Impacts of interruption of the Agulhas leakage on the tropical Atlantic in coupled ocean-atmosphere simulations

In this paper we use a coupled ocean-atmosphere model to investigate the impact of the interruption of Agulhas leakage of Indian ocean water on the tropical Atlantic, a region where strong coupled ocean-atmosphere interactions occur. The effect of a shut down of leakage of Indian ocean water is isolated from the effect of a collapse of the MOC. In our experiments, the ocean model is forced with boundary conditions in the southeastern corner of the domain that correspond to no interocean exchange of Indian ocean water into the Atlantic. The southern boundary condition is taken from the Levitus data and ensures an MOC in the Atlantic. Within this configuration, instead of warm and salty Indian ocean water temperature (cold) and salinity (fresh) anomalies of southern ocean origin propagate into the South Atlantic and eventually reach the equatorial region, mainly in the thermocline. This set up mimics the closure of the ""warm water path"" in favor of the ""cold water path"". As part of the atmospheric response, there is a northward shift of the intertropical convergence zone (ITCZ). The changes in trade winds lead to reduced Ekman pumping in the equatorial region. This leads to a freshening and warming of the surface waters along the equator. Especially in the Cold Tongue region, the cold and fresh subsurface anomalies do not reach the surface due to the reduced upwelling. The anomaly signals are transported by the equatorial undercurrent and spread away from the equator within the thermocline. Part of the anomaly eventually reaches the Tropical North Atlantic, where it affects the Guinea Dome. Surprisingly, the main effect at the surface is small on the equator and relatively large at the Guinea Dome. In the atmosphere, the northward shift of the ITCZ is associated with a band of negative precipitation anomalies and higher salinities over the Tropical South Atlantic. An important implication of these results is that the modified water characteristics due to a shut down of the Agulhas leakage remain largely unaffected when crossing the equatorial Atlantic and therefore can affect the deepwater formation in the North Atlantic. This supports the hypothesis that the Agulhas leakage is an important source region for climate change and decadal variability of the Atlantic.

Litterfall and leaf decomposition in forest fragments under different successional phases on the Atlantic Plateau of the state of Sao Paulo, Brazil

Litterfall and litter decomposition are vital processes in tropical forests because they regulate nutrient cycling. Nutrient cycling can be altered by forest fragmentation. The Atlantic Forest is one of the most threatened biomes in the world due to human occupation over the last 500 years. This scenario has resulted in fragments of different size, age and regeneration phase. To investigate differences in litterfall and leaf decomposition between forest successional phases, we compared six forest fragments at three different successional phases and an area of mature forest on the Atlantic Plateau of Sao Paulo, Brazil. We sampled litter monthly from November 2008 to October 2009. We used litterbags to calculate leaf decomposition rate of an exotic species, Tipuana tipu (Fabaceae), over the same period litter sampling was performed. Litterfall was higher in the earliest successional area. This pattern may be related to the structural properties of the forest fragments, especially the higher abundance of pioneer species, which have higher productivity and are typical of early successional areas. However, we have not found significant differences in the decomposition rates between the studied areas, which may be caused by rapid stabilization of the decomposition environment (combined effect of microclimatic conditions and the decomposers activities). This result indicates that the leaf decomposition process have already been restored to levels observed in mature forests after a few decades of regeneration, although litterfall has not been entirely restored. This study emphasizes the importance of secondary forests for restoration of ecosystem processes on a regional scale.

Response plateau models fitting via isotonic regression

Within the nutritional context, the supplementation of microminerals in bird food is often made in quantities exceeding those required in the attempt to ensure the proper performance of the animals. The experiments of type dosage x response are very common in the determination of levels of nutrients in optimal food balance and include the use of regression models to achieve this objective. Nevertheless, the regression analysis routine, generally, uses a priori information about a possible relationship between the response variable. The isotonic regression is a method of estimation by least squares that generates estimates which preserves data ordering. In the theory of isotonic regression this information is essential and it is expected to increase fitting efficiency. The objective of this work was to use an isotonic regression methodology, as an alternative way of analyzing data of Zn deposition in tibia of male birds of Hubbard lineage. We considered the models of plateau response of polynomial quadratic and linear exponential forms. In addition to these models, we also proposed the fitting of a logarithmic model to the data and the efficiency of the methodology was evaluated by Monte Carlo simulations, considering different scenarios for the parametric values. The isotonization of the data yielded an improvement in all the fitting quality parameters evaluated. Among the models used, the logarithmic presented estimates of the parameters more consistent with the values reported in literature.

Prática da utilização de lancetas ou agulhas na automonitorização da glicemia capilar no domicílio

Estudo descritivo transversal que teve como objetivo conhecer o comportamento de pessoas com diabetes mellitus em relação à prática de utilização das lancetas e/ou agulhas na automonitorização da glicemia capilar no domicílio. O estudo foi realizado em uma Unidade Básica de Saúde no município de Ribeirão Preto-SP, de agosto de 2008 até julho de 2009. Os dados foram obtidos através de entrevista dirigida, com 57 sujeitos. Os resultados mostraram que 41 (71,9%) pessoas reutilizavam as lancetas e/ou agulhas, na frequência de 1 a 5 vezes (52,6%). Todos os sujeitos referiram que não compartilham a mesma lanceta e/ou agulha com outras pessoas. Torna-se necessário incrementar estudos futuros para investigar os riscos e benefícios dessa prática, como também cursos de capacitação em educação em diabetes para os profissionais de saúde, visando atender à complexidade do cuidado dos usuários.

Aplicabilidade da auriculoterapia com agulhas ou sementes para diminuição de estresse em profissionais de enfermagem

Este estudo clínico randomizado objetivou avaliar os níveis de estresse na equipe de Enfermagem de um hospital e analisar a efetividade da auriculoterapia com agulhas e sementes. 75 pessoas com escores médio (44/58,7%) e alto (31/41,3%) de acordo com a Lista de Sintomas de Estresse foram divididas em grupos (controle, agulhas e sementes), que receberam oito sessões nos pontos Shenmen, Rim e Tronco Cerebral e foram avaliados no início, com quatro, oito sessões e follow-up (15 dias). Na análise de variância (ANOVA), constataram-se diferenças entre os grupos, na 3ª avaliação (F=3,963/P=0,023) e follow-up (F=6,136/P=0,003). Tais diferenças foram entre o grupo controle e agulha. Os grupos de intervenção mostraram diferenças (P<0,05) a partir da segunda avaliação, quando comparados dentro do mesmo grupo. Concluiu-se que a auriculoterapia reduziu o estresse em profissionais de enfermagem, com melhores resultados para agulhas do que sementes, em escores altos, com manutenção de efeitos por 15 dias.