359 research outputs found

    Atmospheric scattering - state of the art

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    Atmospheric scattering is the natural phenomenon mainly responsible for the colours we observe in the sky. Over the years, several realistic computer graphics algorithms have been proposed in order to reproduce these colours. This state of the art is motivated by the large amount of scattered information, and by its great potential usage in a wide range of applications like flight simulators, video games and movies. This paper will cover the most important models and will present their evolution over the years. The first part contains a small introduction to the mechanics behind the light scattering phenomena. The second part will cover the earlier models, very much focused in the physical phenomenon. The third section will cover GPU based models, more focused on performance.Fundação para a Ciência e a Tecnologia (FCT

    Abortos por Trypanosoma vivax no Pantanal Mato-Grossense e Bolívia.

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    Existe um elevado número de espécies de tripanosomas descritos na literatura que infectam animais (Hoare, 1972; Clarkson, 1976; Desquesnes, 1997; Dávila, 2002). Porém, entre os tripanosomas que infectam animais de interesse na pecuária podemos citar: Trypanosoma vivax; T. evansi; T. equiperdum e T. theileri. O T. evansi tem ampla distribuição nas Américas, sendo encontrado no Panamá, Venezuela, Colômbia, Brasil, Bolívia, Paraguai, Argentina e Peru. O T. evansi e o T. vivax são um risco potencial para mais de 500 milhões de bovinos e 100 milhões de búfalos (Peregrine, 1994). Várias são as doenças que interferem no processo reprodutivo de animais domésticos. Dentre as enfermidades que provocam aborto e concorrem para a menor produtividade na fase de cria pode-se considerar a infecção pelo Trypanosoma vivax, tanto em bovinos (Seidl et al., 1999), quanto em ovinos (Bawa et al., 2000).bitstream/CPAP/55975/1/DOC75.pdfFormato Eletrônic

    A dynamic approach to teaching LSS at universities

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    Alongside the European Students of Industrial Engineering and Management (ESTIEM) a team of students from the University of Minho, in cooperation with a corporate partner, developed a free and scalable Lean Six Sigma (LSS) Green-Belt level course for Engineering students. Purpose: The authors aim to depict how free access to LSS Green-Belt knowledge before graduation can positively impact both engineering education and the students when in real-life projects. The purpose is not to build on existing literature, but to provide a practical teaching structure. Methodology: The authors chose to follow the hypothetico-deductive method which consists of formulating hypotheses and comparing them with real-life brought up from their personal experiences while teaching the course. Findings: This case study found a positive impact on both the students responsible for facilitating the training sessions, as well as the ones receiving practical and theoretical knowledge. With more than 60 course graduates, this model is generating positive results in growing awareness for LSS methods. Practical implications: This paper describes a practical application of a novel approach to teaching LSS in Universities along the obstacles surpassed to design it, blending it in the course curricula. It aims to foster similar implementations in other institutions. Originality: A teaching system built with students for students is scalable, low-cost, and highly engaging. Its deployment not only shows how it is possible to advance education by blending an existing LSS course structure but also how students can greatly benefit from a deeper LSS knowledge before their graduation.(undefined

    A new continuous distribution on the unit interval applied to modelling the points ratio of football teams

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    We introduce a new flexible distribution to deal with variables on the unit interval based on a transformation of the sinh–arcsinh distribution, which accommodates different degrees of skewness and kurtosis and becomes an interesting alternative to model this type of data. We also include this new distribution into the generalised additive models for location, scale and shape (GAMLSS) framework in order to develop and fit its regression model. For different parameter settings, some simulations are performed to investigate the behaviour of the estimators. The potentiality of the new regression model is illustrated by means of a real dataset related to the points rate of football teams at the end of a championship from the four most important leagues in the world: Barclays Premier League (England), Bundesliga (Germany), Serie A (Italy) and BBVA league (Spain) during three seasons (2011–2012, 2012–2013 and 2013–2014)

    Serial Changes in Plasma Levels of Cytokines in Patients with Coronary Artery Disease

