Showing papers by "Federal University of Roraima published in 2007"

An ecoregional classification for the state of Roraima, Brazil: the importance of landscape in malaria biology.

Abstract: Understanding the different background landscapes in which malaria transmission occurs is fundamental to understanding malaria epidemiology and to designing effective local malaria control programs. Geology, geomorphology, vegetation, climate, land use, and anopheline distribution were used as a basis for an ecological classification of the state of Roraima, Brazil, in the northern Amazon Basin, focused on the natural history of malaria and transmission. We used unsupervised maximum likelihood classification, principal components analysis, and weighted overlay with equal contribution analyses to fine-scale thematic maps that resulted in clustered regions. We used ecological niche modeling techniques to develop a fine-scale picture of malaria vector distributions in the state. Eight ecoregions were identified and malaria-related aspects are discussed based on this classification, including 5 types of dense tropical rain forest and 3 types of savannah. Ecoregions formed by dense tropical rain forest were named as montane (ecoregion I), submontane (II), plateau (III), lowland (IV), and alluvial (V). Ecoregions formed by savannah were divided into steppe (VI, campos de Roraima), savannah (VII, cerrado), and wetland (VIII, campinarana). Such ecoregional mappings are important tools in integrated malaria control programs that aim to identify specific characteristics of malaria transmission, classify transmission risk, and define priority areas and appropriate interventions. For some areas, extension of these approaches to still-finer resolutions will provide an improved picture of malaria transmission patterns.

Árvores frutíferas nos quintais urbanos de Boa Vista, Roraima, Amazônia brasileira

Abstract: O objetivo do trabalho foi estimar a riqueza e a diversidade das especies de arvores frutiferas cultivadas nos quintais caseiros da cidade de Boa Vista, Roraima, bem como determinar quais sao as especies cultivadas preferencialmente pela populacao urbana local. Os levantamentos foram realizados em dois bairros surgidos com a expansao da cidade em 1982: (1) BEst - Bairro dos Estados (Zona Norte) e (2) BAsa - Bairro Asa Branca (Zona Oeste). Foram observados 722 quintais no BEst (06 a 22.03.2004) e 339 no BAsa (07.04 a 01.07.2004). Trinta e seis especies (19 familias botânicas) foram encontradas no BEst e 37 (20 familias) no BAsa, configurando um total de 43 especies (20 familias) observadas. Deste total, 30 especies (69,8%) de 19 familias (95%) ocorreram em ambos os bairros, sugerindo preferencias frutiferas comuns. Os tres maiores indices de valor de preferencia (IVP) foram coincidentes e registrados para coco (Cocos nucifera L. - BEst: 19,4% e BAsa: 20,5%), manga (Mangifera indica L. - BEst: 14,9% e BAsa: 22,5%) e jambo (Syzygium malaccence (L.) Merr. & L.M. Perry - BEst: 10,5% e BAsa: 10,1%), todos de origem externa a Amazonia, mas que congregaram conjuntamente 44,9% (BEst) e 53,0% (BAsa) de IVP. Estes resultados sugerem que o cultivo de arvores frutiferas em quintais caseiros de Boa Vista segue um padrao que concentra a escolha em poucas especies, nao-originarias da Amazonia, mas tradicionalmente consagradas por seu exito na producao de frutos.

Affinity and diversity indices for anopheline immature forms

Abstract: As for the entire Amazon Region, malaria continues to be a major health public problem in Roraima that presented an Annual Parasitic Index of 85.4 in 2005, the highest in Brazil. Information on anopheline breeding sites is an essential component in malaria control strategies. Aiming to contribute to the limited knowledge on anopheline immature forms in Roraima, collections and breeding site observations were performed in 10 breeding sites around the capital city Boa Vista. Collections were carried out in the rainy and dry season periods between April 2004 and January 2005. Breeding sites comprised natural and artificial water reservoirs. A total of 623 immature forms were collected belonging to Anopheles albitarsis s.l., An.triannulatus s.l., An. nuneztovari/dunhami, An. braziliensis, An. evansae, An. oswaldoi s.l., An. strodei and An. darlingi. An. albitarsis and An. braziliensis were the most frequently found species. Eight larvae of An. darlingi were found in only one breeding site located in the forest. An. triannulatus/An. nuneztovari and An. albitarsis/An. braziliensis were the pairs of species that mostly occurred together. Both pair of species displayed the highest affinity index what might indicate a high compatibility for the same breeding conditions and/or a synergistic co-occurrence. Species diversity index was higher for the dry season.

