Two-step phase changes in cubic relaxor ferroelectrics

The field-driven conversion between the zero-field-cooled frozen relaxor state and a ferroelectric state of several cubic relaxors is found to occur in at least two distinct steps, after a period of creep, as a function of time. The relaxation of this state back to a relaxor state under warming in zero field also occurs via two or more sharp steps, in contrast to a one-step relaxation of the ferroelectric state formed by field-cooling. An intermediate state can be trapped by interrupting the polarization. Giant pyroelectric noise appears in some of the non-equilibrium regimes. It is suggested that two coupled types of order, one ferroelectric and the other glassy, may be required to account for these data.Comment: 27 pages with 8 figures to appear in Phys. Rev.

A new species of Hyalella (Crustacea, Amphipoda, Dogielinotidae) from the Atlantic Forest of Misiones, Argentina

The freshwater genus Hyalella Smith, 1874 has a distribution restricted to the Western Hemisphere with most species being found in South America. In this report we describe a new species of Hyalella from the Atlantic Forest of the Misiones province, Argentina.Fil: Colla, Maria Florencia. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División de Zoología Invertebrados; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: César, Inés Irma. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División de Zoología Invertebrados; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Performance evaluation in competitive REE models

Our basic premise is that fund managers performance is related to superior information about an asset payoff. We investigate the relationship between managerial skills and trading behavior within a two-period rational expectation equilibrium (REE) model where agents trade on private information in the first round, while a public signal arrives at the second date that makes traders revise their beliefs and retrade. The public signal can be related to the asset payoff, or to variables not related to fundamentals (noise), or both. We characterize the unique partially revealing REE and explore the drivers of price dynamics and trading behavior. Our main prediction is that good managers are contrarian traders, while bad managers are momentum traders when public news arrive to the market. Furthermore, the change in holdings of each type of trader is monotonic on the traders' skills. Based on these predictions, we propose new performance evaluation measures that rely on the manager's change in holdings around the arrival of public news rather than his past performance. A byproduct of our analysis is the proposal of a new protocol for performance evaluation and Due Diligence (DD) procedures.REE; performance evaluation; mutual fund; hedge funds; talent; informed traders; due diligence

Quantum noise detection: a portable and educational system

Quantum noise is a key feature of laser beams. It is both a limiting effect in contemporary optical measurements and a manifestation of the quantum nature of light. Its properties distinguish it from classical noise. We demonstrate a simple, reliable, and portable apparatus using low cost commercial lasers and electronics that provides evidence of these properties.This work was supported by Centre of Excellence for Quantum-Atom Optics of the Australian Research Council

Synchrotron x-ray Studies of Superlattice Ordering in Pb(Mg1/3Nb2/3)O3 Single Crystals Doped with PbTiO3

The temperature dependence of the superlattice reflections: a) F spots and b) alpha spots in a lead magnesium niobate (PMN) single crystals containing 0% and 6% of PbTiO3 (PT) has been studied using synchrotron x-ray scattering techniques. (No superlattice reflections were found in PMN doped with 32% PT). Analysis of the temperature dependence of the alpha spots suggests the existence of the correlated anti-parallel atomic displacements that form nanoregions different from the chemical nanodomains. While the correlation length is temperature independent, the magnitude of these displacements increases on cooling below the freezing temperature Tf. Intensities of the alpha spots above this temperature become indistinguishable from the background. Our results show that value of Tf for each composition is very close to the one obtained from a Vogel-Fulcher fit to the frequency dependence of the dielectric constant maximum Tm. The relation of these correlated anti-ferrodistortive fluctuations to polar ferroelectric nanodomains and relaxor behavior needs further study.Comment: 10 pages, 7 figures, Conference-Fundamental Physics of Ferroelectrics 200

Cluster-induced crater formation

Using molecular-dynamics simulation, we study the crater volumes induced by energetic impacts ($v= 1- 250$ km/s) of projectiles containing up to N=1000 atoms. We find that for Lennard-Jones bonded material the crater volume depends solely on the total impact energy $E$. Above a threshold \Eth, the volume rises linearly with $E$. Similar results are obtained for metallic materials. By scaling the impact energy $E$ to the target cohesive energy $U$, the crater volumes become independent of the target material. To a first approximation, the crater volume increases in proportion with the available scaled energy, $V=aE/U$. The proportionality factor $a$ is termed the cratering efficiency and assumes values of around 0.5.Comment: 9 page

