Potential changes in bacterial metabolism associated with increased water temperature and nutrient inputs in tropical humic lagoons

Temperature and nutrient concentrations regulate aquatic bacterial metabolism. However, few studies have focused on the effect of the interaction between these factors on bacterial processes, and none have been performed in tropical aquatic ecosystems. We analyzed the main and interactive effects of changes in water temperature and N and P concentrations on bacterioplankton production (BP), respiration (BR) and growth efficiency (BGE) in tropical coastal lagoons. We used a factorial design with 3 levels of water temperature (25, 30 and 35 °C) and 4 levels of N and/or P additions (Control, N, P and NP additions) in five tropical humic lagoons. When data for all lagoons were pooled together, a weak interaction was observed between the increase in water temperature and the addition of nutrients. Water temperature alone had the greatest impact on bacterial metabolism by increasing BR, decreasing BP, and decreasing BGE. An increase of 1°C lead to an increase of ~ 4% in BR, a decrease of ~ 0.9% in BP, and a decrease of ~ 4% in BGE. When data were analyzed separately, lagoons responded differently to nutrient additions depending on DOC concentration. Lagoons with lowest DOC concentrations showed the strongest responses to nutrient additions: BP increased in response to N, P and their interaction, BR increased in response to N and the interaction between N and P, and BGE was negatively affected, mainly by the interaction between N and P additions. Lagoons with the highest DOC concentrations showed almost no significant relationship with nutrient additions. Taken together, these results show that different environmental drivers impact bacterial processes at different scales. Changes of bacterial metabolism related to the increase of water temperature are consistent between lagoons, therefore their consequences can be predicted at a regional scale, while the effect of nutrient inputs is specific to different lagoons but seems to be related to the DOC concentration

Morfologia urbana e qualidade do ar: uma proposição metodológica aplicada em caso empíricono Rio de Janeiro

Considerando a importância das cidades como fontes emissoras de poluentes e polos de concentração de população, o trabalho investigapossíveis impactos de aspectos da forma urbana nas concentrações de poluentes. O artigo discute o estado da artesobre as interações entre a qualidade do ar e indicadoresda forma urbana, compara e testa diferentes indicadores da forma urbana, incluindo um indicador de compacidadetridimensional proposto. O artigo sugere uma forma de modelagem e avaliação dessas relações, e apresenta, por fim, um estudo de caso na cidade do Rio de Janeiro, envolvendo métodos estatísticos aplicados a poluentes (SO2, CO e PI), variáveis morfológicas (taxa de ocupação e percentagem de verticalização) e meteorológicas (vento – direção e velocidade -, precipitação pluvial e temperatura do ar). Os resultados apontam para graus de influência das variáveis taxa de ocupação e verticalização na concentração dos poluentes considerados.Considering the importance of cities as pollutants emission sources and population hubs, the work researches possible impacts of the urban form aspects on pollutants concentrations. The paper discussesthe state of art of interactions between air quality and urban form indexes, compares and tests different indicators of urban form, including a proposed tridimensional compacity index. It.s suggested a way of modeling and testing these relations andpresented a case study in Rio de Janeiro city, involving statistical methods applied to pollutants (SO2, CO e PI), morphological variables (ground space index and verticalization) and meteorological (wind . direction and speed - , rainfall and air temperature). Results point to gradesof influenceof the ground space index and verticalizationon concentrations of considered pollutants

Evolution of the circumstellar disc of alpha Eri

The Halpha line emission formation region in the circumstellar disc of alpha Eri is: a) extended with a steep outward matter density decline during low H$\alpha$ emission phases; b) less extended with rather constant density distribution during the strong Halpha emission. The long-term variation of the Halpha emission has a 14-15 year cyclic B-Be phase transition. The disc formation time scales agree with the viscous decretion model. The time required for the disc dissipation is longer than expected from the viscous disc model.Comment: 3 pages ; to appear in the proceedings of the Sapporo meeting on active OB stars ; ASP Conference Series ; eds: S. Stefl, S. Owocki and A. Okazak

Sugarcane Industry Development Analysis from the Perspective of Agro-Industrial System Quantification

Sugarcane sector has a strong impact as a wealth generator for Brazil. Several authors discuss the importance of quantifying an agro-industrial system. This article aims to analyze the development of the Brazilian sugarcane sector over the past five years and to assess whether the method of mapping and quantification of agribusiness systems (GESis) is a useful tool for analyzing the economic development of an agro-industrial system. The application of the method enabled to see the performance of all the links that make up the agro-industrial system. It also proved to be an important tool to analyze the performance of an agro-industrial system, pointing possible areas for improvement and opportunities. The comparison between both studies contributes to both a better visualization of the sugarcane sector evolution and a better understanding of situational reality of the sector