A biomechanics-based articulation model for medical applications

Computer Graphics came into the medical world especially after the arrival of 3D medical imaging. Computer Graphics techniques are already integrated in the diagnosis procedure by means of the visual tridimensional analysis of computer tomography, magnetic resonance and even ultrasound data. The representations they provide, nevertheless, are static pictures of the patients' body, lacking in functional information. We believe that the next step in computer assisted diagnosis and surgery planning depends on the development of functional 3D models of human body. It is in this context that we propose a model of articulations based on biomechanics. Such model is able to simulate the joint functionality in order to allow for a number of medical applications. It was developed focusing on the following requirements: it must be at the same time simple enough to be implemented on computer, and realistic enough to allow for medical applications; it must be visual in order for applications to be able to explore the joint in a 3D simulation environment. Then, we propose to combine kinematical motion for the parts that can be considered as rigid, such as bones, and physical simulation of the soft tissues. We also deal with the interaction between the different elements of the joint, and for that we propose a specific contact management model. Our kinematical skeleton is based on anatomy. Special considerations have been taken to include anatomical features like axis displacements, range of motion control, and joints coupling. Once a 3D model of the skeleton is built, it can be simulated by data coming from motion capture or can be specified by a specialist, a clinician for instance. Our deformation model is an extension of the classical mass-spring systems. A spherical volume is considered around mass points, and mechanical properties of real materials can be used to parameterize the model. Viscoelasticity, anisotropy and non-linearity of the tissues are simulated. We particularly proposed a method to configure the mass-spring matrix such that the objects behave according to a predefined Young's modulus. A contact management model is also proposed to deal with the geometric interactions between the elements inside the joint. After having tested several approaches, we proposed a new method for collision detection which measures in constant time the signed distance to the closest point for each point of two meshes subject to collide. We also proposed a method for collision response which acts directly on the surfaces geometry, in a way that the physical behavior relies on the propagation of reaction forces produced inside the tissue. Finally, we proposed a 3D model of a joint combining the three elements: anatomical skeleton motion, biomechanical soft tissues deformation, and contact management. On the top of that we built a virtual hip joint and implemented a set of medical applications prototypes. Such applications allow for assessment of stress distribution on the articular surfaces, range of motion estimation based on ligament constraint, ligament elasticity estimation from clinically measured range of motion, and pre- and post-operative evaluation of stress distribution. Although our model provides physicians with a number of useful variables for diagnosis and surgery planning, it should be improved for effective clinical use. Validation has been done partially. However, a global clinical validation is necessary. Patient specific data are still difficult to obtain, especially individualized mechanical properties of tissues. The characterization of material properties in our soft tissues model can also be improved by including control over the shear modulus

Participatory budgeting in COVID-19 times: a perspective from local public administration

The COVID-19 pandemic has changed the daily lives of populations around the world, affected household economies, forced national and subnational governments to manage declining revenues, and transformed patterns of behavior, practices, and processes. In this context of uncertainty, the barriers imposed by the pandemic have somehow affected the implementation of Participatory Budgeting (PB) in several countries. Brazil was a pioneer in the elaboration and adoption of the mechanism in its municipalities, and Portugal is currently the country with the highest rates of PB implementation worldwide. The goal of the paper is to explore the barriers imposed by the global COVID-19 pandemic on PB, considering the perspective of Brazilian and Portuguese Local Public Administration. The research applied an online survey using a Likert-type scale to assess the perception of municipalities about the barriers imposed by COVID-19 pandemic on PB. Public administration officials responsible for carrying out PB, in both the municipalities of the state of Paraná (Brazil) and the municipalities of Portugal, indicated that the crisis caused by COVID-19 pandemic had a negative impact on the carrying out of the processes. There is a sign that the pandemic imposed the alteration of PB processes. As for the possible restrictive consequences of the crisis on the implementation of the mechanism in the future, they are apparently not entirely clear, according to the municipalities analyzed in the two countries. The perception of public administration officials from Portuguese municipalities and cities in the state of Paraná (Brazil) about the obstacles imposed on PB by COVID-19 pandemic can contribute to the ongoing debate about the barriers caused by the crisis.info:eu-repo/semantics/publishedVersio

Participatory budgeting in covid-19 times: a perspective from Paraná and portuguese municipalities

