Universidade Federal de Minas Gerais

About: Universidade Federal de Minas Gerais is a education organization based out in Belo Horizonte, Minas Gerais, Brazil. It is known for research contribution in the topics: Population & Immune system. The organization has 41631 authors who have published 75688 publications receiving 1249905 citations.

Hierarchy of Hofstadter states and replica quantum Hall ferromagnetism in graphene superlattices

Abstract: Graphene on boron nitride gives rise to a moire superlattice displaying the Hofstadter butterfly: a fractal dependence of energy bands on external magnetic fields. Now, by means of capacitance spectroscopy, further aspects of this system are revealed—most notably, suppression of quantum Hall antiferromagnetism at particular commensurate magnetic fluxes.

The Bambuí health and ageing study (BHAS): methodological approach and preliminary results of a population-based cohort study of the elderly in Brazil.

Abstract: OBJETIVO: Um estudo de coorte esta sendo desenvolvido para identificar fatores preditores de eventos adversos a saude em idosos Sao apresentados a metodologia do estudo e os resultados descritivos preliminares METODOS: A populacao estudada e constituida por todos os residentes na cidade de Bambui, Minas Gerais, com 60 ou mais anos de idade (n=1742) Destes, 92,2% foram entrevistados e 85,9% foram submetidos a exames hematologicos e bioquimicos, sorologia para Trypanosoma cruzi , medidas antropometricas e de pressao arterial e eletrocardiograma Aliquotas de soro, plasma e DNA foram estocadas para futuras investigacoes A entrevista da linha de base do estudo incluiu: caracteristicas sociodemograficas, percepcao da saude e morbidade auto-referida, uso de medicamentos, acesso a servicos de saude e a planos de saude, atividades fisicas, uso de fumo e de alcool, habitos alimentares, historia reprodutiva, funcao fisica, eventos da vida, recursos sociais e saude mental Os participantes estao sendo acompanhados anualmente RESULTADOS: As seguintes caracteristicas predominaram entre os participantes: mulheres (60%), casados (48,9%) ou viuvos (35,4%), residentes em domicilios com ate 2 pessoas (73,8%), chefes de familia (76,7%), pessoas com renda mensal entre 1 e 2,99 salarios-minimos (62%) e pessoas com 4 ou menos anos de escolaridade (89,1%) A mediana da idade foi igual a 68 anos Somente 1,7% dos membros da coorte foram perdidos no primeiro acompanhamento CONCLUSOES: Em geral, as caracteristicas da populacao estudada foram muito semelhantes as de participantes de outros estudos epidemiologicos sobre envelhecimento, desenvolvidos em grandes cidades brasileiras A pequena perda para acompanhamento mostra que a escolha de Bambui foi adequada, garantindo a viabilidade de um estudo prospectivo de longa duracao

A Unified Game-Theoretic Approach to Multiagent Reinforcement Learning

Abstract: To achieve general intelligence, agents must learn how to interact with others in a shared environment: this is the challenge of multiagent reinforcement learning (MARL). The simplest form is independent reinforcement learning (InRL), where each agent treats its experience as part of its (non-stationary) environment. In this paper, we first observe that policies learned using InRL can overfit to the other agents' policies during training, failing to sufficiently generalize during execution. We introduce a new metric, joint-policy correlation, to quantify this effect. We describe an algorithm for general MARL, based on approximate best responses to mixtures of policies generated using deep reinforcement learning, and empirical game-theoretic analysis to compute meta-strategies for policy selection. The algorithm generalizes previous ones such as InRL, iterated best response, double oracle, and fictitious play. Then, we present a scalable implementation which reduces the memory requirement using decoupled meta-solvers. Finally, we demonstrate the generality of the resulting policies in two partially observable settings: gridworld coordination games and poker.

Role of Microglia TLRs in Neurodegeneration.

Abstract: Toll-like receptors (TLRs) are a group of receptors widely distributed in the organism. In the central nervous system, they are expressed in neurons, astrocytes, and microglia. Although their involvement in immunity is notorious, different papers have demonstrated their roles in physiological and pathological conditions, including neurodegeneration. There is increasing evidence of an involvement of TLRs, especially TLR2, 4, and 9 in neurodegenerative diseases such as Alzheimer’s disease (AD), Parkinson’s disease (PD), and amyotrophic lateral sclerosis (ALS). In this sense, their expression in microglia might modulate the activity of these cells, which in turn, lead to protective or deleterious effects over neurons and other cells. Therefore, TLRs might mediate the link between inflammation and neurodegenerative diseases. However, further studies have to be performed to elucidate the role of the other TLRs in these diseases and to further prove and confirm the pathophysiological role of all TLRs in neurodegeneration. In this paper, we revise and summarize the current knowledge regarding the role of TLRs in neurodegeneration with the focus on the possible functions of these receptors in microglia.

A transição da estrutura etária da população brasileira na primeira metade do século XXI

Abstract: A trajetoria da populacao brasileira, na primeira metade deste seculo, tanto em termos de seu volume, quanto de sua estrutura etaria, ja esta praticamente definida, pois, tanto a transicao de mortalidade quanto a da fecundidade ja se encontram muito avancadas. Enquanto a populacao idosa (65 e mais anos de idade) aumentara a taxas altas (entre 2% e 4% ao ano), a populacao jovem tendera a decrescer. Segundo projecoes das Nacoes Unidas, de 3,1% da populacao total, em 1970, a populacao idosa brasileira devera passar a aproximadamente 19%, em 2050. Paralelamente, conviverao dentro das populacoes jovem e adulta subgrupos etarios com crescimento negativo e positivo. A transicao etaria brasileira gera oportunidades e desafios que, se nao aproveitados e enfrentados, no momento devido, levara o pais a seriissimos problemas, nas proximas decadas.