URI Integrated Regional University Brazil

Erechim, Brazil
Time filter
Source Type

Antunes Wilhelm E.,URI Integrated Regional University Brazil | Antunes Wilhelm E.,Federal University of Santa Maria | Ricardo Jesse C.,Federal University of Pampa | Folharini Bortolatto C.,Federal University of Santa Maria | Wayne Nogueira C.,URI Integrated Regional University Brazil
European Journal of Pharmacology | Year: 2013

The present study was designed to examine the correlations between behavioural and oxidative parameters in a quinolinic acid model of Huntington's disease in rats. The protective effect of melatonin against the excitotoxicity induced by quinolinic acid was investigated. Rats were pre-treated with melatonin (5 or 20 mg/kg) before injection of quinolinic acid (240 nmol/site; 1 μl) into their right corpora striata. The locomotor and exploratory activities as well as the circling behaviour were recorded. The elevated body swing test was also performed. After behavioural experiments, biochemical determinations were carried out. Melatonin partially protected against the increase of circling behaviour caused by quinolinic acid injection. No alteration was found in the number of crossings and rearings of animals treated with melatonin and/or quinolinic acid. Melatonin decreased the percentage of contralateral biased swings induced by quinolinic acid. Melatonin protected against the increase in reactive species and protein carbonyl levels as well as the inhibition of superoxide dismutase activity resulting from quinolinic acid injection. Melatonin was partially effective against the inhibition of striatal catalase activity and a decrease of non-protein thiol levels induced by quinolinic acid. Melatonin was not effective against the inhibition of Na +, K+ ATPase activity caused by quinolinic acid injection. There were significant correlations between circling behaviour and oxidative parameters. The antioxidant property of melatonin is involved, at least in part, in its neuroprotective effect. The results reinforce the idea that melatonin could be useful in overwhelming neurotoxicity caused by quinolinic acid, a rat model of Huntington's disease. © 2013 Elsevier B.V. All rights reserved.

Barcellos L.J.G.,University Of Passo Fundo | Volpato G.L.,São Paulo State University | Barreto R.E.,São Paulo State University | Coldebella I.,URI Integrated Regional University Brazil | Ferreira D.,Federal University of Santa Maria
Physiology and Behavior | Year: 2011

We investigated whether juveniles of the nocturnal fish jundiá (Rhamdia quelen) and the diurnal fish Nile tilapia (Oreochromis niloticus) are able to chemically communicate stress to conspecifics. Groups of 8 fish were reared in tanks under recirculated water (water exchanged among all the tanks) for each species. Fish were handled in half of the tanks (stressor fish) and whole-body cortisol concentrations were compared among handled fish, non-handled fish exposed to water from the handled fish, and non-handled control fish held with no water communication. For each treatment cortisol concentrations were determined before exposure to the stressor (basal levels) and after 1, 2, 4, 8, and 24. h. Basal levels of cortisol confirmed fish were unstressed in the beginning of the experiment. Cortisol was increased in the stressor fish 1. h after handling. Fish receiving water from the stressor fish increased cortisol levels later (2. h after the stressor fish were handled). As the isolated control group maintained cortisol levels unchanged throughout the experiment, we concluded that some chemical factor was released by the stressed fish in the water and thus stressed the conspecifics. This pattern was similar for both unrelated species, thus suggesting that this communication might have evolved earlier in fish and reinforcing the biological value of this kind of information. © 2011.

Maestri R.,URI Integrated Regional University Brazil | Marinho J.R.,URI Integrated Regional University Brazil
Acta Theriologica | Year: 2014

Rainfall is often indirectly related to the availability of resources, which in turn regulates the abundance of rodents over time. However, the direct influence of rainfall on daily activity is poorly understood, despite the fact that it likely has a great effect on small animals. Furthermore, the influence of the moon on the movement of rodents has been the subject of debate but limited to studies conducted in open areas. Based on a study using pitfall traps in a subtropical region of southern Brazil, this study aimed to investigate the effects of rainfall and the phases of the moon on the daily movements of five species of sigmodontine rodents in a Neotropical forest. Activity patterns were assessed over 130 days, and the daily rainfall and moon phase were verified. Rainfall exhibited a significant positive effect on all studied species. This reflects an increase in the movement of rodents on rainy days, which should be primarily associated with the immediate harmful effects of rain, such as a wet coat and the destruction of shelters. The five species responded differently to moon phase, with a lack of effect for three of them and a positive effect of a full moon on the activity patterns of the other two species. This increase in activity rhythm due to a full moon may indicate a benefit of clear nights for foraging, in contrast to the most common outcome, which associates the brightness of the moon with increased predation risk. © 2014 Mammal Research Institute, Polish Academy of Sciences, Białowieża, Poland.

