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A b s t r a c t Objective: Parkinson's disease is a common neurodegenerative disorder characterized by motor disabilities and increasing dependence on others for daily life activities with consequent impact on patients' and caregivers' quality of life. Method: A crosssectional study was performed in which quality of life was assessed by the WHOQOL-BREF questionnaire in 21 patients with Parkinson's disease and their respective caregivers. Results: Significant differences between patients and caregivers were found in physical (p < 0.001) and psychological (p = 0.002) domains. In the Parkinson's disease group there was a significant inverse correlation between the psychological domain and duration of disease (p = 0.01), as well as between social domain and severity of disease (p = 0.001). There was a positive correlation between physical domain scores and number of people living in the same house (p = 0.02). The only significant finding in the group of caregivers was an inverse correlation between the social domain and the patients´ age (p = 0.04). Conclusion: Duration, severity of the disease and the number of people living in the same house were the most important predictors of quality of life of Parkinson's disease patients. The age of the patients was the only significant predictor found in the caregivers' quality of life. In order to complement our findings, further short-form questionnaires should be validated for Brazilian samples of Parkinson's disease.Keywords: Quality of life; Parkinson disease; Caregivers; Evaluation studies; Validity Resumo Objetivo: A doença de Parkinson é uma enfermidade neurodegenerativa comum caracterizada por disfunção motora e níveis crescentes de dependência para atividades da vida diária, com conseqüente impacto sobre a qualidade de vida dos pacientes e seus cuidadores. Método: Foi realizado um estudo transversal avaliando qualidade de vida por meio do questionário WHOQOL-BREF em 21 pacientes com doença de Parkinson e seus respectivos cuidadores. Resultados: Diferenças significativas entre pacientes e cuidadores foram encontradas nos domínios físico (p < 0,001) e psicológico (p = 0,002) do questionário WHOQOL-BREF. No grupo dos pacientes, houve uma significativa correlação inversa entre o domínio psicológico e duração da doença (p = 0,01), assim como entre domínio social e gravidade da doença (p = 0,001). Houve uma correlação positiva entre domínio físico e número de pessoas vivendo na mesma casa (p = 0,02). O único achado significativo no grupo dos cuidadores foi uma correlação inversa entre o domínio social e a idade do paciente (p = 0,04). Conclusão: Duração, gravidade e número de pessoas vivendo na mesma casa foram os fatores preditores mais importantes sobre a qualidade de vida dos pacientes com doença de Parkinson. A idade dos pacientes foi o único fator preditor encontrado sobre a qualidade de vida dos cuidadores. Outros questionários de aplicação curta devem ser validados para amostras brasileiras de pacientes com doença de Parkinson no sentido de complementar nossos ach...

Purpose -The purpose of this paper is to further develop the truss-like discrete element method (DEM) in order to make it suitable to deal with damage and fracture problems. Design/methodology/approach -Finite and boundary elements are the best developed methods in the field of numerical fracture and damage mechanics. However, these methods are based on a continuum approach, and thus, the modelling of crack nucleation and propagation could be sometimes a cumbersome task. Besides, discrete methods possess the natural ability to introduce discontinuities in a very direct and intuitive way by simply breaking the link between their discrete components. Within this context, the present work extends the capabilities of a truss-like DEM via the introduction of three novel features: a tri-linear elasto-plastic constitutive law; a methodology for crack discretization and the computation of stress intensity factors; and a methodology for the computation of the stress field components from the unixial discrete-element results. Findings -Obtained results show the suitability and the performance of the proposed methodologies to solve static and dynamic crack problems (including crack propagation) in brittle and elasto-plastic materials. Computed results are in good agreement with experimental and numerical results reported in the bibliography. Research limitations/implications -This paper demonstrates the versatility of the truss-like DEM to deal with damage mechanics problems. The approach used in this work can be extended to the implementation of time-dependent damage mechanisms. Besides, the capabilities of the discrete approach could be exploited by coupling the truss-like DEM to finite and boundary element methods. Coupling strategies would allow using the DEM to model the regions of the problem where crack nucleation and propagation occurs, while finite or boundary elements are used to model the undamaged regions. Originality/value -The scope of the truss-like DEM has been extended. New procedures have been introduced to deal with elastoplastic-crack problems and to improve the post processing of the stress results. IntroductionDuring the 1960s an alternative set of computational methods that do not use a set of differential or integral equations to describe the problem were introduced. Depending on the individual element introduced, such as particles, agents or molecules, methods such as molecular dynamics, discrete element method (DEM), discontinuous deformation analysis, and similar were invented. In the process, computational mechanics of discontinua emerged, and its is now an integral part of cutting edge research in nanotechnology and industrial processes spanning over diverse fields as mining, milling, pharmaceuticals, powders, ceramics, composites, blasting, construction, etc. (Munjiza, 2009).The numerical simulation of fracture and damage problems is always an active research topic. Finite and boundary element methods (BEMs) are the best developed methods in this field (Anderson, 2005;Aliabadi and Rooke, 1991...