Federal University of Tocantins

Palmas, Brazil

The Universidade Federal do Tocantins is a public federal university located in the state of Tocantins, Brazil. This university has campuses located in Araguaína, Arraias, Gurupi, Miracema, Palmas, and Porto Nacional e Tocantinópolis. Wikipedia.

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Albert J.S.,University of Louisiana at Lafayette | Schoolmaster D.R.,U.S. Geological Survey | Tagliacollo V.,Federal University of Tocantins | Duke-Sylvester S.M.,University of Louisiana at Lafayette
Systematic Biology | Year: 2017

Macroevolutionary theory posits three processes leading to lineage diversification and the formation of regional biotas: dispersal (species geographic range expansion), speciation (species lineage splitting), and extinction (species lineage termination). The Theory of Island Biogeography (TIB) predicts species richness values using just two of these processes; dispersal and extinction. Yet most species on Earth live on continents or continental shelves, and the dynamics of evolutionary diversification at regional and continental scales are qualitatively different from those that govern the formation of species richness on biogeographic islands. Certain geomorphological processes operating perennially on continental platforms displace barriers to gene flow and organismal dispersal, and affect all three terms of macroevolutionary diversification. For example, uplift of a dissected landscape and river capture both merge and separate portions of adjacent areas, allowing dispersal and larger geographic ranges, vicariant speciation and smaller geographic ranges, and extinction when range sizes are subdivided below a minimum persistence threshold. The TIB also does not predictmany biogeographic and phylogenetic patterns widely observed in continentally distributed taxa, including: (i) power function-like species-area relationships; (ii) log-normal distribution of species geographic range sizes, in which most species have restricted ranges (are endemic) and few species have broad ranges (are cosmopolitan); (iii) mid-domain effects with more species toward the geographic center, and more early-branching, species-poor clades toward the geographic periphery; (iv) exponential rates of net diversification with log-linear accumulation of lineages through geological time; and (v) power function-like relationships between speciesrichness and clade diversity, in which most clades are species-poor and few clades are species-rich. Current theory does not provide a robust mechanistic framework to connect these seemingly disparate patterns. Here we present SEAMLESS (Spatially Explicit Area Model of Landscape Evolution by Simulations) that generates clade diversification by moving geographic barriers on a continuous, neutral landscape. SEAMLESS is a neutral Landscape Evolution Model (LEM) that treats species and barriers as functionally equivalent with respect to model parameters. SEAMLESS differs from other model based biogeographic methods (e.g., Lagrange, GeoSSE, BayArea, and BioGeoBEARS) by modeling properties of dispersal barriers rather than areas, and by modeling the evolution of species lineages on a continuous landscape, rather than the evolution of geographic ranges along branches of a phylogeny. SEAMLESS shows how dispersal is required to maintain species richness and avoid clade-wide extinction, demonstrates that ancestral range size does not predict species richness, and provides a unified explanation for the suite of commonly observed biogeographic and phylogenetic patterns listed above. SEAMLESS explains how a simple barrier-displacement mechanism affects lineage diversification under neutral conditions, and is advanced here toward the formulation of a general theory of continental biogeography.

This study aimed to present some double entry volumetric models developed to quantify the volume of wood in Brazil. As a case study, we used data of 180 trees-sample of Eucalyptus urophylla and Eucalyptus grandis aged 5-7 years. To evaluate the volumetric models performance, we used the following statistical criteria, standard error of the estimate, adjusted coefficient of determination, mean absolute error, sum of squared of relative errors, average of percentage error, standard deviation of the errors, determination coefficient between actual and predicted volume, square root of the average error and analysis of the distribution of residuals. We selected a volumetric model developed from the form factor equation adapted to the Gompertz's biomathematical model.

