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Search Results: 1 - 10 of 36429 matches for " Jose Roberto Rios Leite "
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Mapping of focused Laguerre-Gauss beams: The interplay between spin and orbital angular momentum and its dependence on detector characteristics
Vasily V. Klimov,Daniel Bloch,Martial Ducloy,Jose Roberto Rios Leite
Physics , 2012,
Abstract: We show that propagating optical fields bearing an axial symmetry are not truly hollow in spite of a null electric field on-axis. The result, obtained by general arguments based upon the vectorial nature of electromagnetic fields, is of particular significance in the situation of an extreme focusing, when the paraxial approximation no longer holds. The rapid spatial variations of fields with a "complicated" spatial structure are extensively analyzed in the general case and for a Laguerre-Gauss beam 2 as well, notably for beams bearing a |l| = 2 orbital angular momentum for which a magnetic field and a gradient of the electric field are present on-axis. We thus analyze the behavior of a atomic size light-detector, sensitive as well to quadrupole electric transitions and to magnetic dipole transitions, and apply it to the case of Laguerre-Gauss beam. We detail how the mapping of such a beam depends on the nature and on the specific orientation of the detector. We show also that the interplay of mixing of polarization and topological charge, respectively associated to spin and orbital momentum when the paraxial approximation holds, modifies the apparent size of the beam in the focal plane. This even leads to a breaking of the cylindrical symmetry in the case of a linearly polarized transverse electric field.
Do entangled photons induce two-photon two-atom transitions more efficiently than other states of light ?
Zhan Zheng,Pablo L. Saldanha,Jose R. Rios Leite,Claude Fabre
Physics , 2013,
Abstract: We study in this paper the efficiency of different two-photon states of light to induce the simultaneous excitation of two atoms of different kinds when the sum of the energies of the two photons matches the sum of the energies of the two atomic transitions, while no photons are resonant with each individual transition. We find that entangled two-photon states produced by an atomic cascade are indeed capable of enhancing by a large factor the simultaneous excitation probability as compared to uncorrelated photons, as predicted some years ago by Muthukrishnan et al, but that several non-entangled, separable, correlated states, produced either by an atomic cascade or parametric down conversion, or even appropriate combinations of coher- ent states, have comparable efficiencies. We show that the key ingredient for the increase of simultaneous excitation probability is the presence of strong frequency anti-correlation and not time correlation nor time-frequency entanglement.
Disseminated histoplasmosis and primary central nervous system lymphoma
Lambertucci José Roberto,Fran?a Bruno Mour?o,Leite Virgínia Hora Rios
Revista da Sociedade Brasileira de Medicina Tropical , 2004,
Scanning electron microscopy of the egg and the first instar larva of Dermatobia hominis (Diptera, cuterebridae)
Leite, Antonio Cesar Rios;
Memórias do Instituto Oswaldo Cruz , 1988, DOI: 10.1590/S0074-02761988000200017
Abstract: the egg and the first instar larva of dermatobia hominis were described based on observation with a scanning electron microscope.
índice relativo de clorofila e o estado nutricional em nitrogênio durante o ciclo do cafeeiro fertirrigado
Godoy, Leandro Jose Grava de;Santos, Thiago da Silva;Villas B?as, Roberto Lyra;Leite Júnior, Jo?o Batista;
Revista Brasileira de Ciência do Solo , 2008, DOI: 10.1590/S0100-06832008000100021
Abstract: the chlorophyll meter (spad-502, minolta) is a portable device that measures the relative chlorophyll index (rci) in a simple, fast and non-destructive way in the field. this index is correlated with leaf n concentration in several crops, and allows the correction of n deficiency, optimizing fertigation. the objective of this study was to test rci as an indicator of the nitrogen status in coffee trees to adjust fertigation during the development cycle. the experiment was carried out in botucatu, state of s?o paulo, brazil, in an area with two-year old coffee plants of cultivar "red catuaí", spaced at 2.5 x 0.8 m, under drip irrigation. the experiment had a randomized block design with four replications and five treatments: control treatment under irrigation and without fertilization, and four n rates using fertigation with 33, 66, 100, and 133 % of the recommended annual n rate (52.8; 105.6; 160.0 and 212.7 kg ha-1, respectively). the fertilizer treatments were split in weakly applications. the rci increased linearly with the n rates and the yield was significantly correlated with rci, from flowering to harvest. however, there was no correlation between beans yield with the leaf n concentration. the rcis of high yielding coffee plants were 81.5-83.2 (flowering and beginning of fruit filling), 76.2-78.3 (fruit expansion) 68.3 - 69.8 (beginning of grain formation), 64.0-65.9 (during grain formation) and 61.7-62.7 spad units (grain maturation). the chlorophyll meter can be used throughout the coffee development cycle to define the likelihood of n response in coffee trees.
