12 results on '"Batista, E. R."'
Search Results
2. A Transferable H2O Interaction Potential Based on a Single Center Multipole Expansion: SCME
- Author
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Wikfeldt, K. T., Batista, E. R., Vila, F. D., and Jonsson, H
- Subjects
Physics - Chemical Physics - Abstract
A transferable potential energy function for describing the interaction between water molecules is presented. The electrostatic interaction is described rigorously using a multipole expansion. Only one expansion center is used per molecule to avoid the introduction of monopoles. This single center approach turns out to converge and give close agreement with ab initio calculations when carried out up to and including the hexadecapole. Both dipole and quadrupole polarizability is included. All parameters in the electrostatic interaction as well as the dispersion interaction are taken from ab initio calculations or experimental measurements of a single water molecule. The repulsive part of the interaction is parametrized to fit ab initio calculations of small water clusters and experimental measurements of ice Ih. The parametrized potential function was then used to simulate liquid water and the results agree well with experiment, even better than simulations using some of the point charge potentials fitted to liquid water. The evaluation of the new interaction potential for condensed phases is fast because point charges are not present and the interaction can, to a good approximation, be truncated at a finite range., Comment: 30 pages, 15 figures, 11 tables
- Published
- 2013
- Full Text
- View/download PDF
3. Respostas fisiológicas e metabólicas de duas cultivares de Coffea arabica L. submetidas a atmosferas enriquecidas em CO2 em câmaras de topo aberto e sistema FACE
- Author
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BATISTA, E. R. and EUNICE REIS BATISTA, CNPMA.
- Subjects
Coffee ,Climate change ,Ferrugem alaranjada ,Mudanças climáticas ,Coffea arabica ,Clima ,Hemileia vastatrix ,Café ,Orange rust - Abstract
Resumo: O café é um dos principais produtos de exportação do agronegócio brasileiro, no entanto, as principais variedades de Coffea arabica cultivadas são suscetíveis ao fungo biotrófico Hemileia vastatrix, causador da ferrugem alaranjada, doença que provoca significativas perdas na produção. A atual preocupação com o cenário de mudanças climáticas tem motivado a realização de estudos sobre impactos das alterações ambientais previstas no cultivo cafeeiro e na interação planta-patógeno. Este trabalho teve por objetivos avaliar o efeito de atmosferas enriquecidas de CO 2 em Coffea arabica comparando-se as cultivares Catuaí vermelho IAC-144 e Obatã vermelho IAC-1669, respectivamente suscetível e resistente à ferrugem. Foram conduzidos três experimentos, sendo dois deles em Câmaras de Topo Aberto (Open Top Chambers, OTCs) nas concentrações atmosféricas ambiente (380ppm) e o de elevado CO 2 (760 ppm), com duração de 100 e 45 dias, respectivamente, e com inoculação dos cafeeiros pelo fungo Hemileia vastatrix apenas no segundo experimento. O 3o experimento foi realizado sob condições de campo no primeiro sistema de enriquecimento atmosférico de CO 2 ao ar livre (FACE) da América Latina instalado no campus experimental da Embrapa Meio Ambiente de Jaguariúna, SP, no qual os cafeeiros das duas cultivares foram submetidos a concentrações atual (~380ppm) e de 550 ppm de CO 2 ao longo de 27 meses de cultivo. No primeiro experimento, realizado em OTCs, foi observado aumento nas taxas de assimilação de carbono sob condições de elevado CO 2, principalmente na cultivar Catuaí, porém sem efeitos significativos sobre o crescimento. Os teores de carboidratos aumentaram até os 46 dias, sendo que a cv. Catuaí acumulou maiores teores de glucose e frutose enquanto a cv. Obatã acumulou maiores teores de amido. A aclimatação fotossintética ocorreu simultaneamente ao acúmulo de amido, sendo observada redução dos teores de nitrogênio nas duas cultivares. Os teores de 15 N e C variaram de acordo com a disponibilidade de CO 2 atmosférico, com reflexos significativos na composição isotópica e de discriminação isotópica do carbono. No segundo experimento, as