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PurposeChina's economy has transformed from a high-speed growth phase to a high-quality development phase. The agriculture sector has grown substantially since the economic reform in 1978. Considering the five-year plan (FYP) as a collection of policies, this study explores the relationship between the FYP and agricultural total factor productivity (TFP).Design/methodology/approachThis study uses 31 provincial-level panel data of the five FYPs from 1996 to 2020. The data envelopment analysis (DEA) is used to compute Malmquist productivity indexes. The authors analyze the temporal and spatial changes and convergences of China's agricultural TFP, and investigate the impact of economic planning on China's agricultural TFP and its regional difference.FindingsThere is a slow but upward growth trend in China's agricultural TFP. The technical change has played a leading role in the growth of China's agricultural TFP. The agricultural TFP of all provinces has shown a “catch-up” effect and is developing toward their respective steady-state levels. The regional difference in productivity growth among the eastern, central and western regions exists. Test results show that the FYP has a positive effect on the agricultural TFP, and the effect has obvious regional heterogeneity. The FYP also plays a positive role in the gross value of agricultural output, and the impact effect is greater than that on the improvement of agricultural productivity.Originality/valueThere are many forms of industrial policy in China, among which the FYP is the guiding document of industrial policy, which makes a systematic plan for industrial development in the subsequent five years. The development objectives, guidelines and overall deployment for agriculture in the FYP not only describe the general context of China's agricultural development but also show the key ideas of agricultural development. Therefore, this study explores its impact on agricultural quality development from the perspective of FYP. The results provide evidence for examining the governance performance of the government and the objective evaluation and restraint of the FYP. As agriculture moves toward the stage of high-quality development, the Chinese government should strengthen the critical guiding role of the FYP and pay attention to quality indicators such as technical progress, efficiency improvement and regional coordination in the formulation of the FYP.

This research qualitatively explored user preferences for an app-based mHealth approach to support HIV self-testing and linkage to HIV prevention or care services developed for men who have sex with men (MSM) in China. We conducted 12 online focus group discussions with MSM participants (N = 48) about their preferences for using an app to meet their HIV self-testing and service linkage needs. Data were examined using thematic analysis. Participants specified four domains to align program delivery with their preferences for app-based intervention: (1) expanding HIV prevention/antiretroviral therapy concepts beyond basic knowledge; (2) enhancing the style and presentation of app-based messages; (3) incorporating interactive and dynamic app-engagement features; and (4) creating a “one station” app that covers the continuum of HIV services. Given the changing landscapes of HIV knowledge and community/user preferences for app-based interaction, findings underscore how engagement with end-user participants is essential to optimize mHealth interventions for HIV.

BACKGROUND In China, unprotected sex among men who have sex with men (MSM) is the primary route of HIV infection among young people. Chengdu is a hotspot for reported HIV cases among young people nationwide. Extensive use of geosocial networking (GSN) smartphone apps has dramatically changed the pattern of sexual practice among young MSM (YMSM). However, data on HIV incidence and the risk practice of GSN app-using YMSM are still opaque. OBJECTIVE This study aims to analyze and understand the HIV incidence and its risk factors among gay GSN app-using YMSM in Chengdu. METHODS An open cohort study was conducted among 18-24 years old YMSM through a gay GSN smartphone app in Chengdu, China, from July 2018 to December 2020. Every participant completed an online questionnaire on sociodemographic characteristics, sexual behaviors, and other related status; made a reservation for HIV testing online, then tested at the designated offline testing site. At least one additional HIV test was taken via the app during the study period, and participants were evaluated at the end of the study, or at the time of HIV seroconversion. By dividing the sum of the observed HIV seroconversions by the observed person-years, HIV incidence was calculated and compared between the student and non-student MSM. Univariate and multivariate (cox proportional hazards regression) analyses were used to discuss the risk factors for HIV new infections. RESULTS In the cohort, 24 seroconversions occurred among 625 YMSM who took at least two HIV tests from app during the study period, contributing 505 observed person-years (PY). The HIV incidence rate were 4.75 [95% confidence interval (CI): 2.89-6.61]/100 PY, 3.60 (95%CI: 1.27-5.93)/100 PY, and 5.88 (95%CI: 2.97-8.79)/100 PY, among all MSM, student MSM and non-student MSM, respectively. In addition, the HIV incidence was 11.11 (95%CI: 4.49-17.73)/100 PY among those who had lived locally for 6 months or less, and 7.14 (95%CI: 1.52-12.77) /100 PY among those who had senior high school or less education. More than two sexual partners [adjusted hazard ratio (aHR) = 3.63, 95% CI: 1.08-12.23] in the preceding 6 months was a risk factor for HIV new infections. Those who reported consistent condom use for anal sex (aHR =0.38, 95% CI: 0.16-0.88) and insertive anal sex only (aHR = 0.10, 95% CI: 0.01-0.75) in the preceding 6 months were protective factors for new HIV infections. CONCLUSIONS The rate of HIV new infection among YMSM who active in GSN smartphone app is high, especially among migrant non-student MSM. Targeted interventions on GSN smartphone app should be implemented to provide demand-adapted prevention and services to reduce the threat of HIV.