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    Roberto H Heinisch1, Carlos R Zanetti1, Fabiano Comin1, Juliano L Fernandes2, José A Ramires2, Carlos V Serrano Jr21Federal University of Santa Catarina, Florianópolis, Brazil; 2Heart Institute (InCor), University of São Paulo Medical School, São Paulo, BrazilObjectives: Inflammation is known to be a major determinant of the progression of coronary artery disease (CAD). In the present study we have evaluated the plasma levels of cytokines – tumor necrosis factor-α (TNF), interleukin-1α (IL-1), interleukin-6 (IL-6), interferon-γ (IFN), and interleukin-10 (IL-10) – to examine the association between these cytokines and C-reactive protein (CRP) in patients with CAD.Methods: Patients with acute coronary syndromes (ACS; n = 20) were compared with patients with stable angina (SA; n = 20) and with control volunteers (C; n = 20). Blood samples were collected at the time of admission from all patients and 15 and 30 days thereafter.Results: CRP levels (20.8 ± 8.8 mg/L) (mean ± SEM) were higher at baseline in ACS than SA patients (4.1 ± 0.8 mg/L) or the control subjects (5.1 ± 1.8 mg/L) (p < 0.05). At admission, IL-6 was detected in 50% of the ACS patients and 5% of the SA patients or control subjects, while TNF was detected in 35% of the ACS and SA patients but only in 5% of control subjects. Subsequently, IL-6 levels declined and were no longer detectable, while TNF levels increased among ACS patients at all time periods tested when compared with other patients. The presence of IL-1 and IL-10 were not detectable in the blood samples examined, and IFN could only be detected in the ACS group. A significant correlation was observed between IL-6 and CRP levels (r = 0.4; p < 0.01) in all groups. There were no correlations among any of the other cytokines and CRP levels.Conclusions: Our study demonstrates raised levels of TNF, IL6, IFN, and CRP in patients with ACS and a positive correlation between IL6 and CRP but not with the other cytokines. Keywords: cytokines, tumor necrosis factor-α, interleukin-6, C-reactive protein, coronary artery diseas

    Contemporary characteristics and outcomes in chagasic heart failure compared with other nonischemic and ischemic cardiomyopathy

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    Background: Chagas’ disease is an important cause of cardiomyopathy in Latin America. We aimed to compare clinical characteristics and outcomes in patients with heart failure (HF) with reduced ejection fraction caused by Chagas’ disease, with other etiologies, in the era of modern HF therapies. Methods and Results: This study included 2552 Latin American patients randomized in the PARADIGM-HF (Prospective Comparison of ARNI With ACEI to Determine Impact on Global Mortality and Morbidity in Heart Failure) and ATMOSPHERE (Aliskiren Trial to Minimize Outcomes in Patients With Heart Failure) trials. The investigator-reported etiology was categorized as Chagasic, other nonischemic, or ischemic cardiomyopathy. The outcomes of interest included the composite of cardiovascular death or HF hospitalization and its components and death from any cause. Unadjusted and adjusted Cox proportional hazards models were performed to compare outcomes by pathogenesis. There were 195 patients with Chagasic HF with reduced ejection fraction, 1300 with other nonischemic cardiomyopathy, and 1057 with ischemic cardiomyopathy. Compared with other etiologies, Chagasic patients were more often female, younger, and had lower prevalence of hypertension, diabetes mellitus, and renal impairment (but had higher prevalence of stroke and pacemaker implantation) and had worse health-related quality of life. The rates of the composite outcome were 17.2, 12.5, and 11.4 per 100 person-years for Chagasic, other nonischemic, and ischemic patients, respectively—adjusted hazard ratio for Chagasic versus other nonischemic: 1.49 (95% confidence interval, 1.15–1.94; P=0.003) and Chagasic versus ischemic: 1.55 (1.18–2.04; P=0.002). The rates of all-cause mortality were also higher. Conclusions: Despite younger age, less comorbidity, and comprehensive use of conventional HF therapies, patients with Chagasic HF with reduced ejection fraction continue to have worse quality of life and higher hospitalization and mortality rates compared with other etiologies. Clinical Trial Registration: PARADIGM-HF: URL: http://www.clinicaltrials.gov. Unique identifier: NCT01035255; ATMOSPHERE: URL: http://www.clinicaltrials.gov. Unique identifier: NCT00853658