medidas de taxas de fotossíntese realizadas após o ciclo da infecção pelo fungo H. vastatrix foram maiores em todos os cafeeiros cultivados na concentração elevada de CO 2 . Também foram verificados aumentos dos teores de açúcares solúveis totais (AST), amido, fenólicos solúveis totais (FST) e lignina e diminuição dos teores de glucose, frutose, sacarose, rafinose, estaquiose e de açúcares redutores (AR) em cafeeiros suscetíveis (Catuaí) não inoculados com o patógeno. Quando foram inoculados com o patógeno, esses cafeeiros, apresentaram redução dos teores de AST, glucose, frutose e lignina e elevação dos teores de AR e amido e não apresentaram variações nos teores de sacarose, rafinose e estaquiose. Não foi observada alteração na severidade dos sintomas causados por Hemileia vastatrix nos cafeeiros suscetíveis crescidos em alto de CO 2 em comparação com aqueles mantidos na concentração atmosférica ambiente. O 3o experimento indicou que o aumento da concentração atmosférica de CO 2 nos cafeeiros cultivados no sistema FACE não influenciou significativamente as concentrações foliares de carboidratos, de fenólicos solúveis totais e de lignina, nas duas cultivares ao longo do período de 27 meses. Por outro lado, propiciou o aumento das taxas de fotossíntese do cafeeiro, principalmente no período quente e úmido, contribuindo ainda para a elevação da eficiência intrínseca do uso da água. Adicionalmente, o aumento da discriminação isotópica de carbono indicou influência positiva da maior concentração atmosférica de CO 2 na assimilação de carbono em todos os cafeeiros. Em resumo, as cultivares de cafeeiro estudadas responderam ao incremento da concentração atmosférica de CO 2 com aumento na fotossíntese, porém este incremento não resultou em melhora de resistência ao fungo causador da ferrugem do café quando cultivado em OTCs. Abstract: Coffee is one of the main comodities of the Brazilian agribusiness but most cultivars of Coffea arabica are susceptible to the fungus Hemileia vastatrix, the causal agent of the coffee rust disease, with negative impacts on coffee prodution. The current concerns with the scenario of climate changes have stimulated studies on impacts of environmental changes on coffee cultivation and its interaction with the pathogen. This work aimed to evaluate the effect of CO 2 -enriched atmospheres on two cultivars of Coffea arabica, comparing the suscetible cultivar red Catuaí 144 IAC with the resistant one IAC 1669 red Obatã. Three different experiments were carried out, two of them in Open Top Chambers (OTCs) under ambient (380ppm) and high CO 2 atmosphere (760 ppm), for 100 and 45 days, respectively, and the second one with H. vastatrix inoculation. The third experiment was performed under field conditions in the first free air CO 2 enrichment (FACE) system in Latin America, installed in the Embrapa Meio Ambiente, Jaguariúna, SP, Brazil, in which coffee cultivars were subjected to current concentration (~ 380ppm) and CO 2 - enriched atmosphere (550 ppm) for 27 months. We evaluated the net carbon assimilation rates and the contents of primary and secondary metabolites. In the first experiment conducted in OTCs, an increase in carbon assimilation was observed under high CO 2 conditions, mainly in the cultivar Catuaí, but without significant effects on growth. Carbohydrate levels increased until the 46 th day, with accumulation of glucose and fructose in the Catuaí cultivar when compared with the Obatã, which stored predominantly starch. The photosynthetic acclimation occurred simultaneously to the accumulation of starch, following the reduction in the levels of nitrogen in both cultivars. The levels of 15 N and C varied according to the availability of atmospheric CO 2 , with significant effects on isotopic composition and carbon isotope discrimination. In the second experiment, the net photosynthetic assimilation was measured after infection by the fungus H. vastatrix, being higher in both cultivars under elevated CO 2 . Increased levels of total soluble sugars (AST), starch, soluble total phenolic (FST) and lignin and reduction of glucose, fructose, sucrose, raffinose, stachyose and reducing sugars (AR) were observed in susceptible