Using data from the China Health and Nutrition Survey, we examine the effect of the number of siblings on dietary quality with a sample of 2–12-year-old children in China. We use instrumental variables to address the potential endogeneity of the number of siblings. We show that the effect of the number of siblings on children’s dietary quality is significantly negative. Child dietary diversity score will decrease by 0.274 with one more siblings. In terms of children’s nutrition, the intake of fat and protein also significantly decrease. A robustness check using the fixed effects models also validates our findings that child quantity–quality trade-off is apparent in Chinese families.

Using data from the China Household Finance Survey, we investigate the relationship between family involvement and the subjective well-being (SWB) of the self-employed. Instrumental variables are u...

Using data from three waves of the China Health and Retirement Longitudinal Study, this study identifies a causal effect of the distance adult children reside from their parents on the mental health of the rural elderly. We use panel correlated random effect methods with instrumental variables to address potential confounding effects of reverse causality and unobserved omitted variables. We find that the impact of the distance adult children live from their parents on parental mental health exhibits an inverted ‘U-shaped’ pattern that first increases (good) and then slowly decreases (poor). Further analysis finds that the effect of the residence distance on the mental health of rural elderly has statistically significant differences by gender of the elderly. Submitted version

The first-born child's quality may be affected by a younger sibling in a family based on the quantity-quality trade-off theory. Using data from the China Health and Nutrition Survey, we examine the causal effect of having a younger sibling on the health of the first-born child aged 2–12 in China. We use instrumental variables to address the potential endogeneity of having a younger sibling in the extended regression model. We found that having a sibling significantly decreases the height-for-age z-scores of the first-born child, and the greater age gap may alleviate the effect. Further analysis shows that the effect is particularly strong for the pre-school child under 6 years old and the child in a low-income family or the rural area. A sibling influences the first-born child's health by dietary pattern, physical activities, and medical services utilization. The robustness checks, based on individual fixed-effects model and propensity score matching approach, validate our findings, which suggest that future preventive intervention on the deterioration of first-born child’s health during the implementation of the universal two-child policy.

Background Given the rampant HIV epidemic among men who have sex with men (MSM) in Chengdu, southwest China, Treat All policy, defined as immediate antiretroviral therapy (ART) initiation after HIV diagnosis, was implemented since 2014. Real-world research evaluating impacts of immediate ART on HIV epidemics is needed to optimize policy-making as national and international guidelines have been lowering ART eligibility threshold. The purpose of this study is to: assess temporal trends of the HIV epidemic and impacts of Treat All policy among MSM; and lay foundation for HIV-related policy evaluation using longitudinal routine data from health information systems. Methods Data used in this study were HIV sentinel seroprevalence, annual reported HIV cases and ART coverage rate among MSM in Chengdu from 2008 to 2018, derived from national HIV/AIDS information system. Temporal trends of the HIV epidemic were described using Joinpoint Regression Program. Interrupted time-series method was deployed to evaluate Treat All policy. Results HIV sentinel seroprevalence rose from 11.20% in 2008 to 17.67% in 2013 and Annual Percent Change (APC) was 8.25% (95% CI − 2.40%, 20.07%), then decreased to 5.17% in 2018 (APC = − 19.63%, 95% CI − 27.54%, − 10.86%). Newly reported HIV cases increased from 168 cases in 2008 to 1232 cases in 2015 (APC = 26.99%, 95% CI 21.32%, 32.93%), and reduced to 1014 cases in 2018 (APC = − 8.80%, 95% CI − 18.45%, 2.01%). ART coverage rate has been climbing from 11.11% in 2008 to 92.29% in 2018 and Average Annual Percent Change was 16.09% (95% CI 11.76%, 20.59%). Results of interrupted time-series models showed that compared to an annual increase of 0.87% during pre-policy period, there was a decline of 3.08% (95% CI − 0.0366%, − 0.0250%) per year of HIV sentinel seroprevalence since 2014; and compared to an annual increase of 116 cases before 2014, there was an annual drop of 158 newly reported HIV cases (95% CI − 194.87%, − 121.69%) during the post-policy period. Conclusions Immediate ART after HIV diagnosis could potentially curb HIV transmission at population level among MSM, along with other strategies. Future assessment of HIV prevention and control policy can be carried out using routinely collected longitudinal data from health information systems.

