The Didactic Transposition of the Photoelectric Effect in High School Brazilian Physics Textbooks

É notório que o livro didático desempenha um papel fundamental na prática pedagógica da maioria dos professores de Física constituindo importante fonte de referência para professores e estudantes. Ao mesmo tempo representa a memória impressa das demandas e paradigmas de ensino, e procura atender às exigências prescritas na legislação e diretrizes, de uma determinada localidade e período. Atualmente, a inserção de Física Moderna e Contemporânea no currículo do Ensino Médio brasileiro está entre as prioridades, preconizando, entre. outros, o ensino do efeito fotoelétrico, em função da relevância do fenômeno ao corroborar a interpretação corpuscular da natureza da luz, e o consequente laureio de Albert Einstein com o Prêmio Nobel. Estudos realizados apontam que muitos dos livros didáticos apresentam a história do efeito fotoelétrico de maneira superficial ou errônea, e expõem incorretamente a função trabalho e o conceito de fóton (Klassen, 2011). Tendo em vista o exposto, objetivamos analisar como ocorre a apresentação do efeito fotoelétrico especificamente em dez coleções didáticas brasileiras aprovadas pelo Programa Nacional do Livro Didático do Ensino Médio 2012 do governo federal, tendo como aporte teórico as considerações de Yves Chevallard (Brockington e Pietrocola, 2005). Procuramos resposta para a seguinte pergunta: Quais são as transposições ocorridas na apresentação do efeito fotoelétrico (saber sábio) para se tornar o saber a ensinar em materiais escolares? Nossa análise centrou-se no processo de descontextualização, entendido como o processo pelo qual o saber sábio passa para que seja ensinável, sendo necessário que seja arrancado de seu contexto original, ou seja, o seu processo histórico.

Dental caries in children participating in a dentistry for infants program

To assess the impact of the "Dentistry for Infants" early dental care program run by Jacareí County (SP) by comparing the caries of individuals participating and not participating in this program. Methods: In total, 300 children between 0 and 48 months old were assessed in the following two groups: infants not participating in the program (G1, n = 100) and infants participating in the program (G2, n = 200). Each group was further divided according to age in subgroups of 0 to 24 months and 25 to 48 months. All children were clinically assessed for carious lesions using the visual-tactile method. The data were statistically analyzed using a paired Student's t-test, Mann-Whitney test, and c 2 test at a 5% significance level. Results: There was a significant difference in the prevalence (P) and mean index of deciduous teeth (deft) (C) that were decayed, indicated for extraction and filled, and the highest values were observed in G1 (p < 0.0001). The values were as follows: PG1, 73%; PG2, 22%; CG1, 3.45 ± 3.84; and CG2, 0.66 ± 1.57. Conclusion: Participating in the program positively impacted the infants' oral health.

Equação de Schrödinger não linear com coeficientes modulados

Pós-graduação em Física - FEG

On soft limits of large-scale structure correlation functions

We study soft limits of correlation functions for the density and velocity fields in the theory of structure formation. First, we re-derive the (resummed) consistency conditions at unequal times using the eikonal approximation. These are solely based on symmetry arguments and are therefore universal. Then, we explore the existence of equal-time relations in the soft limit which, on the other hand, depend on the interplay between soft and hard modes. We scrutinize two approaches in the literature: the time-flow formalism, and a background method where the soft mode is absorbed into a locally curved cosmology. The latter has been recently used to set up (angular averaged) 'equal-time consistency relations'. We explicitly demonstrate that the time-flow relations and 'equal-time consistency conditions'are only fulfilled at the linear level, and fail at next-to-leading order for an Einstein de-Sitter universe. While applied to the velocities both proposals break down beyond leading order, we find that the 'equal-time consistency conditions'quantitatively approximates the perturbative results for the density contrast. Thus, we generalize the background method to properly incorporate the effect of curvature in the density and velocity fluctuations on short scales, and discuss the reasons behind this discrepancy. We conclude with a few comments on practical implementations and future directions.

Mobile vector soliton in a spin-orbit coupled spin-1 condensate

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Global ballistic acceleration in a bouncing-ball model

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Natural formations at the Earth-Moon triangular point in perturbed restricted problems

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Bell inequalities for K-0(K)over-bar(0) pairs from Phi-resonance decays

We analyze the premises of recent propositions to test local realism via the Bell inequalities using neutral kaons from φ resonance decays as entangled Einstein-Podolsky-Rosen pairs. We pay special attention to the derivation of the Bell inequalities, or related expressions, for unstable and oscillating kaon quasispin states and to the possibility of the actual identification of these states through their associated decay modes. We discuss an indirect method to extract probabilities to find these states by combining experimental information with theoretical input. However, we still find inconsistencies in previous derivations of the Bell inequalities. We show that the identification of the quasispin states via their associated decay mode does not allow the free choice to perform different tests on them, a property which is crucial to establish the validity of any Bell inequality in the context of local realism. In view of this we propose a different kind of Bell inequality in which the free choice or adjustability of the experimental setup is guaranteed. We also show that the proposed inequalities are violated by quantum mechanics. ©1999 The American Physical Society.

Dark energy as a kinematic effect

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Modelagem do aporte de sedimentos aplicada à bacia hidrográfica contribuinte da PCH Costa Rica (MS) e proposta de mitigação do assoreamento

Pós-graduação em Engenharia Mecânica - FEG

Aprendizado de máquina baseado em tensores e suas aplicacções para floresta de caminhos ótimos

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Transplante multivisceral em suínos: modelo de pesquisa e treinamento

Objective: To present a model for research and training in multivisceral transplantation in pigs. Methods: Eight Large White pigs (four donors and four recipients) were operated. The multivisceral transplant with stomach, duodenum, pancreas, liver and intestine was performed similarly to transplantation in humans with a few differences, described below. Anastomoses were performed as follows: end-to-end from the supra-hepatic vena cava of the graft to the recipient juxta diaphragmatic vena cava; end-to-end from the infra-hepatic vena cava of the graft to the inferior (suprarenal) vena cava of the recipient; and endto-side patch of the aorta of the graft to the infrarenal aorta of the recipient plus digestive reconstruction. Results: The performance of the multivisceral transplantion was possible in all four animals. Reperfusions of the multivisceral graft led to a severe ischemia-reperfusion syndrome, despite flushing of the graft. The animals presented with hypotension and the need for high doses of vasoactive drugs, and all of them were sacrificed after discontinuing these drugs. Conclusion: Some alternatives to minimize the ischemia-reperfusion syndrome, such as the use of another vasoactive drug, use of a third pig merely for blood transfusion, presence of an anesthesia team in the operating room, and reduction of the graft, will be the next steps to enable experimental studies.