Species richness and beta-diversity of aquatic macrophytes assemblages in three floodplain tropical lagoons: evaluating the effects of sampling size and depth gradients

Using aquatic macrophyte data gathered in three lagoons of the Paraná River floodplain we showed a strong effect of sample size on species richness. Incidence-based species richness estimators (Chao 2, jackknife 1, jackknife 2, incidence-based coverage estimator and bootstrap) were compared to evaluate their performance in estimating the species richness throughout transect sampling rnethod. Our results suggest that the best estimate of the species richness was gave by jackknife 2 estimator. Nevertheless, the transect sampling design was considered inappropriate to estimate aquatic macrophytes species richness. Depth gradient was not a good predictor of the species richness and species turnover (beta diversity). The dynamics of these environments, subject to high water-level fluctuation prevents the formation and permanence of a clear floristic depth-related gradient

Análise de logs do sistema Agritempo por meio do log do PHPNuke e WebAlizer.

O foco deste trabalho é a análise dos logs do sistema Agritempo, um sistema de monitoramento agrometeorológico que disponibiliza informações meteorológicas e agrometeorológicas de diferentes regiões brasileiras gratuitamente na internet3. O Agritempo possui um amplo público-alvo: produtores, extensionistas, consultores, agentes do governo, estudantes e professores universitários, além da iniciativa privada

Gauge Invariant Effective Potential for Abelian Maxwell-Chern-Simons Systems

We investigate the effective potential for Abelian Maxwell--Chern--Simons systems. The calculations follow an alternate approach, recently proposed as a gauge invariant formulation of the effective potential, constructed in terms of a gauge invariant order parameter. We compare the results with another investigation, obtained within a standard route of calculating the effective potential.Comment: 10 pages. Revtex. To appear in Phys. Rev.

Gauge Invariance in Chern-Simons Systems

We show explicitly that the question of gauge invariance of the effective potential in standard scalar electrodynamics remains unchanged despite the introduction of the Chern-Simons term. The result does not depend on the presence of the Maxwell term in the Chern-Simons territory.Comment: 10 pages, Plain Tex, DF/UFPB-14/9

Exploring the mechanisms of graphene oxide toxicity to zebrafish embryo.

Many applications of graphene oxide (GO) are still in the research phase, but its promising uses have raised concerns about their risks to human health and the environment. Environmental factors, as the presence of humic substances in aquatic environment, can affect nanomaterials behavior and its toxicological effects. A previous study of our group revealed that the exposure of zebrafish embryos to GO is related to a reduction in total body length and in acetylcholinesterase activity. Thus, the aim of this study was to investigate the implications of GO exposure in muscular development and acetylcholinesterase expression. Zebrafish embryos (n=48/group) were exposed to GO (100 mg/L) in the presence or absence of humic acid (HA, 20 mg/L) during 5 days. Larvae were not feed during the experiment and were exposed under a 14/10 h light/dark cycle, 26 ± 1oC. The mortality in all groups was below 10% and no malformation was observed. At the end of the experiment, alive larvae were fixed with PFA 4% to evaluate its muscular morphology (confocal microscopy, SHG technique) or frozen in liquid nitrogen to perform RT-PCR analysis (AchE expression). Measurements of sarcomere and somite length were performed. No change in muscular tissue was observed, neither differences in AchE expression among groups were detected. So, further experiments have to be performed to clarify the mechanisms of graphene toxicity. FAPESP grants 2014/01995-9, 2014/12891-0, 2014/15640-8

Efeito de doses de calcário no desenvolvimento de plantas jovens de gravioleira e de aceroleira em Latossolo amarelo barro argilo-arenoso.

Publicado também: FRAZÃO, D. A. C.; HOMMA, A. K. O; VIÉGAS, I. de J. M. (Ed.). Contribuição ao desenvolvimento da fruticultura na Amazônia. Belém, PA: Embrapa Amazônia Oriental, 2006. p. 549-555