Etnopedologia e transferência de conhecimento: diálogos entre os saberes indígena e técnico na Terra Indígena Malacacheta, Roraima

Abstract: Ethnopedology deals mainly with indigenous knowledge on pedo-diversity. In this sense, the agricultural and cultural traditions of the Wapishana Indians in Roraima, of the Arawak linguistic background, constitute a relevant pool of ethno-scientific knowledge in Amazonia. The Federal University of Roraima has increasingly acknowledged their importance in the Indigenous Education undergraduate courses. In this study, the ethnopedological classifications of the Wapishana Indians were confronted with the Brazilian System of Soil Classification in a soil survey of the Malacacheta Indian Territory. The ethnopedological classification of Wapishana Indians identifies and separates all environmental segments of the area, relating easily recognizable aspects of the soilscape (color, texture, depth, vegetation) with observable aspects (land use, cultivation type, suitability). The Wapishana classify eight basic soil types, that occur either separately or in associations: Imii Wyzda'u (Yellowish earth), Imii Wyza'u (Red earth), Imii Pudiidiu (Black Earth), Imii Pudiidiza'u (Dusky-Red Earth), Katy Bara Pudiidiu (Sandy loam), Imii Kaxidia'u (Black spongy), Imii Katy Bara Pudiidiu Naik Baraka'u (Black and White Sandy Ground) and Imii Wyzadaza'u Rik Pudiidiu (Mixed Yellowish earth, Dusky-Red earth and Rock outcrops), based on morphological, physical and chemical attributes, as well as land use limitations. There are clear relationships between the ethnopedological knowledge and the ethno-ecological dimension of the Wapishana culture, in the broadest sense. The ethnopedological observations, thus, represent an expression of the interwoven network of man-environment relationships, seen in a framework of universal principles of human/landscape ecology. The intense ethnopedological dialogue between soil scientists and Indians resulted in enriching, mutually beneficial contributions: the proper knowledge transfer in loco between two different traditions, the clarification of great part of the ethnopedological perceptions of both groups, and the understanding on how and why each group identified a given soil. Moreover, a soil map based on indigenous knowledge was drawn up, in an extrapolation of the cartographical base available to pedologists; this supported the conventional soil mapping of the area as well, especially in the recognition of soil inclusions and associations. Particularly, the experience allowed effective communication and approach of the representatives of indigenous and technical knowledge, based on knowledge transfer and mutual discoveries of understanding, creating synergy effects with promising results, which outreached the original aim of soil mapping of the Malacacheta Indian Territory.

Morphological analysis and re‐examination of the taxonomic circumscription of Acosmium (Leguminosae, Papilionoideae, Sophoreae)

