This paper examines the central hypothesis of the influential Malthusian theory, according to which improvements in the technological environment during the pre-industrial era had generated only temporary gains in income per capita, eventually leading to a larger, but not significantly richer, population. Exploiting exogenous sources of cross-country variations in land productivity and the leve...

We study the effect of a prolonged epoch of reionization on the angular power spectrum of the Cosmic Microwave Background. Typically reionization studies assume a sudden phase transition, with the intergalactic gas moving from a fully neutral to a fully ionized state at a fixed redshift. Such models are at odds, however, with detailed investigations of reionization, which favor a more extended ...

Look around. No “good old-fashioned war” is in sight. There are a few possibilities—for example, on the Korean peninsula; or between China and Taiwan; or India and Pakistan; and, as usual, in the Middle East—but these do not seem imminent. Moreover, the most recent war, the Gulf War of 1990–1991, reflected the advent of the “revolution in military affairs” among U.S. forces and thus was more ne...

Donald C. Backer, James Aguirre, Judd D. Bowman, Richard Bradley, Chris L. Carilli, Steven R. Furlanetto, Lincoln J. Greenhill, Jacqueline N. Hewitt, Colin Lonsdale, Sterphen M. Ord, Aaron Parsons, & Alan Whitney 1University of California, Berkeley; [email protected]; 510-NGC-5128 2University of Pennsylvania 3California Institute of Technology 4National Radio Astronomy Observatory 5Uni...

Executive Summary: Studies of the nature of the first galaxies, and of the processes that led to their assembly and buildup, are of compelling importance. Not only did the first generation of galaxies likely reionize the universe, but they also were the seeds for the diverse population of today’s galaxies and the massive black holes that reside in them. Star formation in the first galaxies was ...

The classification of time series from photometric large scale surveys into variability types and the description of their properties is difficult for various reasons including but not limited to the irregular sampling, the usually few available photometric bands, and the diversity of variable objects. Furthermore, it can be seen that different physical processes may sometimes produce similar b...

The rate of survival of infants born extremely early — previously considered to be periviable (≤24 weeks) — has increased with advances in perinatal–neonatal care. However, concerns regarding higher rates of neurodevelopmental impairment among survivors have been raised. A precise interpretation of outcomes in periviable neonates requires an understanding of competing outcomes bias, differences...