Resultados da pesquisa

Catálogo de Publicações - Todos

Filtros
  1. 1

    Assessment of passive drag in swimming by numerical simulation and analytical procedure

    Publicação
    por Barbosa, Tiago M.
    Outros Autores: Ramos, Rui; Silva, António; Marinho, Daniel
    Origem: uBibliorum
    The aim was to compare the passive drag-gliding underwater by a numerical simulation and an analytical procedure. An Olympic swimmer was scanned by computer tomography and modelled gliding at a 0.75-m depth in the streamlined position. Steady-state computer fluid dynamics (CFD) analyses were performed on Fluent. A set of analytical procedures was selected concurrently. Friction drag (Df), pressure drag (Dpr), total passive drag force (Df+pr) and drag coefficient (CD) were computed between 1.3 and 2.5 m · s-1 by both techniques. Df+pr ranged from 45.44 to 144.06 N with CFD, from 46.03 to 167.06 N with the analytical procedure (differences: from 1.28% to 13.77%). CD ranged between 0.698 and 0.622 by CFD, 0.657 and 0.644 by analytical procedures (differences: 0.40-6.30%). Linear regression models showed a very high association for Df+pr plotted in absolute values (R2 = 0.98) and after log-log transformation (R2 = 0.99). The CD also obtained a very high adjustment for both absolute (R2 = 0.97) and log-log plots (R2 = 0.97). The bias for the Df+pr was 8.37 N and 0.076 N after logarithmic transformation. Df represented between 15.97% and 18.82% of the Df+pr by the CFD, 14.66% and 16.21% by the analytical procedures. Therefore, despite the bias, analytical procedures offer a feasible way of gathering insight on one's hydrodynamics characteristics.
    2017 artigo Portugal acesso aberto
  2. 2

    Distribuição espacial e contexto socioeconômico da tuberculose, Rio de Janeiro, Brasil

    Publicação
    por Pereira, Alessandra Gonçalves Lisbôa
    Outros Autores: Medronho, Roberto de Andrade; Escosteguy, Claudia Caminha; Valencia, Luis Iván Ortiz; Magalhães, Mônica de Avelar Figueiredo Mafra
    Origem: Oasisbr
    OBJECTIVE To analyze the spatial distribution of risk for tuberculosis and its socioeconomic determinants in the city of Rio de Janeiro, Brazil.METHODS An ecological study on the association between the mean incidence rate of tuberculosis from 2004 to 2006 and socioeconomic indicators of the Censo Demográfico (Demographic Census) of 2000. The unit of analysis was the home district registered in the Sistema de Informação de Agravos de Notificação (Notifiable Diseases Information System) of Rio de Janeiro, Southeastern Brazil. The rates were standardized by sex and age group, and smoothed by the empirical Bayes method. Spatial autocorrelation was evaluated by Moran’s I. Multiple linear regression models were studied and the appropriateness of incorporating the spatial component in modeling was evaluated.RESULTS We observed a higher risk of the disease in some neighborhoods of the port and north regions, as well as a high incidence in the slums of Rocinha and Vidigal, in the south region, and Cidade de Deus, in the west. The final model identified a positive association for the variables: percentage of permanent private households in which the head of the house earns three to five minimum wages; percentage of individual residents in the neighborhood; and percentage of people living in homes with more than two people per bedroom.CONCLUSIONS The spatial analysis identified areas of risk of tuberculosis incidence in the neighborhoods of the city of Rio de Janeiro and also found spatial dependence for the incidence of tuberculosis and some socioeconomic variables. However, the inclusion of the space component in the final model was not required during the modeling process.
    2015 artigo Brasil
  3. 3

    International Experience of Mechanical Thrombectomy During the COVID-19 Pandemic: Insights from STAR and ENRG

