Federal University of Rio Grande do Norte

Natal, Brazil

The Federal University of Rio Grande do Norte is a public Brazilian university funded by the Brazilian federal government, located in the city of Natal, Rio Grande do Norte, Brazil.Formally established on December 18, 1960, it includes 60 departments providing over 70 different undergraduate courses, as well as a number of graduate programs.UFRN is the top ranked university in the state of Rio Grande do Norte, and one of the best among universities from all over the country according to 2012 league tables. Wikipedia.

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News Article | April 17, 2017
Site: www.newscientist.com

It tastes foul and makes people vomit. But ayahuasca, a hallucinogenic concoction that has been drunk in South America for centuries in religious rituals, may help people with depression that is resistant to antidepressants. Tourists are increasingly trying ayahuasca during holidays to countries such as Brazil and Peru, where the psychedelic drug is legal. Now the world’s first randomised clinical trial of ayahuasca for treating depression has found that it can rapidly improve mood. The trial, which took place in Brazil, involved administering a single dose to 14 people with treatment-resistant depression, while 15 people with the same condition received a placebo drink. A week later, those given ayahuasca showed dramatic improvements, with their mood shifting from severe to mild on a standard scale of depression. “The main evidence is that the antidepressant effect of ayahuasca is superior to the placebo effect,” says Dráulio de Araújo of the Brain Institute at the Federal University of Rio Grande do Norte in Natal, who led the trial. Shamans traditionally prepare the bitter, deep-brown brew of ayahuasca using two plants native to South America. The first, Psychotria viridis, is packed with the mind-altering compound dimetheyltryptamine (DMT). The second, the ayahuasca vine (Banisteriopsis caapi), contains substances that stop DMT from being broken down before it crosses the gut and reaches the brain. To fool placebo recipients into thinking they were getting the real thing, de Araújo and his team concocted an equally foul tasting brown-coloured drink. They also carefully selected participants who had never tried ayahuasca or other psychedelic drugs before. A day before their dose, the participants filled in standard questionnaires to rate their depression. The next day, they spent 8 hours in a quiet, supervised environment, where they received either the placebo or the potion, which produces hallucinogenic effects for around 4 hours. They then repeated filling in the questionnaires one, two and seven days later. Both groups reported substantial improvements one and two days after the treatment, with placebo scores often as high as those of people who had taken the drug. In trials of new antidepressant drugs, it is common for as many as 40 per cent of participants to respond positively to placebos, says de Araújo. But a week into this trial, 64 per cent of people who had taken ayahuasca felt the severity of their depression reduce by 50 per cent or more. This was true for only 27 per cent of those who drank the placebo. “The findings suggest a rapid antidepressant benefit for ayahuasca, at least for the short term,” says David Mischoulon of Massachusetts General Hospital in Boston. “But we need studies that follow patients for longer periods to see whether these effects are sustained.” “There is clearly potential to explore further how this most ancient of plant medicines may have a salutary effect in modern treatment settings, particularly in patients who haven’t responded well to conventional treatments,” says Charles Grob at the University of California, Los Angeles. If the finding holds up in longer studies, it could provide a valuable new tool for helping people with treatment-resistant depression. An estimated 350 million people worldwide experience depression, and between a third to a half of them don’t improve when given standard antidepressants. Ayahuasca isn’t the only psychedelic drug being investigated as a potential treatment for depression. Researchers have also seen some benefits with ketamine and psilocybin, extracted from magic mushrooms, although psilocybin is yet to be tested against a placebo.

Tehovnik E.J.,Federal University of Rio Grande do Norte | Slocum W.M.,Massachusetts Institute of Technology
Neuroscience and Biobehavioral Reviews | Year: 2013

We assess what monkeys see during electrical stimulation of primary visual cortex (area V1) and relate the findings to visual percepts evoked electrically from human V1. Discussed are: (1) the electrical, cytoarchitectonic, and visuo-behavioural factors that affect the ability of monkeys to detect currents in V1; (2) the methods used to ascertain what monkeys see when electrical stimulation is delivered to V1; (3) a corticofugal mechanism for the induction of visual percepts; and (4) the quantity of information transferred to V1 by electrical stimulation. Experiments are proposed that should advance our understanding of how electrical stimulation affects macaque and human V1. This work contributes to the development of a cortical visual prosthesis for the blind. We dedicate this work to the late Robert W. Doty. © 2013 Elsevier Ltd.

