Near-Infrared Broad-Line Profiles In Low-Redshift QSOs

We present near-infrared and optical spectrophotometry of six low-redshift QSOs. The integrated Pa-alpha/H-alpha-ratios cluster near the value 0.1, with one exception having a larger ratio consistent with other evidence of reddening. At least two of the Pa-alpha/H-alpha-profile ratios decrease with observed velocity. We discuss some implications for the dynamics of the broad-line region and this ratio's usefulness as a reddening indicator. We also present a spectrum of the He I-lambda-10830, Pa-lambda-blend of 1226 + 023. The He I/H-alpha-profile ratio shows marginal evidence for decreasing with observed velocity, which is consistent with the interpretation for the Pa-alpha/H-alpha-profile ratios.NSF 84-14652McDonald Observator

Globalization and the benefits of trade

Globalization involves increasing integration of economies around the world, from the national to the most local levels, thereby promoting international trade in goods and services and cross-border movement of information, technology, people, and investments. This article examines the benefits and costs to the U.S. and other countries.Globalization ; International trade

Rural Towns Don't Have to Dry Up and Blow Away

Agricultural and Food Policy,

Whither Food Aid?

Agricultural and Food Policy,

Procedure for Determining Speed and Climbing Performance of Airships

The procedure for obtaining air-speed and rate-of-climb measurements in performance tests of airships is described. Two methods of obtaining speed measurements, one by means of instruments in the airship and the other by flight over a measured ground course, are explained. Instruments, their calibrations, necessary correction factors, observations, and calculations are detailed for each method, and also for the rate-of-climb tests. A method of correction for the effect on density of moist air and a description of other methods of speed course testing are appended

HOST structural analysis program overview

Hot-section components of aircraft gas turbine engines are subjected to severe thermal structural loading conditions, especially during the startup and takeoff portions of the engine cycle. The most severe and damaging stresses and strains are those induced by the steep thermal gradients induced during the startup transient. These transient stresses and strains are also the most difficult to predict, in part because the temperature gradients and distributions are not well known or readily predictable and, in part, because the cyclic elastic-viscoplastic behavior of the materials at these extremes of temperature and strain are not well known or readily predictable. A broad spectrum of structures related technology programs is underway to address these deficiencies at the basic as well as the applied level. The three key program elements in the HOST structural analysis program are computations, constitutive modeling, and experiments for each research activity. Also shown are tables summarizing each of the activities

Why Some People Question Our Farm Programs

Agricultural and Food Policy,

America’s largest classroom: Expanding the role of education in our parks

An introduction to this issue's set of theme papers, which were inspired by the new book America’s Largest Classroom: What We Learn from Our National Parks (University of California Press, 2020). These papers explore innovations in education and interpretation in the US National Park Service