Pompeu P.S.,Federal University of Lavras | Agostinho A.A.,State University of Maringá | Pelicice F.M.,Federal University of Tocantins
River Research and Applications | Year: 2012

Most of the large rivers of South America are impounded mainly for hydropower production. The construction of fish passes has been one of the strategies adopted by Brazilian authorities and the energy sector to diminish the effects of these barriers on migratory fish communities. Despite the high investments and efforts involved, most facilities have been considered ineffective for conservation purposes. Decades of poor monitoring and the lack of specific studies have limited our knowledge on the real role of fish passes. Efficiency has been frequently defined as the proportion of fish that ascend a fish passage facility, compared to the shoal size that reaches the dam. Inspired by the notion that fishes accumulated below the dam need to migrate upstream, the quantity of fish passed upstream historically indicated successful management, as generally inferred by the fish abundance inside the fish pass. We propose a new concept for estimating fish pass efficiency for South American rivers, based on the capability of the fish pass to maintain viable populations. This broader approach is necessary because knowledge of fish habitats below and above the pass, plus the feasibility of downstream movements of eggs, larvae and adults through the reservoir and past the dam, is needed for assessing whether a fish pass is working as a conservation tool. © 2011 John Wiley & Sons, Ltd.

Pelicice F.M.,Federal University of Tocantins | Pompeu P.S.,Federal University of Lavras | Agostinho A.A.,State University of Maringá
Fish and Fisheries | Year: 2015

Most large rivers in South America are fragmented by large dams, and a common management strategy to mitigate impacts has been construction of fish passes. Recent studies, however, indicate that downstream passage of adults and young fish is nil or minimal. Better understanding of this phenomenon is needed if fishways are to provide any tangible conservation value in South America. We propose, in this article, that large reservoirs impose a different kind of barrier to migrating fish: impoundments create a diffuse gradient of hydraulic/limnological conditions that affects fish behaviour and functions as an extensive environmental filter that discourages downstream movements. To develop this idea, we characterize the barriers created by dams and reservoirs by describing their distinct nature, the effects on fish migration and potential solutions. We show, for example, that dams generally prevent upstream movements, whereas reservoirs impede mainly downstream movements. In this context, we explain how fish passes, in some instances, can partially mitigate fragmentation caused by dams, but there is no technical solution to solve the barrier effect of reservoirs. In addition, we present a body of empirical evidence that supports the theory that large reservoirs are important barriers to fish migration in South America, we offer an overview of the size of reservoirs to show that impoundments typically have large dimensions, and we discuss the significance of this theory for other regions. Based on current and proposed river regulation scenarios, we conclude that conservation of Neotropical migratory fish will be much more complicated than previously believed. © 2015 John Wiley & Sons Ltd.

Pelicice F.M.,Federal University of Tocantins | Vitule J.R.S.,Federal University of Paraná | Lima Junior D.P.,Federal University of Mato Grosso | Orsi M.L.,State University Londrina | Agostinho A.A.,State University of Maringa
Conservation Letters | Year: 2014

As Brazil undergoes rapid economic growth, short-sighted political decisions can threaten biological diversity and ecosystem services. Recently, the Brazilian Congress proposed a law to allow the rearing of nonnative fish in aquaculture cages in any hydroelectric reservoir of the country. This initiative may "naturalize by decree" some of the worst invasive species in the world (e.g., carps and tilapias) as a means of developing inland aquaculture and economy. The spread of aquaculture facilities will create opportunities for fish invasions to occur throughout the country, with the risk of damaging native biodiversity, ecosystem services, and environmental quality on a continental scale. The proposal ignores ecological theory, historical and/or empirical data concerning fish invasion, including dispersal, establishment, propagule pressure, invasiveness and invasibility, and all the negative consequences that may follow the invasion and establishment of nonnative organisms. This situation inspires reflection about the future of tropical biodiversity worldwide, particularly because Brazil, like many other developing countries, possesses a remarkable diversity of fish and other freshwater organisms yet has taken some political measures that are in conflict with important conservation issues. © 2013 Wiley Periodicals, Inc.

Dibble E.D.,Mississippi State University | Pelicice F.M.,Federal University of Tocantins
Ecology of Freshwater Fish | Year: 2010

