As espirais na obra de Francisco Gomes Teixeira

Mestrado em MatemáticaO objectivo desta dissertação é estudar um tipo de curvas notáveis, as espirais, na obra Tratado das Curvas Especiais Notáveis do ilustre matemático Francisco Gomes Teixeira. De uma forma introdutória, apresentamos uma breve descrição da origem da obra acima mencionada, bem como uma análise comparativa entre as suas duas edições Traité des Courbes e Tratado de las Curvas. No estudo das espirais, apresentamos uma descrição detalhada da abordagem feita por Gomes Teixeira, analisando algumas das suas características, principalmente sob o ponto de vista da geometria diferencial, e incluindo algumas correcções e complementos ao trabalho de Gomes Teixeira. Algumas das figuras inseridas no trabalho para ilustrar a forma das espirais, foram construídas recorrendo ao software MathGV.The aim of this thesis is the study of spirals as a special type as curves in the work Tratado das Curvas Especiais Notáveis of the famous Portuguese mathematician Francisco Gomes Teixeira. The origin of Teixeira’s work is described and a comparative study of the two different editions Traité des Courbes e Tratado de las Curvas completes the introductory part. Besides a detailed description of the treatment by Gomes Teixeira the thesis includes the discussion of almost usual characterizations of spirals as objects of elementary differential geometry, including a number of corrections and complements to the work of Gomes Teixeira. Some figures in the descriptive part of the thesis have been constructed with the software package MathGV

Cálculo das variações fracionário

Doutoramento em Matemática e AplicaçõesO cálculo de ordem não inteira, mais conhecido por cálculo fracionário, consiste numa generalização do cálculo integral e diferencial de ordem inteira. Esta tese é dedicada ao estudo de operadores fracionários com ordem variável e problemas variacionais específicos, envolvendo também operadores de ordem variável. Apresentamos uma nova ferramenta numérica para resolver equações diferenciais envolvendo derivadas de Caputo de ordem fracionária variável. Consideram- -se três operadores fracionários do tipo Caputo, e para cada um deles é apresentada uma aproximação dependendo apenas de derivadas de ordem inteira. São ainda apresentadas estimativas para os erros de cada aproximação. Além disso, consideramos alguns problemas variacionais, sujeitos ou não a uma ou mais restrições, onde o funcional depende da derivada combinada de Caputo de ordem fracionária variável. Em particular, obtemos condições de otimalidade necessárias de Euler–Lagrange e sendo o ponto terminal do integral, bem como o seu correspondente valor, livres, foram ainda obtidas as condições de transversalidade para o problema fracionário.The calculus of non–integer order, usual known as fractional calculus, consists in a generalization of integral and differential integer-order calculus. This thesis is devoted to the study of fractional operators with variable order and specific variational problems involving also variable order operators. We present a new numerical tool to solve differential equations involving Caputo derivatives of fractional variable order. Three Caputo-type fractional operators are considered, and for each one of them, an approximation formula is obtained in terms of standard (integer-order) derivatives only. Estimations for the error of the approximations are also provided. Furthermore, we consider variational problems subject or not to one or more constraints, where the functional depends on a combined Caputo derivative of variable fractional order. In particular, we establish necessary optimality conditions of Euler–Lagrange. As the terminal point in the cost integral, as well the terminal state, are free, thus transversality conditions are obtained

A literacia financeira e as necessidades de formação dos estudantes do ensino superior

A literacia financeira tornou-se uma competência social para viver e prosperar na economia moderna, afetando a estabilidade económica e financeira individual e coletiva. As decisões e riscos financeiros assumidos atualmente pela população jovem são muito mais desafiantes do que os assumidos pelas gerações antecessoras, fenómeno associado ao desenvolvimento e complexificação dos mercados financeiros, assim como ao cada vez mais fácil e precoce acesso a produtos e serviços financeiros. A título exemplificativo, os estudantes enfrentam hoje em dia decisões financeiras imediatas: a maioria já é consumidor de serviços financeiros, como contas bancárias com acesso a serviços de pagamento on-line (Lusardi, 2015). Com efeito, é de capital importância que a população jovem detenha conhecimentos financeiros que a ajude a tomar decisões financeiras complexas e que poderão vir a afetar as suas vidas no médio e longo prazo. Estudos realizados pela OCDE demonstram que a maior parte dos estudantes de países de variados níveis de desenvolvimento económico e financeiro demonstram possuir apenas competências básicas de literacia financeira, tais como diferenciar necessidades de desejos ou efetuar a comparação do valor dos bens baseada no preço por unidade (OECD, 2014). Por outro lado, a crise financeira de 2008 veio demonstrar que decisões financeiras mal informadas e inconsequentes (normalmente associadas à falta de literacia financeira) pode ter implicações dramaticamente negativas a nível individual e global (INFE/OECD 2009; OECD 2009). A literacia financeira é, portanto, verdadeiramente uma competência essencial para o século XXI (Lusardi, 2015). A presente investigação visa analisar o nível de literacia financeira dos estudantes universitários. Nesse âmbito, foi aplicado um inquérito por questionário aos estudantes do 1º ano de diversos cursos, da Escola Superior de Educação e Ciências Sociais do Instituto Politécnico de Leiria, onde se procurou avaliar a compreensão de conceitos e fenómenos financeiros tais como: o impacto da inflação nos rendimentos, avaliação das condições de um empréstimo e de um depósito e conhecimento da diferença entre um cartão de débito e um cartão de crédito. O estudo tem ainda como objetivo sistematizar as necessidades de formação financeira consciencializadas pelos estudantes e confrontar os resultados obtidos relativos à literacia financeira dos estudantes com as necessidades de formação financeira que estes estudantes evidenciam. Os resultados obtidos demonstram que os estudantes universitários não compreendem os conceitos e fenómenos financeiros de forma ampla e profunda e evidenciam consciência dos jovens relativamente às necessidades de formação na área financeira.info:eu-repo/semantics/publishedVersio

