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.

Evaluation of resistance to pyrethroid and organophosphate adulticides and kdr genotyping in Aedes aegypti populations from Roraima, the northernmost Brazilian State.

Abstract: Roraima, the northernmost State in Brazil, borders Venezuela and Guyana. Although mostly covered by the tropical forests, the urban centers of this state are highly infested with Ae. aegypti and are endemic for dengue, Zika and chikungunya. We accessed the insecticide resistance status of Ae. aegypti populations from the capital Boa Vista, two cities on international borders (Pacaraima and Bonfim) and Rorainopolis bordering Amazonas State, in order to evaluate the chemical control efficacy in these localities. Tests with World Health Organization (WHO)-like tubes impregnated with the pyrethroid deltamethrin (0.05% and 0.12%) and the organophosphate malathion (0.7%) were conducted with Ae. aegypti from Boa Vista, Pacaraima, Bonfim and Rorainopolis, collected in 2016 and 2018. Genotyping of kdr mutations, related to resistance to pyrethroids, was performed for the SNP variations at sites 1016 and 1534 of the voltage gated sodium channel gene (NaV) with a TaqMan qPCR approach. Aedes albopictus was absent in our collections, and therefore only Ae. aegypti was tested. All Ae. aegypti populations were susceptible to 0.7% malathion in 2016; however, mortality dropped to under 90% in Bonfim and Pacaraima populations in 2018. All populations were resistant to 0.05% deltamethrin in both years. The time that 50% of females suffered knockdown (KdT50) under exposure to 0.05% deltamethrin was 3.3–5.9-fold longer in mosquitoes from the natural populations compared to the susceptible Rockefeller strain. Only the Pacaraima population (2018) remained resistant to 0.12% deltamethrin. Kdr genotyping revealed the absence of the wild-type NaVS haplotype (1016Val + 1534Phe) in the populations from Roraima, indicating that all tested insects had a genetic background for pyrethroid resistance. The double kdr NaVR2 haplotype (1016Ile + 15434Cys) was present in higher frequencies in all populations except for Rorainopolis, where this haplotype seems to have arrived recently. These results are important for the knowledge about insecticide resistance status of Ae. aegypti populations from Roraima and will help improve vector control strategies that may be applied to diverse localities under similar geographical and urban conditions.

Hybrid stars with delta matter and color–flavor locked quark phase

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.

Quark matter in compact stars

Abstract: Recently reported massive compact stars ( M ∼ 2 M ⊙ ) have provided strong constraints on the properties of the ultradense matter beyond the saturation nuclear density. Therefore, realistic quark or hybrid star models must be compatible with these observational data. Some used equations of state (EoS) describing quark matter are in general too soft and hence are not suitable to explain the stability of high compact star masses. In this work, we present the calculations of static spherically symmetric quark star structure by using an equation of state which takes into account the superconducting colour-flavour locked phase of the strange quark matter. In addition, some fundamental aspects of QCD (asymptotic freedom and confinement) are considered by means of a phenomenological description of the deconfined quark phase, the density-dependent quark mass model. We discuss the influence of the obtained quark matter equation of state on the mass-radius relationship of quark stars. Massive quark stars are found due to the stiffness of the equation of state, when reasonable values of the superconducting gap, taken as a free parameter, are used.

Myxomycetes de Florianópolis (Santa Catarina - Brasil)

Abstract: A survey on Myxomycetes was made in the woods of Lagoa do Peri and Lagoa da Conceicao in 1990, considering the absence of reports of this kind for the city of Florianopolis, when the following species were registered: Lycogala exiguum Morg. (Enteridiaceae); Cribraria languescem Rex, C. vulgaris Schr. (Cribrariaceae); Arcyria cinerea (Bull.) Pers. Hemitrichia serpula (Scop.) Rost., H. calyculata (Speg.) Fair and Hemitrichia sp (Trichiaceae); Stemonitis fusca Roth, and S. smithii Macbr. (Stemonitaceae). Exicates are deposited at the herbarium UFP. Lycogala exiguum is noted for the first time in the state of Santa Catarina, Cribraria languescem in the South and Cribraria vulgaris in Brazil. The survey raises up the number of registers refered to the state of Santa Catarina to 47 species. A review of the studies on this group of organisms in Santa Catarina is given as well as the area where each species occur in this state and in different regions of Brazil.