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.

Rice defense responses to Bipolaris oryzae mediated by a strobilurin fungicide

Abstract: Strobilurins, also known as quinone outside inhibitors (QoIs), are one of the most important fungicide groups for controlling plant diseases. In addition, they can prime plants for enhanced defense against pathogen attack. Here, detailed biochemical and microscopic analyses were performed to investigate whether azoxystrobin (Az) could enhance defense responses to Bipolaris oryzae, the cause of brown spot of rice. Fungal infection increased the activity of all defense enzymes regardless of fungicide treatment. Az-sprayed plants displayed higher activities of β-1,3-glucanase, peroxidase, polyphenol oxidase (PPO) and lipoxygenase (LOX) in the absence of B. oryzae inoculation and of phenylalanine ammonia-lyase, PPO and LOX at 24 h after inoculation (hai) with B. oryzae compared to the control plants. Concentrations of total soluble phenols at 144 hai were higher in the Az-sprayed plants relative to their non-treated counterparts. Concentrations of lignin-thioglycolic acid derivatives were increased following fungal infection in the control plants. Hyphae from B. oryzae colonized bulliform, bundle sheath, epidermal, guard, mesophyll and vascular bundle cells besides intercellular spaces, but fewer and smaller fungal cells were noticed in the Az-sprayed than in the control plants. Therefore, although Az transiently reprogrammed activities of some defense enzymes, its fungicidal activity appears to have played a major role in reducing B. oryzae infection.

Persistent chikungunya arthritis in Roraima, Brazil

Abstract: The Amazon region of Brazil experienced a large epidemic of East Central South African (ECSA) chikungunya virus (CHIKV) in 2017 and continuous transmission of CHIKV persists. The impact of chronic arthritis caused by ECSA CHIKV is unknown. The study aim was to describe the duration, severity, and characteristics of CHIKV arthritis in Roraima, Brazil, in comparison with local controls to further understand the long-term rheumatologic impact of ECSA CHIKV infection. We performed a cross-sectional analysis comparing clinical arthritis outcomes among 40 cases with chronic (> 3 months) arthritis attributed to their CHIKV disease (n = 40) with control participants who were exposed to CHIKV but did not develop chronic arthritis (n = 40), rheumatoid arthritis controls (n = 40), and healthy controls lacking CHIKV exposure and arthritis (n = 40). Our primary finding is that over 2 years post-infection, patients report moderate arthritis disease severity comparable with rheumatoid arthritis with the most significant impact on decreased quality of life from pain. These findings suggest that chronic arthritis caused by ECSA CHIKV infection has had a moderate impact in the Americas.

Morfometria e crescimento inicial de Copaifera pubiflora exposta à terra vegetal produzida em compostagem

Abstract: This research aimed to assess the emergence and initial growth of Copaifera pubiflora Benth. (copaibeira) exposed to vegetable land produced in school composting. The seeds of C. pubiflora were collected in the area of the riparian forest of Boa Vista, Roraima and classified as size (small or large) and performed the biometric characterization (length, diameter and mass of the seed). The experiment consisted of six different doses of vegetable land (0, 20, 40, 60, 80 and 100%) in sterile sand. The variables evaluated responses were: emergency percentage of seedlings, height of the aerial part, diameter of the stem and dry matter of seedlings. There was significant difference in the quality of seedlings of C. pubiflora cultivated according to the size of seeds and doses of vegetable land. Plants originating from large seeds have better quality in the measured variables. The use of vegetable land in doses greater than 20 and 40% interferes negatively in the emergence of small and large seeds of C. pubiflora, respectively. The initial growth of plants from C. pubiflora is benefited when using doses of up to 60% of vegetable land and 40% of sterile sand, for both seed sizes.

Compartimentação hidrogeológica do Sistema Aquífero Guarani na escarpa da serra geral no nordeste do RS

Abstract: The objective of this work was to evaluate the compartmentation of the Guarani Aquifer System (GAS) in the Serra Geral escarpment in the northeast of the RS. Therefore, the information of 276 tubular wells and the trace of morphostructural lineament at different scales were used, aiming to promote the delimitation of hydrogeological compartments and to evaluate their influence on the aquifer characteristics. The results were used in the elaboration of a conceptual hydrogeological model. It was observed that the variations of the top of the GAS present relations with the relief of the region. The groundwater flow follows from the highest regions towards the limits of the compartments, following, in general, the top of the GAS, with characteristics of unconfined aquifer. The specific capacity presented a great variation between the compartments, with the most productive wells located near the discharge areas of the aquifer. Regarding the hydrochemistry, it was verified little differentiation between waters, with variations occurring mainly due to the influence of local characteristics. Thus, the results obtained in this study demonstrate that, in the study area, the GAS is compartmentalized, and that this compartmentation has influence both in productivity, as well as in the top of the SAG and in the groundwater flow.