Abstract: Acosmium Schott is a Neotropical genus ofca. 17 species of trees with non-papilionoid, actinomorphic flowers. It has been included in the genistoid clade (Leguminosae, Papilionoideae) in recent phylogenetic analyses. A morphology-based cladistic analysis was performed to test the currently assumed monophyly of Acosmium, assess the validity of the infrageneric classification of Yakovlev, and detect synapomorphies and other diagnostic characters in Acosmium and related taxa. Thirty-four species representing ten genera of subfamily Papilionoideae were included in the analysis: all accepted species of the four sections of Acosmium together with species of Bowdichia, Clathrotropis, Diplotropis, Bolusanthus, Cadia, Poecilanthe, Cyclolobium, and Ormosia; two species of Luetzelburgia were selected as outgroups. The results do not support the monophyly of Acosmium; the species of this genus fall into three distinct, not closely related clades that correspond to the sections of Acosmium established by Yakovlev except for sect. Mesitis that merges into sect. Leptolobium. We propose: (1) recognizing a narrowly circumscribed genus Acosmium; (2) reinstating the generic name Leptolobium Vogel, encompassing sections Leptolobium and Mesitis; and (3) segregating A. praeclarum (Sandwith) Yakovlev into a new genus, Guianodendron. The phylogenetic relevance of some new or neglected characters, especially from bud architecture, seed, and seedling morphology is emphasized.

Morfologia de plântulas de cinco leguminosas genistóides arbóreas do Brasil (Leguminosae-Papilionoideae)

Abstract: This work aims to describe, illustrate and compare the seedling morphology of five tree species of the genera Bowdichia, Cyclolobium, Diplotropis, Ormosia, and Poecilanthe, which belong to the genistoid clade (Leguminosae Papilionoideae). Phanero-epigeal-foliaceous seedlings are found in Bowdichia virgilioides Kunth, Cyclolobium brasiliense Benth. has phanero-epigeal-reserve seedlings, while Ormosia arborea (Vell.) Harms, Diplotropis martiusii Benth., and Poecilanthe parviflora Benth. possess crypto-hypogeal-reserve seedlings. Some other relevant seedling morphological characters are discussed and compared with those of previously studied species in these genera.

Distribution summaries of malaria vectors in the northern Brazilian Amazon.

Abstract: Knowledge of vector distribution is important for the design of effective local malaria control programs. Here we apply ecological niche modeling to analyze and predict the distributions of malaria vectors based on entomological collection points in the State of Roraima in the northern Brazilian Amazon Basin. Anopheline collections were conducted from 1999 to 2003 at 76 localities, all with active malaria transmission. A total of 13 anopheline species was identified from 17, 074 adult females collected: Anopheles darlingi, An. albitarsis s.l., An. nuneztovari, An. triannulatus s.l., An. braziliensis, An. peryassui, An. oswaldoi s.l., An. mattogrossensis, An. strodei, An. evansae, An. squamifemur, An. mediopunctatus s.l., An. intermedius. Anopheles darlingi, and An. albitarsis were the most frequently found species. An. squamifemur was found for the first time in Roraima. A distributional prediction model (genetic algorithm for rule-set prediction-GARP) and environmental variables were used to pre...

Effects of δ-baryon interaction strength on neutron stars properties

Abstract: We investigate the effect of Δ-resonance interaction strength on the equation of state of asymmetric hadronic matter and neutron stars structure. We discuss Δ-matter formation at high densities in the context of a relativistic mean field theory. We show that the attractive nature of the Δ-baryon interaction can induce a phase transition accompanying Δ-matter formation, at values of densities presumably existing in central regions of neutron stars. The possibility of a rich Δ-resonance neutron star is presented using the proposed equation of state.

Seedling morphology in the Vatairea clade (Leguminosae, Papilionoideae)

Abstract: RESUMO O clado Vatairea sensu Mansano et al. (Leguminosae, Papilionoideae) e constituido pelos generos Luetzelburgia, Sweetia, Vatairea e Vataireopsis, dentre os quais informacoes sobre plântulas sao restritas a Vatairea e Vataireopsis. Neste trabalho, plântulas de Luetzelburgia guaissara Toledo e Sweetia fruticosa Spreng. sao descritas e ilustradas. Luetzelburgia guaissara possui plântulas fanero-epigeo-armazenadoras, enquanto que Sweetia fruticosa apresenta plântulas cripto-hipogeo-armazenadoras. E apresentada uma breve revisao da morfologia de plântulas dos representantes do clado Vatairea, bem como uma chave de plântulas para a identificacao de seus generos. A variacao dos tipos morfologicos e de alguns caracteres como numero de foliolos, presenca de catafilos, projecao basal no colo e tipo de nictinastia foliolar apresenta relevância sistematica para distincao de generos neste clado.

