Formulaçao de um elemento finito de cabo incorporando o efeito do atrito (Elemento de cabos escorregando)

O trabalho apresenta a formulacáo geometricamente exata e a implementaçao computacional de um elemento finito de cabo que permite o escorregamento em presenca de atrito. O novo elemento fornece procedimentos naturais para simular o processo de montagem e a resposta aos carregamentos de estruturas de cabos em geral, além de ter campos promissores de aplicaçáo no modelamento de estruturas de concreto protendido e no estudo de oscilaçoes auto-excitáveis. Resultados de exemplos elementares sáo discutidos.Peer Reviewe

Formulaçao de um elemento finito de cabo incorporando o efeito do atrito (Elemento de cabos escorregando)

O trabalho apresenta a formulacáo geometricamente exata e a implementaçao computacional de um elemento finito de cabo que permite o escorregamento em presenca de atrito. O novo elemento fornece procedimentos naturais para simular o processo de montagem e a resposta aos carregamentos de estruturas de cabos em geral, além de ter campos promissores de aplicaçáo no modelamento de estruturas de concreto protendido e no estudo de oscilaçoes auto-excitáveis. Resultados de exemplos elementares sáo discutidos.Peer Reviewe

T-cell immunology : the maths of memory

© Copyright Borghans and Ribeiro. This article is distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use and redistribution provided that the original author and source are credited.Mathematical modeling reveals that long-term immunological memory is maintained in a manner that is even more dynamic than previously thought.info:eu-repo/semantics/publishedVersio

Untangling the immune basis of disease susceptibility

© 2020 Copyright Ribeiro and Graca. This article is distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use and redistribution provided that the original author and source are creditedInteractions between immune cell receptors and proteins that determine disease susceptibility shed light on how different arms of the immune system are involved in three viral infections and Crohn's disease.info:eu-repo/semantics/publishedVersio

American political affiliation, 2003–43: a cohort component projection

The recent rise and stability in American party identification has focused interest on the long-term dynamics of party bases. Liberal commentators cite immigration and youth as forces which will produce a natural Democratic advantage in the future while conservative writers highlight the importance of high Republican fertility in securing Republican growth. These concerns foreground the neglect of demography within political science. This paper addresses this omission by conducting the first ever cohort component projection of American partisan populations to 2043 based on survey and census data. A number of scenarios are modeled, but, on current trends, we predict that American partisanship will shift much less than the nation’s ethnic composition because the parties’ age structures are similar. Still, our projections find that the Democrats gain two to three percentage points from the Republicans by 2043, mainly through immigration, though Republican fertility may redress the balance in the very long term

Introduction to modeling viral infections and immunity

Copyright © 2018 John Wiley & Sons, Inc. All rights reserved.Infectious agents, such as HIV, hepatitis B virus (HBV), hepatitis C virus (HCV), malaria, and influenza remain significant public health threats, with ~41 million people chronically infected by HIV, ~331 million infected by HBV, ~148 million infected by HCV, and ~351 million cases of malaria, according to the Global Burden of Disease 2013 study. In addition, threats of new influenza pandemics or emerging viruses, such as Ebola and Zika, have created alarm in the United States and in many parts of the world. Despite intensive research efforts by public and private institutions, there are still no vaccines for HIV, HCV, malaria, Ebola, Zika, and many other pathogens. Even though there has been enormous progress with antiviral therapies for chronic infections, we are still unable to cure HIV and HBV, and life‐long treatment is needed.info:eu-repo/semantics/publishedVersio

Direct area minimization through dynamic relaxation

Minimal surfaces, characterized by the property of a minimal area within a fixed boundary, offer an interesting design option for membrane structures, since they are uniquely defined and provide economy of material and more regular fabric patterns. Analytical solution for the non-linear equation governing area minimization may be rather difficult for complex boundaries, leaving numerical solution as the only general way to tackle with the problem. In this paper we show that the dynamic relaxation method offers an interesting alternative to solve the area minimization problem, first interpreted as a nonlinear equilibrium problem, then replaced by a pseudo-dynamic analysis, where fictitious masses and damping matrices are arbitrarily chosen to control the stability of the time integration process

Implementation of a simple wrinkling model into argyris’ membrane finite element

This paper presents the implementation of a simple wrinkling/slackening model into the classical Argyris membrane element, comparing the solution performance by Newton’s iterations, using either the tangent stiffness matrix (numerically evaluated through a finite-difference approximation), or a secant stiffness matrix (obtained through the modification of the elasticity matrix, according to a projection technique which decompose deformations into elastic and wrinkle components)