There are encouraging advances in prosthetic vision for the blind, including retinal and cortical implants, and other ?sensory substitution devices? that use tactile or electrical stimulation. However, they all have low resolution, limited visual field, and can display only few gray levels...

Background: Vitamin D deficiency during pregnancy has been associated with increased risk of complications and adverse perinatal outcomes. We evaluated seasonal variation of 25-hydroxyvitamin D [25(OH)D] among pregnant women, focusing on patterns and determinants of variation. Methods: Data came...

In the latter years of Barack Obama?s presidency, the effort to mobilize public opinion and grassroots activism on climate change has led to a broader shift in environmental politics, as environmental organizations and their allies devote ever greater resources to shaping the outcome of...

Based on models with calibrated parameters for infection, case fatality rates, and vaccine efficacy, basic childhood vaccinations have been estimated to be highly cost effective. We estimate the association of vaccination with mortality directly from survey data. Using 149 cross-sectional...

We present a new model of investors delegating portfolio management to professionals based on trust. Trust in the manager reduces an investor?s perception of the riskiness of a given investment, and allows managers to charge fees. Money managers compete for investor funds by setting fees, but...

Last year was difficult for Google Flu Trends (GFT). In early 2013, Nature reported that GFT was estimating more than double the percentage of doctor visits for influenza like illness than the Centers for Disease Control and Prevention s (CDC) sentinel reports during the 2012 2013 flu season...