Numerical Simulations of the Magnetodielectric response in Ising Pyrochlores

In this paper, we examine the magnetoelectric response of Ising pyrochlores, focusing on both the ordered antiferromagnetic state and the frustrated ferromagnetic case known as "spin-ice". We employ a model which accounts for magnetoelastic effects by considering the interplay between oxygen distortions and superexchange magnetic interactions within pyrochlores. This, together with numerical simulations, provides a tool to make quantitative comparisons with experiments. Our main target is then to see how to extract relevant information from this simple model, and to explore its limitations. We obtain a direct estimation of quantities such as the electric dipole moment, the central oxygen displacement and the effective magnetoelastic energy for the canonical spin-ice material \DTO. We also inquire about the possibility of using the electric dipole carried by magnetic monopoles to obtain a direct measure of their density. In each studied scenario the correlations between monopoles, induced by their number or by the magnetic background,renders these findings less straightforward than initially anticipated. Furthermore, the coupling between electrical and magnetic degrees of freedom provides additional tools to investigate magnetic order in these systems. As an example of this we discuss the phase diagram of the antiferromagnetic pyrochlore under applied magnetic field along the [111] direction. We find an instance where the phase stability at nonzero temperatures is not dictated by the energy associated with different ground states but (akin to the phenomenon of order-by-disorder) is instead determined by their accessibility to thermal fluctuations

Modelagem computacional e análise do comportamento de células a combustível de membrana polimérica em regime estático e dinâmico de carga

The aim of this work is to give a feedback to the industry on the dynamic and static performance of the PEMFC (Polymer Electrolyte Membrane Fuel Cell / Proton Exchange Membrane Fuel Cell). This philosophy of study is an aid tool that models the fuel-cell to give confidence to the designer and to improve controls on a new prototype before they are assembled. In this work the most important aspects of this new device, used to generate electricity, were carefully studied and implemented in a computer in order to simulate its static and dynamic models when under the influence of a load change. The complete research involved the work to obtain design data, the operating principles for the PEMFC fuel-cell, a computer simulation was also built and finally results of the static and dynamic performance of the model are presented.Dissertação (Mestrado)O objetivo deste trabalho é fornecer informações sobre o desempenho dinâmico e estático da Célula de Combustível de Membrana Polimérica (PEMFC). Com esta filosofia de estudo, foi desenvolvida uma ferramenta auxiliar que modela a célula de combustível considerando seus parâmetros construtivos e operacionais, com a intenção de inserir um grau de certeza para o projetista, e melhorar os projetos de controle de um protótipo antes destes serem montados. Neste trabalho os aspectos mais importantes deste novo equipamento para gerar eletricidade foram cuidadosamente estudados e implementados em computador de forma a simular seus comportamentos estático e dinâmico quando sob a influência de uma variação de carga. A pesquisa completa envolveu o trabalho de obter dados sobre os princípios teóricos eletroquímicos envolvidos e os princípios de operação da célula de combustível com membrana polimérica. A partir disso, uma simulação computacional foi construída e finalmente são apresentados os resultados do desempenho estático e dinâmico do modelo

Implementação de mecanismos de avaliação da participação online: um estudo na plataforma Sapo Campus

Mestrado em Comunicação MultimédiaOs serviços da Web 2.0 têm vindo a ser cada vez mais utilizados no contexto educativo dado o seu potencial na criação e dinamização de comunidades de aprendizagem distribuídas. Devido às suas características, estes serviços potenciam a comunicação entre os membros da comunidade, levando à partilha de informação entre estes. Surge assim o projecto SAPO Campus, que tem como objectivo a criação de uma plataforma integrada de serviços Web 2.0 para instituições de Ensino Superior. Assumindo que a implementação desta metodologia, baseada na construção de uma comunidade de aprendizagem, implica a existência de uma constante participação e interacção entre os membros da comunidade torna-se, então, pertinente efectuar a avaliação da forma como os alunos participam nessa mesma comunidade. Devido a este tipo de avaliação ser uma actividade recente e à existência de dificuldades inerentes à sua aplicação, somos confrontados com a necessidade de fornecer ferramentas que apoiem a actividade de avaliação da participação online dos alunos. No presente estudo é feita a conceptualização e implementação de uma ferramenta, integrada na plataforma SAPO Campus, que permite efectuar a avaliação dos contributos dos alunos. Esta ferramenta foi testada de forma a validar as soluções adoptadas e encontrar pontos de trabalho futuro. Para além disso, é feita ainda a conceptualização de uma ferramenta de visualização dos resultados das avaliações efectuadas e o estudo teórico de uma ferramenta que forneça feedback aos alunos acerca da avaliação da sua participação na comunidade. ABSTRACT: The Web 2.0 services are increasingly being used in educational environment due to their potential in the creation and promotion of distributed learning communities. As a result of their characteristics, these services enhance the communication between community members, leading them to share information. This brings us to the SAPO Campus project which aims to create an integrated Web 2.0 services platform to be applied on Higher Education institutions. Implementing this platform consists in building a learning community which will promote constant participation and interaction amongst its members. It then becomes pertinent to carry out an assessment of how students participate in the community. The assessment of the social interactions within Learning communities poses a great deal of problems given the large amount of data and players involved. As such we are faced with the need to provide tools to support the process of evaluating the students' online participation. In the present study it's made the conceptualization and implementation of a tool, integrated in the SAPO Campus platform, that allows the assessment of students' contributions. This tool was tested to validate the adopted solutions and find points of interest to work with in the future. In addition, it's made the conceptualization of a tool that allows to visualize the assessments' results and a theoretical study of a tool that provides feedback to students about the assessment of their participation in the community