    Publicação
    por Kasab, S
    Outros Autores: Almallouhi, E; Alawieh, A; Levitt, M; Jabbour, P; Sweid, A et al.
    Background: In response to the COVID-19 pandemic, many centers altered stroke triage protocols for the protection of their providers. However, the effect of workflow changes on stroke patients receiving mechanical thrombectomy (MT) has not been systematically studied. Methods: A prospective international study was launched at the initiation of the COVID-19 pandemic. All included centers participated in the Stroke Thrombectomy and Aneurysm Registry (STAR) and Endovascular Neurosurgery Research Group (ENRG). Data was collected during the peak months of the COVID-19 surge at each site. Collected data included patient and disease characteristics. A generalized linear model with logit link function was used to estimate the effect of general anesthesia (GA) on in-hospital mortality and discharge outcome controlling for confounders. Results: 458 patients and 28 centers were included from North America, South America, and Europe. Five centers were in high-COVID burden counties (HCC) in which 9/104 (8.7%) of patients were positive for COVID-19 compared with 4/354 (1.1%) in low-COVID burden counties (LCC) (P<0.001). 241 patients underwent pre-procedure GA. Compared with patients treated awake, GA patients had longer door to reperfusion time (138 vs 100 min, P=<0.001). On multivariate analysis, GA was associated with higher probability of in-hospital mortality (RR 1.871, P=0.029) and lower probability of functional independence at discharge (RR 0.53, P=0.015). Conclusion: We observed a low rate of COVID-19 infection among stroke patients undergoing MT in LCC. Overall, more than half of the patients underwent intubation prior to MT, leading to prolonged door to reperfusion time, higher in-hospital mortality, and lower likelihood of functional independence at discharge.
    2020 artigo Portugal acesso aberto
  4. 4

    The Effect of Long-Chain Polyunsaturated Fatty Acids Intake During Pregnancy on Adiposity of Healthy Full-Term Offspring at Birth

    Publicação
    por Pereira-da-Silva, L
    Outros Autores: Cabo, C; Moreira, AC; Papoila, AL; Virella, D; Neves, R et al.
    OBJECTIVE: The adjusted effect of long-chain polyunsaturated fatty acid (LCPUFA) intake during pregnancy on adiposity at birth of healthy full-term appropriate-for-gestational age neonates was evaluated. STUDY DESIGN: In a cross-sectional convenience sample of 100 mother and infant dyads, LCPUFA intake during pregnancy was assessed by food frequency questionnaire with nutrient intake calculated using Food Processor Plus. Linear regression models for neonatal body composition measurements, assessed by air displacement plethysmography and anthropometry, were adjusted for maternal LCPUFA intakes, energy and macronutrient intakes, prepregnancy body mass index and gestational weight gain. RESULT: Positive associations between maternal docosahexaenoic acid intake and ponderal index in male offspring (β=0.165; 95% confidence interval (CI): 0.031-0.299; P=0.017), and between n-6:n-3 LCPUFA ratio intake and fat mass (β=0.021; 95% CI: 0.002-0.041; P=0.034) and percentage of fat mass (β=0.636; 95% CI: 0.125-1.147; P=0.016) in female offspring were found. CONCLUSION: Using a reliable validated method to assess body composition, adjusted positive associations between maternal docosahexaenoic acid intake and birth size in male offspring and between n-6:n-3 LCPUFA ratio intake and adiposity in female offspring were found, suggesting that maternal LCPUFA intake strongly influences fetal body composition.
    2015 artigo Portugal acesso aberto
  5. 5

    Does Admission NT-ProBNP Increase the Prognostic Accuracy of GRACE Risk Score in the Prediction of Short-Term Mortality After Acute Coronary Syndromes?

    Publicação
    por Timóteo, AT
    Outros Autores: Toste, A; Ramos, R; Miranda, F; Ferreira, ML; Oliveira, JA et al.
    BACKGROUND: NT-proBNP has prognostic implications in heart failure. In acute coronary syndromes (ACS) setting, the prognostic significance of NT-proBNP is being sought. We studied short-term prognostic impact of admission NT-proBNP in patients admitted for ACS and in association with GRACE risk score (GRS). METHODS AND RESULTS: We studied 1035 patients admitted with ACS. Patients were divided in quartiles according to NT-proBNP levels on admission: Q1 <180 pg/ml; Q2 180-691 pg/ml; Q3 696-2664 pg/ml; Q4 2698-35 000 pg/ml. Groups were compared in terms of short-term all-cause mortality. Patients with higher NT-proBNP had worst GRS on admission. They also received less aggressive treatment. In-hospital mortality was 0.8%, 3.0%, 5.8% and 12.8% (P<0.001) and 30-day mortality 1.6%, 4.6%, 6.5% and 16.7% (P<0.001) respectively. In multivariate logistic regression analysis, NT-proBNP is an independent predictor of in-hospital (OR 2.35; 95% CI: 1.12-4.93, P=0.022) and 30-day mortality (OR 2.20; 95% CI: 1.17-4.12, P=0.014). However, NT-proBNP does not add any incremental benefit to GRS for prediction of outcome by ROC curve analysis. CONCLUSIONS: NT-proBNP is an independent predictor of in-hospital and 30-day mortality after ACS, independently of left ventricular function, but does not increase the prognostic accuracy of GRS.
    2009 artigo Portugal acesso aberto
  6. 6

