Tissue composition and density impact on the clinical parameters for 125I prostate implants dosimetry

The MCNPX code was used to calculate the TG-43U1 recommended parameters in water and prostate tissue in order to quantify the dosimetric impact in 30 patients treated with (125)I prostate implants when replacing the TG-43U1 formalism parameters calculated in water by a prostate-like medium in the planning system (PS) and to evaluate the uncertainties associated with Monte Carlo (MC) calculations. The prostate density was obtained from the CT of 100 patients with prostate cancer. The deviations between our results for water and the TG-43U1 consensus dataset values were -2.6% for prostate V100, -13.0% for V150, and -5.8% for D90; -2.0% for rectum V100, and -5.1% for D0.1; -5.0% for urethra D10, and -5.1% for D30. The same differences between our water and prostate results were all under 0.3%. Uncertainties estimations were up to 2.9% for the gL(r) function, 13.4% for the F(r,θ) function and 7.0% for Λ, mainly due to seed geometry uncertainties. Uncertainties in extracting the TG-43U1 parameters in the MC simulations as well as in the literature comparison are of the same order of magnitude as the differences between dose distributions computed for water and prostate-like medium. The selection of the parameters for the PS should be done carefully, as it may considerably affect the dose distributions. The seeds internal geometry uncertainties are a major limiting factor in the MC parameters deduction.

Estimativas da prevalência de desnutrição infantil nos municípios brasileiros em 2006

OBJETIVO: Estimar a prevalência da desnutrição infantil para os municípios brasileiros.MÉTODOS: Utilizou-se modelo de regressão logística multinível para estimar a probabilidade individual de desnutrição em 5.507 municípios brasileiros em 2006, em função de fatores preditivos agrupados segundo níveis hierárquicos. A variável resposta foi a desnutrição infantil (crianças de seis a 59 meses com estatura para idade e sexo inferior a -2 escores Z, segundo o padrão da Organização Mundial da Saúde). As variáveis preditivas foram determinantes da desnutrição aferidos de forma semelhante pela Pesquisa Nacional sobre Demografia e Saúde-2006 e pela Amostra do Censo de 2000. No nível 1 (individual): sexo e idade; no nível 2 (domiciliar): variáveis socioeconômicas, água com canalização interna, área urbana ou rural; e no nível 3 (municipal): localização do município e cobertura da Estratégia Saúde da Família em 2006.RESULTADOS: Detectou-se elevação estatisticamente significativa da chance de desnutrição nas crianças do sexo masculino, que moravam em domicílios com duas ou mais pessoas por cômodo, pertencentes aos quintos inferiores do escore socioeconômico, com três ou mais crianças < 5 anos, que não dispunham de água encanada ou localizados na Região Norte. Verificou-se associação dose-resposta negativa entre a cobertura da Estratégia Saúde da Família e a chance de desnutrição (p = 0,007). Cobertura municipal da Estratégia Saúde da Família > 70% mostrou redução de 45% na chance de desnutrição infantil. Estimativas da prevalência de desnutrição infantil mostraram que a maioria dos municípios estudados apresentou risco de desnutrição sob controle, muito baixo ou baixo. Riscos de maior magnitude foram encontrados em 158 dos municípios, na Região Norte.CONCLUSÕES: A desnutrição infantil como problema de saúde pública concentra-se nos municípios da Região Norte do País, onde a cobertura da Estratégia Saúde da Família é mais baixa. Detectou-se efeito de proteção da Estratégia Saúde da Família em relação à desnutrição infantil no País como um todo, independentemente de outros determinantes do problema.

