147 resultados para HSM MFR


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Objectivos: Em doentes com traumatismo crânio-encefálico (TCE), o aumento da duração do pré-internamento (internamento em cuidados agudos hospitalares de outras especialidades, antes da admissão em Medicina Física e de Reabilitação) e do internamento no Serviço de Medicina Física e de Reabilitação pode não justificar a sua inclusão ou manutenção na reabilitação em internamento, podendo esta não ser custo-efectiva comparativamente a modelos em ambulatório. O objectivo principal deste trabalho foi avaliar o impacto da duração do pré-internamento e do internamento em Medicina Física e de Reabilitação nos ganhos de funcionalidade obtidos por doentes com TCE. Material e Métodos: Doentes internados por TCE em Medicina Física e de Reabilitação (MFR) entre 1/1/1996 e 31/12/2010 (pré-amostra n = 79). Critérios de inclusão: TCE; pré-internamento <6 meses; internamento em MFR >7 dias. Critérios de exclusão: défices neurológicos e músculo-esqueléticos antes do TCE; intercorrências que condicionassem o programa de reabilitação. Amostra n = 64. O género, idade e os tempos de pré-internamento e de internamento em MFR são as variáveis independentes. Com base nos registos de entrada e alta em MFR, analisou-se a variação de vários parâmetros funcionais (variáveis dependentes). Aplicaram-se modelos estatísticos lineares generalizados: regressão logística, regressão linear múltipla e regressão ordinal logística, nas variáveis com escalas binária, intervalar ou ordinal, respectivamente. Para testar se houve melhoria após o internamento em MFR, aplicou-se o teste paramétrico t para amostras emparelhadas. Resultados: Género (feminino: 32.81%, masculino: 67.19%); média de idades (34.73±14.64 anos); duração média (pré-internamento: 68.03±36.71 dias, internamento em MFR: 46.55±:29.23 dias). O internamento em MFR conduziu a ganhos estatisticamente significativos (p < 6.54x10-2) em todas as variáveis dependentes. A duração de pré-internamento tem uma influência não linear estatisticamente significativa na duração de internamento em MFR (estimativa DPI: 1.18, estimativa DPI2: -5.92x10-3, p DPI: 9.17x10-3, p DPI2: 1.52x10-2). A redução da duração de pré-internamento está associada a uma evolução mais favorável em 20 variáveis, das quais 10 com influência estatisticamente significativa (p < 0.12). O aumento do tempo de internamento em MFR está significativamente associado a maiores ganhos nas escalas MIF e Barthel (p < 4.31x10-3). Conclusões: A duração de pré-internamento tem uma influência não linear na duração do internamento em MFR e constitui um parâmetro de prognóstico funcional em reabilitação. A sua redução é custo-efectiva na reabilitação do TCE e recomenda-se que seja um factor a considerar na selecção de doentes para a reabilitação em internamento. O programa de reabilitação em internamento gera ganhos significativos de funcionalidade, estando uma duração maior associada a ganhos mais favoráveis.

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The purpose of this study is to evaluate the influence of the cutting parameters of high-speed machining milling on the characteristics of the surface integrity of hardened AISI H13 steel. High-speed machining has been used intensively in the mold and dies industry. The cutting parameters used as input variables were cutting speed (v c), depth of cut (a p), working engagement (a e) and feed per tooth (f z ), while the output variables were three-dimensional (3D) workpiece roughness parameters, surface and cross section microhardness, residual stress and white layer thickness. The subsurface layers were examined by scanning electron and optical microscopy. Cross section hardness was measured with an instrumented microhardness tester. Residual stress was measured by the X-ray diffraction method. From a statistical standpoint (the main effects of the input parameters were evaluated by analysis of variance), working engagement (a e) was the cutting parameter that exerted the strongest effect on most of the 3D roughness parameters. Feed per tooth (f z ) was the most important cutting parameter in cavity formation. Cutting speed (v c) and depth of cut (a p) did not significantly affect the 3D roughness parameters. Cutting speed showed the strongest influence on residual stress, while depth of cut exerted the strongest effect on the formation of white layer and on the increase in surface hardness.

