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1.
We estimate a spatial econometric interaction model for bilateral aggregate FDI stock data between 25 European Union member countries in 2010. We find evidence for spatial spillovers of foreign direct investment for three different types of spatial dependence. Our results document FDI spillovers between neighboring countries of FDI origin countries, neighboring countries of FDI destination countries as well as between neighboring countries of both FDI origin and destination countries. Relying on recently developed methods, we provide the first model‐consistent interpretation of marginal effects of market size (measured by GDP) as well as GDP per capita on bilateral FDI activity. Our research highlights the importance of taking into account spatial lags when estimating bilateral FDI gravity models.  相似文献   

2.
Summary A series of international trials with the potato crop was conducted in eight countries representing widely differing environments. The purpose of the experiments was: (1) to develop a method for obtaining environmental indexes which measure productivity of diverse potato-growing areas, and (2) to construct performance models for individual genotypes based on the environmental indexes. Yield data of 32 genotypes obtained from a series of 13 experiments conducted in the eight countries in 1983 and 1984 were used in the study. The response pattern of the genotypes was studied by a multivariate analysis. Five genotypes were chosen as representatives for different response patterns to the environments and their data were used for calculating a series of independent indexes for each of the experimental sites based on principal component analysis. Performance models for each of the genotypes were constructed by stepwise regression analysis of yields of a genotype on the environmental indexes based on 1983 data. Yield data of 1984 experiments were used to verify the models. Satisfactory correspondence between observed and predicted yields was obtained for most of the genotypes.  相似文献   

3.
为建立不同温度条件下沙门氏菌和大肠杆菌在鲜切苹果表面的生长模型,为实际生产提供参考,一级模型Baranyi模型被用于拟合4、10、15和25℃条件下沙门氏菌和大肠杆菌在鲜切苹果表面的生长,二级模型平方根模型被用于拟合温度与最大生长速率之间的关系。结果发现,在4℃条件下,由于沙门氏菌和大肠杆菌生长受到抑制,没有表现出生长,Baranyi模型不能对其生长进行拟合;在10、15和25℃条件下,Baranyi模型的拟合函数的决定系数均大于0.96,均方根误差均小于0.23,同时拟合模型具有统计学意义(P<0.01);平方根模型的拟合函数的决定系数均大于0.99,均方根误差均小于0.0023,同时拟合模型具有统计学意义(P<0.05)。结果证明所建立的模型能较好地反映沙门氏菌和大肠杆菌在鲜切苹果表面的生长,表明建立的模型能为鲜切苹果的致病菌防治提供实际指导和参考依据。  相似文献   

4.
YI FENG 《Growth and change》1995,26(1):77-104
ABSTRACT This article conducts a time series cross-sectional analysis of Latin American countries over the period of 1982–1988; it examines the relationship between regime type (civilian/military) and polity type (democratic/authoritarian) on one hand, and economic growth on the other, taking advantage of a specially designed econometric method and the availability of large economic and political data sets. The conclusion from this study is that the economy grows faster under a civilian government than under a military government, and both political rights and civil liberties contribute to growth.  相似文献   

5.
In this paper, we study the dynamics of economic growth for 140 countries during the period 1951–2003. The variables representing economic performance are levels and growth rates of per capita gross domestic product. Using the concept of economic regime, we introduce a notion of distance between the dynamical paths of different countries. Then, a minimal spanning tree and a hierarchical tree are constructed from time series to help detect the existence of groups of countries sharing similar economic performance. The two main clusters that are identified over the whole‐time interval can be interpreted as two groups of countries with high and low performance, respectively. The evolution of such clusters shows three main stylised facts: Certain countries move across clusters; the high‐performance cluster tends to span, while the low‐performance one tends to be (more) compact; and the distance between the two groups increases in time.  相似文献   

6.
In the last year, a central issue in regional economic growth debate has been represented by the empirical analysis of Verdoorn's law related to the long‐term dynamic relationship between the rate of growth in output and the productivity growth due to increasing returns. Several papers have tested Verdoorn's law on European countries as well as many other world economies. Recently, attempts have been made to provide foundations for a spatial version of the original law specification. The main contributions were dedicated to the inclusion of spatial dependence in the economic model. Surprisingly, in the literature on Verdoom's law the analysis of the spatial heterogeneity is not often considered. The aim of this paper is the regional analysis of the spatial dependence and heterogeneity in Verdoorn's law, identifying spatial regimes that can be interpreted as clusters of productivity growth in European regions at NUTS 2 level. To pursue this objective, an optimization algorithm for the identification of groups is used. This constitutes a modified version of Simulated Annealing.  相似文献   

