Showing papers by "Federal University of Roraima published in 2008"
TL;DR: This report describes and discusses the annotation of 15,387 ESTs from guarana seeded-fruits, highlighting sequences from the flavonoid and purine alkaloid pathways, and those related to biotic stress avoidance, which is the largest set of sequences registered for the Sapindaceae family.
Abstract: Guarana (Paullinia cupana var. sorbilis) is a plant native to the central Amazon basin. Roasted seed extracts have been used as medicinal beverages since pre-Colombian times, due to their reputation as stimulants, aphrodisiacs, tonics, as well as protectors of the gastrointestinal tract. Guarana plants are commercially cultivated exclusively in Brazil to supply the national carbonated soft-drink industry and natural product stores around the world. In this report, we describe and discuss the annotation of 15,387 ESTs from guarana seeded-fruits, highlighting sequences from the flavonoid and purine alkaloid pathways, and those related to biotic stress avoidance. This is the largest set of sequences registered for the Sapindaceae family.
56 citations
TL;DR: O coeficiente de deteccao nessa faixa etaria manteve-se no nivel hiperendemico entre 1998 e 2003, reduzindo a partir do ano de 2004 mas mantendo endemicidade muito alta.
Abstract: OBJETIVO: Analisar a situacao epidemiologica da hanseniase em criancas, em zona urbana. METODOS: Foram estudados 474 casos de hanseniase, em menores de 15 anos, detectados na zona urbana de Manaus (AM), de 1998 a 2005. A partir dos dados do Sistema de Informacoes de Agravos de Notificacao foram analisados o perfil da endemia e a qualidade do atendimento nos servicos de saude, utilizando os indicadores epidemiologicos e operacionais Programa Nacional de Eliminacao da Hanseniase. RESULTADOS: Os casos de hanseniase em menores de 15 anos corresponderam a 10,4% do total de casos detectados no periodo. O coeficiente de deteccao nessa faixa etaria manteve-se no nivel hiperendemico entre 1998 e 2003, reduzindo a partir do ano de 2004 mas mantendo endemicidade muito alta. A forma clinica mais frequente foi a tuberculoide, seguida da dimorfa. As formas paucibacilares corresponderam a 70,7% dos casos e no momento do diagnostico, o grau de incapacidades foi avaliado em 94,7% dos pacientes, dos quais 2,9% apresentaram incapacidades fisicas. A maioria dos casos (99,4%) foi tratada com o esquema poliquimioterapico da Organizacao Mundial da Saude. CONCLUSOES: Apesar de seu decrescimo, o coeficiente de deteccao da hanseniase nas criancas em Manaus mantem nivel de endemicidade muito alto.
45 citations
TL;DR: In this paper, the presence of dengue virus in larval forms of Aedes aegypti and associated vector presence with rainfall and incidence of disease was detected by using trap positivity rate and egg density.
Abstract: OBJECTIVE: To detect the presence of dengue virus in larval forms of Aedes aegypti and to associate vector presence with rainfall and incidence of disease. METHODS: Eighteen households were randomly selected for egg collection in a neighborhood of the city of Boa Vista, Roraima, in Northern Brazil. Two oviposition traps were installed per home, and removed after one week. This was repeated on a monthly basis between November 2006 and May 2007. Trap positivity rate and egg density were calculated. Following the eclosion of 1,422 eggs, 44 pools of at least 30 larvae each were formed, which were evaluated for presence of dengue virus using RT-PCR and hemi-nested PCR. Dengue incidence rates in the period were correlated with rainfall rates. The association between these two variables and the number of eggs collected was determined using Pearson correlation. RESULTS: None of the pools tested positive for presence of dengue virus, despite the high incidence of dengue in the neighborhood during the studied period. The density of Ae. aegypti increased with rainfall, but was not correlated with incidence of dengue. CONCLUSIONS: The results suggest that transovarial transmission of dengue virus in mosquitoes occurs at a very low frequency, and therefore virus persistence in urban settings may not depend on such transmission. The mosquito population increased during the rainy season due to increased formation of breeding sites; the lack of correlation with incidence of dengue may be due to underestimation of incidence data during epidemics.
