Natural resource dependence and the accumulation of physical and human capital in Latin America

In a simultaneous model of human and physical capital accumulation for 17 Latin American countries from 1975 to 2004, we show that overall resource dependence has no significant direct effect on physical and human capital. When disaggregating the natural resource variable into sub-categories, we find that petroleum export dependence has a significant positive direct effect on physical capital, but a significant negative direct effect on human capital. Agricultural export dependence shows a significant negative direct effect on physical capital. Petroleum exports have a long run positive effect on physical capital but a negative long run effect on human capital. Agricultural exports have a negative long run effect on physical and human capital.     

Corporate Social Responsibility and development in Africa: Redefining the roles and responsibilities of public and private actors in the mining sector

This paper revisits the role of Corporate Social Responsibility (CSR), suggesting the usefulness of adopting a holistic and historical perspective. It underlines the importance of taking into account the evolving regulatory frameworks within which mining activities take place in order to consider the changing roles played by the various actors involved, whether multilateral, national or local, public or private. In this broad context it then becomes possible to revisit issues of legitimacy, responsibility, and accountability, which CSR strategies aim to address. The article draws attention to the shortcomings of strategies, whether bilateral or multilateral, public or private, which, in an attempt to respond to problems of risk and legitimacy faced by mining companies, have put forward measures in the name of CSR that do not address the origins that give rise to such problems and, in so doing, tend to mask the very nature of the difficulties at hand. The analysis leads to quite different conclusions as compared to those that result from the adoption of a shorter term and investment-led perspective.     

巯基功能化13X分子筛对Pb(Ⅱ)的吸附

用3-巯丙基三甲氧基硅烷（MPTMS）对13X分子筛表面进行修饰,采用XRD和FT—JR测试方法对功能化前后的分子筛结构进行表征,结果表明,功能化后分子筛在保持原有结构同时表面还接枝了对Ph^2＋离子有吸附能力的巯基基团。吸附实验表明,巯基功能化分子筛对水中Ph^2＋离子比原分子筛具有更强的吸附去除效果,饱和吸附容量和去除率提高近一倍。SH-13X对Ph^2＋离子的等温吸附符合Langmuir模型,最大吸附容量为47．01mg／g,吸附强度b为2．26。动力学分析表明SH-13X对Ph^2＋离子的吸附过程更符合准二级动力学模型,而且粒内扩散不是该吸附过程的主要吸附机制。溶液中的Ph“与嫁接在分子筛表面及孔口位置的-SH功能团形成配位络合物而去除。     

南京紫金山马尾松树轮δ13C对气候变化响应敏感性的研究

树木年轮宽度指标在气候重建中发挥了重要的作用,可是在温暖湿润的地区,利用树木年轮宽度重建古气候遇到了困难。因此寻找其他代用指标就成为一项急迫而重要的任务。一些研究发现,树轮稳定碳同位素可以发挥重要的作用。但是,是否所有的树种的树轮碳同位素对气候的响应都同样的敏感,还需要通过大量的研究分析工作来验证。为了了解温暖湿润的亚热带季风区马尾松树轮δ13C对气候响应的敏感性,选取了南京紫金山的两个马尾松树盘,进行了树轮δ13C的分析,建立了1939~2002和1955~2002年两个树轮δ13C变化序列。与降水、温度、相对湿度、光照时数、风速等气候指标进行了相关分析。结果表明：（1）马尾松树轮δ13C对于气候的响应是敏感的,可以作为气候变化的代用指标;（2）坡向对于马尾松树轮δ13C对气候的响应敏感性也有一定的影响,树轮δ13C平均值西南坡比东南坡高,西南坡比东南坡对月平均最低和最高温度的响应更敏感;（3）紫金山马尾松树轮δ13C与该地区生长季（尤其是夏、秋季）的月平均气温、月平均最高气温和日照时数呈正相关,而与月平均最低气温、降水量、空气相对湿度呈负相关     

温州红壤的酸沉降临界负荷研究

本文简要介绍了以碱总量守恒为基础建立的兼能描述钙质与非钙质土壤长期酸化过程的动态模型（ＬＴＳＡＭ）,并利用该模型讨论了温州红壤的酸沉降临界负荷。结果表明,以硫沉降即酸沉降的硫沉降非酸沉降两观点分别来确定红壤的临界负荷,其值依次为３．９１与１．８４ｇ·ｍ＾－２·ａ＾－１,后者仅是前者的４７％,差异显著应加以区别。     

“十三五”环境经济政策建设规划中期评估研究

《"十三五"全国环境保护法规和环境经济政策建设规划》（以下简称《规划》）绘制了"十三五"时期我国环境保护法规和环境经济政策的创新与改革蓝图。"十三五"以来，《规划》实施推动了环境经济政策在生态文明建设生态环境保护工作中的地位快速上升，在筹集环保资金、调控环境行为、激励企业减排等方面发挥了重要作用。为了更好推进环境经济政策改革与创新，本研究采用逻辑框架法对《规划》中期实施进展进行了系统评价，结果表明：在28项《规划》任务中，绿色信贷、环境信息披露制度、环境污染强制责任险等13项任务进展良好，生态环境损害赔偿制度等11项任务进展较好；环境信用建设"入法"等4项规划任务进展较小或者进展一般。研究表明《规划》总体实施顺利，评估工作也为完成2020年《规划》目标提供了重要技术支撑。     

