关键驱动力作用下的新疆生态系统服务时空格局分析

[目的]恶劣的生态环境和有限的资源驱动着新疆特殊生态系统服务的形成,人类又通过对生态系统服务的消费来满足和提高自身福祉,需要研究其时空变化并辨识主要驱动因素,支持区域可持续发展。[方法]文章构建了融合不同土地利用类型生态系统服务的价值量排序及服务功能强度矩阵的生态系统服务评估体系,并耦合3种关键驱动因子以评估各个因子的驱动强度,实现对生态系统服务热点与冷点变化的驱动及迁移分析。[结果]2000—2010年全疆生态系统服务总体增加,这一时期生态系统服务的热点区大部分转变为2010—2015年的冷点区,且15年来生态系统服务总体呈现小幅下降趋势。3个时期北疆和南疆人为干扰强度均呈增加趋势,由其驱动的生态系统服务则相应减小;南疆地区植被覆盖范围极其有限,故对生态系统服务驱动强度低;降水在北疆和南疆都能够产生高生态系统服务,但降水量的不稳定性能够使生态系统服务产生较大波动。相比于南疆地区,北疆生态系统在外界干扰下能够体现出更强的抗性和整体性,从而实现相对高效的生态系统服务输出。[结论]对关键驱动因子作用下的生态系统服务进行时空变化分析,有助于理解当地生态系统产生变化的原因,从而为当地生态环境保护提供参考。     

Cox Point Processes: Why One Realisation Is Not Enough

We review a rich class of point process models, Cox point processes, and illustrate the necessity of more than one observation (point patterns) in performing parameter estimation. Furthermore, we introduce a new Cox point process model by treating the intensity function of the underlying Poisson point process as a random mixture of normal components. The behaviour and performance of the new model are compared with those of popular Cox point process models. The new model is exemplified with an application that involves a single point pattern corresponding to earthquake events in California, USA.     

Beyond symbolic and substantive: Strategic disclosure of corporate environmental information in China

Under increasing regulatory pressure to disclose environmental impacts, corporate environmental information disclosure (EID) is becoming more prevalent. However, the motives for EID and disclosure approaches (i.e., symbolic or substantive) remain controversial. Using a sample of data for 742 listed manufacturing firms in China across 3 years, we provide evidence to show that the level of EID is significantly positively associated with a firm's advertising intensity and that firms in moderately competitive industries have a higher propensity for adopting an EID‐based differentiated strategy than firms in stronger or weaker competitive industries. We also find that firms that are more sensitive to environmental issues strategically understate their environmental impact when directly facing consumers. Our results suggest that the implementation of corporate EID is strategic and that firms have strong market motives, even under regulatory pressure to demonstrate legitimacy. We discuss this study's contributions to research on EID theory and implications for strategic EID management.     

Size and value effects in high-tech industries: The role of R&D investment

We use monthly US stock data over 55 years from 1962 to 2017 to show that the R&D intensity at firms adds another important dimension to the size and value effects in describing stock returns, especially for small high-tech firms. A trading strategy that double sorts on R&D intensity and size or book-to-market ratio outperforms a simple small-minus-big (SMB) or high-minus-low (HML) strategy in producing higher and more significant portfolio returns. The most profitable schemes involve triple sorts by size, BM, and R&D intensity: the payoffs of buying high-BM/R&D-Active portfolio and selling low-BM/R&D-Inactive portfolio in the small-size/high-tech group and that of buying high-tech/high-BM and selling low-tech/low-BM in the small-size/R&D-active group generate a return of more than 2% on a monthly basis. Our results are robust to alternative classification method of assigning stocks in portfolios.     

基于神经网络的建筑业碳排放强度预测——以京津冀为例

通过统计分析得出影响建筑业碳排放强度的13个影响因素,基于收集的京津冀相关数据,运用逐步回归分析找出其中6个关键因素.借鉴五折交叉验证解决数据稀缺问题,采用神经网络对京津冀建筑业碳排放强度进行预测.利用敏感性分析简化模型,筛选出4个核心因素.结果表明,此模型预测精度高达99％,同时根据挖掘出的核心因素和关键因素,提出建筑业节能减排的建议.     

