Commentary on Trends in the aggregate labor force

Labor supply

Spacecraft active thermal control technology status

Four advanced space radiator concepts that were pursued in an integrated effort to develop multi-mission-use and low cost heat rejection systems which can overcome the limitations of current radiator systems are briefly discussed and described. Also, in order to establish a firm background to compare the advanced space radiator concepts, the Orbiter active thermal control system is also briefly described

Monetary policy and learning: Some implications for policy and research

In March 2003 the Federal Reserve Bank of Atlanta hosted a conference focusing on the relationship between monetary policy and learning. The conference papers and discussions are part of an emerging literature that introduces learning-about the economy or the model used by policymakers-into dynamic macroeconomic models. In some models, monetary policymakers learn about how the economy works while in others private agents learn about the model(s) the central bank uses to formulate monetary policy. ; This article outlines key issues, raised in a 1999 book by Thomas Sargent, about how to interpret monetary policy behavior and economic performance over the past thirty years using the Phillips curve framework and different assumptions about learning. To a large extent, several conference papers follow from Sargent's work. Some conference papers focus on understanding recent inflation history, attempting to detect monetary policy's role in generating the recent, more benign inflation performance. Other conference papers investigate the role of learning behavior in a variety of settings. The article outlines the implications from some of the papers. ; Finally, the article describes economic literature relating to central bank transparency, its relevance for effective communication to the public about monetary policy, and its likely role in future learning models. Through the transparency discussion, the article foreshadows Lars Svensson's keynote address at the conference (reprinted here), citing it as a "suggested user's guide for monetary policymakers to improve policy effectiveness."Monetary policy

Order of acquisition in learning perceptual categories: a laboratory analogue of the age-of-acquisition effect?

In the age-of-acquisition (AoA) effect, an advantage for recognition and production is found for items learned early in life, as compared with items learned later. In this laboratory analogue, participants learned to categorize novel random checkerboard stimuli. Some stimuli were presented from the onset of training; others were introduced later. At test, when early and late stimuli had equal cumulative frequency, early stimuli were classified significantly more quickly. Because stimuli were randomly assigned to be introduced either early or late, we can conclude that early stimuli were categorized more quickly because of their order of acquisition. This finding suggests that age- or order-of-acquisition effects are a general property of any learning system

An investigation of current sheet structure in a cylindrical Z-pinch

Structure of propagating current sheet in large radius cylindrical pinch discharg

Groundwater Resources in the Saline Valley Conservancy District, Saline and Gallatin Counties, Illinois

published or submitted for publicationis peer reviewedOpe

Direction Judgement Errors in Perspective Displays

Spatial information transfer characteristics of perspective situation displays were investigated by having eight subjects judge the directions of displayed targets relative to a fixed position in the center of computer generated perspective scenes. Their errors in judging azimuth angles varied sinusoidally with the azimuth of the targets. Errors alternated between clockwise and counterclock wise from one direction quadrant to the next. As the perspective geometry was varied between telephoto lens and wide angle lens views, the direction of error gradually reversed in all quadrants. The results can be explained by systematic differences between the three-dimensional stimulus angles and the perspective projections of those angles onto the display screen

Japan's new security agenda

New Japanese Prime Minister Shinzō Abe has only been in office since late September, but already the outlines of his administration are becoming clearer, both in expected and unexpected directions. Abe’s administration is proving to be conservative and revisionist, and even more so than that of his predecessor Junichirō Koizumi. Abe has certainly moved to improve ties with China and South Korea—Beijing and Seoul the October destinations for his first overseas visits within two weeks of taking power—and thereby to limit the damage wrought by Koizumi’s visits to Yasukuni Shrine and bilateral wrangling over Japan’s colonial history. However, the general thrust of Abe’s diplomacy is built upon much of the legacy left by Koizumi, and is attempting to shift it on to a yet more pro-active and assertive path

Linearisation instability of gravity waves?

Gravity waves in irrotational dust spacetimes are characterised by nonzero magnetic Weyl tensor $H_{ab}$. In the linearised theory, the divergence of $H_{ab}$ is set to zero. Recently Lesame et al. [Phys. Rev. D {\bf 53}, 738 (1996)] presented an argument to show that, in the exact nonlinear theory, $div H=0$ forces $H_{ab}=0$, thus implying a linearisation instability for gravity waves interacting with matter. However a sign error in the equations invalidates their conclusion. Bianchi type V spacetimes are shown to include examples with $div H=0\neq H_{ab}$. An improved covariant formalism is used to show that in a generic irrotational dust spacetime, the covariant constraint equations are preserved under evolution. It is shown elsewhere that \mbox{div} H=0 does not generate further conditions.Comment: 8 pages Revtex; to appear Phys. Rev.