Bread or justice - Land restitution and investments in Montes de Maria,Colombia

In 2011, Colombia started a legal land restitution process whereby government institutions help internally displaced people (IDPs) reclaim land dispossessed after 1991 through the violent conflict involving the communist guerilla, paramilitaries and the army. The designated land courts normally covers voluntary sales at the going market price at the time of dispossession, presuming buyers took advantage of the IDPs’ need for money and their low expectations of returning from their current sites of refuge. We study the rise and fall of a commercial cassava operation that started to buy land from IDPs openly in the Montes de María region on Colombia’s Caribbean coast after peace returned in 2007. After losing several land restitution court cases, the company shifted from dairy cattle that required high investments to the less demanding, but also less productive, buffalo to minimize losses in case of future successful restitution claims. The land restitution law will probably be extended beyond the initial 2021 limit due to slow progress, thereby perpetuating the insecure property rights situation that hinders investments in agriculture.     

China’s megaregion policy: Performance evaluation framework,empirical findings and implications for spatial polycentric governance

Megaregion has emerged as a new dimension of global urbanization. A megaregion approach based on polycentric strategy is deemed to enhance regional economic competitiveness. Numerous studies have highlighted the economic benefits, celebrated the spill-over effects, and outlined the creative potentials of contemporary megaregion policies in different nations worldwide. However, further policy instruments require the knowledge about the achievement and failure of megaregion policies that seek for spatial, economic, social, and environmental efficiency and sustainability. This paper introduces China’s megaregion policy and proposes an analytical framework for performance evaluation from four principle domains (rational urban growth, economic development, social equity, environmental protection) at three levels (internal collaboration, integral development, and overall development). Using a case of the Megaregion around Hangzhou Bay (MAHB), we find very limited success of China’s megaregion policy. In particular, the megaregion policy only accomplishes the economic goal, and fails to achieve the goals of rational urban growth, environmental protection, and social equity. A series of mechanism based regressions are established and show that the implementation duration of megaregion policy: (1) associates positively with the economic growth; (2) relates negatively to social equity and urban rational growth; and (3) has no significant relationship with improved environmental quality. Institutional fragmentation, no unified spatial planning, and inadequate legislation at megaregional level are the underlying causes of the expected performances within the policy context of governance itself. We finally propose some possible solutions and discuss the implications for spatial polycentric governance. The demonstrated methodological framework can be applicable to other megaregions around the world. This paper is thus believed to provide some new insights for land use policy.     

Towards a sustainable capacity expansion of the Danish biogas sector

Promotion of bioenergy production is an important contemporary topic around the world. Vast amounts of research are allocated towards analysing and understanding bioenergy systems, which are by nature multi-faceted. Despite a focus on the deployment of multi-criteria decision-making (MCDM) methods for planning of bioenergy systems, only little research has addressed the location component of bioenergy facility planning. In this paper the authors develop a model for sustainable capacity expansion of the Danish biogas sector allowing for an identification and prioritization of suitable locations for biogas production. The model builds on a framework for spatial planning and decision making through the application of spatial multi-criteria evaluation (SMCE). The paper is structured around a case study including four Danish municipalities in order to demonstrate the power of the spatial multi-criteria evaluation model. The model allows a two level comparison of suitability, within municipalities as well as between municipalities. Criteria weights for generation of alternatives are obtained through an analytical hierarchy process (AHP) analysis, carried out among a group of Danish central governmental decision makers. We find that resource and production economic criteria are given highest priority followed by environmental and social criteria. In all four case study municipalities, the identified alternatives are compared through incorporating economic, environmental and social criteria. It is found that 4–6% of the municipal area is suitable for biogas facility location and among the best performing sustainable locations the potential of reducing overall production costs is 3% as compared with current biogas plants. The results of this paper can provide support to central governmental decision makers, regarding regional allocation of subsidies in the country. Likewise local decision makers can obtain important information for planning and decision support, allowing for a more inclusive and transparent planning procedure.     