Antioxidant capacity of Macaronesian traditional medicinal plants

The use of many traditional medicinal plants is often hampered by the absence of a proper biochemical characterization, essential to identify the bioactive compounds present. The leaves from five species endemic to the Macaronesian islands with recognized ethnobotanical applications were analysed: Apollonias barbujana (Cav.) Bornm., Ocotea foetens (Ainton) Baill, Prunus azorica (Mouill.) Rivas-Mart., Lousã, Fern. Prieto, E. Días, J.C. Costa & C. Aguiar, Rumex maderensis Lowe and Plantago arborescens Poir. subsp. maderensis (Dcne.) A. Hans. et Kunk.. Since oxidative stress is a common feature of most diseases traditionally treated by these plants, it is important to assess their antioxidant capacity and determine the molecules responsible for this capacity. In this study, the antioxidant capacity of these plants against two of the most important reactive species in human body (hydroxyl and peroxyl radicals) was determined. To trace the antioxidant origin total phenol and flavonoid contents as well as the polyphenolic profile and the amount of trace elements were determined. There was a wide variation among the species analysed in what concerns their total leaf phenol and flavonoid contents. From the High Performance Liquid Chromatography (HPLC) electrochemically detected peaks it was possible to attribute to flavonoids the antioxidant capacity detected in A. barbujana, O. foetens, R. maderensis and P. azorica extracts. These potential reactive flavonoids were identified for A. barbujana, R. maderensis and P. azorica. For R. maderensis a high content (7 mg g-1 dry weight) of L-ascorbic acid, an already described antioxidant phytomolecule, was found. A high content in selenomethionine (414.35 μg g-1 dry weight) was obtained for P. arborescens subsp. maderensis extract. This selenocompound is already described as a hydroxyl radical scavenger is reported in this work as also possessing peroxyl radical scavenging capacity. This work is a good illustration of different phytomolecules (flavonoids, organic acids and selenocompounds), presents in leaves of the five traditional medicinal plants endemic to Macaronesia, all exhibiting antioxidant propertiesinfo:eu-repo/semantics/publishedVersio

Oral Route Driven Acute Trypanosoma cruzi Infection Unravels an IL-6 Dependent Hemostatic Derangement

Oral transmission of Trypanosoma cruzi, the etiologic agent of Chagas disease, is presently the most important route of infection in Brazilian Amazon. Other South American countries have also reported outbreaks of acute Chagas disease associated with food consumption. A conspicuous feature of this route of transmission is presenting symptoms such as facial and lower limbs edema, in some cases bleeding manifestations and risk of thromboembolism are evident. Notwithstanding, studies that address this route of infection are largely lacking regarding its pathogenesis and, more specifically, the crosstalk between immune and hemostatic systems. Here, BALB/c mice were orally infected with metacyclic trypomastigotes of T. cruzi Tulahuén strain and used to evaluate the cytokine response, primary and secondary hemostasis during acute T. cruzi infection. When compared with control uninfected animals, orally infected mice presented higher pro-inflammatory cytokine (TNF-α, IFN-γ, and IL-6) serum levels. The highest concentrations were obtained concomitantly to the increase of parasitemia, between 14 and 28 days post-infection (dpi). Blood counts in the oral infected group revealed concomitant leukocytosis and thrombocytopenia, the latter resulting in increased bleeding at 21 dpi. Hematological changes paralleled with prolonged activated partial thromboplastin time, Factor VIII consumption and increased D-dimer levels, suggest that oral T. cruzi infection relies on disseminated intravascular coagulation. Remarkably, blockade of the IL-6 receptor blunted hematological abnormalities, revealing a critical role of IL-6 in the course of oral infection. These results unravel that acute T. cruzi oral infection results in significant alterations in the hemostatic system and indicates the relevance of the crosstalk between inflammation and hemostasis in this parasitic disease