乌鲁木齐土地利用碳排放强度时空演变研究

[目的]土地利用二氧化碳排放强度是土地低碳利用的重要指标,对其时空调控是协同促进城市二氧化碳排放总量达峰的重要路径。[方法]文章研究基于乌鲁木齐市2005年和2012年1km高空间分辨率排放网格数据(CHRED)和土地利用矢量数据,采用GIS空间分析法,探讨乌鲁木齐市7个城区土地利用二氧化碳排放强度的时空演变特征。[结果](1)从时间上看,乌鲁木齐市7个城区的土地利用变化整体表现为"5增2减"的现象;二氧化碳排放总量从3 431.49万t上升到5 147.96万t,其中以城镇村及工矿用地二氧化碳排放增长最大,由2005年的2 885.15万t增加到2012年的4 139.15万t。(2)从空间上来看,城市向北部和东南部扩展明显,未利用地和耕地迅速减少,城市扩展区的二氧化碳排放量有明显增加;中心城区和城市扩展区二氧化碳排放强度上升最快。(3)从土地利用转移上看,土地利用结构的变化明显,整体呈现草地、耕地和未利用地向城镇村及工矿用地、交通用地、园林地和水域等类型转移。草地、耕地和未利用地向城镇村及工矿用地转移导致的碳排放强度增长最显著,均超过700万t/万hm~2。[结论]绿洲城市不同的土地利用类型二氧化碳排放强度时空差异较为显著,其中城镇村及工矿用地扩张是导致二氧化碳排放增长的主要原因之一。因此,合理控制绿洲城市扩张规模,优化城市用地布局,建立土地利用二氧化碳排放强度核算体系与综合调控政策,将是促进低碳城市建设的重要路径。     

How Collective Engagement Creates Competitive Advantage for Organizations: A Business-Level Model of Shared Vision,Competitive Intensity,and Service Performance

We argue that collective engagement can serve as a unique value-creation capacity at the business level by linking shared vision and service performance. We also propose that competitive intensity will be a market indicator by which management can enhance the effect of shared vision on collective engagement, and indirectly strengthen service performance (through collective engagement). Furthermore, we argue that this distinctive value-creation capability, embedded in collective engagement, generates competitive advantage; specifically, one that competing organizations will struggle to replicate. We examine our moderated-mediation model by using a three-time-point method derived from five different sources in 198 retail-service branches. Our findings indicate that collective engagement, fueled by shared organizational vision, improves service performance. Furthermore, as this conditional indirect effect of shared vision on service quality and customer satisfaction was solely generated through collective engagement rather than other mechanisms (i.e., commitment and involvement), it creates a competitive advantage for engagement-oriented organizations.     

How to reduce energy intensity to achieve sustainable development of China's transport sector? A cross-regional comparison analysis

China's transport sector has been attracting great attention for its excessive energy consumption and ever-increasing pollution emissions. Thus, reducing energy intensity is one of the top priorities of China's ongoing transport upgrade. In this paper, by establishing a panel data regression model derived from the Cobb–Douglas cost function, we focus on investigating the impacts of energy price and transport productivity on transport energy intensity at the national and regional levels. The study uses the provincial panel data for 2005–2016 to perform regression analysis. The results show that: (1) energy price has a significantly negative effect on transport energy intensity in the whole China and the eastern region, whereas it has no significant impacts in the central and western China. (2) Improvements in transport productivity can effectively decrease transport energy intensity in the whole China and the three major regions. (3) Applying an extended data envelopment analysis (DEA) approach, we decompose transport productivity into four components (i.e., technical change, technology gap change, scale efficiency change, and pure efficiency change) and further differentiate their impacts in different regions. The results indicate that these four components have substantially different impacts in each region. These results provide some valuable insights for policymakers and enterprise entities aiming to adopt measures to reduce energy intensity and achieve sustainable development in China's transport sector.     

海南自由贸易港海关通关监管模式研究

习近平总书记在庆祝海南建省办经济特区30周年大会上重要讲话和中央12号文件1精神,对海南建设中国特色自由贸易港作出了重要部署,也为海关支持海南建设中国特色自由贸易港提出了新的任务要求。本文针对这一背景,结合海关贯彻落实党的十九届四中全会精神部署要求,聚焦跨境贸易更加便利、风险防控更加精准、区域经济更加活跃的自贸港建设目标,研究提出"一线放开、二线高效管住"海关通关监管模式,并就如何强化保障、防控风险提出相应建议,积极助推海南建设中国特色自由贸易港。     

The determinants of capital intensity in Japan and the US

We estimate the determinants of capital intensity in Japan and the US, characterized by striking different paths. We augment an otherwise standard Constant Elasticity of Substitution (CES) model with demand-side considerations, which we find especially relevant in the US. In this augmented setting, the elasticity of substitution between capital and labor is placed between 0.74 and 0.90 in Japan, and around 0.30 in the US. We also find evidence of biased technical change, which is capital-saving in Japan but labor-saving in the US. These differences help us explain the diverse experience in the capital deepening process of these economies, and lead us to conclude that demand-side drivers, quite relevant in the US, may also be relevant to account for different growth experiences. A close look at the nature of technological change is also needed before designing one-size-fits-all industrial, economic growth, and/or labor market policies.