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51.
Gang Liu 《Journal of Chinese Economic and Business Studies》2013,11(3):381-400
In this paper, an economy means a national economy; an economy's relative steady state means an economy's steady state of per-capita output relative to the mean of those of a broad set of economies. This paper provides a method used not only to get the path of an economy's relative steady state, but also to assess whether an economy's relative steady state changed between two given periods and whether an economy's relative steady state in a given period differed from another economy's in the same or a different given period. This paper also shows the paths of relative steady states of six economies (China, India, South Korea, Taiwan, Japan and USA) using the estimates of their relative steady states in four successive periods (1960s, 1970s, 1980s and 1990s). A comparison of the paths gives valuable information. 相似文献
52.
弗里德曼《实证经济学方法论》的发表引发了一场关于经济学方法论的大争论,包括萨缪尔森、西蒙、纳格尔在内的众多知名学者都直接参与了该论战。时至今日,经济学界就经济学的主要目的已达成一致的共识,但是对经济学假设应该具备多大程度上的现实性还存在一定的争议。事实上经济学家经常面临着假设的现实性与易处理性的权衡,经济学理论的创新需要在假设的现实性与易处理性之间找到一个较好的突破点。 相似文献
53.
李卫华 《经济理论与经济管理》2010,(1):45-51
本文针对现代经济学的研究方法及其理论内涵中存在的问题进行研究。通过对现代经济学假设条件及其思维程序的分析,并将科学研究的三种方法与现代经济学的研究方法加以比较,得出的结论是:现代经济学没有事实基础,只是一套凭空杜撰的理论。而数学推理只是用来杜撰理论的工具;经济社会\"客观性\"和经济学\"科学性\"幻觉的驱动以及经济学界生存竞争等使得现代经济学走向远离现实的空想境界;经济学正确的研究方法应该是观察经济社会这个天然实验室中真实的实验结果。 相似文献
54.
三种通过常规气象变量估算实际蒸散量模型的适用性比较 总被引：1，自引：0，他引：1
为了分析比较3种通过常规气象变量估算实际蒸散量模型的适用性,采用无量纲化分析方法将基于互补相关理论的平流-干旱（简称AA模型）模型和Granger模型与Katerji和Perrier提出的通过气象变量确定表面阻力进而直接估算实际蒸散量的PenmanMonteith(PMKaterji)模型转化为类似的可比形式,即将实际蒸散量与Penman潜在蒸散量之比(蒸散比)表示为Penman潜在蒸散量中辐射项所占比例的函数。3种模型分别采用不同的函数形式,通过对函数特性的分析发现, AA模型适用于既不非常干燥和也不非常湿润的环境,计算的实际蒸散量在干燥的环境下偏小,而在湿润的环境下偏大;Granger模型在蒸散比变化范围较大都适用,并且在一般湿润状况下与AA模型近似等价;PMKaterji模型在蒸散比变化范围较大时模拟效果不好。通过干旱(黑河试验沙漠与戈壁站)与湿润(淮河试验安徽寿县站)两种状况下的实测数据的对比分析验证了理论分析的正确性。 相似文献
55.
学报是具有较强正外部性的商品,但政府并没有对这种正外部性给予专项补偿,因此它的运作缺乏激励机制和约束机制。根据经济学中的“理性人”假设,对学报的出资方、编辑、读者、作者的行为进行分析,得出结论:该市场参与者各方从“理性人”角度,为了获取最大利益,进行了最有利于增加自己收益的行为选择。他们的行为选择最终导致学报运营效率低下,资源浪费现象严重,因此,学报运营机制的改变是提高学报社会效益的根本出路。 相似文献
56.
气象数据缺测条件下参照腾发量的计算方法 总被引：55，自引：1，他引：55
利用河北雄县和望都两气象站的数据,对FAO推荐的气象数据缺测时参照腾发量的计算方法进行了检验和评价,分析了参照腾发量对各气象要素的敏感性,提出了在气象数据缺测条件下适应我国北方平原区气候条件的参照腾发量的计算方法。 相似文献
57.
