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.

Anomaly in the phase diagram of the spin quantum 1/2 anisotropic Heisenberg antiferromagnet model with Dzyaloshinskii-Moriya interaction: A low temperature analysis

Abstract: We will study phase diagram the quantum spin-1/2 anisotropic Heisenberg antiferromagnet model in the presence of a Dzyaloshinskii–Moriya interaction ( D ) and a uniform longitudinal ( H ) magnetic field, where we have observed an anomaly at low temperatures. Using the effective-field theory with a finite cluster N =2 spin (EFT-2) we calculate the phase diagram in the H – D plane on a simple cubic lattice ( z =6). We analyzed the cases: anisotropic Heisenberg – case I: ( Δ = 1 ) , anisotropic Heisenberg – case II: ( Δ = 0.5 ) and anisotropic Heisenberg – case III: ( Δ = 0 ) , where only second order phase transitions are observed.

Carcass characteristics of lambs fed diets with mulberry hay

Abstract: Objetivou-se avaliar as caracteristicas quantitativas in vivo, da carcaca e dos cortes comerciais de cordeiros alimentados com dietas contendo 0; 12,5 e 25,0% de feno de amoreira em substituicao ao concentrado. Foram utilizados vinte e quatro cordeiros Ile de France, com aproximadamente 60 dias de idade e 15 kg de peso corporal, confinados em baias individuais e abatidos aos 32 kg. Houve efeito linear crescente (R2 = 0,84) para a profundidade do torax, indice de musculosidade da perna (R2=0,71) e para a relacao musculo:osso (R2=0,95); decrescente (R2 =0,75) para o indice de compacidade da carcaca, peso da paleta (R2 = 0,78) e peso (R2=0,99) e comprimento (R2=0,86) do femur a medida que se aumentou o feno de amoreira na dieta; e comportamento quadratico para perdas por resfriamento (R2=1,0) e porcentagem de gordura intermuscular. O feno de amoreira pode ser utilizado na alimentacao de cordeiros confinados sem prejudicar as caracteristicas quantitativas da carcaca.

Cemitério x novo coronavírus: impactos da covid-19 na saúde pública e coletiva dos mortos e dos vivos

Abstract: O referido artigo tem como objetivo discutir como os impactos do novo coronavirus (Sars-CoV-2) e da doenca (covid-19) afetam na saude publica e coletiva refletindo sobre o contagio dos profissionais em cemiterios, necroterios e servicos funerarios que lidam de frente com a pandemia que afeta todos os continentes. A pesquisa e de cunho bibliografico e descritivo sob a otica da abordagem exploratorio e qualitativa, com intuito de familiarizar-se com a problematica da saude, cemiterios e o novo coronavirus. Os resultados partem da analise de conteudo que demonstram que a morte tambem polui, e que os cemiterios podem armazenar elementos de alto risco de contaminacao como bacterias, virus e protozoarios que podem se proliferar pela inumacao, tumulacao e cremacao, se estes nao forem bem instalados e gerenciados. Conclui-se que devido as grandes ocorrencias de casos a partir do novo coronavirus as autoridades cientificas, o poder publico e sociedade necessitem discutir e refletir sobre as questoes socioambientais que envolvem a relacao dos cemiterios e do sepultamento de cadaveres frente as pandemias.

On some aspects of gravitomagnetism in scalar-tensor theories of gravity

Abstract: We discuss the gravitomagnetism in the context of scalar-tensor theories of gravity. We obtain the equation of motion of a particle in terms of gravitoelectric and gravitomagnetic fields. We discuss the gravitomagnetic time delay and the Lense-Thirring effect in the context of scalar-tensor theories of gravity. In the particular case of Brans-Dicke Theory, we compare the results obtained with those predicted by general relativity and show that within the accuracy of experiments designed to measure these effects, both theories predict essentially the same results.

Eficiéncia fotosintética y de uso del agua por malezas

Abstract: The objective of this study was to evaluate characteristics associated with the photosynthetic efficiency and water use of weed species. Treatments were composed by the species Bidens pilosa, Commelina benghalensis and Brachiaria plantaginea, sown individually in the experimental units. The experimental design was in randomized blocks in a 3 x 4 factorial, with three repetitions. Characteristics associated with water use - transpiratory rate (E), stomatal conductance (Gs), vapor pressure in the substomatal chamber (Ean) and water use efficiency (WUE) - as well as photosynthesis - internal leaf CO2 concentration (Ci), CO2 consumed during the evaluation (ΔC),leaves average temperature at evaluation time (Tleaf) and photosynthetic rate (A) - were evaluated. B. plantaginea showed lower E, lower WUE and higher A and Ci, differing from the other involved species. B. pilosa showed lower values of WUE, A and T when compared to the other species. According to the results, it can be concluded that B. plantaginea was more efficient in characteristics related to the photosynthesis, i.e., more efficient use of light. B. pilosa was more efficient in characteristics related to water use.