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Search Results: 1 - 10 of 441650 matches for " F. S. Carvalho "
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A produ??o do fracasso escolar: a trajetória de um clássico
Carvalho, José Sérgio F. de;
Psicologia USP , 2011, DOI: 10.1590/S0103-65642011005000023
Abstract: published for the first time more than two decades ago, a produ??o do fracasso escolar, by maria helena souza patto, continues to be a reference work for researchers in education, and teachers. how can one explain its longevity and fecundity in a field that is so marked by rapid obsolescence of authors, theories and educational perspectives? in this article, we present two complementary hypotheses for this solid trajectory of her work. the first one concerns the elucidative potential of her research that refuses the jargon and the procedures that erase the concreteness of the real in favor of a mathematized language and standardizes concepts; what, then, emerges is a complex picture of everyday life in a singular educational institution. on the other hand, in her researches the peculiarity of everyday life of an institution is not taken apart from the historical, political and social conditions which have marked the conceptions and educational practices in our society.
A teoria na prática é outra? Considera??es sobre as rela??es entre teoria e prática em discursos educacionais
Carvalho, José Sérgio F. de;
Revista Brasileira de Educa??o , 2011, DOI: 10.1590/S1413-24782011000200003
Abstract: discussions concerning the relationship between theory and practice in teachers' preparation courses are a particular topic of a long lasting and wide subject, which may go as far back as the beginning of our philosophical tradition. in this article it is analyzed through the exam of two very influential models of pedagogical discourses: the first one which derives theories of education from the great philosophical systems and jean piaget's constructivist approach to education. the article analyses the attempts of transplanting theories from these two fields to educational practice, stressing the abstract character of its prescriptions and the problems which come up from the fact that they simply ignore the culture of everyday school work and its ethical and political basis.
A teoria na prática é outra? Considera es sobre as rela es entre teoria e prática em discursos educacionais
Revista Brasileira de Educa??o , 2011,
Abstract: La cuestión de las relaciones entre la teoría y la práctica en la formación docente es un caso particular de un problema grande y complejo, cuyos esfuerzos de esclarecimiento se remontan al principio de la tradición filosófica. En este trabajo se enfocan dos tipos de discursos pedagógicos que ejerceran gran influencia en la formación docente en todo el siglo XX: las teorías de la educación pertenecientes a los grandes sistemas filosóficos y el discurso pedagógico constructivista de Jean Piaget. El artículo examina los intentos de adaptar las teorías a los campos de la práctica educativa, resaltando el carácter abstracto de las recetas que hacen caso omiso de las prácticas y los problemas propios de la cultura de trabajo de la escuela y de los principios éticos y políticos que históricamente han estado asociadas con los ideales de la educación.
F.L. Kratz,S. de Carvalho
Boletim Goiano de Geografia , 1990,
Abstract: .
Tunicata, Thaliacea, Pyrosomatidae, Pyrosomella verticillata (Neumann, 1909): First record from the southwest Atlantic Ocean.
Carvalho, P. F.,Bonecker, S. L. C.
Check List , 2008,
$β$-exponential inflation
J. S. Alcaniz,F. C. Carvalho
Physics , 2006, DOI: 10.1209/0295-5075/79/39001
Abstract: An inflationary scenario driven by a slow rolling homogeneous scalar field whose potential $V(\Phi)$ is given by a generalized exponential function is discussed. Within the {\sl slow-roll} approximation we investigate some of the main predictions of the model and compare them with current data from Cosmic Microwave Background and Large-Scale Structure observations. In particular, we show that this single scalar field model admits a wider range of solutions than do conventional exponential scenarios and predicts acceptable values of the scalar spectral index and of the tensor-to-scalar ratio for the remaining number of {\sl e-folds} lying in the interval $N = 54 \pm 7$ and energy scales of the order of Planck scale. The running of the spectral index is briefly discussed to show that both negative and positive values are predicted by the model here proposed.
Charm and longitudinal structure functions with the Kharzeev-Levin-Nardi model
Carvalho, F.;Dur es, F. O.;Navarra, F. S.;Szpigel, S.