This study investigated the effects of plant-specific habitat on the distribution of young and small adult fishes in lagoons of the Upper Paraná River floodplain, Brazil. We compared fish catch per unit effort (CPUE) and species richness and used an indirect gradient analysis to investigate fish-plant relationships within three aquatic macrophytes beds (Cabomba furcata, Eichhornia azurea, Nymphaea amazonum), and explored microhabitat influence (indexed by eight variables related to physical structure and water quality) on the structure of fish assemblages. Rarefaction analysis was used to compare fish species richness among the vegetated habitats. We captured a total of 1599 fish constituting 23 species, 7 families and 3 orders. Fish CPUE and species richness increased relative to microhabitat structure innate to the macrophytes; higher CPUE and richness were observed in C. furcata beds, a submerged aquatic macrophyte with finely dissected leaves. On the contrary, N. amazonum, a species that provides low microhabitat complexity, harbored fewer individual fish and number of species. Reproduction dynamics, hydrology and the amount of available plant-generated habitat structure (surface effect) contributed to the disproportionally high number of individuals captured during the dry season. Our data suggest that the microhabitat physical structure (e.g., edge distance, stem density and patch size) provided by macrophyte beds in the lagoons of the Upper Paraná River may play a more important role than physicochemistry (e.g., oxygen, temperature and pH) at mediating distribution patterns of small-sized fishes. © 2010 John Wiley & Sons A/S.

Franco E.T.,Federal University of Tocantins
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2015

A seesaw mechanism is presented in the neutrino sector and a new phase of CP violation (α) emerges in the interplay between the type-I and type-III seesaw schemes. This phase is inside the mixing term, and thus it cannot be rotated away in the Yukawa Lagrangian and, therefore, the heavy symmetry states cannot be in a diagonal weak basis in the broken phase. Some particular descriptions are analyzed suggesting that if the usual Yukawa couplings are suppressed, leptogenesis still occurs due to a new interacting vertex with fermion triplet T, fermion singlets N, and scalar triple, Σ, which now is included to mediate the interactions. The evaluated CP violation is enough to generate the observed matter-antimatter asymmetry even in the minimal 1N+1T case (independently of α) or in the 2N+1T approach (controlled by α). The latter introduces more CP contributions to leptogenesis due to new diagrams which are now possible even with the suppressed imaginary part of the standard Yukawa couplings and can induce the observed baryon-to-photon ratio. © 2015 American Physical Society.

de Mello C.R.,Federal University of Lavras | Viola M.R.,Federal University of Tocantins
Revista Brasileira de Ciencia do Solo | Year: 2013

Studies of heavy rainfall are of practical interest for the conservation management of natural resources such as watersheds and soil and water. The spatial distribution of these natural rainfall events allows conclusions about regions where the occurrence of heavy rain is more frequent and to estimate their magnitude for locations without rainfall data sets. Thus, the purpose of this study was to map heavy rainfall data from 177 meteorological stations, using a geostatistical approach, for Minas Gerais, identifying the most vulnerable regions in terms of the occurrence of heavy rain. The highest values were estimated for the East and Northwest regions of the state, which can be explained by the influence of the South Atlantic Converge Zone (SACZ), aside from convective rainfall events. In addition, the lowest and intermediate values were found and mapped, respectively, for the North/Northeast and Mid/ South regions of the state. For the rainfall events with longest duration, intensities were high in the Southern region, which can be explained by the more frequent cold weather fronts that induce long-lasting rains.

The aims of the present study were to describe cancer causes and risk perception, and to associate behaviors adopted for the prevention of tumors and cancer family history in individuals with suspect of hereditary cancer syndromes. A convenience sample of 51 individuals was selected from an oncogenetic counseling outpatient clinic in a university hospital in the countryside of the state of São Paulo. An instrument adapted to Brazilian culture was used. The respondents considered their own risk as being the same as the population's risk, and family history was not statistically associated with the performing of preventive exams. These findings highlight the need for intervention by health professionals, especially nurses, who may conduct health education activities for this population, which is an essential component of nursing care in oncogenetics.

De Carvalho R.L.,Federal University of Tocantins | Rosa P.F.F.,Brazilian Military Institute of Engineering
IEEE International Symposium on Industrial Electronics | Year: 2010

This work proposes an identification system for smart buildings using footstep information. Basically, the system has three modules: pre-processing, feature extraction and selection, and classification of the information. Gait frequency, spectral envelope, cepstral and mel-cepstral analysis and loudness compose the set of parameters used to identify subjects in the smart building. In order to select features, the Fisher's criterion was used. For the classification task, K-Means and K-NN algorithms were performed along with different methodologies for test and validation. Moreover, the best sets were gathered, increasing the accuracy of classification. Several experiments were performed with 15 subjects wearing 6 different footwear. The classification rates were in the range from 33.5% to 97.5%. © 2010 IEEE.

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