Synthesis, characterization, solid state and aqueous solution fluorescence study for lanthanide-crown ether-terpyridine complexes

Abstract: The complexes [Eu(12-crown-4)(terpy)(H2O)]3Cl, [Eu(15-crown-5)(terpy)]3Cl, [Tb(12-crown-4)(terpy)(H2O)]3Cl, [Tb(15-crown-5)(terpy)]3Cl, [Gd(12-crown-4)(terpy)(H2O)]3Cl and [Gd(15-crown-5)(terpy)]3Cl (terpy = 2,2′,6′,2′′-terpyridine) were synthesized and characterized by CHN elemental analysis, infrared spectroscopy and fluorescence spectroscopy. Emission spectra were obtained on both, solid state and aqueous solutions for europium and terbium complexes. The complexes exhibit good emission, even in aqueous solution, enhancing their potential for biological applications. The reduction of emission intensity, from solid state to aqueous solution, is lower for europium complexes, in comparison to terbium complexes. The [Eu(12-crown-4)(terpy)(H2O)] · 3Cl complex exhibits an emission lifetime of 0.64 ms while [Eu(15-crown-5)(terpy)] · 3Cl exhibits a value of 0.38 ms. Furthermore, the 15-crown-5 complex emission intensity is about 3.8 times larger than the emission intensity of the 12-crown-4 complex. This ratio ...

Os lagos do lavrado de Boa Vista - Roraima: fisiografia, físico-química das águas, mineralogia e química dos sedimentos

Abstract: The landscape of northeast portion of the Roraima state is formed by a plain surface, covered by savanna, where many lakes, wetlands and Mauritia flexuosa paths occur. These lakes exhibit several shapes, but the most frequent ones are drop-shape, circular, ellipsoid and twin shapes, being generally related to small water courses (igarapes) like its headwaters. The lacustrine basins are very small and shallow. The water’s level is seasonally controlled, during the drought season several lakes, wetlands and paths dry and stress the grassy ones and the Mauritia flexuosa. The lakes vegetation is compost by dense communities of aquatic macrophytes, mainly for Cyperaceae, which occupies whole lake or distributes in a circular and concentric zone, with a deeper and bubbling center area, indicative of water spring. The lakes don’t present own fine sediments, its substratum’s material is mostly sandy and the grains show no roundness until to low roundness as well as low sphericity. They are essentially constituted of quartz, being less frequent kaolinite. The chemical composition displays high concentrations of SiO2 and low values of Al2O3 and Fe2O3 allowing to correlate them to Boa Vista Formation sediments. The external and internal lacustrine features suggest that occurrence of these lakes in savanna environment are related to near surface groundwater, that during the rainy season intercepts the shallow land surface depressions, in the form of springs forming the lakes and wetlands. The whole landscape of lakes formed by green and open fields represents a singular lake system in the Amazon region which due the accelerate and disordered urban expansion of the Boa Vista city suffers environmental impacts including the extinction of many lakes and alteration of the waters quality through of anthropogenic activities such as clothes laundering and end destination of domestic effluents.

Avaliação de cultivares de alface em ambiente protegido em Boa Vista, Roraima, Brasil

Abstract: This study evaluated the growth and yield of six lettuce cultivars under protected cultivation. The experimental design was randomized blocks with six treatments and four replications. The cultivars Hortencia, Rubra, Monica SF1, Regina de Verao, Veronica and Grandes Lagos 659 were evaluated. The air temperature under protected cultivation oscillated between 24,4oC and 31,5oC during the experimental period. Rubra and Grandes Lagos 659 showed the best performance with yields superior to 28,000 kg.ha-1 and fresh weight of 176,7g and 184,4 g, respectively.

