The 'expensive tissue hypothesis' predicts a size trade-off between the brain and other energetically costly organs. A specific version of this hypothesis, the 'expensive sexual tissue hypothesis', argues that selection for larger testes under sperm competition constrains brain size evolution. We show here that there is no general evolutionary trade-off between brain and testis mass in mammals....

Parasites that are molecular mimics express proteins which resemble host proteins. This resemblance facilitates immune evasion because the immune molecules with the specificity to react with the parasite also cross-react with the host's own proteins, and these lymphocytes are rare. Given this advantage, why are not most parasites molecular mimics? Here we explore potential factors that can sele...

The relationship between trade expansion and environmental protection has been characterised by two extreme viewpoints – promoting trade worsens environmental conditions and higher environmental standards impose an economic cost. Two conflicting hypothesis emerge from the debate. One manifestation of the above-described trade off is the hypothesis that increasing trade may encourage developing ...

A qualitative axiomatization of a generalization of expected utility theory is given in which the expected value of simple gambles is not necessarily the product of subjective probability and utility. Representation and uniqueness theorems for these generalized structures are derived for both Archimedean and nonarchimedean cases. It is also shown that a simple condition called distributivity is...

P and time are integral dimensions of virtually any decision. To treat them together, we consider the prospect of receiving outcome x with a probability p at time t. We define risk and time distance, and show that if these two distances are traded off linearly, then preferences are characterized by three functions: a value function, a probability discount rate function, and a psychological dist...

The idea that developing countries face a trade-off between poverty and inequality has had considerable influence on thinking about development policy. The experience of developing countries in the 1990s does not, however, reveal any sign of a systematic trade-off between measures of absolute poverty and relative inequality. Indeed, falling inequality tends to come with falling poverty incidenc...

Little is known about how humans solve the exploitation/exploration trade-off. In particular, the evidence for uncertainty-driven exploration is mixed. The current study proposes a novel hypothesis of exploration that helps reconcile prior findings that may seem contradictory at first. According to this hypothesis, uncertainty-driven exploration involves a dilemma between two motives: (i) to sp...

Time-cost trade-off is one of the most important subjects in project management and of interest to contractors. The goal of time-cost trade-off is sensivity analysis of project costs to changes in activity duration in order to obtain the best combination of activity duration decrease, in a way that the sum of project costs is minimized. In the heuristics presented in this area, time crashing is...

this paper tries to test the relationship between trade openness and economic growth in former soviet :union: countries after their independence in 1991. it has become an article of faith in most economic and political circles that opening up the economy to international trade will produce substantial benefits in terms of greater consumer choice and higher living standards. higher productivity ...