Using exploration expenditures to assess the climate for mineral investment

Countries that rely on private investors to find and exploit their mineral resources need reliable indicators of their investment attractiveness. This study explores the use of exploration expenditures for this purpose, focusing primarily on Chile.     

微生物膜下Q235钢腐蚀行为的表面分析

应用现代表面分析技术研究了Q235钢在硫酸盐还原菌(SRB)环境中的腐蚀行为.包括应用原子力显微镜(AFM)和扫描电子显微镜(SEM)观察Q235钢表面的微生物膜形貌和腐蚀形貌,应用X射线衍射仪(XRD)和X光电子扫描仪(XPS)对Q235钢表面进行成分分析.结果表明微生物膜和硫化物膜在金属表面分布不均匀,进而形成浓差电池引起腐蚀,Q235钢的微生物腐蚀主要以点蚀形式发生.     

Phaeocystis globosa核糖体大亚基(28SrDNA)的序列分析与分类学意义

对一株Phaeocystisglobosa的28SrDNA基因序列测定,共得到碱基大小为1795bp的两个序列片段,其中序列一的长度为970bp,序列二的长度为825bp。将Ph.globosa与Ph.antarctica和Prymnesiumpatelliferum同源序列进行对比,发现Ph.globosa与Ph.antarctica仅在序列二中有一个碱基插入/缺失,同源性为99.99%,而与Pr.patelliferum相比,有7处插入/缺失,碱基总变异率为6.13%;研究发现序列一中有一个比较明显的高度保守区和两个高变区;序列二中有两个比较明显的高变区、一个保守区和一个高度保守区。对28SrDNA基因RNA二级结构分析发现,DNA序列保守区在RNA二级结构上也非常保守,与DNA序列分析结果一致,都证明28SrDNA基因只适用于种以上水平的分类研究,不宜用于种间和种下水平的研究。     

4-甲基喹啉的微生物降解研究

从处理油制气废水的活性污泥中分离得到一株可降解喹啉的菌Q10，经鉴定为睾丸酮丛毛单胞菌(Comamonas testosteroni)。该菌还可以降解4——甲基喹啉，本文着重研究了该菌在好氧条件下对4——甲基喹啉降解特性。实验结果表明，该菌在碱性条件下比在酸性条件下更有利于4——甲基喹啉的降解；温度为30℃时降解较快；振荡速度对降解没有明显影响；在适当的细菌浓度和底物浓度水平上，4——甲基喹啉具有较高的降解效率。实验也表明，菌Q10是一株喹啉衍生物广谱降解菌，具有重要的实用价值。     

BDE-28对斑马鱼核受体介导的内分泌干扰效应研究

2,4,4’-三溴联苯醚(BDE-28)在环境中普遍存在,且在长江流域多种水生生物中检出。目前,国内外对高溴代PBDEs(如BDE-47、BDE-99等)的水生脊椎动物内分泌干扰效应报道较多,而BDE-28的有关研究则相对较少。将斑马鱼胚胎暴露于2、20和200μg·L~(-1)的BDE-28后,借助q-RT-PCR方法对幼鱼8个重要受体包括雄激素受体(AR)、甲状腺激素受体(TR)、芳香烃受体(AhR)、雌激素受体(ER)、糖皮质激素受体(GR)、孕烷X受体(PXR)、盐皮质激素受体(MR)和过氧化物酶体增殖物激活受体(PPAR)相关基因的转录水平进行了研究。结果表明,BDE-28暴露可导致AR、TR和Ah R的基因下调,其中核心受体AR和TR在低中高3种浓度下的下调倍数分别为3.03、2.64、10.10和2.21、2.18、2.31,芳香烃受体基因2(ahr2)在暴露于2和20μg·L~(-1)的BDE-28后,下调倍数分别为12.65和9.23,而雌激素受体(er1)基因在低中高浓度显著上调,上调倍数分别为12.29、12.67和15.87,雌激素受体(er2a)基因在2和20μg·L~(-1)BDE-28下的上调倍数分别为10.83和17.19。进一步采用分子对接和分子动力学模拟的方法研究BDE-28与AR、TR、Ah R和ER之间的相互作用。结果显示,BDE-28与这些受体通过疏水和氢键等相互作用稳定结合,动力学模拟后骨架原子的均方根偏差(RMSD)在5 ns后较稳定。由此可知,BDE-28通过AR、TR、Ah R和ER受体介导产生内分泌干扰效应。     