Oral administration of eucalyptol reduces cell migration and pain-like behavior in zymosan-induced arthritis mice

Rheumatoid arthritis (RA) is an inflammatory disease that utilizes nonbiologic and biologic drugs for appropriate disease management. However, high cost, adverse effects, reduced effectiveness, and risk of infection have stimulated the search for safer and more efficacious therapeutic strategies. In the present study, we aimed to evaluate the anti-inflammatory and analgesic properties of eucalyptol in an experimental model of arthritis. Mice were administered zymosan or saline intra-articularly. One hour before the zymosan administration, the mice were treated with oral eucalyptol (200-400 mg/kg) and vehicle. Cell influx, neutrophils, lymphocytes, and monocytes were measured in joint exudates. Joint pain was assessed using paw-pressure tests. Orally administered eucalyptol (200 and 400 mg/kg) significantly reduced cell influx, as well as neutrophils, lymphocytes, and monocytes, when compared with the control. Eucalyptol at a dose of 400 mg/kg significantly reversed joint pain and demonstrated analgesic activity (60%); however, 200 mg/kg failed to alter joint pain. These results indicate that oral eucalyptol promotes anti-inflammatory and analgesic activity in mice subjected to zymosan-induced arthritis

Estágio realizado no Centro de Saúde de Paço de Arcos : programa comunitário PLE2NO : atividade física na osteoartrose

A Osteoartrose (OA) é uma doença reumática crónica com elevado impacto na sociedade afetando a saúde, interferindo na realização das atividades de vida diárias e na qualidade de vida da pessoa. O exercício e a educação do paciente destacam-se como medidas de controlo de sintomas. Os objetivos do estágio curricular foram: adquirir conhecimentos teórico-práticos relacionados com OA, desenvolver competências essenciais à ótima comunicação e liderança com as pessoas e instituições envolvidas e prescrever exercícios adaptados a indivíduos com OA no joelho. O estágio esteve relacionado com o desenvolvimento de uma intervenção: Programa Livre de Educação e Exercício Na Osteoartrose - PLE²NO (programa de três meses de educação e exercício), tendo como principal objetivo: cativar e motivar as pessoas para a prática de exercício; determinar a eficácia na gestão da patologia, e controlo dos sintomas, e verificar a sua efetividade na aptidão física e qualidade de vida de pessoas com OA no joelho. Em suma, esta intervenção mostrou-se uma mais-valia na aquisição de conhecimento e relação interpessoal com a população alvo deste programa.Osteoarthritis (OA) is a chronic rheumatic disease with a high impact on society, affecting health, interfering in the performance of daily life activities and in the person's quality of life. Exercise and patient education stand out as symptom control measures. The objectives of the curricular internship were: to acquire theoretical and practical knowledge related to OA, to develop essential skills for excellent communication and leadership with the people and institutions involved and to prescribe exercises adapted to individuals with OA in the knee. The internship was related to the development of an intervention: Free Education and Exercise Program in Osteoarthritis - PLE²NO (three-month education and exercise program), with the main objective: to captivate and motivate people to exercise; to determine the effectiveness in the management of the pathology, and control of the symptoms, and to verify its effectiveness in the physical fitness and quality of life of people with OA in the knee. In short, this intervention showed a capture of knowledge and interpersonal relationship with the target population of this program

Sustainability assessment of a self-consumption wood-energy chain on small scale for heat generation in central Italy

