Teaching statistical physics by thinking about models and algorithms

We discuss several ways of illustrating fundamental concepts in statistical and thermal physics by considering various models and algorithms. We emphasize the importance of replacing students' incomplete mental images by models that are physically accurate. In some cases it is sufficient to discuss the results of an algorithm or the behavior of a model rather than having students write a program.Comment: 21 pages, 4 figures, submitted to the American Journal of Physic

Can Heavy WIMPs Be Captured by the Earth?

If weakly interacting massive particles (WIMPs) in bound solar orbits are systematically driven into the Sun by solar-system resonances (as Farinella et al. have shown is the case for many Earth-crossing asteroids), then the capture of high-mass WIMPs by the Earth would be affected dramatically because high-mass WIMPs are captured primarily from bound orbits. WIMP capture would be eliminated for M_x>630 GeV and would be highly suppressed for M_x>~150 GeV. Annihilation of captured WIMPs and anti-WIMPs is expected to give rise to neutrinos coming from the Earth's center. The absence of such a neutrino signal has been used to place limits on WIMP parameters. At present, one does not know if typical WIMP orbits are in fact affected by these resonances. Until this question is investigated and resolved, one must (conservatively) assume that they are. Hence, limits on high-mass WIMP parameters are significantly weaker than previously believed.Comment: 8 pages + 1 figure. Submitted to Ap

How good are projection methods for convex feasibility problems?

We consider simple projection methods for solving convex feasibility problems. Both successive and sequential methods are considered, and heuristics to improve these are suggested. Unfortunately, particularly given the large literature which might make one think otherwise, numerical tests indicate that in general none of the variants considered are especially effective or competitive with more sophisticated alternatives

Lax Operator for the Quantised Orthosymplectic Superalgebra U_q[osp(2|n)]

Each quantum superalgebra is a quasi-triangular Hopf superalgebra, so contains a \textit{universal $R$-matrix} in the tensor product algebra which satisfies the Yang-Baxter equation. Applying the vector representation $\pi$, which acts on the vector module $V$, to one side of a universal $R$-matrix gives a Lax operator. In this paper a Lax operator is constructed for the $C$-type quantum superalgebras $U_q[osp(2|n)]$. This can in turn be used to find a solution to the Yang-Baxter equation acting on $V \otimes V \otimes W$ where $W$ is an arbitrary $U_q[osp(2|n)]$ module. The case $W=V$ is included here as an example.Comment: 15 page

Distinguishing NAFTA from the peso crisis

North American Free Trade Agreement ; Financial crises - Mexico ; Devaluation of currency ; Peso, Mexican

The large scale microelectronics Computer-Aided Design and Test (CADAT) system

The CADAT system consists of a number of computer programs written in FORTRAN that provide the capability to simulate, lay out, analyze, and create the artwork for large scale microelectronics. The function of each software component of the system is described with references to specific documentation for each software component

Real trade-weighted value of the dollar holds, despite fall against the yen and mark

International trade

Mexico's crisis: looking back to assess the future

Mexico's most recent economic crisis took many in the international business community by surprise. In early December 1994, the Blue Chip consensus forecast for 1995 Mexican real GDP growth was 3.8 percent. A few weeks later, on December 20, the devaluation of the Mexican peso rocked international financial markets. What first appeared to be a minor correction in Mexico's nominal exchange rate quickly developed into a broader financial crunch felt in and outside Mexico. The Mexican government now expects the country's real GDP to fall about 3 percent in 1995; some private economists suggest an even greater decline.Gross domestic product ; Financial crises - Mexico ; Mexico

Has NAFTA changed North American trade?

The controversy over the success or failure of NAFTA is now bleeding over into discussion about the benefits of extending the trade accord to other countries in the Western Hemisphere. The NAFTA debate has typically focused on its impact on employment. But to understand the overall economic effects of NAFTA, it is important to first determine its impact on trade. In this article, David Gould explores NAFTA's effects on North America's trading patterns since its implementation in 1994. He finds that although it is difficult to distinguish any effect of NAFTA on trade between Canada and Mexico or Canada and the United States, trade between the United States and Mexico has significantly increased since 1994.North American Free Trade Agreement ; Free trade

Does the choice of nominal anchor matter?

The conventional wisdom on nominal anchors is that exchange rate-based inflation stabilizations lead to economic booms while monetary-based stabilizations lead to recessions. This study finds strong evidence against this view. Rather than determining the path of economic growth, the choice of nominal anchor appears to be endogenously determined by the state of the economy. To peg or manage the exchange rate, a high level of international reserves is important, especially when a government's credibility is low after a period of high inflation. After controlling for the level of international reserves and the rate of inflation, growth after monetary-based stabilizations does not significantly differ from that following exchange rate-based stabilizations. ; Economic Research Working Paper 9914Inflation (Finance)