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Search Results: 1 - 10 of 177025 matches for " Ricardo B;Carvalho "
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Compact, Frequency Reconfigurable, Printed Monopole Antenna
Ricardo Gon?alves,Pedro Pinho,Nuno B. Carvalho
International Journal of Antennas and Propagation , 2012, DOI: 10.1155/2012/602780
Abstract: This paper proposes a possible implementation of a compact printed monopole antenna, useful to operate in UMTS and WLAN bands. In order to accomplish that, a miniaturization technique based on the application of chip inductors is used in conjunction with frequency reconfiguration capability. The chip inductors change the impedance response of the monopole, allowing to reduce the resonant frequency. In order to be able to operate the antenna in these two different frequencies, an antenna reconfiguration technique based on PIN diodes is applied. This procedure allows the change of the active form of the antenna leading to a shift in the resonant frequency. The prototype measurements show good agreement with the simulation results. 1. Introduction Antenna miniaturization is the result of the continuous search for smaller and compact electronic equipment that can present the same or even better performance. There are many examples of techniques used for antenna miniaturization for different applications. For printed antennas, an approach is presented in [1], where a metamaterial is used between the radiating element and the ground plane of a printed circular patch, in order to reduce its resonant frequency. Another example is presented in [2], where a Koch fractal printed monopole is used to resonate at 2.5?GHz, granting a 21% reduction in size. In [3, 4], chip inductors are used in order to reduce the resonant frequency of printed C-monopoles, without changing the size and radiation characteristics and with minor losses to the radiating efficiency and gain. This is an interesting approach, since it is quite simple to fabricate, and it is not expensive. However it leads to narrower bandwidths. Due to the growth of the wireless technologies and the appearance of new systems associated to communication devices, the development of interoperable devices is of great interest, and since the antennas are indispensable to wireless communication equipments, there is a great scientific interest for antennas capable of working in different frequency bands. To achieve this goal, multiband and UWB antennas have been proposed in literature [5]. Besides these types, another possible class of radiant structures consists of the so-called reconfigurable antennas. Reconfigurable antennas have the ability to change one or more of its radiation characteristics in real time, such as the resonant frequency, the bandwidth, the radiation pattern, or even the polarization [6]. There are different ways to achieve these changes, and different techniques have been presented, but all
Domain engineering to ensure flexibility on interaction laws of multi-agent systems
Carvalho, Gustavo R.;Paes, Rodrigo B.;Lucena, Carlos J.P.;Choren, Ricardo;
Journal of the Brazilian Computer Society , 2007, DOI: 10.1007/BF03192406
Abstract: law enforcement approaches have been proposed to promote dependability in open multi-agent systems. interaction laws are defined and then enforced to promote predictability. as new software demands and requirements appear, the system and its interaction laws must evolve to support those changes. the purpose of domain engineering is to produce a set of reusable assets for a family of systems, which are then used to build concrete members of the family. flexibility is the ease with which a system or component can be modified for use in applications other than those for which it was originally designed. in this paper, we discuss how the mlaw infrastructure was designed to support interaction law evolution providing support to produce a set of reusable laws for a family of systems. as an example, we have implemented two customizable applications in the area of electronic negotiation expressed as an open system environment.
The pathogenesis of Chagas' disease: when autoimmune and parasite-specific immune responses meet
SOARES, MILENA B. P.;PONTES-DE-CARVALHO, LAIN;RIBEIRO-DOS-SANTOS, RICARDO;
Anais da Academia Brasileira de Ciências , 2001, DOI: 10.1590/S0001-37652001000400008
Abstract: chagas' disease is a major health problem in latin america, where it constitutes one of the leading causes of heart failure. about one fourth of trypanosoma cruzi-infected individuals develop chronic chagasic cardiomyopathy (cchc), the most severe form of the disease. cchc is histologically characterized by the presence of multifocal inflammatory infiltrates in the heart, composed mainly by mononuclear cells, usually adhered to myocytes and leading to myocytolysis, and frequently by interstitial fibrosis. the pathogenesis of cchc is still unclear, despite intense investigations both in human beings and in animal models of the disease. although tissue parasitism is rare in the chronic phase of infection, an immune response targeted to persistent parasites or parasite antigens is suggested, by some authors, as the pathogenic mechanism of cchc. other researchers affirm that the lack of correlation between tissue parasitism and intensity of inflammation suggests, along with the presence of autoreactive immune responses, that cchc results from the action of an autoimmune response. herein we review reports from the literature and our own data, which together indicate, on one hand, the participation of parasite-specific immune responses and, on the other hand, clearly demonstrate the participation of heart-specific immune responses in the pathogenesis of cchc. moreover, multiple factors may determine whether an individual in the indeterminate form of the disease will develop cchc. the mechanisms by which t. cruzi breaks immunological tolerance to heart antigens are also discussed.
