A New Indirect Electroanalytical Method to Monitor the Contamination of Natural Waters with 4-Nitrophenol Using Multiwall Carbon Nanotubes

The electrochemical detection of the hazardous pollutant 4-nitrophenol (4-NP) at low potentials, in order to avoid matrix interferences, is an important research challenge. This study describes the development, electrochemical characterization and utilization of a multiwall carbon nanotube (MWCNT) film electrode for the quantitative determination of 4-NP in natural water. Electrochemical impedence spectroscopy measurements showed that the modified surface exhibits a decrease of ca. 13 times in the charge transfer resistance when compared with a bare glassy carbon (GC) surface. Voltammetric experiments showed the possibility to oxidize a hydroxylamine layer (produced by the electrochemical reduction of 4-NP on the GC/MWNCT surface) in a potential region which is approximately 700 mV less positive than that needed to oxidize 4-NP, thus minimizing the interference of matrix components. The limit of detection for 4-NP obtained using square-wave voltammetry (0.12 mu mol L(-1)) was lower than the value advised by EPA. A natural water sample from a dam located in Sao Carlos (Brazil) was spiked with 4-NP and analyzed by the standard addition method using thee GC/MWCNT electrode, without any further purification step. the recovery procedure yielded a value of 96.5% for such sample, thus confirming the suitability of the developed method to determine 4-NP in natural water samples. The electrochemical determination was compared with that obtained by HPLC with UV-vis detection.

The Evolution of a Responsibility to Protect in Africa : The African Unions Emerging Peace and Security Regime

The thesis focuses on, and tries to evaluate, the role that the African Union (AU) plays in protecting the peace and security on the African continent. The thesis takes an interdisciplinary approach to the topic by both utilizing international relations and international law theories. The two disciplines are combined in an attempt to understand the evolution of the AU’s commitment to the pragmatist doctrine: responsibility to protect (R2P). The AU charter is considered to be the first international law document to cover R2P as it allows the AU to interfere in the internal affairs of its member states. The R2P doctrine was evolved around the notion of a need to arrive at a consensus in regard to the right to intervene in the face of humanitarian emergencies. A part of the post-Cold War shift in UN behaviour has been to support local solutions to local problems. Hereby the UN acts in collaboration with regional organizations, such as the AU, to achieve the shared aspirations to maintain international peace and security without getting directly involved on the ground. The R2P takes a more holistic and long-term approach to interventions by including an awareness of the need to address the root causes of the crisis in order to prevent future resurrections of conflicts. The doctrine also acknowledges the responsibility of the international community and the intervening parties to actively participate in the rebuilding of the post-conflict state. This requires sustained and well planned support to ensure the development of a stable society.While the AU is committed to implementing R2P, many of the AU’s members are struggling, both ideologically and practically, to uphold the foundations on which legitimate intervention rests, such as the protection of human rights and good governance. The fact that many members are also among the poorest countries in the world adds to the challenges facing the AU. A lack of human and material resources leads to a situation where few countries are willing, or able, to support a long-term commitment to humanitarian interventions. Bad planning and unclear mandates also limit the effectiveness of the interventions. This leaves the AU strongly dependent on regional powerbrokers such as Nigeria and South Africa, which in itself creates new problems in regard to the motivations behind interventions. The current AU charter does not provide sufficient checks and balances to ensure that national interests are not furthered through humanitarian interventions. The lack of resources within the AU also generates worries over what pressure foreign nations and other international actors apply through donor funding. It is impossible for the principle of “local solutions for local problems? to gain ground while this donor conditionality exists.The future of the AU peace and security regime is not established since it still is a work in progress. The direction that these developments will take depends on a wide verity of factors, many of which are beyond the immediate control of the AU.

Dwelling in possibility: aestheticizing identity in African American women's fiction

African American women writers define aesthetics through their negotiation of identity in the politicized loci of space, place and voice. In the balkanization of such issues of voice and space, we can see the ways that the emergent selfis embodied and aestheticized in literature. To do so creates a more tactile and "artfull" representation of the self rather than a representation of identity as a mere abstract concept. To use written language to express the self is to carry processes of selfdefinition for black women into the realm of creative production. For women, especially black women, who are a politically and socially compromised element of society, the written word is a way of expressing the politically and the socially critical voice that is suppressed in other forums of expression. Using theories on "writing in difference" as a skeleton key, this project seeks to outline some of the ways that black women writers use aesthetic elements in their art to express the potential for self-examination, discovery, and emancipation.