BANMAC: an opportunistic MAC protocol for reliable communications in body area networks

We consider reliable communications in Body Area Networks (BAN), where a set of nodes placed on human body are connected using wireless links. In order to keep the Specific Absorption Rate (SAR) as low as possible for health safety reasons, these networks operate in low transmit power regime, which however, is known to be error prone. It has been observed that the fluctuations of the Received Signal Strength (RSS) at the nodes of a BAN on a moving person show certain regularities and that the magnitude of these fluctuations are significant (5 - 20 dB). In this paper, we present BANMAC, a MAC protocol that monitors and predicts the channel fluctuations and schedules transmissions opportunistically when the RSS is likely to be higher. The MAC protocol is capable of providing differentiated service and resolves co-channel interference in the event of multiple co-located BANs in a vicinity. We report the design and implementation details of BANMAC integrated with the IEEE 802.15.4 protocol stack. We present experimental data which show that the packet loss rate (PLR) of BANMAC is significantly lower as compared to that of the IEEE 802.15.4 MAC. For comparable PLR, the power consumption of BANMAC is also significantly lower than that of the IEEE 802.15.4. For co-located networks, the convergence time to find a conflict-free channel allocation was approximately 1 s for the centralized coordination mechanism and was approximately 4 s for the distributed coordination mechanism.

Smart-HOP: a reliable handoff mechanism for mobile wireless sensor networks

Handoff processes, the events where mobile nodes select the best access point available to transfer data, have been well studied in cellular and WiFi networks. However, wireless sensor networks (WSN) pose a new set of challenges due to their simple low-power radio transceivers and constrained resources. This paper proposes smart-HOP, a handoff mechanism tailored for mobile WSN applications. This work provides two important contributions. First, it demonstrates the intrinsic relationship between handoffs and the transitional region. The evaluation shows that handoffs perform the best when operating in the transitional region, as opposed to operating in the more reliable connected region. Second, the results reveal that a proper fine tuning of the parameters, in the transitional region, can reduce handoff delays by two orders of magnitude, from seconds to tens of milliseconds.

Vulnerability of mediterranean watersheds to climate change

Desertification is a critical issue for Mediterranean drylands. Climate change is expected to aggravate its extension and severity by reinforcing the biophysical driving forces behind desertification processes: hydrology, vegetation cover and soil erosion. The main objective of this thesis is to assess the vulnerability of Mediterranean watersheds to climate change, by estimating impacts on desertification drivers and the watersheds’ resilience to them. To achieve this objective, a modeling framework capable of analyzing the processes linking climate and the main drivers is developed. The framework couples different models adapted to different spatial and temporal scales. A new model for the event scale is developed, the MEFIDIS model, with a focus on the particular processes governing Mediterranean watersheds. Model results are compared with desertification thresholds to estimate resilience. This methodology is applied to two contrasting study areas: the Guadiana and the Tejo, which currently present a semi-arid and humid climate. The main conclusions taken from this work can be summarized as follows: • hydrological processes show a high sensitivity to climate change, leading to a significant decrease in runoff and an increase in temporal variability; • vegetation processes appear to be less sensitive, with negative impacts for agricultural species and forests, and positive impacts for Mediterranean species; • changes to soil erosion processes appear to depend on the balance between changes to surface runoff and vegetation cover, itself governed by relationship between changes to temperature and rainfall; • as the magnitude of changes to climate increases, desertification thresholds are surpassed in a sequential way, starting with the watersheds’ ability to sustain current water demands and followed by the vegetation support capacity; • the most important thresholds appear to be a temperature increase of +3.5 to +4.5 ºC and a rainfall decrease of -10 to -20 %; • rainfall changes beyond this threshold could lead to severe water stress occurring even if current water uses are moderated, with droughts occurring in 1 out of 4 years; • temperature changes beyond this threshold could lead to a decrease in agricultural yield accompanied by an increase in soil erosion for croplands; • combined changes of temperature and rainfall beyond the thresholds could shift both systems towards a more arid state, leading to severe water stresses and significant changes to the support capacity for current agriculture and natural vegetation in both study areas.

Fusão de hospitais em centros hospitalares : impacto no seu desempenho operacional e financeiro

