of one-dimensional hydrodynamic expansion of an initially pure glue plasma. Our results show that even in a quite optimistic scenario, all quarks are far from chemical equilibrium throughout the expansion. Thermal production of light quarks (u, d and s) is nearly independent of species. Heavy quark (c and b) production is quite independent of the transition temperature and could serve as a very good probe of the initial temperature. Thermal quark production measurements could also be used to determine the gluon damping rate, or equivalently the magnetic mass.Comment: 14 pages (latex) plus 6 figures (uuencoded postscript files); CERN-TH.7038/9

    Naive mean field approximation for image restoration

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    We attempt image restoration in the framework of the Baysian inference. Recently, it has been shown that under a certain criterion the MAP (Maximum A Posterior) estimate, which corresponds to the minimization of energy, can be outperformed by the MPM (Maximizer of the Posterior Marginals) estimate, which is equivalent to a finite-temperature decoding method. Since a lot of computational time is needed for the MPM estimate to calculate the thermal averages, the mean field method, which is a deterministic algorithm, is often utilized to avoid this difficulty. We present a statistical-mechanical analysis of naive mean field approximation in the framework of image restoration. We compare our theoretical results with those of computer simulation, and investigate the potential of naive mean field approximation.Comment: 9 pages, 11 figure

    Effect of baryon density on parton production, chemical equilibration and thermal photon emission from quark gluon plasma

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    The effect of baryon density on parton production processes of gg⇌ggggg\rightleftharpoons ggg and gg⇌qqˉgg\rightleftharpoons q{\bar q} is studied using full phase space distribution function and also with inclusion of quantum statistics i.e. Pauli blocking and Bose enhancement factors, in the case of both saturated and unsaturated quark gluon plasma. The rate for the process gg⇌qqˉgg \rightleftharpoons q{\bar q} is found to be much less as compared to the most commonly used factorized result obtained on the basis of classical approximation. This discrepancy, which is found both at zero as well as at finite baryon densities, however, is not due to the lack of quantum statistics in the classical approximation, rather due to the use of Fermi-Dirac and Bose-Einstein distribution functions for partons instead of Boltzmann distribution which is appropriate under such approximation. Interestingly, the rates of parton production are found to be insensitive to the baryo-chemical potential particularly when the plasma is unsaturated although the process of chemical equilibration strongly depends on it. The thermal photon yields, have been calculated specifically from unsaturated plasma at finite baryon density. The exact results obtained numerically are found to be in close agreement with the analytic expression derived using factorized distribution functions appropriate for unsaturated plasma. Further, it is shown that in the case of unsaturated plasma, the thermal photon production is enhanced with increasing baryon density both at fixed temperature and fixed energy density of the quark gluon plasma.Comment: Latex, 24 pages, 6 postscript figures. Submitted to Phys. Rev.
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