Federal University of Pernambuco

About: Federal University of Pernambuco is a education organization based out in Recife, Brazil. It is known for research contribution in the topics: Population & Context (language use). The organization has 22973 authors who have published 35124 publications receiving 426579 citations.

A Systematic Literature Review on Teaching and Learning Introductory Programming in Higher Education

Abstract: Contribution: This paper adds to the results of previous systematic literature reviews by addressing a more contemporary context of introductory programming. It proposes a categorization of introductory programming challenges, and highlights key issues for a research roadmap on introductory programming learning and teaching in higher education. Background: Despite the advances in methods and tools for teaching and learning introductory programming, dropout and failure rates are still high. Published surveys and reviews either cover papers only up to 2007, or focus on methods and tools for teaching introductory programming. Research Questions: 1) What previous skills and background knowledge are key for a novice student to learn programming? 2) What difficulties do novice students encounter in learning how to program? 3) What challenges do teachers encounter in teaching introductory programming? Methodology: Following a formal protocol, automatic and manual searches were performed for work from 2010 to 2016. Of 100 papers selected for data extraction, 89 were retained after quality assessment. Findings: The most frequently cited skills necessary for learning programming were related to problem solving and mathematical ability. Problem solving was also cited as a learning challenge, followed by motivation and engagement, and difficulties in learning the syntax of programming languages. The main teaching challenges concern the lack of appropriate methods and tools, as well as scaling and personalized teaching.

Diretrizes para Cessação do Tabagismo

Abstract: Universidade Federal do Rio de Janeiro (UFRJ) Hospital Universitario Clementino Fraga Filho

Interleukin-10 and interleukin-4 inhibit intracellular killing of Leishmania infantum and Leishmania major by human macrophages by decreasing nitric oxide generation

Abstract: The host response to Leishmania infection is regulated by a specific pattern of local cytokine production. We investigated the effect of interleukin (IL)-10 and IL-4 on the leishmanicidal activity of human macrophages (M phi). As with L. major, intracellular killing of L. infantum by human M phi was obtained following ligation of surface CD23 or cell treatment with interferon-gamma (IFN-gamma). This leishmanicidal activity required nitric oxide (NO) generation by activated M phi, and it was partially mimicked by cell treatment with chemical NO donors. Addition of recombinant human IL-10 or IL-4 to CD23 mAb or IFN-gamma decreased L. infantum and L. major killing by infected M phi. IL-10 was more potent than IL-4 in inhibiting the leishmanicidal activity of human M phi. Inhibition of Leishmania killing by IL-4 and IL-10 correlated with decreased NO generation from M phi, and was reversed when exogenous NO was added to cell cultures. Therefore, IL-10 and IL-4 down-regulate leishmanicidal activity of human M phi, in part by inhibiting NO generation by these cells.

Proterozoic history of the Borborema province (NE Brazil): Correlations with neighboring cratons and Pan-African belts and implications for the evolution of western Gondwana

Abstract: [1] Geological and geochronological correlations between Borborema province (NE Brazil) and neighboring cratons and Brasiliano/Pan-African belts indicate that the Amazonian, West African, and Sao Francisco/Congo cratons and the basement of the Araguaia, Borborema, Nigerian, and Cameroon provinces were part of the Atlantica supercontinent This continent was established at the end of the Transamazonian/Eburnean cycle (∼20 Ga) and, apart from ubiquitous taphrogenesis in the 18–17 Ga interval, remained largely unaffected for the following 1 Ga Around 1 Ga an important magmatic event in Borborema province correlates with rifting episodes and anorogenic magmatism in the Sao Francisco, Congo, and Amazonian cratons These events are interpreted as failed attempts to break up Atlantica, which at this time may have been part of the larger Rodinia supercontinent Renewed extensional conditions in Borborema province during the middle and late Neoproterozoic are attributed to far-field stresses transmitted to the interior of Atlantica by outwardly dipping subduction zones that encircled its northern (present day coordinates) portion The rarity of petrotectonic assemblages typical of subduction zone environments indicates that extension did not evolve enough to form large oceans basins and thus that the Borborema province essentially includes reworked intracontinental domains Regional deformation and metamorphism, starting at 650–640 Ma, and shear zone development, beginning at 590–595 Ma, were continuously developed through time and were synchronous throughout most of the Borborema, Araguaia, Cameroon, and Nigerian provinces Postorogenic conditions were reached 540–530 Myr ago, while active deformation was still occurring in other belts that accreted around Atlantica to form western Gondwana

Mechanisms of non-radiative energy transfer involving lanthanide ions revisited

Abstract: In this work, the theoretical background of the Coulomb direct and exchange interactions in non-radiative energy transfer involving lanthanide ions is critically reviewed. Emphasis is given to the shielding effect produced by the filled 5s and 5p sub-shells of the lanthanide ion and the appropriate use of the so-called forced electric dipole intensity parameters of 4f–4f transitions, two aspects that have been often overlooked in the literature. An effective exchange hamiltonian, based on Mulliken-type approximations, and an expression for the resonant or quasi-resonant energy mismatch spectral overlap factor are proposed. Both cases of ion-to-ion and intramolecular energy transfer processes are discussed. Numerical estimates are compared with previous calculations, showing that order of magnitude differences appear. The analysis indicates that the donor–acceptor distance dependence of transfer rates by the exchange mechanism goes beyond the single exponential behavior adopted from Dexter’s approach.