May 2000: Copyright: Stain the Waters Clear

http://digitalcommons.winthrop.edu/deanscorner/1009/thumbnail.jpg

Sexual blinging of women : Alice Walker's african character tashi and issue of female genital cutting

This thesis provides a reading of the different forms of representation that can be attributed to the character Tashi, the protagonist of the novel Possessing the Secret of Joy (1992), written by the African American writer Alice Walker. Before this work Tashi had already appeared in two previous novels by Walker, first, in The Color Purple (1982) and then, as a mention, in The Temple of My Familiar (1989). With Tashi, the author introduces the issue of female circumcision, a ritual Tashi submits herself to at the beginning of her adult life. The focus of observation lies in the ways in which the author’s anger is transformed into a means of creative representation. Walker uses her novel Possessing the Secret of Joy openly as a political instrument so that the expression “female mutilation” (term used by the author) receives ample attention from the media and critics in general. The aim of this investigation is to evaluate to what extent Walker’s social engagement contributes to the development of her work and to what extent it undermines it. For the analysis of the different issues related to “female genital cutting”, the term I use in this thesis, the works of feminist critics and writers such as Ellen Gruenbaum, Lightfoot-Klein, Nancy Hartsock, Linda Nicholson, Efrat Tseëlon and the Egyptian writer and doctor Nawal El Saadawi will be consulted. I hope that this thesis can contribute as an observation about Alice Walker’s use of her social engagement in the creation of her fictional world.

Brachyuran soft-bottom assemblage from marine shallow waters in the southeastern Brazilian littoral.

The present investigation examined the assemblages of brachyuran crabs in three bays of southeastern So Paulo State, analyzing the numbers of species and individuals, biomass, and diversity. The crabs were collected monthly in Ubatumirim, Ubatuba, and Mar Virado bays in the Ubatuba region over 2 years (1998 and 1999). In each bay, six tows were made from a fishing boat. A total of 39,820 specimens, representing 11 super families, 39 genera, and 65 species of brachyurans, were obtained. The mean number of specimens and biomass varied seasonally, which can be mainly related with the population tendencies of two dominant species in the area (Callinectes ornatus and Hepatus pudibundus). The highest numbers of individuals and species were found in Ubatuba Bay, followed by Ubatumirim and Mar Virado. The highest diversity index was estimated for Ubatumirim (H' = 2.44), followed by Ubatuba (H' = 2.37) and Mar Virado (H' = 1.86). In general, the coastal region supported high abundance and species richness concerning brachyurans, with high diversity indices, probably because of its more-heterogeneous substrate, which may afford more refuges for certain species. These results suggested that environmental conditions in this area, although they showed certain differences, are favorable for the establishment and development of a diverse brachyuran guild.

Neustonic distribution of decapod planktonic stages and competence of brachyuran megalopae in coastal waters

Settlement rate may not reflect larval supply to coastal waters in different marine invertebrates and demersal fishes. The importance of near-shore oceanography and behaviour of late larval stages may be underestimated. The present study conducted neustonic sampling over station grids and along full-length transects at two embayments in south-eastern Brazil to (1) compare diurnal and nocturnal occurrence of most frequent decapod stages to assess their vertical movements, (2) describe the formation of larval patches and (3) measure competence of crab megalopae according to their distance to recruitment grounds. Several shrimp species apparently undergo a diel vertical migration, swimming crab megalopae showed no vertical movements and megalopae of the intertidal crab Pachygrapsus transversus revealed a reversed vertical migration. During the day, crab megalopae aggregated in convergence zones just below surface slicks. These larvae consisted of advanced, pre-moult stages, at both mid-bay and near-shore patches. Competence, measured as the time to metamorphosis in captivity, was similar between larval patches within each taxon. Yet, subtidal portunids moulted faster to juveniles than intertidal grapsids, possibly because they were closer to settlement grounds. Megalopae of Pachygrapsus from benthic collectors moulted faster than those from bay areas. These results suggest that alternative vertical migration patterns of late megalopae favour onshore transport, and actual competence takes place very close to suitable substrates, where larvae may remain for days before settlement. Lack of correlation between larval supply and settlement for Pachygrapsus suggests that biological processes, besides onshore transport, may play an important role in determining settlement success of coastal crabs.