Sanders H.,Brandeis University | Renno-Costa C.,Federal University of Rio Grande do Norte | Idiart M.,Federal University of Rio Grande do Sul | Lisman J.,Brandeis University
Trends in Neurosciences | Year: 2015

Much has been learned about the hippocampal/entorhinal system, but an overview of how its parts work in an integrated way is lacking. One question regards the function of entorhinal grid cells. We propose here that their fundamental function is to provide a coordinate system for producing mind-travel in the hippocampus, a process that accesses associations with upcoming positions. We further propose that mind-travel occurs during the second half of each theta cycle. By contrast, the first half of each theta cycle is devoted to computing current position using sensory information from the lateral entorhinal cortex (LEC) and path integration information from the medial entorhinal cortex (MEC). This model explains why MEC lesions can abolish hippocampal phase precession but not place fields. © 2015 Elsevier Ltd.

Pupe S.,Uppsala University | Pupe S.,Federal University of Rio Grande do Norte | Wallen-Mackenzie A.,Uppsala University
Trends in Neurosciences | Year: 2015

The selectivity of optogenetics commonly relies on genetic promoters to manipulate specific populations of neurons through the use of Cre-driver lines. All studies performed in the ventral tegmental area (VTA) so far have utilized promoters present in groups of cells that release dopamine (DA), GABA, or glutamate. However, neurons that co-release neurotransmitters and variabilities within groups of neurons that release the same neurotransmitter present challenges when evaluating the results. Further complexity is introduced by ectopic expression patterns often occurring in transgenic Credrivers. New perspectives could be unfolded by identifying and selecting different types of promoter for driving the Cre recombinase. Here, we discuss some promising candidates and highlight the advantages or disadvantages of different methods for creating novel transgenic lines. © 2015 Elsevier Ltd.

Sequerra E.B.,Federal University of Rio Grande do Norte
Frontiers in Cellular Neuroscience | Year: 2014

The adult mammalian brain harbors a population of cells around their lateral ventricles capable of giving rise to new neurons throughout life. The so-called subventricular zone (SVZ) is a heterogeneous germinative niche in regard to the neuronal types it generates. SVZ progenitors give rise to different olfactory bulb (OB) interneuron types in accordance to their position along the ventricles. Here, I review data showing the difference between progenitors located along different parts of the SVZ axes and ages. I also discuss possible mechanisms for the origin of this diversity. © 2014 Sequerra.

Brillas E.,University of Barcelona | Martinez-Huitle C.A.,Federal University of Rio Grande do Norte
Applied Catalysis B: Environmental | Year: 2015

As the environment preservation gradually becomes a matter of major social concern and more strict legislation is being imposed on effluent discharge, more effective processes are required to deal with non-readily biodegradable and toxic pollutants. Synthetic organic dyes in industrial effluents cannot be destroyed in conventional wastewater treatment and consequently, an urgent challenge is the development of new environmentally benign technologies able to mineralize completely these non-biodegradable compounds. This review aims to increase the knowledge on the electrochemical methods used at lab and pilot plant scale to decontaminate synthetic and real effluents containing dyes, considering the period from 2009 to 2013, as an update of our previous review up to 2008. Fundamentals and main applications of electrochemical advanced oxidation processes and the other electrochemical approaches are described. Typical methods such as electrocoagulation, electrochemical reduction, electrochemical oxidation and indirect electro-oxidation with active chlorine species are discussed. Recent advances on electrocatalysis related to the nature of anode material to generate strong heterogeneous OH as mediated oxidant of dyes in electrochemical oxidation are extensively examined. The fast destruction of dyestuffs mediated with electrogenerated active chlorine is analyzed. Electro-Fenton and photo-assisted electrochemical methods like photoelectrocatalysis and photoelectro-Fenton, which destroy dyes by heterogeneous OH and/or homogeneous OH produced in the solution bulk, are described. Current advantages of the exposition of effluents to sunlight in the emerging photo-assisted procedures of solar photoelectrocatalysis and solar photoelectro-Fenton are detailed. The characteristics of novel combined methods involving photocatalysis, adsorption, nanofiltration, microwaves and ultrasounds among others and the use of microbial fuel cells are finally discussed. © 2014 Elsevier B.V.