Ultrastructure of the male terminalia of Cochliomyia hominivorax and C. macellaria
Leite, Ant?nio Cesar Rios;
Memórias do Instituto Oswaldo Cruz , 1995, DOI: 10.1590/S0074-02761995000400008
Abstract: cochliomyia hominivorax and c. macellaria are species that cause primary and secondary myiasis, respectively of medical and veterinary importance in the new world. the male terminalia of both insects show morphological differences that are now described from scanning electron microscope (sem) observations.
Ultrastructure of the adults of Bunostomum phlebotomum (Nematoda: Ancylostomatidae)
Leite, Ant?nio Cesar Rios;
Memórias do Instituto Oswaldo Cruz , 1992, DOI: 10.1590/S0074-02761992000500025
Abstract: the morphology of the male and female of bunostomum phlebotomum are described based on scanning electron microscope (sem) observations. the attachment of the worms to the small intestinal mucosa and during the copula were observed. structures of the bucal capsule and genital organs were also studied.
Computational Termochemistry Study of the C80 Isomers and Their Endo Lanthanum Complexes by Applying Homodesmotic and Isodesmic Reactions
Citlalli Rios,Roberto Salcedo
Molecules , 2012, DOI: 10.3390/molecules171214588
Abstract: C80 is a fullerene species which appears in different isomeric configurations. A general homodesmotic reaction previously designed to study the energy of fullerenes was implemented, in order to analyze the energy of this family of isomers. These results concur with some of the experimental data, but energy differences referring to all the configurations yield novel propositions about their particular behavior. The corresponding lanthanum complexes are also analyzed here and a new isodesmic reaction was designed for this particular case.
Urinary glycosaminoglycans excretion and the effect of dimethyl sulfoxide in an experimental model of non-bacterial cystitis
Soler, Roberto;Bruschini, Homero;Truzzi, Jose C.;Martins, Joao R.;Camara, Niels O.;Alves, Maria T.;Leite, Katia R.;Nader, Helena B.;Srougi, Miguel;Ortiz, Valdemar;
International braz j urol , 2008, DOI: 10.1590/S1677-55382008000400013
Abstract: purpose: we reproduced a non-bacterial experimental model to assess bladder inflammation and urinary glycosaminoglycans (gag) excretion and examined the effect of dimethyl sulfoxide (dmso). materials and methods: female rats were instilled with either protamine sulfate (ps groups) or sterile saline (control groups). at different days after the procedure, 24 h urine and bladder samples were obtained. urinary levels of hyaluronic acid (ha) and sulfated glycosaminoglycans (s-gag) were determined. also to evaluate the effect of dmso animals were instilled with either 50% dmso or saline 6 hours after ps instillation. to evaluate the effect of dmso in healthy bladders, rats were instilled with 50% dmso and controls with saline. results: in the ps groups, bladder inflammation was observed, with polymorphonuclear cells during the first days and lymphomononuclear in the last days. ha and s-gag had 2 peaks of urinary excretion, at the 1st and 7th day after ps injection. dmso significantly reduced bladder inflammation. in contrast, in healthy bladders, dmso produced mild inflammation and an increase in urinary ha levels after 1 and 7 days and an increase of s-gag level in 7 days. animals instilled with ps and treated with dmso had significantly reduced levels of urinary ha only at the 1st day. urinary s-gag/cr levels were similar in all groups. conclusions: increased urinary levels of gag were associated with bladder inflammation in a ps-induced cystitis model. dmso significantly reduced the inflammatory process after urothelial injury. conversely, this drug provoked mild inflammation in normal mucosa. dmso treatment was shown to influence urinary ha excretion.
Chemotherapy-induced hemorrhagic cystitis: pathogenesis, pharmacological approaches and new insights
Ronaldo A. Ribeiro,Roberto C.P. Lima-Junior,Caio Abner V.G. Leite,Jose Mauricio S.C. Mota
Journal of Experimental and Integrative Medicine , 2012,
Abstract: Chemotherapy-induced hemorrhagic cystitis (HC) remains a common and life-threatening clinical complication, mainly due to the increasing usage of alkylating agents during conditioning regimen for hematopoietic cell transplantation. Currently, mesna and hyperhydration are the two more employed preventive measures. However, these prophylactic approaches have been proven not to be completely effective, since cystoscopic and histopathologic bladder damage are evidenced. Therefore, understanding the pathogenesis of HC must be the cornerstone for the development of novel therapeutic strategies. The purpose of this review is to examine the current knowledge regarding the pathogenesis of HC, describing the importance of transcription factors (nuclear factor kappaB), cytokines (tumor necrosis factor-α, interleukin-1β, -4, -6, and -8), enzymes (inducible nitric oxide synthase and cyclooxygenase-2), among other mediators, for the bladder injury. We also discuss the currently available animal models and future perspectives on the management of HC. [J Exp Integr Med 2012; 2(2.000): 95-112]
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