2,146 research outputs found

    Nonequilibrium Phase Transition in the Kinetic Ising model: Critical Slowing Down and Specific-heat Singularity

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    The nonequilibrium dynamic phase transition, in the kinetic Ising model in presence of an oscillating magnetic field, has been studied both by Monte Carlo simulation and by solving numerically the mean field dynamic equation of motion for the average magnetisation. In both the cases, the Debye 'relaxation' behaviour of the dynamic order parameter has been observed and the 'relaxation time' is found to diverge near the dynamic transition point. The Debye relaxation of the dynamic order parameter and the power law divergence of the relaxation time have been obtained from a very approximate solution of the mean field dynamic equation. The temperature variation of appropiately defined 'specific-heat' is studied by Monte Carlo simulation near the transition point. The specific-heat has been observed to diverge near the dynamic transition point.Comment: Revtex, Five encapsulated postscript files, submitted to Phys. Rev.

    AVALIAÇÃO DA SUSTENTABILIDADE EM EDIFICAÇÕES ANTÁRTICAS NOS ASPECTOS REFERENTES À QUALIDADE DO AMBIENTE INTERNO

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    Habitar a Antártica significa superar uma série de severos fatores locais, estando a produção arquitetônica absolutamente condicionada às condições ambientais. Com o passar dos anos, essas dificuldades foram sendo vencidas concomitantemente ao avanço da tecnologia. Entretanto, além do esforço para o enfrentamento das condições adversas particulares ao continente, existe também a necessidade de um esforço de adaptação harmônica do homem com o ambiente. As baixas temperaturas, rajadas de vento, isolamento e a necessidade de preservação do ambiente natural delegam à arquitetura a busca por soluções sustentáveis e que garantam a proteção e condições de conforto adequada aos seres humanos. Assim, o objetivo do trabalho é aprimorar e propor a metodologia dos indicadores de avaliação de sustentabilidade para edificações antárticas desenvolvido por Montarroyos (2015), com foco nos aspectos concernentes às questões da qualidade do ambiente interno, visando atender a lacuna existente na área de conforto no ambiente antártico. Objetiva-se que os indicadores sirvam, também, para orientar os projetistas na etapa de projetos, promovendo uma arquitetura que integre as questões referentes a sustentabilidade e a qualidade do ambiente interno. Para o alcance dos objetivos propostos, os procedimentos metodológicos adotados dividiram-se em cinco etapas. Primeiramente foi feita a revisão bibliográfica dos aspectos concernentes à pesquisa, o que permitiu a definição dos critérios contemplados e limites da avaliação. Em seguida, foi desenvolvido para cada indicador as marcas de referência e seus respectivos pesos e, por fim, análise dos resultados e obtenção do conjunto final de indicadores de conforto. O resultado das análises permitiu a proposição de uma metodologia flexível para a ponderação dos indicadores referentes não só à qualidade do ambiente interno, mas para os aspectos gerais que englobam edificações antárticas. Palavras-chave: Antártica, indicadores, conforto, qualidade do ambiente interno

    A three-step approach to post-fire mortality modelling in maritime pine (Pinus pinaster Ait.) stands for enhanced forest planning in Portugal

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    Maritime pine (Pinus pinaster Ait) is a very important timber-producing species in Portugal with a yield of ~67.1 million m3 year21. It covers ~22.6 per cent of the forest area (710.6 × 103 ha). Fire is the most significant threat to maritime pine plantations. This paper discusses research aiming at the development of post-fire mortality models for P. pinaster Ait stands in Portugal that can be used for enhanced integration of forest and fire management planning activities. Post-fire mortality was modelled using biometric and fire data from 2005/2006 National Forest Inventory plots and other sample plots within 2006–2008 fire perimeters. A three-step modelling strategy based on logistic regression methods was used. Firstly, the probability of mortality to occur after a wildfire in a stand is predicted and secondly, the degree of mortality caused by a wildfire on stands where mortality occurs is quantified. Thirdly, mortality is distributed among trees. The models are based on easily measurable tree characteristics so that forest managers may predict post-fire mortality based on forest structure. The models show that relative mortality decreases when average d.b.h. increases, while slope and tree size diversity increase the mortalityinfo:eu-repo/semantics/publishedVersio

    Nonequilibrium phase transition in the kinetic Ising model: Is transition point the maximum lossy point ?

