Mammals are characterised by their ability to provision offspring with milk, but lactation is normally restricted to females. Why do most males not share this trait? The morphological and physiological modifications necessary for male lactation are possible and, although restrictive, the ecological factors that could select for male lactation seem common enough. Until quite recently, there was ...

Partial types for the -calculus were introduced by Thatte in 1988 [8] as a means of typing objects that are not typable with simple types, such as heterogeneous lists and persistent data. In that paper he showed that type inference for partial types was semidecidable. Decidability remained open until quite recently, when O'Keefe and Wand [5] gave an exponential time algorithm for type inference...

Until recently, game-tree pathology (in which a deeper game-tree search results in worse play) has been thought to be quite rare. We provide an analysis that shows that every game should have some sections that are locally pathological, assuming that both players can potentially win the game. We also modify the minimax algorithm to recognize local pathologies in arbitrary games, and cut off sea...

Variation, the fuel that feeds evolutionary change, originates at the levels of both the genotype and the phenotype. Genetically identical organisms reared under different conditions may display quite distinct characteristics. Until recently, the types and sources of such phenotypic variation have been given little consideration in evolutionary theory. But a knowledge of the mechanisms and deve...

Optimization via simulation consists in applying iteratively two detached models until an optimality condition is reached: a simulation model for predicting the system performance and an optimization model for finding out the optimal solution. Mathematical programming representation has been recently used to describe the behavior of discrete event systems as well as their formal properties. Thi...

Although the first study on the efficacy of methotrexate in the treatment of psoriasis was reported in 1958, scientific evidence for this indication has been scant until quite recently. We now have new data on the pharmacokinetics and mechanism of action of methotrexate and new subcutaneous formulations that have improved the bioavailability, efficacy, and ease of administration of the drug. Th...

Bacterial chemotaxis, the movement of motile bacteria toward or away from chemicals, was discovered nearly a century ago by Engelmann (1) and Pfeffer (2,3). The subject was actively studied for about 50 years, but then there were very few reports until quite recently. For reviews of the literature up to about 1960, see Berg (4), Weibull (5), and Ziegler (6). The present review will restrict its...

Concavity trees have been known for quite some time as structural descriptors of 2-D shape; however, they haven’t been explored further until recently. This paper shows how 2-D shapes can be concisely, but reversibly, represented during concavity tree extraction. The representation can be exact, or approximate to a pre-set degree. This is equivalent to a lossless, or lossy compression of the im...

Until quite recently, the Chinese pension system was an enterprise-based, pay-as-you-go, defined benefit scheme. In 1995, the decision was made to shift to a multi-pillar scheme that included a second funded defined contribution pillar. The transition is proving difficult. This article outlines an alternative second pillar that may make more sense for China, a pay-as-you-go notional defined con...

Although they are widely distributed across kingdoms and are involved in a myriad of essential processes, until recently, repeat proteins have received little attention in comparison to globular proteins. As the name indicates, repeat proteins contain strings of tandem repeats of a basic structural element. In this respect, their construction is quite different from that of globular proteins, i...