Microscopic generalization of the standard interacting boson model Hamiltonian in the restricted dynamics approach

The evaluation of the microscopic generalized interacting boson model (GIBM) Hamiltonian, deduced from the general microscopic nuclear Hamiltonian via the collective O-A-1 invariant microscopic Hamiltonian of the general restricted dynamics model (RDM) in the case of central multipole and multipole-Gauss type effective NN-potential is briefly discussed. The GIBM version, which includes all sixth-order terms in the expansion of the collective part of the NN-potential, has been obtained. This GIBM Hamiltonian contains additional terms compared with the standard (sd-boson) interacting boson model (IBM). The microscopic expressions for the standard IBM Hamiltonian parameters in terms of the employed effective NN-potential parameters have also been obtained.

Acute phase proteins: a potential approach for diagnosing chronic infection by Trypanosoma vivax

O objetivo do presente estudo foi verificar possíveis alterações nas proteínas de fase aguda em ovinos infectados experimentalmente com Trypanosoma vivax. Para tanto, foram utilizados oito ovinos machos, sendo quatro usados como controle e quatro infectados com 10(5) tripomastigotas de T. vivax. Colheram-se amostras de sangue em dois tempos antes da infecção e, posteriormente, aos 5, 7, 9, 11, 13, 15, 20, 30, 45, 60, 75, 90, 105 e 120 dias após a infecção (dpi); após centrifugação e aliquotização das amostras. As proteínas de fase aguda foram separadas por eletroforese em gel de acrilamida, contendo dodecil sulfato de sódio, e suas concentrações foram determinadas através de densitometria computadorizada. A dosagem de proteína total foi realizada pelo método colorimétrico do biureto. A contagem dos tripanossomas foi realizada diariamente, utilizando-se uma alíquota de 5 µL de sangue disperso em lâmina de microscopia, sob lamínula de 22 × 22 mm, contando-se os parasitos em 100 campos microscópicos, com objetiva de 40×, multiplicados pelo fator de correção do microscópio, e o resultado expresso em parasitos por mL de sangue. Para a análise estatística, empregou-se o teste de Wilcoxon a 5% de probabilidade. Foi observada a diminuição de diversas proteínas de fase aguda e aumento de antitripsina e transferrina que podem ser utilizadas para auxiliar no diagnóstico da infecção por T. vivax, principalmente na fase crônica da infecção.

Microscopic evidence supports the hypothesis of high cellulose degradation capacity by the symbiotic fungus of leaf-cutting ants

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Occurrence and significance of ovarian and follicular regression in cachara Pseudoplatystoma fasciatum (Linnaeus, 1766): a histology approach

Estudaram-se os processos de regressão ovariana e atresia folicular em cachara, Pseudoplatystoma fasciatum, mantida em cativeiro, na reprodução não induzida por hormônios. As características macro e microscópicas (diâmetro dos ovócitos e histologia) dos ovários foram descritas a cada 20 dias, em quatro estádios: na regressão inicial (Rg I - os primeiros 20 dias), na regressão intermediária (Rg II - do 21º ao 40º dia), na regressão final (Rg III - do 41º ao 80º dia) e na fase de recuperação ou de repouso II (R II - do 81º ao 150º dia). O experimento foi realizado do final de janeiro (verão-dias longos) a maio (outono-dias curtos). No início do experimento, as amostras apresentaram ovócitos com diâmetros que variaram de 437,5 a 1.187,5mm, sugerindo encontrarem-se nas fases perinucleolar, de maturação final e atrésicos. Aos 150 dias, os diâmetros atingiram os menores valores e pôde-se visualizar a zona radiata rompida e o vitelo reabsorvido. Concomitantemente, houve diminuição abrupta dos valores médios do índice gonadossomático, da temperatura da água, das horas de luz e de chuva. A involução gradual do longo processo foi dinâmica e complexa, afetando o êxito da desova (taxas de fertilização, de eclosão e de sobrevivência de larvas) e, conseqüentemente, o sistema produtivo.

