1,001 research outputs found

    Housing in “intramural favelas”: considerations on new forms of urban expansion in contemporary times

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    This paper develops a deeper look into new residential appropriations of space in marginalized areas of a large Brazilian city, while highlighting the subjective importance of housing and its meaning beyond the idea of shelter. Firstly, it presents a brief history of Rio de Janeiro’s favelas – the local version of slums – and its relationship with vacant land over the past 100 years. Then, it explains the value of self-built housing and its contribution to the consolidation of multiple and hybrid territories, highlighting their subjective character. Lastly, it presents a case study called Portelinha, located in a set of favelas known as the Maré Complex, stressing how this mixed occupation has transformed the local urban fabric, leading to the emergence of what is referred to as an “intramural favela”. This phenomenon consists of the self-construction of a smaller-scale set of houses within the walls of a former factory turned into an industrial void in the 1990s. The analysis shows how this housing appropriation is articulated with other activities, especially cultural ones, leading to a diversity of social actors, alliances and conflicts, turning it into a real disputed territory. Cases like this reflect the challenges with which architects and planners need to deal with when working in the unequal urban contexts that are so common in the Global South

    Characterization of Herbaspirillum seropedicae gen. nov., sp. nov., a root-associated nitrogen-fixing bacterium.

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    During a survey of the occurrence of Azospirillum spp. in cereal roots, we obtained 119 isolates which could not be identified as members of one of the three previously described Azospirillum species. These strains formed a very homogeneous group of N2-fixing, microaerobic, motile, vibrioid, gram-negative rod-shaped organisms which formed a veillike pellicle in semisolid medium similar to that of Azospirillum spp. However, the new isolates differed from Azospirillum spp. by their smaller cell width (0.6 to 0.7 μm), variable flagellation (one to three flagella on one or both poles), moist brownish colonies, and broader pH and oxygen tolerance for nitrogenase activity. Organic acids were the preferred carbon sources, but glucose, galactose, L-arabinose, mannitol, sorbitol, and glycerol were also used. The guanine-plus-cytosine content of the deoxyribonucleic acid was slightly lower than the guanine-plus-cytosine contents of Azospirillum spp. (66 to 67 mol%). Deoxyribonucleic acid hybridization experiments with 17 strains of the group showed 50 to 100% complementarity, while the levels of hybridization with the type strains of Azospirillum brasilense, Azospirillum lipoferum, and Azospirillum amazonense were 23, 15, and 6%, respectively. For these new isolates we propose a new genus, Herbaspirillum (the name refers to the habitat of the organisms, the roots of cereals, which are herbaceous seed-bearing plants). The type species is named Herbaspirillum seropedicae after the place where it was first isolated. The type strain is strain Z67, which has been deposited in the American Type Culture Collection as strain ATCC 3589

    Random amplified polymorphic DNA analysis of effective Rhizobium sp. associated with beans cultivated in Brazilian cerrado soils.

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    Efficient bean nodulating Rhizobium strains, isolated from different Brazilian cerrado soils, were characterized by RAPD. This study showed great genetic heterogeneity among R. tropici and R. leguminosarum bv. phaseoli strains and allowed the constitution of genetic clusters, besides indicating the most suitable primers for this characterization. The groups of genetically distinct strains can be used in competitiveness studies to select appropriate Rhizobium strains for bean inoculation in cerrado soils
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