自然保护地自然资源资产产权制度现状辨析

“建立以国家公园为主体的自然保护地体系”是党的十九大所提出的国家公园体制建设的新方向。实现自然保护地的有效保护管理是其重要内容，关键在于通过改革形成科学、合理的自然资源资产产权制度，而厘清自然资源资产产权制度的现状则是进行改革的前提。首先，对现行法律进行系统梳理，明确法律所认定的自然保护地中的自然资源类型。其次，从自然资源的产权种类及所有权改变、用益物权流转三方面总结了自然保护地自然资源资产的产权制度现状。再者，从各类自然保护地申报设立的条件和环保督查中反映出来的问题两方面入手分析了自然保护地的自然资源保护管理现状，从国家公园体制试点采取的措施出发分析了目前的改革探索，并提炼出自然保护地自然资源资产产权制度存在的四大问题，即自然资源资产产权的界定和要求较局限、自然资源所有权行使人虚位、公权与私权的利益协调机制不健全、改革探索中物权途径面临制度障碍。最后，从自然资源资产产权制度设计的角度提出了改革的4个方向。     

Existence of a competitive equilibrium in a one sector growth model with heterogeneous agents and irreversible investment

Summary. We prove existence of a competitive equilibrium in a version of a Ramsey (one sector) model in which agents are heterogeneous and gross investment is constrained to be non negative. We do so by converting the infinite-dimensional fixed point problem stated in terms of prices and commodities into a finite-dimensional Negishi problem involving individual weights in a social value function. This method allows us to obtain detailed results concerning the properties of competitive equilibria. Because of the simplicity of the techniques utilized our approach is amenable to be adapted by practitioners in analogous problems often studied in macroeconomics. Received: September 13, 2001; revised version: December 9, 2002 RID="*" ID="*" We are grateful to Tapan Mitra for pointing out errors as well as making very valuable suggestions. Thanks are due to Raouf Boucekkine and Jorge Duran for additional helpful discussions. We also thank an anonymous referee for his/her helpful comments. The second author acknowledges the financial support of the Belgian Ministry of Scientific Research (Grant ARC 99/04-235 “Growth and incentive design”) and of the Belgian Federal Goverment (Grant PAI P5/10, “Equilibrium theory and optimization for public policy and industry regulation”). Correspondence to: C. Le Van     

Price–Cost Margins and Structural Change: Sub-Contracting within the Salmon Marketing Chain

Some recent studies have benefited from advances in time series econometrics in order to evaluate price transmission mechanisms along the marketing chain. Due to the length of time series, structural changes may affect the evaluation of price–cost margins. In the case of the fresh salmon trade between Norway and France, the gross margin between producers and retailers has changed in level between January 1988 and December 1999. This article accurately identifies the date of a structural change using a range of recent ADF testing procedures (Gregory–Hansen tests, forward and backward recursive tests), before looking for the causes of the change through a survey. Two major factors can be identified: the product form and the marketing channel. Interestingly, both the increasing level of processing and the development of supermarket chains have resulted in a new role for the intermediaries, shifting from mere commercial intermediation to sub‐contracting for the big retailers.     

一种项目采购模式的博弈分析

本文试图用经济学理论 (主要是博弈与信息经济学的理论 )来分析目前工程项目建设中采用的一种工程设备、材料的采购模式。文章首先提出这种模式的内容与特征 ,然后就制度内各参与方 (主要为业主、承包商、供货商 )之间的博弈进行分析 ,分不完全信息博弈、完全信息博弈两种情况来分析这种采购制度下达到的均衡。     

The price relationship between organic and non-organic vegetables in the U.S.: evidence from Nielsen scanner data

This study investigates price relationships between organic and conventional carrots, tomatoes, and lettuce in the U.S. utilizing Nielsen scanner data from 2006–2015. We employ a threshold vector error correction model (TVECM), threshold vector autoregressive model (TVAR), and threshold cointegration test to test whether market integration exists between organic and conventional vegetables as well as the existence of asymmetric price transmission. The results find positive long-run relationships between organic and conventional prices of carrots and tomatoes and show the existence of asymmetric price transmission in price pairs of lettuce and tomatoes. Our findings suggest that the price relationship between organic and conventional vegetables varies by characteristics, such as shelf life, volatility in the price premium, and substitutability.     

Some results about averaging in stochastic approximation

The paper presents some results concerning the averaging approach in a general linear regression model in one dimension under suitable conditions about the martingale structure of errors. At first asymptotics of the primary and averaged estimators are discussed. Then it is shown that variances of estimators can be consistently estimated by appropriate integrated squared deviations functionals. Finally applications to the construction of confidence regions are considered.     

The Impact of Acquisitions on Operating Performance: Some Australian Evidence

This study investigates the impact of acquisitions on the operating performance of Australian firms. For a sample of 36 Australian acquisitions occurring between 1986 to 1991 inclusive, and using matched firms to control for industry and economy-wide factors, the results based on four accrual and four cash flow performance measures show that corporate acquisitions do not lead to significant improvements in post-acquisition operating performance. The consistency of the results with the agency, the hubris and the financial motivation hypotheses suggests that corporate acquisitions in Australia may be undertaken for other than synergistic reasons. The results assist in explaining inconsistent findings reported in the literature.     

Some Further Results on the Tempered Multistable Approach

This article provides new results on the tempered multistable approach. After a preliminary section recalling the main definitions, we show the correspondence between a series representation and a characteristic function representation for asymmetrical field-based tempered multistable processes and for asymmetrical independent increments tempered multistable processes. We also show that both processes are semimartingales, which is a convenient property in finance. Next, we study the structure of autocorrelations that is conveyed by this approach. Finally, we provide an illustration showing the term structures of Value-at-Risk that can be obtained with this model.     

Carbon taxes and the double dividend hypothesis in a recursive-dynamic CGE model for Spain

A carbon tax is potentially a policy that can reduce CO₂ emissions and mitigate climate risks, at lowest economy-wide costs. We develop a dynamic CGE model for Spain to assess the economic and environmental effects of a carbon tax, and test the double dividend (DD) hypothesis. We simulate the impact of three carbon taxes: €10, €20 and €30 per ton of CO₂. For each tax, four ‘revenue recycling’ scenarios are examined: a reduction of taxes on capital, on labor, on value-added tax, and a scenario in which revenues are not recycled. We find a DD for taxes of €10/ton and lower, within five to seven years of implementation. We estimate an annual CO₂ emissions reduction of around 10% with this tax. Under some circumstances, the DD can be achieved for a tax of €20/ton. In any case, recycling revenues to cut pre-existing taxes reduces costs of imposing carbon taxes.     

Creation of models for calculation of coefficients of terrain passability

Quality & Quantity - The content of this article is a paper about a complex mathematical model of terrain passability which respects geographical and meteorological conditions in terrain and...