7.
Many rural hierarchies are becoming increasingly dominated by a few regional growth centers while the retail sector in adjacent smaller communities either stagnates or declines. This study tests the hypothesis that the rate of adjustment of the retail sector to changing consumer spending patterns is uniform across different ordered communities in a rural hierarchy. Neoclassical investment theory is combined with central place theory to develop a conceptual model of the relationship between the retail sector and investment in a community. A three tiered 49 community hierarchy is constructed using data from the Minnesota Department of Revenue and the Report of Condition and Income of the Board of Governors of the Federal Reserve System. A crosssectional time series ordinary least squares regression model is employed to estimate retail coefficients of adjustment for the hypothesis testing. Regional estimates indicate only partial adjustment in the retail sector across the whole hierarchy to shifts in consumer spending patterns. Community estimates, which decompose the regional estimate, indicate retail businesses in the largest and mid-sized communities adjust totally in one period, but that retail businesses in the smallest communities do not. The faster rates of adjustment by retail businesses in the larger communities to changing consumer spending patterns may augment the development of regional growth centers in rural areas.  相似文献   

8.
陕西省苹果单产非线性预测模型研究   总被引:2,自引:1,他引:1  
为了更好地服务陕西省苹果产业发展,客观定量预测陕西省苹果产量,为政府部门制定苹果产销及产业发展提供科学决策依据,选择影响苹果产量的主要气候资源为预测因子,利用非线性回归分析方法,对陕西省5个苹果主要生产基地县分别建立单产气象因子非线性回归预测模型。模型检验显示,5县各年苹果单产预测的准确率均达73%以上,且该模式能够较准确地反映各县苹果单产情况,预测效果较好。该预测模型是对苹果产量预测技术方法的首次尝试,思路清晰、可操作性强,可为其他省份建立苹果产量预测方法及其他经济林果产量预测方法提供借鉴。  相似文献   

9.
地衣芽孢杆菌产β-甘露聚糖酶分批发酵动力学模型的建立   总被引:2,自引:2,他引:0  
为研究其菌体生长、产物合成以及底物消耗情况,本文以分离自亚麻温水沤麻液的β-甘露聚糖酶高产菌株地衣芽孢杆菌(Bacillus licheniformis)HDYM-04为供试菌株。以初始魔芋粉加入量2 %、接种量6.7 %、初始pH值 8.0、培养温度37 ℃、搅拌速率300 r/min、通气量3 L/min、发酵周期30 h为基础发酵条件进行5L发酵罐发酵。并基于Logistic方程和Luedeking-Piret等方程建立了该菌株的菌体生长、产物生成、底物消耗三个分批发酵动力学模型,其相关系数分别为0.99021、0.98908、0.98812,均达到0.988以上,这些模型能真实描述菌体发酵过程中菌体生长、酶的合成以及底物消耗的情况。该试验为菌株HDYM-04的工业化应用奠定了理论基础并提供了实践指导,为小试数据的放大提供了重要参考。  相似文献   

10.
针对林业生态建设周期长、投入大、碳汇效益产出效率低的现状,笔者从资金、技术、制度、模式等方面探讨了中国温室气体自愿减排交易体系下的林业碳汇项目开发障碍,并结合实际提出拓宽投融资渠道、扩充项目方法学、探索减排量预售制度、提高项目业主抗风险能力等建议,以期为促进林业碳汇项目增长提供参考。  相似文献   

11.
土地违法对经济增长的影响研究分析   总被引:1,自引:1,他引:0  
王伟林 《中国农学通报》2010,26(18):438-442
本文基于土地违法投入对经济增长的作用机理,通过实证研究分析了中国1999-2006年土地违法投入对经济增长的影响及贡献。研究结果:土地违法投入由于其获取方式和途径等不同对社会经济产生不同于合法土地投入的效应,因而产生了不同于合法土地投入对经济增长的贡献。从短期看,违法土地投入对经济增长的产出弹性远远小于合法土地投入,从长期看,违法土地投入不利于土地的合理投入和集约利用,对经济增长并不能产生正的贡献。因此,政府应该从多方面措施入手,最大程度地遏制土地违法现象的发生。  相似文献   