31 citations
TL;DR: In this paper, the authors investigated the 5D Brans-Dicke theory of gravity in the context of macroscopic matter configurations generated from pure vacuum in five dimensions, an approach first proposed by Wesson and collaborators in the framework of 5D general relativity.
Abstract: We investigate, in the context of five-dimensional (5D) Brans–Dicke theory of gravity, the idea that macroscopic matter configurations can be generated from pure vacuum in five dimensions, an approach first proposed by Wesson and collaborators in the framework of 5D general relativity. We show that the 5D Brans–Dicke vacuum equations when reduced to four dimensions (4D) lead to a modified version of Brans–Dicke theory in 4D. As an application of the formalism, we obtain two 5D extensions of 4D O’Hanlon and Tupper vacuum solution and show that they lead two different cosmological scenarios in 4D.
29 citations
TL;DR: In this article, the authors considered two-dimensional infinite circular quantum wells (CQWs) and circular quantum dots with position-dependent mass (PDM) envisaging a possible experimental realization.
28 citations
TL;DR: In this article, analisar a situacao epidemiologica da Hanseniase in criancas, em a zona urbana de Manaus, Brazil, from 1998 to 2005.
Abstract: OBJETIVO: Analisar a situacao epidemiologica da hanseniase em criancas, em zona urbana. METODOS: Foram estudados 474 casos de hanseniase, em menores de 15 anos, detectados na zona urbana de Manaus (AM), de 1998 a 2005. A partir dos dados do Sistema de Informacoes de Agravos de Notificacao foram analisados o perfil da endemia e a qualidade do atendimento nos servicos de saude, utilizando os indicadores epidemiologicos e operacionais Programa Nacional de Eliminacao da Hanseniase. RESULTADOS: Os casos de hanseniase em menores de 15 anos corresponderam a 10,4% do total de casos detectados no periodo. O coeficiente de deteccao nessa faixa etaria manteve-se no nivel hiperendemico entre 1998 e 2003, reduzindo a partir do ano de 2004 mas mantendo endemicidade muito alta. A forma clinica mais frequente foi a tuberculoide, seguida da dimorfa. As formas paucibacilares corresponderam a 70,7% dos casos e no momento do diagnostico, o grau de incapacidades foi avaliado em 94,7% dos pacientes, dos quais 2,9% apresentaram incapacidades fisicas. A maioria dos casos (99,4%) foi tratada com o esquema poliquimioterapico da Organizacao Mundial da Saude. CONCLUSOES: Apesar de seu decrescimo, o coeficiente de deteccao da hanseniase nas criancas em Manaus mantem nivel de endemicidade muito alto.
28 citations
TL;DR: In this paper, the presence of dengue virus in larval forms of Aedes aegypti and associated vector presence with rainfall and incidence of disease was detected by using trap positivity rate and egg density.
Abstract: OBJECTIVE: To detect the presence of dengue virus in larval forms of Aedes aegypti and to associate vector presence with rainfall and incidence of disease. METHODS: Eighteen households were randomly selected for egg collection in a neighborhood of the city of Boa Vista, Roraima, in Northern Brazil. Two oviposition traps were installed per home, and removed after one week. This was repeated on a monthly basis between November 2006 and May 2007. Trap positivity rate and egg density were calculated. Following the eclosion of 1,422 eggs, 44 pools of at least 30 larvae each were formed, which were evaluated for presence of dengue virus using RT-PCR and hemi-nested PCR. Dengue incidence rates in the period were correlated with rainfall rates. The association between these two variables and the number of eggs collected was determined using Pearson correlation. RESULTS: None of the pools tested positive for presence of dengue virus, despite the high incidence of dengue in the neighborhood during the studied period. The density of Ae. aegypti increased with rainfall, but was not correlated with incidence of dengue. CONCLUSIONS: The results suggest that transovarial transmission of dengue virus in mosquitoes occurs at a very low frequency, and therefore virus persistence in urban settings may not depend on such transmission. The mosquito population increased during the rainy season due to increased formation of breeding sites; the lack of correlation with incidence of dengue may be due to underestimation of incidence data during epidemics.
