Luminescence characteristics of quartz from Brazilian sediments and constraints for OSL dating

This study analyzes the optically stimulated luminescence (OSL) characteristics of quartz grains from fluvial, eolian and shallow marine sands of northeastern and southeastern Brazil, with especial focus on the applicability of the single-aliquot regenerative dose (SAR) dating protocol. All analyzed Brazilian sediments presented relatively high OSL sensitivity and good behavior regarding their luminescence characteristics relevant for radiation dose estimation. However, some samples from the Lençóis Maranhenses region in northeastern Brazil showed inadequate OSL sensitivity correction, hampering the implementation of the SAR protocol and their ability to behave as a natural dosimeter. While the shallow marine and eolian samples showed a narrow and reliable dose distribution, the fluvial sample had a wide dose distribution, suggesting incomplete bleaching and natural doses estimates dependent on age models

The macroecology of phylogenetically structured hummingbird-plant networks

Aim To investigate the association between species richness, species' phylogenetic signal, insularity and historical and current climate with hummingbird-plant network structure. Location 54 communities along a c. 10,000 kilometer latitudinal gradient across the Americas (39ºN - 32ºS), ranging from sea level to c. 3700 m asl, located on the mainland and on islands, and covering a wide range of climate regimes. Methods We measured null-modeled corrected complementary specialization and bipartite modularity (compartmentalization) in networks of quantitative interactions between hummingbird and plant species. Using an ordinary least squares multi-model approach, we examined the influence of species richness, phylogenetic signal, insularity, and current and historical climate conditions on network structure. Results Phylogenetically-related species, especially plants, showed a tendency to interact with a similar array of partners. The spatial variation in network structure exhibited a constant association with species' phylogeny (R2=0.18-0.19). Species richness and environmental factors showed the strongest associations with network structure (R2=0.20-0.44; R2138 =0.32-0.45, respectively). Specifically, higher levels of complementary specialization and modularity were associated to species-rich communities and communities in which closely-related hummingbirds visited distinct sets of flowering species. On the mainland, warmer temperatures and higher historical temperature stability associated to higher levels of complementary specialization. Main conclusions Previous macroecological studies of interaction networks have highlighted the importance of environment and species richness in determining network structure. Here, for the first time, we report an association between species phylogenetic signal and network structure at macroecological scale. Specifically, null model corrected complementary specialization and modularity exhibited a positive association with species richness and a negative association with hummingbird phylogenetic signal, indicating that both high richness and high inter-specific competition among closely-related 150 hummingbirds exhibit important relationships with specialization in hummingbird-plant networks. Our results document how species richness, phylogenetic signal and climate associate with network structure in complex ways at macroecological scale

ANÁLISE ESPAÇO-TEMPORAL DO CRESCIMENTO IMOBILIÁRIO NOS BAIRROS RENATO PARENTE E NOSSA SENHORA DE FÁTIMA, SOBRAL-CE

Este trabalho tem como objetivo apresentar uma análise da expansão imobiliária em dois bairros localizados na porção noroeste da cidade de Sobral-CE. Esta região da cidade é considerada atualmente como a principal direção de seu crescimento urbano. Para isso foram realizadas interpretações visuais de imagens do aplicativo Google Earth referentes aos anos de 2005 e 2010 visando à delimitação e à caracterização dos padrões espaciais do arruamento, das quadras e das unidades habitacionais identificadas nos loteamentos presentes nestes bairros. As formas dos objetos e feições observadas foram validadas em trabalhos de campo e organizadas em planos de informações por meio do software gvSIG. Os resultados obtidos para o Bairro Renato Parente demonstraram que a construção de moradias tem se desenvolvido mais rapidamente nos setores leste e central da área loteada enquanto que no Bairro Nossa Senhora de Fátima destaca-se uma forte concentração de imóveis no extremo leste e a construção de um condomínio de alto padrão na parte oeste do loteamento. No levantamento de campo ficou evidenciada a ausência de estabelecimentos comerciais e/ou de serviços em ambos os bairros, caracterizando-os como exclusivamente residenciais, excetuando-se apenas a presença de um clube de lazer no Bairro Renato Parente