Climate change and infectious diseases: Can we meet the needs for better prediction?

The next generation of climate-driven, disease prediction models will most likely require a mechanistically based, dynamical framework that parameterizes key processes at a variety of locations. Over the next two decades, consensus climate predictions make it possible to produce forecasts for a number of important infectious diseases that are largely independent of the uncertainty of longer-term emissions scenarios. In particular, the role of climate in the modulation of seasonal disease transmission needs to be unravelled from the complex dynamics resulting from the interaction of transmission with herd immunity and intervention measures that depend upon previous burdens of infection. Progress is also needed to solve the mismatch between climate projections and disease projections at the scale of public health interventions. In the time horizon of seasons to years, early warning systems should benefit from current developments on multi-model ensemble climate prediction systems, particularly in areas where high skill levels of climate models coincide with regions where large epidemics take place. A better understanding of the role of climate extremes on infectious diseases is urgently needed.     

用于中阿合作的卫星激光测距(SLR)系统的现状和未来

简要介绍了用于中国科学院国家天文台与阿根廷San Juan大学合作观测与研究的一个高精度卫星激光测距(SLR)系统.该望远镜口径为60cm的SLR系统由中国研制,于2005年秋被运往阿根廷,安装在阿根廷国立San Juan大学天文台,San Juan大学建立了观测室.准备了工作条件.该系统于2006年2月底完成调试并开始运行.在过去的两年阃,该系统保持了良好的工作状态,由于San Juan具有良好的天气条件,该系统取得了丰富的高精度观测资料.国际激光测距服务认为该仪器的工作对国际激光测距系统是重要的,希望对其增加白天测距的功能.文章也简单介绍了该SLR站未来升级改造和发展的计划.     

Trees, lateral shrinkage and building damage

This article presents the study conducted and the actions taken to stabilise the foundations of 25 low-rise (two/three-storey) buildings in Alcázar de San Juan (Ciudad Real, central Spain). Owing to the immediate attention required, it was decided that the study would focus on procuring a synthetic model that would be able to provide a satisfactory explanation for the tendency of the movements, overlooking the detailed model of each building. This analysis pointed out that the mobilisation was probably due to both the shrinkage caused by the existing trees during the dry-growing seasons, and to the loss of lateral confinement caused by the excavation of a service trench adjacent to the footings of the buildings. In keeping with this mechanism, stabilization was carried out by transplanting the trees growing near the damaged buildings and installing a line of piles to provide lateral support to the footings. The evolution of the damage was therefore stopped.     

Selenite retention by nanocrystalline magnetite: Role of adsorption, reduction and dissolution/co-precipitation processes

We studied selenite () retention by magnetite () using both surface complexation modeling and X-ray absorption spectroscopy (XAS) to characterize the processes of adsorption, reduction, and dissolution/co-precipitation. The experimental sorption results for magnetite were compared to those of goethite (Fe^IIIOOH) under similar conditions. Selenite sorption was investigated under both oxic and anoxic conditions and as a function of pH, ionic strength, solid-to-liquid ratio and Se concentration. Sorption onto both oxides was independent of ionic strength and decreased as pH increased, as expected for anion sorption; however, the shape of the sorption edges was different. The goethite sorption data could be modeled assuming the formation of an inner-sphere complex with iron oxide surface sites (SOH). In contrast, the magnetite sorption data at low pH could be modeled only when the dissolution of magnetite, the formation of aqueous iron-selenite species, and the subsequent surface complexation of these species were implemented. The precipitation of ferric selenite was the predominant retention process at higher selenite concentrations (>1 × 10⁻⁴ M) and pH < 5, which was in agreement with the XAS results. Sorption behavior onto magnetite was similar under oxic and anoxic conditions. Under anoxic conditions, we did not observe the reduction of selenite. Possible reasons for the absence of reduction are discussed. In conclusion, we show that under acidic reaction conditions, selenite retention by magnetite is largely influenced by dissolution and co-precipitation processes.     

Watershed morphometric analysis of Wadi Baish Dam catchment area using integrated GIS-based approach

The integration of Remote Sensing (RS) and Geographic Information Systems (GIS) constitutes a powerful tool for the evaluation of watershed morphometric parameters. The benefits of this integration include saving time and effort as well as improving the accuracy of the analysis. Moreover, this technique is appropriate for describing the watershed and its streams. In this study, a detailed morphometric analysis of the Wadi Baish catchment area has been performed using the Shuttle Radar Topography Mission (SRTM). The performed morphometric analysis includes linear, areal, and relief aspects. The results of the morphometric analysis reveal that the catchment can be described as of eighth stream order and consists of an area of 4741.07 km². Additionally, the basin is characterized by a relatively high mean value of bifurcation (4.012), indicative of the scarcity of permeable rocks with high slope in the area. This value of bifurcation ratio is consistent with the high drainage density value of 2.064 km/km² and confirms the impermeability of the subsurface material and mountainous relief. The hypsometric integral of the catchment is 47.4%, and the erosion integral of the catchment is 52.6%, both were indications of a mature catchment area.     