Oral Route Driven Acute Trypanosoma cruzi Infection Unravels an IL-6 Dependent Hemostatic Derangement

Submitted by Sandra Infurna ([email protected]) on 2019-07-04T15:19:44Z No. of bitstreams: 1 WilsonSavino_DinaAntunes_etal_IOC_2019.pdf: 2958086 bytes, checksum: 06fc5810e00b55cc4b92335c1120548b (MD5)Approved for entry into archive by Sandra Infurna ([email protected]) on 2019-07-04T15:30:53Z (GMT) No. of bitstreams: 1 WilsonSavino_DinaAntunes_etal_IOC_2019.pdf: 2958086 bytes, checksum: 06fc5810e00b55cc4b92335c1120548b (MD5)Made available in DSpace on 2019-07-04T15:30:53Z (GMT). No. of bitstreams: 1 WilsonSavino_DinaAntunes_etal_IOC_2019.pdf: 2958086 bytes, checksum: 06fc5810e00b55cc4b92335c1120548b (MD5) Previous issue date: 2019Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Pesquisa sobre o Timo. Rio de Janeiro, RJ. Brasil / Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Instituto Nacional de CIência e Tecnologia em NeuroimunoModulação. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Pesquisa sobre o Timo. Rio de Janeiro, RJ. Brasil / Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Instituto Nacional de CIência e Tecnologia em NeuroimunoModulação. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Pesquisa sobre o Timo. Rio de Janeiro, RJ. Brasil / Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Instituto Nacional de CIência e Tecnologia em NeuroimunoModulação. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Pesquisa sobre o Timo. Rio de Janeiro, RJ. Brasil / Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Instituto Nacional de CIência e Tecnologia em NeuroimunoModulação. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Doenças Parasitárias. Rio de Janeiro, RJ. Brasil.undação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Pesquisa sobre o Timo. Rio de Janeiro, RJ. Brasil / Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Instituto Nacional de CIência e Tecnologia em NeuroimunoModulação. Rio de Janeiro, RJ, Brasil.undação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Pesquisa sobre o Timo. Rio de Janeiro, RJ. Brasil / Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Instituto Nacional de CIência e Tecnologia em NeuroimunoModulação. Rio de Janeiro, RJ, Brasil.Universidade Federal do Rio de Janeiro. Instituto de Bioquímica Médica Leopoldo de Meis. Rio de Janeiro, RJ, Brasil.undação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Pesquisa sobre o Timo. Rio de Janeiro, RJ. Brasil / Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Instituto Nacional de CIência e Tecnologia em NeuroimunoModulação. Rio de Janeiro, RJ, Brasil.Oral transmission of Trypanosoma cruzi, the etiologic agent of Chagas disease, is presently the most important route of infection in Brazilian Amazon. Other South American countries have also reported outbreaks of acute Chagas disease associated with food consumption. A conspicuous feature of this route of transmission is presenting symptoms such as facial and lower limbs edema, in some cases bleeding manifestations and risk of thromboembolism are evident. Notwithstanding, studies that address this route of infection are largely lacking regarding its pathogenesis and, more specifically, the crosstalk between immune and hemostatic systems. Here, BALB/c mice were orally infected with metacyclic trypomastigotes of T. cruzi Tulahuén strain and used to evaluate the cytokine response, primary and secondary hemostasis during acute T. cruzi infection. When compared with control uninfected animals, orally infected mice presented higher pro-inflammatory cytokine (TNF-α, IFN-γ, and IL-6) serum levels. The highest concentrations were obtained concomitantly to the increase of parasitemia, between 14 and 28 days post-infection (dpi). Blood counts in the oral infected group revealed concomitant leukocytosis and thrombocytopenia, the latter resulting in increased bleeding at 21 dpi. Hematological changes paralleled with prolonged activated partial thromboplastin time, Factor VIII consumption and increased D-dimer levels, suggest that oral T. cruzi infection relies on disseminated intravascular coagulation. Remarkably, blockade of the IL-6 receptor blunted hematological abnormalities, revealing a critical role of IL-6 in the course of oral infection. These results unravel that acute T. cruzi oral infection results in significant alterations in the hemostatic system and indicates the relevance of the crosstalk between inflammation and hemostasis in this parasitic disease