    Sobre a Definição de Outlier no Domínio Específico dos Modelos Lineares e Séries Temporais

    Publicação
    por Jorge, Ana Maria Nabais
    0 que são outliers e o que é o problema outlier? O principal objectivo desta dissertação é fazer o ponto da situação sobre o conceito outlier e como este é tratado no domínio específico dos modelos lineares e das séries temporais, para além de tentar saber como é que os mais modernos pacotes estatísticos tratam o tema. Assim, o nosso trabalho encontra-se dividido em seis capítulos. No primeiro capítulo, são enunciados os objectivos da presente dissertação e as suas motivações. No segundo capítulo, faz-se um apanhado de como o conceito outlier é definido pelos principais autores da especialidade assim como uma breve resenha histórica à evolução do tratamento dado a estas observações, desde Bernoulli até aos dias de hoje. O terceiro capítulo é dedicado à teoria geral de outliers, destacando-se os principais modelos e testes de discordância assim como alguns métodos de acomodação. O quarto capítulo é dedicado à análise do conceito outlier no âmbito dos modelos lineares. São referidos métodos de detecção, assim como alternativas robustas à estimação de mínimos quadrados. São ainda analisados vários pacotes estatísticos. O objectivo do quinto capítulo consiste no estudo de outliers em séries temporais. Serão classificados vários tipos de outliers. Será descrito e exem¬plificado um procedimento iterativo de detecção e estimação dos parâmetros da série proposto por Chang, Tiao e Chen (1988). Finalmente, no sexto capítulo extraem-se algumas conclusões sobre o tema.
    1999 dissertação de mestrado Portugal acesso restrito
  7. 7

    Seed dispersal networks in the Galapagos and the consequences of alien plant invasions

    Publicação
    por Heleno, Ruben
    Outros Autores: Olesen, J. M.; Nogales, M.; Vargas, P.; Traveset, A.
    Alien plants are a growing threat to the Galápagos unique biota. We evaluated the impact of alien plants on eight seed dispersal networks from two islands of the archipelago. Nearly 10 000 intact seeds from 58 species were recovered from the droppings of 18 bird and reptile dispersers. The most dispersed invaders were Lantana camara, Rubus niveus and Psidium guajava, the latter two likely benefiting from an asynchronous fruit production with most native plants, which facilitate their consumption and spread. Lava lizards dispersed the seeds of 27 species, being the most important dispersers, followed by small ground finch, two mockingbirds, the giant tortoise and two insectivorous birds. Most animals dispersed alien seeds, but these formed a relatively small proportion of the interactions. Nevertheless, the integration of aliens was higher in the island that has been invaded for longest, suggesting a time-lag between alien plant introductions and their impacts on seed dispersal networks. Alien plants become more specialized with advancing invasion, favouring more simplified plant and disperser communities. However, only habitat type significantly affected the overall network structure. Alien plants were dispersed via two pathways: dry-fruited plants were preferentially dispersed by finches, while fleshy fruited species were mostly dispersed by other birds and reptiles.
    2012 artigo Portugal acesso aberto
  8. 8

    Age estimation by pulp/tooth ratio in lateral and central incisors by peri-apical X-ray

    Publicação
    por Cameriere, R.
    Outros Autores: Cunha, E.; Wasterlain, S. N.; De Luca, S.; Sassaroli, E.; Pagliara, F. et al.
    Since 2004, several papers on the analysis of the apposition of secondary dentine have been published. The aim of this paper was to study a sample of peri-apical X-ray images of upper and lower incisors, both lateral and medial, to examine the application of pulp/tooth area ratio as an indicator of age. A sample of 116 individuals, 62 men and 54 women, aged between 18 and 74 years, was studied. Data were fitted with age as a linear function of the pulp/tooth ratio of incisors. The total variance explained by the regression equation ranged from 51.3% of age, when lower lateral incisors were used as explanatory variable, to 81.6% when upper lateral incisors were used. The accuracy of the corresponding regression model yielded ME = 8.44 and 5.34 years, respectively. These results show that, although incisors are less reliable than canines or lower premolars, they can be used to estimate age-at-death when the latter are absent.
    2013 artigo Portugal acesso embargado
  9. 9