24 citations
TL;DR: Seedling morphology data provide relevant systematic characters that support the proposed changes in the generic delimitation of Acosmium, and are evaluated to evaluate the systematic value of these characters.
Abstract: Morphological and taxonomic studies have proposed changing the circumscription of Acosmium, with the recognition of two additional genera, Leptolobium and Guianodendron. A study on seedling morphology of all accepted species of Acosmium s.str., five species of Leptolobium, and Guianodendron praeclarum is presented, aiming to evaluate the systematic value of these characters. Guianodendron has crypto-hypogeal reserve seedlings, while Acosmium and Leptolobium have phanero-epigeal seedlings with foliaceous cotyledons. The latter two genera are distinguishable from each other mainly by hypocotyl shape, ratio of hypocotyl length to epicotyl length, nyctinasty of leaflets and cotyledons, shape and venation of cotyledons, stipule and leaflet morphology, presence or absence of intercotyledonary glands, and presence of glands on other vegetative parts. In conclusion, seedling morphology data provide relevant systematic characters that support the proposed changes in the generic delimitation of Acosmium.
22 citations
TL;DR: This work describes the studies of isolation of the chemical constituents and antiedematogenic activity of the species Peltodon radicans (Lamiaceae), which is used in the treatment of snakebites and scorpion stings in the region.
Abstract: Most of the snakebite incidents in the Amazon region involve Bothrops atrox, whose venom presents the most potent edematogenic and necrotic activities in the genus. This work describes the studies of isolation of the chemical constituents and antiedematogenic activity of the species Peltodon radicans (Lamiaceae), which is used in the treatment of snakebites and scorpion stings in the region. The extracts presented aliphatic hydrocarbons, 3b-OH,b-amirin (1), 3b-OH,a-amirin (2), b-sitosterol (3), stigmasterol (4), ursolic acid (5), 2a,3b,19a-trihydroxy-urs-12-en-28-oic acid (tormentic acid, 6), methyl 3b-hydroxy,28-methyl-ursolate (7), sitosterol-3-O-b-D-glucopyranoside (8), and stigmasterol-3-O-b-D-glucopyranoside (9). The flower extracts presented the higher antiedematogenic activity. This is the first report on the study of the flowers, stem, and roots of this plant.
21 citations
TL;DR: Aedes albopictus is registered for the first time in Roraima, Brazil, and its occurrence could favor a linkage between urban and forest cycles of yellow fever and other arboviruses in Brazil.
Abstract: Aedes albopictus is registered for the first time in Roraima, Brazil. From June 2006 to May 2007, three pupae and ten larvae of Ae. albopictus were collected, during routine surveillance work in three urban neighborhoods in the city of Boa Vista. Two larvae reached adulthood as females. Although Ae. albopictus is not presently considered of primary importance in dengue transmission, its occurrence could favor a linkage between urban and forest cycles of yellow fever and other arboviruses in Brazil.
17 citations
TL;DR: A profilaxia medicamentosa da trombose venosa profunda e subutilizada em pacientes com indicacao para recebe-la, tornando necessaria a implementacao de um programa de educacao continuada sobre o tema.