The sustainability of a small-scale self-consumption wood-energy chain for heat generation in central Italy was analyzed from a technical, economic and energetic point of view. A micro-chain was developed within the CRA-ING farm at Monterotondo (Rome, Italy): The purpose of this system was to produce biomass for supplying a heating plant within the CRA-ING property as a substitute for diesel fuel. A poplar short rotation coppice, established with clones AF2, AF6 and Monviso, fed the micro-chain. The rotation was biennial. The average plantation production (Mgd.m.·ha−1·year−1) was 10.2, with a maximum of 13.53 for the twin-rows AF2 and a minimum of 8.00 for the single-row Monviso. The economic assessment was based on the Net Present Value (NPV) method and the equivalent annuity cost, and found an average saving of 15.60 €·GJ−1 of heat generated by the wood chips heating system in comparison with the diesel heating system over a 10 year lifetime of the thermal power plant. The energy assessment of the poplar plantation, carried out using the Gross Energy Requirements method, reported an energy output/input ratio of 12.3. The energy output/input ratio of the whole micro-chain was 4.5

Knowledge, attitudes and practices of university adolescents about syphilis: a cross-sectional study in the Northeast

OBJECTIVE: To analyze knowledge, attitudes and practices of university adolescents about syphilis. METHODS: Cross-sectional, analytical, census-type study, developed with the universe of adolescents aged 18 and 19 years (n = 598), enrolled in three institutions of higher education in a municipality of Piauí (n = 598), which total 20 courses in the areas of Health Sciences, Applied Social Sciences, Exact and Earth, Engineering and Linguistics, Letters and Art. Data collection occurred from March to May 2019, based on a questionnaire adapted from the Pesquisa de Conhecimentos, Atitudes e Práticas da População Brasileira of 2013 (PCAP – Survey of Knowledge, Attitudes and Practices in the Brazilian Population), consisting of questions related to sociodemographic variables (gender, family arrangement, father’s schooling, mother’s schooling, skin color or race, employment, household income), knowledge, attitude and practice regarding the disease, the last three being classified by scores. The variables that presented p ≤ 0.20 in the bivariate analysis, by Pearson’s chi-square test, were included in three multivariate logistic models, and the outcomes in each model were knowledge, attitude and practice, respectively; remaining at the end those at the level of p < 0.05. RESULTS: Boys have a 39.6% lower chance of having adequate/regular knowledge (ORa = 0.604; 95%CI 0.415–0.878), whereas the highest chances are associated with “living alone, with relatives and friends” (ORa = 4.567; 95%CI 1.417–14.719) and having a very positive/positive attitude (ORa = 6.937; 95%CI 4.562–10.550). Lower chances of an adequate practice are associated with boys (ORa = 0.480; 95%CI 0.301–0.766) and lower father’s schooling (ORa = 0.440; 95%CI 0.241–0.806). CONCLUSION: Most participants’ knowledge and attitude regarding syphilis were not sufficient to the adoption of an adequate sexual practice for the prevention of the disease, showing the need to investigate other variables that may be implicated in this cognitive incoherence.OBJETIVO: Analisar conhecimentos, atitudes e práticas de adolescentes universitários sobre a sífilis. MÉTODOS: Estudo transversal, analítico, do tipo censitário, desenvolvido com o universo de adolescentes de 18 e 19 anos (n = 598), matriculados em três instituições de ensino superior presencial em município do Piauí (n = 598), que juntas totalizam 20 cursos nas áreas de Ciências da Saúde, Sociais Aplicadas, Exatas e da Terra, Engenharias e Linguística, Letras e Arte. A coleta de dados ocorreu de março a maio de 2019, a partir de um questionário adaptado da Pesquisa de Conhecimentos, Atitudes e Práticas da População Brasileira de 2013, do Ministério da Saúde, constituído por perguntas referentes a variáveis sociodemográficas (sexo, idade, arranjo familiar, escolaridade dos pais, cor ou raça, atividade remunerada e renda familiar), conhecimento, atitude e prática em relação à doença, sendo as três últimas classificadas por escores. As variáveis que apresentaram valor de p ≤ 0,20 na análise bivariada, por meio do teste do qui-quadrado de Pearson, foram incluídas em três modelos logísticos multivariados, e os desfechos em cada modelo foram o conhecimento, a atitude e a prática, respectivamente; permanecendo ao final aquelas a nível de p < 0,05. RESULTADOS: O sexo masculino possui chance 39,6% menor de ter conhecimento adequado/regular (ORa = 0,604; IC95% 0,415–0,878), enquanto as maiores chances estão associadas a “morar sozinho, com parentes e amigos” (ORa = 4,567; IC95% 1,417–14,719) e a ter atitude muito positiva/positiva (ORa = 6,937; IC95% 4,562–10,550). Menores chances de prática adequada estão associadas ao sexo masculino (ORa = 0,480; IC95% 0,301–0,766) e à menor escolaridade paterna (ORa = 0,440; IC95% 0,241–0,806). CONCLUSÃO: O conhecimento e a atitude da maioria dos participantes do estudo em relação à sífilis não foram suficientes para adoção de uma prática sexual adequada para a prevenção da doença, revelando a necessidade de se investigar outras variáveis que possam estar implicadas nesta incoerência cognitiva