oalib

Publish in OALib Journal

ISSN: 2333-9721

APC: Only $99

Submit

Any time

2019 ( 142 )

2018 ( 321 )

2017 ( 297 )

2016 ( 454 )

Custom range...

Search Results: 1 - 10 of 298112 matches for " Reginaldo J.; "
All listed articles are free for downloading (OA Articles)
Page 1 /298112
Display every page Item
Influence of Clad Metal Chemistry on Stress Corrosion Cracking Behaviour of Stainless Steels Claddings in Chloride Solution  [PDF]
Edmilson O. Correa, Reginaldo P. Barbosa, Augusto J. A. Buschinelli, Eduardo M. Silva
Engineering (ENG) , 2010, DOI: 10.4236/eng.2010.25051
Abstract: The effect of clad metal composition on stress corrosion cracking (SCC) behavior of three types of SMAW filler metals (E308L-16, E309-16 and E316L-16), used for cladding components subjected to highly corrosive conditions, was investigated in boiling 43% MgCl2 solution. In order to evaluate the stress corrosion cracking susceptibility of the top layer, constant load tests and metallographic examinations in tested SCC specimens were conducted. The susceptibility to stress corrosion cracking was evaluated in terms of the time-to-fracture. Results showed that the E309-16 clad metal presented the best SCC resistance. This may be attributed to the presence of a discontinuous delta-ferrite network in the austenitic matrix, which acted as a barrier to cracks propagation. Concerning to E308-16 and E316L-16 clad metals, results showed that these presented a similar SCC test performance. Their higher SCC susceptibility may be attributed to the presence of continuous vermicular delta-ferrite in their microstructure.
The effect of the nonlinearity on GCV applied to conjugate gradients in computerized tomography
Santos, Reginaldo J.;Pierro, álvaro R. de;
Computational & Applied Mathematics , 2006,
Abstract: we study the effect of the nonlinear dependence of the iterate xk of conjugate gradients method (cg) from the data b in the gcv procedure to stop the iterations. we compare two versions of using gcv to stop cg. in one version we compute the gcv function with the iterate xk depending linearly from the data b and the other one depending nonlinearly. we have tested the two versions in a large scale problem: positron emission tomography (pet). our results suggest the necessity of considering the nonlinearity for the gcv function to obtain a reasonable stopping criterion.
Osteologia craniana de Platalea ajaja (Linnaeus) (Aves, Ciconiiformes), comparada com outras espécies de Threskiornithidae
Ferreira, Carolina D.;Donatelli, Reginaldo J.;
Revista Brasileira de Zoologia , 2005, DOI: 10.1590/S0101-81752005000300003
Abstract: platalea ajaja (linnaeus, 1758) belongs to the threskiornithidae (ibises and spoonbills), threskiornitoidea, ciconiiformes. the threkiornithidae are currently divided into two groups: threskiornithinae (ibises and allies), which have curved bills used to probe into the mud, and plataleinae that have specialized flat bill shapes. the goal of the present work was to describe the cranial osteology of p. ajaja (plataleinae) and compare it with other species of the family threskiornithidae. other species pertaining to the order ciconiiformes were also considered for analyses and comparison with the former one. the results showed that p. ajaja presents many distinct characteristics from others species of the same family as: the shape of the upper jaw, dorsoventrally flattend, larger on the maxillar surface, taking a characteristic shape of a spoon; a conspicuous frontonasal suture; a short supraorbital process of the lacrimal bone; a conspicuous and sharp lateral process of the paraesphenoid bone; the nares are short with an oval shape; a short retroarticular process of the mandible; a short projection of the parasphenoid bone; a dorsoventrally flattened mandible. the characteristics shared between p. ajaja and other threskiornithidae are: frontal and lacrimal bones not fused; well developed lacrimal bone, zigomatic and paroccipital processes; occipital fonticuli present; nares located in a ridge of the premaxillar bone; reduced maxillar bone; a conspicuous and laterally flattened vomer. however, it is necessary more osteological studies with other species of the same family and a phylogenetic analysis of the group for better understanding of the relationships among the threskiornithidae.
Análise filogenética e implica??es sistemáticas e evolutivas nos Cuculiformes (Aves) com base na osteologia, comportamento e ecologia
Posso, Sérgio R.;Donatelli, Reginaldo J.;
Revista Brasileira de Zoologia , 2006, DOI: 10.1590/S0101-81752006000300003
Abstract: despite of many recent cladistic studies the classification of the order cuculiformes is still controversial. thus, we performed the most extensive cladistic analysis of the cuckoos, inferred based on 250 characters of the osteology, behavior and ecology. the resulting analysis provided 18 equally parsimonious trees (768 steps, ci = 0.4779, ri = 0.8080 and cri = 0.3861). according to the topology of the strict consensus cladogram: a) the monophyly of cuculiformes order is corroborated; b) the order is divided in two groups: a) coua/carpococcyx and b) others cuckoos (neomorphidae, (crotophagidae, (tapera/dromoccoccyx, (cuculidae))), being the systematic position of centropus ambiguous between these two groups; c) the terrestrial cuckoos are considered basal and a paraphyletic group and the arboreal cuckoos are derived and monophyletic; d) brood parasitism evolved twice in the cuckoos (in tapera/dromoccoccyx and in cuculidae).
Biogeography on the early distribution of cuckoos (Aves: Cuculiformes)
Posso, Sérgio R.;Donatelli, Reginaldo J.;
Zoologia (Curitiba) , 2012, DOI: 10.1590/S1984-46702012000300001