The pathogenesis of Chagas' disease: when autoimmune and parasite-specific immune responses meet
SOARES MILENA B. P.,PONTES-DE-CARVALHO LAIN,RIBEIRO-DOS-SANTOS RICARDO
Anais da Academia Brasileira de Ciências , 2001,
Abstract: Chagas' disease is a major health problem in Latin America, where it constitutes one of the leading causes of heart failure. About one fourth of Trypanosoma cruzi-infected individuals develop chronic chagasic cardiomyopathy (CChC), the most severe form of the disease. CChC is histologically characterized by the presence of multifocal inflammatory infiltrates in the heart, composed mainly by mononuclear cells, usually adhered to myocytes and leading to myocytolysis, and frequently by interstitial fibrosis. The pathogenesis of CChC is still unclear, despite intense investigations both in human beings and in animal models of the disease. Although tissue parasitism is rare in the chronic phase of infection, an immune response targeted to persistent parasites or parasite antigens is suggested, by some authors, as the pathogenic mechanism of CChC. Other researchers affirm that the lack of correlation between tissue parasitism and intensity of inflammation suggests, along with the presence of autoreactive immune responses, that CChC results from the action of an autoimmune response. Herein we review reports from the literature and our own data, which together indicate, on one hand, the participation of parasite-specific immune responses and, on the other hand, clearly demonstrate the participation of heart-specific immune responses in the pathogenesis of CChC. Moreover, multiple factors may determine whether an individual in the indeterminate form of the disease will develop CChC. The mechanisms by which T. cruzi breaks immunological tolerance to heart antigens are also discussed.
Detection of human papillomavirus DNA by the hybrid capture assay
Carvalho Maria Odete O.,Almeida Ricardo W.,Leite Fátima M. S.,Fellows Ilza B.
Brazilian Journal of Infectious Diseases , 2003,
Abstract: Human Papillomavirus (HPV) infection is the main cause of cervical cancers and cervical intraepithelial neoplasias (CIN) worldwide. Consequently, it would be useful to evaluate HPV testing to screen for cervical cancer. Recently developed, the second-generation Hybrid Capture (HCA II) test is a non-radioactive, relatively rapid, liquid hybridization assay designed to detect 18 HPV types, divided into high and low-risk groups. We evaluated 1055 women for HPV infection with the HCA II test. Five hundred and ten (48.3%) of these women had HPV infection; 60 (11.8%) had low cancer-risk HPV DNA; 269 (52.7%) had high-risk HPV types and 181 (35.5%) had both groups. Hence, 450 women (88.2%) in this HPV-infected group had at least one high risk HPV type, and were therefore considered to be at high risk for cancer. Among the group with Papanicolaou (Pap) test results, the overall prevalence of HPV DNA was 58.4%. Significant differences in HPV infection of the cervix were detected between Pap I (normal smears) and Pap IV (carcinomas) (p<0.0001). Values of HPV viral load obtained for Pap I and SILs were significantly different, with an upward trend (p<0.0001), suggesting a positive correlation between high viral load values and risk of SIL. Because of the high costs of the HCA II test, its use for routine cervical mass screening cannot be recommended in poor countries. Nevertheless, it is a useful tool when combined with cytology, diagnosing high-risk infections in apparently normal tissues. Use of this technique could help reduce the risk of cancer.
Resistência de popula??es de cenoura à queima-das-folhas com diferentes níveis de germoplasma tropical
Pereira, Ricardo B;Carvalho, Agnaldo Donizete F de;Pinheiro, Jadir B;Silva, Giovani O da;Vieira, Jairo V;
Horticultura Brasileira , 2012, DOI: 10.1590/S0102-05362012000300022
Abstract: leaf blight is responsible for significant losses on carrot production and the genetic resistance is one of the most efficient ways to control this disease. this study aimed to evaluate the resistance of carrot progeny populations to leaf blight with different levels of tropical germplasm. we evaluated the populations 561, 586 and 587 and, as control treatments, the commercial cultivars juliana and brs planalto. we adopted the randomized block design, with two replications and plots consisting of 1.2 m2. the disease occurred naturally on the field and was evaluated each five days, beginning at 72 days after planting date. the populations 561, 586 and 587 and cultivar brs planalto presented similar and lower severities to brasília and juliana cultivars, which did not differ from each other. there were no significant differences in commercial and total root yield. in the analyses carried out between the progenies within each population and the control no differences were observed in commercial and total yield of roots. regarding the severity, the progenies of the population 561 and 586 and brs planalto did not differ from each other and presented higher levels of resistance than brasília and juliana. however, one progeny of population 586 presented intermediate resistance. ten of 15 progenies of the population 587 presented levels of resistance similar to brs planalto, while five presented resistance similar to brasília and juliana. this increased phenotypic variability indicates potential to obtain genetic gain for resistance to leaf blight. the commercial and total root yield of the populations 561 and 586 presented negative correlation with the severity of the disease. these results indicate that resistance to leaf blight is due mainly to tropical germplasm, observed in greater quantity in the population 561, of about 87.5%.