Using data from the 2015 China Household Finance Survey, we find that secure land tenure reduces informal land rentals between acquaintances. Additionally, secure land tenure increases land rent ev...

Although the literature finds that renting out farmland can increase farmer’s income, whether lessors’ subjective well-being (SWB) increases or not has been under-analysed. We use data from the 201...

PurposeThis study investigates the effect of renting in land on farm productivity, and the impacts of rented-in land size and transaction partner type on farm productivity.Design/methodology/approachData from the 2015 China Household Finance Survey are analyzed using an extended regression model and the two-stage least squares method.FindingsFarm households that rent in land are likely to achieve higher farm productivity, and ignoring endogeneity underestimates the positive effect of land renting-in. Further evidence indicates that rented-in land size has an insignificant impact on farm productivity, and that there is no difference in farm productivity between lessees renting-in land from acquaintances and those renting-in land from non-acquaintances. These results may be caused by the higher degree of marketization of land rentals between acquaintances in China. With increasing competition in agricultural factor markets, in theory, rented-in land size should not affect farm productivity.Practical implicationsOverall, the analysis suggests that renting in land improves farm productivity, which supports the land transfer policies that have been rolled out in recent decades in China. However, our finding that rented land size does not affect farm productivity, consistent with the results in the literature, implies that the Chinese government should no longer subsidize or prefer large farms with low productivity. More attention should be paid to small lessees and market-oriented land rentals between acquaintances. Promoting the marketization of land transfers inside acquaintance networks could realize the potential of the land market, especially if land transfers decrease.Originality/valueThis study identifies the effects of renting in land, rented-in land size and type of rental transaction partner on farm productivity using nationally representative data. The findings imply that the government should pay more attention to the marketization of land rentals between acquaintances. Although existing studies regard land rental between acquaintances as informal and of low efficiency, the recent evidence shows that China's land markets are changing, and policy makers should adjust their policies accordingly.

This paper theoretically and empirically investigates whether acquaintance networks influence the deviation of land rent from the reference point advanced by Hart and Moore. The coefficient of variance and the range of land rent are used to represent the degree of deviation from the reference point. Based on village‐level data from the 2015 China Household Finance Survey, the estimated results indicate that land rent between acquaintances is more likely to significantly deviate from the reference point. Although rental transactions are conducted between acquaintances, larger deviations from the reference are also associated with a longer time to close deals. Our analysis using household‐level data further supports our findings, indicating that land rental markets embedded in the acquaintance networks of rural China are in a transition period and have characteristics of both relational and market orientation. The policy makers should introduce more outer village lessees or other market ingredients to increase the voluntary marketization of land rentals inside acquaintance networks.

Over the last decade, introducing outer village lessees has been an important approach to increasing the marketization of land rentals in rural China. However, with large numbers of informal featur...

This study examines the effects of the geographical distance between adult offspring and their elderly parents on their support provided to their parents in rural China. Monetary and non-monetary support is closely related to the physical and psychological well-being of the elderly. Three waves of the China Health and Retirement Longitudinal Study (CHARLS) are used to identify a causal effect of the location of the adult offspring on outcomes such as financial transfers to the parents and provision of emotion/physical support. We find that the effects vary with the type of support. The effect of geographical distance on financial support sent by adult children to elderly parents shows a semi-inverted ‘U-shaped’ trend that first increases and then slowly decreases. The frequency of visit by the adult child to elderly parents decreases significantly as distance increase. Further analysis examines the heterogeneity of these effects. The paper combines theoretical and empirical evidence to illustrate how adult children make use of their limited time and money to provide parental support when they migrate different distances from home. Accepted version

