Sources of Business Cycle Fluctuations

What shocks account for the business cycle frequency and long run movements of output and prices? This paper addresses this question using the identifying assumption that only supply shocks, such as shocks to technology, oil prices, and labor supply affect output in the long run. Real and monetary aggregate demand shocks can affect output, but only in the short run. This assumption sufficiently restricts the reduced form of key macroeconomic variables to allow estimation of the shocks and their effect on output and price at all frequencies. Aggregate demand shocks account for about twenty to thirty percent of output fluctuations at business cycle frequencies. Technological shocks account for about one-quarter of cyclical fluctuations, and about one-third of output's variance at low frequencies. Shocks to oil prices are important in explaining episodes in the 1970's and 1980's. Shocks that permanently affect labor input account for the balance of fluctuations in output, namely, about half of its variance at all frequencies.

The reionization of the universe: The feedback of galaxy formation on the intergalactic medium

The thermal and ionization evolution of a uniform intergalactic medium (IGM) composed of H and He, undergoing reionization, including the mean effect of gas clumps embedded in a smoothly distributed ambient gas were calculated. The rate equations for ionization and recombination were solved together with the equations of energy conservation, including the effects of cosmological expansion, radiative and Compton cooling, and the diffuse flux emitted by the gas, and radiative transfer. The contribution to the continuum opacity of the universe due to the observed quasar absorption line clouds (QALC'S) were included. A variety of sources of photoionization, including quasars and primeval galaxies, as well as the possibility that hydrodynamical processes deposit thermal energy in the IGM were considered. Applications of these calculations including the evolution of the Ly-alpha forest clouds are described. A self-consistent treatment of the thermal and ionization history of the intergalactic medium (IGM) must take account of the growth of structure in the universe, since the mean density of the IGM corresponds primarily to the time-varying uncollapsed fraction of the baryon-electron component of the matter, and the collapsed fraction, in turn, can have a feedback effect on this uncollapsed fraction by releasing ionizing radiation and thermal energy and by contributing to the opacity of the universe. The coupled evolution of the IGM and the emerging structure with a special focus on the reionization of the IGM, which is believed to have been completed by some redshift z is approximately greater than 4, as inferred from the absence of the Gunn-Peterson effect in the spectra of high z quasars, are studied. The results and implications of detailed, numerical calculations of the thermal and ionization balance and radiative transfer in a uniform IGM of H and He, including the mean effect of an evolving distribution of gas clumps embedded in a smoothly distributed ambient gas is described

How do Poor People Adapt to Weather Variability and Natural Disasters Today?

human development, climate change

Less Debt, More Equity: Lowering Student Debt While Closing the Black-White Wealth Gap

The dramatic increase in wealth inequality over the past several decades now forms the backdrop for many of today's most pressing public policy debates. Currently, the top 1 percent of U.S. households controls 42 percent of the nation's wealth, and nearly half of the wealth accumulated over the past 30 years has gone to the top 0.1 percent. Simultaneously, the wealth held by the bottom 90 percent of U.S. households continues to shrink, just as people of color are a growing percentage of the U.S. population. These trends have converged to produce a wealth divide that is apparent not just by class, but by race as well. The average white family owns $13 for every$1 owned by a typical Black family, and $10 for every$1 owned by the typical Latino family.This analysis uses the Racial Wealth Audit, a framework developed by the Institute on Assets and Social Policy (IASP) to assess the impact of public policy on the wealth gap between white and Black households. We use the framework to model the impact of various student debt relief policies to identify the approaches most likely to reduce inequities in wealth by race, as opposed to exacerbating existing inequities. We focus specifically on the Black-white wealth gap both because of the historic roots of inequality described above, and because student debt (in the form of borrowing rates and levels) seems to be contributing to wealth disparities between Black and white young adults, in particular

Markov Chains for Computer Music Generation

Random generation of music goes back at least to the 1700s with the introduction of Musical Dice Games. More recently, Markov chain models have been used as a way of extracting information from a piece of music and generating new music. We explain this approach and give Python code for using it to first draw out a model of the music and then create new music with that model