491 research outputs found

    A Review of the "Digital Turn" in the New Literacy Studies

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    Digital communication has transformed literacy practices and assumed great importance in the functioning of workplace, recreational, and community contexts. This article reviews a decade of empirical work of the New Literacy Studies, identifying the shift toward research of digital literacy applications. The article engages with the central theoretical, methodological, and pragmatic challenges in the tradition of New Literacy Studies, while highlighting the distinctive trends in the digital strand. It identifies common patterns across new literacy practices through cross-comparisons of ethnographic research in digital media environments. It examines ways in which this research is taking into account power and pedagogy in normative contexts of literacy learning using the new media. Recommendations are given to strengthen the links between New Literacy Studies research and literacy curriculum, assessment, and accountability in the 21st century

    Percolation properties of the 2D Heisenberg model

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    We analyze the percolation properties of certain clusters defined on configurations of the 2--dimensional Heisenberg model. We find that, given any direction \vec{n} in O(3) space, the spins almost perpendicular to \vec{n} form a percolating cluster. This result gives indications of how the model can avoid a previously conjectured Kosterlitz-Thouless phase transition at finite temperature T.Comment: 4 pages, 3 eps figures. Revised version (more clear abstract, some new references

    Decoherence of entangled kaons and its connection to entanglement measures

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    We study the time evolution of the entangled kaon system by considering the Liouville - von Neumann equation with an additional term which allows for decoherence. We choose as generators of decoherence the projectors to the 2-particle eigenstates of the Hamiltonian. Then we compare this model with the data of the CPLEAR experiment and find in this way an upper bound on the strength λ\lambda of the decoherence. We also relate λ\lambda to an effective decoherence parameter ζ\zeta considered previously in literature. Finally we discuss our model in the light of different measures of entanglement, i.e. the von Neumann entropy SS, the entanglement of formation EE and the concurrence CC, and we relate the decoherence parameter ζ\zeta to the loss of entanglement: 1−E1 - E.Comment: comments and references added, 18 pages, 1 figur

    "The non-ischemic repair" as a safe alternative method for repair of anterior post-infarction VSD

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    Patient's myocardium with post-infarction ventricular septum defect (VSD) is characterized by severe dysfunction. The "additive ischemia" caused by the operating process of cross-clamp ischemia and reperfusion injury, has a significant aggravation to the myocardium and overall negative impact to patient's outcome. We present a useful, safe and advantageous methodology in order to abolish "the toxic phase" of ischemia-reperfusion which is adopted by most as the "classic repair method" of myocardial protection. This abolition is in our opinion, particularly beneficial in order to reverse postoperatively the Low Cardiac Output Syndrome (LOS) and achieve better short and long term results. By using this method we avoid the aortic occlusion, the use of systematic hypothermia and any cardioplegic arrest. Furthermore, the total cardio-pulmonary bypass (CPB) time is significantly reduced, tissue debridement and stitching is much easier and safer. We think the method is applicable for every anterior and apical case of post-infarction septum rupture. After application of method in 3 patients with anterior post-myocardial infarction VSD, we are convinced that the patient will have a better postoperative haemodynamic condition and therefore a better outcome

    Bell inequalities for entangled kaons and their unitary time evolution

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    We investigate Bell inequalities for neutral kaon systems from Phi resonance decay to test local realism versus quantum mechanics. We emphasize the unitary time evolution of the states, that means we also include all decay product states, in contrast to other authors. Only this guarantees the use of the complete Hilbert space. We develop a general formalism for Bell inequalities including both arbitrary "quasi spin" states and different times; finally we analyze Wigner-type inequalities. They contain an additional term, a correction function h, as compared to the spin 1/2 or photon case, which changes considerably the possibility of quantum mechanics to violate the Bell inequality. Examples for special "quasi spin" states are given, especially those which are sensitive to the CP parameters epsilon and epsilon'.Comment: REVTeX, 22 page

    A strong-coupling analysis of two-dimensional O(N) sigma models with N≄3N\geq 3 on square, triangular and honeycomb lattices

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    Recently-generated long strong-coupling series for the two-point Green's functions of asymptotically free O(N){\rm O}(N) lattice σ\sigma models are analyzed, focusing on the evaluation of dimensionless renormalization-group invariant ratios of physical quantities and applying resummation techniques to series in the inverse temperature ÎČ\beta and in the energy EE. Square, triangular, and honeycomb lattices are considered, as a test of universality and in order to estimate systematic errors. Large-NN solutions are carefully studied in order to establish benchmarks for series coefficients and resummations. Scaling and universality are verified. All invariant ratios related to the large-distance properties of the two-point functions vary monotonically with NN, departing from their large-NN values only by a few per mille even down to N=3N=3.Comment: 53 pages (incl. 5 figures), tar/gzip/uuencode, REVTEX + psfi

    Energy loss of pions and electrons of 1 to 6 GeV/c in drift chambers operated with Xe,CO2(15%)

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    We present measurements of the energy loss of pions and electrons in drift chambers operated with a Xe,CO2(15%) mixture. The measurements are carried out for particle momenta from 1 to 6 GeV/c using prototype drift chambers for the ALICE TRD. Microscopic calculations are performed using input parameters calculated with GEANT3. These calculations reproduce well the measured average and most probable values for pions, but a higher Fermi plateau is required in order to reproduce our electron data. The widths of the measured distributions are smaller for data compared to the calculations. The electron/pion identification performance using the energy loss is also presented.Comment: 15 pages, 10 figures, accepted for publication in Nucl.Instrum.Meth.

    A model for decoherence of entangled beauty

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    In the context of the entangled B0Bˉ0B^0 \bar B^0 state produced at the ΄(4S)\Upsilon(4S) resonance, we consider a modification of the usual quantum-mechanical time evolution with a dissipative term, which contains only one parameter denoted by λ\lambda and respects complete positivity. In this way a decoherence effect is introduced in the time evolution of the 2-particle B0Bˉ0B^0 \bar B^0 state, which becomes stronger with increasing distance between the two particles. While our model of time evolution has decoherence for the 2-particle system, we assume that, after the decay of one of the two B mesons, the resulting 1-particle state obeys the purely quantum-mechanical time evolution. From the data on dilepton events we derive an upper bound on λ\lambda. We also show how λ\lambda is related to the so-called ``decoherence parameter'' ζ\zeta, which parameterizes decoherence in neutral flavoured meson--antimeson systems.Comment: 11 pages, revtex. Two references and some comments added, version to be published in Phys. Rev.
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