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Search Results: 1 - 10 of 409005 matches for " Ruy J. V.;Barbosa "
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Screening of the odour-activity and bioactivity of the essential oils of leaves and flowers of Hyptis Passerina Mart. from the Brazilian Cerrado
Zellner, Barbara D.;Amorim, Ana Carolina L.;Miranda, Ana Luisa P. de;Alves, Ruy J. V.;Barbosa, Jussara P.;Costa, Gisela L. da;Rezende, Claudia M.;
Journal of the Brazilian Chemical Society , 2009, DOI: 10.1590/S0103-50532009000200018
Abstract: the chemical profile of the essential oils obtained from the leaves and flowers of hyptis passerina mart., a rare species of the brazilian cerrado, has been determined for the first time. analyses by gc-ms showed sesquiterpenes as major compounds. β-epi-acorenol (35.7% and 32.8%, respectively from leaf and flower essential oils), was isolated and identified by 1d and 2d nmr. the flower-derived oil presented a higher concentration of hydrocarbon and oxygenated monoterpenes, while the leaf-oil was richer in diterpenes. the global odour impressions of both oils were given by direct analysis and gc-ms-o and were characterized as herbaceous with tea notes, and green, cooked and woody impressions for leaf-oil; herbaceous, with spicy, woody and minty notes for flower-oil. β-epi-acorenol, spathulenol, β-caryophyllene, and caryophyllene oxide were relevant for the odour-activity of both oils, as well as minor constituents, such as linalool. the antimicrobial activity was investigated by means of agar diffusion disc method and contact bioautography, against gram-positive and negative bacteria and yeast. both oils presented to be bioactive against the tested microorganisms with significant inhibition level.
Formalization of simplification for context-free grammars
Marcus V. M. Ramos,Ruy J. G. B. de Queiroz
Computer Science , 2015,
Abstract: Context-free grammar simplification is a subject of high importance in computer language processing technology as well as in formal language theory. This paper presents a formalization, using the Coq proof assistant, of the fact that general context-free grammars generate languages that can be also generated by simpler and equivalent context-free grammars. Namely, useless symbol elimination, inaccessible symbol elimination, unit rules elimination and empty rules elimination operations were described and proven correct with respect to the preservation of the language generated by the original grammar.
Formalization of closure properties for context-free grammars
Marcus V. M. Ramos,Ruy J. G. B. de Queiroz
Computer Science , 2015,
Abstract: Context-free language theory is a well-established area of mathematics, relevant to computer science foundations and technology. This paper presents the preliminary results of an ongoing formalization project using context-free grammars and the Coq proof assistant. The results obtained so far include the representation of context-free grammars, the description of algorithms for some operations on them (union, concatenation and closure) and the proof of related theorems (e.g. the correctness of these algorithms). A brief survey of related works is presented, as well as plans for further development.
Zizyphus mauritiana Lam. (Rhamnaceae) and the chemical composition of its floral fecal odor
Alves, Ruy J. V.;Pinto, Angelo C.;Costa, Alexandre V. M. da;Rezende, Claudia M.;
Journal of the Brazilian Chemical Society , 2005, DOI: 10.1590/S0103-50532005000400027
Abstract: when in blossom, jujube (zizyphus mauritiana lam., rhamnaceae) emanates a strong fecal odor. the substances responsible for this scent were analysed by headspace solid-phase microextraction and gas chromatography-mass spectrometry (spme-gc-ms) associated to standard co-injection and retention indexes, which showed benzaldehyde as major constituent. minor benzenoids, aliphatic carboxylic acids, aldehydes, hydrocarbons and oxygenated monoterpenes were also observed. olfactometric evaluation of the spme using gc-sniffing port indicated skatole (3-methyl-indole) as responsible for the fecal odor and vanillin for the sweety odor.
