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Search Results: 1 - 10 of 17362 matches for " Catarina Carvalho;Mazzoni-Viveiros "
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Avalia??o da eficiência da propaga??o de Alcantarea imperialis (Bromeliaceae) cultivada in vitro e ex vitro
Aoyama, Elisa Mitsuko;Versieux, Leonardo de Melo;Nievola, Catarina Carvalho;Mazzoni-Viveiros, Solange Cristina;
Rodriguésia , 2012, DOI: 10.1590/S2175-78602012000200007
Abstract: the in vitro cultivation of bromeliads has been considered an effective technique to improve its production. however, there are no studies that compare the efficiency of the methods of in vitro propagation versus ex vitro for the brazilian giant bromeliad alcantarea imperialis (carrière) harms used in landscaping and considered to be endangered due to illegal extraction. the in vitro culture appears as a good alternative to preserve the genetic diversity of this polymorphic species, assuring that the raw material for the contemporary evolution will be available. the aim of this study was to compare the growth of plants of a. imperialis in vitro and ex vitro obtained from seed, establishing the ideal transfer period. the seeds were disinfected before being transferred to culture conditions (culture medium or pinus sp. bark substrate). after the pre-established growing time, in vitro plants were transferred to ex vitro (acclimatization). plants from in vitro cultures showed higher values for all measured parameters compared to those grown ex vitro. the data showed that the acclimation of plants cultivated in vitro for 2, 4, and 6 months showed better growth compared to those acclimated after being cultured in vitro for longer time. these results show the efficiency of the in vitro culture method, indicating the ideal time for the maintenance of the plants in nutrient media, providing important cost-benefit ratio for production.
Efeitos da polui??o aérea e edáfica no sistema radicular de Tibouchina pulchra Cogn. (Melastomataceae) em área de Mata Atlantica: associa??es micorrízicas e morfologia
Mazzoni-Viveiros, Solange C.;Trufem, Sandra F.B.;
Brazilian Journal of Botany , 2004, DOI: 10.1590/S0100-84042004000200013
Abstract: the effects of atmospheric pollutants, originated from the industrial region of cubat?o, s?o paulo state, were analysed on plants of tibouchina pulchra from three areas with different types of pollutants. root systems were used from passive and active monitoring specimens, and open-top-chambers (filtrated and no-filtrated air) specimens too. it was possible to evaluate the quantitative data from the root systems, the vesicular-arbuscular mycorrhizae (vam) diversity, the mycorrhizal colonization percentage and the spores quantity in the rhizosphere soil. the results showed that in the most polluted area the specimens have: - increase in the mycorrhizal colonization percentages; - more vam species diversity and quantity; - redution tendency in the root system development, especially in the wood roots length; - increase tendency in the fine roots quantity. these results demonstrate that the species studied is tolerant to the stress caused from the pollutants, with redution of the tolerance when the action of atmospheric pollutants takes place together the action of soil pollutants.
Development and some histochemical aspects of foliar glandular trichomes of Stevia rebaudiana (Bert.) Bert. - Asteraceae
MONTEIRO, WALKYRIA ROSSI;CASTRO, MARíLIA DE MORAES;MAZZONI-VIVEIROS, SOLANGE CRISTINA;MAHLBERG, PAUL GORDON;
Brazilian Journal of Botany , 2001, DOI: 10.1590/S0100-84042001000300013
Abstract: the ten-celled biseriate glandular trichome of stevia rebaudiana (bert.) bert.-asteraceae, found on both leaf surfaces, originates from a single protruding, protodermal cell undergoing an anticlinal division. a subsequent series of periclinal divisions, occurring in acropetal sequence, leads to the formation of the trichome, composed of five pairs of cells, one pair of basal cells, another of stalk cells and three pairs of secretory head cells. developing, still two-celled glandular trichomes already occur on leaf primordia of the second pair (these primordia measuring, in some cases, ca. 0.30 mm in length), and most of the glandular trichomes are at the mature phase on very young, expanding leaves, for example on those of the sixth pair. the secretory material released by the head cells is stored in the trichome cavity (subcuticular space). basic histochemical tests reveal that such material is lipophilic (mainly) and hydrophilic in nature.
Development and some histochemical aspects of foliar glandular trichomes of Stevia rebaudiana (Bert.) Bert. - Asteraceae
MONTEIRO WALKYRIA ROSSI,CASTRO MARíLIA DE MORAES,MAZZONI-VIVEIROS SOLANGE CRISTINA,MAHLBERG PAUL GORDON
Brazilian Journal of Botany , 2001,
Abstract: The ten-celled biseriate glandular trichome of Stevia rebaudiana (Bert.) Bert.-Asteraceae, found on both leaf surfaces, originates from a single protruding, protodermal cell undergoing an anticlinal division. A subsequent series of periclinal divisions, occurring in acropetal sequence, leads to the formation of the trichome, composed of five pairs of cells, one pair of basal cells, another of stalk cells and three pairs of secretory head cells. Developing, still two-celled glandular trichomes already occur on leaf primordia of the second pair (these primordia measuring, in some cases, ca. 0.30 mm in length), and most of the glandular trichomes are at the mature phase on very young, expanding leaves, for example on those of the sixth pair. The secretory material released by the head cells is stored in the trichome cavity (subcuticular space). Basic histochemical tests reveal that such material is lipophilic (mainly) and hydrophilic in nature.