Sistema internacional com hegemonia das democracias de mercado: desafios de Brasil e Argentina

Abstract: Um duro retrato da realidade internacional: esta talvez seja a frase que melhor sintetiza o livro de Eduardo Viola, professor titular de Relacoes Internacionais da Universidade de Brasilia, e Hector Ricardo Leis, professor da Universidade Federal de Santa Catarina. Apos quase vinte anos do colapso da Uniao Sovietica as transformacoes operadas no sistema internacional agora podem ser melhor percebidas: coube aos autores descreve-las de forma coerente e contundente. A linha central de pensamento dos autores e que o sistema de estados que delineia a ordem internacional vigente e baseado na hegemonia das democracias de mercado. Nesse sentido, o protagonismo norte-americano so e valido em composicao com outras grandes potencias: juntas, como democracias de mercado consolidadas, fazem da democracia seu modelo politico, do capitalismo de mercado sua moldura economica definidora e da globalizacao seu veiculo de manutencao ou transformacao da ordem vigente. Ainda que exaltando o verdadeiro liberalismo, a analise de ambos aponta para uma valorizacao do progresso social e economico como metas universais, em detrimento de orientacoes puramente ideologicas. O objetivo da obra e o de apresentar ao leitor inteligente um retrato realista da cena internacional do seculo 21, desenhada nao por incertezas e bifurcacoes, nem por antagonismos de classes e forcas sociais, mas pela certeza da preponderância do liberalismo em construir um mundo em consonância com as demandas sociais e com o objetivo de preparar as novas geracoes para lidar com a infinidade de velhos e novos desafios deste milenio, como terrorismo, pobreza e desigualdades globais, epidemias e problemas ecologicos (poluicao, desflorestamento, escassez de agua...). Para tanto, os autores dividem a obra em tres partes principais com cinco capitulos: tratam da rota de Brasil, Argentina e America do Sul rumo ao universo pos-historico das democracias de mercado. No primeiro capitulo, O sistema internacional com hegemonia das democracias de mercado no inicio do seculo XXI, os

Suplementação de lipídeos de diferentes fontes em dietas para vacas Jersey na fase inicial de lactação

Abstract: The objective of this research was to evaluate the effects of fat supplementations as calcium salts of palm oil (PF), whole rice bran + rice oil (WRBO) and whole rice bran + bovine tallow (WRBT) on dry matter intake, productive efficiency and energy balance of dairy cows in the beginning of the first third period of lactation. Control diet contained 2.9% EE, while the diets GP, FAIO and FAIS contained 5.13; 5.29 and 5.16% EE, respectively. Pure bred Jersey cows of 2nd and 3rd lactation were used, with 70 days in milk, average weight of 420 kg and body condition of 3.5 to 4. A replicated 4 x 4 Latin square experimental design was used, with eight cows, four diets and four experimental periods. Each experimental period consisted of 21 days (14 days for adaptation and 7 for sample collection for the chemical analysis of milk and feeds. Milk production of 3.5% fat corrected milk (FCM 3.5%) was higher with the fat supplementation to the diet. There was no difference in dry matter intake. Fat supplementation showed better results for productive efficiency expressed as FCM3.5% in function of metabolic weight. Independently of lipid source, there was not effect of the diets on PLC3.5%, dry matter intake and productive efficiency, expressed as PLC3.5% in function of the metabolic weight. The addition of different fat sources to high production dairy cows diets could be viable, because its addition to the diet improved milk yield without alter feed intake.