Tamanho da amostra e método de amostragem para avalia??o de características do piment?o em estufa plástica
Lúcio, Alessandro D.;Souza, Marcelo F.;Heldwein, Arno B.;Lieberknecht, Daniel;Carpes, Ricardo H.;Carvalho, Melissa P.;
Horticultura Brasileira , 2003, DOI: 10.1590/S0102-05362003000200012
Abstract: information from all plants in a row are usually collected in greenhouse experiments. this increases experimental cost, labor, time and space for collecting data from all plants and fruits. the sample size and sampling method for sweet pepper experiments in greenhouse were determined, during winter-spring of 2000 and summer-fall of 2001. the greenhouse was located at the universidade federal de santa maria, brazil. the experiment was conducted with ten rows of 23 m length with 72 plants per row. fresh fruit weight variances were heterogeneous among rows for each cultivation season, between the two seasons. the sample sizes estimated for the winter-spring and summer-fall seasons were, respectively, 56 and 50 plants per row in each crop with 95% of confidence.
Use of MAC-ELISA for evaluation of yellow fever vaccination
Nogueira, Rita M. Ribeiro;Schatzmayr, Hermann G.;Miagostovich, Marize P.;Cavalcanti, Silvia M. B.;Carvalho, Ricardo de;
Revista do Instituto de Medicina Tropical de S?o Paulo , 1992, DOI: 10.1590/S0036-46651992000500012
Abstract: an evaluation of the igm antibody immune response against yellow fever using strain 17d was carried out by mac-elisa and prnt. the results showed an agreement of 97% between both tests and the authors conclude that mac-elisa can be used as a specific and sensitive asssay to replace the prnt for detecting yellow fever antibodies in human sera, after vaccination programs.
Propriedades mecanicas e morfologia de uma blenda polimérica de PP/HIPS compatibilizada com SEBS
Mélo Tomás J. A. de,Carvalho Laura H.,Calumby Ricardo B.,Brito Keila G. Q.
Polímeros , 2000,
Abstract: Neste trabalho o efeito da adi o de 2 a 7% em peso de um copolímero tribloco estireno-b-etileno-co-butileno-b-estireno (SEBS) em uma blenda polipropileno/poliestireno de alto impacto (PP/HIPS) 70:30 foi determinado. As propriedades em tra o e impacto, temperatura de amolecimento Vicat e morfologia da blenda PP/HIPS (70:30) em fun o da concentra o de SEBS foram determinadas. As blendas foram processadas em extrusora dupla-rosca contra-rotativa interpenetrante e as amostras moldadas por compress o. Os resultados mostraram que, embora a adi o do SEBS tenha promovido um aumento muito leve na resistência tênsil e no módulo elástico, observou-se um expressivo aumento no alongamento na ruptura e na resistência ao impacto das blendas; a temperatura Vicat das blendas foi superior à do HIPS e que a adi o do SEBS promoveu uma redu o significativa do tamanho de partícula, indicando que o SEBS exerceu um efeito emulsificante e estabilizador na morfologia das blendas investigadas. Resultados otimizados foram obtidos para a composi o contendo 5% de SEBS, o que foi atribuido à uma maior compatibilidade entre as fases.
A New Notosuchian from the Late Cretaceous of Brazil and the Phylogeny of Advanced Notosuchians
Diego Pol, Paulo M. Nascimento, Alberto B. Carvalho, Claudio Riccomini, Ricardo A. Pires-Domingues, Hussam Zaher
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0093105
Abstract: A new notosuchian crocodyliform from the Late Cretaceous Bauru Group found in the southeastern State of S?o Paulo (Brazil) is described here. The new taxon, Caipirasuchus stenognathus, is referred as a new species of the recently erected genus Caipirasuchus within the clade Sphagesauridae based on a phylogenetic analysis of basal mesoeucrocodylians. Caipirasuchus stenognathus is represented by an almost complete skull and lower jaw that has autapomorphic characters that distinguish it from other species of Sphagesauridae. These autapomorphies include: maxilla forming part of the orbital margin (absence of lacrimal-jugal contact), nasal with smooth depressions on the posterior region close to the contact with the maxilla and lacrimal, postorbital with posterior palpebral facet that extends posteriorly underneath the ear-flap groove, and a distinct anterior process of the medial flange of the retroarticular process. Additionally, the new taxon lacks autapomorphic features described in other sphagesaurids. The phylogenetic analysis results in a monophyletic genus Caipirasuchus, that is the sister group of a clade fomed by Sphagesaurus huenei, Caryonosuchus pricei, and Armadillosuchus arrudai. Sphagesaurids also include a basal clade formed by Adamantinasuchus navae and Yacarerani boliviensis. Other notosuchian taxa, such as Mariliasuchus amarali, Labidiosuchus amicum, Notosuchus terrestris, and Morrinhosuchus luziae are successive sister taxa of Sphagesauridae, forming a clade of advanced notosuchians that are restricted to the Late Cretaceous of South America. These results contrast with most previous phylogenetic hypotheses of the group that depicted some members of Sphagesauridae as more closely related to baurusuchids, or found Asian (e.g., Chimaerasuchus) or African (Malawisuchus, Pakasuchus) forms nested within advanced notosuchians that are, according to our analysis, endemic of the Late Cretaceous of South America.
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