Objective: The objective of this study was to understand the molecular transmission characteristics of newly reported HIV infections in the city of Pengzhou, Sichuan Province, to analyze the risk factors of transmission network and spatial clustering and the transmission characteristics, and to provide a scientific basis for precision prevention and intervention. Methods: Anticoagulated whole blood was collected from newly reported HIV infections in Pengzhou from March 2019 to August 2021. After the plasma was isolated, the HIV-1 pol gene was amplified and sequenced by reverse transcriptase polymerase chain reaction (PCR). The obtained gene sequences were used to construct a maximum likelihood phylogenetic tree for the analysis of virus subtypes, and a molecular transmission network was constructed using the genetic distance method to evaluate the transmission pattern of people living with HIV/AIDS in Pengzhou. A logistic regression model was used to find out the potential risk factors for entering the molecular transmission network with the number of nodes ≥ 2. Spatial analysis is used to show the geographical pattern of the proportion of newly reported HIV infections entering the molecular transmission network, and a flow map is used to show the intensity of transmission within and between townships. Results: A total of 463 newly reported HIV-infection sequences were obtained in this study, including 237 cases (51.19%) of CRF01_ AE, 159 cases (34.34%) of CRF07_BC, 45 cases (9.72%) of B, 15 cases (3.24%) of CRF08_BC and 7 cases (1.5%) of others. The number of clusters was the highest when the gene distance was 0.009, with a total of 246 sequences entering the network, forming 54 clusters, and the network entry rate was 55.36%. There were 170 sequences with more than two nodes in the network sequence. The logistic regression showed that compared with age < 50 years old, age ≥ 50 years old has a higher risk of transmission (OR = 3.43, 95% CI = 2.06–5.71); compared with farmers, the risk of transmission within industry is lower (OR = 0.046, 95% CI = 0.25–0.87); and compared with CRF07_BC, CRF01_AE (OR = 6.09, 95% CI = 3.60–10.30) and B (OR = 20.31, 95% CI = 8.94–46.13) had a higher risk of transmission. Men aged ≥ 50 years are mainly clustered with women between 50 and 70 years of age. In addition to being clustered with gay men, there are nine (50%) and three (16.7%) chains of transmission between gay men and heterosexual men and women, respectively. In the geographical space, there is no hot spot clustering of the molecular propagation network. The subtype B was mainly distributed in the town of Tianpeng and formed transmission networks in eastern Pengzhou;0020CRF01_AE is mainly distributed in the town of Lichun and formed transmission networks in the west and north of Pengzhou. Conclusion: This study reveals the characteristics and influencing factors of molecular network transmission in the region, as well as the spatial transmission characteristics of newly reported HIV infections in recent years, and reveals the geographical differences in HIV-1 transmission. The results provide a scientific basis for the development of local AIDS-specific intervention measures.

PurposeThe purpose of this paper is to assess the links between basic farmland preservation and land transfers in rural China.Design/methodology/approachThe Chinese provincial panel data from 2006 to 2016 were analyzed with the use of Arellano–Bond linear dynamic panel data estimations.FindingsThe basic farmland preservation policy negatively affects the land transfer rate. In addition, this policy is most likely to limit land transfers between local acquaintances in the major grain-producing areas. Further evidence indicates that the basic farmland preservation policy has a negative impact on land rentals in general. Considering that land transfers such as exchanges and take-overs are excluded from rental transactions between acquaintances, the policy’s constraints on land use are likely to hinder land rentals between acquaintances, which are market-oriented.Practical implicationsOverall, this study’s analysis suggests that the farmland preservation policy’s constraints on land use rights are likely to result in a major diminishment of the rural rental markets. Under this policy, land that is designated as basic farmland cannot be converted to another use. However, it remains possible to improve the productivity of agriculture through other means. These possible avenues for improvement include enhancing the efficiency of production through expanding the scale of farming operations and developing the social services aspect of agriculture (i.e. the basic farmland preservation policy is likely to realize more social revenue than can be gained from land transfers). Thus, the arrangement of the basic farmland preservation policy in China can be managed in a way that is both economical and reasonable.Originality/valueTo ensure food security, China has enacted several laws and regulations to preserve basic farmland, and it has promoted land transfers to improve farm productivity. Therefore, it is important to understand whether the basic farmland preservation policy restricts land use rights and hinders land transfers that could improve productivity. This study provides empirical evidence showing that the basic farmland preservation policy is actually not conducive to promoting land transfers and that it even discourages the market orientation of land rentals between acquaintances. In dealing with this issue, the Chinese Government should seek to balance the relationship between preserving basic farmland and promoting land transfers.