Qualidade do melão ‘Orange Flesh’ minimamente processado armazenado sob atmosfera modificada

Abstract: Este trabalho teve como objetivo avaliar o efeito da atmosfera modificada na qualidade do melao‘Orange Flesh’minimamente processado. Os cubos de meloes foram sanificados com 100 mg L -1 de hipoclorito de sodio por um minuto, lavados, drenados e embalados com diferentes concentracoes de O 2 e CO 2 em sacos plasticos de polietileno (Nylon Poli). Foram avaliados a cada dois dias durante dez dias quanto a firmeza, pectina total, pectina soluvel e atividade da polifenoloxidase e peroxidase. Ao final do periodo de conservacao, os produtos vegetais com modificacao da atmosfera mantiveram a textura mais firme e a concentracao de 5%O 2 + 3% CO 2 apresentaram menor teor de pectina total e juntamente com a concentracao de 100% N 2 o menor teor de pectina soluvel e nao apresentaram atividades de polifenoloxidase e peroxidase.

Frustrated model to describe reentrant behavior in copper oxide superconductors

Abstract: The quenched decorated Ising model with competitive interactions is used here to described the magnetic properties of the copper oxide superconductors compounds in the insulating phase (antiferromagnetic). The model consists of planes in which the nodal spins interact antiferromagnetically ( J A 0 ) with their nearest-neighbors, and ferromagnetically ( J F > 0 ) with the spins that decorate the bonds, which are quenched and distributed randomly over the two-dimensional lattice. The planes interact antiferromagnetically with weak-exchange interaction (i.e., J A ′ = λ J A , λ = 10 - 5 ). By using the framework of an effective-field theory, based on the differential operator technique, we discuss the antiferromagnetic-phase stability limit in the temperature-decorated bond concentration space ( T - p ), for λ = 10 - 5 and various values of frustration parameter α = J A / J F . For certain region range of the parameter α we observe a reentrant behavior at low-temperature. We also discuss the critical behavior of T N versus α for some values of decorated bond concentrations and reentrant phenomena is observed. We calculate the dependence of the staggered magnetization as a function of the temperature to analyze the reentrant behavior observed in the phase diagrams.

Modified Brans-Dicke theory of gravity from five-dimensional vacuum

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 in the framework of general relativity. We show that the 5D Brans-Dicke vacuum equations when reduced to four dimensions lead to a modified version of Brans-Dicke theory in four dimensions (4D). As an application of the formalism, we obtain two five-dimensional extensions of four-dimensional O'Hanlon and Tupper vacuum solution and show that they lead two different cosmological scenarios in 4D.

A agroindústria canavieira paraibana: implicações da crise no emprego e na arrecadação tributária na década de 1990

Abstract: O objetivo do trabalho e identificar as implicacoes socioeconomicas da crise na agroindustria canavieira paraibana na decada de 1990. Os dados foram obtidos junto ao Instituto Brasileiro de Geografia e Estatistica, Associacao dos Plantadores de Cana-de-Acucar da Paraiba, Secretaria de Planejamento do Estado da Paraiba e Instituto de Pesquisa Economica Aplicada. Os resultados mostram que as principais consequencias da crise na agroindustria canavieira paraibana foram a queda no numero de empregos, que estimulou o exodo rural e a reducao na renda, dada pelo encerramento das atividades de seis unidades industriais. Com isso, a producao caiu e a arrecadacao tributaria do Estado apresentou uma diminuicao significativa, principalmente nos setores primario e secundario.

[Development of the fungi Metarhizium anisopliae (Metschnikoff, 1879) Sorokin, 1883 and Beauveria bassiana (Balsamo) Vuillemin, 1912 on the Ctenophephalides felis felis (Bouché, 1835)].

Abstract: The flea Ctenocephalides felis felis is a parasite that causes allergic dermatitis and also may transmit etiologic agents to domestic animals and humans. This study investigated by scanning electron microscopy the development of entomopathogenic fungi on flea cuticle. Fleas were exposed to conidia (10(8) ml(-1)) of Metarhizium anisopliae (isolate 959) or Beauveria bassiana (isolate 986). Following standard protocols for electron microscopy, the specimens were prepared 2, 15, 26 and 96 h after infection. The micrography revealed that 2 h after fungus exposure, conidia attachments encompassed the entire flea cuticle, especially on abdominal intersegmental membranes. The emergence of germ tubes and appressoria formation occurred at 15 h, thickening and branching of hyphae on the flea cuticle was noted at 26 h. Therefore, both of these fungal isolates were able to develop on cuticular surfaces of C. f. felis.

