企业异质、地区异质与多要素流动

本文将企业异质、地区异质与多要素流动统一到新经济地理学的分析框架中,发展了企业异质的新经济地理学模型。研究结果表明,当满足产业集聚的强条件时,企业分布异质性的增强强化了产业集聚的“黑洞条件”,反之,则会强化产业的分散力;区域间异质性增大导致区域均衡发展越来越困难。如果区域间的初始禀赋条件相同,则对称结构可能是一种稳定均衡结构,这时对称结构稳定对应的贸易自由度范围最宽。反之,如果区域间的初始禀赋条件不同,这时内部一般非对称结构可能成为一种稳定均衡结构,但这时对应的贸易自由度范围有所变窄;在区域异质性的条件下,内部非对称结构可能是一种稳定均衡结构,当地区同质时,该内部非对称结构就会演变为对称稳定均衡结构,并且,存在多重稳定均衡结构的现象。随着贸易自由度的提高,集聚是可能的,也是渐进的,这一过程会变得可逆。

政策不确定性的宏观经济溢出效应:地区异质与时变特征

文章首先通过反事实模拟检验政策不确定性的宏观经济溢出效应,随后分别运用PVAR模型和TVP-VAR模型探讨该溢出效应的地区异质与时变调整特征。研究发现:如果某段期间不存在政策不确定性,则该段时期经济将呈现更高的产出和通胀以及更低的杠杆率;受经济金融发展和政策制度保障等因素影响,政策不确定性对产出、通胀和杠杆的影响力度由东部至西部地区顺次递增;随着经济政策“逆周期调节”的加强、社会保障逐步健全以及直接融资规模比重不断提高,政策不确定性的宏观经济溢出效应呈现逐渐减弱态势。政策决策部门要保持政策调控的连续性和政策取向稳定性,以减弱政策不确定性对宏观经济的不利冲击。

区块链技术对核心企业运营效率的影响--以区块链技术支持下供应链业务为例

为明确区块链技术对核心企业运营效率的影响,基于2021-2022年我国A股上市公司数据,利用固定效应模型实证分析了区块链技术与区块链技术支持下的供应链金融业务与核心企业运营效率之间的关系,并进一步拓展分析了不同企业规模和地域对核心企业运营效率的差异性影响。结果表明,区块链技术能有效提高核心企业运营效率,在区块链支持下的供应链金融业务中,存货融资模式和预付账款融资模式对核心企业具有显著的支持作用,而应收账款融资模式现阶段支持作用暂不显著,同时,与大型核心企业相比,区块链技术对中小型核心企业支持力度更大;与西部相比,区块链技术对中东部核心企业支持力度更大。结合上述分析,就如何促进区块链技术更好地支持核心企业发展,提高核心企业参与区块链业务积极性,从核心企业自身以及政府和监管部门层面提出相应建议。

Available Contents of Trace Nutrient Element and Factors Affecting Their Availability in Western Jilin

Based on the assay of the total content and available content of the trace nutrient elements and the soil pH and organic matter of the soil samples,the characteristic of the available content of the trace nutrient elements and their affecting factors are studied. The results show that the available B in western Jilin is in a middle level,the content in Nong'an is higher than that in the others; the available Mn is extremely abundant; the available Cu in Nong'an is obviously higher than other areas,and the content in Da'an differs greatly; the available Zn is in a middle level; the severe shortage of available Mo differs between different areas; and the available Fe is extremely abundant. The available Mn,Cu and Fe have significantly positive correlation with their total content; the available B has significantly positive correlation with pH,and Zn has obviously negative correlation with pH; the available Mn and Fe had significantly positive correlation with soil organic matter.

Spatial Heterogeneity of Soil Mineral Oxide Components in Depression Between Karst Hills,Southwest China

In karst regions,the spatial heterogeneity of soil mineral oxides and environmental variables is still not clear.We investigated the spatial heterogeneity of SiO2,Al2O3,Fe2O3,CaO,MgO,P2O5,K2O,and MnO contents in the soils of slope land,plantation forest,secondary forest,and primary forest,as well as their relationships with environmental variables in a karst region of Southwest China.Geostatistics,principal component analysis(PCA),and canonical correlation analysis(CCA)were applied to analyze the field data.The results show that SiO2was the predominant mineral in the soils(45.02%–67.33%),followed by Al2O3and Fe2O3.Most soil mineral oxide components had a strong spatial dependence,except for CaO,MgO,and P2O5in the plantation forest,MgO and P2O5in the secondary forest,and CaO in the slope land.Dimensionality reduction in PCA was not appropriate due to the strong spatial heterogeneity in the ecosystems.Soil mineral oxide components,the main factors in all ecosystems,had greater influences on vegetation than those of conventional soil properties.There were close relationships between soil mineral oxide components and vegetation,topography,and conventional soil properties.Mineral oxide components affected species diversity,organic matter and nitrogen levels.

