Recent computer models of landform evolution have focused on surface processes of river networks and hillslopes (e.g., Ahnert, 1976; Kirkby, 1986; Willgoose et al., 1991a, b; Koltermann and Gorelick, 1992; Howard, 1994; Howard et al., 1994; Smith et al., 1997). Most of these models are based on complicated differential equations that are difficult to solve. Chase (1992) developed a cellular aut...

We tested for the occurrence of Bergmann's rule, the pattern of increasing body size with latitude, and Rapoport's rule, the positive relationship between geographical range size and latitude, in 34 lineages of Liolaemus lizards that occupy arid regions of the Andean foothills. We tested the climatic-variability hypothesis (CVH) by examining the relationship between thermal tolerance breadth an...

The evidence that climate warming is changing the distribution of Ixodes ticks and the pathogens they transmit is reviewed and evaluated. The primary approaches are either phenomenological, which typically assume that climate alone limits current and future distributions, or mechanistic, asking which tick-demographic parameters are affected by specific abiotic conditions. Both approaches have p...

A reverence for ancestors that has pre-occupied humans since time immemorial persists to the present. Reconstructing ancestry is the focus of many biological studies but failure to distinguish between present-day descendants and long-dead ancestors has led to incorrect interpretation of phylogenetic trees. This has resulted in erroneous reconstruction of traits such as morphology and ancestral ...

This paper discusses the need for a more integrated approach to modelling changes in climate and crops, and some of the challenges posed by this. While changes in atmospheric composition are expected to exert an increasing radiative forcing of climate change leading to further warming of global mean temperatures and shifts in precipitation patterns, these are not the only climatic processes whi...

abstract in this study we have used the monthly data resulted from the calculation of temperature and precipitation for a 52-year period (1951-2003). the doubling effect of carbon dioxide ( ) on temperature and precipitation was modeled as the most important climatic parameters. the resulting hythergraph and ambrothermic models for tabriz indicate monthly increases of temperature and precipitat...