Critical current density: Measurements vs. reality

Different experimental techniques are employed to evaluate the critical current density (Jc), namely transport current measurements and two different magnetisation measurements forming quasi-equilibrium and dynamic critical states. Our technique-dependent results for superconducting YBa 2Cu3O7 (YBCO) film and MgB2 bulk samples show an extremely high sensitivity of Jc and associated interpretations, such as irreversibility fields and Kramer plots, which lose meaning without a universal approach. We propose such approach for YBCO films based on their unique pinning features. This approach allows us to accurately recalculate the magnetic-field-dependent Jc obtained by any technique into the Jc behaviour, which would have been measured by any other method without performing the corresponding experiments. We also discovered low-frequency-dependent phenomena, governing flux dynamics, but contradicting the considered ones in the literature. The understanding of these phenomena, relevant to applications with moving superconductors, can clarify their dramatic impact on the electric-field criterion through flux diffusivity and corresponding measurements. © Copyright EPLA, 2013

Why the Uncertain Term Occurs in the Farmland Lease Market: Evidence from Rural China

Urbanization and aging of the agricultural population lead to the insufficient supply of agricultural labor and land being idle in rural China, calling for the farmland lease market to maintain sustainable and efficient use of farmland. However, rural households tend to agree on an uncertain term for farmland leasing in/out, which leads to low efficiency and land loss in agriculture. Therefore, using the survey data collected from 2704 rural households and a logistic regression model, we examine the effects of risk faced by the rural households on the likelihood of the uncertain term for farmland leasing. Results reveal that a large share of labor with low education and high income increase the likelihood of an uncertain term for farmland leasing out activities, while a high disaster frequency, a high education of household and a high share of agricultural income increase the probability of an uncertain term for farmland leasing in activities. Additionally, leasing farmland to/from relatives or neighbors, informal contracts, low rent and the lack of pension insurance also increase the likelihood of the uncertain term for farmland leasing out/in activities. Findings suggest that more attention should be paid to education, agricultural insurance and social security system in rural areas

Farmland Lease, High-Rent Threat, and Contract Instability: Evidence from China

We develop a game theoretical model to understand the stability problem in the farmland lease contract in China where most land-owners are small landholders. When these small land-owners lease their land to large landholders, they take a high-rent-threaten strategy that can result in contract instability. Results obtained from doubly-robust estimation used on randomly selected interview data from 1611 households in nine provinces in China indicate that, (1) compared to those land-owners who transfer the farmland to the small landholders, the land-owners who transfer the farmland to large landholders will have a higher 46.57% possibility to ask for higher rent in the contract duration (high-rent-threaten strategy); (2) land-owners’ high-rent-threaten strategy will increase 4.49% possibility of the contract breaks; (3) in general, compared with those contracts that the transfer objects are not large landholders, the contracts that the transfer objects are large landholders has a 6.81% higher possibility of breakdown; (4) if we isolate the influence of land-owners’ high-rent-threaten strategy on the contract break, the contracts that the transfer objects are large landholders still has a 5.65% higher possibility of breakdown. The empirical results entail that, comparing to the stable farmland lease contract between two small farmers, contract instability can arise endogenously when large landholders lease farmlands. We conclude that a suitable rent control regime may be necessary to promote a large scale farmland transfer in China

Do Chinese farmers benefit from farmland leasing choices? Evidence from a nationwide survey

Using China Family Panel Studies (CFPS), this study investigates factors associated with the choice of farmland leasing strategies and the impact of leasing options on farm performance. Particular attention is given to off-farm employment and farm subsidies. Additionally, the study applies a selectivity-based approach to assess the relationship between farmland leasing choices and farm businesses’ performance. Off-farm employment, older and educated operators, large farms and old-age pension plans increase the likelihood of leasing out farmland. Part-time off-farm employment, grain subsidies and mechanised farms increase the likelihood of leasing in farmland. Finally, the selectivity correction terms in the value of crop production are significantly negative in the choices of farmland leasing, indicating the presence of sample selection effects. Accounting for selectivity is essential to ensure unbiased and consistent estimates

The Impact of Dialect Diversity on Rent-Free Farmland Transfers: Evidence from Chinese Rural Household Surveys

The rent-free farmland transfer that exists widely in China’s rural areas is a topic worthy of attention. Particularly, the regional heterogeneity of its occurrences implies regional cultural heterogeneities. Using local dialects to proxy regional cultural features, this study applies econometric methods to examine the impacts of dialect diversity on rent-free farmland transfers. It also considers possible mechanisms through a mediation analysis, based on a combined two-year rural household survey dataset from the Guangdong and Jiangxi Provinces in 2015 and 2016. Robust estimation results reveal that dialect diversity increases the probability of rent-free farmland transfers at the household and village levels. According to the mediation analysis, dialect diversity influences villages’ farmland abandonment, rural farmland market development, and the flexibility of farmland transfer contracts, which further affects rent-free farmland transfer. Rent-free farmland transfer depends on social trust and contracts’ self-fulfilling advantages. Therefore, cultural and traditional factors should be taken into consideration, which would form beneficial interactions between the selections of rural farmland institutional arrangement and land rights policy implementations

Evaluating Low-Carbon City Development in China: Study of five national pilot cities

This chapter develops a low-carbon city evaluation system to assess the performance of five pilot low-carbon city projects in China. Section two discusses and introduces the principles and the main indictors for evaluating the performance of low-carbon cities, including the methodology used herein. Section three uses the indicators to evaluate the performance of five national pilot low-carbon cities in China. The final section summarises the findings and provides policy suggestions based on our findings

The Influence of Farmland Differentiation on the Implementation of Land Titling in Villages: Evidence from China

We develop a theoretical model to understand the progress of Land Titling initiated based on the Household Responsibility System in China since 1979. Land Titling has heterogeneous progress across different villages. We argue that farmers' resistance could hinder the implementation of the land title, but the homogenization of farmland quality and the farmers’ private agricultural investments in the village can help farmers to accept the policy in the following mechanisms. The homogenization of farmland quality can reduce the unfair cost of Land Titling; also the farmers’ private agricultural investments can evoke the need of farmers to protect property rights in the village where only partial farmers have engaged in agricultural investment. The theoretical model developed in the paper is supplemented by empirical analyses of farm household data collected from Guangdong provinces in China. We analyze data using Random Effect Generalized Ordered Probit models. Results indicate that, (1) the difference degree of farmland quality (traffic and fertility) within a village has a significant negative effect on the process level of Land Titling in this village; (2) the difference degree of farmers’ private agricultural investment (irrigation and mechanical usable proportion) within a village has a significant positive effect on the process level of Land Titling in this village; (3) as the Land Titling contains 5 procedures to implemented, the above two important factors mainly effect the implementation of the procedures which are about the titled land need to be recognized by the whole village community