Efeito de diferentes níveis de Colletotrichum gossypii South var. cephalosporioides Costa, em plantas de algodão no campo e sua incidência nas sementes

A transmissão planta-semente de Colletotrichum gossypii var. cephalosporioides, agente causal da ramulose do algodoeiro, não tem sido correlacionada com a severidade da doença no campo. Entretanto, baixos níveis de incidência têm, muitas vezes, resultado em altos índices de infecção das sementes pelo patógeno. Esse fato induz o cancelamento de campos de produção de sementes em algumas regiões produtoras. Este trabalho teve como objetivo avaliar o efeito de níveis de inóculo inicial, constituído de plantas com sintomas da doença, em relação à incidência da ramulose quando 70% das maçãs estavam formadas, período considerado como de maior suscetibilidade à infecção, bem como a transmissão planta-semente em relação aos níveis de incidência da doença no campo. O experimento foi conduzido durante os anos agrícolas de 2006 e 2007, com níveis de inóculo inicial de 0,0; 0,1; 0,2; 0,4; 0,8 e 1,6% de plantas com sintomas aos 40 dias após a emergência, em blocos casualizados com quatro repetições e parcelas com oito linhas de 15 m. A incidência da ramulose foi avaliada quando 70% das maçãs estavam formadas, em 200 plantas, nas quatro fileiras centrais. Após a colheita, as sementes foram submetidas ao teste de sanidade pelo método do papel de filtro. Observou-se correlação significativa entre os níveis de inóculo inicial e a incidência da doença quando 70% das maçãs estavam formadas, bem como entre os níveis de incidência no campo e a incidência do patógeno nas sementes, sendo esta correlação altamente significativa no ano de 2006. Campos de produção com incidência de ramulose acima de 5% podem induzir níveis elevados de infecção nas sementes.

South american rattlesnake venom: its hemolytic power

The hemolytic power of rattlesnake venom (Crotalus durissus terrificus) was Studied. A high percentage of sample with negative hemolytic power was detected when sheep red blood cells were used. A large number of venoms with hemolytic power, though with a low hemolysis percentage, were detected when liquid, recently extracted venom was used. When crystallized venom was used under the same experimental conditions, a higher percentage ofpositivityfor hemolysis was obtained. When the results obtained on agar plates were compared to those obtained in test tubes, a large number of animals with a higher percentage of hemolysis were detected, though this value was not proportional to the number of animals showing positive plate hemolysis. When the hemolytic power of these venoms was tested on human red blood cells, a large percentage of animals with venoms having a low hemolytic power was also detected. Hemolytic power was much greater when human red blood cells were tested with crystallized venom. The preparation of red blood cells also had an important effect and the use of red blood cells from defibrinated blood is recommended. We conclude that rattlesnake venom has hemolytic power that increases when the venom is crystallized. Red blood cells should be properly preparedfor the lysis reactions. We suggest that the lytic power of the venom is related to venom concentration and to the purity of its fractions.

Temperature, urbanization and body color polymorphism in South Brazilian populations of Drosophila kikkawai (Diptera, Drosophilidae)

Body color polymorphism of urban populations of cosmopolite fly Drosophila kikkawai Burla, 1954 was investigated in relation to its possible association with environmental temperature. Samples of D. kikkawai were collected in spring, summer, autumn and winter between 1987 to 1988, in zones with different levels of urbanization in the southern Brazilian city of Porto Alegre, Rio Grande do Sul. A clear association was observed between darker flies and both seasons with low temperatures and areas of low urbanization (where temperature is generally lower than in urbanized areas). Results of preliminary laboratory experiments involving six generations of flies grown in chambers at temperatures of 17º and 25ºC confirmed this tendency to a relationship between body color and temperature, with allele frequency of the main gene involved in body pigmentation changing over time.