Second quantization approach to composite hadron interactions in quark models

Starting from the Fock space representation of hadron bound states in a quark model, a change of representation is implemented by a unitary transformation such that the composite hadrons are redescribed by elementary-particle field operators. Application of the unitary transformation to the microscopic quark Hamiltonian gives rise to effective hadron-hadron, hadron-quark, and quark-quark Hamiltonians. An effective baryon Hamiltonian is derived using a simple quark model. The baryon Hamiltonian is free of the post-prior discrepancy which usually plagues composite-particle effective interactions.

Field-theoretic approach for systems of composite hadrons

Systems containing simultaneously hadrons and their constituents are most easily described by treating composite hadron field operators on the same kinematical footing as the constituent ones. Introduction of a unitary transformation allows redescription of hadrons by elementary-particle field operators. Transformation of the microscopic Hamiltonian leads to effective Hamiltonians describing all possible processes involving hadrons and their constituents.

A computer vision approach to quantify leaf anatomical plasticity: A case study on gochnatia polymorpha (less.) cabrera

Inferences about leaf anatomical characteristics had largely been made by manually measuring diverse leaf regions, such as cuticle, epidermis and parenchyma to evaluate differences caused by environmental variables. Here we tested an approach for data acquisition and analysis in ecological quantitative leaf anatomy studies based on computer vision and pattern recognition methods. A case study was conducted on Gochnatia polymorpha (Less.) Cabrera (Asteraceae), a Neotropical savanna tree species that has high phenotypic plasticity. We obtained digital images of cross-sections of its leaves developed under different light conditions (sun vs. shade), different seasons (dry vs. wet) and in different soil types (oxysoil vs. hydromorphic soil), and analyzed several visual attributes, such as color, texture and tissues thickness in a perpendicular plane from microscopic images. The experimental results demonstrated that computational analysis is capable of distinguishing anatomical alterations in microscope images obtained from individuals growing in different environmental conditions. The methods presented here offer an alternative way to determine leaf anatomical differences. © 2013 Elsevier B.V.

Immunohistochemical approach to the pathogenesis of clinical cases of bovine Herpesvirus type 5 infections

Meningoencephalitis by Herpesvirus type 5 (BoHV-5) in cattle has some features that are similar to those of herpetic encephalitis in humans and other animal species. Human Herpesvirus 3 (commonly known as Varicella-zoster virus 1), herpes simplex viruses (HSV), and equid Herpesvirus 1 (EHV-1) induce an intense inflammatory, vascular and cellular response. In spite of the many reports describing the histological lesions associated with natural and experimental infections, the immunopathological mechanisms for the development of neurological disorder have not been established. A total of twenty calf brains were selected from the Veterinary School, University of São Paulo State, Araçatuba, Brazil, after confirmation of BoHV-5 infection by virus isolation as well as by a molecular approach. The first part of the study characterized the microscopic lesions associated with the brain areas in the central nervous system (CNS) that tested positive in a viral US9 gene hybridization assay. The frontal cortex (Fc), parietal cortex (Pc), thalamus (T) and mesencephalon (M) were studied. Secondly, distinct pathogenesis mechanisms that take place in acute cases were investigated by an immunohistochemistry assay. This study found the frontal cortex to be the main region where intense oxidative stress phenomena (AOP-1) and synaptic protein expression (SNAP-25) were closely related to inflammatory cuffs, satellitosis and gliosis, which represent the most frequently observed neurological lesions. Moreover, MMP-9 expression was shown to be localized in the leptomeninges, in the parenchyma and around mononuclear infiltrates (p < 0.0001). These data open a new perspective in understanding the role of the AOP-1, MMP-9 and SNAP-25 proteins in mediating BoHV-5 pathogenesis and the strategies of host-virus interaction in order to invade the CNS.