新时代下税制结构安排与经济高质量发展——来自中国分税制改革后的省际证据考察

有效的税制结构安排是推进新时代下财税体制改革的重要抓手。基于此,本文选择中国省级面板数据和动态效应模型探讨税制结构安排对我国经济高质量发展的影响。研究发现,总体分析上,直接税和间接税都对经济高质量发展产生积极的影响。时序分析上,1995~2003年和2004~2011年两个区间段,间接税对经济高质量发展的作用都超过了直接税;2012~2019年区间段,直接税对经济高质量发展的作用超过间接税。地区异质分析上,东部地区与总体结果基本保持一致;中部地区表现为直接税的正向促进和间接税的反向抑制;而西部地区则恰好与之相反。故此,应进一步增加直接税比重,优化间接税内部税种结构,以发挥税制结构调整对经济高质量发展的促进作用。

Regional differences in crustal structure of the North China Craton from receiver functions

Moho depth and crustal average Poisson＇s ratio for 823 stations are obtained by H-n： stacking of receiver functions. These, to- gether with topography and receiver function amplitude information, were used to study the crustal structure beneath the North China Craton （NCC）. The results suggest that modified and preserved crust coexist beneath the craton with generally Airy-type isostatic equilibrium. The equilibrium is relatively low in the eastern NCC and some local areas in the central and western NCC, which correlates well with regional geology and tectonic features. Major differences in the crust were observed beneath the eastern, central, and western NCC, with average Moho depths of 33, 37, and 42 km and average Poisson＇s ratios of 0.268, 0.267 and 0.264, respectively. Abnormal Moho depths and Poisson＇s ratios are mainly present in the rift zones, the northern and southern edges of the central NCC, and tectonic boundaries. The crust beneath Ordos retains the characteristics of typical craton. Poisson＇s ratio increases roughly linearly as Moho depth decreases in all three parts of the NCC with different slopes. Receiver function amplitudes are relatively large in the northern edge of the eastern and central NCC, and small in and near the rifts. The Yanshan Mountains and southern part of the Shanxi rift show small-scale variations in the receiver-function ampli- tudes. These observations suggest that overall modification and thinning in the crust occurred in the eastern NCC, and local crustal modification occurred in the central and westem NCC. Different crustal structures in the eastern, central, and western NCC suggest different modification processes and mechanisms. The overall destruction of the crustal structure in the eastern NCC is probably due to the westward subduction of the Pacific Plate during the Meso-Cenozoic time; the local modifications of the crust in the central and western NCC may be due to repeated reactivations at zones with a heterogeneous structure by successive thermal-tectonic events during the long-term evolution of the NCC.

Regional Diferences in the Efect of Climate and Soil Texture on Soil Organic Carbon

The agricultural soil carbon pool plays an important role in mitigating greenhouse gas emission ana unaerstanamg the son orgamc carbon-climate-soil texture relationship is of great significance for estimating cropland soil carbon pool responses to climate change. Using data from 900 soil profiles, obtained from the Second National Soil Survey of China, we investigated the soil organic carbon （SOC） depth distribution in relation to climate and soil texture under various climate regimes of the cold northeast region （NER） and the warmer Huang-Huai-Hai region （HHHR） of China. The results demonstrated that the SOC content was higher in NER than in HHHR. For both regions, the SOC content at all soil depths had significant negative relationships with mean annual temperature （MAT）, but was related to mean annual precipitation （MAP） just at the surface 0-20 cm. The climate effect on SOC content was more pronounced in NER than in HHHR. Regional differences in the effect of soil texture on SOC content were not found. However, the dominant texture factors were different. The effect of sand content on SOC was more pronounced than that of clay content in NER. Conversely, the effect of clay on SOC was more pronounced than sand in HHHR. Climate and soil texture jointly explained the greatest SOC variability of 49.0% （0-20 cm） and 33.5% （20-30 cm） in NER and HHHR, respectively. Moreover, regional differences occurred in the importance of climate vs. soil texture in explaining SOC variability. In NER, the SOC content of the shallow layers （0-30 cm） was mainly determined by climate factor, specifically MAT, but the SOC content of the deeper soil layers （30-100 cm） was more affected by texture factor, specifically sand content. In HHHR, all the SOC variability in all soil layers was predominantly best explained by clay content. Therefore, when temperature was colder, the climate effect became stronger and this trend was restricted by soil depth. The regional differences and soil depth influence underscored the importance of explicitly considering them in modeling long-term soil responses to climate change and predicting potential soil carbon sequestration.