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Search Results: 1 - 10 of 13229 matches for " Marcelo Trevisan; "
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A description of the semiotic metaphor in biology teaching: assertions about the animal cell
Marlon Dantas Trevisan,Marcelo Carbone Carneiro
Investiga??es em Ensino de Ciências , 2010,
Abstract: The main objective of this survey is describing signly the metaphor learning resource, with focus on biology education. Our teorical reference is the peircean semiotics, because it means solid heritage to code surveys implicated at science education, it led us to do an explanation about the main lines about that reference, addressed to researchers and lecturers interested in those reasonings. In the description yearned, another objectives appear: demonstrate diferences between metaphor/analogy and pragmatic analogy; to list metaphors, from cell representation analysis, and argue about principals diferences and probable cognitive consequences between the metaphor event in the visual representation and speech sentences. Therefore we analysed the animal cell of a high school first grade studying book – biology – cell biology – used by S o Paulo and another state students. The findings demonstrate the undeniable importance of the metaphor as a learning tool in the biology education, and new findings about that, such as its limits in the concept elaboration, gnosiologic consequences for receptioning, the search needs for propositions– pictures between concept relations – in the science speech construction, and other results.
Inflationary Lambda-Universe with Time Varying Fundamental Constants
Marcelo Samuel Berman,Luis A. Trevisan
Physics , 2002,
Abstract: Barrow, and Barrow and collaborators, have put forward theoretical models with variable fundamental constants including JBD theories. The experimental evidence for an accelerating Universe points out to a deceleration parameter approximately equal to -- 1. On the other hand, there is evidence for a time varying fine structure constant alpha . We have included the above results in a JBD cosmological model modified by J.D. Barrow by including a time varying speed of light, thus, finding an exponential inflationary phase with variables G, alpha and c . This means that the primordial value of alpha was exponentially larger than its present value. Planck`s time may not be then approximately 10 to the power - 43 s ; the same may happen to other Planck`s quantities. We found an exponentially time-decaying Cosmological term.
Possible Cosmological Implications of Time Varying Fine Structure Constant
Marcelo S. Berman,Luis A. Trevisan
Physics , 2001,
Abstract: We make use of Dirac LNH and results for a time varying fine structure constant in order to derive possible laws of variation for speed of light, the number of nucleons in the Universe, energy density and gravitational constant. By comparing with experimental bounds on G variation, we find that the deceleration paramenter of the present Universe is negative. This is coherent with recent Supernovae observations.
On a time varying fine structure constant
Marcelo S. Berman,Luis A. Trevisan
Physics , 2001,
Abstract: By employing Dirac LNH, and a further generalization by Berman (GLNH), we estimate how should vary the total number of nucleons, the energy density, Newton Gravitational constant, the cosmological constant, the magnetic permeability and electric permitivity, of the Universe,in order to account for the experimentally observed time variation of the fine structure constant. As a bonus,we find an acceptable value for the deceleration parameter of the present Universe, compatible with the Supernovae observations.
Static Generalized Brans-Dicke Universe and Gravitational Waves Amplification
Marcelo S. Berman,Luis A. Trevisan
Physics , 2001,
Abstract: We find a static solution for the scale-factor in a Brans-Dicke generalized theory where the scalar field and the coupling constant vary with time. We find also that in the early Universe there may be amplification of gravitational waves.
Amplification of Gravitational Waves During Inflation in Brans-Dicke Theory
Marcelo S. Berman,Luis A. Trevisan
Physics , 2001,
Abstract: We show that Gravitational Waves are exponetially amplified in the inflationary phase in Brans-Dicke theory, so that it would be possible to detect them and in this way verify several features of physical reality.
Inflationary phase in Generalized Brans-Dicke theory
Marcelo S. Berman,Luis A. Trevisan
Physics , 2001, DOI: 10.1007/s10773-009-9965-5
Abstract: We find a solution for exponential inflation in a Brans-Dicke generalized model, where the coupling "constant " is variable. While in General Relativity the equation of state is p is equal to minus rho, here we find p proportional to rho, where the proportionality constant is smaller than -2/3. The negativity of cosmic pressure implies acceleration of the expansion, even with lambda < 0 >.
Estimate on the deceleration parameter in a Universe with variable fine structure constant
Marcelo S. Berman,Luis A. Trevisan
Physics , 2001,
Abstract: We determine a cosmological model that include a positive acceleration of the Universe and a time decreasing fine structure constant. The present day deceleration parameter is estimated by us, according to our model and the available experimental data .
On the Creation of the Universe out of Nothing
Marcelo Samuel Berman,Luis Augusto Trevisan
Physics , 2001, DOI: 10.1142/S0218271810017342
Abstract: We explain how the Universe was created with no expenditure of energy or initial mass.
PARAFAC: uma ferramenta quimiométrica para tratamento de dados multidimensionais. Aplica??es na determina??o direta de fármacos em plasma humano por espectrofluorimetria
Sena, Marcelo M.;Trevisan, Marcello G.;Poppi, Ronei J.;
Química Nova , 2005, DOI: 10.1590/S0100-40422005000500032
Abstract: since the last decade, the combined use of chemometrics and molecular spectroscopic techniques has become a new alternative for direct drug determination, without the need of physical separation. among the new methodologies developed, the application of parafac in the decomposition of spectrofluorimetric data should be highlighted. the first objective of this article is to describe the theoretical basis of parafac. for this purpose, a discussion about the order of chemometric methods used in multivariate calibration and the development of multi-dimensional methods is presented first. the other objective of this article is to divulge for the brazilian chemical community the potential of the combination parafac/spectrofluorimetry for the determination of drugs in complex biological matrices. for this purpose, two applications aiming at determining, respectively, doxorrubicine and salicylate in human plasma are presented.
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