Based on provincial panel data of China ranging from 2004 to 2015, this paper has empirically examined the effect of basic public service on the urban–rural income inequality with a system generalised method of moments (sys-GMM). We arrive at the following conclusions: 1) the improvement of public service provision is conducive to narrowing the urban–rural income gap; 2) compared with the ‘hard’ public services (including infrastructure, environmental protection and cultural facilities), the ‘soft’ public services (including education, medical care and social security) play a more significant role in reducing the disparity; 3) the household registration system impairs the welfare brought by the ‘soft’ public services and exacerbates the passive effect of ‘hard’ public services on the income gap; 4) the interactive impact of household registration regulation and public service provision on the income gap is more significant in developed areas. These findings suggest the government should give priority to the improvement of ‘soft’ public services, reevaluate the way of spending on ‘hard’ public services in rural areas and deepen the household registration system reform.

Developing agricultural mechanization services (AMS) is commonly regarded as an important step in the modernization of smallholder farmers in China. However, given the increase in the opportunity costs of agriculture and the high cost of AMS, further study is needed to determine the relationship between AMS and smallholder farmers' exit from agricultural production. In this paper, data from the China Family Panel Survey collected in 2017 and 2019 are used to investigate this issue. Our findings show that the development of AMS reduces the probability that smallholder farmers exit from agricultural production though land abandonment, but increases the probability through land renting-out. Further analysis shows that with the emergence of large farm operators and the increase in land size rented by large farm operators, the development of AMS induces smallholder farmers' exit from agricultural production through both land abandonment and land renting-out. We also find that AMS can increase the market demand for land transfers and the marketization of land rentals, and as land markets develop, AMS induce smallholder farmers' exit through the abandonment of fragmented and distant land plots.

BACKGROUND HIV disproportionately affects men who have sex with men (MSM) in China. The HIV epidemic is largely driven by unprotected anal sex (ie, sex not protected by condoms or HIV pre-exposure prophylaxis [PrEP]). The possible association between unprotected anal sex and the use of geospatial networking apps has been the subject of scientific debate. OBJECTIVE This study assessed whether users of a gay geospatial networking app in China were more likely to use condoms when they met their partners online versus offline. A case-crossover analysis, with each person serving as his own control, was employed to address the potential bias that men looking for sex partners through an online dating medium might have inherently different (and riskier) patterns of sexual behavior than men who do not use online dating media. METHODS A cross-sectional survey was administered in 2018 to adult male users of Blued—a gay geospatial networking app—in Beijing, Tianjin, Sichuan, and Yunnan, China. A case-crossover analysis was conducted among 1311 MSM not taking PrEP who reported engaging in both unprotected and protected anal sex in the previous 6 months. Multivariable conditional logistic regression was used to quantify the association between where the partnership was initiated (offline or online) and the act of unprotected anal sex, controlling for other interval-level covariates. Four sensitivity analyses were conducted to assess other potential sources of bias. RESULTS We identified 1311 matched instances where a person reported having both an unprotected anal sex act and a protected anal sex act in the previous 6 months. Of the most recent unprotected anal sex acts, 22.3% (292/1311), were initiated offline. Of the most recent protected anal sex acts, 16.3% (214/1311), were initiated offline. In multivariable analyses, initiating a partnership offline was positively associated with unprotected anal sex (odds ratio 2.66, 95% CI 1.84 to 3.85, P CONCLUSIONS Among Blued users in 4 Chinese cities, men were less likely to have unprotected anal sex in partnerships that they initiated online compared with those that they initiated offline. The relationship was strong, with over 2.5 times the likelihood of engaging in unprotected anal sex in partnerships initiated offline compared with those initiated online. These findings suggest that geospatial networking apps are a proxy for, and not a cause of, high-risk behaviors for HIV infection; these platforms should be viewed as a useful venue to identify individuals at risk for HIV transmission to allow for targeted service provision.