Comparing generalized Pareto models fitted to extreme observations: an application to the largest temperatures in Spain

In this paper, a subsampling-based testing procedure for the comparison of the exceedance distributions of stationary time series is introduced. The proposed testing procedure has a number of advantages including the fact that the assumption of stationary can be relaxed for some specific forms of non-stationary and also that the two time series are not required to be independently-generated. For this purpose, a test based on the Kolmogorov–Smirnov and the L ₁-Wasserstein distances between generalized Pareto distributions is introduced and studied in some detail. The performance of the testing procedure is illustrated through a simulation study and with an empirical application to a set of data concerning daily maximum temperature in the 17 autonomous communities of Spain for the period 1990–2004. The autonomous communities were clustered according to the similarities of the fitted generalized Pareto models and then mapped. The cluster analysis reveals a clear distinction between the four northeast communities on the shores of the Bay of Biscay (which are the regions exhibiting milder temperatures) and the remaining regions. A second cluster corresponds to the southern Mediterranean area and the central region which corresponds to the communities with highest temperatures.     

The exotic aquatic mud snail Potamopyrgus antipodarum (Hydrobiidae, Mollusca): state of the art of a worldwide invasion

Biological invasions represent a relevant ecological and economic problem of our globalized world. While a few species have been classified as invasive due to their ecological and economic impacts on the invaded ecosystems (e.g., zebra mussel), others show contrasting invasive potential, depending on the invaded ecosystem and/or the traits of the exotic species. This paper reviews the worldwide distribution, ecological impacts and the reasons that explain the invasive success of the aquatic mud snail Potamopyrgus antipodarum Gray (Hydrobiidae, Mollusca), which is native to New Zealand. This review shows that most studies on P. antipodarum distribution have been conducted in Europe, North America and Australia, and few studies in Asia. The distribution of this snail is still unknown in other parts of the world (e.g., Africa, South and Central America). The range of invaded aquatic ecosystems varies from fresh to salt water and from lentic to lotic ecosystems. The ecological impact of this species is due to the fast population growth rate and to the extremely high densities that it can reach, leading to altered C and N cycles in invaded ecosystems. However, at low densities mud snails have been shown to enhance secondary production. Additionally, P. antipodarum has been found to overcome the negative effects of predators and parasites (e.g., it survives the pass through the digestive tracts of fish). This review contributes to assess the magnitude and ecological risk of P. antipodarum invasion throughout the world.     

Removal of Pyridine from Aqueous Solution by Adsorption on an Activated Carbon Cloth

Pyridine is a very toxic pollutant that has to be removed from wastewater. In this work, adsorption of pyridine on activated carbon cloth (ACC) is studied as a possible alternative for eliminating pyridine from aqueous solution. The ACC was produced from polyacrylonitrile. The adsorption equilibrium data of pyridine on ACC was obtained in a batch adsorber. The experimental data was interpreted with the isotherms of Langmuir, Freundlich, and Prausnitz‐Radke (PR), and the PR isotherm better represented the experimental data. The capacity of ACC for adsorbing pyridine was favored increasing the solution pH from 3 to 6, and this effect was due to the π–π dispersive and electrostatic interactions between the pyridine species in solution and the surface complexes of ACC. The modified Langmuir model fitted reasonably well the influence of pH on the adsorption capacity. In this model was assumed that both neutral pyridine and pyridinium were simultaneously adsorbed on ACC accordingly to the experimental results. The adsorption capacity was almost independent of temperature. The reversibility study revealed that 75% of the pyridine can be desorbed from ACC indicating that part of the pyridine was irreversibly adsorbed, and possibly chemisorbed.     

Flow time estimation with spatially variable hillslope velocity in ungauged basins

The automated spatial estimation of the hillslope runoff dynamics is used as a valuable tool for the estimation of the travel time distribution (flow time), a major factor for the hydrologic prediction in ungauged basins. In fact, while the flow time function is usually obtained by rescaling the flow paths with constant channel and hillslope velocities, in this work a spatially distributed kinematic component, as a function of terrain features and in particular slope and land use, is implemented and its influence on the hydrologic response is tested by means of the Width Function Instantaneous Unit Hydrograph (WFIUH) framework. Hillslope surface flow velocities are evaluated by applying different uniform flow formulas within an automated DEM-based (terrain analysis) algorithm. A comparison test of the performances of the Manning, Darcy, Maidment and Soil Conservation Service uniform flow equations is performed for several case studies in Italy pertaining to different climatic and geomorphic conditions. Results provide new insights for a better understanding of the flow time function also introducing a more parsimonious and physically-based calibration scheme of the WFIUH.