491 research outputs found
A Review of the "Digital Turn" in the New Literacy Studies
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
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
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 of the decoherence. We also relate to an effective
decoherence parameter considered previously in literature. Finally we
discuss our model in the light of different measures of entanglement, i.e. the
von Neumann entropy , the entanglement of formation and the concurrence
, and we relate the decoherence parameter to the loss of
entanglement: .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
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
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 on square, triangular and honeycomb lattices
Recently-generated long strong-coupling series for the two-point Green's
functions of asymptotically free lattice 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 and in the energy . Square,
triangular, and honeycomb lattices are considered, as a test of universality
and in order to estimate systematic errors. Large- 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 , departing from their large- values only by a few per
mille even down to .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%)
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
In the context of the entangled state produced at the
resonance, we consider a modification of the usual
quantum-mechanical time evolution with a dissipative term, which contains only
one parameter denoted by and respects complete positivity. In this
way a decoherence effect is introduced in the time evolution of the 2-particle
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
. We also show how is related to the so-called ``decoherence
parameter'' , 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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