Abstract: CONTEXTO: Trabalho realizado na area de cirurgia vascular, porem relevante a todas as especialidades clinicas e cirurgicas devido a importância clinica da trombose venosa profunda e sua principal complicacao, a embolia pulmonar. OBJETIVOS: Verificar se a profilaxia para a trombose venosa profunda esta sendo utilizada de forma adequada e rotineira em nosso servico e avaliar o conhecimento dos medicos sobre as indicacoes de profilaxia medicamentosa. METODOS: Foi realizado um estudo prospectivo com 850 pacientes internados de marco a maio de 2007 no Hospital Geral de Roraima. Foram pesquisados fatores clinicos, medicamentosos e cirurgicos. A estratificacao de risco e a avaliacao da profilaxia foram estabelecidas conforme a classificacao recomendada pela Sociedade Brasileira de Angiologia e Cirurgia Vascular e o protocolo realizado por Caiafa em 2002. Os medicos responderam a um questionario e analisaram tres casos clinicos hipoteticos. Os dados foram tabulados e analisados estatisticamente usando o programa de computador Epi-Info 2002®. RESULTADOS: Dos 850 pacientes estudados, 557 (66,66%) eram clinicos e 293 (33,34%) cirurgicos. Do total, 353 pacientes (41,56%) foram classificados como baixo risco, 411 (48,32%) como medio risco e 86 (10,12%) como alto risco para desenvolver trombose venosa profunda. Dos 497 pacientes que necessitavam receber profilaxia medicamentosa para trombose venosa profunda, apenas 120 (24%) a receberam; destes, 102 (85%) a receberam de forma correta. Dos que nao necessitavam de profilaxia, nenhum a recebeu. Os clinicos prescreveram mais e de forma mais correta a profilaxia em relacao aos cirurgioes, apesar de estes terem demonstrado possuir um melhor conhecimento teorico do tema. No geral, o conhecimento teorico sobre trombose venosa profunda foi insuficiente. CONCLUSOES: Em nosso servico, a profilaxia medicamentosa da trombose venosa profunda e subutilizada em pacientes com indicacao para recebe-la, tornando necessaria a implementacao de um programa de educacao continuada sobre o tema.
TL;DR: Five new combinations are made, five new synonyms are recognized, lectotypes of five species names are designated, and two names, hitherto assigned to Acosmium, are excluded from both that genus and Leptolobium.
Abstract: Morphological studies of Acosmium Schott indicate that the majority of species currently included in the genus should be transferred to Leptolobium Vogel. This paper presents a nomenclatural treatment reflecting reinstatement of the name Leptolobium. Five new combinations are made, five new synonyms are recognized, lectotypes of five species names are designated, and two names, hitherto assigned to Acosmium, are excluded from both that genus and Leptolobium.
TL;DR: The inoculation by spraying on covering increased nodulation and plant dry matter in the 45 and 60 DAE and increased significantly grain yield and N content, similarly to N fertilization treatment, and was superior to the control, and inferior to the standard inoculation related to grain yield.
Abstract: The objective of this work was to evaluate a Bradyrhizobium inoculation method on soybean by spraying inoculant over plants. An experiment was conducted in the Cerrado of Roraima. Treatments tested were: control without inoculation; standard inoculation method with two doses of inoculant per hectare applied on seeds; inoculation with threefold standard inoculation dose applied 18 days after plants emergence (DAE); fertilization with 200 kg ha-1 of nitrogen, without inoculation. The inoculation by spraying on covering increased nodulation and plant dry matter in the 45 and 60 DAE. It also increased significantly grain yield and N content, similarly to N fertilization treatment, and was superior to the control, and inferior to the standard inoculation related to grain yield.
TL;DR: The aim of this study was to establish an effective and satisfactory method to control chilling injuries on Tahiti lime, and the fruits that were harvested in Boa Vista, RR, 140 and 150 days after flowering, showed average values of 7.9 and 8.2oBrix, which did not provide any significative effect.