12.
Legumes used as green manure (GMN) may provide on‐farm sources of N for subsequent crops. In warm‐humid climates on sandy soils, however, there is a need to evaluate effects on growth and yield of subsequent crops when GMN substitutes for chemical N fertilizer. We collected time‐series data for 2 years to evaluate growth and ear yield response of sweet corn (Zea mays L. var. Rugosa) in annual rotation with GMN (summer, winter or summer plus winter GMN) and supplemented with 0, 67 or 133 kg chemical N ha−1. Control treatments receiving 0, 67, 133, 200 or 267 kg chemical N ha−1 were used for comparison. Rotation with summer plus winter GMN resulted in more growth and yield benefit for sweet corn than did the other GMN rotations. Compared with control treatments receiving the same chemical N rates, rotation with summer plus winter GMN increased sweet corn ear yield, leaf area index and total plant dry weight and N content by 15–30 %. Despite these benefits, use of high chemical N rate (267 kg chemical N ha−1) resulted in ear yields at least 20 % greater than sweet corn rotated with any GMN and fertilized with reduced N rates. Largest increases in sweet corn dry weight and N content occurred between 4 and 6 weeks after emergence in all treatments. After this period of rapid growth, sweet corn fertilized with 267 kg chemical N ha−1 showed higher N content than all other treatments. Prior to this period of rapid growth, multiple rainfall events in excess of 30 mm may have resulted in leaching of N from GMN residue. Considering the high rainfall levels, low water and N retention capability of sandy soils and rapid N release from GMN during decomposition, future research of GMN in this environment should evaluate options to better match GMN termination with time of greatest potential N uptake from a subsequent crop.  相似文献   

13.
探究定苗时间对峦大杉苗期生长动态与生长节律影响,优化定苗时间,为育苗提供理论与技术支持。以当年生峦大杉幼苗为试验材料,开展不同定苗时间试验,采用定株观测并应用Logistic方程拟合生长动态的方法,分析定苗时间对苗木生长动态和生长节律的影响效应。研究结果表明,定苗时间影响苗高地径生长效应随处理时间推移而显现,是个动态过程。Logistic方程能够很好地拟合峦大杉苗木生长。定苗时间显著影响苗高、地径线性生长速率、最大线性生长速率和线性生长量,但对苗高地径线性生长始期、终期、线性生长持续期无显著性影响;苗高生长初期定苗较其他处理显著提高苗高和地径的线性生长量线性生长速率、最大线性生长速率,建议增加速生期的养分和水分供给以提高苗木质量。峦大杉合理定苗时间是苗高生长初期(6月30日)。  相似文献   

14.
With the implementation of the ‘Go Global’ strategy and the Belt and Road Initiative, Chinese enterprises have gradually grown into the main force of outward foreign direct investment (OFDI) around the world. Overseas and domestic Chinese voluntary associations (CVAs) have actively promoted inward foreign direct investment in China, while their role in helping Chinese enterprises invest abroad has not been fully revealed. To address this lacuna, we explore the role of CVAs in the foreign direct investment of Chinese enterprises in Southeast Asia and the heterogeneity of their roles based on different types of associations. Our main argument is that CVAs play an intermediary role in shaping Chinese OFDI by facilitating bilateral information exchange and resource matching to enable enterprises' global–local interactions. This research contributes to verifying the impact of CVAs on Chinese enterprises' OFDI and providing implications for both host countries to attract investment and multinational enterprises from China and other developing countries to achieve internationalisation.  相似文献   

15.
In the Mekong Region, the Asian Development Bank and partners have promoted economic corridors as a way to achieve regional economic integration and growth. This study evaluates how a transboundary policy narrative of shared prosperity around the East–West Economic Corridor programme emerged, and then how it was elaborated and used, taking a set of border policies of the government of Thailand as cases. For two decades the shared prosperity narrative has been used by a coalition of elite actors to support a programme of investments in road infrastructure, as well as to push for agreements on trade, border logistics, investment and tourism. The shared prosperity narrative has helped maintain support for the programme despite its failures to meet projections and expectations. Although criticised by civil society and experts from time to time, no coherent shared counter‐narrative emerged. Policy elites in Thailand have used the transboundary narrative to justify investments in special economic zones, and transport infrastructure near the border and inside neighbouring countries. Thailand has also reproduced the narrative in support of efforts to bolster tourism cooperation, and negotiate cross‐border trade and logistics agreements. Roads and bridges have been built, underlining how discursive practices have material consequences and reinforce the narrative.  相似文献   

