Chaos and Synchronized Chaos in an Earthquake Model

We show that chaos is present in the symmetric two-block Burridge-Knopoff model for earthquakes. This is in contrast with previous numerical studies, but in agreement with experimental results. In this system, we have found a rich dynamical behavior with an unusual route to chaos. In the three-block system, we see the appearance of synchronized chaos, showing that this concept can have potential applications in the field of seismology.Comment: To appear in Physical Review Letters (13 pages, 6 figures

Características físico-químicas, microbiológicas e aceitabilidade de iogurte de leite de búfala para merenda escolar.

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Abordagem multi-física ao comportamento em serviço das estruturas de betão: monitorização dos campos intermos de humidade

No âmbito do projeto de investigação denominado SeLCo – “Comportamento em serviço de estruturas de betão: uma abordagem multi-física das tensões autoinduzidas” – está a ser realizado um conjunto de trabalhos conducentes ao estabelecimento de abordagens de simulação higro-mecânica para estudo do carácter não uniforme das tensões associadas à retração de secagem em estruturas de betão armado. De facto, a secagem do betão ocorre de forma progressiva da superfície para o interior, originando deformações impostas. Para que possam ser simuladas as tensões decorrentes destes processos é primeiramente necessário dispor de modelos capazes de simular os campos de humidade, devidamente fundamentados em resultados obtidos através de medições experimentais. O presente artigo dedica atenção ao último aspeto, apresentando um conjunto de trabalhos realizados com o intuito de melhor compreender os desafios envolvidos na monitorização da humidade interna no betão. Apesar de haver vários trabalhos na bibliografia relativamente a este assunto, são escassos os que comparam o desempenho de metodologias e sensores para medição da humidade interna no betão. Neste trabalho são apresentados vários conjuntos de experiências que comparam o desempenho de sensores e de procedimentos de monitorização, explanando-se as principais ilações e estratégias a adotar no contexto do programa experimental a conduzir no âmbito da investigação sobre tensões autoinduzidas no betão

Mapeamento de áreas cafeeiras do Sul de Minas Gerais - Machado e Três Pontas.

O objetivo deste trabalho foi mapear as áreas cafeeiras das regiões de Machado e Três Pontas no Sul do Estado de Minas Gerias, no Brasil, usando sensoriamento remoto. A Interpretação visual das imagens do satélite Landsat/TM foi utilizada para obter os mapas preliminares das áreas cafeeiras. Estes mapas foram conferidos em campo e utilizados posteriormente para avaliar a performance da inicial classificação supervisionada. Os mapas preliminares e corrigidos de ambas as regiões foram comparados e a acurácia foi avaliada através dos índices Kappa e Global obtidos pela tabela de concordância. Os resultados mostraram uma acurácia de 97%(Global) e 95%(Kappa) para a região de Machado e 99%(Global) e 98%(Kappa) para Três Pontas. As diferenças são pequenas, os resultados mostram a influencia da topografia de Três Pontas, com declividades suaves e uniformidade das áreas cafeeiras, na classificação. Os resultados mostram que o sensoriamento remoto apresentou grande precisão e um alto grau de concordância, possibilitando minimizar o tempo e o custo para o planejamento sustentável da cafeicultura destas importantes regiões de Minas Gerais

Avalanches in the Weakly Driven Frenkel-Kontorova Model

A damped chain of particles with harmonic nearest-neighbor interactions in a spatially periodic, piecewise harmonic potential (Frenkel-Kontorova model) is studied numerically. One end of the chain is pulled slowly which acts as a weak driving mechanism. The numerical study was performed in the limit of infinitely weak driving. The model exhibits avalanches starting at the pulled end of the chain. The dynamics of the avalanches and their size and strength distributions are studied in detail. The behavior depends on the value of the damping constant. For moderate values a erratic sequence of avalanches of all sizes occurs. The avalanche distributions are power-laws which is a key feature of self-organized criticality (SOC). It will be shown that the system selects a state where perturbations are just able to propagate through the whole system. For strong damping a regular behavior occurs where a sequence of states reappears periodically but shifted by an integer multiple of the period of the external potential. There is a broad transition regime between regular and irregular behavior, which is characterized by multistability between regular and irregular behavior. The avalanches are build up by sound waves and shock waves. Shock waves can turn their direction of propagation, or they can split into two pulses propagating in opposite directions leading to transient spatio-temporal chaos. PACS numbers: 05.70.Ln,05.50.+q,46.10.+zComment: 33 pages (RevTex), 15 Figures (available on request), appears in Phys. Rev.

