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Pesticide overuse has resulted in serious ecological problems. Agricultural extension services play a key role in influencing farmers’ pesticide use. China has the world's largest public agricultural extension system, which has experienced a twisting path of reforms over the past four decades. However, there is little empirical evidence regarding the effects of agricultural extension services in the post-reform era since the mid-2000s. This study examines the effect of agricultural extension services in the post-reform era on pesticide use in China, using survey data of 1963 rice farmers in 2016 and 2018. Our results indicate that only 22.5% of surveyed farmers adopted agricultural extension services. After addressing the self-selectivity issue, the treatment effects model revealed that agricultural extension services in the post-reform era resulted in a 3.01 kg/ha reduction in total pesticide use, a 0.86 kg/ha reduction in application rate of active ingredients, and a 250 CNY/ha reduction in pesticide expenditure related to rice production. Our findings provide sound evidence that agricultural extension services in the post-reform era can result in a reduction in pesticide use for rice production. More effective efforts should be made to reinforce the provision of agricultural extension services and encourage farmers to adopt these services.

Pesticide overuse has resulted in serious ecological problems. Agricultural extension services play a key role in influencing farmers' pesticide use. China has the world's largest public agricultural extension system, which has experienced a twisting path of reforms over the past four decades. However, there is little empirical evidence regarding the effects of agricultural extension services in the post-reform era since the mid-2000s. This study examines the effect of agricultural extension services in the post-reform era on pesticide use in China, using survey data of 1963 rice farmers in 2016 and 2018. Our results indicate that only 22.5% of surveyed farmers adopted agricultural extension services. After addressing the self-selectivity issue, the treatment effects model revealed that agricultural extension services in the post-reform era resulted in a 3.01 kg/ha reduction in total pesticide use, a 0.86 kg/ha reduction in application rate of active ingredients, and a 250 CNY/ha reduction in pesticide expenditure related to rice production. Our findings provide sound evidence that agricultural extension services in the post-reform era can result in a reduction in pesticide use for rice production. More effective efforts should be made to reinforce the provision of agricultural extension services and encourage farmers to adopt these services. [ABSTRACT FROM AUTHOR]

Direct seeding has been widely adopted in rice production due to its advantages of water- and labor-saving characteristics in China and other countries. This study aims to examine the effects of farmers' adoption of direct seeding on the yield and fertilizer use in rice production in China. Using survey data of 1002 rice farmers in the Yangtze River Basin in China, the endogenous switching regression model is used to address the self-selectivity bias from both observed and unobserved heterogeneity. The results show that about 79% of surveyed farmers adopted direct seeding in rice production. After addressing the self-selectivity bias, the adoption of direct seeding increased rice yield among the adopters by 3.65%, and would have increased rice yield among the non-adopters by 1.54% if direct seeding had been adopted. In addition to its positive effect on rice yield, however, the adoption of direct seeding was also found to increase fertilizer use among the adopters by 19.84%, and would have increased fertilizer use among the non-adopters by 37.75% if direct seeding had been adopted. Moreover, farmers' adoption of direct seeding exerted heterogeneous effects on rice yield and fertilizer use in terms of farm size and location. [ABSTRACT FROM AUTHOR]

Solution‐processed organic memristors are promising ingredients to realize smart wearable electronics including neural networks. In organic memristors, tunable functionality of materials allows for realizing bio‐realistic neuromorphic electronics in the view point of the mechanical and electrical characteristics. However, it is challenging to achieve high‐density crossbar arrays of organic memristors due to undesirable sneak currents arising from unselected cells. For inorganic systems, considerable effort has been made to fabricate practical arrays by employing external components to suppress sneak current. By contrast, in organic memristors, it is barely possible to achieve practical systems due to the solvent orthogonality limiting the integration of the devices. Herein, an unprecedented structure of organic memristors with high self‐selectivity is developed to realize practical crossbar arrays. In the developed memristor, the self‐selective characteristics are achieved by systematically engineering the conductive nanofilament diffusion in the polymer. The maximum size of the memristor arrays is found to be more than 1 Mbits, and the neural networks based on the developed device showed reliable recognition performance similar to ideal software systems. This novel concept of developing the organic memristor with high self‐selectivity will open a new platform for realizing next‐generation flexible memory and practical neuromorphic systems linked to artificial intelligence. [ABSTRACT FROM AUTHOR]

Direct seeding has been widely adopted in rice production due to its advantages of water- and labor-saving characteristics in China and other countries. This study aims to examine the effects of farmers’ adoption of direct seeding on the yield and fertilizer use in rice production in China. Using survey data of 1002 rice farmers in the Yangtze River Basin in China, the endogenous switching regression model is used to address the self-selectivity bias from both observed and unobserved heterogeneity. The results show that about 79% of surveyed farmers adopted direct seeding in rice production. After addressing the self-selectivity bias, the adoption of direct seeding increased rice yield among the adopters by 3.65%, and would have increased rice yield among the non-adopters by 1.54% if direct seeding had been adopted. In addition to its positive effect on rice yield, however, the adoption of direct seeding was also found to increase fertilizer use among the adopters by 19.84%, and would have increased fertilizer use among the non-adopters by 37.75% if direct seeding had been adopted. Moreover, farmers’ adoption of direct seeding exerted heterogeneous effects on rice yield and fertilizer use in terms of farm size and location.