Padilha D.L.,Federal University of Goais | Loregian A.C.,Federal University of Rio Grande do Sul | Budke J.C.,URI Integrated Regional University Brazil
Biodiversity and Conservation | Year: 2015

Testing whether biological invasions can be facilitated by habitat fragmentation can provide important insights for the study of invasion ecology. Hovenia dulcis is considered an aggressive non-native species in subtropical Atlantic forest ecosystems and following the assumptions of invasion ecology we hypothesized it would occur mainly in smaller forest remnants, which are more susceptible to edge effects compared to larger ones. In this study, we verified the relationships between H. dulcis invasion on forest remnants and the current habitat fragmentation and tested whether both occurrence and abundance of this species are driven by landscape and habitat variables. We selected 30 forest fragments in initial, middle or late successional stages and verified the occurrence and abundance of trees and saplings of H. dulcis. We evaluated spatial autocorrelation and the influence of landscape and habitat metrics on occurrence and abundance of such species and the influence of fruiting trees (adults) on the abundance of non-adult individuals. We found that H. dulcis distribution was not related to geographic distance among remnants. The occurrence of adult H. dulcis was directly associated to closed-canopy areas and remnant shape and, contrary our initial hypothesis, not related to remnant size. The occurrence of adult trees increased H. dulcis regeneration leading to higher sapling abundance. High abundance of H. dulcis saplings close to adult trees pointed out the successful colonization of recently invaded Atlantic forest remnants. We showed that this invasive tree species successfully invades closed-canopy forest fragments, which highlight undisturbed subtropical Atlantic forest habitats are as susceptible to biological invasions as disturbed ones. © 2015, Springer Science+Business Media Dordrecht.

Qualitative study that aimed at investigating concepts and practices of nursing technicians on biosecurity and its interface with biological hazards, with 20 workers developed a clinical care unit of a hospital in the interior of Rio Grande do Sul. Data were collected through interviews and systematic observation. Thematic analysis was the methodology used for data processing. The negligence of its employees on the use of individual protection equipment and work overload are risk factors for accidents with biological material. Suggested that partnerships between the actors involved in caring for the construction of healthy environments and accountability for negligence on biosecurity.

Centeno F.R.,Federal University of Rio Grande do Sul | Da Silva C.V.,URI Integrated Regional University Brazil | Franca F.H.R.,Federal University of Rio Grande do Sul
Energy Conversion and Management | Year: 2014

This paper presents a study of the effect of thermal radiation in the simulation of a turbulent, non-premixed methane-air flame. In such a problem, two aspects need to be considered for a precise evaluation of the thermal radiation: the turbulence-radiation interactions (TRI), and the local variation of the radiative properties of the participating species, which are treated here with the weighted-sum-of-gray-gases (WSGG) model based on newly obtained correlations from HITEMP2010 database. The chemical reactions rates were considered as the minimum values between the Arrhenius and Eddy Break-Up rates. A two-step global reaction mechanism was used, while the turbulence modeling was considered via standard k-É model. The source terms of the energy equation consisted of the heat generated in the chemical reaction rates as well as in the radiation exchanges. The discrete ordinates method (DOM) was employed to solve the radiative transfer equation (RTE), including the TRI. Comparisons of simulations with/without radiation (which in turn was solved with/without TRI) demonstrated that the temperature, the radiative heat source, and the wall heat flux were importantly affected by thermal radiation, while the influence on species concentrations proved to be negligible. Inclusion of thermal radiation led to results that were closer to experimental data available in the literature for the same test case considered in this paper. Inclusion of TRI improved the agreement, although in a smaller degree. The main influence of TRI was mainly on global results, such as the peak temperature and the radiant fraction. The results show the importance of thermal radiation for an accurate prediction of the thermal behavior of a combustion chamber. © 2013 Elsevier Ltd. All rights reserved.

