Molecular and serological detection of Ehrlichia canis and Babesia vogeli in dogs in Colombia

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Sliding Vector Fields via Slow-Fast Systems

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

On Duffin-Kemmer-Petiau particles with a mixed minimal-nonminimal vector coupling and the nondegenerate bound-states for the one-dimensional inversely linear background

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

VECTOR FIELDS TANGENT TO FOLIATIONS

We investigate in this paper the topological stability of pairs (omega, X), where w is a germ of an integrable 1-form and X is a germ of a vector field tangent to the foliation determined by omega.

Use of In Vivo and In Vitro Systems to Select Leishmania amazonensis Expressing Green Fluorescent Protein

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Host-parasite relationships in paracoccidioidomycosis

A viewpoint of host-parasite relationships in paracoccidioidomycosis is presented. The characteristics of the fungus which are important to the host-parasite interaction are discussed. Aspects of inhibition of mycelium-to-yeast transformation by estrogens acting at receptors on the fungal wall and in the cytoplasm, and the role of polysaccharide components of the cell wall in virulence are reviewed. The natural mechanisms of host defense are also examined, including phagocytosis, complement system, natural-killer cells and genetic control of resistance and susceptibility. Finally, a discussion of granuloma morphogenesis and its relationship to the humoral and cellular anti-P. brasiliensis immune response is presented.

Vector meson mixing and charge symmetry violation

We discuss the consistency of the traditional vector meson dominance (VMD) model for photons coupling to matter, with the vanishing of vector meson-meson and meson-photon mixing self-energies at q2 = 0. This vanishing of vector mixing has been demonstrated in the context of rho-omega mixing for a large class of effective theories. As a further constraint on such models, we here apply them to a study of photon-meson mixing and VMD. As an example we compare the predicted momentum dependence of one such model with a momentum-dependent version of VMD discussed by Sakurai in the 1960's. We find that it produces a result which is consistent with the traditional VMD phenomenology. We conclude that comparison with VMD phenomenology can provide a useful constraint on such models.

Henneguya piaractus n.sp. (Myxozoa: Myxobolidae), a gill parasite of Piaractus mesopotamicus Holmberg, 1887 (Osteichthyes: characidae), in Brazil

Henneguya piaractus n.sp. was found from the gill filaments of Piaractus mesopotamicus (Characidae). Fishes were collected during a year from the reservoir at Centro de Aquicultura da UNESP, Jaboticabal, SP, Brazil. The prevalence of this parasite was 97.3% in the gills of farmed fish. Observations on spore development into the cysts were done. Studies with scanning electon microscopy were performed to observe the spore and cyst structure.

Signal and backgrounds for the single production of scalar and vector leptoquarks at the CERN LHC

We perform a detailed analysis of the potentiality of the CERN Large Hadron Collider to study the single production of leptoquarks via pp→e±q→ leptoquark →e± q, with e± generated by the splitting of photons radiated by the protons. Working with the most general SU(2)L⊗U( 1 )Y invariant effective Lagrangian for scalar and vector leptoquarks, we analyze in detail the leptoquark signals and backgrounds that lead to a final state containing an e± and a hard jet with approximately balanced transverse momenta. Our results indicate that the LHC will be able to discover leptoquarks with masses up to 2-3 TeV, depending on their type, for Yukawa couplings of the order of the electromagnetic one.

Strongly interacting vector bosons at the CERN LHC: Quartic anomalous couplings

We analyze the potential of the CERN Large Hadron Collider to study anomalous quartic vector-boson interactions through the production of vector-boson pairs accompanied by jets. In the framework of SU(2) L⊗U(1) Y chiral Lagrangians, we examine all effective operators of order p 4 that lead to new four-gauge-boson interactions but do not alter trilinear vertices. In our analyses, we perform the full tree-level calculation of the processes leading to two jets plus vector-boson pairs, W +W -,W ±W ±,W ±Z, or ZZ, taking properly into account the interference between the standard model and the anomalous contributions. We obtain the bounds that can be placed on the anomalous quartic interactions and we study the strategies to distinguish the possible new couplings. ©1998 The American Physical Society.

Signal and backgrounds for leptoquarks at the CERN LHC. II. Vector leptoquarks

We perform a detailed analyses of the CERN Large Hadron Collider (LHC) capability to discover first generation vector leptoquarks through their pair production. We study the leptoquark signals and backgrounds that give rise to final states containing a pair e+e- and jets. Our results show that the LHC will be able to discover vector leptoquarks with masses up to 1.8-2.3 TeV depending on their couplings to fermions and gluons. ©1999 The American Physical Society.

Off-diagonal helicity density matrix elements for vector mesons produced in polarized e+e- processes

Final-state qq̄ interactions give origin to nonzero values of the off-diagonal element ρ1,-1 of the helicity density matrix of vector mesons produced in e+e- annihilations, as has been confirmed by recent OPAL data on φ, D*, and K*. New predictions are given for ρ1,-1 of several mesons produced at large XE and small pT - i.e., collinear with the parent jet - in the annihilation of polarized e+ and e-; the results depend strongly on the elementary dynamics and allow further nontrivial tests of the standard model.

Necessary conditions of optimality for vector-valued impulsive control problems

A vector-valued impulsive control problem is considered whose dynamics, defined by a differential inclusion, are such that the vector fields associated with the singular term do not satisfy the so-called Frobenius condition. A concept of robust solution based on a new reparametrization procedure is adopted in order to derive necessary conditions of optimality. These conditions are obtained by taking a limit of those for an appropriate sequence of auxiliary standard optimal control problems approximating the original one. An example to illustrate the nature of the new optimality conditions is provided. © 2000 Elsevier Science B.V. All rights reserved.

Left-right asymmetries and exotic vector-boson discovery in lepton-lepton colliders

By considering left-right (L-R) asymmetries we study the capabilities of lepton colliders in searching for new exotic vector bosons. Specifically we study the effect of a doubly charged bilepton boson and an extra neutral vector boson appearing in a 3-3-1 model on the L-R asymmetries for the processes e-e- → e-e-, μ-μ- → μ-μ- and e-μ- → e-μ- and show that these asymmetries are very sensitive to these new contributions and that they are in fact powerful tools for discovery of this sort of vector bosons.

Mebendazole treatment against Anacanthorus penilabiatus (Monogenea, Dactylogyridae) gill parasite of cultivated Piaractus mesopotamicus (Osteichthyes, Characidae) in Brazil. Efficacy and hematology

The present work evaluated the efficacy of mebendazole (MBZ) treatment against infections with the monogenean helminths Anacanthorus penilabiatus, gill parasites of young cultivated pacu, Piaractus mesopotamicus. A short-term bath treatment using 100, 200 and 500 mg MBZ/1 of water for 10 and 30 min and a long-term bath using 1, 10 and 100 mg MBZ/1 of water for 24 h were utilized. Seven days after, fish were sacrificed and parasites counted. Concentrations of 500 and 200 mg MBZ/1 for 10 and 30 min showed reduced efficacy (0.0 and 0.7%) and (14.2 and 11.0%), respectively. Nevertheless, 100 mg MBZ/1 (10 min) and 10 mg MBZ/1 (24 h) showed better efficacy (79.6 and 81.4%, respectively). Treatments for 24 h provoked increases in hematocrit, hemoglobin concentration and leukocyte number when compared to those untreated fish. Mebendazole treatments also provoked alterations in the defense blood cells especially in lymphocyte and thrombocyte numbers, when the fishes were submitted to 10 and 30 min baths.