coffee (Catuaí) not inoculated with the pathogen. Plant inoculation with the pathogen led to a reduction in the levels of AST, glucose, fructose and lignina and increasing in AST and starch with no changes in sucrose, raffinose and stachyose. No changes were observed in the severity of symptoms caused by H. vastatrix on the susceptible cultivar under high CO 2 when compared to ambient atmospheric concentration. The third experiment indicated that the atmospheric CO 2 concentration in the FACE system did not influence significantly the foliar concentrations of carbohydrates, total soluble phenolic and lignin, in both cultivars over the period of 27 months. On the other hand, the increase in the atmospheric CO 2 led to increased of photosynthesis rates of the coffee trees, mainly during warm and rainy seasons, contributing to the elevation of the intrinsic water use efficiency. Additionally, the increased carbon isotope discrimination indicated positive influence of increased atmospheric CO 2 concentration in carbon assimilation in both cultivars. In conclusion, the coffee cultivars responded to the elevated atmospheric CO 2 concentration increasing photosynthesis, but this increase did not result in resistance improvement to the coffee rust fungus when coffee was grown on OTCs. Tese (Doutorado) - Instituto de Botânica da Secretaria de Estado do Meio Ambiente, São Paulo.
- Published
- 2015
4. A transferable H2O interaction potential based on a single center multipole expansion: SCME
- Author
-
Wikfeldt, K. T., primary, Batista, E. R., additional, Vila, F. D., additional, and Jónsson, H., additional
- Published
- 2013
- Full Text
- View/download PDF
5. Circularly polarized photoluminescence from platinum porphyrins in organic hosts: Magnetic field and temperature dependence
- Author
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Diaconu, C. V., primary, Batista, E. R., additional, Martin, R. L., additional, Smith, D. L., additional, Crone, B. K., additional, Crooker, S. A., additional, and Smith’s, D. L., additional
- Published
- 2011
- Full Text
- View/download PDF
6. A transferable H2O interaction potential based on a single center multipole expansion: SCME.
- Author
-
Wikfeldt, K. T., Batista, E. R., Vila, F. D., and Jónsson, H.
- Abstract
A transferable potential energy function for describing the interaction between water molecules is presented. The electrostatic interaction is described rigorously using a multipole expansion. Only one expansion center is used per molecule to avoid the introduction of monopoles. This single center approach turns out to converge and give close agreement with ab initio calculations when carried out up to and including the hexadecapole. Both dipole and quadrupole polarizability are included. All parameters in the electrostatic interaction as well as the dispersion interaction are taken from ab initio calculations or experimental measurements of a single water molecule. The repulsive part of the interaction is parametrized to fit ab initio calculations of small water clusters and experimental measurements of ice I
h . The parametrized potential function was then used to simulate liquid water and the results agree well with experiment, even better than simulations using some of the point charge potentials fitted to liquid water. The evaluation of the new interaction potential for condensed phases is fast because point charges are not present and the interaction can, to a good approximation, be truncated at a finite range. [ABSTRACT FROM AUTHOR]- Published
- 2013
- Full Text
- View/download PDF
7. No evidence of the 17-keV neutrino in the decay ofGe71
- Author
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DiGregorio, D. E., primary, Gil, S., additional, Huck, H., additional, Batista, E. R., additional, Ferrero, A. M. J., additional, and Gattone, A. O., additional
- Published
- 1993
- Full Text
- View/download PDF
8. A Self-Consistent Charge-Embedding Methodology for ab Initio Quantum Chemical Cluster Modeling of Ionic Solids and Surfaces: Application to the (001) Surface of Hematite (α-Fe<INF>2</INF>O<INF>3</INF>)
- Author
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Batista, E. R. and Friesner, R. A.
