32,315 research outputs found

    Model inspired by population genetics to study fragmentation of brittle plates

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    We use a model whose rules were inspired by population genetics, the random capability growth model, to describe the statistical details observed in experiments of fragmentation of brittle platelike objects, and in particular the existence of (i) composite scaling laws, (ii) small critical exponents \tau associated with the power-law fragment-size distribution, and (iii) the typical pattern of cracks. The proposed computer simulations do not require numerical solutions of the Newton's equations of motion, nor several additional assumptions normally used in discrete element models. The model is also able to predict some physical aspects which could be tested in new experiments of fragmentation of brittle systems.Comment: We have modified the text in order to make the description of the model more clear. One Figure (Figure 1) was introduced showing the steps of the dynamics of colonization. Twelve references were adde

    Filme de animação e realidade aumentada. Desenvolvimento de um recurso de aprendizagem para o 2.º ciclo do ensino básico

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    This article describes the process concerning the development and implementation of educational audio-visual technical resources. The resources were developed using stop-motion animation technique and deployed over a Technological Education (TE) textbook byAugmented Reality (AR) technology. These resources, drawn up in accordance with the principles set out in the Cognitive Theory of Multimedia Learning (TCAM) were made available for a student sample of the 2nd Cycle of basic education in a northern Portuguese public school.The prototypes were subject of a study in threeparts. The first, according to the Development Research methodology, consisted in the usability evaluation of the prototypes. The second, using the Instructional Material Motivation Survey (IMMS) (Keller 2009) based on ARCS motivation model (Keller 1987) intendto study the impact on the motivation of users.The third, using an experimental design (Kumar 2011), involving control and experimental groups, aims to know the impact on student learning achievements. This article presents the first part of the study. Early results suggest that the audio-visual prototypes implemented in the textbook, are easy to use and to learn complying with general usability parameters, and that the AR technology is mature enough to be used in educational contexts.info:eu-repo/semantics/publishedVersio

    Importância da fisioterapia na prevenção e tratamento da pubalgia atlética

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    Projeto de Graduação apresentado à Universidade Fernando Pessoa como parte dos requisitos para obtenção do grau de Licenciado em FisioterapiaIntrodução: A pubalgia atlética é uma patologia complexa, cuja etiologia é ainda questionável e desafiadora, contudo acredita-se que esteja relacionada com desportos que integram rotações imprevisíveis e repentinas. Objetivo: Investigar de que forma diversos protocolos fisioterapêuticos atuam a nível da prevenção e/ou do tratamento da pubalgia atlética. Metodologia: Foi efetuada uma pesquisa nas bases de dados da PubMed, PEDro e Scielo para identificar estudos com procedimentos terapêuticos do fisioterapeuta na pubalgia atlética. A qualidade metodológica dos estudos foi analisada através da escala Critical Appraisal Skills Programme (CASP). Resultados: A presente revisão inclui 5 artigos, 2 referentes à prevenção e 3 à reabilitação, com um total de 1087 atletas, com idades compreendidas entre 18 e 50 anos. Após a implementação de diversas técnicas terapêuticas verificou-se uma redução no tempo de retorno à atividade desportiva. O risco lesivo aumenta com a reincidência de lesões e com níveis competitivos superiores, assim como com a presença de desequilíbrios musculares entre adutores e abdutores. Conclusão: Com base nos estudos analisados, o fisioterapeuta deve atuar utilizando o tratamento multimodal, tendo também como opções o exercício terapêutico, e o tratamento passivo, embora com menor benefícios.Introduction: Athletic pubalgia is a complex pathology whose etiology is still questionable and challenging, but it is believed to be related to sports that integrate sudden and unexpected rotations. Objective: To investigate how various physiotherapeutic protocols act in the prevention and/or treatment of athletic pubalgia Methodology: Research in PubMed, PEDro and Scielo to identify studies with therapeutic procedures of physiotherapy in athletic pubalgia. The methodological quality of the studies was analyzed through the Critical Appraisal Skills Program (CASP). Results: The present review includes 5 articles, 2 referring to prevention and 3 to rehabilitation, with a total of 1087 athletes, aged between 18 and 50 years. After the implementation of several therapeutic techniques there was a reduction in the time of return to the sport activity. The risk of injury increases with the recurrence of lesions and with higher competitive levels, as well as the presence of muscular imbalances between adductors and abductors. Conclusion: Based on the studies analyzed, the physiotherapist should act using multimodal treatment, also having in mind options such as the therapeutic exercise, and passive treatment, although with less benefits.N/

    Little-Parks oscillations near a persistent current loop

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    We investigate the Little-Parks oscillations caused by a persistent current loop set on the top edge of a mesoscopic superconducting thin-walled cylinder with a finite height. For a short cylinder the Little-Parks oscillations are approximately the same ones as the standard effect, as there is only one magnetic flux piercing the cylinder. For a tall cylinder the inhomogeneity of the magnetic field makes different magnetic fluxes pierce the cylinder at distinct heights and we show here that this produces two distinct Little-Parks oscillatory regimes according to the persistent current loop. We show that these two regimes, and also the transition between them, are observable in current measurements done in the superconducting cylinder. The two regimes stem from different behavior along the height, as seen in the order parameter, numerically obtained from the Ginzburg-Landau theory through the finite element methodComment: 13 pages, 12 figure

    The crossroads between infection and bone loss

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    Bone homeostasis, based on a tight balance between bone formation and bone degradation, is affected by infection. On one hand, some invading pathogens are capable of directly colonizing the bone, leading to its destruction. On the other hand, immune mediators produced in response to infection may dysregulate the deposition of mineral matrix by osteoblasts and/or the resorption of bone by osteoclasts. Therefore, bone loss pathologies may develop in response to infection, and their detection and treatment are challenging. Possible biomarkers of impaired bone metabolism during chronic infection need to be identified to improve the diagnosis and management of infection-associated osteopenia. Further understanding of the impact of infections on bone metabolism is imperative for the early detection, prevention, and/or reversion of bone loss. Here, we review the mechanisms responsible for bone loss as a direct and/or indirect consequence of infection.This article is a result of the project HEALTH-UNORTE: Setting-up biobanks and regenerative medicine strategies to boost research in cardiovascular, musculoskeletal, neurological, oncological, immunologicalm, and infectious diseases (NORTE-01-0145-FEDER-000039), supported by Norte Portugal Regional Operational Programme (NORTE 2020), under the PORTUGAL 2020 Partnership Agreement, through the European Regional Development Fund (ERDF). A.C.G. is supported by a Junior Investigator Contract under the program CEEIND2017, from Fundação para a Ciência e Tecnologia (Portugal)
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