A Patient Perception as a Nursing Care in Emergency Sector

The work process by nurses in the emergency sector is comprised of two complementary dimensions, managing and caring. Therefore,the aim of this study was Know the perception of patients to the support of the nursing assistance in Emergency sector. This is a field research, exploratory, descriptive qualitative approach. The survey was conducted in Dr. Luiz Milton Arêa Leão Hospital - Satélite, located in the city of Teresina - PI, Brazil, which caters exclusively by the Unified Health System, and reference in its coverage area.We interviewed thirteen (13) patients who remained in observation in the emergency sector in that hospital. For this study was used as a criterion for inclusion of service users who entered the emergency sector in the periodMarch-April 2014 and who remained in the sector at the time of the interview.  A pilot test was conducted with the instrument to validate and suitability for the target audience, which is excluded from the sample. Ethical aspects were respected, as provided for in Resolution 466/2012 of the National Health Council, Brazil (2013). In this sense, we observed through the reports of the participants carrying out a qualified nursing care, where it identified a good conduct of professionals to provide the necessary assistance. A nursing care and systematic termination  during the stay of patients in hospital was evidenced. It is perceived  that there is a satisfaction from patients and the care of thenursing team, which is performed through actions inherent to these professionals, such as goodwill, the act of providing a welcoming atmosphere, with technical scientific background, and ability in dealing with conflict situations and ethical

Morphophysiological responses of Setaria viridis to cold stress.

ABSTRACT - The objective of this work was to determine the suitability of Setaria viridis as a model plant in studies to validate candidate genes for cold tolerance by evaluating the response of two of its accessions to different durations of abrupt or gradual cold stress in the vegetative and reproductive stages. Plants of accessions A10.1 and Ast-1, cultivated at 25°C, were subjected to the following cold stress treatments: gradual reduction in temperature from 25 to 0°C, 5°C at a time, every 24 hours in a same chamber; or abrupt reduction in temperature, by transferring plants from a chamber at 25°C to another at 0°C. Plants were kept at 0°C for 3, 5, or 10 days, after which temperature was increased back again to 25°C; a control group remained at 25ºC. Low temperatures ? reduced abruptly or gradually ? caused a decrease in the gas exchange rates and shoot and root biomass of the plants, besides damage to their photochemical apparatus; the longer the cold lasted, the more pronounced the effect was. Regardless of stress duration, plants recovered and completed their life cycle. The studied accessions are tolerant to cold and, therefore, are not suitable as a model plant in studies to validate candidate genes for cold tolerance. RESUMO - O objetivo deste trabalho foi determinar a adequação de Setaria viridis como planta modelo em estudos de validação de genes candidatos à tolerância ao frio, ao avaliar a resposta de dois de seus acessos a diferentes durações de estresse por frio abrupto ou gradual, nas fases vegetativa e reprodutiva. Plantas dos acessos A10.1 e Ast-1, cultivadas a 25°C, foram submetidas aos seguintes tratamentos de estresse por frio: redução gradual da temperatura de 25 a 0°C, 5°C de cada vez, a cada 24 horas, em única câmera; ou redução abrupta da temperatura, pela transferência das plantas de uma câmera a 25°C para outra a 0°C. As plantas foram mantidas a 0°C por 3, 5, ou 10 dias, após os quais a temperatura foi aumentada novamente para 25°C; um grupo controle permaneceu a 25ºC. As baixas temperaturas ? reduzidas gradual ou abruptamente ? causaram redução nas taxas de troca gasosa e na biomassa da parte aérea e da raiz das plantas, além de prejuízos ao seu aparato fotoquímico; quanto mais o frio durou, mais pronunciado o efeito foi. Independentemente da duração do estresse, as plantas se recuperaram e completaram seu ciclo de vida. Os acessos estudados são tolerantes ao frio, e, portanto, não são adequados como planta modelo em estudos para validação de genes candidatos de tolerância ao frio.Título em português: Respostas morfofisiológicas de Setaria viridis ao estresse por frio

Influence of cooling methods on the residual mechanical behavior of fire-exposed concrete : an experimental study.

This work reports the main conclusions of a study on the mechanical behavior of concrete under ISO 834 fire with different cooling methods. The aim of this research was to provide reliable data for the analysis of structures damaged by fire. The experimental program used cylindrical concrete test specimens subjected to ISO 834 heating in a furnace up to maximum gas temperatures of 400, 500, 600, 700, and 800 ?C. The compressive strength was measured in three situations: (a) at the different temperature levels reached in the furnace; (b) after a natural cooling process; and (c) after aspersion with water at ambient temperature. The results indicate that the concrete residual compressive strength is fairly dependent on the maximum temperature reached in the furnace and revealed that concrete of a lower strength preserved relatively higher levels of strength. The cooling method significantly influenced the strength, albeit at a lower intensity. In all cases, the residual strength remained in the range of 38% to 67% of the strength at ambient temperature. The statistical analysis showed that the data obtained by the experimental program are significant and confirmed the influence of the conditions imposed on the residual strength