Federal University of Roraima

About: Federal University of Roraima is a based out in . It is known for research contribution in the topics: Population & Thermogravimetry. The organization has 981 authors who have published 1218 publications receiving 7849 citations. The organization is also known as: Federal University of Roraima.

Expansão urbana e exclusão social em Boa Vista - Roraima

Abstract: O presente artigo aborda as relacoes existentes entre o processo de expansao urbana, crescimento demografico e exclusao social na capital do estado de Roraima, Boa Vista. A partir de uma perspectiva historica, busca‑se apresentar os principais agentes envolvidos no processo de expansao urbana da cidade e a situacao atual concernente a alguns indicadores sociais nela observados. Palavras-chave : Crescimento demografico. Exclusao social. Expansao urbana.

Decomposition of aquatic macrophytes from Cantá stream (Roraima, Brazil): kinetics approach

Abstract: AIM: This study aimed at describing and comparing the kinetics of aerobic and anaerobic decomposition of Eleocharis interstincta, Nymphaea sp. and Montrichardia arborescens; METHODS: The samples of aquatic macrophytes and water were collected in the Canta Stream (02° 49' 11" N and 60° 40' 24" W), Canta, Roraima, Brazil. The plant material was dried and triturated and for each experimental condition (aerobic and anaerobic) mineralization chambers were prepared with plant fragments and stream water. The volume of evolved gases in anaerobic mineralization was monitored during 78 days, while the oxygen consumption was measured for 121 days; RESULTS: The results of aerobic and anaerobic decomposition were fitted to first-order kinetics model. The oxygen consumption varied from 195.36 mg g-1 (DM) for E. interstincta to 629.46 mg g-1 (DM) for Nymphaea sp. The deoxygenation rate derived from mineralization of M. arborescens was higher (kD: 0.049 day-1), followed by E. interstincta (kD: 0.038 day-1) and Nymphaea sp. (kD: 0.027 day-1). For the anaerobic condition the evolution of gases presented two phases: the consumption and formation. According to temporal variations of mineralized carbon, the anaerobic decomposition of M. arborescens presents the higher mineralization coefficient (0.0047 day-1); followed by Nymphaea sp. (0.0035 d-1) and E. interstincta (0.0017 day-1); CONCLUSION: Based on these results we conclude that during the aerobic decomposition of these macrophytes, the Nymphaea sp. was responsible for the higher oxygen demand and M. arborescens generated the highest amounts of gases during the anaerobic mineralization. On average, the aerobic decay processes were 11-fold faster than anaerobic. Regarding to the materials fluxes in freshwater ecosystems, low rate of decomposition observed in anaerobic process when comparing to aerobic rates reflect that the sediment represent a very efficient sink of carbon in the organic matter cycling.

Fatores de risco associados à prevalência de anticorpos anti-Sarcocystis neurona, Neospora spp. e Toxoplasma gondii em equinos de Roraima, Amazônia

Abstract: RESUMO: Amostras de sangue de 303 equinos provenientes de 56 propriedades do municipio de Rorainopolis, Roraima, foram avaliadas por Reacao de Imunofluorescencia Indireta (RIF) para pesquisa de anticorpos contra Sarcocystis neurona, Toxoplasma gondii e Neospora spp. Algumas amostras de soros positivos para Sarcocystis spp. foram avaliadas pelo Western Blotting (WB) utilizando antigenos crus de S. neurona. A partir dos resultados sorologicos, possiveis fatores de risco foram avaliados frente a variaveis individuais e de propriedade. A prevalencia de anticorpos anti-Sarcocystis spp. foi estimada em 43,2% (37,6-49,0%), anti-Neospora sp. em 26,7% (21,9-32,2%) e anti-T. gondii de 18,5% (14,3-23,4%). Quatorze amostras (14/15) testadas por WB resultaram positivas para antigenos de S. neurona. Das propriedades, 76,8% (43/56) apresentaram pelo menos um equino positivo para Sarcocystis spp.; 69,6% (39/56) para Neospora spp. e 55,4% (31/56) para T. gondii. Dos equinos, 13 (4,3%) apresentarem anticorpos para os tres agentes, 50 (16,5%) para Sarcocystis spp. e Neospora spp., 10 (3,3%) para Neospora spp. e T. gondii, e oito (2,6%) para Sarcocystis spp. e T. gondii. As variaveis associadas (P≤0,05) a presenca de anticorpos foram: para Neospora spp. nao pastejar em areas alugadas, ausencia de assistencia veterinaria na propriedade, sexo masculino, nao estabular animais e plantel equino acima de 5 animais; enquanto para T. gondii foram o contato com felinos, animais da raca lavradeiro, animal estabulado, criacao de bovinos na propriedade e plantel equino acima de 5 animais. Nao houveram variaveis associadas a presenca de anticorpos contra S. neurona. Relata-se no presente estudo a primeira deteccao de anticorpos anti-S. neurona, Neospora spp. e T. gondii em equinos do estado de Roraima, localizado na Amazonia Setentrional Brasileira, ressaltando para a elevada frequencia de fazendas com equinos soropositivos.

Population fluctuations in the pink hibiscus mealybug and its natural enemies in Annona squamosa (Annonaceae) in Roraima, Brazil.

Abstract: Maconellicoccus hirsutus (Hemiptera, Pseudococcidae), a species of economic interest, especially for fruit plants, is expanding on the South American continent. Information about the population dynamics of this pest associated with control by natural enemies and cultural practices is fundamental for its management. Our objective was to study the population fluctuations in M. hirsutus and its natural enemies in a sugar-apple (Annona squamosa) orchard in Roraima, northern Brazil. Trees were evaluated monthly over a 12-month period. Infestation rates by M. hirsutus and its parasitism were also estimated for potential host plants around the study area. Highest infestation occurred in August and February-March. Alternative hosts were infested during the off-season, mainly fruit. Lacewings and the parasitoid Anagyrus kamali (Hymenoptera, Encyrtidae) were abundant natural enemies. Average parasitism by A. kamali in fruits was 50%, with highest rates in periods of greatest infestation by M. hirsutus. Fruitification pruning reduced M. hirsutus populations.

Mobilidade humana e trabalho

Abstract: O presente artigo visa compreender o processamento da mobilidade humana laboral de brasileiros, em busca de trabalho que transcorre na fronteira do Brasil com a Republica Cooperativista da Guiana, na cidade brasileira de Bonfim, em Roraima, com a cidade de Lethem, na Guiana. Nesse contexto, este estudo demonstra como se concretiza a ocorrencia da mobilidade humana e a ordenacao do universo do trabalho no contexto da globalizacao da economia, proporcionando um maior entendimento acerca desta tematica de natureza multidisciplinar, com perspectivas distintas, dispondo conceitos capazes de dar atencao a complexidade desse fenomeno migratorio que ocorre nessa transfronteira, enfatizando as relacoes cotidianas da populacao dessa regiao, por meio do enlacamento dessas comunidades translocais, bem como das transformacoes que ocorrem nesse espaco e que tem proporcionado mudancas de natureza economica, cultural, politica e social para os migrantes fronteiricos.