8,626 research outputs found
Chaotic itinerancy and power-law residence time distribution in stochastic dynamical system
To study a chaotic itinerant motion among varieties of ordered states, we
propose a stochastic model based on the mechanism of chaotic itinerancy. The
model consists of a random walk on a half-line, and a Markov chain with a
transition probability matrix. To investigate the stability of attractor ruins
in the model, we analyze the residence time distribution of orbits at attractor
ruins. We show that the residence time distribution averaged by all attractor
ruins is given by the superposition of (truncated) power-law distributions, if
a basin of attraction for each attractor ruin has zero measure. To make sure of
this result, we carry out a computer simulation for models showing chaotic
itinerancy. We also discuss the fact that chaotic itinerancy does not occur in
coupled Milnor attractor systems if the transition probability among attractor
ruins can be represented as a Markov chain.Comment: 6 pages, 10 figure
q_T Uncertainties for W and Z Production
Analysis of semi-inclusive DIS hadroproduction suggests broadening of
transverse momentum distributions at small x below 1E-3 ~ 1E-2 which can be
modeled in the Collins-Soper-Sterman formalism by a modification of impact
parameter dependent parton densities. We investigate these consequences for the
production of electroweak bosons at the Tevatron and the LHC. If substantial
small-x broadening is observed in forward Z boson production in the Tevatron
Run-2, it will strongly affect the predicted q_T distributions for W and Z
boson production at the LHC.Comment: 4 pages, 2 figures; contribution to the XIII International Workshop
on Deep Inelastic Scattering (DIS 2005
Sensitivity of future collider facilities to WIMP pair production via effective operators and light mediators
We present extrapolations of the current mono-jet searches at the LHC to
potential future hadron collider facilities: LHC14, as well as colliders
with or 100 TeV. We consider both the effective operator approach
as well as one example of a light mediating particle
Bell's Theorem and Nonlinear Systems
For all Einstein-Podolsky-Rosen-type experiments on deterministic systems the
Bell inequality holds, unless non-local interactions exist between certain
parts of the setup. Here we show that in nonlinear systems the Bell inequality
can be violated by non-local effects that are arbitrarily weak. Then we show
that the quantum result of the existing Einstein-Podolsky-Rosen-type
experiments can be reproduced within deterministic models that include
arbitrarily weak non-local effects.Comment: Accepted for publication in Europhysics Letters. 14 pages, no
figures. In the Appendix (not included in the EPL version) the author says
what he really thinks about the subjec
Neutrino-Nucleus Cross Section Measurements using Stopped Pions and Low Energy Beta Beams
Two new facilities have recently been proposed to measure low energy
neutrino-nucleus cross sections, the nu-SNS (Spallation Neutron Source) and low
energy beta beams. The former produces neutrinos by pion decay at rest, while
the latter produces neutrinos from the beta decays of accelerated ions. One of
the uses of neutrino-nucleus cross section measurements is for supernova
studies, where typical neutrino energies are 10s of MeV. In this energy range
there are many different components to the nuclear response and this makes the
theoretical interpretation of the results of such an experiment complex.
Although even one measurement on a heavy nucleus such as lead is much
anticipated, more than one data set would be still better. We suggest that this
can be done by breaking the electron spectrum down into the parts produced in
coincidence with one or two neutrons, running a beta beam at more than one
energy, comparing the spectra produced with pions and a beta beam or any
combination of these.Comment: 6 pages, 6 figure
Working Children: their Agency and self-organization
In recent years, âagencyâ has appeared in academic writings as a new way of referring to active involvement from below in development interventions. The concept of âagencyâ starts from the assumption that people are actually agents themselves, continuously acting in and reacting to circumstances. In child labour activism, this concept has been applied to working children in the understanding that, in order to improve their working conditions, children should be organised in organizations that are exclusively for and (ideally) run by working children.
This paper aims to evaluate the extent to which child labourers can become agents of change through their own organizations. The paper will draw on two studies carried out by the IREWOC foundation. In 2002 a study was undertaken in Bolivia to give practical meaning to the concept of child agency. Secondly, in 2004/2005 an investigation was carried out on the functioning and impact of childrenâs organizations in Peru, Bolivia and Brazil. The applied research methods were mainly anthropological and used participant observation, (semi-) informal interviews and group interviewing with working children, their parents and adult representatives of the working childrenâs organizations.