Fichet S.,Federal University of Rio Grande do Norte
Nuclear Physics B | Year: 2014

We present a technique to determine the scale of New Physics (NP) compatible with any set of data, relying on well-defined credibility intervals. Our approach relies on the statistical view of the effective field theory capturing New Physics at low energy. We introduce formally the notion of testable NP and show that it ensures integrability of the posterior distribution. We apply our method to the Standard Model Higgs sector in light of recent LHC data, considering two generic scenarios. In the scenario of democratic higher-dimensional operators generated at one-loop, we find the testable NP scale to lie within [10, 260] TeV at 95% Bayesian credibility level. In the scenario of loop-suppressed field strength-Higgs operators, the testable NP scale is within [28, 1200] TeV at 95% Bayesian credibility level. More specific UV models are necessary to allow lower values of the NP scale. © 2014 The Author.

Ribeiro S.,Federal University of Rio Grande do Norte
Pflugers Archiv European Journal of Physiology | Year: 2012

While there is ample agreement that the cognitive role of sleep is explained by sleep-dependent synaptic changes, consensus is yet to be established as to the nature of these changes. Some researchers believe that sleep promotes global synaptic downscaling, leading to a non-Hebbian reset of synaptic weights that is putatively necessary for the acquisition of new memories during ensuing waking. Other investigators propose that sleep also triggers experience-dependent, Hebbian synaptic upscaling able to consolidate recently acquired memories. Here, I review the molecular and physiological evidence supporting these views, with an emphasis on the calcium signaling pathway. I argue that the available data are consistent with sleep promoting experience-dependent synaptic embossing, understood as the simultaneous non-Hebbian downscaling and Hebbian upscaling of separate but complementary sets of synapses, heterogeneously activated at the time of memory encoding and therefore differentially affected by sleep. © 2011 The Author(s).

Bedregal B.C.,Federal University of Rio Grande do Norte
Fuzzy Sets and Systems | Year: 2010

There exist infinitely many ways to extend the classical propositional connectives to the set [0,1], preserving their behaviors in the extremes 0 and 1 exactly as in the classical logic. However, it is a consensus that this issue is not sufficient, and, therefore, these extensions must also preserve some minimal logical properties of the classical connectives. The notions of t-norms, t-conorms, fuzzy negations and fuzzy implications taking these considerations into account. In previous works, the author, joint with other colleagues, generalizes these notions to the set U={[a,b]0≤a≤b≤1, providing canonical constructions to obtain, for example, interval t-norms that are the best interval representations of t-norms. In this paper, we consider the notion of interval fuzzy negation and generalize, in a natural way, several notions related with fuzzy negations, such as the ones of equilibrium point and negation-preserving automorphism. We show that the main properties of these notions are preserved in those generalizations. © 2010 Elsevier B.V. All rights reserved.

Batista R.C.,Federal University of Rio Grande do Norte
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2014

We show that in clustering dark energy models the growth index of linear matter perturbations, γ, can be much lower than in ΛCDM or smooth quintessence models and presents a strong variation with redshift. We find that the impact of dark energy perturbations on γ is enhanced if the dark energy equation of state has a large and rapid decay at low redshift. We study four different models with these features and show that we may have 0.33<γ(z)<0.48 at 0

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