As a core industry of the national economy, there is no doubt that the agricultural sector has to adapt to the new economic development. In the literature, many researchers have agreed that agricultural export is an important factor affecting economic growth. This paper explores the contribution of chicken products&rsquo, export to economic growth and the causal relationship between them. Based on the data from the Food and Agriculture Organization of the United Nations (FAO) and World Bank between 1980 and 2016, this paper describes and compares the characteristics of chicken products&rsquo, export trade of China, the United States, and Brazil. By applying the co-integration analysis, we find that there is no significant long-term equilibrium relationship between chicken products&rsquo, export and economic growth rate in China, the United States, or Brazil. However, the growth rate of chicken products&rsquo, export significantly promotes the economic growth rate for the United States. Besides, for both China and the United States, the direct pull degree (an estimator quantifying the degree of agricultural products&rsquo, exports in stimulating economic growth) of chicken products&rsquo, export is relatively small and less volatile. Yet, the direct pull degree of China is 14 times that of the United States, and the contribution to the economic growth rate of the United States is 8 times that of China. Both the direct pull degree and economic growth contribution of chicken products&rsquo, export of Brazil fluctuates more often, and its direct pull degree is 0.25 times that of China, and the economic contributions to the growth rate is 1.65 times that of China.

Personalized medicine has received increasing attentions among scientific communities in recent years. Because patients often have heterogenous responses to treatments, discovering individualized treatment rules (ITR) is an important component of precision medicine. To that end, one needs to develop a proper decision rule using patient-specific characteristics to maximize the expected clinical outcome, i.e. the optimal ITR. Recently, outcome weighted learning (OWL) has been proposed to estimate optimal ITR under a weighted classification framework. Since most of commonly used loss functions are unbounded, the resulting ITR may suffer similar effects of outliers as the corresponding classifiers. In this paper, we propose robust OWL (ROWL) to build more stable ITRs using a new family of bounded and non-convex loss functions. Moreover, we extend the proposed ROWL method to the multiple treatment setting under the angle-based classification structure. Our theoretical results show that ROWL is Fisher consistent, and can provide the estimation of rewards’ ratios for the resulting ITRs. We develop an efficient difference of convex functions algorithm (DCA) to solve the corresponding nonconvex optimization problem. Through analysis of simulated examples and a real medical dataset, we demonstrate that the proposed ROWL method yields more competitive performance in terms of the empirical value function and the misclassification error than several existing methods.

Background HIV disproportionately affects men who have sex with men (MSM) in China. The HIV epidemic is largely driven by unprotected anal sex (ie, sex not protected by condoms or HIV pre-exposure prophylaxis [PrEP]). The possible association between unprotected anal sex and the use of geospatial networking apps has been the subject of scientific debate. Objective This study assessed whether users of a gay geospatial networking app in China were more likely to use condoms when they met their partners online versus offline. A case-crossover analysis, with each person serving as his own control, was employed to address the potential bias that men looking for sex partners through an online dating medium might have inherently different (and riskier) patterns of sexual behavior than men who do not use online dating media. Methods A cross-sectional survey was administered in 2018 to adult male users of Blued—a gay geospatial networking app—in Beijing, Tianjin, Sichuan, and Yunnan, China. A case-crossover analysis was conducted among 1311 MSM not taking PrEP who reported engaging in both unprotected and protected anal sex in the previous 6 months. Multivariable conditional logistic regression was used to quantify the association between where the partnership was initiated (offline or online) and the act of unprotected anal sex, controlling for other interval-level covariates. Four sensitivity analyses were conducted to assess other potential sources of bias. Results We identified 1311 matched instances where a person reported having both an unprotected anal sex act and a protected anal sex act in the previous 6 months. Of the most recent unprotected anal sex acts, 22.3% (292/1311), were initiated offline. Of the most recent protected anal sex acts, 16.3% (214/1311), were initiated offline. In multivariable analyses, initiating a partnership offline was positively associated with unprotected anal sex (odds ratio 2.66, 95% CI 1.84 to 3.85, P Conclusions Among Blued users in 4 Chinese cities, men were less likely to have unprotected anal sex in partnerships that they initiated online compared with those that they initiated offline. The relationship was strong, with over 2.5 times the likelihood of engaging in unprotected anal sex in partnerships initiated offline compared with those initiated online. These findings suggest that geospatial networking apps are a proxy for, and not a cause of, high-risk behaviors for HIV infection; these platforms should be viewed as a useful venue to identify individuals at risk for HIV transmission to allow for targeted service provision.

There exist problems of land abandonment and low-efficiency land use when China is undergoing active rural-urban migration. Whether increasing land scale can attract more labor engaged in land use is important to increase land-use efficiency and relieve labor shortage in agriculture. This paper uses data from the 2015 China Household Finance Survey to assess the relationship between land renting-in and labor input in agriculture. The results show that land renting-in increases labor input in agriculture. With higher land rents and profit motives, more labor in lessees’ households will be engaged in agriculture. Further analysis indicates that there is no difference in labor input in agriculture between lessees transacting with acquaintances and those transacting with non-acquaintances for the increasing marketization of land rentals between acquaintances in today’s China. Our analysis implies that developing land rental markets and promoting the marketization of land rentals are important approaches to land use sustainability and relieving labor shortage in agriculture, which has great policy implications for countries with rapid rural-urban migration and abandoned arable land.

