The Long-Run Economic Consequences of Iodine Supplementation

We present evidence on the impacts of a large-scale iodine supplementation program in Tanzania on individuals' long-term economic outcomes. Exploiting the timing and location of the intervention, we document that in utero exposure to the program increased completed years of education and income scores in adulthood. We find no increase in total employment, but a significant change in the occupational structure. Cohorts exposed to the program are less likely to work in agricultural self-employment and more likely to hold skilled jobs that typically demand higher levels of education. Together, these results demonstrate that iodine deficiency can have long-run implications for occupational choices and labor market incomes in low-income regions.

Factors affecting intracellular calcium influx in response to calcium ionophore A23187 in equine sperm

BACKGROUND

Exposure to the calcium ionophore A23187 may present a "universal" sperm treatment for IVF, as it bypasses capacitation pathways. However, success in utilizing A23187 is variable, especially in equine spermatozoa. Notably, albumin is used during A23187 treatment but paradoxically is thought to suppress A23187 action. Essentially no critical data are available on the effects of A23187 and albumin concentrations, ratios, or addition protocols on changes in intracellular calcium ([Ca]_i ) in any cell type.

OBJECTIVE

To determine factors that affect the action of A23187 on [Ca]_i in equine and murine spermatozoa.

METHODS

Spermatozoa were loaded with Fluo-4 and changes in fluorescence after A23187 treatment were measured under various conditions using a microplate reader.

RESULTS

Concentrations of bovine serum albumin (BSA) and A23187, type of BSA, makeup of A23187 stock solutions (i.e., 1° stock (DMSO) or 2° stock made with medium, water or DMSO), order of addition of spermatozoa and A23187, incubation of media before sperm addition, species of spermatozoa, and time of addition of BSA all affected [Ca]_i in response to A23187 treatment. In equine spermatozoa already exposed to 10 µM A23187, addition of BSA to 33 mg/ml to "quench" the A23187 did not affect [Ca]_i . When this concentration of BSA was added to spermatozoa exposed to 1 µM A23187, [Ca]_i in murine spermatozoa returned to baseline, however, equine spermatozoa continued to exhibit increased [Ca]_i . Addition of BSA to 33 mg/ml to media containing 1 µM A23187, prior to addition of spermatozoa, completely inhibited change in [Ca]_i in both murine and equine spermatozoa.

CONCLUSION

These results represent some of the first critical data on the effects of albumin and other procedural factors on A23187-induced changes in [Ca]_i in any cell type. Our findings help to explain the variability in reported response of spermatozoa to A23187 among species and among laboratories.

Avoidable environmental disasters and infant health: Evidence from a mining dam collapse in Brazil

We study the health consequences of one of the largest environmental disasters of the world mining industry, which largely stemmed from regulatory failure. Exploiting the timing and location of the Mariana mine tailings dam collapse in Brazil, we show that in utero exposure to the tragedy significantly reduced birth weight and increased infant mortality. The adverse effects were stronger for infants born to less educated and nonmarried mothers. These findings indicate that poorly enforced environmental regulation may have long-term welfare impacts on local communities.