Toxicity of the Herbicide Atrazine: Effects on Lipid Peroxidation and Activities of Antioxidant Enzymes in the Freshwater Fish Channa Punctatus (Bloch)

The present study was undertaken to evaluate the toxicity and effects of a commercial formulation of the herbicide atrazine (Rasayanzine) on lipid peroxidation and antioxidant enzyme system in the freshwater air breathing fish Channa punctatus. The 12, 24, 48, 72 and 96 h LC50 of atrazine, calculated by probit analysis, were determined to be 77.091, 64.053, 49.100, 44.412 and 42.381 mg·L−1, respectively, in a semi static system with significant difference (p < 0.05) in LC10–90 values obtained for different times of exposure. In addition to concentration and time dependent decrease in mortality rate, stress signs in the form of behavioral changes were also observed in response to the test chemical. In fish exposed for 15 days to different sublethal concentrations of the herbicide (1/4 LC50 = ∼10.600 mg·L−1, 1/8 LC50 = ∼5.300 mg·L−1 and 1/10 LC50 = ∼4.238 mg·L−1) induction of oxidative stress in the liver was evidence by increased lipid peroxidation levels. The antioxidants superoxide dismutase (SOD), catalase (CAT) and glutathione reductase (GR) responded positively in a concentration dependent pattern, thus, suggesting the use of these antioxidants as potential biomarkers of toxicity associated with contaminations exposure in freshwater fishes

Soft Power, Hard Aspirations: the Shifting Role of Power in Brazilian Foreign Policy

Journalists and policy analysts have highlighted the emergence of Brazil as a regional power. However, little attention has been paid to its foreign policy strategies. Brazil's rise to prominence in world politics represents the historical culmination of a foreign policy featuring two main strategies – persuasion and consensus building – both of which emphasise the use of soft power. We analyse four current foreign policy initiatives: the campaign for a permanent seat on the UNSC; the development of a nuclear submarine; Brazil's leadership of the UN peacekeeping mission in Haiti; and government support for Brazilian multinationals. We suggest a growing tension between these initiatives and the two strategies identified above. These initiatives reflect the view current among some policymakers that if Brazil is to rise as a global power it must play by the rules of great power politics