    The regulator LdhR and the d-lactate dehydrogenase LdhA of Burkholderia multivorans play a role in carbon overflow and in planktonic cellular aggregates formation

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    This paper version is the accepted manuscript posted online 21 July 2017. It has peer-review. This publication hasn't any creative commons license associated. The deposited article version contains attached the supplementary materials within the pdf.LysR-type transcriptional regulators (LTTR) are the most commonly found regulators in Burkholderia cepacia complex, comprising opportunistic pathogens causing chronic respiratory infections in cystic fibrosis (CF) patients. Despite LTTRs being global regulators of pathogenicity in several bacteria, few have been characterized in Burkholderia Here, we showed that gene ldhR of B. multivorans encoding a LTTR is co-transcribed with ldhA encoding a d-lactate dehydrogenase, and evaluate their implication in virulence traits like exopolysaccharide (EPS) synthesis and biofilm formation. Comparison of wild-type (WT) and its isogenic ΔldhR mutant grown in medium with 2% d-glucose revealed a negative impact on EPS biosynthesis and on cells' viability in the presence of LdhR. Loss of viability in WT cells was caused by intracellular acidification as consequence of cumulative organic acids secretion including d-lactate, this last one absent from the ΔldhR mutant supernatant. Furthermore, LdhR is implicated in the formation of planktonic cellular aggregates. WT cell aggregates reached 1000 μm after 24 hours in liquid cultures; in contrast to ΔldhR mutant aggregates that never grew more than 60 μm. Overexpression of d-lactate dehydrogenase LdhA in the ΔldhR mutant partially restored formed aggregates size, suggesting a role for fermentation inside aggregates. Similar results were obtained for surface-attached biofilms, with WT cells producing more biofilm. A systematic evaluation of planktonic aggregates in Burkholderia CF clinical isolates showed aggregates in 40 out of 74. As CF patients' lung environment is microaerophilic and bacteria are found as free aggregates/biofilms, LdhR and LdhA might have central roles in adaptation to this environment.IMPORTANCE Cystic fibrosis patients often suffer from chronic respiratory infections caused by several microorganisms. Among them are the Burkholderia cepacia complex bacteria which cause progressive deterioration of lung function and, in some patients, might develop into fatal necrotizing pneumoniae with bacteremia, known as "cepacia syndrome". Burkholderia pathogenesis is multifactorial since they express several virulence factors, form biofilms, and are highly resistant to antimicrobial compounds, making their eradication from the CF patients' airways very difficult. As Burkholderia is commonly found in the CF lungs in the form of cell aggregates and biofilms, the need to investigate the mechanisms of cellular aggregation is obvious. In this study we demonstrate the importance of a d-lactate dehydrogenase and a regulator, in regulating carbon overflow, cellular aggregates and surface-attached biofilm formation. This not only enhances our understanding of Burkholderia pathogenesis, but can also lead to the development of drugs against these proteins to circumvent biofilm formation.Instituto Gulbenkian de Ciência (Gene Expression Unit); Programa Operacional 833 Regional de Lisboa 2020 grant: (LISBOA-01-0145-FEDER-007317); Fundação para a Ciência e a Tecnologia grants: (PTDC/QUI-BIQ/118260/2010, UID/BIO/04565/2013, SFRH/BPD/86475/2012).info:eu-repo/semantics/acceptedVersio

    Caracterização da deleção do gene pgk em uma cepa vacinal geneticamente modificada de Brucella abortus.

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    Neste trabalho objetiva-se expressar o gene pgk de B. abortus para a caracterização da cepa vacinal geneticamente modificada de B. abortus, 2308Δpgk, e utilização da proteína PGK em testes sorológicos
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