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 $pp$ colliders with $\sqrt{s}=33$ 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, ‘agency’ has appeared in academic writings as a new way of referring to active involvement from below in development interventions. The concept of ‘agency’ 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 children’s 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 children’s 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 dernières années le terme ‘agency’ est apparu dans les écrits académiques comme une nouvelle manière de se référer à l’implication active de la base dans les interventions de développement. Le terme ‘agency’ part de l’hypothèse que les gens sont agents eux-mêmes, agissant et réagissant continûment aux circonstances. Dans l’activisme du travail des enfants, le concept a été appliqué aux enfants travailleurs dans le but de comprendre que, et dans le but d’améliorer leurs conditions de travail, les enfants doivent être organisés dans des organisations qui sont exclusivement et (idéalement) conduites par des enfants travailleurs. Ce papier tente d’évaluer dans quelle mesure les enfants travailleurs peuvent devenir agents du changement à travers leurs propres organisations. Le papier s’appuie sur deux études de cas menées par la fondation IREWOC. En 2002, une étude a été menée en Bolivie pour donner un sens concret au concept d’agencéité des enfants. Deuxièmement, en 2004/2005, une enquête a été réalisée sur le fonctionnement et l’impact des organisations d’enfants au Pérou, en Bolivie et au Brésil. La méthode de recherche appliquée est essentiellement anthropologique et utilise l’observation participante, les entrevues informelles (semi- informelles) et les entrevues de groupes avec des enfants travailleurs, leurs parents et des adultes représentant les organisations d’enfants travailleurs. Les deux enquêtes montrent qu’en se focalisant sur les enfants en tant que participants actifs, les contraintes structurelles dans lesquelles les enfants vivent doivent également être mises en évidence. On doit comprendre comment la pauvreté matérielle, la privation mentale et l’absence de capacité à se donner le pouvoir participent à modeler la résilience et la défiance, mais aussi la colère, la perte de confiance et la marginalisation

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'