A model for evolution and extinction

We present a model for evolution and extinction in large ecosystems. The model incorporates the effects of interactions between species and the influences of abiotic environmental factors. We study the properties of the model by approximate analytic solution and also by numerical simulation, and use it to make predictions about the distribution of extinctions and species lifetimes that we would expect to see in real ecosystems. It should be possible to test these predictions against the fossil record. The model indicates that a possible mechanism for mass extinction is the coincidence of a large coevolutionary avalanche in the ecosystem with a severe environmental disturbance.Comment: Postscript (compressed etc. using uufiles), 16 pages, with 15 embedded figure

Building English Explanations from Function Descriptions

This report describes research done at the Artificial Intelligence Laboratory of the Massachusetts Institute of Technology. Support for the laboratory's artificial intelligence research is provided in part by the Office of Naval Research under Office of Naval Research contract N00014-75-C-0389.An explanatory component is an important ingredient in any complex AI system. A simple generative scheme to build descriptive phrases from Lisp function calls can produce respectable explanations if explanation generators capitalize on the function decomposition reflected in Lisp programs.MIT Artificial Intelligence Laboratory Department of Defense Office of Naval Researc

Leadbetter

A satirical comic about the rogue, right-wing, gun-loving US Senator Leadbetter, who wins the presidency and installs a dictatorship, which solves all social problems with extreme prejudice

An intensity-expansion method to treat non-stationary time series: an application to the distance between prime numbers

We study the fractal properties of the distances between consecutive primes. The distance sequence is found to be well described by a non-stationary exponential probability distribution. We propose an intensity-expansion method to treat this non-stationarity and we find that the statistics underlying the distance between consecutive primes is Gaussian and that, by transforming the distance sequence into a stationary one, the range of Gaussian randomness of the sequence increases.Comment: 11 pages, 7 figures, in press on 'Chaos, Solitons & Fractals

The Wigner caustic on shell and singularities of odd functions

We study the Wigner caustic on shell of a Lagrangian submanifold L of affine symplectic space. We present the physical motivation for studying singularities of the Wigner caustic on shell and present its mathematical definition in terms of a generating family. Because such a generating family is an odd deformation of an odd function, we study simple singularities in the category of odd functions and their odd versal deformations, applying these results to classify the singularities of the Wigner caustic on shell, interpreting these singularities in terms of the local geometry of L.Comment: 24 page

Techniques of Teaching Adult Learners

This project is the compiling of class discussion related to characteristics of adult learners from a course Teaching the Adult Learner–ADE 4382 offered through the University of Central Florida. A Web-based course was offered during the spring semester 2000 and taught by Dr. Larry Hudson. The course can be accessed at http://reach.ucf.edu/~ade438