The epidemiology and antigenic characterization of influenza viruses isolated in Curitiba, South Brazil

Several studies conducted all over the world have reported that the influenza virus is associated with great morbidity and mortality rates. In this study, we analyzed the incidence of the influenza virus between 2000 and 2003 in Curitiba. We studied 1621 samples obtained from outpatients and hospitalized patients of both sexes and all ages. The study was conducted at the local primary care health units (outpatients) and at the tertiary care unit (hospitalized) of the General Hospital of the Federal University in the state of Paraná, Brazil. Nasopharyngeal aspirates and, eventually, bronchoalveolar lavage were assayed for the presence of viral antigens, either by indirect immunofluorescence or cell culture. Of the samples studied, 135 (8.3%) were positive for influenza virus, and of those, 103 (76.3%) were positive for type A and 32 (23.7%) for type B. Additionally, positive samples were analyzed by reverse transcription followed by polymerase chain reaction and subtypes H1 and H3 were identified from this group. A high incidence of positive samples was observed mainly in the months with lower temperatures. Furthermore, outpatients showed a higher incidence of influenza viruses than hospitalized patients.

Serologic evidence of the recent circulation of Saint Louis encephalitis virus and high prevalence of equine encephalitis viruses in horses in the Nhecolândia sub-region in South Pantanal, Central-West Brazil

As in humans, sub-clinical infection by arboviruses in domestic animals is common; however, its detection only occurs during epizootics and the silent circulation of some arboviruses may remain undetected. The objective of the present paper was to assess the current circulation of arboviruses in the Nhecolândia sub-region of South Pantanal, Brazil. Sera from a total of 135 horses, of which 75 were immunized with bivalent vaccine composed of inactive Eastern equine encephalitis virus (EEEV) and Western equine encephalitis virus(WEEV) and 60 were unvaccinated, were submitted to thorough viral isolation, reverse transcriptase polymerase chain reaction (RT-PCR) and neutralization tests for Saint Louis encephalitis virus (SLEV), EEEV, WEEV and Mayaro virus (MAYV). No virus was isolated and viral nucleic-acid detection by RT-PCR was also negative. Nevertheless, the prevalence of neutralizing antibodies in horses older than seven months was 43.7% for SLEV in equines regardless of vaccine status, and 36.4% for WEEV and 47.7% for EEEV in unvaccinated horses. There was no evidence of MAYV infections. The serologic evidence of circulation of arboviruses responsible for equine and human encephalitis, without recent official reports of clinical infections in the area, suggests that the Nhecolândia sub-region in South Pantanal is an important area for detection of silent activity of arboviruses in Brazil.

Pseudopsis monica sp. nov. from the western Andes, Peru, with a key to the South American species of Pseudopsis Newman (Coleoptera, Staphylinidae, Pseudopsinae)

Pseudopsis Newman, 1834 is a genus of Pseudopsinae with about 46 species distributed worldwide, five of which have been reported for South America. In this paper P. monica sp. nov. is described and illustrated based on specimens collected in Lima, Peru. A key to South American species of Pseudopsis and a catalog are also provided.

Distribuição de mercúrio total como indicador de poluição urbana e industrial na costa brasileira

The monitoring of the pollution status of the Brazilian coast is hampered by the lack of a consistent environmental indicator. We propose Hg as an environmental proxy to anthropogenic pollution of coastal regions due to its absence in the Brazilian geology, its ubiquity in anthropogenic effluents, and its toxicity. Available data suggest Hg "backgrounds" in coastal sediments of 1-10 ng g-1, in the East and 15-30 ng g-1 in the South. We suggest short sediment cores to establish these values estimating a geo-accumulation index to compare all areas. The distribution of index values showed the majority of southern coast at least moderately contaminated whereas many eastern areas are still pristine.

