15,189 research outputs found
Irreversibility line and low-field grain-boundary pinning in electron-doped superconducting thin films
AC magnetic susceptibilities of electron-doped Pr_{1.85}Ce_{0.15}CuO_4 (PCCO)
and Sm_{1.85}Ce_{0.15}CuO_4 (SCCO) granular thin films have been measured as a
function of temperature and magnetic-field strength. Depending on the level of
homogeneity of our films, two different types of the irreversibility line (IL)
defined as the intergrain-loss peak temperature in the imaginary part of
susceptibility have been found. The obtained results are described via the
critical-state model taking into account the low-field grain-boundary pinning.
The extracted pinning-force densities in more granular SCCO films turn out to
be four times larger than their counterparts in less granular PCCO films
Counterions at charge-modulated substrates
We consider counterions in the presence of a single planar surface with a
spatially inhomogeneous charge distribution using Monte-Carlo simulations and
strong-coupling theory. For high surface charges, multivalent counterions, or
pronounced substrate charge modulation the counterions are laterally correlated
with the surface charges and their density profile deviates strongly from the
limit of a smeared-out substrate charge distribution, in particular exhibiting
a much increased laterally averaged density at the surface.Comment: 7 page
Adubação nitrogenada no sistema plantio direto do arroz, após pastagem.
Este trabalho foi desenvolvido com o objetivo de adotar um manejo mais adequado da adubação nitrogenada no sistema plantio direto do arroz de terras altas, cultivado após pastagem.bitstream/item/59055/1/Foco-45.pd
Social Representation of Elderly Violence
One of the consequences of aging is the stress of necessary adjustments in living arrangements which carry with it changes in social participation and dependency. These give rise to the phenomenon under investigation in this study: that of violence…often blatant, but sometimes muted. The literature speaks of an increase in the phenomenon worldwide which can be obscured in the non evident cases. This study attempts to surmount the obstacles not only by delving into the epidemiology, but investigating its significance and representations via the comparison of expressions from a studied population in two countries: United States and Portugal. We present the partial results of a research using both qualitative and quantitative methodology that examines the social representations of elderly violence using the framework of Moscovici's Social Representation Theory. We analysed the thoughts of sixty participants divided into three categories : elderly individuals, family members and health workers. Content analysis was treated by the ALCESTE software that allows the comparison between the elements of the corpus of words or sentences. The results revealed the social representation of elderly violence for the subjects considering their cultural differences. It also highlights the importance of the reciprocity between individuals and the environment where violence occurs. In addition, evidences the lack of educational preparation of two main support pillars to the elderly: family and health professionals. The similarities of terms associated with violence points to the possibility of using a consensual concept proposed by the authors to promote preventative strategies while discussing the phenomenon
Irrigated rice area estimation using remote sensing techniques: Project's proposal and preliminary results
The development of a methodology for annual estimates of irrigated rice crop in the State of Rio Grande do Sul, Brazil, using remote sensing techniques is proposed. The project involves interpretation, digital analysis, and sampling techniques of LANDSAT imagery. Results are discussed from a preliminary phase for identifying and evaluating irrigated rice crop areas in four counties of the State, for the crop year 1982/1983. This first phase involved just visual interpretation techniques of MSS/LANDSAT images
Fracturing highly disordered materials
We investigate the role of disorder on the fracturing process of
heterogeneous materials by means of a two-dimensional fuse network model. Our
results in the extreme disorder limit reveal that the backbone of the fracture
at collapse, namely the subset of the largest fracture that effectively halts
the global current, has a fractal dimension of . This exponent
value is compatible with the universality class of several other physical
models, including optimal paths under strong disorder, disordered polymers,
watersheds and optimal path cracks on uncorrelated substrates, hulls of
explosive percolation clusters, and strands of invasion percolation fronts.
Moreover, we find that the fractal dimension of the largest fracture under
extreme disorder, , is outside the statistical error bar of
standard percolation. This discrepancy is due to the appearance of trapped
regions or cavities of all sizes that remain intact till the entire collapse of
the fuse network, but are always accessible in the case of standard
percolation. Finally, we quantify the role of disorder on the structure of the
largest cluster, as well as on the backbone of the fracture, in terms of a
distinctive transition from weak to strong disorder characterized by a new
crossover exponent.Comment: 5 pages, 4 figure
Dynamical reentrance and geometry imposed quantization effects in Nb-AlOx-Nb Josephson junction arrays
In this paper, we report on different phenomena related to the magnetic
properties of artificially prepared highly ordered (periodic) two-dimensional
Josephson junction arrays (2D-JJA) of both shunted and unshunted Nb-AlOx-Nb
tunnel junctions. By employing mutual-inductance measurements and using a
high-sensitive bridge, we have thoroughly investigated (both experimentally and
theoretically) the temperature and magnetic field dependence of complex AC
susceptibility of 2D-JJA. We also demonstrate the use of the scanning SQUID
microscope for imaging the local flux distribution within our unshunted arrays
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