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Background: In China, there is a dearth of data on the iodine balance study for adults. Especially, due to the special physiological cycle, the research of female iodine balance is insufficient or lasts for a short time. In the present study, we spent more than two months to explore the basal iodine requirement based on healthy Chinese female adults and a new ‘iodine overflow’ theory was proposed for the study of iodine balance. Methods: A total of 36 Chinese healthy female adults (age 20.67 ± 1.10 years) were recruited for this study, which included 40 days low iodine depletion period and 6 stages of 30 days supplementation study. Uniform diets with different iodine content were provided, in which non-iodized salt and pure water were provided in all the meals and the content of iodine in the diet was regulated by accurately weighing dairy products with measured iodine content. The total iodine intake from food was collected using weighing and duplicate portion method and the total iodine excretion through 24-hour urine and staged faeces were completely gathered and monitored. The iodine content in diet, urine and feces were measured by ICP-MS. The iodine intake and excretion were calculated and a mixed effects models model was set up between incremental iodine intake and incremental iodine excretion based on the ‘iodine overflow’ theory. Findings: At the start of experiment, the 24h UIC was 233.31±122.47μg/L, which meant an iodine overnutrition for the majority of subjects. The iodine intake and excretion were 13.64μg/day and 48.58μg/day at the end of 1st stage. The incremental iodine intakes (Δ iodine intake) was 21.05, 39.64, 60.85, 88.16, 120.25μg/day and the incremental iodine excretion (Δ iodine excretion) was 25.75, 37.03, 54.67, 77.59, 105.43μg/day for the supplementation stages. According to the ‘iodine overflow’ hypothesis, the zero iodine balance (Δ iodine intake = Δ iodine excretion) derived from a mixed effect model indicated a mean iodine intake of 52.24μg/d(1.00μg/d•kg). The RNI for iodine to healthy Chinese female adult was 73.1μg/d(1.39μg/d•kg). Interpretation: Our findings indicate that basal iodine requirement may be much less than the current iodine intake recommendation. A daily iodine intake of 52.24μg/d may meet the basal iodine requirement for healthy Chinese female and Chinese women may need more than 20% iodine intake than men based on the ‘iodine overflow’ hypothesis. The ‘iodine overflow’ theory could provide a new idea for iodine balance research and the further studies should be needed for the iodine intake recommendation. Trial Registration: The trial was registered at the Chinese Clinical Trial Registry (No:ChiCTR1800016184). Funding: National Natural Science Foundation of China and Sanming Project of Medicine in Shenzhen. Declaration of Interest: The authors declare that they have no conflict of interest. Ethical Approval: This study was approved by the Ethical Committee of the National Institute for Nutrition and Health, Chinese Center for Disease Control and Prevention.

Major cities in China and many other fast-growing economies are expanding their subway systems in order to address worsening air pollution and traffic congestion. This paper quantifies the impact of subway expansion on air quality by leveraging fine-scale air quality data and the rapid build-out of 14 new subway lines and 252 stations in Beijing from 2008 to 2016. Our main empirical framework examines how the density of the subway network affects air quality across different locations in the city during this period. To address the potential endogenous location of subway stations, we construct an instrument based on historical subway planning, long before air pollution and traffic congestion were of concern. Our analysis shows that an increase in subway density by one standard deviation improves air quality by two percent and the result is robust to a variety of alternative specifications including the distance-based difference-in-differences method. The total discounted health benefit during a 20-year period from reduced mortality and morbidity as a result of 14 new subway lines amounts to $1.0-3.1 billion, or 1.4-4.4 percent of the total construction and operating cost.

Group lending has been widely adopted in the past thirty years by many microfinance institutions as a means to mitigate information asymmetries when delivering credit to the poor. This paper proposes an empirical method to address the potential omitted variable problem resulting from unobserved group types when modeling the repayment behavior of group members. We estimate the model using a rich dataset from a group lending program in India. The estimation results support our model specification and show the advantages of relying on a type-varying method when analyzing the probability of default of group members.

This paper extends Ghatak (1999)'s base model of group lending with asymmetric information by allowing individuals to differ both in their exogenous risk type and in their endogenous effort level. We find that joint liability leads to positive assortative matching in both a non-cooperative and a cooperative game setting. Groups of safe borrowers also exhibit higher effort levels, which further reinforces their likelihood of repayment as opposed to risky groups.

We present evidence that farmers adjust agricultural inputs in response to within-season temperature variation, undertaking defensive investments to reduce the adverse agroecological impacts of warmer temperatures. Using panel data from Kenyan maize growing households, we find that higher temperatures early in the growing season increase the use of pesticides, while reducing fertilizer use. Warmer temperatures throughout the season increase household weeding effort. These adjustments arise because greater heat increases the incidence of pests, crop diseases and weeds, compelling farmers to divert investment from productivity-enhancing technologies like fertilizer to adaptive, loss-reducing, defensive inputs like pesticides and weeding labor.