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    The nonequilibrium dynamic phase transition, in the kinetic Ising model in presence of an oscillating magnetic field, has been studied both by Monte Carlo simulation (in two dimension) and by solving the meanfield dynamical equation of motion for the average magnetization. The temperature variations of hysteretic loss (loop area) and the dynamic correlation have been studied near the transition point. The transition point has been identified as the minimum-correlation point. The hysteretic loss becomes maximum above the transition point. An analytical formulation has been developed to analyse the simulation results. A general relationship among hysteresis loop area, dynamic order parameter and dynamic correlation has also been developed.Comment: 8 pages Revtex and 4 Postscript figures; To appear in Phys. Rev.

    InfoFaunaFVG: a novel progressive web application for wildlife surveillance

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    The Department of Agricultural, Food, Environmental and Animal Sciences (DI4A) at the University of Udine, in collaboration with Friuli Venezia Giulia regional authorities, within northeastern Italy, set up a wildlife monitoring and surveillance regional network, named InfoFaunaFVG. Here we describe the development and application of this data repository system based on a novel progressive web application, and report the data gathered in the first two and a half years of its use. InfoFaunaFVG is made of a Web Database and an integrated WebGIS system. In particular, the following open source softwares are used: Apache HTTP Server, Oracle MySQL, Symfony, Apache Tomcat, GeoServer, OpenLayers. The web app can be accessed from any web browser or by installing the progressive web application in the desktop or mobile devices. In short, operating from November 2019, InfoFaunaFVG currently (April 2022) contains a total of 40,175 records, from 300 different users, from 16 institutions. Among all species recorded, mammals were 40% (16,018) of the total, whereas avian species represented 59% (23,741), and others (reptiles and amphibians) 1% (416), respectively. Two hundred twenty-six different species (175 avian and 51 mammals) were recorded. Details about causes of death and live animal rescue were reported. To date, InfoFaunaFVG has proven to be a successful wildlife data repository system providing high quality consistent, accurate and traceable data. These had a considerable impact on regional wildlife governance. In the authors’ knowledge, InfoFaunaFVG is the first example described in literature of such a progressive web application, coordinated on an institutional level, and not based on voluntary-citizen observations. InfoFaunaFVG has the potential to become the largest wildlife monitoring and surveillance data repository system on a national level

    Adult-Acquired Flatfoot Deformity and Age-Related Differences in Foot and Ankle Kinematics During the Single-Limb Heel-Rise Test

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    STUDY DESIGN: Cross-sectional laboratory study. OBJECTIVE: To compare single-limb heel-rise performance and foot-ankle kinematics between persons with stage 2 adult-acquired flatfoot deformity (AAFD) and healthy controls. BACKGROUND: The inability to perform a single-limb heel rise is considered a positive functional diagnostic test for AAFD. However, which foot motions contribute to poor performance of this task are not known. METHODS: Fifty individuals participated in this study, 20 with stage 2 AAFD (mean +/- SD age, 57.6 +/- 11.3 years), and 15 older participants (age, 56.8 +/- 5.3 years) and 15 younger participants (age, 22.2 +/- 2.4 years) without AAFD as control groups. Forefoot (sagittal plane) and rearfoot (sagittal and frontal planes) kinematics were collected using a 3-D motion analysis system. Heel-rise performance (heel height) and kinematics (joint angles, excursions) were evaluated. One-way and 2-way analyses of variance were used to examine differences in heel-rise performance and kinematics between groups. RESULTS: Individuals with AAFD and older controls demonstrated lower heel-rise height than those in the younger control group (P\u3c.001). Persons with AAFD demonstrated higher degrees of first metatarsal dorsiflexion (P\u3c.001), lower ankle plantar flexion (P\u3c.001), and higher subtalar eversion (P = .027) than those in the older control group. Persons with AAFD demonstrated lower ankle excursion (P\u3c.001) and first metatarsal excursion (P\u3c.001) than those in the older control group, but no difference in subtalar excursion (P = .771). CONCLUSION: Persons with stage 2 AAFD did not achieve sufficient heel height during a single-leg heel rise. Both forefoot and rearfoot kinematics in the sagittal plane, as opposed to the frontal plane, contributed to the lower heel height in participants with stage 2 AAFD. Older controls demonstrated lower heel-rise height than younger controls, indicating that clinical expectations of heel-rise performance may need to be adjusted for age
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