近百年广西汛期降水的诊断及预测研究

本文利用奇异谱分析及最大熵谱方法对广西近百年前、后汛期降水进行诊断分析，结果表明：广西前汛期降水主要存在20-30年的长期变化、2～3年左右的准两年振荡及12-16年左右的年代际变化；后汛期降水除存在明显下降趋势外，还存在20-30年的长期变化、2-3年左右的准两年振荡及4年左右振荡周期。且各主要振荡模振幅有明显的低频振荡特征，在不同时段里表现有强有弱。结合白回归方法对重建分最预测的基础上进行降水趋势预测，从1998-2005年预测结果来看，效果较好。     

Successful outcome of pregnancy after treatment of maternal anti-ro (SSA) antibodies with immunosuppressive therapy and plasmapheresis

In this short communication we describe a patient with anti-SSA and anti-SSB antibodies whose first child died of congenital complete heart block (CCHB). During her second pregnancy she was treated with prednisolone, azathioprine, and plasmapheresis, and levels of anti-SSA and anti-SSB antibodies fell significantly. The pregnancy evolved uneventfully and resulted in the birth of an unaffected male infant. This is the fourth reported case of a successful outcome of pregnancy after treatment with immunosuppressive drugs in a woman with a significant risk of recurrence of CCHB.     

基于SSA-XGBoost方法的降水变化趋势预测模型

全球变暖预期下不同区域的未来降水变化,是政府和公众都关心的重要问题,也是全球变化研究的前沿科学问题。预测模型的建立是预测/预估研究的重点和难点,现今不稳定的气候背景对预测模型的精准度提出了更高的要求。为了解决传统方法对长期时间序列预测效果欠佳的问题,本文以泰国南部洞穴石笋δ¹⁸O重建的过去270多年（公元1773—2004年）的降水记录为数据集,提出了SSA-XGBoost预测模型。对原始数据去趋势预处理后,采用奇异谱分析法（SSA）提取前部分数据（1773—1964年）的振荡成分以确定数据的最佳谐波个数,并进行准确的周期信号分量分解;之后用去趋势数据减去周期信号得到随机信号,再利用XGBoost模型对随机项进行预测;最后将预测的序列、趋势曲线和周期信号延拓结果相叠加得到最终的预测数据（1965—2004年）。与其他四种模型（XGBoost、ARIMA、SSA-ARIMA、LightGBM）的预测结果相比,SSA-XGBoost的预测结果与真实值最相近,且MAE和RMSE均最小,R²也更接近1,说明该模型具有更高的精度和稳定性。该研究对于泰国南部等热带地区未来的降水变化趋势预测具有较好的指导意义,也可为其他长时间序列的预估研究提供借鉴。     

Modeling study on seasonal variation in aerosol extinction properties over China

To investigate the seasonal variation of aerosol optical depth(AOD), extinction coefcient(EXT), single scattering albedo(SSA) and the decomposed impacts from sulfate(SO4 2) and black carbon(BC) over China, numerical experiments are conducted from November 2007 to December 2008 by using WRF-Chem. Comparison of model results with measurements shows that model can reproduce the spatial distribution and seasonal variation of AOD and SSA. Over south China, AOD is largest in spring(0.6–1.2) and lowest in summer(0.2–0.6). Over north, northeast and east China, AOD is highest in summer while lowest in winter. The high value of EXT under 850 hPa which is the reflection of low visibility ranges from 0.4–0.8 km 1and the high value area shifts to north during winter, spring and summer, then back to south in autumn. SSA is 0.92–0.94 in winter and 0.94–0.96 for the other three seasons because of highest BC concentration in winter over south China. Over east China, SSA is highest(0.92–0.96) in summer, and 0.88–0.92 during winter, spring and autumn as the concentration of scattering aerosol is highest while BC concentration is lowest in summer over this region. Over north China, SSA is highest(0.9–0.94) in summer and lowest(0.82–0.86) in winter due to the significant variation of aerosol concentration. The SO4 2 induced EXT increases about 5%– 55% and the impacts of BC on EXT is much smaller(2%–10%). The SO4 2-induced increase in SSA is 0.01–0.08 and the BC-induced SSA decreases 0.02–0.18.     