Abstract: O estudo objetivou o estabelecimento de um metodo efetivo e satisfatorio do controle do dano de frio em limas-acidas. Os frutos colhidos no municipio de Boa Vista-RR, 140 e 150 dias apos a floracao, apresentaram valores medios de 7,9 e 8,2 oBrix; 6,3 e 6,0 mL de acido citrico.100mL de polpa-1 e pH de 2,8 e 3,0, respectivamente, nas duas colheitas. Apos cada colheita, os frutos foram levados ao laboratorio de Fitotecnia/UFRR, onde foram selecionados, limpos e submetidos aos tratamentos: T1 - controle; T2, T3 e T4 - condicionamento a 35oC, por 6, 12 e 24 horas, respectivamente; T5 - aquecimento intermitente a 20oC, por 8 horas, apos 5 e 10 dias a 1oC; T6 - aquecimento intermitente a 20oC, por 8 horas, apos 10 e 20 dias a 1oC; T7 - ethephon a 1.500 mg.L-1; T8 - ethephon a 3.000 mg.L-1. Os tratamentos T9 ao T16, diferenciaram-se dos tratamentos T1 a T8, apenas, na data da colheita (10 dias apos a primeira). O experimento foi avaliado a cada 15 dias, durante 75 dias, a 1 ± 0,5 oC e 92 ± 5 % de UR, quanto ao dano de frio, aspecto visual, perda de massa fresca, solidos soluveis (SS), acidez titulavel (AT), SS/AT (ratio - RT), clorofila total e acido ascorbico. O atraso na colheita nao proporcionou efeito significativo algum. Todos os tratamentos, a excecao do controle e do aquecimento intermitente aos 10 e 20 dias, foram eficientes no controle do dano de frio. No entanto, o tratamento quimico e o condicionamento termico aceleraram precocemente o metabolismo dos frutos, principalmente no que concerne a perda de massa fresca e ao aspecto visual. O maior teor de clorofila total e de acido ascorbico, bem como o melhor aspecto visual, a nao-incidencia de podridoes e a menor perda de massa fresca foram detectadas nos frutos submetidos ao aquecimento intermitente aos 5 e 10 dias. Os SS, AT e RT estavam dentro dos padroes de qualidade e nao variaram estatisticamente entre os tratamentos.
TL;DR: In vitro virulence of Metarhizium anisopliae and Beauveria bassiana to eggs and adults of C. felis felis is verified and indicates that these entomopathogenic fungi have promising potential for use in controlling both Ctenocephalides felis egg and adult stages.
Abstract: Ctenocephalides felis felis is a flea species that parasitizes dogs and cats. The current study verified the in vitro virulence of the entomopathogenic fungi Metarhizium anisopliae and Beauveria bassiana to eggs and adults of C. felis felis. The fungal isolates were cultivated on rice grains in plastic bags. Conidial suspensions were then prepared by immersing the grains in Tween 80 aqueous solution (0.01%). Eggs and adults of C. felis felis were obtained from a laboratory colony. Experiments were composed of one control and four treatment groups (10(5), 10(6), 10(7), and 10(8) conidia mL(-1)). Both insect pathogens inhibited egg hatchability and caused adult mortality. Among isolates used in this study, M. anisopliae (isolate E9) was the most successful at inhibiting hatching, while B. bassiana (isolate 986) was the most powerful for causing mortality in adults. The results indicate that these entomopathogenic fungi have promising potential for use in controlling both C. felis felis egg and adult stages.
TL;DR: The authors revisaran estudios sobre the influence of emociones on the funcionamiento of the memoria and, in particular, the production of falsos recuerdos.
Abstract: En este articulo se revisaran los estudios sobre la influencia de las emociones sobre el funcionamiento de la memoria y, en particular, la produccion de falsos recuerdos. Los falsos recuerdos son un tipo de distorsion, que son la memoria acerca de acontecimientos que nunca se produjieron. Las emociones son descritas por las dimensiones de valencia y excitacion. Numerosos estudios han sugerido que la valencia y alerta pueden beneficiar la memoria por distintos procesos cognitivos y mecanismos neuronales. Ya la investigacion sobre la influencia de las emociones en la produccion de falsos recuerdos es todavia incipiente, y difiere en sus resultados. El objetivo principal del presente articulo sera el debate metodologico de la investigacion que relaciona las emociones con los falsos reconocimientos, y las explicaciones teoricas que se han producido para dar cuenta de este fenomeno. Por ultimo, presentamos algunas sugerencias para futuros estudios, y el estado actual de la investigacion desarrollada en Brasil acerca de esta tematica.
TL;DR: In this paper, the authors compared Brody, Von Bertalanffy, Gompertz, France, Logistic, Modified logistic and Dual-pool logistic models for cumulative gas production curve in sunflower and corn silages.