Mestrado em Contabilidade e Análise Financeira

Fatores associados às dificuldades de adultos na mastigação

OBJETIVO : Estimar a prevalência de dificuldade de adultos na mastigação, segundo sexo, e analisar os fatores associados. MÉTODOS : Estudo transversal de base populacional com adultos de 20 a 59 anos de idade (n = 2.016), de Florianópolis, SC, em 2009, por meio de amostragem em dois estágios, setores censitários e domicílios. A dificuldade na mastigação foi investigada por meio de pergunta sobre dificuldade de mastigação devida a problemas com os dentes ou dentadura. Analisaram-se os fatores  demográficos, socioeconômicos, utilização dos serviços de saúde para consulta odontológica e condição bucal autorreferida. Foi realizada regressão logística multivariável, estratificada por sexo. RESULTADOS : A taxa de resposta foi de 85,3% (n = 1.720). A prevalência de dificuldade na mastigação foi de 13,0% (IC95% 10,3;15,8) e 18,0% (IC95% 14,6;21,3) em homens e em mulheres, respectivamente. Mulheres e homens com 50 anos ou mais, aqueles com dez dentes naturais ou menos e os que manifestaram dor dentária tiveram mais chance de apresentar dificuldade na mastigação. O efeito conjunto da perda e da dor na dificuldade na mastigação foi cerca de quatro vezes maior entre as mulheres. CONCLUSÕES : A magnitude das associações entre variáveis socioeconômicas, demográficas e de condição bucal autorreferidas foi diferente para homens e mulheres, em geral maiores para as mulheres, destacando-se a dor dentária. Os resultados sugerem que o impacto das condições bucais varia segundo o sexo.

Análise estática não linear de um edifício em betão armado

Trabalho Final de Mestrado para obtenção do grau de Mestre em Engenharia Civil

Projeto de fundações e estrutura de ampliação de escola no Açores utilizando os eurocódigos estruturais

Trabalho de Projeto para obtenção do grau de Mestre em Engenharia Civil na Área de Especialização de Estruturas

Calculating an upper bound on the finishing time of a group of threads executing on a GPU: a preliminary case study

Graphics processor units (GPUs) today can be used for computations that go beyond graphics and such use can attain a performance that is orders of magnitude greater than a normal processor. The software executing on a graphics processor is composed of a set of (often thousands of) threads which operate on different parts of the data and thereby jointly compute a result which is delivered to another thread executing on the main processor. Hence the response time of a thread executing on the main processor is dependent on the finishing time of the execution of threads executing on the GPU. Therefore, we present a simple method for calculating an upper bound on the finishing time of threads executing on a GPU, in particular NVIDIA Fermi. Developing such a method is nontrivial because threads executing on a GPU share hardware resources at very fine granularity.

Mid-point for open-ended income category and the effect of equivalence scales on the income-health relationship

To estimate the mid-point of an open-ended income category and to assess the impact of two equivalence scales on income-health associations. Data were obtained from the 2010 Brazilian Oral Health Survey ( Pesquisa Nacional de Saúde Bucal – SBBrasil 2010). Income was converted from categorical to two continuous variables ( per capita and equivalized) for each mid-point. The median mid-point was R$ 14,523.50 and the mean, R$ 24,507.10. When per capita income was applied, 53% of the population were below the poverty line, compared with 15% with equivalized income. The magnitude of income-health associations was similar for continuous income, but categorized equivalized income tended to decrease the strength of association.

Current mortars in conservation: an overview

Renders are an important item in historical buildings and the need for their periodical re-application is a basic conservation procedure. In modern times there has been a trend towards the replacement of traditional pure lime mortars by new formulations including Portland cement or hydraulic lime. Apart from those interventions on specific and very important monuments, in which the use oftraditional non-hydraulic mortars can be enforced, in most of the projects involving less than first order magnitude heritage the use of some sort of hydraulic components is becoming the rule rather than the exception. The present paper describes and analyses the results of an experimental study with ten formulations of current mortars - including some that can hardly be considered as adequate conservation procedures - allowing a direct comparison in terms of some of the most relevant characteristics.

Verificação da segurança à ação sísmica da estrutura de um colégio em Ponta Delgada utilizando o Eurocódigo 8 - parte 3

Dissertação para obtenção do grau de Mestre em Engenharia Civil na Área de Especialização em Estruturas

Análise da afectação sócio-económica causada pela Cril/IC17 sobre o bairro de Santa Cruz de Benfica

Dissertação apresentada na Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa para obtenção do grau de Mestre Integrado em Engenharia do Ambiente, perfil Gestão e Sistemas Ambientais

Imagem de tensor de difusão em alzheimer

Dissertação apresentada na Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa para obtenção do Grau de Mestre em Engenharia Biomédica