High Energy Physics - Phenomenology , 2008, DOI: 10.1103/PhysRevC.79.035211
Abstract: We use the Kharzeev-Levin-Nardi model of the low $x$ gluon distributions to fit recent HERA data on charm and longitudinal structure functions. Having checked that this model gives a good description of the data, we use it to predict $F^c_2$ and $F_L$ to be measured in a future electron-ion collider. The results interpolate between those obtained with the de Florian-Sassot and Eskola-Paukkunen-Salgado nuclear gluon distributions. The conclusion of this exercise is that the KLN model, simple as it is, may still be used as an auxiliary tool to make estimates both for heavy ion and electron-ion collisions.
Meson Cloud and SU(3) Symmetry Breaking in Parton Distributions
F. Carvalho,F. O. Dur?es,F. S. Navarra,M. Nielsen,F. M. Steffens
Physics , 1999, DOI: 10.1007/s100520000512
Abstract: We apply the Meson Cloud Model to the calculation of nonsinglet parton distributions in the nucleon sea, including the octet and the decuplet cloud baryon contributions. We give special attention to the differences between nonstrange and strange sea quarks, trying to identify possible sources of SU(3) flavor breaking. A analysis in terms of the $\kappa$ parameter is presented, and we find that the existing SU(3) flavor asymmetry in the nucleon sea can be quantitatively explained by the meson cloud. We also consider the $\Sigma^+$ baryon, finding similar conclusions.
Decomposi??o de folhada de quatro espécies florestais no Norte de Portugal: Taxa de decomposi??o e evolu??o da composi??o estrutural e do teor em nutrientes
Martins,A.; Azevedo,S.; Raimundo,F.; Carvalho,L.; Madeira,M.;
Revista de Ciências Agrárias , 2009,
Abstract: decomposition of senescent leaves of castanea sativa (cs), and needles of pinus pinaster (pp), pinus nigra (pn) and pseudotsuga menziesii (pm) was studied during 3.1 to 3.5 years through weight loss and nutrient concentration evolution, using the litter bag technique, whereas the variation of chemical structural compounds was followed during 391 to 518 days. the highest contents of n were measured in pm and cs (respectively 14.5 and 12.1 g kg-1), which showed lower c/n ratio (39.0, 46.8) than pn and pp (122.2 and 147.7, respectively). highest contents of ca (9.1 g kg-1) and of alcohol and water soluble compounds (384 against 95 to 160 g kg-1 to other species) were measured in pm needles, which also showed the lowest contents of holocelulose (253 g kg-1 against about 500 g kg-1 in the other species). the lignin klason/n ratio decreased according to pp>pn>pm>cs, (71.2, 58.3, 20.5 and 20.3 respectively), and the holocelulose/lignin ratio ranged from 0.9 (pm) to 1.9-2.1 in the other species. annual decay rates, according to the negative exponential model, were ordered according to cs>pn>pm>pp (respectively -0.35, -0.27, -0.19 and -0.16), but with higher values during the first year for cs (-0.60) and pm (0.31). soluble compounds and hemicelulose strongly decreased during the decomposition period, while lignin and cellulose amounts showed a low variability, mainly in pp and pm needles. nutrient amounts decreased during the decomposition process, but remaining quantities for n (41 to 121 %) and p (33 to 104 %) were higher than those estimated for k, ca and mg (respectively 17 to 65%, 30 to 60 % and 18 to 59%). a strong decreasing of c/n ratio was observed especially for pp and pn, where reached 53.2 and 47.1.
Tsallis scaling in the long-range Ising chain with competitive interactions
Carvalho Neto, E. M.;Andrade, R. F. S.;
Brazilian Journal of Physics , 2009, DOI: 10.1590/S0103-97332009000400012
Abstract: a numerically efficient transfer matrix approach is used to investigate the validity of the tsallis scaling hypothesis in the long-range ising spin chain with competitive interactions. in this model, the interaction between two spins i and j placed r lattice steps apart is ji, j = (-1)ζ(i,j)j0/rα, where ζ(i, j) is either 0 or 1. this procedure has succeeded to show the validity of the scaling hypothesis for the well investigated ferromagnetic version of the model, i.e., ζ(i, j)= 0,?i, j, ?α > 0. results are reported for some models of a set, which is defined by requiring ζ(i, j) to be a periodic sequence of 0's and 1's. as expected from symmetry arguments, we find that the hypothesis is not valid when ζ(i, j)= 1,?i, j and α < 1. however, it is verified, with high degree of numerical accuracy, when α < 1, for sequences in which the occurrence of ζ(i, j)= 0 is more frequent than that of ζ(i, j)= 1.
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