1,882 research outputs found
The Vision of Future Primary School Teachers as to Education for Sustainable Development from a Competency-Based Approach
his study was established as an interpretive or phenomenological approach, based on a content analysis of the vision of future primary education teachers for education for sustainable development and its relationship with professional sustainability competencies. The sample consisted of 367 people—113 men, 247 women, and 7 who preferred not to say—with an average age of 21.82 ± 2.56, all of whom were studying for a Primary Education teaching degree at the Universities of Zaragoza and Granada in Spain. The content analysis process followed the phases proposed by Bardin: pre-analysis, based on an adaptation of the Cebrián and Junyent questionnaire; exploitation of the material, wherein the fragments to be coded were selected and coded one by one, by consensus between the three researchers; data processing and interpretation, using the QRS NVIVO 11 software. The main results show that respect, coexistence, and collaboration are the normative principles that regulate behavior and that the competencies related to education for sustainability have to do with managing emotions, critical thinking, clarifying values, and contextualizing problems. Furthermore, there is a lack of pragmatism that shows the need to develop the field of education for sustainable development through experiential, interdisciplinary, collaborative, and critical educational plans and projects
Correlations due to localization in quantum eigenfunctions of disordered microwave cavities
Non-universal correlations due to localization are observed in statistical
properties of experimental eigenfunctions of quantum chaotic and disordered
microwave cavities. Varying energy {E} and mean free path {l} enable us to
experimentally tune from localized to delocalized states. Large level-to-level
Inverse Participation Ratio (IPR I_{2}) fluctuations are observed for the
disordered billiards, whose distribution is strongly asymmetric about .
The density auto-correlations of eigenfunctions are shown to decay
exponentially and the decay lengths are experimentally determined. All the
results are quantitatively consistent with calculations based upon nonlinear
sigma-models.Comment: 4 pages, LaTex, 5 .jpg figures. This paper with 5 embedded postscript
figures available (PS,PDF) at http://sagar.physics.neu.edu/preprints
Intensity Fluctuations in Closed and Open Systems
We consider the intensity pattern, generated by a monochromatic source, in a
disordered cavity coupled to the environment. For weak coupling, and when the
source frequency is tuned to a resonance, the intensity distribution is close
to Porter-Thomas distribution. When the coupling increases, gradually crosses
over to the Rayleigh distribution. The joint probability distribution for
intensities at two different points is also discussed.Comment: 11 pages, LATEX, no figure
"Level Curvature" Distribution for Diffusive Aharonov-Bohm Systems: analytical results
We calculate analytically the distributions of "level curvatures" (LC) (the
second derivatives of eigenvalues with respect to a magnetic flux) for a
particle moving in a white-noise random potential.
We find that the Zakrzewski-Delande conjecture is still valid even if the
lowest weak localization corrections are taken into account. The ratio of mean
level curvature modulus to mean dissipative conductance is proved to be
universal and equal to in agreement with available numerical data.Comment: 12 pages. Submitted to Phys.Rev.
Fluctuating "order parameter" for a quantum chaotic system with partially broken time-reversal symmetry
The functional defined as the squared modulus of the spatial average of the
wave function squared, plays the role of an ``order parameter'' for the
transition between Hamiltonian ensembles with orthogonal and unitary symmetry.
Upon breaking time-reversal symmetry, the order parameter crosses over from one
to zero. We compute its distribution in the crossover regime and find that it
has large fluctuations around the ensemble average. These fluctuations imply
long-range spatial correlations in the eigenfunction and non-Gaussian
perturbations of eigenvalues, in precise agreement with results by Fal'ko and
Efetov and by Taniguchi, Hashimoto, Simons, and Altshuler. As a third
implication of the order-parameter fluctuations we find correlations in the
response of an eigenvalue to independent perturbations of the system.Comment: 4 pages, REVTeX-3.0, 1 figure. Reference added to Y. V. Fyodorov and
A. D. Mirlin, Phys. Rev. B 51, 13403 (1995
Influence of a low magnetic field on the thermal diffusivity of Bi-2212
The thermal diffusivity of a Bi-2212 polycrystalline sample has been measured
under a 1T magnetic field applied perpendicularly to the heat flux. The
magnetic contribution to the heat carrier mean free path has been extracted and
is found to behave as a simple power law. This behavior can be attributed to a
percolation process of electrons in the vortex lattice created by the magnetic
field.Comment: 10 pages, 3 figures; to be published in Phys. Rev.
A Universal Interacting Crossover Regime in Two-Dimensional Quantum Dots
Interacting electrons in quantum dots with large Thouless number in the
three classical random matrix symmetry classes are well-understood. When a
specific type of spin-orbit coupling known to be dominant in two dimensional
semiconductor quantum dots is introduced, we show that a new interacting
quantum critical crossover energy scale emerges and low-energy quasiparticles
generically have a decay width proportional to their energy. The low-energy
physics of this system is an example of a universal interacting crossover
regime.Comment: 4 pages, 1 figur
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