A Comment on \u27Does the Aggregate Demand Curve Suffer from the Fallacy of Composition\u27

Commentary on Does the Aggregate Demand Curve Suffer From the Fallacy of Composition, by Ira Saltz, Pat Cantrell, and Joseph Horton, is provided

The Precautionary Principle and Radiation Protection

The authors examine the application of the precautionary principle through a case study of ionizing radiation control and suggest a reevaluation of current radiation safety standards and practices

Senator Kerry on Corporate Tax Reform: Right Diagnosis, Wrong Prescription

Senator John Kerry has proposed a major overhaul in corporate taxation, with the goal of persuading multinational companies (MNCs) to employ more workers at home and fewer abroad. Kerry has correctly emphasized that domestic production is often taxed at a higher rate than production abroad, but his prescriptions will not boost US jobs.

The genus Sipha Passerini (Hemiptera: Aphididae) in North America

Five species of the aphid genus Sipha Passerini (Hemiptera: Aphididae) are reported in North America and are reviewed herein. Of these species, three are adventive species and include: Sipha elegans del Guercio, Sipha glyceriae (Kaltenbach), and Sipha maydis Passerini. Sipha maydis was discovered in California in 2007 and now has been found in Georgia. The genus also includes two native species: Sipha agropyronensis (Gillette) and Sipha flava (Forbes). Sipha maydis can be distinguished easily from all the other species in the genus that occur in North America because it is black. All the species except S. agropyronensis have been implicated in damage to crop plants. A key to the apterae and alatae of Sipha found in North America is included

Effects of nonlinear aerodynamics and static aeroelasticity on mission performance calculations for a fighter aircraft

During conceptual design studies of advanced aircraft, the usual practice is to use linear theory to calculate the aerodynamic characteristics of candidate rigid (nonflexible) geometric external shapes. Recent developments and improvements in computational methods, especially computational fluid dynamics (CFD), provide significantly improved capability to generate detailed analysis data for the use of all disciplines involved in the evaluation of a proposed aircraft design. A multidisciplinary application of such analysis methods to calculate the effects of nonlinear aerodynamics and static aeroelasticity on the mission performance of a fighter aircraft concept is described. The aircraft configuration selected for study was defined in a previous study using linear aerodynamics and rigid geometry. The results from the previous study are used as a basis of comparison for the data generated herein. Aerodynamic characteristics are calculated using two different nonlinear theories, potential flow and rotational (Euler) flow. The aerodynamic calculations are performed in an iterative procedure with an equivalent plate structural analysis method to obtain lift and drag data for a flexible (nonrigid) aircraft. These static aeroelastic data are then used in calculating the combat and mission performance characteristics of the aircraft

Wind tunnel performance results of an aeroelastically scaled 2/9 model of the PTA flight test prop-fan

High speed wind tunnel aerodynamic performance tests of the SR-7A advanced prop-fan have been completed in support of the Prop-Fan Test Assessment (PTA) flight test program. The test showed that the SR-7A model performed aerodynamically very well. At the cruise design condition, the SR-7A prop fan had a high measured net efficiency of 79.3 percent

Modifications to the rapid melt/rapid quench and transparent polymer video furnaces for the KC-135

Given here is a summary of tasks performed on two furnace systems, the Transparent Polymer (TPF) and the Rapid Melt/Rapid Quench (RMRQ) furnaces, to be used aboard NASA's KC-135. It was determined that major changes were needed for both furnaces to operate according to the scientific investigators' experiment parameters. Discussed here are what the problems were, what was required to solve the problems, and possible future enhancements. It was determined that the enhancements would be required for the furnaces to perform at their optimal levels. Services provided include hardware and software modifications, Safety DataPackage documentation, ground based testing, transportation to and from Ellington Air Field, operation of hardware during KC-135 flights, and post-flight data processing

FNAS modify matric and transparent experiments

Monotectic alloy materials are created by rapid melt/rapid solidification processing on the NASA KC-135. Separation of the uniform liquid into two liquids may occur by either of two processes; spinodal decomposition or nucleation followed by growth. In the first case, the liquid is unstable to composition waves, which form and grow, giving liquids of two different compositions. In the latter process discrete particles of the second liquid phase form via thermal fluctuations and then grow by diffusion. The two processes are very different, with the determining process being dictated by temperature, composition, and thermodynamic characteristics of the alloy. The first two quantities are process variables, while the third is determined by electronic interactions between the atoms in the alloy. In either case the initial alloy decomposition is followed by coarsening, resulting in growth of the particle size at nearly constant volume fraction. In particular, reduced gravity experiments on monotectic solutions have shown a number of interesting results in the KC-135. Monotectic solutions exhibit a miscibility gap in the liquid state, and consequently, gravity driven forces can dominate the solidification parameters at 1 g. In reduced gravity however, the distribution of the phases is different, resulting in new and interesting microstructures. The Rapid Melt/Rapid Quench Furnace allows one to melt a sample and resolidify it in one parabola of the KC-135's flight path, thus eliminating any accumulative influence of multiple parabolas to affect the microstructure of the material

The U.S. system for measuring cross-border investment in securities: a primer with a discussion of recent developments

The tremendous growth in cross-border securities investment in recent years has called attention to the systems used by the United States and other countries to measure international securities flows and holdings. Ideally, the data gathered by the United States could tell us the extent to which foreign investors hold U.S. securities, the types of securities held, and the countries in which the securities are held, for example, and could identify trends in investment. This article looks at how well the data shed light on these topics. Special attention is given to the system's design and the implications of the design for data analysis. Also discussed are anticipated changes to the system and international efforts to improve data collection systems worldwide.International finance ; Securities