The Kyoto protocol: Empirical evidence of a hidden success

How effective was the Kyoto protocol? International Environmental Agreements (IEA) have been on the rise over the past four decades; however, thus far their effectiveness is controversial. In view of the conflicting results found in the related literature, this paper addresses its effectiveness by utilizing for the first time the generalized synthetic control method (GSCM) to compare the emissions of the industrialized countries with a “No- Kyoto” counterfactual scenario that represents the expected emissions in the absence of the protocol. This method facilitates a robust comparison between treated and control countries as done by Almer and Winkler (2017) and account for the multiple treated units as done by Grunewald and Martinez-Zarzoso (2016), so as to capture the collective nature of the protocol. Results show that the protocol was successful in reducing the emissions of the ratifying countries approximately by 7% below the emissions expected under a “No-Kyoto” scenario, confirming the importance of accounting for the collective nature of the agreement.     

Shared ways of thinking in Brazil about the science–practice interface in ecology and conservation

The debate in the literature on the science–practice interface suggests a diversity of opinions on how to link science and practice to improve conservation. Understanding this diversity is key to addressing unequal power relations, avoiding the consideration of only dominant views, and identifying strategies to link science and practice. In turn, linking science and practice should promote conservation decisions that are socially robust and scientifically informed. To identify and describe the viewpoints of scientists and decision makers on how the science–practice interface should work in order to improve conservation decisions, we interviewed Brazilian scientists (ecologists and conservation scientists, n = 11) and decision makers (n = 11). We used Q methodology and asked participants to rank their agreement with 48 statements on how the science–practice interface should work in order to improve conservation decisions. We used principal component analysis to identify shared viewpoints. The predominant viewpoint, shared by scientists and decision makers, was characterized by valuing the integration of scientific and strategic knowledge to address environmental problems. The second viewpoint, held mostly by decision makers, was distinguished by assigning great importance to science in the decision-making process and calling for problem-relevant research. The third viewpoint, shared only by scientists, was characterized by an unwillingness to collaborate and a perception of scientists as producers of knowledge that may help decision makers. Most participants agreed organizations should promote collaboration and that actors and knowledge from both science and practice are relevant. Disagreements concerned specific roles assigned to actors, willingness to collaborate, and organizational and institutional arrangements considered effective to link science and practice. Our results suggest there is ample room for collaborations and that impediments lie mainly in existing organizations and formal institutional arrangements rather than in negative attitudes between scientists and decision makers.     

Decentralized mechanisms for river sharing

We study decentralized implementation of efficient outcomes through multilateral bargaining in the river sharing problem. We introduce a class of mechanisms in the form of two-stage games in which agents first announce consumption levels and then bargain over monetary compensations. The defining characteristic of a mechanism is the way it assigns bargaining power to agents as a consequence of their locations, inflows, and consumption decisions. We first determine which mechanisms give incentives to always allocate the water efficiently, in the sense that, regardless of the agents' benefit functions, equilibrium play always yields an efficient outcome. Among these, we take an axiomatic approach to single out three mechanisms that guarantee a fair division of the welfare gain obtained through cooperation along the river.     

Estimating the direct and indirect impact of typhoons on plant performance: Evidence from Chinese manufacturers

We quantify the impact of typhoons on manufacturing plants in China. To this end we construct a panel data set of precisely geo-located plants and a plant-level measure of typhoon damage derived from storm track data and a wind field model. Our econometric results reveal that the impact on plant sales can be considerable, although the effects are relatively short-lived. Annual total costs to Chinese plants from typhoons are estimated to be in the range of US$ 3.2 billion (2017 prices), or about 1 per cent of average turnover. When we examine the channels by which plants react to a storm event we find that there is some buffering through an increase in debt and a reduction in liquidity. In terms of propagating the shock through foreign or domestic channels, our estimates suggest that plants prefer to reduce sales to domestic buyers more than foreign buyers and purchases from foreign rather than domestic suppliers. We also find some evidence of a negative indirect effect on turnover through spillovers from customers and a positive effect through damage to very nearby competitors.     

Negotiating housing deal on a polluted day: Consequences and possible explanations

The topic of air pollution has drawn considerable attention globally. In this paper, we examine the immediate effect of air pollution on a substantial decision, that is, a housing purchase. By linking housing purchasing behavior with the air quality in Beijing, we document market participants' behaviors unexplained by rational economic theories. Our main result suggests that the transaction prices on a severely polluted day are 0.65% higher than those of the days without pollution, other things being equal. This translates into approximately 3.51 million yuan daily increase based on the average transaction volume and price on a typical day in Beijing. The heterogeneity analysis further suggests that this effect is mostly driven by non-local and low income buyers. After ruling out rational explanations, we demonstrate that our empirical results are consistent with salience theory under weak assumptions.