77 research outputs found
Reliability analysis of a timber truss system subjected to decay
Assessing the safety of existing timber structures is of paramount importance for taking reliable decisions on repair actions and their extent. The results obtained through semi-probabilistic methods are unrealistic, as the partial safety factors present in codes are calibrated considering the uncertainty exhibited by new structures. In order to overcome these limitations, and also to include the e ects of decay in the safety analysis, probabilistic methods, based on Monte-Carlo simulation are applied here to assess the safety of existing timber structures. In particular, the impact of decay on structural safety is analyzed and discussed using a simple structural model, similar to that used for current semi-probabilistic analysis.Fundação para a Ciência e a Tecnologia (FCT
A review of the current treatment methods for posthaemorrhagic hydrocephalus of infants
Posthaemorrhagic hydrocephalus (PHH) is a major problem for premature infants, generally requiring lifelong care. It results from small blood clots inducing scarring within CSF channels impeding CSF circulation. Transforming growth factor – beta is released into CSF and cytokines stimulate deposition of extracellular matrix proteins which potentially obstruct CSF pathways. Prolonged raised pressures and free radical damage incur poor neurodevelopmental outcomes. The most common treatment involves permanent ventricular shunting with all its risks and consequences
A many-state Markov model for the estimation and prediction of computer software performance parameters
Alcohol and traumatic brain injury: the understated vector of a silent epidemic
Objective: Few studies have analysed the role of alcohol consumption in traumatic brain injury (TBI), with conflicting reports on its effect on outcome. Our aim was to investigate the incidence of alcohol intoxication in our TBI population and its relationship to the severity of injury, intracranial pathology and outcome.Methods: From the TBI database, demographic, injury and clinical details (including alcohol intoxication) were prospectively recorded for 362 patients aged >16 years and admitted to Neurosurgical ITU between September 2005 and September 2008. Data, including mortality and dichotomized GOS (favourable = 4–5; unfavourable = 1–3) at discharge, 6 and 12 months, were analysed using ?2, t-test and ANOVA after normalisation where appropriate.Results: Intoxication was present in 36% of patients who were slightly younger (mean 37.6 vs. 40.1 years) and predominantly males (83%vs. 76%) when compared with non-intoxicated. There was no significant difference between these groups in GCS (median 8 vs. 10), length of stay and outcome. At 6 months, 67% had a favourable outcome (71% at 12 months) and mortality was 8.4%. There was a strong association between alcohol and mechanism of injury (p = 0.02), with assaults being significantly more common in this subgroup.Conclusions: To our knowledge, this is the largest single-centre study on alcohol consumption and TBI. Despite no apparent effect on outcome, intoxication plays a role in over a third of the admissions. Given the disease burden of TBI, this further highlights public health concerns about alcohol in the UK. The focus should perhaps be on the rise in consumption in young people, a group for which TBI remains the largest cause of death and disability.<br/
Preliminary reliability design of a solar-powered high-altitude very long endurance unmanned air vehicle
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