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Freudenthal

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Trabalho Final do Curso de Mestrado Integrado em Medicina, Faculdade de Medicina, Universidade de Lisboa, 2014

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Trabalho Final do Curso de Mestrado Integrado em Medicina, Faculdade de Medicina, Universidade de Lisboa, 2014

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Trabalho Final do Curso de Mestrado Integrado em Medicina, Faculdade de Medicina, Universidade de Lisboa, 2014

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The Highway Safety Manual (HSM) estimates roadway safety performance based on predictive models that were calibrated using national data. Calibration factors are then used to adjust these predictive models to local conditions for local applications. The HSM recommends that local calibration factors be estimated using 30 to 50 randomly selected sites that experienced at least a total of 100 crashes per year. It also recommends that the factors be updated every two to three years, preferably on an annual basis. However, these recommendations are primarily based on expert opinions rather than data-driven research findings. Furthermore, most agencies do not have data for many of the input variables recommended in the HSM. This dissertation is aimed at determining the best way to meet three major data needs affecting the estimation of calibration factors: (1) the required minimum sample sizes for different roadway facilities, (2) the required frequency for calibration factor updates, and (3) the influential variables affecting calibration factors. In this dissertation, statewide segment and intersection data were first collected for most of the HSM recommended calibration variables using a Google Maps application. In addition, eight years (2005-2012) of traffic and crash data were retrieved from existing databases from the Florida Department of Transportation. With these data, the effect of sample size criterion on calibration factor estimates was first studied using a sensitivity analysis. The results showed that the minimum sample sizes not only vary across different roadway facilities, but they are also significantly higher than those recommended in the HSM. In addition, results from paired sample t-tests showed that calibration factors in Florida need to be updated annually. To identify influential variables affecting the calibration factors for roadway segments, the variables were prioritized by combining the results from three different methods: negative binomial regression, random forests, and boosted regression trees. Only a few variables were found to explain most of the variation in the crash data. Traffic volume was consistently found to be the most influential. In addition, roadside object density, major and minor commercial driveway densities, and minor residential driveway density were also identified as influential variables.

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The increasing growth in the use of Hardware Security Modules (HSMs) towards identification and authentication of a security endpoint have raised numerous privacy and security concerns. HSMs have the ability to tie a system or an object, along with its users to the physical world. However, this enables tracking of the user and/or an object associated with the HSM. Current systems do not adequately address the privacy needs and as such are susceptible to various attacks. In this work, we analyse various security and privacy concerns that arise when deploying such hardware security modules and propose a system that allow users to create pseudonyms from a trusted master public-secret key pair. The proposed system is based on the intractability of factoring and finding square roots of a quadratic residue modulo a composite number, where the composite number is a product of two large primes. Along with the standard notion of protecting privacy of an user, the proposed system offers colligation between seemingly independent pseudonyms. This new property when combined with HSMs that store the master secret key is extremely beneficial to a user, as it offers a convenient way to generate a large number of pseudonyms using relatively small storage requirements.

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The mining industry faces concurrent pressures of reducing water use, energy consumption and greenhouse gas (GHG) emissions in coming years. However, the interactions between water and energy use, as well as GHG e missions have largely been neglected in modelling studies to date. In addition, investigations tend to focus on the unit operation scale, with little consideration of whole-of-site or regional scale effects. This paper presents an application of a hierarchical systems model (HSM) developed to represent water, energy and GHG emissions fluxes at scales ranging from the unit operation, to the site level, to the regional level. The model allows for the linkages between water use, energy use and GHG emissions to be examined in a fl exible and intuitive way, so that mine sites can predict energy and emissions impacts of water use reduction schemes and vice versa. This paper examines whether this approach can also be applied to the regional scale with multiple mine sites. The model is used to conduct a case study of several coal mines in the Bowen Basin, Australia, to compare the utility of centralised and decentralised mine water treatment schemes. The case study takes into account geographical factors (such as water pumping distances and elevations), economic factors (such as capital and operating cost curves for desalination treatment plants) and regional factors (such as regionally varying climates and associated variance in mine water volumes and quality). The case study results indicate that treatment of saline mine water incurs a trade-off between water and energy use in all cases. However, significant cost differences between centralised and decentralised schemes can be observed in a simple economic analysis. Further research will examine the possibility for deriving model up-scaling algorithms to reduce computational requirements.

