On the nature of the spin-polarized hole states in a quasi-two-dimensional GaMnAs ferromagnetic layer

A self-consistent calculation of the density of states and the spectral density function is performed in a two-dimensional spin-polarized hole system based on a multiple-scattering approximation. Using parameters corresponding to GaMnAs thin layers, a wide range of Mn concentrations and hole densities have been explored to understand the nature, localized or extended, of the spin-polarized holes at the Fermi level for several values of the average magnetization of the Mn ystem. We show that, for a certain interval of Mn and hole densities, an increase on the magnetic order of the Mn ions come together with a change of the nature of the states at the Fermi level. This fact provides a delocalization of spin-polarized extended states anti-aligned to the average Mn magnetization, and a higher spin-polarization of the hole gas. These results are consistent with the occurrence of ferromagnetism with relatively high transition temperatures observed in some thin film samples and multilayered structures of this material.Comment: 3 page

A educação ambiental em maricá/rj : uma visão de Darwin e do príncipe wied-neuwied no século XIX e nos dias atuais

O presente trabalho tem por objetivo descrever os relatos dos naturalistas, Príncipe Maximiliano de Wied-Newied (1815) e Charles Darwin (1832), em suas viagens pelo Município de Marica/RJ, as ações do município no que se refere às questões ambientais em Escolas no 1° Segmento do Ensino Fundamental. É uma pesquisa qualitativa de caráter exploratório-descritiva acerca da história do Município de Maricá e da legislação vigente no Município. Dados foram levantados através de questionários e entrevistas com professores de escolas municipais. Deve ser estabelecida uma política, por parte dos órgãos públicos, direcionada à preservação do patrimônio cultural e ambiental do Município e aproximando dos alunos as atividades de Educação Ambiental

Международный культурно-академический обмен: опыт личного и научного роста

В этой статье описывается опыт трех студентов, участвовавших в программе международной академической мобильности в рамках специальности Металлургическое машиностроение. Это отчет о пребывании студентов в России в Уральском федеральном университете, который стал возможным благодаря Федеральному университету Оуро Прето (UFOP) и Совету по международным делам (CAINT). Обмен, который проходил с начала февраля до конца июля, стал возможностью для приобретения новых научных, культурных и социальных знаний, в том числе знаний в области бизнеса, экономики и менеджмента. Надеемся на стимулирование специальности «Международная мобильность» на высшем уровне, в виду ее важности для улучшения академического образования и повышения уровня подготовки выпускников из Бразилии путем научного и культурного обмена.This article has objective describe an experience of three students to integrate a program of International Mobility Academic, during the graduate in Metallurgical Engineering. It is an account of students experience at Russia, at Ural Federal University, made possible by Federal University of Ouro Preto – (UFOP) and Coordinating international affairs – (CAINT). The exchange experience, that is preview to have started on February and end on July, had possibility the acquisition of new scientific knowledge, cultural and social, including learning Business, Economic and Management. As a contribution, hope to stimulate and intensify the International Mobility specialty in the ambit of graduate, considering the it important to improvement of academic education and the excellence on superior graduate Brazilian by scientific exchange and culture on exterior

A semiquantitative approach to the impurity-band-related transport properties of GaMnAs nanolayers

We investigate the spin-polarized transport of GaMnAs nanolayers in which a ferromagnetic order exists below a certain transition temperature. Our calculation for the self-averaged resistivity takes into account the existence of an impurity band determining the extended ("metallic" transport) or localized (hopping by thermal excitation) nature of the states at and near the Fermi level. Magnetic order and resistivity are inter-related due to the influence of the spin polarization of the impurity band and the effect of the Zeeman splitting on the mobility edge. We obtain, for a given range of Mn concentration and carrier density, a "metallic" behavior in which the transport by extended carriers dominates at low temperature, and is dominated by the thermally excited localized carriers near and above the transition temperature. This gives rise to a conspicuous hump of the resistivity which has been experimentally observed and brings light onto the relationship between transport and magnetic properties of this material