Purpose:  The aim of this article is to explore the barriers imposed by the COVID-19 pandemic to Participatory Budgeting (PB), considering the perspective of Brazilian and Portuguese Local Public Administration. Theoretical framework:  Recent literature points out that the barriers imposed on PB processes arising from the crisis of the COVID-19 pandemic are justified by many leaders due to social distancing measures and the expansion of financial constraints. Design/methodology/approach:  An online questionnaire was applied using a Likert-type scale to assess the perception of public officials, in Paraná and Portugal, about the barriers imposed by the COVID-19 pandemic to PB. Through a quantitative approach, data were presented and analyzed using descriptive statistics and the Chi-square test of adherence. Findings:  The survey contributors from the Portuguese municipalities indicated that the crisis caused by the COVID-19 pandemic had a negative impact on the conduct of PB processes. The possible restrictive consequences caused by the COVID-19 pandemic on the realization of PB in the future are not clear, according to the responses obtained in the two contexts analyzed. Research, Practical & Social implications:  Future studies may include the perspective of the participants in the process and the possible reduction in the amounts available for the execution of the PB due to the pandemic of COVID-19. Originality/value:  COVID-19 alone cannot bring citizens to the periphery of public policy decisions. Difficulties prior to the pandemic, such as the absence of an online platform contributed to limiting the participatory space.Propósito: El objetivo de este artículo es explorar las barreras impuestas por la pandemia del COVID-19 a los Presupuestos Participativos (PP), considerando la perspectiva de la Administración Pública Local brasileña y portuguesa. Metodología: Se aplicó un cuestionario en línea utilizando una escala tipo Likert para evaluar la percepción de los funcionarios públicos, en Paraná y Portugal, sobre las barreras impuestas por la pandemia de COVID-19 en la PB. Mediante un enfoque cuantitativo, los datos se presentaron y analizaron utilizando estadísticas descriptivas y la prueba de Chi-cuadrado de adhesión. Conclusiones: Los encuestados de los municipios portugueses indicaron que la crisis provocada por la pandemia de COVID-19 tuvo un impacto negativo en la realización de los procesos del PP. Las posibles consecuencias restrictivas causadas por la pandemia de COVID-19 sobre la realización de la PB en el futuro no están claras, según las respuestas obtenidas en los dos contextos analizados. Implicaciones de la Investigación: Los estudios futuros pueden incluir la perspectiva de los participantes en el proceso y la posible reducción de las cantidades disponibles para la ejecución de la PB como resultado de la pandemia de COVID-19.Objetivo: O objetivo deste artigo é explorar as barreiras impostas pela pandemia de COVID-19 ao Orçamento Participativo (OP), considerando a perspectiva da Administração Pública Local Brasileira e Portuguesa. Referencial teórico: A literatura recente aponta que as barreiras impostas aos processos de OP decorrentes da crise da pandemia do COVID-19 são justificadas por muitos dirigentes devido às medidas de distanciamento social e à ampliação das restrições financeiras. Desenho/metodologia/abordagem Um questionário online foi aplicado usando uma escala do tipo Likert para avaliar a percepção dos agentes públicos, no Paraná e em Portugal, sobre as barreiras impostas pela pandemia de COVID-19 ao OP. Por meio de uma abordagem quantitativa, os dados foram apresentados e analisados utilizando a estatística descritiva e o teste Qui-quadrado de aderência. Resultados: Os colaboradores da pesquisa dos municípios portugueses indicaram que a crise causada pela pandemia de COVID-19 teve um impacto negativo sobre a realização dos processos de OP. Não são claras as possíveis consequências restritivas provocadas pela pandemia de COVID-19 na realização do OP no futuro, de acordo com as respostas obtidas nos dois contextos analisados. Pesquisa, implicações práticas e sociais: Estudos futuros podem incluir a perspectiva dos participantes no processo e a possível redução dos valores disponíveis para a execução do OP em função da pandemia de COVID-19. Originalidade/valor: A COVID-19 por si só não pode levar os cidadãos à periferia das decisões de políticas públicas. Dificuldades anteriores à pandemia, como a ausência de uma plataforma online contribuíram para limitar o espaço participativo

