Taxation and the Household

Previous analyses of demand systems and the welfare effects of taxing male and female labour supplies suppress the analysis of household resource allocation by assuming a household utility function. To analyse the implications of assuming this is not the case, we construct a simple but fairly general model of household resource allocation and use the properties of the equilibrium of this model to characterise the effects of tax policy on individual utilities, as determined by the household resource allocation proces

A Fundamental Domain for V_3

We describe a fundamental domain for the punctured Riemann surface $V_{3,m}$ which parametrises (up to M\"obius conjugacy) the set of quadratic rational maps with numbered critical points, such that the first critical point has period three, and such that the second critical point is not mapped in $m$ iterates or less to the periodic orbit of the first. This gives, in turn, a description, up to topological conjugacy, of all dynamics in all type III hyperbolic components in $V_{3}$, and gives indications of a topological model for $V_{3}$, together with the hyperbolic components contained in it.Comment: 120 page

Delayed Germination of Seeds: A Look at the Effects of Adult Longevity, the Timing of Reproduction, and Population Age/Stage Structure

The effects of adult longevity, the timing of reproduction, and population age/stage structure on the evolution of seed dormancy are explored in both constant and variable environment models. In the constant environment models complete germination is the evolutionarily stable strategy (ESS) regardless of adult longevity. Incorporating a cost of reproduction on subsequent survival does not alter this result. In contrast, in a variable environment changes in adult longevity can exert a strong selection pressure against seed dormancy. Incorporating a cost of reproduction for iteroparous species reduces adult longevity, which selects for more seed dormancy. The magnitude of the change in ESS germination probability depends on several factors, including which life-history stage is variable (e.g., fecundity, seedling survival), whether seeds can detect favorable sites for establishment, and the age/stage structure of the population. In general, increases in adult longevity select against seed dormancy, but exceptions to this pattern are discussed. The idea that established plant traits are uncoupled from those of the regenerative phase, as assumed by J. P. Grime's competition-stress-ruderal model, is considered critically

Null Models and Dispersal Distributions: A Comment on an Article by Caley

[FIRST PARAGRAPH] In a recent article Caley (1991) outlined a null model for dispersal distributions against which he suggested empirical data should be compared. He first presented Waser's geometric model (Waser 1985), which can be derived as follows: Dispersing individuals move in a straight line from the natal site and settle in the first unoccupied site they encounter. If unoccupied sites occur independently at random with probability t as a result of turnover within the habitat, then the distribution of dispersal distances will follow a geometric distribution in which the probability of settling at distance i is given by p(i) = t(l - t)' for i = 0, 1,2,3,. . . continues.

Man's transportation to space

Saturn i, saturn ib, and saturn v launch vehicle