After gene duplication, mutations cause the gene copies to diverge. The classical model predicts that these mutations will generally lead to the loss of function of one gene copy; rarely, new functions will be created and both duplicate genes are conserved. In contrast, under the subfunctionalization model both duplicates are preserved due to the partition of different functions between the duplicates. A recent study(1) provides support for the subfunctionalization model, identifying several expressed gene duplicates common to humans and mice that (...) contain regions conserved in one duplicate but variable in the other (and vice versa). We discuss both the methodology used in this study and also how gene phylogeny may lead to additional evidence for the importance of subfunctionalization in the evolution of new genes. BioEssays 23:873–876, 2001. © 2001 John Wiley & Sons, Inc. (shrink)

Consistent application of dialectical materialism leads Marxism-Leninism to the assertion that matter is infinite in its properties. However, the history of physics shows that the various levels of matter possess geometric dimensions that originate at the lowest level and continue through the others. The search for absolute natural constants -- which Planck called the most pleasant task of physics -- shows the conviction of the physicists that there is a limit to the parameters, a limit beyond which matter is no (...) longer divisible. (shrink)

A pO -algebra $${(L; f, \, ^{\star})}$$ is an algebra in which ( L ; f ) is an Ockham algebra, $${(L; \, ^{\star})}$$ is a p -algebra, and the unary operations f and $${^{\star}}$$ commute. Here we consider the endomorphism monoid of such an algebra. If $${(L; f, \, ^{\star})}$$ is a subdirectly irreducible pK 1,1 - algebra then every endomorphism $${\vartheta}$$ is a monomorphism or $${\vartheta^3 = \vartheta}$$ . When L is finite the endomorphism monoid of L is (...) regular, and we determine precisely when it is a Clifford monoid. (shrink)

I argue that Scotus's formal distinction is a mereological fusion relation rather than an identity relation. I construct mereological models which adequately represent Scotus's theory.