    Spatial distribution and socioeconomic context of tuberculosis in Rio de Janeiro, Brazil

    Publicação
    por Pereira,Alessandra Gonçalves Lisbôa
    Outros Autores: Medronho,Roberto de Andrade; Escosteguy,Claudia Caminha; Valencia,Luis Iván Ortiz; Magalhães,Mônica de Avelar Figueiredo Mafra
    Origem: Oasisbr
    OBJECTIVE To analyze the spatial distribution of risk for tuberculosis and its socioeconomic determinants in the city of Rio de Janeiro, Brazil.METHODS An ecological study on the association between the mean incidence rate of tuberculosis from 2004 to 2006 and socioeconomic indicators of the Censo Demográfico (Demographic Census) of 2000. The unit of analysis was the home district registered in the Sistema de Informação de Agravos de Notificação (Notifiable Diseases Information System) of Rio de Janeiro, Southeastern Brazil. The rates were standardized by sex and age group, and smoothed by the empirical Bayes method. Spatial autocorrelation was evaluated by Moran’s I. Multiple linear regression models were studied and the appropriateness of incorporating the spatial component in modeling was evaluated.RESULTS We observed a higher risk of the disease in some neighborhoods of the port and north regions, as well as a high incidence in the slums of Rocinha and Vidigal, in the south region, and Cidade de Deus, in the west. The final model identified a positive association for the variables: percentage of permanent private households in which the head of the house earns three to five minimum wages; percentage of individual residents in the neighborhood; and percentage of people living in homes with more than two people per bedroom.CONCLUSIONS The spatial analysis identified areas of risk of tuberculosis incidence in the neighborhoods of the city of Rio de Janeiro and also found spatial dependence for the incidence of tuberculosis and some socioeconomic variables. However, the inclusion of the space component in the final model was not required during the modeling process.
    2015 artigo Brasil acesso aberto
  10. 10

    Mortalidade dos adultos por doenças cardiovasculares e fatores associados nas microrregiões do semiárido brasileiro

    Publicação
    por Silva, Telmo Cristiano Gomes da
    Origem: Oasisbr
    Diseases of the circulatory system (CDs) represent the main group of causes of death in the world and in Brazil, whose main causes of death are ischemic heart disease (IHD) and acute myocardial infarction (AMI). In Brazil, even with CDs mortality decrease, several studies have found social disadvantages in the geographical areas. In the brazilian semiarid there were found higher mortality levels, differentiated from the rest of the country. In the area the problem that exists is remarkable regarding the quality mortality indicators. Without a proper treatment of such data it is difficult to draw tracing scenarios that regard to decisions to be taken by managers. In this context this research sought to understand the relationship of mortality from cardiovascular disease with indicators that express the living conditions of the adult population of the brazilian semiarid. This was an ecological cross-sectional study for 2010, with the unit of analysis the micro-regions that make up the Brazilian semiarid region. Mortality data were obtained from the Mortality Information System (MIS) of the Ministry of Health. The disease classification is defined according to ICD-10, adapted to Brazil by ICD-10-BR and that are available. Population data are sourced from the Brazilian Institute of Geography and Statistics (IBGE). The socioeconomic demographic information was obtained from the Programme for United Nations Development Programme (UNDP). Percentage, mortality rates and the regional mortality rate were calculated to draw the profile of mortality from DCs and the main causes of death of micro-regions of semiarid region. The beta regression was used to examine relationships between death from DCs and socioeconomic and demographic factors for both sexes. Association was found in mortality of men with the survival probability indicators up to 60 years, life expectancy at birth, domicile percentage with electricity and aging rate and the IDHMRenda women, percentage of households with bathrooms and water plumbing fixtures and the probability of survival up to 60 years. It is expected that the understanding of these findings will contribute to the development of preventive actions in a region with few studies on this approach.
    2016 dissertação de mestrado Brasil acesso aberto