动态分区存储管理方式的模拟

采用Java语言展现动态分区中的两种分配算法——首次适应算法和最佳适应算法,以及内存的回收过程的动态模拟实现。该模拟实验可以帮助学生理解内存管理的分配算法,并激发学生学习的兴趣。     

Efficiency,total factor productivity and returns to scale in a sustainable perspective: An analysis in the European Union at farm and regional level

For global sustainability it is imperative to find a balance across the three main components of sustainable development which are the economic, social and environmental aspects. However, it is not a simple task to make these contexts compatible, usually because of economic pressures which transform them into opposed objectives. This framework occurs across several dimensions within society and the economy, where the agricultural sector is not an exception. The objective of this study is to analyse the efficiency, total factor productivity and returns to scale in an economic, social and environmental perspective in farms of the European Union (EU) regions through Data Envelopment Analysis (DEA) approaches. The research concerning the returns to scale will be complemented by the Keynesian models. Data obtained from the European Union Farm Accountancy Data Network (FADN) was considered. The results show that in maintaining or improving the levels of production in farms, it is often possible to greatly reduce, in some cases, the consumption of fertilizers and crop protection products. On the other hand, from a social perspective, some European Union regions are more generous in the salaries paid to farming workers and absorb more labour, which in a European context of unemployment, may be an interesting way to realistically look at and be engaged in the agricultural planning in a sustainable way, founding a balanced trade-off among the economic, social and environmental dimensions.     

Evolution of the international air transportation country network from 2002 to 2013

In this research, we analyze the evolution of the international air transportation country network from 2002 to 2013 with two perspectives: The network’s physical topology and the functional network with traffic information. Our analysis shows that the network is scale-free and has the small-world property. The evolution of triadic properties suggests that the network gears towards symmetric, transitive closure. We find that United States, Great Britain, and France are critical from both perspectives; Surprisingly, South Africa is particularly critical from topological point of view. Furthermore, topological and functional criticality are highly correlated to the GDP of a country.     

Request selection and exchange approach for carrier collaboration based on auction of a single request

This paper addresses the request selection and exchange problem in the carrier collaboration process with limited sharing of carrier’s request information. A framework including two decision makers, carrier and coordinator, is constructed and its collaboration process is described. In this framework, two request selection models for the carriers are established. In addition, a request exchange method for the coordinator is proposed and four profit allocation strategies are discussed. Compared with other four approaches, simulation results show that the proposed approach is effective and efficient.     

The composite iteration algorithm for finding efficient and financially fair risk-sharing rules

We consider the problem of finding an efficient and fair ex-ante rule for division of an uncertain monetary outcome among a finite number of von Neumann–Morgenstern agents. Efficiency is understood here, as usual, in the sense of Pareto efficiency subject to the feasibility constraint. Fairness is defined as financial fairness with respect to a predetermined pricing functional. We show that efficient and financially fair allocation rules are in one-to-one correspondence with positive eigenvectors of a nonlinear homogeneous and monotone mapping associated to the risk sharing problem. We establish relevant properties of this mapping. On the basis of this, we obtain a proof of existence and uniqueness of solutions via nonlinear Perron–Frobenius theory, as well as a proof of global convergence of the natural iterative algorithm. We argue that this algorithm is computationally attractive, and discuss its rate of convergence.     

Implications of land use transitions on soil nitrogen in dynamic landscapes in Tanzania

Land use transitions are rated among the leading sources of greenhouse gas emissions in the tropics. They significantly challenge the functioning of ecosystems and affect multi-temporal stability of greenhouse gases such as N₂O and soil properties. Studies on dynamics in nitrogen balances are essential in understanding greenhouse gas emissions such as N₂O and to manage their impacts on productivity. In this study, multi-temporal Landsat images (1975, 1995 and 2012) were classified to determine land use transitions and potential drivers. The classified images were categorized into degraded and non-degraded lands and eighty sampling plots generated within the entire study area. Soil samples were then collected at 0–15, 15–30 and 30–60 cm depths on each plot and soil nitrogen determined. A regression analysis was developed to determine the influence of forest and grassland degradation on soil nitrogen. Results indicated a significant change in major land use and land cover types. Specifically, there was a decrease in areas covered by forests, woodland and grassland, however, area covered by less dense forest increased. Results also indicated variability in mean nitrogen content between degraded and non-degraded areas and depths. Furthermore, levels of degradation influence nitrogen content up to a soil depth of 30 cm. The present study is relevant in the detailed assessment of the extent of damage and threats posed to biodiversity hotspots in sub-Saharan Africa. These results are transferable to other parts of the world characterized by dynamic ecological transformation.