Nuclear-follower foraging associations among Characiformes fishes and Potamotrygonidae rays in clean waters environments of Teles Pires and Xingu rivers basins, Midwest Brazil

Por meio de observações sub e supra-aquáticas foram registradas associações alimentares do tipo nuclear-seguidor entre três espécies de peixes characiformes - Chalceus epakros, Hemiodus semitaeniatus e Hemiodus unimaculatus - e uma espécie de raia de água doce - Potamotrygon orbignyi - nas bacias dos rios Teles Pires e Xingu, no Centro-Oeste do Brasil. Os peixes teleósteos foram observados seguindo as raias quando estas revolviam o substrato à procura de invertebrados, formando discretas nuvens de sedimento. Essas situações atraíram os peixes que se aproximaram das raias para se alimentar de pequenas presas e outros tipos de alimentos expostos desta forma. Esse é um típico exemplo de relação comensal onde um participante é beneficiado enquanto o outro não é prejudicado e representa o segundo registro na literatura de associação alimentar do tipo nuclear-seguidor entre raias potamotrigonídeas e peixes teleósteos, demonstrando o potencial de estudos naturalísticos para a descoberta de novas interações envolvendo espécies de peixes de água doce.

Antimicrobial resistance and species composition of Enterococcus spp. isolated from waters and sands of marine recreational beaches in Southeastern Brazil

Density, species composition and antimicrobial resistance in bacteria of the Enterococcus genus were evaluated in seawater and sands from 2 marine recreational beaches with different levels of pollution. The 2 beaches showed predominance of Enterococcus faecalis and Enterococcus faecium, in the water and the sand. Dry sand presented higher densities of Enterococcus sp. and higher frequency of resistant strains than wet sand and seawater. The beach with a higher degree of pollution presented higher percentages of resistant strains (66.7% and 61.5%, in sand and in water, respectively) and resistance to a larger number of antimicrobials compared with the less polluted beach, Ilha Porchat (35.7% and 31.25% of resistant strains in sand and water, respectively). in water samples, the highest frequencies of resistance were obtained against streptomycin (38.5%) and erythromycin (25%), whilst in sand, the highest frequencies were observed in relation to erythromycin and tetracycline (38.1% and 14.3%, respectively). These results show that water and sands from beaches with high indexes of faecal contamination of human origin may be potential sources of contamination by pathogens and contribute to the dissemination of bacterial resistance. (C) 2007 Elsevier Ltd. All rights reserved.

Faecal bacteria in Perna perna (Linnaeus, 1758) (Mollusca: Bivalvia) for biomonitoring coastal waters and seafood quality

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

African-Derived mitochondria in South American native cattle breeds (Bos taurus): Evidence of a new taurine mitochondrial lineage

This article reports the nucleotide diversity within the control region of 42 mitochondrial chromosomes belonging to five South American native cattle breeds (Bos taurus). Analysis of these data in conjunction with B. taurus and B. indicus sequences from Africa, Europe, the Near East, India, and Japan allowed the recognition of eight new mitochondrial haplotypes and their relative positions in a phylogenetic network. The structure of genetic variation among different hypothetical groupings was tested through the molecular variance decomposition, which was best explained by haplotype group components. Haplotypes surveyed were classified as European-related and African-related. Unexpectedly, two haplotypes within the African cluster were more divergent from the African consensus than the latter from the European consensus. A neighbor-joining tree shows the position of two haplotypes compared to European/African mitochondrial lineage splitting. This different and putatively ancestral mitochondrial lineage (AA) is supported by the calibration of sequence divergence based on the Bos-Bison separation. The European/African mitochondria divergence might be subsequent (67,100 years before present) to that between AA and Africans (84,700 years before present), also preceding domestication times. These genetic data could reflect the haplotype distribution of Iberian cattle five centuries ago.