Browsing by Issue Date, starting with "2011-08"
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- Nemo through the looking-glass: a commentary on Desjardins & FernaldPublication . Oliveira, Rui F.; Canario, Adelino V. M.
- Annual characterisation of four Mediterranean coastal lagoons subjected to intense human activityPublication . Cañedo-Argüelles, Miguel; Rieradevall, M.; Farrés-Corell, Roser; Newton, AliceIn the present study the annual variability of the physico-chemical parameters of four coastal lagoons subjected to intense human activity was characterised. The trophic state indices (TSI) of Carlson (1977) and the water quality index TRIX of Vollenweider et al. (1998) were tested and compared with the water quality categories proposed by the European Environmental Agency (2009). All the parameters were sampled monthly from May 2004 to July 2005. There were important differences in the annual variability of the physico-chemical parameters between the lagoons, reflecting the importance of human-induced pressures and the heterogeneity of these environments. The lagoons were in a eutrophic/hypereutrophic state most of the year. Trophic state indices classified the lagoons in a bad or poor trophic state most of the year, and they were not able to discriminate the effect of secondary variables such as freshwater releases, ground waters fluxes or water renewal. Nitrogen was the limiting factor in the lagoon with a higher exchange rate with the sea, while phosphorous was the limiting factor in the other lagoons, due to the high nitrogen external loads and the poor water renewal. The need for developing indices specifically designed for coastal lagoons in order to asses their trophic state is discussed.
- Pollen-based continental climate reconstructions at 6 and 21 ka: a global synthesisPublication . Bartlein, Patrick; Harrison, S. P.; Brewer, S.; Connor, S.; Davis, B. A. S.; Gajewski, K.; Guiot, J.; Harrison-Prentice, T. I.; Henderson, A.; Peyron, O.; Prentice, I. C.; Scholze, M.; Seppa, H.; Shuman, B.; Sugita, S.; Thompson, R. S.; Viau, A. E.; Williams, J.; Wu, H.Subfossil pollen and plant macrofossil data derived from C-14-dated sediment profiles can provide quantitative information on glacial and interglacial climates. The data allow climate variables related to growing-season warmth, winter cold, and plant-available moisture to be reconstructed. Continental-scale reconstructions have been made for the mid-Holocene (MH, around 6 ka) and Last Glacial Maximum (LGM, around 21 ka), allowing comparison with palaeoclimate simulations currently being carried out as part of the fifth Assessment Report (AR5) of the Intergovernmental Panel on Climate Change. The synthesis of the available MH and LGM climate reconstructions and their uncertainties, obtained using modern-analogue, regression and model-inversion techniques, is presented for four temperature variables and two moisture variables. Reconstructions of the same variables based on surface-pollen assemblages are shown to be accurate and unbiased. Reconstructed LGM and MH climate anomaly patterns are coherent, consistent between variables, and robust with respect to the choice of technique. They support a conceptual model of the controls of Late Quaternary climate change whereby the first-order effects of orbital variations and greenhouse forcing on the seasonal cycle of temperature are predictably modified by responses of the atmospheric circulation and surface energy balance.
- Sentinel network for monitoring in vitro susceptibility of Plasmodium falciparum to antimalarial drugs in Colombia: a proof of conceptPublication . Aponte, Samanda L.; Diaz, Gustavo; Pava, Zuleima; Echeverry, Diego F.; Ibarguen, Dario; Rios, Melissa; Murcia, Luz M.; Quelal, Claudia; Murillo, Claribel; Gil, J. P.; Bjorkman, Anders; Osorio, LydaDrug resistance is one of the principal obstacles blocking worldwide malaria control. In Colombia, malaria remains a major public health concern and drug-resistant parasites have been reported. In vitro drug susceptibility assays are a useful tool for monitoring the emergence and spread of drug-resistant Plasmodium falciparum. The present study was conducted as a proof of concept for an antimalarial drug resistance surveillance network based on in vitro susceptibility testing in Colombia. Sentinel laboratories were set up in three malaria endemic areas. The enzyme linked immunosorbent assay-histidine rich protein 2 and schizont maturation methods were used to assess the susceptibility of fresh P. falciparum isolates to six antimalarial drugs. This study demonstrates that an antimalarial drug resistance surveillance network based on in vitro methods is feasible in the field with the participation of a research institute, local health institutions and universities. It could also serve as a model for a regional surveillance network. Preliminary susceptibility results showed widespread chloroquine resistance, which was consistent with previous reports for the Pacific region. However, high susceptibility to dihydroartemisinin and lumefantrine compounds, currently used for treatment in the country, was also reported. The implementation process identified critical points and opportunities for the improvement of network sustainability strategies.