Abstract: cuckoos are widely distributed, but are concentrated in the tropics, where they occupy a wide range of habitats. both terrestrial and arboreal behaviors can be found in this group, but there is no consensus on as to whether these behaviors have arisen more than once. moreover, the historical distribution of cuckoos is poorly understood. this paper presents a biogeographyc analysis of the early history of the distribution of these birds. the analysis was performed by using the principle of parsimony based on primary and secondary "brooks parsimony analysis" (bpa). despite some exceptions, the primary bpa corroborated events of vicariance (general pattern) in the early distribution of cuckoos and a terrestrial ancestor widespread in the gondwana. the most parsimonious hypothesis suggests that the distribution of terrestrial cuckoos (basal group) is associated with the break-up of the gondwana (early to mid cretaceous), consistent with molecular data for other living birds. on the other hand, the fossil records indicate a more recent origin (paleocene to upper tertiary) in the laurasia. nevertheless, to corroborate the fossil records, the early distribution of cuckoos would not be explained by parsimony, since additional steps on dispersion and local extinctions should be added. in addition, according to the secondary bpa, most exceptions can be explained by dispersion as the origin of the arboreal cuckoos (derived group) in south america, where they dispersed to other continents.
Comportamento do comprimento do colo uterino em gesta es normais avaliado pela ultra-sonografia transvaginal
Freitas Júnior Reginaldo Antonio de Oliveira
Revista Brasileira de Ginecologia e Obstetrícia , 2002,
Abstract:
The effect of the nonlinearity on GCV applied to conjugate gradients in computerized tomography
Reginaldo J. Santos,álvaro R. de Pierro
Computational and Applied Mathematics , 2006,
Abstract: We study the effect of the nonlinear dependence of the iterate x k of Conjugate Gradients method (CG) from the data b in the GCV procedure to stop the iterations. We compare two versions of using GCV to stop CG. In one version we compute the GCV function with the iterate x k depending linearly from the data b and the other one depending nonlinearly. We have tested the two versions in a large scale problem: positron emission tomography (PET). Our results suggest the necessity of considering the nonlinearity for the GCV function to obtain a reasonable stopping criterion.
Popula??es indígenas e lógicas tradicionais de Desenvolvimento Local
Brand, Antonio J.;Colman, Rosa S.;Costa, Reginaldo B.;
Intera??es (Campo Grande) , 2008, DOI: 10.1590/S1518-70122008000200006
Abstract: the text analyses the prospects for indigenous populations development, having as a reference the kaiowá and guarani, in south mato grosso, brazil. although they have the same demands for protection, food supply and health care amongst other requirements, and very often, with the same economic situation or natural resources available, their historically constructed ways of satisfying the necessities of each group have been specific, this being the distinctness of each group that goes back to their social organization, world visions and specific cosmologies.
Leishmania (Viannia) lainsoni (Kinetoplastida: Trypanosomatidae), a divergent Leishmania of the Viannia subgenus: a mini review
Corrêa, José R;Brazil, Reginaldo P;Soares, Maurilio J;
Memórias do Instituto Oswaldo Cruz , 2005, DOI: 10.1590/S0074-02762005000600014
Abstract: leishmania (viannia) lainsoni is the leishmania species that presents the most distinct biological (morphology, growth in axenic culture medium), biochemical (enzymatic electrophoresis profile), and molecular biology characteristics, when compared to other species of the viannia subgenus. development of promastigote forms of this parasite attached to the wall of the pyloric and hind gut regions of sand fly vectors is a solid characteristic that allows its positioning in the viannia subgenus. however, taxonomic data from biochemical and molecular techniques on this leishmania species are still not conclusive. it is evident the difficulty in taxonomically positioning this borderline leishmania species. in this review we present the data accumulated since l. (viannia) lainsoni has been described and we discuss its position in the viannia subgenus.
Osteologia craniana de Coraciiformes (Aves)
Pascotto, Márcia C.;H?fling, Elizabeth;Donatelli, Reginaldo J.;
Revista Brasileira de Zoologia , 2006, DOI: 10.1590/S0101-81752006000300032
Abstract: the families alcedinidae (kingfishers), momotidae (motmots), todidae (todies), meropidae (bee-eaters), coraciidae (rollers), brachypteraciidae (ground-rollers), leptosomidae (cuckoo-rollers), phoeniculidae (woodhoopoes), upupidae (hoopoes) and bucerotidae (hornbills) are traditionally grouped in the order coraciiformes, but no external morphological character is commom to the whole order. a comparative study of the cranial osteology of the coraciiformes seeks to find characters capable to diagnose the order or groups of taxa, serving yet as a source to provide characters for future phylogenetic analysis. as established by the external morphological data, the cranial osteology has ratified the broad morphological divergence among the coraciiformes taxa. only two characters are common to the order as a whole, as the presence of the laterosphenoid fossa and the absence of the suprameatic process, but these characters are not exclusive of the order. primary homologies were found, showing similarities among several families, such as: the craniofacial flexion zone is an indefinite region in adults of the coraciidae, leptosomidae, phoeniculidae, upupidae and bucerotidae; the temporal fossa has intermediate development and deepy in the momotidae, meropidae, coraciidae, brachypteraciidae and bucerotidae; the lacrimal bone is absent in the momotidae, fused with the ectethmoid in adults of the upupidae, phoeniculidae and bucerotidae, and present and free in the alcedinidae, todidae, meropidae, coraciidae, brachypteraciidae and leptosomidae; and the o retroarticular process of the mandible is developed in the upupidae, phoeniculidae and bucerotidae.
Page 1 /298112
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.