Return migrants play an increasingly important role in agricultural production in China and other developing countries. However, the effect of rural–urban migration experience on farmers’ arable land use remains unclear. This study aims to fill this gap using data from a survey of 2293 farmers consisting of 586 return migrants and 1707 non-migrants in China. We employ the treatment effects model to account for the self-selectivity of rural–urban migration experience arising from observable and unobservable factors. The results show that after accounting for the self-selectivity bias, the rural–urban migration experience significantly increases farmers’ arable land use by 22%. Meanwhile, the positive effect of rural–urban migration experience on arable land use differs by farmers’ age group and region. While rural–urban migration experience increases arable land use for farmers aged below 65 years old by 29%, it shows no significant effect on arable land use for farmers aged 65 years old and above. In addition, there is a positive relationship between rural–urban migration experience and arable land use in Shaanxi, Shandong, and Zhejiang. However, there is no significant effect of rural–urban migration experience on arable land use. On such a basis, we discuss several important implications for policies related to arable land use in China.

We provide exact relations giving the probability of individual and coalitional manipulation of three specific social choice functions (Borda rule, Copeland rule, Plurality rule) in three-alternative elections when the notion of self-selectivity is imposed. We use each type of tie-breaking rule in the case of three-candidate election in order to make the results more robust. Analyzing our probabilities, we can point out that the probability of individual and coalitional manipulation tend to vanish significantly when the notion of self-selectivity is imposed. [ABSTRACT FROM AUTHOR]

Examination on firm performance subsequent to a chosen event is widely used in finance studies to analyze the motivation behind managerial decisions. However, results are often subject to bias when the self-selectivity behind managerial decisions is ignored and unspecified. This study investigates a unique corporate event of initial public offering (IPO) withdrawal, where a firm's subsequent likelihood of bankruptcy is specified in a system of switching hazard models, and the expected difference in post-IPO and postwithdrawal survival probabilities serves as a 'feedback' on a firm's decision to cancel its offering. Our Bayesian inference procedure generates strong evidence that incidence of withdrawal unfavorably affects the subsequent performance of a firm, and that the 'feedback' is an important determinant in managerial decisions. The econometric and statistical model specification and the accompanying estimation procedure we used can be widely applicable to study self-selective corporate transactions. [ABSTRACT FROM AUTHOR]

When choosing a voting rule to make subsequent decisions, the members of a committee may wish this rule to be self-selected when it is the object of a choice among a menu of different possible voting rules. Such concepts have recently been explored in Social Choice theory, and a menu of voting rule is said to be stable if it contains at least one self-selective voting rule at each profile of preferences on voting rules. We consider in this article the menu constituted by the three well-known scoring rules {Borda, Plurality, and Antiplurality}. Under the Impartial Culture assumption, which proposes an a priori model to estimate the likelihood of the profiles, we will derive a probability for the stability of this triplet of voting rules. [ABSTRACT FROM AUTHOR]

Objective: Two alternative selectivity correction methods have been widely applied in the health economics literature: the sample selection model (SSM) and the multipart model (MPM). The difference between these two approaches results from their initial assumptions about the distribution of error terms. Because the distributional assumptions cannot be theoretically verified, the usefulness of the methods can only be evaluated by real world comparison. This article reviews and empirically tests the two alternative selectivity correction methods to give a reality-based evaluation. Methods: Using a randomized sample of patients as the “gold standard,” the SSM and MPM are applied to a nonrandomized sample of patients with an identical set of dependent and independent variables. By comparing the actual estimates of the two methods, we evaluate the robustness of the two approaches. Results: The results show that neither method is empirically robust in replicating the results of the randomized trial. There is no consistent pattern in the coefficients from either selectivity-correction method for replicating the coefficients in the randomized sample. Conclusions: Researchers should be cautious in applying these correction methods, and any conclusions based on these approaches may need to be qualified. [ABSTRACT FROM AUTHOR]

This paper introduces a new notion of consistency for social choice functions, called self‐selectivity, which requires that a social choice function employed by a society to make a choice from a given alternative set it faces should choose itself from among other rival such functions when it is employed by the society to make this latter choice as well. A unanimous neutral social choice function turns out to be universally self‐selective if and only if it is Paretian and satisfies independence of irrelevant alternatives. The neutralunanimous social choice functions whose domains consist of linear order profiles on nonempty sets of any finite cardinality induce a class of social welfare functions that inherit Paretianism and independence of irrelevant alternatives in case the social choice function with which one starts is universally self‐selective. Thus, a unanimous and neutral social choice function is universally self‐selective if and only if it is dictatorial. Moreover, universal self‐selectivity for such functions is equivalent to the conjunction of strategy‐proofness and independence of irrelevant alternatives or the conjunction of monotonicity and independence of irrelevant alternatives again. [ABSTRACT FROM AUTHOR]