China’s grain security is an increasing global concern. Most researchers argue that land renting-in leads to the cultivation of non-grain products in rural China. We use household-level data collected in China to assess the relationship between land renting-in and grain production. Our results indicate that land renting-in positively affects rice acreage, especially when there is less labor available for agriculture. The channel of the effect is that lessees tend to increase the use of machinery in rice production, but not in the production of cash crops because the production of grain crops can be more easily mechanized in rural China. The Chinese government should still pay close attention to the cultivation of non-grain products caused by land renting-in because workers in the production of cash crops may also be easily replaced by new agricultural technologies.

Childhood obesity in China has been increasingly cited as a major public health issue in recent decades. Although grandparents are more likely than other guardians to spoil grandchildren by feeding them more food and limiting their physical activity, the effect of grandparents on grandchildren’s weight outcome is under-analyzed. Using data from the China Health and Nutrition Survey, we examine the effect of grandparents’ coresidence on childhood weight outcome with a sample of 2- to 13-year-old children in China. We use instrumental variables to address the potential endogeneity of grandparents’ coresidence. After controlling for a rich set of covariates and unobserved individual heterogeneity, we show that the effect of grandparents’ coresidence on childhood weight outcome is significantly positive. Grandparents’ coresidence affects a grandchild’s weight outcome through changes in dietary patterns and physical activity. The effects on dietary patterns exist in urban areas and significantly lower in rural areas. Grandparents’ coresidence decreases physical activity more in rural areas than in urban areas. Furthermore, the effects of coresidence on protein intake and physical activities of children above 6 are significantly higher for males than females. A robustness check, including an ordered logit model with a body mass index category and estimation with additional data, validates our findings.

Land fragmentation is regarded as obstacle to agricultural productivity and remains serious in rural China. Many researchers suggest that developing land rental markets is one effective approach to land defragmentation, but few papers empirically confirm it. This paper employs Chinese provincial panel data from 2006 to 2016 to assess the relationship between land rental and fragmentation. The estimated results indicate that the number of land plots per farm household does not decline with land transfer rate increasing when considering the problem of endogeneity. And the farm households are likely to consolidate fragmented land through land rental markets when the probability to plant cash crops or expected income from land rental is high. Thus, land rental markets with informality and rigid land use control in rural China are unlikely to result in an effective defragmentation.

Capacity constraints have major effects on restaurant competition. This article captures the impact of capacity constraints on quality and quantity competition of restaurant industry by employing a two-stage asymmetric capacity constraints model. There are several findings from this study. First, results of this study indicate that reputation difference increases total outputs and quality in equilibrium. Second, capacity constraints decrease the consumer surplus (CS) as well as social welfare (SW), but restaurants benefit from capacity constraints sometimes. Third, capacity reduces both the quality and quantity of the competitor. Furthermore, restaurants raise their prices if consumers are quality-sensitive or lower the quality if consumers are price-sensitive under capacity constraints. Fourth, this study compares the total quality, CS, and SW under four cases: no restaurant faces constraints, small restaurant faces constraints, big restaurant faces constraints, and both small and big restaurants face constraints. The total quality investment, CS, and SW are highest if a small restaurant faces capacity constraints while the larger one does not.

Traditionally, rental transactions between acquaintances have been regarded as informal, and associated with low rents. This view implies market segmentation and the malfunctioning of prices. Our study uses household-level data from the China Household Finance Survey (CHFS) in 2015 to assess the relationship between transaction partners and land rents, with consideration of the mediating effect of profit motivations. The results indicate that among villagers who lease land for profit, there is no average difference in land rents between transactions conducted between acquaintances and those conducted between strangers. We also find that profit motivation positively affects land rents. If lessees rent land for the sake of profit, higher land rents are paid no matter who they transact with. Lower land rents are more likely to apply in transactions between acquaintances or transactions conducted for non-profit motivation. Furthermore, we find that more than 52.5% of rental transactions between acquaintances in rural China are done for the sake of profit. Our analysis implies that a large number of formal land rental transactions take place within acquaintance networks, and that land rents in rural markets are converging.