Rational solutions from Padé approximants for the generalized Hunter-Saxton equation
H. Aratyn,J. F. Gomes,D. V. Ruy,A. H. Zimerman
Physics , 2014, DOI: 10.1088/1742-6596/474/1/012006
Abstract: Exact rational solutions of the generalized Hunter-Saxton equation are obtained using Pad\'e approximant approach for the traveling-wave and self-similarity reduction. A larger class of algebraic solutions are also obtained by extending a range of parameters within the solutions obtained by this approach.
A Symmetric System of Mixed Painleve III - V Equations and its Integrable Origin
H. Aratyn,J. F. Gomes,D. V. Ruy,A. H. Zimerman
Physics , 2015,
Abstract: A mixed symmetric Painleve III - V model which describes a hybrid of both equations is defined and obtained by successive self-similarity and Dirac Lagrange multiplier reductions from an integrable 4-boson hierarchy.
Formalization of the pumping lemma for context-free languages
Marcus V. M. Ramos,Ruy J. G. B. de Queiroz,Nelma Moreira,José Carlos Bacelar Almeida
Computer Science , 2015,
Abstract: Context-free languages (CFLs) are highly important in computer language processing technology as well as in formal language theory. The Pumping Lemma is a property that is valid for all context-free languages, and is used to show the existence of non context-free languages. This paper presents a formalization, using the Coq proof assistant, of the Pumping Lemma for context-free languages.
Formalization of context-free language theory
Marcus V. M. Ramos,Ruy J. G. B. de Queiroz,Nelma Moreira,José Carlos Bacelar Almeida
Computer Science , 2015,
Abstract: Context-free language theory is a subject of high importance in computer language processing technology as well as in formal language theory. This paper presents a formalization, using the Coq proof assistant, of fundamental results related to context-free grammars and languages. These include closure properties (union, concatenation and Kleene star), grammar simplification (elimination of useless symbols inaccessible symbols, empty rules and unit rules) and the existence of a Chomsky Normal Form for context-free grammars.
The role of behavior in the survival of Biomphalaria glabrata in biossays with the plant molluscicide Phytolacca dodecandra
Jurberg, P.;Barbosa, J. V.;Rotenberg, L.;
Memórias do Instituto Oswaldo Cruz , 1988, DOI: 10.1590/S0074-02761988000100006
Abstract: this work examines the role of behavior in the survival of biomphalaria glabrata exposed to 25, 50 75 and 100 mgl-1 of phytolacca dodecandra. time-lapse cinematography was used to quantify accurately the following parameters: (a) frequency of exits from the solution, (b) time spent out of the solution and (c) time elapsed until the first exit from the solution. these behavior patterns were statistically compared between surviving snails and those which later died. the proportion of surviving snails leaving the liquid medium was significantly higher than that of dying snails. in addition, the surviving group spent significantly more time out of the solution than the group which died, except for the 100 mgl-1 concentration. however, no significant difference was detected in the time elapsed until the first exit from the solution. it can be concluded that both the tendency to leave the p. dodecandra solutions, and the time spent out of them, contributed significantly to snail survival. molluscicide bioassays should take into account the possibility that some behavior patterns of planorbids might contribute to the protection of the snails.
Constituintes químicos voláteis das flores e folhas do pau-brasil (Caesalpinia echinata, Lam.)
Rezende, Claudia M.;Corrêa, Vivian F. S.;Costa, Alexsander V. M.;Castro, Bruno C. S.;Alves, Ruy J. V.;
Química Nova , 2004, DOI: 10.1590/S0100-40422004000300010
Abstract: the volatile constituents obtained from a static cryogenic headspace of caesalpinia echinata lam. (leguminosae) showed e-b-ocimene as the major compound (57.2%), beside other monoterpenes, c6 derivatives like n-hexanal and (e)-2-hexenal and nitrogen compounds such as indole and methyl anthranilate. from the essential oil of the leaves obtained by hydrodistillation in a clevenger apparatus, (e)-3-hexen-1-ol was identified as the major constituent while phenolic compounds were the most representative class of secondary metabolites.
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