Abstract: The aim of this work was to identify among the Brody, Von Bertalanffy, Gompertz, France, Logistic, Modified logistic and Dual-pool logistic models, the one that presents the highest quality of fit for cumulative gas production curve in sunflower and corn silages. The quality of fit was evaluated by coefficient of determination, residual mean square, graphic analysis of the observed and estimated curves, graphic analysis of dispersion of the studentized residual, average percentage error, relative efficiency and number of iteractions to converge. Brody, France and Dual-pool logistic models showed the largest values of coefficient of determination in both substrates, and the difference among them was considered worthless. They also showed the smallest values of residual mean square in sunflower silages, being the difference among them considered worthless. Brody and France models presented smaller residual mean square in corn silages. All the models showed positive dispersion of the residual in both substrates after 144 hours of incubation. The Brody model showed smaller average percentage error and number of iterations in both substrates. The Dual-pool logistic and France models showed higher relative efficiency, respectively, in sunflower and corn silages. Thus, the Dual-pool logistic model showed higher quality of fit to the gas production curve in sunflower and corn silages.
TL;DR: In this article, the authors synthesized and characterized the complexes [Eu(eta)2·(H2O)4]Cl and [Enu(eta), 2·phen)·(h2O), 4,4,4-trifluoroacetoacetate; phen = 1,10-phenanthroline.
TL;DR: In this article, the synthesis and characterization of MoO3 intercalation compounds with pyridazine (pdz), acrylamid (ald) and tris(hydroxymethyl)aminomethane (tham) is reported, taking into account the possible uses of molybdenum trioxide as a molecular sieve towards nitrogen containing compounds.
Abstract: The synthesis and characterization (by CHN elemental analysis, FTIR spectroscopy, XRD diffractometry, thermogravimetry and SEM microscopy) of MoO3 intercalation compounds with pyridazine (pdz), acrylamid (ald) and tris(hydroxymethyl)aminomethane (tham) is reported. Such investigation was performed taking into account the possible uses of molybdenum trioxide as a molecular sieve towards nitrogen containing compounds. It is verified that the affinity of MoO3 towards the investigated species follows the sequence: ald ≅ tham > pdz.
TL;DR: In this paper, a phase transition of hadronic matter made of nucleons, Δ-resonances, hyperons and leptons was analyzed to determine the characteristics of a hybrid star.
Abstract: The color–flavor locked (CFL) phase is believed to be the fundamental state of strange quark matter (SQM) at high densities. The CFL phase is a color superconductor composed of pairs of u, d and s quarks, with no electrons, forming a Bose condensate. In this work, we analyze a possible phase transition of hadronic matter made of nucleons, Δ–resonances, hyperons and leptons, to CFL superconducting quark matter. An equation of state taking into account this phase transition is employed to determine the characteristics of a hybrid star. The role of the color superconducting gap on the hybrid stars properties is also discussed.
TL;DR: This article revisaran los estudios sobre la influencia of emociones sobre el funcionamiento de la memoria and, en particular, the produccion of falsos recuerdos.
Abstract: En este articulo se revisaran los estudios sobre la influencia de las emociones sobre el funcionamiento de la memoria y, en particular, la produccion de falsos recuerdos Los falsos recuerdos son un tipo de distorsion, que son la memoria acerca de acontecimientos que nunca se produjieron Las emociones son descritas por las dimensiones de valencia y excitacion Numerosos estudios han sugerido que la valencia y alerta pueden beneficiar la memoria por distintos procesos cognitivos y mecanismos neuronales Ya la investigacion sobre la influencia de las emociones en la produccion de falsos recuerdos es todavia incipiente, y difiere en sus resultados El objetivo principal del presente articulo sera el debate metodologico de la investigacion que relaciona las emociones con los falsos reconocimientos, y las explicaciones teoricas que se han producido para dar cuenta de este fenomeno Por ultimo, presentamos algunas sugerencias para futuros estudios, y el estado actual de la investigacion desarrollada en Brasil acerca de esta tematica
TL;DR: The essential oil of composition obtained from the leaves of Cunila angustifolia, collected in different seasons of the year in the southern Brazilian state of Santa Catarina, was analyzed by GC and GC/MS and the main constituent of the oil was pulegone.
