Modelling rail track deterioration and maintenance: current practices and future needs

As commercialisation and privatisation of railway systems reach the political agendas in a number of countries, including Australia, the separation of infrastructure from operating business dictates that track costs need to be shared on an equitable basis. There is also a world-wide trend towards increased pressures on rail track infrastructure through increases in axle loads and train speeds. Such productivity and customer service driven pressures inevitably lead to reductions in the life of track components and increases in track maintenance costs. This paper provides a state-of-the-art review of track degradation modeling, as well as an overview of track maintenance decision support systems currently in use in North America and Europe. The essential elements of a maintenance optimisation model currently under development are also highlighted

Impact of different aquatic exercise programs on body composition, functional fitness and cognitive function of non-institutionalized elderly adults: a randomized controlled trial

Aquatic physical exercise programs have become progressively more popular among elderly people. Some of the major physical exercise program disadvantages on land are minimized due to the specific properties of the aquatic environment. The purpose of the present randomized controlled study is to verify the effects of different aquatic physical exercise programs on body composition, functional fitness and cognitive function in non-institutionalized elderly people. For this study, 102 elderly individuals were randomly allocated into four different groups: AerG (n = 25, 71.44 ± 4.84 years); IntG (n = 28, 72.64 ± 5.22 years); ComG (n = 29, 71.90 ± 5.67 years) and CG (n = 20, 73.60 ± 5.25 years). Individuals from the groups AerG, IntG and ComG participated in three different aquatic physical exercise programs for a period of 28 weeks. The CG participants kept to their usual routines. All participants were evaluated for body composition, functional fitness and cognitive function at two time moments, i.e., pre- (M1) and post-intervention (M2). Significant differences for body composition were found between M1 and M2 for FM (p < 0.001), LBM (p < 0.001) and WCir (p < 0.01) in the AerG, for BMI (p < 0.05), FM (p < 0.05), LBM (p < 0.001) and LCir-R (p < 0.05) in the IntG, and for WGT (p < 0.01), FM (p < 0.05), LBM (p < 0.01), LCir-R (p < 0.05) and LCir-L (p < 0.01) in the ComG groups. For functional fitness, differences were found between M1 and M2 for 2m-ST (p < 0.000), 30s-CS (p < 0.000), 30s-AC (p < 0.05), HG-T-R (p < 0.000) and HG-T-L (p < 0.000) in the AerG, for 2m-ST (p < 0.05), BS-R (p < 0.05), 30s-CS (p < 0.000), 30s-AC(p < 0.01), HG-T-R (p < 0.000) and HG-T-L (p < 0.000) in the IntG, and for 30s-CS (p < 0.000), HG-T-R (p < 0.000) and HG-T-L (p < 0.000) in the ComG groups. The present study evidenced the beneficial effects of physical exercise in an aquatic environment on body composition, functional fitness and cognitive function in non-institutionalized elderly adults. The ComG water-based exercise program showed more beneficial effects in the improvement of body composition and cognitive function variables, while the IntG and AerG programs were more effective in the improvement of functional fitness.info:eu-repo/semantics/publishedVersio

Inhomogeneous cosmologies with Q-matter and varying Λ\Lambda

Starting from the inhomogeneous shear--free Nariai metric we show, by solving the Einstein--Klein--Gordon field equations, how a self--interacting scalar field plus a material fluid, a variable cosmological term and a heat flux can drive the universe to its currently observed state of homogeneous accelerated expansion. A quintessence scenario where power-law inflation takes place for a string-motivated potential in the late--time dominated field regime is proposed.Comment: 11 pages, Revtex. To be published in Physical Review

Internamento por malária importada em crianças, em dois hospitais da Grande Lisboa

Introdução: Apesar de em Portugal não haver malária endógena, a crescente mobilidade das populações e os laços históricos com África possibilitam a importação de casos para o nosso país. O presente estudo pretende contribuir para melhorar o conhecimento epidemiológico e clínico da malária importada na região de Lisboa Métodos: Realizou-se um estudo descritivo das crianças com malária, internadas em dois hospitais da Grande Lisboa, durante um período de seis anos (1999-2004). Resultados: Foram identificados 134 casos, sendo a mediana das idades de sete anos. A maioria (93,3%) era de origem africana e referia estadia em região endémica (90%). O Plasmodium falciparum foi o agente etiológico mais frequente (73%). A febre foi a manifestação clínica mais frequente, seguida de manifestações gastrointestinais e cefaleias. Ocorreram complicações em 42% dos doentes, sendo a trombocitopenia (19,4%) e a anemia grave (9%) as mais frequentes. A halofantrina e o quinino foram os anti-maláricos mais usados. Conclusões: A malária importada é uma patologia relativamente comum na Grande Lisboa e, dada a inespecificidade do quadro clínico, todas as crianças febris ou doentes com estadia recente num país endémico devem ser rastreadas para esta entidade