The diversification of the global mining equipment industry – Going new places?

This paper examines the profile of the global mining equipment supply industry, looking at the largest producers and consumers of mining equipment, tracking the changes in global flows of such equipment over the past decade. This paper shows that while the conventional producers of mining equipment (United States, Germany and Japan) have increased exports over the mining boom, the greater gain has been made by countries in the South (particularly China). The destination market for mining equipment has also begun to change, increasingly moving towards new mining sites (in Africa, East Asia and Latin America) and away from the traditional mining countries (Europe and North America). In SSA, China increasingly accounts for a rapidly growing share of mining equipment imports, but this trend is associated with the general increase in imports from China rather than China's resource specific engagement with SSA.     

Dissolution of beryllium in artificial lung alveolar macrophage phagolysosomal fluid

Dissolution of a lung burden of poorly soluble beryllium particles is hypothesized to be necessary for development of chronic beryllium lung disease (CBD) in humans. As such, particle dissolution rate must be sufficient to activate the lung immune response and dissolution lifetime sufficient to maintain chronic inflammation for months to years to support development of disease. The purpose of this research was to investigate the hypothesis that poorly soluble beryllium compounds release ions via dissolution in lung fluid. Dissolution kinetics of 17 poorly soluble particulate beryllium materials that span extraction through ceramics machining (ores, hydroxide, metal, copper-beryllium [CuBe] fume, oxides) and three CuBe alloy reference materials (chips, solid block) were measured over 31 d using artificial lung alveolar macrophage phagolysosomal fluid (pH 4.5). Differences in beryllium-containing particle physicochemical properties translated into differences in dissolution rates and lifetimes in artificial phagolysosomal fluid. Among all materials, dissolution rate constant values ranged from 10⁻⁵ to 10⁻¹⁰ g cm⁻² d⁻¹ and half-times ranged from tens to thousands of days. The presence of magnesium trisilicate in some beryllium oxide materials may have slowed dissolution rates. Materials associated with elevated prevalence of CBD had faster beryllium dissolution rates [10⁻⁷-10⁻⁸ g cm⁻² d⁻¹] than materials not associated with elevated prevalence (p < 0.05).     

Pollution profiles and physicochemical parameters in old uncontrolled landfills

The long-term effectiveness of the geological barrier beneath municipal-waste landfills is a critical issue for soil and groundwater protection. This study examines natural clayey soils directly in contact with the waste deposited in three landfills over 12 years old in Spain. Several physicochemical and geological parameters were measured as a function of depth. Electrical conductivity (EC), water-soluble organic carbon (WSOC), Cl⁻, NH₄⁺, Na⁺ and exchangeable NH₄⁺ and Na⁺ were used as parameters to measure the penetration of landfill leachate pollution. Mineralogy, specific surface area and cationic-exchange capacities were analyzed to characterize the materials under the landfills. A principal component analysis, combined with a Varimax rotation, was applied to the data to determine patterns of association between samples and variables not evident upon initial inspection. The main factors explaining the variation in the data are related to waste composition and local geology. Although leachates have been in contact with clays for long time periods (13-24 years), WSOC and EC fronts are attenuated at depths of 0.2-1.5 m within the clay layer. Taking into account this depth of the clayey materials, these natural substrata (>45% illite-smectite-type sheet silicates) are suitable for confining leachate pollution and for complying with European legislation. This paper outlines the relevant differences in the clayey materials of the three landfills in which a diffusive flux attenuation capacity (A_c) is defined as a function (1) of the rate of decrease of the parameters per meter of material, (2) of the age and area of the landfill and (3) of the quantity and quality of the wastes.