Primary Intraosseous Squamous Cell Carcinoma of the Mandible: a Case with Atypical Imaging Features

Primary intraosseous squamous cell carcinoma is a rare malignant tumour that exclusively arises within the jaws. Its diagnosis requires an appropriate clinical, imaging and histological correlation. The exclusion of primary oral mucosa lesions and metastatic disease is mandatory. We report an atypical imaging appearance of this uncommon entity, characterized by new bone formation and periosteal reaction that resemble sarcomatous or malignant odontogenic tumours. A comprehensive discussion on the embryological principles of primary intraosseous squamous cell carcinoma is also provided.info:eu-repo/semantics/publishedVersio

Cervical Ganglioneuroma in Pediatric Age: A Case Report

Ganglioneuroma is a rare, benign, non-invasive tumor emerging from the sympathetic system. Of these tumors, only 8% occur in the neck. In this report, we present a case of a 13-year-old girl with a 2-year history of enlarging neck mass. Her only complaint, aside from neck swelling, was dysphagia. Physical and radiological examinations revealed a large mass centered in the right carotid space. A transcervical approach was used to excise the tumor emerging from the sympathetic ganglia. The patient developed temporary Horner's syndrome postoperatively. In a few weeks, she was completely asymptomatic. Histological examination was compatible with ganglioneuroma. Surgical excision is the only definite treatment of cervical ganglioneuroma and is also the only way to confirm the diagnosis. Injury during surgery may result in significant morbidity.info:eu-repo/semantics/publishedVersio

Obtenção de hifomicetos entomopatogênicos a partir de solo de pomares de goiabeira (Psidium guajava L.) no município de Mazagão, AP.

Em virtude dos problemas reconhecidamente associados à utilização de inseticidas químicos para o controle de pragas agrícolas, o desenvolvimento de alternativas a essa prática necessita ser considerada, especialmente se o programa de controle estiver inserido em regiões onde. necessariamente, deve-se garantir o equilíbrio do agroecossistema. Nesse contexto, o emprego de agentes fúngicos de controle biológico, como Metarhizium anisopliae e Beauveria bassiana, pode contribuir significativamente, tendo em vista sua comprovada eficácia de controle, facilidade de produção massal em diversos substratos, ampla adaptação a variadas condições ambientais e, praticamente nenhum efeito deletério sobre o ambiente natural. Dessa maneira, o presente trabalho teve por objetivo isolar e caracterizar morfologicamente hifomicetos entomopatogênicos a partir de solo de pomar de goiabeira no município de Mazagão, AP, os quais, posteriormente, serão avaliados quanto à efetividade no controle de imaturos de moscas-das-frutas no Estado do Amapá. O isolamento foi realizado utilizando-se o meio semi-seletivo desenvolvido por Chase et aI. (1986), o qual possibilitou, nas dosagens utilizadas, a recuperação das espécies B. bassiana e M. anisopliae, especialmente. Os isolados de entomopatógenos obtidos foram purificados por meio da técnica de cultura monospórica e, posteriormente, tiveram sua caracterização cultural e morfológica realizada com base no meio de cultura extrato de malte 2%. Em relação aos isolados do gênero Metarhizium, todos são pertencentes a espécie M. anisopliae var. anisopliae. Após caracterização, os isolados foram multiplicados e preservados em frascos de vidro contendo água destilada estéril. Atualmente, os isolados obtidos estão sendo multiplicados e formulados para a realização de testes de patogenicidade contra imaturos da espécie de mosca-das-frutas Anastrepha striata

Management of hypopharyngeal and laryngeal tumours:a 6-year review

info:eu-repo/semantics/publishedVersio

Evaluation of antioxidant activity of selected Brazilian plants extracts

Numerous diseases are induced by free radicals and it has long been recognized that naturally occurring substances in higher plants have antioxidant activityinfo:eu-repo/semantics/publishedVersio