Anatomia do escapo e rizoma de espécies brasileiras de Bulbostylis Kunth (Cyperaceae)
Prata, Ana Paula;Menezes, Nanuza Luiza de;Mazzoni-Viveiros, Solange C.;Wanderley, Maria das Gra?as L.;Thomas, William Wayt;
Brazilian Journal of Botany , 2007, DOI: 10.1590/S0100-84042007000200009
Abstract: bulbostylis kunth (subfamily cyperoideae) comprises approximately 150 species with centers of distribution in south america and africa. the anatomy of the scapes was studied in 40 species of bulbostylis. the characters found to be of taxonomic value in the key species are: the shape of the scape in transverse section, the presence of ribs and furrows, the aspect of the epidermal cells and stomata, the shape of the cortical sclerenchymatous strands, the number of vascular unit, a fistulose medulla, and the occurrence of radiate parenchyma. these characters were found to be diagnostically useful at the specific level. we also show that the scape should be considered a monostele. the atactostele appears in the rhizome.
Cobordism invariance of the family index
Catarina Carvalho
Mathematics , 2008,
Abstract: We give a K-theory proof of the invariance under cobordism of the family index. We consider elliptic pseudodifferential families on a continuous fibre bundle with smooth fibres over a compact base space B, and define a notion of cobordant families using K^1-groups on fibrations with boundary. We show that the index of two such families is the same using properties of the push-forward map in K-theory to reduce it to families on B x R^n.
A K-Theory Proof of the Cobordism Invariance of the Index
Catarina Carvalho
Mathematics , 2004,
Abstract: We give a proof of the cobordism invariance of the index of elliptic pseudodifferential operators on sigma-compact manifolds, where, in the non-compact case, the operators are assumed to be multiplication outside a compact set. We show that, if the principal symbol class of such an elliptic operator on the boundary of a manifold X has a suitable extension to K^1(TX), then its index is zero. This condition is incorporated into the definition of a cobordism group for non-compact manifolds, called here ``cobordism of symbols''. Our proof is topological, in that we use properties of the push-forward map in K-theory defined by Atiyah and Singer, to reduce it to R^n. In particular, we generalize the invariance of the index with respect to the push-forward map to the non-compact case, and obtain an extension of the K-theoretical index formula of Atiyah and Singer to operators that are multiplication outside a compact set. Our results hold also for G-equivariant operators, where G is a compact Lie group.
Layer potentials C*-algebras of domains with conical points
Catarina Carvalho,Yu Qiao
Mathematics , 2011,
Abstract: To a domain with conical points \Omega, we associate a natural C*-algebra that is motivated by the study of boundary value problems on \Omega, especially using the method of layer potentials. In two dimensions, we allow \Omega to be a domain with ramified cracks. We construct an explicit groupoid associated to the boundary of \Omega and use the theory of pseudodifferential operators on groupoids and its representations to obtain our layer potentials C*-algebra. We study its structure, compute the associated K-groups, and prove Fredholm conditions for the natural pseudodifferential operators affiliated to this C*-algebra.
On Algebras with many symmetric operations
Catarina Carvalho,Andrei Krokhin
Mathematics , 2014,
Abstract: We show that, for each finite algebra A, either it has symmetric term operations of all arities or else some finite algebra in the variety generated by A has two automorphisms without a common fixed point. We also show this two-automorphism condition cannot be replaced by a single fixed-point- free automorphism.
An index formula for perturbed Dirac operators on Lie manifolds
Catarina Carvalho,Victor Nistor
Mathematics , 2011,
Abstract: We give an index formula for a class of Dirac operators coupled with unbounded potentials. More precisely, we study operators of the form P := D+ V, where D is a Dirac operators and V is an unbounded potential at infinity on a possibly non-compact manifold M_0. We assume that M_0 is a Lie manifold with compactification denoted M. Examples of Lie manifolds are provided by asymptotically Euclidean or asymptotically hyperbolic spaces. The potential V is required to be invertible outside a compact set K and V^{-1} extends to a smooth function on M\K that vanishes on all faces of M in a controlled way. Using tools from analysis on non-compact Riemannian manifolds, we show that the computation of the index of P reduces to the computation of the index of an elliptic pseudodifferential operator of order zero on M_0 that is a multiplication operator at infinity. The index formula for P can then be obtained from earlier results. The proof also yields similar index formulas for Callias-type pseudodifferential operators coupled with bounded potentials that are invertible at infinity on asymptotically commutative Lie manifolds, a class of manifolds that includes the scattering and double-edge calculi.
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