Desenvolvimento de um laboratório de ciências para os primeiros anos de escolaridade

A presente comunicação visa apresentar uma proposta de laboratório de ciências para os primeiros anos de escolaridade. Assim, pretende-se: (i) fundamentar a relevância de infraestruturas, equipamentos e recursos de suporte ao ensino das ciências e apresentar princípios orientadores apontados pela literatura para o desenvolvimento de laboratórios escolares e (ii) descrever o processo de concepção, validação e implementação inerente ao desenvolvimento de um laboratório de ciências numa escola do 1.º Ciclo do Ensino Básico (CEB), tendo por base o marco teórico de suporte ao desenvolvimento do mesmo

The relationship between kindergarten children’s vocal performance and recognition of songs with and without words

The ability to recognize songs has been of interest to researchers over the past decades (Racette & Peretz, 2007; Samson & Zatorre, 1991; Serafine, Davidson, Crowder, & Repp, 1986). Evidence on song perception has shown that melody and words are processed with different degrees of integration and separation (Nakada & Abe, 2009; Saito et al., 2012; Sammler et al., 2010). However, there are few studies investigating song recognition among children (Feierabend, Saunders, Holahan, & Getnick, 1998; Morrongiello & Roes, 1990; Rodrigues & Rodrigues, 2010). Furthermore, how songs are taught both with words and without words, i.e., with a neutral syllable, and how words influence perception of melody and words have not been addressed in depth. Also, results from studies regarding the influence of teaching both types of songs on children’s vocal performances were inconclusive and, in some cases, contradictory. For example, some researchers found that children sing better with words (Levinowitz, 1989; Phillips, 1989). In contrast, other investigations did not support these findings and showed no statistical differences between approaches (Jacobi-Karna, 1996; Lange, 2000; Smale, 1988). Within this context, it is unclear if vocal performance of songs with words and without words is related to the way children perceive melody and words.info:eu-repo/semantics/publishedVersio

Dirac-Hestenes spinor fields in Riemann-Cartan spacetime

In this paper we study Dirac-Hestenes spinor fields (DHSF) on a four-dimensional Riemann-Cartan spacetime (RCST). We prove that these fields must be defined as certain equivalence classes of even sections of the Clifford bundle (over the RCST), thereby being certain particular sections of a new bundle named Spin-Clifford bundle (SCB). The conditions for the existence of the SCB are studied and are shown to be equivalent to the famous Geroch's theorem concerning to the existence of spinor structures in a Lorentzian spacetime. We introduce also the covariant and algebraic Dirac spinor fields and compare these with DHSF, showing that all the three kinds of spinor fields contain the same mathematical and physical information. We clarify also the notion of (Crumeyrolle's) amorphous spinors (Dirac-K\"ahler spinor fields are of this type), showing that they cannot be used to describe fermionic fields. We develop a rigorous theory for the covariant derivatives of Clifford fields (sections of the Clifford bundle (CB)) and of Dirac-Hestenes spinor fields. We show how to generalize the original Dirac-Hestenes equation in Minkowski spacetime for the case of a RCST. Our results are obtained from a variational principle formulated through the multiform derivative approach to Lagrangian field theory in the Clifford bundle.Comment: 45 pages, special macros kapproc.sty and makro822.te

The low dimensional dynamical system approach in General Relativity: an example

In this paper we explore one of the most important features of the Galerkin method, which is to achieve high accuracy with a relatively modest computational effort, in the dynamics of Robinson-Trautman spacetimes.Comment: 7 pages, 5 figure

Rigorous Formulation of Duality in Gravitational Theories

In this paper we evince a rigorous formulation of duality in gravitational theories where an Einstein like equation is valid, by providing the conditions under which the Hodge duals (with respect to the metric tensor g) of T^a and R_b^a may be considered as the torsion and curvature 2-forms associated with a connection D', part of a Riemann-Cartan structure (M,g',D'), in the cases g = g' and g does not equal g', once T^a and R_b^a are the torsion and curvature 2-forms associated with a connection D part of a Riemann-Cartan structure (M,g,D). A new form for the Einstein equation involving the dual of the Riemann tensor of D is also provided, and the result is compared with others appearing in the literature.Comment: 15 page

Estudo fitoquímico de Senna alata por duas metodologias.

Senna alata, mais conhecida como mata-pasto na região Norte do Brasil, é uma planta utilizada pela medicina popular em várias partes do mundo e considerada espécie problemática em pastagens do Estado do Pará. No presente estudo, compararam-se duas metodologias distintas para a determinação das principais classes de constituintes potenciais aleloquímicos das diferentes frações (caules, flores, folhas, raízes, sementes e vagens) de S. alata. O material vegetal foi seco e sofreu extração exaustiva com solvente hidrometanólico, para obtenção dos extratos brutos; uma pequena parte dele foi solubilizada em metanol para obtenção das soluções utilizadas nos testes fitoquímicos. As metodologias utilizadas foram: testes por cromatografia em camada delgada (CCD) para determinação do perfil cromatográfico qualitativo; e ensaios para detecção preliminar dos diferentes constituintes químicos, com base na extração destes com solventes apropriados e na aplicação de testes de coloração. Os resultados em ambos os métodos demonstraram pouca semelhança, sendo o CCD o mais simples, barato, rápido e adequado para análise preliminar de compostos químicos derivados de plantas, embora seja um método qualitativo. Este método foi mais sensível para a detecção de flavonoides, porém, para detecção de alcaloides, o reativo de Bouchardat foi mais sensível do que o de Dragendorff, assim como o hidróxido de amônia 10% foi mais sensível às antraquinonas do que o hidróxido de potássio. O estudo comprovou a alta diversidade de compostos químicos presentes em Senna alata, justificando sua ampla utilização na medicina popular e indicando ainda o potencial alelopático para a sua utilização

Map-aided dead-reckoning using only measurements of speed

This is the author accepted manuscript. The final version is available from the publisher via the DOI in this recordWe present a particle-based framework for estimating the position of a vehicle using map information and measurements of speed. The filter propagates the particles’ position estimates by means of dead-reckoning, and then updates the particle weights using two measurement functions. The first measurement function is based on the assumption that the lateral force on the vehicle does not exceed critical limits derived from physical constraints. The second is based on the assumption that the driver approaches a target speed derived from the speed limits along the upcoming trajectory. Assuming some prior knowledge of the initial position, performance evaluations of the proposed method indicate that end destinations often can be estimated with an accuracy in the order of 100 [m]. These results expose the sensitivity and commercial value of speed data collected in many of today’s insurance telematics programs, where the data is used to adjust premiums and provide driver feedback. We end by discussing the strengths and weaknesses of different methods for anonymization and privacy preservation in telematics programs

Impacto de espécies de inverno no rendimento de grãos de culturas de verão e de trigo no inverno subseqüente.

bitstream/CNPT-2010/40292/1/p-bp19.pd