Coherent search of continuous gravitational wave signals: extension of the 5-vectors method to a network of detectors

We describe the extension to multiple datasets of a coherent method for the search of continuous gravitational wave signals, based on the computation of 5-vectors. In particular, we show how to coherently combine different datasets belonging to the same detector or to different detectors. In the latter case the coherent combination is the way to have the maximum increase in signal-to-noise ratio. If the datasets belong to the same detector the advantage comes mainly from the properties of a quantity called {\it coherence} which is helpful (in both cases, in fact) in rejecting false candidates. The method has been tested searching for simulated signals injected in Gaussian noise and the results of the simulations are discussed.Comment: 9 pages, 2 figures. Journal of Physics: Conference Series, in pres

Lattice Model of an Ionic Liquid at an Electrified Interface

We study ionic liquids interacting with electrified interfaces. The ionic fluid is modeled as a Coulomb lattice gas. We compare the ionic density profiles calculated using a popular modified Poisson-Boltzmann equation with the explicit Monte Carlo simulations. The modified Poisson-Boltzmann theory fails to capture the structural features of the double layer and is also unable to correctly predict the ionic density at the electrified interface. The lattice Monte Carlo simulations qualitatively capture the coarse-grained structure of the double layer in the continuum. We propose a convolution relation that semiquantitatively relates the ionic density profiles of a continuum ionic liquid and its lattice counterpart near an electrified interface

Method for all-sky searches of continuous gravitational wave signals using the frequency-Hough transform

In this paper we present a hierarchical data analysis pipeline for all-sky searches of continuous gravitational wave signals, like those emitted by spinning neutron stars asymmetric with respect to the rotation axis, with unknown position, rotational frequency and spin-down. The core of the pipeline is an incoherent step based on a particularly efficient implementation of the Hough transform, that we call frequency-Hough, that maps the data time-frequency plane to the source frequency/spin-down plane for each fixed direction in the sky. Theoretical ROCs and sensitivity curves are computed and the dependency on various thresholds is discussed. A comparison of the sensitivity loss with respect to an "optimal" method is also presented. Several other novelties, with respect to other wide-parameter analysis pipelines, are also outlined. They concern, in particular, the construction of the grid in the parameter space, with over-resolution in frequency and parameter refinement, candidate selection and various data cleaning steps which are introduced to improve search sensitivity and rejection of false candidates.Comment: 27 pages, 20 figures, PRD in pres

Serviço Social e Justiça Restaurativa

TCC (Graduação) - Universidade Federal de Santa Catarina. Centro Socioeconômico. Serviço Social.A Justiça Restaurativa surge para responder as demandas que a Justiça Tradicional não consegue atender em sua totalidade, além e ser uma das consequências do alargamento jurisdicional decorrente da globalização econômica (FARIA, 2001). Atua na resolução de conflitos priorizando a autonomia dos sujeitos, respeitando a diversidade e promovendo a horizontalidade nos espaços em que se insere. As primeiras experiências foram realizadas no início dos anos 70 em países da América do Norte, Nova Zelândia e Austrália (ZEHR, 2012). Essa nova proposta de Justiça chegou no Brasil apenas em 2002 na 3ª Vara do Juizado da Infância e Juventude em Porto Alegre. No mesmo ano, a Organização das Nações Unidas – ONU, torna pública a resolução que traz a definição de conceitos relativos à Justiça Restaurativa, balizando o seu uso nos programas mundiais (ONU, 2002). Em 2005, após a Conferência Internacional "Acesso à Justiça por Meios Alternativos de Resolução de Conflitos", são criados três projetos pilotos localizados nas cidades de Porto Alegre – RS, Brasília - DF e São Caetano do Sul – SP. A diferença entre os serviços do sistema de justiça criminal ou penal e a Justiça Restaurativa é que, enquanto o primeiro centra-se na aplicação de castigo aos ofensores, o segundo preocupa-se na satisfação das necessidades das vítimas, comunidade e dos próprios ofensores (ZEHR, 2012). A relação do Serviço Social com a Justiça Restaurativa se dá na medida em que o Poder Judiciário, espaço socioocupacional desta profissão, se apropria desta nova proposta. O trabalho aborda a relação entre o Serviço Social e a Justiça Restaurativa. Para tanto, pauta-se no Código de Ética do assistente social (CFESS, 1993), que baliza e norteia as suas ações