1,259,033 research outputs found
Unregulated Desires: Anomie, the “Rainbow Underclass” and Second-generation Alevi Kurdish Gangs in London
This article offers a case study of the adaptation strategies of a section of second-generation young male Alevi Kurds in London and the social conditions which make some of them more prone to join gangs and to reject mainstream institutions in their search for instant material rewards. It is instructive to use Durkheim’s analysis of society’s integrative and regulative functions and particularly his concept of anomie to understand a situation where the legitimate means in the pursuit of material wealth and comfort are out of balance with the demand, calling into question the legitimacy of the institutions which provide these functions. Those who cannot compete through existing institutions are more likely to seek alternative means to achieve these ends. Durkheim identified youth as more vulnerable to such unregulated desires and I argue that his approach offers valuable insights into the anomic pressures confronting second-generation migrant young men in particular
Microscopic theory of absorption and emission in nanostructured solar cells: Beyond the generalized Planck formula
Absorption and emission in inorganic bipolar solar cells based on low
dimensional structures exhibiting the effects of quantum confinement is
investigated in the framework of a comprehensive microscopic theory of the
optical and electronic degrees of freedom of the photovoltaic system. In a
quantum-statistical treatment based on non-equilibrium Green's functions, the
optical transition rates are related to the conservation of electronic
currents, providing a quantum version of the balance equations describing the
operation of a photovoltaic device. The generalized Planck law used for the
determination of emission from an excited semiconductor in quasi-equilibrium is
replaced by an expression of extended validity, where no assumptions on the
distribution of electrons and photons are made. The theory is illustrated by
the numerical simulation of single quantum well diodes at the radiative limit.Comment: 6 pages, 5 figures, extended LaTeX version of the EUPVSEC09
proceedings articl
On the influence of the cosmological constant on gravitational lensing in small systems
The cosmological constant Lambda affects gravitational lensing phenomena. The
contribution of Lambda to the observable angular positions of multiple images
and to their amplification and time delay is here computed through a study in
the weak deflection limit of the equations of motion in the Schwarzschild-de
Sitter metric. Due to Lambda the unresolved images are slightly demagnified,
the radius of the Einstein ring decreases and the time delay increases. The
effect is however negligible for near lenses. In the case of null cosmological
constant, we provide some updated results on lensing by a Schwarzschild black
hole.Comment: 8 pages, 1 figure; v2: extended discussion on the lens equation,
references added, results unchanged, in press on PR
Micromagnetic Simulation of Nanoscale Films with Perpendicular Anisotropy
A model is studied for the theoretical description of nanoscale magnetic
films with high perpendicular anisotropy. In the model the magnetic film is
described in terms of single domain magnetic grains with Ising-like behavior,
interacting via exchange as well as via dipolar forces. Additionally, the model
contains an energy barrier and a coupling to an external magnetic field.
Disorder is taken into account in order to describe realistic domain and domain
wall structures. The influence of a finite temperature as well as the dynamics
can be modeled by a Monte Carlo simulation.
Many of the experimental findings can be investigated and at least partly
understood by the model introduced above. For thin films the magnetisation
reversal is driven by domain wall motion. The results for the field and
temperature dependence of the domain wall velocity suggest that for thin films
hysteresis can be described as a depinning transition of the domain walls
rounded by thermal activation for finite temperatures.Comment: Revtex, Postscript Figures, to be published in J. Appl.Phy
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