Biological tolerance and sublethal effects in Ucides cordatus (Linnaeus, 1763) fed by contaminated leaves

Trabajo presentado en la SETAC Latin America 12th Biennial Meeting ("Bridging the Gap between Science and Governance"), celebrada en Sao Paulo del 7 al 10 de septiembre de 2017.Crustaceans may develop biological tolerance when exposed to contaminantion over time, resulting from an adaptation achieved during their life or by genetic selection. Aquatic toxicity occurs through direct absorption of chemicals present in water, sediment or by feeding. In the contaminated mangroves of Cubatão (SP), there are records that the leaves of Rhizophora mangle have high rates of pollutants. These leaves are the main source of food to the Uçá-Crab (Ucides cordatus), a species considered sentinel of this ecosystem,. There are some evidences that U. cordatus has developed biological resistance to the main contaminants present in the mangroves of Cubatão. The objective of the study was to assess if the crabs that live in this contaminated mangrove have a higher biological tolerance comparatively to animals living in a pristine area (Jureia-Itatins). Ninety specimens from Cubatão (CUB) and ESEC Juréia-Itatins (JUR: pristine mangrove) were fed with leavesof R. mangle for 43 days (15 of acclimation: animals fed with uncontaminated leaves). The ex-situ experiment was divided in three treatments: Control (crabs from Juréia fed with uncontaminated leaves), CUB and JUR (crabs from Cubatão and Juréia fed with contaminated leaves, respectively). At seven-day intervals, the genotoxicity (Micronucleus Assay) and cytotoxicity (Neutral Red Assay) were evaluated (T-0, T- 7, T-14, T-21 and T-28). The genetic and physiological effects observed in animals from CUB and JUR treatments were statistically different from those belonging to the Control right after the first week of experiment (T-7) and remained significant throughout the period of 21 days. The physiological effects observed in the animals from CUB and JUR showed no differences during the whole experiment. In relation to genotoxicity, crabs from JUR showed higher effect recorded after 14 days of feeding, remaining stable after this period. However, the animals from CUB showed a significant temporal decrease in the frequency of micronucleated cells, possibly due to the biological genetic adaptation to contaminants found in the leaves. In conclusion, the tolerance and adaptation capacity may vary according to the level of organization analyzed and, possibly, the animals resident in the mangroves of Cubatão have developed genetic mechanisms of tolerance to the main contaminants of this region.N

A review on camel brucellosis: a zoonosis sustained by ignorance and indifference

Sediment quality from Paranagua Estuarine System (PES), a highly important port and ecological zone, was evaluated by assessing three lines of evidence: (1) sediment physical-chemical characteristics; (2) sediment toxicity (elutriates, sediment-water interface, and whole sediment); and (3) benthic community structure. Results revealed a gradient of increasing degradation of sediments (i.e. higher concentrations of trace metals, higher toxicity, and impoverishment of benthic community structure) towards inner PES. Data integration by principal component analysis (PCA) showed positive correlation between some contaminants (mainly As, Cr, Ni, and Pb) and toxicity in samples collected from stations located in upper estuary and one station placed away from contamination sources. Benthic community structure seems to be affected by both pollution and natural fine characteristics of the sediments, which reinforces the importance of a weight-of-evidence approach to evaluate sediments of PES. (C) 2008 Elsevier Inc. All rights reserved.CEM/UFPRCEM/UFPRCAPES/MEC-DGU[099/06]MEC-DGUCoordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)CAPES/MEC-DGU[3238/06-7]MEC-DGUCoordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)MEC-DGUCoordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)CAPES/MEC-DGU[3239/06-3]MEC-DGUCoordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)CAPES/MEC-DGU[2005-0100-PC]Spanish Ministry of Education Project[CTM2005-07282-C03-C01/TECNO]Spanish Ministry of Education Projec

Circuito de alimentação de semicondutores colocados a potenciais elevados num gerador de Marx

Dissertação de mestrado para obtenção do grau de Mestre em Engenharia Eletrotécnica – ramo Automação e Eletrónica IndustrialNesta dissertação foi desenvolvido um conversor ressonante LC série com um transformador, composto por um primário e quatro secundários independentes para alimentação dos circuitos de comando (drivers) dos estágios de um gerador de Marx, que se encontram a potenciais elevados. Este conversor foi simulado e ensaiado experimentalmente. A frequência de comutação do conversor encontra-se perto da frequência de ressonância com o objetivo de diminuir as perdas por comutação e consequentemente transferindo o máximo de energia possível. Foi feita uma análise de todos os elementos constituintes deste circuito e seu funcionamento em vários regimes. Também são apresentadas outras topologias que são usadas para alimentar os drivers do gerador de Marx, tais como o bootstrap, o inversor com transformador e secundários independentes, e o inversor com transformador e secundários em cascata. Demonstra-se o dimensionamento e simulação do circuito, em que a sua análise pode ser usada posteriormente para diferentes números de estágios. Os ensaios experimentais foram feitos com variações de carga nos drivers, e com a aplicação de uma condição adversa no driver de um estágio do gerador de Marx.In this master thesis a LC series resonant converter with transformer was developed, composed by one primary winding and four independent secondary windings to supplying drivers stages of Marx generator, that are at floating potentials. This converter has been simulated and experimentally tested. The switching frequency of the converter is close to the resonant frequency in order to reduce the switching losses and therefore transferring as much energy as possible. An analysis was made of all elements of this circuit and their operation in various regimes. Other topologies that are used to supply Marx generator drivers are also presented, such as the bootstrap, inverter with independent transformer and inverter with transformer and cascade secondary. It is shown the design and simulation of the circuit, where its analysis can be used later for different numbers of stages. The experimental tests were done with load variations on the drivers, and with the application of an adverse condition on the one stage driver of the Marx generator.N/

Ecological relevance of Sentinels' biomarker responses: A multi-level approach

In response to the need for more sensitive and rapid indicators of environmental quality, sublethal effects on the lowest levels of biological organization have been investigated. The ecological relevance of these responses assumes a prevailing role to assure effectiveness as indicator of ecological status. This study aimed to investigate the linkages between biomarker responses of caged bivalves and descriptive parameters of macrobenthic community structure. For this purpose a multi-level environmental assessment of marine and estuarine zones was performed in São Paulo coast, Brazil. Multivariate analysis was applied to identify linkages between biological responses and ecological indices, as well as to characterizing the studied stations. Individuals of the marine mussel Perna perna caged along Santos Bay showed signs of oxidative stress, lysosomal membrane destabilization, histological alterations and reduced embryonic development. The estuarine oyster Crassostrea rhizophorae caged along Santos Port Channel showed alterations on biotransformation enzymes and antioxidant system, DNA damage and lysosomal membrane destabilization. The benthic community analysis showed reduced richness and diversity in the same areas of the Santos bay and estuary where biomarker responses were altered. Our results revealed that xenobiotics are inducing physiological stress, which may lead to changes of the benthic community structure and deterioration of the ecological status over time. Integrating biomarker responses and ecological indexes improved certainty that alterations found at community level could be related to xenobiotic as stressors, which was very useful to improve the discriminatory power of the environmental assessment.CAPES/MECD-DGU # 099/06CAPES- BEX2492/08-03CAPES - BEX2300/08-7FAPESP - 98/00808-6CNPq - 308649/2011-7CAPES PAEX 1155-13-