Bose-Einstein condensation in an optical lattice: A perturbation approach

We derive closed analytical expressions for the order parameter $\Phi (x)$ and for the chemical potential $\mu$ of a Bose-Einstein Condensate loaded into a harmonically confined, one dimensional optical lattice, for sufficiently weak, repulsive or attractive interaction, and not too strong laser intensities. Our results are compared with exact numerical calculations in order to map out the range of validity of the perturbative analytical approach. We identify parameter values where the optical lattice compensates the interaction-induced nonlinearity, such that the condensate ground state coincides with a simple, single particle harmonic oscillator wave function

Abordagem integradora para implementação de um sistema de gestão de segurança e impactos de visitação em áreas naturais protegidas

A gestão de visitação em áreas protegidas age em duas frentes, em geral desconexas: a social e a biofísica. Na prática, a dicotomia entre gestão de segurança e de impactos da visitação transparece no uso de ferramentas díspares que inibe uma ou outra de acordo com a visão e capacitação das equipes envolvidas. Este trabalho propõe sistematizar uma visão integradora onde a qualidade da experiência da visitação, do ponto de vista da segurança da atividade, e as alterações ambientais diretas ou indiretas subsequentes possam ser ponderadas, avaliadas e geridas simultaneamente dentro de um Sistema de Gestão de Segurança e Impactos.The management of visitation in protected areas acts on two fronts, in general, disconnected: social and biophysical. In practice, the dichotomy between impact and safety managements, using disparate tools, inhibits one or another tool according to the vision and capacity of the management teams. This work aims to systematize an integrative vision where the quality of the visitation experience and the subsequent direct or indirect environmental changes can be weighted, evaluated and managed simultaneously within a Security and Impact Management System.La gestión de visitas en áreas protegidas actúa en dos frentes, generalmente desconectados: el social y el biofísico. En la práctica, la dicotomía entre la gestión de seguridad y los impactos de las visitas se refleja en el uso de herramientas dispares que inhiben una u otra según la visión y formación de los equipos implicados. Este trabajo propone sistematizar una visión integradora donde la calidad de la experiencia de visita, desde el punto de vista de la seguridad de la actividad, y los posteriores cambios ambientales directos o indirectos puedan ser considerados, evaluados y gestionados simultáneamente dentro de un Sistema de Gestión de Seguridad e Impactos

THE PREVALENCE AND CAUSE OF NON-CONTACT INJURY MECHANISMS IN U.S. MEN’S RUGBY-7S

The aim of this study was to prospectively report non-contact injury incidence and causes in U.S. men’s Rugby-7s players (n=446) over 2010-2015, using the Rugby Injury Survey & Evaluation (RISE) methodology. Non-contact injuries (time-loss 25%; medical attention 75%) had higher rates among backs (62%; 28.4/1000ph) than forwards (38%; 23.2/1000ph; RR:1.22; p=0.05). Non-contact injuries resulted in an average of 48.7days (d) absence from sport (classic non-contact 48.1d; other non-contact 77.0d). Acute injuries (85%) were most common during attempts to elude a tackle (31%) and in running/open play (48% overall; from 35% in 2010, 41% in 2011, 52% in 2012, 43% in 2013, 46% in 2014, 70% in 2015). Most non-contact injuries (44%) occurred during the first two tournament matches. These results provide much needed data on Rugby-7s, impacting emerging countries

THE INCIDENCE AND NATURE OF NON-CONTACT INJURIES IN U.S. WOMEN’S RUGBY-7S

The aim of this study was to prospectively determine non-contact injury incidence and mechanisms among U.S. amateur women’s Rugby-7s. Non-contact injuries occurred frequently among the U.S. women population (26.5/1000ph; 29% of all injuries; n=167). The incidence of non-contact injuries occurred at similar rates among backs (58%, 23.9/1000ph, CI:19.1-29.6) and forwards (42%, 19.3/1000ph, CI:14.4-25.3; RR:1.04, p=0.816). Non-contact injuries resulted in 58.4 mean days absence from play. This study demonstrates a greater proportion of match injuries among U.S. amateur women Rugby-7 participants were related to non-contact mechanism when compared to International women participants. Therefore, U.S. women Rugby-7 players would benefit from prevention programs to minimize non-contact injury risks

USA WOMENS RUGBY SEVENS CONTACT INJURY RISK FACTORS

The purpose of the study was to identify the rates and causes of contact injuries in U.S. women’s Rugby-7s tournament players (2010-2015) and present guidelines for injury prevention to reduce the risk of injury in this emerging female contact-sport athlete. Data were captured using the Rugby Injury Survey & Evaluation (RISE) methodology. Contact injuries were frequent over the study period (direct=56%; indirect=38%, unknown=6%). Contact injuries overall were similar among positions (

BIOMECHANICAL CONTACT INJURY INFLUENCES IN USA MENS RUGBY-7S

The aim of this study was to prospectively report injury incidence and contact mechanisms in U.S. men’s under-19 to elite Rugby-7s players (n=852) over 2010-2015, using the Rugby Injury Survey & Evaluation (RISE) methodology. Contact injuries occurred with frequency (Overall, including time-loss and medical attention=55.4/1000ph; time-loss=17.2/1000ph;

Photocurrent-voltage relation of resonant tunneling diode photodetectors

We have investigated photodetectors based on an AlGaAs/GaAs double barrier structure with a nearby lattice-matched GaInNAs absorption layer. Photons with the telecommunication wavelength λ = 1.3 µm lead to hole accumulation close to the double barrier inducing a voltage shift ΔV(V) of the current-voltage curve, which depends strongly on the bias voltage V. A model is proposed describing ΔV(V) and the photocurrent response in excellent agreement with the experimental observations. According to the model, an interplay of the resonant tunneling diode (RTD) quantum efficiency ƞ(V), the lifetime of photogenerated and accumulated charge carriers τ(V), and the RTD current-voltage relation in the dark determines best working parameters of RTD photodetectors. Limitations and voltage dependencies of the photoresponse are discussed

Evidence for the formation of metallic In after laser irradiation of InP

Structural and electronic changes induced by laser irradiation are currently of interest owing to the possibility to tune the mechanical, optical, and transport properties of the irradiated materials. In this work, we investigate the effects of laser irradiation on indium phosphide, InP, by modifying the electronic temperature, Te, of the system within the density functional theory framework and performing molecular dynamics simulations to prove that the laser irradiation also provokes a local thermalization effect. We found that the process can be described by a two-stage mechanism. First, at low Te values (0–1.0 eV), the laser energy induces electronic transitions, while the InP lattice remains undisturbed and cool. In the second stage (with Te in the range of 1.0–4.0 eV), both electron-electron scattering and electron-phonon coupling processes are triggered, increasing the energy of the lattice so as to provoke a Coulomb explosion, which changes some physical chemical properties of InP. The close agreement between the simulations helps explain the formation of metallic In as it is observed in the transmission electron microscopy images

Circular polarization in a non-magnetic resonant tunneling device

We have investigated the polarization-resolved photoluminescence (PL) in an asymmetric n-type GaAs/AlAs/GaAlAs resonant tunneling diode under magnetic field parallel to the tunnel current. The quantum well (QW) PL presents strong circular polarization (values up to -70% at 19 T). The optical emission from GaAs contact layers shows evidence of highly spin-polarized two-dimensional electron and hole gases which affects the spin polarization of carriers in the QW. However, the circular polarization degree in the QW also depends on various other parameters, including the g-factors of the different layers, the density of carriers along the structure, and the Zeeman and Rashba effects