Geoeconomic variations in epidemiology, ventilation management, and outcomes in invasively ventilated intensive care unit patients without acute respiratory distress syndrome: a pooled analysis of four observational studies

Background: Geoeconomic variations in epidemiology, the practice of ventilation, and outcome in invasively ventilated intensive care unit (ICU) patients without acute respiratory distress syndrome (ARDS) remain unexplored. In this analysis we aim to address these gaps using individual patient data of four large observational studies. Methods: In this pooled analysis we harmonised individual patient data from the ERICC, LUNG SAFE, PRoVENT, and PRoVENT-iMiC prospective observational studies, which were conducted from June, 2011, to December, 2018, in 534 ICUs in 54 countries. We used the 2016 World Bank classification to define two geoeconomic regions: middle-income countries (MICs) and high-income countries (HICs). ARDS was defined according to the Berlin criteria. Descriptive statistics were used to compare patients in MICs versus HICs. The primary outcome was the use of low tidal volume ventilation (LTVV) for the first 3 days of mechanical ventilation. Secondary outcomes were key ventilation parameters (tidal volume size, positive end-expiratory pressure, fraction of inspired oxygen, peak pressure, plateau pressure, driving pressure, and respiratory rate), patient characteristics, the risk for and actual development of acute respiratory distress syndrome after the first day of ventilation, duration of ventilation, ICU length of stay, and ICU mortality. Findings: Of the 7608 patients included in the original studies, this analysis included 3852 patients without ARDS, of whom 2345 were from MICs and 1507 were from HICs. Patients in MICs were younger, shorter and with a slightly lower body-mass index, more often had diabetes and active cancer, but less often chronic obstructive pulmonary disease and heart failure than patients from HICs. Sequential organ failure assessment scores were similar in MICs and HICs. Use of LTVV in MICs and HICs was comparable (42·4% vs 44·2%; absolute difference -1·69 [-9·58 to 6·11] p=0·67; data available in 3174 [82%] of 3852 patients). The median applied positive end expiratory pressure was lower in MICs than in HICs (5 [IQR 5-8] vs 6 [5-8] cm H2O; p=0·0011). ICU mortality was higher in MICs than in HICs (30·5% vs 19·9%; p=0·0004; adjusted effect 16·41% [95% CI 9·52-23·52]; p<0·0001) and was inversely associated with gross domestic product (adjusted odds ratio for a US$10 000 increase per capita 0·80 [95% CI 0·75-0·86]; p<0·0001). Interpretation: Despite similar disease severity and ventilation management, ICU mortality in patients without ARDS is higher in MICs than in HICs, with a strong association with country-level economic status

Evaluation of a quality improvement intervention to reduce anastomotic leak following right colectomy (EAGLE): pragmatic, batched stepped-wedge, cluster-randomized trial in 64 countries

Background Anastomotic leak affects 8 per cent of patients after right colectomy with a 10-fold increased risk of postoperative death. The EAGLE study aimed to develop and test whether an international, standardized quality improvement intervention could reduce anastomotic leaks. Methods The internationally intended protocol, iteratively co-developed by a multistage Delphi process, comprised an online educational module introducing risk stratification, an intraoperative checklist, and harmonized surgical techniques. Clusters (hospital teams) were randomized to one of three arms with varied sequences of intervention/data collection by a derived stepped-wedge batch design (at least 18 hospital teams per batch). Patients were blinded to the study allocation. Low- and middle-income country enrolment was encouraged. The primary outcome (assessed by intention to treat) was anastomotic leak rate, and subgroup analyses by module completion (at least 80 per cent of surgeons, high engagement; less than 50 per cent, low engagement) were preplanned. Results A total 355 hospital teams registered, with 332 from 64 countries (39.2 per cent low and middle income) included in the final analysis. The online modules were completed by half of the surgeons (2143 of 4411). The primary analysis included 3039 of the 3268 patients recruited (206 patients had no anastomosis and 23 were lost to follow-up), with anastomotic leaks arising before and after the intervention in 10.1 and 9.6 per cent respectively (adjusted OR 0.87, 95 per cent c.i. 0.59 to 1.30; P = 0.498). The proportion of surgeons completing the educational modules was an influence: the leak rate decreased from 12.2 per cent (61 of 500) before intervention to 5.1 per cent (24 of 473) after intervention in high-engagement centres (adjusted OR 0.36, 0.20 to 0.64; P < 0.001), but this was not observed in low-engagement hospitals (8.3 per cent (59 of 714) and 13.8 per cent (61 of 443) respectively; adjusted OR 2.09, 1.31 to 3.31). Conclusion Completion of globally available digital training by engaged teams can alter anastomotic leak rates. Registration number: NCT04270721 (http://www.clinicaltrials.gov)