This study investigates the consequences of poor implementation in public workfare programs, focusing on the Mahatma Gandhi National Rural Employment Guarantee Act (MGNREGA) in India. Using nationally representative data, we test empirically for a discouraged worker effect arising from either of two mechanisms: administrative rationing of jobs among those who seek work and delays in wage payments. We find strong evidence at the household and district levels that administrative rationing discourages subsequent demand for work. Delayed wage payments seem to matter significantly during rainfall shocks. We find further that rationing is strongly associated with indicators of implementation ability such as staff capacity. Politics appears to play only a limited role. The findings suggest that assessments of the relevance of public programs over their lifecycle need to factor in implementation quality.

Rapid population growth in many developing countries has raised concerns regarding food security and household welfare. To understand the consequences of population growth in a general equilibrium setting, we examine the dynamics of population density and its impacts on household outcomes using panel data from Indonesia, combined with district-level demographic data. Historically, Indonesia has adapted to land constraints through a mix of agricultural intensification, expansion of the land frontier, and non-farm diversification, with public policies playing a role in catalyzing all of these responses. In contemporary Indonesia we find that human capital determines the effect of increased population density on per capita household consumption expenditure. The effect of population density is positive if the average educational attainment is high (above junior high school), while it is negative otherwise. On the other hand, farmers with larger holdings maintain their advantage in farming regardless of population density. The paper concludes with some potential lessons for African countries from Indonesia’s more successful rural development experiences.

Farmers in developing countries face relatively large income risk and have limited access to formal financial products that can help them manage their risk. We present results from a randomized controlled trial in rural China designed to understand whether a small change in the timing of a premium payment for a swine insurance contract helps to overcome an important barrier to insurance demand and, if so, whether the resulting increase in insurance would allow farmers to increase investment in activities that expose them to the risk being insured against. We find that insurance take-up is three times higher among those who were given the option to pay at the end of the insured period. We use the random variation in insurance take-up thus induced to estimate the impact of insurance on investment. We find a positive impact on investment, which suggests that without insurance, farmers were not able to fully insure; that the new payment plan helped farmers to overcome an important barrier to insurance purchases; and that encouraging insurance purchases in this way can have a positive long-term effect on the income and welfare of rural households in China.

India’s Mahatma Gandhi National Rural Employment Guarantee Scheme (MGNREGS) is the largest public works employment project in the world. Its most direct poverty reduction pathway is through boosting employment and income for the poor. How effectively this direct transfer mechanism reduces poverty turns fundamentally on the degree to which MGNREGS targets its resources toward otherwise-poor households. To explore this question, we use the 2009/10 National Sample Survey data to describe patterns of seeking, rationing, and participation in MGNREGS. At the national level, we find that the self-targeting design of MGNREGS leads to greater rates of self-selection into the program by poorer and scheduled tribe or scheduled caste households. However, the administrative rationing of MGNREGS jobs is not pro-poor but, rather, exhibits a sort of middle-class bias. At the state level, roughly half of 27 states exhibit rationing and participation profiles that signal effective pro-poor targeting. The other half of India’s states struggle to avoid high rates and regressive patterns of administrative rationing of MGNREGS jobs to which the poor have a legal right. Our results suggest that MGNREGS can be effectively deployed to attract, employ and improve the well-being of poor rural households but there remains room for improvement and perhaps much to be learned from in-depth comparative analysis of MGNREGS program implementation across states.

This paper examines the unexplored link between the prevalence of overweight and obesity and vehicle demand in the United States. Exploring annual sales data of new passenger vehicles at the model level in 48 U.S. counties from 1999 to 2005, we find that new vehicles demanded by consumers are less fuel-efficient on average as a larger share of people becomes overweight or obese. The OLS results show that a 10 percentage point increase in obesity and overweight reduces the average MPG of new vehicles demanded by 1.4 percent, an effect requiring a 12 cent increase in gasoline prices to counteract. The 2SLS results after controlling for possible endogeneity in overweight and obesity prevalence put those two numbers at 5 percent and 54 cents, respectively. These findings, robust to a variety of specifications, suggest that policies to reduce overweight and obesity can have additional benefits for energy security and the environment.

We quantify the importance of endogenous peer effects in group lending programs by estimating a static game of incomplete information. Endogenous peer effects describe how one's behavior is affected by the behavior of her peers. Using a rich data set from a group lending program in India, our empirical analysis presents a robust finding of large peer effects. The benchmark model suggests that the probability of a member making a full repayment would be 11 percentage points higher if all the fellow members were to make full repayment compared with a scenario in which none of the other members repay in full. We find that peer effects would be overestimated without controlling for unobserved group heterogeneity and that inconsistencies exist in the estimated effects of other variables without modeling peer effects and unobserved heterogeneity.