DISCUSSION: FINANCING AGRICULTURAL ECONOMICS RESEARCH AND EXTENSION IN THE SOUTHERN REGION

Teaching/Communication/Extension/Profession,

Light hadron properties with improved staggered quarks

Preliminary results from simulations with 2+1 dynamical quark flavors at a lattice spacing of 0.09 fm are combined with earlier results at a=0.13 fm. We examine the approach to the continuum limit and investigate the dependence of the pseudoscalar masses and decay constants as the sea and valence quark masses are separately varied.Comment: Lattice2002(spectrum

Wanted, an Anthrax vaccine: Dead or Alive?

It has been more than 100 years since the realization that microbes are capable of causing disease. In that time, we have learned a great deal as to how each organism has adapted to the immune system so as to avoid elimination. As well, we have also learned an immense amount since Louis Pasteur first proposed that the solution to infectious diseases was to culture the microbes and attenuate their virulence, so as to use them as vaccines. From the optimism and promise of the 19(th )century and immunization as the ultimate answer to the invasion by the microbial world, to the scientific realities of the 21(st )century, it is of interest to retrace the steps of the earliest microbiologists cum immunologists, to realize how far we've come, as well as how far we yet have to go. This editorial focuses on the history of anthrax as a microbial disease, and the earliest efforts at producing a vaccine for its prevention

Monopole action from vacuum configurations in compact QED

It is possible to derive a monopole action from vacuum configurations obtained in Monte-Carlo simulations extending the method developed by Swendsen. We apply the method to compact QED both in the Villain and in the Wilson forms. The action of the natural monopoles in the Villain case is in fairly good agreement with that derived by the exact dual transformation. Comparing the monopole actions, we find (1) the DeGrand-Toussaint monopole definition may be useful for $\beta_V$ larger than about 0.5, (2) the Villain model well approximates the Wilson one for $\beta$ smaller than $\beta_c$ and (3) in the Wilson action the monopole condensation occurs in the confinement phase and $\beta_c$ may be explained by the energy-entropy balance of monopole loops like in the Villain case.Comment: 12 Pages+7 figures, KANAZAWA 94-1

Dynamical Wilson fermions and the problem of the chiral limit in compact lattice QED

We compare the approach to the chiral transition line ~\kappa_c(\bt)~ in quenched and full compact lattice QED with Wilson fermions within the confinement phase, especially in the pseudoscalar sector of the theory. We show that in the strong coupling limit ($\beta =0$) the quenched theory is a good approximation to the full one, in contrast to the case of $\beta =0.8$. At the larger $\beta$-value the transition in the full theory is inconsistent with the zero--mass limit of the pseudoscalar particle, thus prohibiting the definition of a chiral limit.Comment: 13 pages LaTeX (epsf), all figures include

Using Spreadsheets to Enhance Understanding of Number Theory

Computer spreadsheets can help elementary school students explore concepts in number theory. We describe a spreadsheet program that can generate all the factors of an integer. To understand how the spreadsheet solves these problems, we use the metaphor of a robot. The robot must interpret data from the real world and respond effectively. Although non-engineers may not understand the details, they can see what the robot types, and can discuss how the robot makes decisions. Students can see mathematical knowledge being used. The robot can add, subtract, multiply, and divide, and determine whether a number is an integer. Based upon this knowledge, the robot can determine the factors of a number. In one method, the robot follows the rules blindly, testing each possible factor. In the second method, the robot uses knowledge of number theory to solve the problem much more efficiently. The activities are extended to include the topic of prime numbers. In the first method, the robot determines that 97 is prime by performing all possible divisions starting with 1. Although the answer is correct, the method is inefficient. It is much more effective to apply knowledge of number theory to determine that only the prime numbers less than ten need to be tested. As a result, only four divisions, rather than 97, are needed to determine the correct answer. With the power of spreadsheets, students can observe different methods that get the correct answer, and discover those that are most efficient.Cockrell School of Engineerin

Scaling of Pseudo-Critical Couplings in Two-Flavour QCD

We study the scaling behaviour of the pseudo-critical couplings for the chiral phase transition in two-flavour QCD. We show that all existing results from lattice simulations on lattices with temporal extent $N_\tau = 4$, 6 and 8 can be mapped onto a universal scaling curve. The relevant combination of critical exponents, $\beta\delta$, is consistent with the scaling behaviour expected for a second order phase transition with $O(4)$ exponents. At present, scaling according to the $O(2)$ symmetry group can, however, not be ruled out.Comment: 8 pages, NSF-ITP 93-12