Labile copper and zinc fractions under different salinity conditions in a shipyard area in the patos lagoon estuary, south of Brazil

Copper and zinc are common elements in paint residues and can be toxic to estuarine organisms. This study aims to determine the labile dissolved and labile particulate fractions (LPFs) of copper and zinc in the estuarine waters of a shipyard in southern Brazil under different salinity levels and in different seasons. The labile dissolved fraction was determined using the diffusive gradient in thin-film (DGT) technique. The variations in DGT-Cu (0.22-1.05 µg L-1), DGT-Zn (0.54-18.39 µg L-1), LPF-Cu (1.22-3.77 µg g-1), and LPF-Zn (4.29-19.12 µg g-1) concentration were related to changes in their physico-chemical parameters and as a result of boat maintenance activities.

The influence of nationalism in Mercosur and in South America: can the regional integration project survive?

The article discusses if nationalism is getting in the way of regional integration through a Brazilian prism due to Brazil’s pivotal role in regional integration in Mercosur and South America.

Brazilian foreign policy towards South America during the Lula administration: caught between South America and Mercosur

The aim of this article is to analyze Brazil's foreign policy towards the South American region during President Lula's administration. As such, the article intends to highlight two specific dimensions: the extent to which foreign policy during this period has differed from previous periods and the relative importance granted by Brazilian diplomacy to recent cooperation and integration efforts, more specifically the Unasur and Mercosur. The article argues that the Lula administration has behaved differently from its predecessors by prioritizing the building up of Brazilian leadership in South America on several different fronts, especially by strengthening multilateral institutions in the region

Brazil and the institutionalization of South America: from hemispheric estrangement to cooperative hegemony

This article argues that Brazil went from a posture of estrangement in relation to the hemispheric project represented by the Free Trade Area of the Americas (FTAA) to a strategy of cooperative hegemony aimed at institutionalizing the South American space and increasing the costs of the FTAA for the United States. Although Brazil was initially isolated, US lack of leadership combined with events at the subregional level ended up turning the tide in the direction of Brazilian interests. These factors help to understand the current institutional configuration of South America.

Trends in South American weapons purchases at the beginning of the new millennium

In recent years, with some frequency it is heard that Latin America, especially South America, is witnessing the rise of an arms race. Frequent reports in the press and strong statements made by politicians in the region have fueled this fear. At the same time, scholars have also reached to this conclusion, as pointed out by Malamud and Garcia: "The famous arms race in Latin America, led by Venezuela, is no longer just talk."

The coexistence of peace and conflict in South America: toward a new conceptualization of types of peace

South America's predominant democratic regimes and its increasing interdependence on regional trade have not precluded the emergence of militarized crises between Colombia and Venezuela or the revival of boundary claims between Chile and Peru. This way, how can we characterize a zone that, in spite of its flourishing democracy and dense economic ties, remain involved in territorial disputes for whose resolution the use of force has not yet been discarded? This article contends that existing classifications of zones of peace are not adequate to explain this unusual coexistence. Thus, its main purpose is to develop a new analytical category of regional peace for assessing this phenomenon: the hybrid peace. It aims to research the evolution of security systems in South America during the previous century and build a new, threefold classification of peace zones: negative peace zones, hybrid peace zones, and positive peace zones.

The international implications of the Chinese model of development in the Global South: Asian Consensus as a network power

This paper analyzes People's Republic of China (PRC) economic and political ascendance in the 21st century focusing on the evolution of the sui generis economic development model and its significances of the evolution of relationship between China and the developing countries in the peripheral "Global South." The objective of this article is to analyze the relationship between China and the Global South (Africa and South America) in the 21st century, characterized as a new Center-periphery global network power based on trade and investment that we call as "Asian Consensus."

South-South relations and the English School of International Relations: Chinese and Brazilian ideas and involvement in Sub-Saharan Africa

The rise of large developing countries has led to considerable discussions of re-balancing global relations and giving greater priority to understanding South-South relations. This paper, in exploring the central ideas of Chinese and Brazilian foreign policy and the behavior of these two rising Southern countries toward Sub-Saharan Africa, argues that the English School of International Relations is well suited to understanding the intentions and actions that characterize South-South relations.