A construção do sujeito nas narrativas orais.

Abstract: Este artigo, considerando a perspectiva da identidade como algo multiplo, hibrido e em constante mudanca, objetiva discutir como se da a construcao do sujeito nas narrativas orais. Sujeito este socio historico e culturalmente situado, que constroi o mundo e e construido por ele dentro do discurso a partir de sua interacao dialogica com seu interlocutor. O objeto que se apresenta como foco principal e a construcao de identidades indigena, utilizando para isto recortes de narrativas orais dos grupos: Xukuru de Ororuba (Municipio de Pesqueira - Pernambuco), Shawandawa ou Arara (Municipio de Cruzeiro do Sul - Acre e Makuxi (Municipio de Normandia - Roraima), entre outros.

Synthesis, characterization and thermogravimetric study of Dy and Sm 12-crown-4 bipy, terpy and phen complexes

Abstract: The synthesis, characterization and thermogravimetric study of [Sm(12C4)(H2O)4]Cl3, [Dy(12C4)(H2O)4]Cl3, [Sm(12C4)(bipy)(H2O)2]Cl3, [Dy(12C4)(bipy)(H2O)2]Cl3, [Sm(12C4)(bipy)(phen)]Cl3, [Dy(12C4)(bipy)(phen)]Cl3, [Sm(12C4)(phen)2]Cl3, [Dy(12C4)(phen)2]Cl3, [Sm(12C4)(terpy)(H2O)]Cl3 and [Dy(12C4)(terpy)(H2O)]Cl3 (12C4 = 12-crown-4; bipy = bipyridine; phen = 1,10-phanathroline; terpy = terpyridine) are reported. All compounds exhibit CN = 8 and four oxygen–lanthanide bonds of the crown ether provide a very stable (from the thermal point of view) chemical environment, since the crown ether molecules are the last organic moiety to be released under heating.

Growing of the inhomogeneities and acceleration phase in a universe with lambda decay

Abstract: We study a model with decay of dark energy and creation of the dark matter particles. We integrate the field equations and find the transition redshift where the evolution process of the universe change from decelerated to an accelerated phase expansion, and briefly discuss the transition epoch and the broken of the strong energy condition. Finally, we examine the growing of the inhomogeneities.

Beleza e Vício: O olhar etnográfico dos irmãos Schomburgk (1835-1844)

Abstract: Neste ensaio tentamos ‘desenterrar’ e analisar alguns dos alicerces paradigmaticos do ‘olhar etnografico’ que informa as anotacoes sobre povos nativos na ‘regiao circum-Roraima’ (Colson) nos escritos (publicados e ineditos) dos irmaos Robert-Hermann e de Richard (Moritz) Schomburgk, ‘naturalistas’ alemaes da primeira metade do seculo XIX.

Synthesis, characterization and tg-dsc study of lanthanide trifluoroacetate-2-azacyclononanone compounds

Abstract: The synthesis, characterization and tg-dsc study of Ln(tfa)3 · 3aza where Ln = La, Pr, Nd, Sm, Eu, Gd, Tb and Er, tfa = trifluoroacetate and aza = 2-azacyclononanone are reported. The obtained X-ray powder diffraction patterns show that the compounds are divided in two isomorphous groups: La, Pr, Nd and Eu, Sm, Gd, Tb and Er. For all compounds, the thermodegradation under nitrogen gave the respective oxifluorides (LnOF) as the final product. The melting temperature intervals are 105–110°C, 100–112°C, 90–95°C, 79–101°C, 65–70°C, 75–90°C, 64–76°C and 50–65°C for the La, Pr, Nd, Sm, Eu, Gd, Tb and Er compounds, respectively, and it is verified that the lanthanide contraction induces a weaker intermolecular interaction between adjacent molecules in the solid state.