16.
为了准确了解油用型花生籽仁油分积累特性, 筛选适合描述花生籽仁油分累积特性的生长模型, 以6个高油花生品种(系)为材料, 用Richards、Logistic和Gompertz方程拟合了花生籽仁油分累积特征曲线。研究结果表明, Richards方程能够较好地拟合不同花生品种(系)的油分累积特性, 其拟合度优于Logistic和Gompertz方程。不同花生品种(系)间油分累积特性的比较研究结果表明, 籽仁脂肪含量的变化过程基本可以划分为初始积累、快速积累和稳定积累3个阶段, 油分积累主要集中在前2个阶段。提高含油量有提高油分积累速率和延长油分积累持续时间2策略。提高籽仁油分最大积累速率、初始积累阶段油分积累量和快速积累阶段油分积累量是增加籽仁含油量的关键。  相似文献   

17.
Various indices are commonly used to measure growth or decline in communities and regions, but this article suggests another measure which is fairly easy to obtain--the change over time in real assessed market values. Computer storage and analysis of real estate assessment and sales data make it possible to determine accurate true assessment ratios which can be used to calculate reasonable estimates of market values. This article shows the relationship between population growth from 1970 to 1980 and the changes in real assessed market values of various property classes for over 400 Pennsylvania townships. This can provide insight into the kind and nature of community change. The most noteworthy aspect of these data, not apparent in conventional growth measures, is the magnitude of increases of residential property values in all growth categories, but particularly in the high growth townships. This kind of data could be calculated by countries or by regions; this might be more informative and useful to planners and researchers in such form. Comparing local data to regional, community, or state landmark data can help identify strengths and weaknesses or the particular nature of a community's growth.  相似文献   

18.
The study of quantitative trait’s expression over time helps to understand developmental processes which occur in the course of the growing season. Temperature and other environmental factors play an important role. The dynamics of haulm senescence was observed in a diploid potato mapping population in two consecutive years (2004 and 2005) under field conditions in Finland. The available time series data were used in a smoothed generalized linear model to characterize curves describing the senescence development in terms of its onset, mean and maximum progression rate and inflection point. These characteristics together with the individual time points were used in a Quantitative trait loci (QTL) analysis. Although QTLs occurring early in the senescence process coincided with QTLs for onset of senescence, the analysis of the time points made it difficult to study senescence as a continuous trait. Characteristics estimated from the senescence curve allowed us to study it as a developmental process and provide a meaningful biological interpretation to the results. Stable QTLs in the two experimental years were identified for progression rate and year-specific QTLs were detected for onset of senescence and inflection point. Specific interactions between loci controlling senescence development were also found. Epistatic interaction between QTLs on chromosomes 4, 5 and 7 were detected in 2004 and pleiotopic effects of QTLs on chromosomes 3 and 4 were observed in 2005.  相似文献   

19.
茶树树冠结构的多元差分方程组模型   总被引:1,自引:1,他引:0  
茶树的生长、产量和品质受树冠结构的影响,因此利用数学模型来模拟茶树树冠指标的变化可以指导茶树的栽培和管理。考虑到茶树树冠各指标不但相互影响,而且与前几年生长数据相关,针对茶树树冠15个生长指标的18年数据,建立了多元差分方程组模型,并提出了一种结合利用聚类分析和神经网络进行模型参数估计的方法。计算表明,笔者研究中模型的平均相对误差绝对值(MAPE)为0.045828,低于一元差分方程模型的MAPE的平均值0.0618和一元回归方程模型的MAPE的平均值0.0842,精度有明显提高。该方法可以用于其他多维时间序列的差分方程组建模。  相似文献   

20.
Extensive literatures exist on both regional development and the optimum use of nonrenewable resources over time, but the two have not been melded to consider the effect of combining the optimization of resource exploitation with optimization of population growth and infrastructure investment. A model incorporating these dimensions of regional growth is analyzed using control theory to characterize the optimal time paths of the source-related investment, resource use, and infrastructure investment. An example of nonrenewable groundwater use in the Colorado High Plains region is analyzed to show the shortcomings of existing regulatory schemes.  相似文献   

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