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Search Results: 1 - 10 of 603186 matches for " L. A. Amarante Ribeiro "
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A Conjecture about a "vision" model for blind men
L. A. Amarante Ribeiro
Physics , 2001,
Abstract: In this work we present a "vision" model for blind people, preferentially for those ones of birth origin. The model should be implemented using the available computational resources at the moment. The model uses a simulation of an optical image by an appropriate sonorous "image" according to certain rules.
A Conjecture about the Density of Prime Numbers
L. A. Amarante Ribeiro
Mathematics , 2008,
Abstract: We present in this work a heuristic expression for the density of prime numbers. Our expression leads to results which possesses approximately the same precision of the Riemann's function in the domain that goes from 2 to 1010 at least. Instead of using a constant as was done by Legendre and others in the formula of Gauss, we try to adjust the data through a function. This function has the remarkable property: its points of discontinuity are the prime numbers.
Effect of Thermal Fluctuations in the Resonance Fluorescence of a Three-Level System
H. Couto,L. A. Amarante Ribeiro
Physics , 2001,
Abstract: The effect of thermal fluctuations in the resonance fluorescence of a three-level system is studied. The damped three-level system is driven by two strong incident classical fields near resonances frequencies. The simulation of a thermal bath is obtained with a large system of harmonic oscillators that represent the normal modes of the thermal radiation field. The time evolution of the fluorescent light intensities are obtained solving by a iterative method the Heisenberg equations of motion in the integral form. The results show that the time development of the intensity of the fluorescence light is strongly affected by the interaction of the system with the thermal bath.
Um tratamento quantitativo para a classifica??o das línguas Indo-Européias
Ribeiro, Lincoln Almir Amarante;
DELTA: Documenta??o de Estudos em Lingüística Teórica e Aplicada , 2006, DOI: 10.1590/S0102-44502006000200005
Abstract: this work applies the biology cladistic methodology in the analysis of the classification of the indo-european family of languages, through phonologic and morphologic characters of 12 linguistic families. for the phylogenetc analysis of the phonologic and morphologic data we use the method of maximum parsimony. our results point to the existence of the traditional indo-european languages sub-groups certified in the literature and indicate that one can exist an italic-celtic-germanic supergroup.
Estudo da adsor??o/dessor??o de 2,4-D em solos usando técnica cromatográfica
Amarante Junior, Ozelito Possid?nio de;Brito, Natilene Mesquita;Santos, Teresa Cristina Rodrigues dos;Ribeiro, Maria Lúcia;
Eclética Química , 2002, DOI: 10.1590/S0100-46702002000200021
Abstract: this research studied the adsorption and the desorption of the herbicide 2,4-dichlorofenoxyacetic acid (2,4-d) in soil from urbano santos - ma. the region has eucalyptus crops, and they will be used for attainment of cellulose. herbicides, namely 2,4-d, are used for clean the fields before the plantation and in the firsts 12 months. the freundlich isotherm was used as model for this study, and the 2,4-d concentration was determined through high performance liquid chromatography (hplc). this determination was studied by recoveries assays. the results suggest the 2,4-d to show bigger adsorption at organic mater of studied soil that others kinds of the soils. this can results in lower tendency of leaching and degradation, but the herbicide shows high potential of leaching when compared with others pesticides.
Glifosato: propriedades, toxicidade, usos e legisla??o
Amarante Junior, Ozelito Possid?nio de;Santos, Teresa Cristina Rodrigues dos;Brito, Natilene Mesquita;Ribeiro, Maria Lúcia;
Química Nova , 2002, DOI: 10.1590/S0100-40422002000400014
Abstract: this paper supplies a compact revision on the herbicide glyphosate physic-chemistry characteristic mains, including toxicity and valid brazilian legislation for its use.
Breve revis?o de métodos de determina??o de resíduos do herbicida ácido 2,4-diclorofenoxiacético (2,4-D)
Amarante Júnior, Ozelito Possid?nio de;Santos, Teresa Cristina Rodrigues dos;Nunes, Gilvanda Silva;Ribeiro, Maria Lúcia;
Química Nova , 2003, DOI: 10.1590/S0100-40422003000200015
Abstract: this paper supplies a revision about the main techniques of extraction, clean-up and pre-concentration of the herbicide 2,4-dichlorophenoxyacetic acid (2,4-d) in water and soil samples, as well as chromatographic methods and immune assays for its identification and quantification.
Métodos de extra??o e determina??o do herbicida glifosato: breve revis?o
Amarante Júnior, Ozelito Possid?nio de;Santos, Teresa Cristina Rodrigues dos;Brito, Natilene Mesquita;Ribeiro, Maria Lúcia;
Química Nova , 2002, DOI: 10.1590/S0100-40422002000300015
Abstract: this paper supplies a compact revision about the main extraction, clean-up and pre-concentration methods of the herbicide glyphosate for water and soil samples, as well as methods for its determination and quantification.
Glifosato: propriedades, toxicidade, usos e legisla o
Amarante Junior Ozelito Possid?nio de,Santos Teresa Cristina Rodrigues dos,Brito Natilene Mesquita,Ribeiro Maria Lúcia
Química Nova , 2002,
Abstract: This paper supplies a compact revision on the herbicide glyphosate physic-chemistry characteristic mains, including toxicity and valid Brazilian legislation for its use.
Métodos de extra o e determina o do herbicida glifosato: breve revis o
Amarante Júnior Ozelito Possid?nio de,Santos Teresa Cristina Rodrigues dos,Brito Natilene Mesquita,Ribeiro Maria Lúcia
Química Nova , 2002,
Abstract: This paper supplies a compact revision about the main extraction, clean-up and pre-concentration methods of the herbicide glyphosate for water and soil samples, as well as methods for its determination and quantification.
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