Abstract: The essential oil of composition obtained from the leaves of Cunila angustifolia, collected in different seasons of the year in the southern Brazilian state of Santa Catarina, was analyzed by GC and GC/MS. Twenty-two compounds were identified and the main constituent of the oil was pulegone. This monoterpene was found in different concentrations, winter (56.5%), spring (72.3%), summer (64.1%) and autumn (56.0%).
Journal Article•
TL;DR: In this paper, the authors discuss a configuracao de um paradigma neoglobalista for a politica externa chinesa, apresenta indefinicoes estrategicas que intervem na insercao internacional do dragao oriental.
Abstract: Este artigo visa discutir as dimensoes da relacao bilateral Brasil-China, a configuracao de um paradigma neoglobalista para a politica externa chinesa. Alem disso, apresenta indefinicoes estrategicas que intervem na insercao internacional do dragao oriental. Por fim, debate-se a intervencao chinesa no espaco amazonico.
TL;DR: The nearest-neighbor-interaction spin-1 Ising model is investigated within the damage-spreading approach, and precise estimates of their associated critical exponents and of the critical temperature of the model are obtained, in spite of the small lattice sizes considered.
Abstract: The nearest-neighbor-interaction spin-1 Ising model is investigated within the damage-spreading approach. Exact relations involving quantities computable through damage-spreading simulations and thermodynamic properties are derived for such a model, defined in terms of a very general Hamiltonian that covers several spin-1 models of interest in the literature. Such relations presuppose translational invariance and hold for any ergodic dynamical procedure, leading to an efficient tool for obtaining thermodynamic properties. The implementation of the method is illustrated through damage-spreading simulations for the ferromagnetic spin-1 Ising model on a square lattice. The two-spin correlation function and the magnetization are obtained, with precise estimates of their associated critical exponents and of the critical temperature of the model, in spite of the small lattice sizes considered. These results are in good agreement with the universality hypothesis, with critical exponents in the same universality class of the spin- 12 Ising model. The advantage of the present method is shown through a significant reduction of finite-size effects by comparing its results with those obtained from standard Monte Carlo simulations.
01 Jan 2008
TL;DR: In this paper, the authors examine the urban structure of Roraima State, in order to understand the Boa Vista City function on that context, due the urban influence done by that city.
Abstract: A estrutura urbana de Roraima aqui e analisada atraves da Geografia, buscando entender esse lugar, atraves de suas singularidades, no que se refere a estrutura urbana local. Examinamos a estrutura urbana do estado de Roraima, para entender o papel de Boa Vista nesse contexto, em funcao da primazia urbana exercida por essa cidade. Refletimos os processos determinantes para esse arranjo da urbanizacao, onde se configura uma macrocefalia urbana numa fronteira politica e de assentamento. Investigamos a relacao entre espaco e tempo para entendermos as diferentes acoes que aqui se impuseram e o movimento do fenomeno urbano e suas singularidades locais. Sendo assim, destacamos que, apesar da simplicidade do conjunto urbano roraimense, com apenas 15 cidades, tem-se uma diferenca deste com relacao ao restante da Amazonia, demonstrada nao somente pela concentracao na capital, em detrimento das demais cidades, mas porque a capital roraimense e o centro de uma rede urbana dendritica, apresentando novas tendencias de polaridade na ultima fronteira do Brasil. Palavras-chave: Amazonia. Roraima. Rede Urbana. Abstract The Roraima urban structure is analyzed hereby through Geography, seeking to understand this place, troughs their singularities, referring to local urban structure. We examine the urban structure of Roraima State, in order to understanding the Boa Vista City function on that context, due the urban influence done by that city. Let think the determinant processes for organization, where display an urban macro encephalic on politic border and occupation. Let investigate the relation between space and time for understanding the different actions that imposed here and the urban phenomenon and their local singularities. This way, we insight that despite of simply of set urban in Roraima with 15 counties, have a difference to Amazon other places, displayed, no just by concentrated people in the Capital, on detriment of other cities, but the Roraima capital is the dendritic urban net, showing new polarity tendency on the last border of Brasil. Key-words: Amazon. Roraima. Urban net