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The mining industry faces three long term strategic risks in relation to its water and energy use: 1) securing enough water and energy to meet increased production; 2) reducing water use, energy consumption and emissions due to social, environmental and economic pressures; and 3) understanding the links between water and energy, so that an improvement in one area does not create an adverse effect in another. This project helps the industry analyse these risks by creating a hierarchical systems model (HSM) that represents the water and energy interactions on a sub-site, site and regional scales; which is coupled with a flexible risk framework. The HSM consists of: components that represent sources of water and energy; activities that use water and energy and off-site destinations of water and produced emissions. It can also represent more complex components on a site, with inbuilt examples including tailings dams and water treatment plants. The HSM also allows multiple sites and other infrastructure to be connected together to explore regional water and energy interactions. By representing water and energy as a single interconnected system the HSM can explore tradeoffs and synergies. For example, on a synthetic case study, which represents a typical site, simulations suggested that while a synergy in terms of water use and energy use could be made when chemical additives were used to enhance dust suppression, there were trade-offs when either thickened tailings or dry processing were used. On a regional scale, the HSM was used to simulate various scenarios, including: mines only withdrawing water when needed; achieving economics-of-scale through use of a single centralised treatment plant rather than smaller decentralised treatment plants; and capturing of fugitive emissions for energy generation. The HSM also includes an integrated risk framework for interpreting model output, so that onsite and off-site impacts of various water and energy management strategies can be compared in a managerial context. The case studies in this report explored company, social and environmental risks for scenarios of regional water scarcity, unregulated saline discharge, and the use of plantation forestry to offset carbon emissions. The HSM was able to represent the non-linear causal relationship at the regional scale, such as the forestry scheme offsetting a small percentage of carbon emissions but causing severe regional water shortages. The HSM software developed in this project will be released as an open source tool to allow industry personnel to easily and inexpensively quantify and explore the links between water use, energy use, and carbon emissions. The tool can be easily adapted to represent specific sites or regions. Case studies conducted in this project highlighted the potential complexity of these links between water, energy, and carbon emissions, as well as the significance of the cumulative effects of these links over time. A deeper understanding of these links is vital for the mining industry in order to progress to more sustainable operations, and the HSM provides an accessible, robust framework for investigating these links.

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This paper develops maximum likelihood (ML) estimation schemes for finite-state semi-Markov chains in white Gaussian noise. We assume that the semi-Markov chain is characterised by transition probabilities of known parametric from with unknown parameters. We reformulate this hidden semi-Markov model (HSM) problem in the scalar case as a two-vector homogeneous hidden Markov model (HMM) problem in which the state consist of the signal augmented by the time to last transition. With this reformulation we apply the expectation Maximumisation (EM ) algorithm to obtain ML estimates of the transition probabilities parameters, Markov state levels and noise variance. To demonstrate our proposed schemes, motivated by neuro-biological applications, we use a damped sinusoidal parameterised function for the transition probabilities.

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Polymorphic cocrystals of urea:4,4'-bipyridine and salicylic acid: 4,4'-bipyridine were obtained by crystallization from different solvents. The urea tape is a rare phenomenon in cocrystals but it is consistent in urea:4,4'-bipyridine polymorphic cocrystals. The polymorph obtained from MeCN has symmetrical N-H...N hydrogen bond distances on either side of the urea tape. However, the other form obtained from MeOH has unsymmetrical N-H...N hydrogen bond lengths. In the polymorphic cocrystals of salicylic acid:4,4'-bipyridine, the basic supramolecular synthon acid-pyridine is the same but the 3D packing is different. Both the polymorphic pairs of cocrystals come under the category of packing polymorphs. All polymorphs were characterized by single-crystal X-ray diffraction (SCXRD), PXRD, DSC, FT-IR and HSM. N-H...N and the acid-pyridine supramolecular synthons were insulated by FT-IR vibrational spectroscopy.