Santos A.V.D.,URI Integrated Regional University Brazil
Computational Materials Science | Year: 2012

The theoretical prediction of compounds' properties is a desired dream by physicists, chemists and materials engineers; here we will establish a model to predict the stability of alloys, using first-principles LAPW calculations (Linearized Augmented Plane Waves) which is a APW modification (Augmented Plane Waves Method of Slater). We propose to calculate the energy of formation and cohesive energy of iridium-iron alloys and iridium-iron nitrides. In this discussion we will find a methodology that can be applied to solids with different atoms, creating a model to calculate the stability of these alloys. In our calculations we found a unit cell volume with a high increase when we changed from alloys to nitrides, thereby strongly influencing the energy of formation and cohesive energy. We also study the pressure in response to changes in the volume and the total energy of the compound, verifying that the same volume of balance was found in the minimum of cohesive energy of compounds at zero pressure. Finally, we discuss the critical pressure between ferromagnetic and non-magnetic phases, which proves to be of the same order of magnitude of some experimental and theoretical results of other systems. © 2012 Elsevier B.V. All rights reserved.

Dos Santos A.V.,URI Integrated Regional University Brazil
Solid State Communications | Year: 2011

The importance of using theoretical methods for first principles calculations to have a better understanding of new material properties gives a detailed study on the properties of the ground state. In the present paper a study was carried out on the effects of a carbon atom inserted into the Ni 3Al structure changing its crystalline FCC to a perovskite structure in the form of Ni3AlC. Initially, we show the equilibrium volume of the two composites where there is a good agreement with the experimental value. In addition, we point out a magnetic structure where we find low magnetization in the composite Ni3AlC and reveal an appreciable magnetization in the composite Ni3Al. In order to obtain the results above we used the first-principles method: the Linearized Augmented Plane Wave (LAPW) method within the Generalized Gradient Approximation (GGA). Besides, we carried out a comparison with the experimental results presented in the literature, which showed reasonable agreement between theory and experiment. © 2010 Elsevier Ltd. All rights reserved.

Van Achte, URI Integrated Regional University Brazil and Le Moine | Date: 2012-12-05

Disclosed is a method for generating a surround-channel audio signal (Mout) from a mono/stereo audio signal (Min, Sin), comprising the steps of:a) generating a first multi-channel signal (M1) by surround panning the mono/stereo audio signal (Sin);b) generating a second multi-channel signal (M2) by effect processing the mono/stereo input signal (Min, Sin) so that the rear signals comprise at least reverberation of the mono/stereo audio signals;c) mixing the corresponding signals of the first multi-channel signal (M1) and the second multi-channel signal (M2), thereby forming the surround-channel audio signal (Mout).

In this paper the lifestyle of the large Balaton-Lasinja/Furchenstich and Boleráz/Baden settlement, Balatonocombining double acute accentszöd-Temetocombining double acute accenti ducombining double acute accentlocombining double acute accent was investigated, in the respect of possible common ceramic forms, technology, tradition, food-products and consumption in the period of Middle and Late Copper Age. Archaeometrical investigation of the same subject is presented below in the article of Gherdán et al., same volume. On the base of the excavation data, the water-logged settlement of Balatonocombining double acute accentszöd- Temetocombining double acute accenti ducombining double acute accentlocombining double acute accent first time was dated in the Middle Copper Age, Balaton-Lasinja/Furchenastich period. In the pottery we can find many similarities to the Late Copper Age Boleráz/Baden period (e.g. the same clay-mine used, pottery tempered with grog, same burning method, polished pottery surface, dark color, dotted and channeled decoration, birch-bark tar using on the inner or outer surface, handles fixed by joint, appaerance liquid-storage vessels with handle: e.g. jugs, amphorae). We can notice some differences also: in the Middle Copper Age the potters built the pottery from bands, in the Late Copper Age the potters worked also with patches. There are differences in the fixing of the bottom to the vessel-side. Because of the closest analogies among the vessel-forms and building technique, and the mixed features and finds on the same site we suggest the interaction of this two periods. The possible synchronism happened around 3700-3500 cal BC. The practice to make pots in the Boleráz and the Baden periods was the same, but among the forms we can find many differences. Both population used the same clay pits, technology and vegetal decoration system. The organic residues on the pots indicated fixed, common or familiar / household cooking places and culture: food prepared mainly from animal products. Both cultures were basically stock-breeding communities, and they lived on extensive, sparse settlements. The Boleráz and the Baden independent folk fused at the site among 3300-3100 cal BC. © by the author(s).

Loading URI Integrated Regional University Brazil collaborators
Loading URI Integrated Regional University Brazil collaborators