- Abstract
To ab initio simulate an ionic crystal using a cluster of atoms, one must surround that cluster with point charges. These point charges add the effect of the electrostatic potential of the rest of the crystal on the electronic structure of the quantum cluster. The value of the point charges has to be chosen to reproduce the crystal field in the region of the cluster. In this work, a method to compute the necessary point charges is presented. The algorithm to choose the point charges is an extension of the one presented by Derenzo et al. [J. Chem. Phys.
2000 , 112, 2074]. The method consists of a self-consistent loop, fitting in each iteration the value of the point charges to reproduce the electrostatic field, calculated from the quantum simulation, in the region of the cluster. This method was then applied to the study of the (001) basal surface of hematite, α-Fe2 O3 . As the cluster size is systematically increased, it is shown that to fully converge the electrostatic effect on the electronic structure of the cluster, clusters of the order of 60 atoms are necessary. As a convergence parameter for the cluster to the bulk behavior, we used the ionization energy of the cluster. In the limit of an infinite cluster, we obtained the work function of hematite to be 5.6 eV.- Published
- 2002
- Full Text
- View/download PDF
9. Diffusion and Island formation on the ice Ih basal plane surface
- Author
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Batista, E. R. and Jonsson, H.
- Published
- 2001
- Full Text
- View/download PDF
10. Non-aqueous transuranic coordination chemistry
- Author
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Gaunt, A. J., Schnaars, D. D., Neu, M. P., Scott, B. L., May, I., Reilly, S. D., Hayton, T. W., Kaltsoyannis, N., Ingram, K. I. M., Batista, E. R., Ibers, J. A., Peterman, D. R., Kozimor, S. A., James Boncella, and Enriquez, A. E.
11. Covalency trends for d- and f-element metallocene dichlorides determined from chlorine K-edge x-ray absorption spectroscopy and time dependent-density functional theory
- Author
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Kozimor, S. A., Yang, P., Batista, E. R., Boland, K. S., Burns, C. J., Clark, D. L., Conradson, S. D., Martin, R. L., Marianne Wilkerson, and Wolfsberg, L. E.
12. The MOD-QM/MM Method: Applications to Studies of Photosystem II and DNA G-Quadruplexes.
- Author
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Askerka M, Ho J, Batista ER, Gascón JA, and Batista VS
- Subjects
- Animals, Crystallography, X-Ray, Eukaryota metabolism, Humans, Magnetic Resonance Spectroscopy, Static Electricity, G-Quadruplexes, Molecular Dynamics Simulation, Photosystem II Protein Complex chemistry, Quantum Theory
- Abstract
Quantum mechanics/molecular mechanics (QM/MM) hybrid methods are currently the most powerful computational tools for studies of structure/function relations and catalytic sites embedded in macrobiomolecules (eg, proteins and nucleic acids). QM/MM methodologies are highly efficient since they implement quantum chemistry methods for modeling only the portion of the system involving bond-breaking/forming processes (QM layer), as influenced by the surrounding molecular environment described in terms of molecular mechanics force fields (MM layer). Some of the limitations of QM/MM methods when polarization effects are not explicitly considered include the approximate treatment of electrostatic interactions between QM and MM layers. Here, we review recent advances in the development of computational protocols that allow for rigorous modeling of electrostatic interactions in biomacromolecules and structural refinement, beyond the common limitations of QM/MM hybrid methods. We focus on photosystem II (PSII) with emphasis on the description of the oxygen-evolving complex (OEC) and its high-resolution extended X-ray absorption fine structure spectra (EXAFS) in conjunction with Monte Carlo structural refinement. Furthermore, we review QM/MM structural refinement studies of DNA G4 quadruplexes with embedded monovalent cations and direct comparisons to NMR data., (© 2016 Elsevier Inc. All rights reserved.)
- Published
- 2016
- Full Text
- View/download PDF
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