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The current work reports quantitative OH species concentration in the cavity of a trapped vortex combustor (TVC) in the context of mixing and flame stabilization studies using both syngas and methane fuels. Planar laser induced fluorescence (PLIF) measurements of OH radical obtained using a Nd: YAG pumped dye laser are quantified using a flat flame McKenna burner. The momentum flux ratio (MFR), defined as the ratio of the cavity fuel jet momentum to that of the guide vane air stream, is observed to be a key governing parameter. At high MFRs similar to 4.5, the flame front is observed to form at the interface of the fuel jet and the air jet stream. This is substantiated by velocity vector field measurements. For syngas, as the MFR is lowered to similar to 0.3, the fuel-air mixing increases and a flame front is formed at the bottom and downstream edge of the cavity where a stratified charge is present. This trend is observed for different velocities at similar equivalence ratios. In case of methane combustion in the cavity, where the MFRs employed are extremely low at similar to 0.01, a different mechanism is observed. A fuel-rich mixture is now observed at the center of the cavity and this mixture undergoes combustion. On further increase of the cavity equivalence ratio, the rich mixture exceeds the flammability limit and forms a thin reaction zone at the interface with air stream. As a consequence, a shear layer flame at the top of the cavity interface with the mainstream is also observed. The equivalence ratio in the cavity also determines the combustion characteristics in the case of fuel-air mixtures that are formed as a result of the mixing. Overall, flame stabilization mechanisms have been proposed, which account for the wide range of MFRs and premixing in the mainstream as well.

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Marine Fishery Reserves (MFRs) are being adopted, in part, as a strategy to replenish depleted fish stocks and serve as a source for recruits to adjacent fisheries. By necessity, their design must consider the biological parameters of the species under consideration to ensure that the spawning stock is conserved while simultaneously providing propagules for dispersal. We describe how acoustic telemetry can be employed to design effective MFRs by elucidating important life-history parameters of the species under consideration, including home range, and ecological preferences, including habitat utilization. We then designed a reserve based on these parameters using data from two acoustic telemetry studies that examined two closely-linked subpopulations of queen conch (Strombus gigas) at Conch Reef in the Florida Keys. The union of the home ranges of the individual conch (aggregation home range: AgHR) within each subpopulation was used to construct a shape delineating the area within which a conch would be located with a high probability. Together with habitat utilization information acquired during both the spawning and non-spawning seasons, as well as landscape features (i.e., corridors), we designed a 66.5 ha MFR to conserve the conch population. Consideration was also given for further expansion of the population into suitable habitats.

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Ecosystem-based management is one of many indispensable components of objective, holistic management of human impacts on nonhuman systems. By itself, however, ecosystem-based management carries the same risks we face with other forms of current management; holism requires more. Combining single-species and ecosystem approaches represents progress. However, it is now recognized that management also needs to be evosystem-based. In other words, management needs to account for all coevolutionary and evolutionary interactions among all species; otherwise we fall far short of holism. Fully holistic practices are quite distinct from the approaches to the management of fisheries that are applied today. In this paper, we show how macroecological patterns can guide management consistently, objectively, and holistically. We present one particular macroecological pattern with two applications. The first application is a case study of fisheries from the Baltic Sea involving historical data for two species; the second involves a sample of 44 species of primarily marine fish worldwide. In both cases we evaluate historical fishing rates and determine holistic/systemic sustainable single-species fishing rates to illustrate that conventional fisheries management leads to much more extensive and pervasive overfishing than currently realized; harvests are, on average, over twenty-fold too large to be fully sustainable. In general, our approach involves not only the sustainability of fisheries and related resources but also the sustainability of the ecosystems and evosystems in which they occur. Using macroecological patterns accomplishes four important goals: 1) Macroecology becomes one of the interdisciplinary components of management. 2) Sustainability becomes an option for harvests from populations of individual species, species groups, ecosystems, and the entire marine environment. 3) Policies and goals are reality-based, holistic, or fully systemic; they account for ecological as well as evolutionary factors and dynamics (including management itself). 4) Numerous management questions can be addressed.