不同施氮量下水稻分蘖期光合碳向土壤碳库的输入及其分配的量化研究：13C连续标记法

应用稳定同位素13C-CO2连续标记技术,通过室内密闭培养试验研究不同施氮处理下(依次为N0,N10,N20,N40,N60)水稻分蘖期光合碳向土壤碳库的输入及其分配特征.结果表明,连续标记培养18 d后,水稻地上部和根系的干物质累积量分别为1.58~4.35 g·plot-1和1.05~2.44 g·plot-1,水稻植株生物量受施氮处理显著影响,且随着施氮量增加而增加,即N60>N40>N20>N10>N0.水稻整个分蘖期内分别有44.0~157.6 g·plot-1和8.3~49.4 g·plot-1的光合碳进入水稻地上部和根系.不同施氮水平下,种植水稻的土壤有机碳(13C-SOC)、可溶性有机碳(13C-DOC)和微生物量碳(13C-MBC)的分配量均显著高于CK处理(不种植水稻且不施N).种植水稻的土壤13C-SOC含量范围为11.1~23.7 g·plot-1,占总净同化量的10.2%~18.1%.对于活性碳库,CK处理的土壤13C-DOC和13C-MBC含量分别为3.50μg·kg-1和88.9μg·kg-1,种植水稻处理的土壤13C-DOC、13C-MBC含量范围为4.82~14.51μg·kg-1、526.1~1 478.8μg·kg-1.土壤13C-SOC、13C-DOC和13C-MBC含量受施氮处理显著影响(P<0.05),且与植物生物量呈显著正相关关系.因此,水稻分蘖期光合碳的地下部输入有利于土壤有机碳的累积,施氮能够促进水稻新鲜根际碳的沉积,且高N水平下根际沉积碳量高于低N和中量N水平.     

施氮和水分管理对光合碳在土壤-水稻系统间分配的量化研究

施肥和水分管理是影响水稻生长的两个关键因素,探讨水肥耦合条件下光合碳在"水稻-土壤"系统输入与分配动态,对深入解析稻田土壤碳循环具有重要意义.本研究通过盆栽试验,选用籼性常规水稻品种(中早39),采用13C-CO_2连续标记技术,量化研究施氮和水分管理对光合碳在"水稻-土壤"系统中分配的影响.结果表明:施氮增加了水稻地上部干物质重和碳、氮含量,却显著降低了水稻根冠比;干湿交替使施氮条件下的水稻地上部全碳、全氮含量较持续淹水处理分别提高了22%和33%,根系中全碳、全氮含量分别提高了36%、44%,这表明施氮有利于水稻地上部生长,而干湿交替显著促进了水稻根系的生长.施氮显著增加水稻地上部13C含量,与不施氮处理相比增加了32%~83%;施氮使光合碳在水稻地上部的回收率增加6%~32%,在根系的回收率减少18%~59%.水分管理对13C分配的影响表现为:连续标记22 d后,在施氮条件下,干湿交替使水稻地上部、根系13C量均有一定量的增加;不施氮条件下,干湿交替与持续淹水处理相比,地上部13C量减少10.3mg·pot-1,回收率降低了11%~12%;根系13C量增加1.9 mg·pot-1,回收率提高了24%~57%.施氮和干湿交替都显著增加了13C在根际土壤中的累积与回收率.因此,施氮增加了光合碳在土壤-水稻系统中的累积,但降低了光合碳在根系中的分配,干湿交替比持续淹水更利于光合碳向土壤中的传输与累积,水肥耦合管理显著调控了光合碳的传输与分配.该研究进一步量化了水肥管理条件下水稻光合碳的分配及其在土壤有机碳库中的传输特征,为稻田水肥管理、水稻土有机质积累持续机制提供了理论依据和数据支撑.     

天津市“十三五”期间PM2.5减排效果评估

为了解“十三五”期间天津市PM_2.5减排效果,基于2015～2020年不同大气污染治理措施的减排量核算结果,利用空气质量模型和高时空分辨率PM_2.5监测数据,对“十三五”期间天津市PM_2.减排效果进行分析.结果表明,2015～2020年,天津市SO₂、 NO_x、 VOCs和PM_2.5的排放量分别减少4.77×10⁴、 6.20×10⁴、 5.37×10⁴和3.53×10⁴t,其中工艺过程、散煤和电力治理对SO₂的减排贡献大,工艺过程、电力和钢铁治理对NO_x的减排贡献大,工艺过程对VOCs的减排贡献最大,工艺过程、散煤和钢铁治理对PM_2.5的减排贡献大.“十三五”期间天津市PM_2.5浓度平均值、污染天数和重污染天数明显下降,分别较2015年下降31.4%、 51.2%和60.0%;与前...     

Efficient purification of Al30 by organic complexation method

A method was developed for preparing high purity Al₃₀O₈(OH)₅₆(H₂O)₂₄^18 + (Al₃₀) through elimination of impurities by complexation. Polyaluminum chloride II (PAC₃₀) with Al_c content of 75% was adopted as the source of Al₃₀. The PAC₃₀ was prepared under conditions of total aluminum concentration 0.1?mol/L and OH^?/Al ratio 2.2 to obtain the highest content of Al₃₀. A precipitation/metathesis method, organic solvent precipitation method and organic complexation method were examined to separate and purify Al₃₀. It was found that only by the organic complexation method could high purity Al₃₀ products be obtained in large yield economically. In the experiments, benzoic acid was used as the coordinating reagent to decompose the main impurity AlO₄Al₁₂(OH)₂₄(H₂O)₁₂^7 + (Al₁₃), and the Al₃₀ product could be obtained by precipitation and metathesis operations. It was noteworthy that the decomposition of impurities by benzoic acid could be completed in 2?hr. The Al₃₀ product was characterized by Ferron assay, ²⁷Al-NMR, SEM, XRD and TGA. The results showed that the purity of the Al₃₀ product could exceed 92%.