The fossil record of insects documents a high proportion of modern higher-level taxa (67% for families), although this capture rate drops off considerably for lower-level taxa. This record is Lagerstatten-driven, and is deployed by complementary, parallel body- and trace-fossil components that...

It is often taken for granted that as systems evolve over time they tend to become more complex. But little is understood about the mechanisms that might cause evolution to favor increases in complexity over time. This paper proposes three means by which complexity tends to grow as systems...

The immune system uses many strategies to generate its enormous repertoire of diverse antibodies, but their relative importance is not understood. As part of a larger project to quantify their relative contributions, we have studied how the survival probability of an individual scales with the...

In the information contagion context, agents choose sequentially between two competing products, basing their decisions upon information obtained from a sample of previous adopters. The market shares that each product obtains depend upon the ture difference in performance between the products,...

Applications of Lagrange's method of undetermined mutipliers in physics and economics suggest some analogies between the two disciplinces. By using the work of E. T. Jaynes on information theory, the long standing problem of Maxwell's demon in thermodynamics can be cast as a constrained...

Crossover events along chromosomes do not occur independently, but influence the probably of other nearby events. The most common interaction between nearby crossover events is inhibitory:\enskip a crossover event tends to reduce the probability of other such events nearby, and this is called...

A simple model of self-organized learning with no classical (Hebbian) reinforcement is presented. Synaptic connections involved in mistakes are depressed. The model operates at a highly adaptive, probably critical, state reached by extremal dynamics similar to that of recent evolution models....

In theoretical studies of social interactions, we hypothesize a process and seek to deduce the implied outcomes. In inferential studies, we face an inverse logical problem. Given observations of outcomes and maintained assumptions, we seek to deduce the actual process generating the...

The dynamics of biological populations often appear quite complex, exhibiting considerable year-to-year variation in local abundances. One approach to dealing with ecological complexity is to reduce the system to one or a few species, for which meaningful equations can be written and even...

We resolve several long-standing open questions regarding the power of various types of finite-state automata to recognize "picture languages," i.e. sets of two-dimensional arrays of symbols. We show that the languages recognized by 4-way alternating finite-state automata (AFAs) are incomparable...