Both investigations show that in focussing on children as active participants, the structural constraints under which children have to live also need to be highlighted. One needs to understand how material poverty, mental deprivation and disempowerment help to shape resilience and defiance, but also anger, distrust and marginalisation.Ces dernieÌres anneÌes le terme âagencyâ est apparu dans les eÌcrits acadeÌmiques comme une nouvelle manieÌre de se reÌfeÌrer aÌ lâimplication active de la base dans les interventions de deÌveloppement. Le terme âagencyâ part de lâhypotheÌse que les gens sont agents eux-meÌmes, agissant et reÌagissant continuÌment aux circonstances. Dans lâactivisme du travail des enfants, le concept a eÌteÌ appliqueÌ aux enfants travailleurs dans le but de comprendre que, et dans le but dâameÌliorer leurs conditions de travail, les enfants doivent eÌtre organiseÌs dans des organisations qui sont exclusivement et (ideÌalement) conduites par des enfants travailleurs.
Ce papier tente dâeÌvaluer dans quelle mesure les enfants travailleurs peuvent devenir agents du changement aÌ travers leurs propres organisations. Le papier sâappuie sur deux eÌtudes de cas meneÌes par la fondation IREWOC. En 2002, une eÌtude a eÌteÌ meneÌe en Bolivie pour donner un sens concret au concept dâagenceÌiteÌ des enfants. DeuxieÌmement, en 2004/2005, une enqueÌte a eÌteÌ reÌaliseÌe sur le fonctionnement et lâimpact des organisations dâenfants au PeÌrou, en Bolivie et au BreÌsil. La meÌthode de recherche appliqueÌe est essentiellement anthropologique et utilise lâobservation participante, les entrevues informelles (semi- informelles) et les entrevues de groupes avec des enfants travailleurs, leurs parents et des adultes repreÌsentant les organisations dâenfants travailleurs.
Les deux enqueÌtes montrent quâen se focalisant sur les enfants en tant que participants actifs, les contraintes structurelles dans lesquelles les enfants vivent doivent eÌgalement eÌtre mises en eÌvidence. On doit comprendre comment la pauvreteÌ mateÌrielle, la privation mentale et lâabsence de capaciteÌ aÌ se donner le pouvoir participent aÌ modeler la reÌsilience et la deÌfiance, mais aussi la coleÌre, la perte de confiance et la marginalisation
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Interaction of Public and Private Employment: Evidence from a German Government Move
We use the move of the seat of the German government from Bonn to Berlin in 1999 to test competing views about the impact of public employment on private sector activity in a local labor market. A relocated public sector job might create new jobs in an area as it increases demand for locally-produced goods and services, or crowd out existing jobs due to upward pressure on housing rents. Using employment data from a panel of a 50% sample of establishments across 190 Berlin postcodes, we apply a treatment intensity approach which takes the possibility of spillovers into account. Results indicate that the arrival of 100 public sector jobs into an area generates 55 additional jobs in the private sector. There is evidence of spillovers: relocations up to a distance of 1km from a postcode boundary increases employment in the private sector by 36 jobs. These effects are coming through job gains in the service sector, while manufacturing employment is not influenced by the relocation
Microstructure and Magnetic Properties of Very Thin CoCr Films Deposited on Different Underlayers by rf-Sputtering
Very thin CoCr films deposited on different underlayers on glass disk substrates were studied by the magneto-optic Kerr effect, VSM, torque magnetometry and TEM selected area diffraction. Square or near square perpendicular loops were obtained from Co/Ti, CoCr/Au, CoCr/Al, CoCr/C and CoCr/Si films. TEM SAD study revealed that the crystalline structure is a key factor determining the magnetic anisotropy of the very thin CoCr films. In particular, the c-axis of the hep CoCr films which exhibit square perpendicular loops is perpendicular to the film plane whilst that of the CoCr films which exhibit a thin and flat perpendicular loop lies in the film plane. The texture of the very thin CoCr films deposited on different underlayers is mainly dependent on the structure and texture of underlayers. The relation between the structure of CoCr and its underlayers is discussed
Observation of Ising-like critical fluctuations in frustrated Josephson junction arrays with modulated coupling energies
We report the results of ac sheet conductance measurements performed on fully
frustrated square arrays of Josephson junctions whose coupling energy is
periodically modulated in one of the principal lattice directions. Such systems
are predicted to exhibit two distinct transitions: a low-temperature Ising-like
transition triggered by the proliferation of domain walls and a
high-temperature transition driven by the vortex unbinding mechanism of the
Beresinskii-Kosterlitz-Thouless (BKT) theory. Both the superfluid and
dissipative components of the conductance are found to exhibit features which
unambiguously demonstrate the existence of a double transition whose properties
are consistent with the Ising-BKT scenario.Comment: To be published in Physica C (Proceedings of the 2nd European
Conference in School Format 'Vortex Matter in Superconductors'
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