Operador de Ruelle-Perron-Frobenius e transformações expansoras

Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Ciências Físicas e Matemáticas. Programa de Pós-Graduação em Matemática e Computação CientíficaSeja T uma aplicação expansora em um espaço métrico compacto X. Demonstramos o teorema de Ruelle para potenciais na classe de Schwarz, que é uma classe um pouco mais geral do que a classicamente analisada (apenas Hölder). A demonstração de alguns itens do teorema de Ruelle fica trivial quando usamos o teorema de Ledrappier, que caracteriza as g-medidas. Para o teorema sobre a existência e unicidade das g-medidas, T além de ser expansora deve ser, também, topologicamente mixing. Por fim, estudamos funções expansoras por partes (também conhecidas como aplicações monotônicas ou monótonas por partes). Além do espectro do operador de Ruelle relacionado com estas funções, apresentamos o estado de equilíbrio para tais funções

A FERRADURA DE MEDIDA POSITIVA

http://dx.doi.org/10.5902/2179460X12131The present paper aims to establish the bases for the construction of the Smale’s Horseshoe with positive measure, originallypresented by Rufus Bowen in an article from 1975. To attain this, we start with the construction of Stephen Smale’s classicalhorseshoe, presented by Smale in 1967. Considering figure D in the shape of a stadium on the plane, which contains one square,Q, we will make one contraction and one expansion of D to obtain a figure which looks like a horseshoe. The operations ofcontracting and expanding define one function, that is, f : D ! D. We define Smale’s horseshoe as set l of points q 2 Q Dwhich belong to Q after future and past interactions of function f . This set L is a Cantor set. Bowen’s horseshoe, i.e., Smale’shorseshoe of positive measure, is a set which duplicates Smale’s horseshoe.O presente artigo visa estabelecer as bases para a construção da ferradura de Smale com medida positiva, originalmente apresentada por Rufus Bowen em um artigo de 1975.Para isso, iniciaremos com a construção da clássica ferradura de Stephen Smale, apresentada por Smale em 1967.Considerando uma figura D em forma de estádio no plano, que contém um quadrado Q, faremos uma contração e expansão de D a fim de obter uma figura em forma de ferradura.As operações de contração e expansão definem uma função f : D → D. Definimos então a ferradura de Smale como o conjunto Λ dos pontos q ∈ Q ⊂ D que permanecem em Q após iterações futuras e passadas da aplicação f . Esse conjunto Λ é um conjunto de Cantor.A ferradura de Bowen, ou seja, a ferradura de Smale de medida positiva, é um conjunto que duplica a ferradura de Smale

Rheological Characterization of Commercial Sweetened Condensed Milk

The present study have analyzed samples of sweetened condensed milk of five brands sold in the Brazilian market regarding their rheological behavior and viscoelasticity. The products presented pseudoplastic fluid behavior, illustrated by the experimental data of shear stress versus strain rate, with adjustments made to fit the Power Law and Casson models. The effect of temperature on apparent viscosity of the products followed the Arrhenius model, with activation energy values ranging from 33.8 to 40.9 kJ mol-1. The products showed loss modulus (G’’) greater than storage modulus (G ‘), indicating a semi-liquid material behavior

Laccase: a green catalyst for the biosynthesis of poly-phenols

Laccases (benzene diol: oxidoreductases, EC 1.10.3.2) are able to catalyze the oxidation of various compounds containing phenolic and aniline structures using dissolved oxygen in water. Laccase structural features and catalytic mechanisms focused on the polymerization of aromatic compounds are reported. A description about the most recent research on the biosynthesis of chemicals and polymers is made. Selected applications of this technology are considered as well as the advantages, shortcomings and future needs related with the use of laccases.This study was supported by Chinese Government Scholarship under China Scholarship Council (No. 201606790036) and Chinese Foundation Key projects of governmental cooperation in international scientific and technological innovation (No. 2016 YFE0115700). The authors would also like to acknowledge Portuguese Foundation for Science and Technology (FCT) for the funding of UID/BIO/04469/2013 unit and COMPETE 2020 (POCI-01–0145-FEDER-006684) and BioTecNorte operation (NORTE-01–0145-FEDER-000004) funded by European Regional Development Fund under the scope of Norte2020 – Programa Operacional Regional do Norte.info:eu-repo/semantics/publishedVersio

A Review of Testbeds on SCADA Systems with Malware Analysis

Supervisory control and data acquisition (SCADA) systems are among the major types of Industrial Control Systems (ICS) and are responsible for monitoring and controlling essential infrastructures such as power generation, water treatment, and transportation. Very common and with high added-value, these systems have malware as one of their main threats, and due to their characteristics, it is practically impossible to test the security of a system without compromising it, requiring simulated test platforms to verify their cyber resilience. This review will discuss the most recent studies on ICS testbeds with a focus on cybersecurity and malware impact analysis