Li Li Pamela L. Sullivan Paolo Benettin Olaf A. Cirpka Kevin Bishop Susan L. Brantley Julia L. A. Knapp Ilja van Meerveld Andrea Rinaldo Jan Seibert Hang Wen James W. Kirchner 《Wiley Interdisciplinary Reviews: Water》2021,8(1)
Headwater catchments are the fundamental units that connect the land to the ocean. Hydrological flow and biogeochemical processes are intricately coupled, yet their respective sciences have progressed without much integration. Reaction kinetic theories that prescribe rate dependence on environmental variables (e.g., temperature and water content) have advanced substantially, mostly in well‐mixed reactors, columns, and warming experiments without considering the characteristics of hydrological flow at the catchment scale. These theories have shown significant divergence from observations in natural systems. On the other hand, hydrological theories, including transit time theory, have progressed substantially yet have not been incorporated into understanding reactions at the catchment scale. Here we advocate for the development of integrated hydro‐biogeochemical theories across gradients of climate, vegetation, and geology conditions. The lack of such theories presents barriers for understanding mechanisms and forecasting the future of the Critical Zone under human‐ and climate‐induced perturbations. Although integration has started and co‐located measurements are well under way, tremendous challenges remain. In particular, even in this era of “big data,” we are still limited by data and will need to (1) intensify measurements beyond river channels and characterize the vertical connectivity and broadly the shallow and deep subsurface; (2) expand to older water dating beyond the time scales reflected in stable water isotopes; (3) combine the use of reactive solutes, nonreactive tracers, and isotopes; and (4) augment measurements in environments that are undergoing rapid changes. To develop integrated theories, it is essential to (1) engage models at all stages to develop model‐informed data collection strategies and to maximize data usage; (2) adopt a “simple but not simplistic,” or fit‐for‐purpose approach to include essential processes in process‐based models; (3) blend the use of process‐based and data‐driven models in the framework of “theory‐guided data science.” Within the framework of hypothesis testing, model‐data fusion can advance integrated theories that mechanistically link catchments' internal structures and external drivers to their functioning. It can not only advance the field of hydro‐biogeochemistry, but also enable hind‐ and fore‐casting and serve the society at large. Broadly, future education will need to cultivate thinkers at the intersections of traditional disciplines with hollistic approaches for understanding interacting processes in complex earth systems. This article is categorized under:
- Engineering Water > Methods
58.
Robert Lensink 《European Journal of Finance》2013,19(2):95-105
Abstract This paper offers the first attempt to test the inverted-U hypothesis for the effect of uncertainty on investment, implied by a number of recent theoretical studies, using a panel of UK firms. It is found that the effect of uncertainty on corporate investment is indeed approximated by an inverted-U shaped relationship: at low levels of uncertainty the effect is positive, but it becomes negative at high levels of uncertainty. This result represents the first empirical verification of the hypothesis with respect to UK firms. 相似文献
59.
Chengze Simon Fan 《Economic Theory》2001,17(2):399-418
Summary. Extending some existing literature, this paper formalizes the idea that intergenerational transfers occur because people care about the “characteristics” (i.e quantity and quality) of their offspring, rather than their children's welfare per se or consumption. The model analyzes this transfer motive in an infinite Markovian game framework, and it proves the existence of a stationary Markov Perfect equilibrium. Further, the analysis shows that under certain conditions, the proposed transfer motive will diminish, as the average income of an economy is sufficiently high. Thus, it suggests that as incomes continue to rise beyond a certain level, the (extended) life-cycle hypothesis will likely be a better and better approximation for explaining most people's saving behavior. This result also provides an explanation for the decline of the saving rates in the U.S. and other developed countries. Received: December 28, 1998; revised version: February 17, 2000 相似文献
60.
This study examines the presence of long-run dependence in a variety of crude and refined energy spot markets during the 1986–2018 period using the time-varying generalised Hurst exponent. Our results indicate that the weak-form efficiency in energy spot markets is clearly time-varying, with USGC(U.S. Gulf Coast Conventional Gasoline) Diesel Fuel the most efficient and Propane the least. An important finding is that after the subprime crisis, the persistence of energy spot market products has increased. Overall, our finding highlights that the time-varying model is preferable to the time-constant one since the former can capture time-varying efficiency, which heavily depends on a country’s predominant economic and political conditions. 相似文献