China’s food security has increasingly been one worldwide concern. And, most researchers argue that land transfer further aggravates the problem of non-grain in rural China. We theoretically pursue the the internal mechanism of the effects of land rental on the grain production and then employ 2,088 household survey data collected in China to assess their relationship. The estimated results indicate that land rental positively affects grain production, especially with the decrease of agricultural labor. Contrarily, land rental has significantly negative impact on grain production with the increase of agricultural labor. Besides, we also find that the reason that land rental stimulates grain production is that the grain production can be more easily mechanized than that of cash crops in rural China, which is conductive to reducing the high labor cost in agriculture and encouraging off-farm employment. Thus, when considering the development of mechanization in grain production and high labor cost in agriculture, grain production has been the voluntary choice of the land leaseholders, and this undoubtedly ensures China’s grain security.

We obtain explicit expressions for the elements of the Fisher information matrix (FIM) for a single pair of order statistic and its concomitant, and Type II right, left, and doubly censored samples from the Marshall-Olkin bivariate exponential distribution. We also obtain the limiting form of the FIM for the censored samples. We evaluate the FIM for selected parameter values and sample size of 10, and determine simple, close approximations based on the limiting form. We discuss implications of our findings to inference based on small and large samples and for ranked-set samples from this distribution.

In this paper we evaluate the relative importance of the two main channels, namely the composition effect and the income structure effect, through which the paternal income affects children's income inequality. Using data on 2677 pairs of father and children from China Health and Nutrition Survey (CHNS), we construct the counterfactual income of children from poor families if they had the same characteristics as children from rich families. We propose an instrumental variable quantile regression-based method to solve the endogeneity problem and decompose the rich dad effect on income inequality into the composition effect and the income structure effect. We find that the composition effect explains at least 80% of the income difference at any quantile, and it explains all the income difference at the top four deciles. Income structure effect has a significant impact only at quantiles between 20% and 40%, where it explains about 20% of the income difference.

Childhood obesity in China has been increasingly cited as a major public health issue in recent decades. The effect of grandparents on grandchildren's weight outcome is under-analyzed. Using data from the China Health and Nutrition Survey, we examine the effect of grandparents' coresidence on childhood weight outcome with a sample of 2-13-year-old children in China. We use instrumental variables to address the potential endogeneity of grandparents' coresidence. We show that the effect of grandparents' coresidence on childhood weight outcome is significantly positive. Grandparents' coresidence affects a grandchild's weight outcome through changes in dietary patterns and physical activity. The effects on dietary patterns exist in urban areas and significantly lower in rural areas. Grandparents' coresidence decreases physical activity more in rural areas than in urban areas. Furthermore, the effects of coresidence on protein intake and physical activities of children above 6 are significantly higher for males than females. A robustness check, including an ordered logit model with a body mass index category and estimation with additional data, validates our findings.

Recently, continuing outbreaks of avian influenza in China have not only caused great loss to the agricultural sector but also brought fear and distrust to consumers, seriously undermining consumer confidence in chicken products. We investigated consumers&rsquo, purchase intentions during avian influenza outbreaks by examining a regionally representative sample of 330 consumers in Guangzhou. With respect to 7 kinds of attributes, the ordered logit analysis indicated that possible health threat and uncertainty of the origin of poultry products may cause concern among consumers and cause them to avoid purchasing chicken products. Media reports have a great influence on consumers&rsquo, intentions to purchase chicken products during avian influenza outbreaks. Overall, this study suggests establishing an effective mechanism of public knowledge (of chicken products&rsquo, safety and quality) enhancement, in order to curb misleading media reports during avian influenza outbreaks.

Let $$(X_{i:n},Y_{[i:n]})$$ be the vector of the $$i$$ th $$X$$ -order statistic and its concomitant observed in a random sample of size $$n$$ where the marginal distribution of $$X$$ is absolutely continuous. We describe some general algorithms for simulation of complete and Type II censored samples $$\{(X_{i:n}, Y_{[i:n]}), 1 \le i \le r \le n\}$$ from such bivariate distributions. We study in detail several algorithms for simulating complete and censored samples from Downton, Marshall---Olkin, Gumbel (Type I) and Farlie-Gumbel-Morgenstern bivariate exponential distributions. We show that the conditioning method in conjunction with an efficient simulation of exponential order statistics that exploits the independence of spacings provides the best method with substantial savings over the basic method. Efficient simulation is essential for investigating the finite-sample distributional properties of functions of order statistics and their concomitants.