PVM and MPI are often compared. These comparisons usually start with the unspoken assumption that PVM and MPI represent diierent solutions to the same problem. In this paper we show that, in fact, the two systems often are solving diierent problems. In cases where the problems do match but the solutions chosen by PVM and MPI are diierent, we explain the reasons for the diierences. Usually such ...

The abundance of sex and recombination is still one of the most puzzling questions in the theory of evolution: Most models find that recombination can evolve, but only under a limited range of parameters. Here we review the major models and supporting evidence, concentrating on recent approaches where more realistic assumptions help explain the evolution of sex and recombination under a wider p...

a dissertation on the prophylaxis and treatment, of the condition. Wrappers and Covers Their wrappings are drab and difficult to remove, so the journals accumulate on our desks in inconvenient piles and roll on to the floor. There is little incentive to make the effort of opening them. When opened they have a strong tendency to roll themselves up again. The covers are as drab as the wrappers. T...

Epididymal tumour incidence is at most 0.03% of all male cancers. It is an enigma why the human epididymis does not often succumb to cancer, when it expresses markers of stem and cancer cells, and constitutively expresses oncogenes, pro-proliferative and pro-angiogenic factors that allow tumour cells to escape immunosurveillance in cancer-prone tissues. The privileged position of the human epid...

Many biological proteins are observed to fold into one of a limited number of structural motifs. By considering the requirements imposed on proteins by their need to fold rapidly, and the ease with which such requirements can be fulfilled as a function of the native structure, we can explain why certain structures are repeatedly observed among proteins with negligible sequence similarity. This ...

Speech perception models with a fast phonological preprocessor (an FPP) require a uniform phonology throughout the speech community, because chunking errors would otherwise impede lexical access. The phonological constraints encapsulated in an FPP arise as regularities over the lexicon. However, different people know different words. A Monte Carlo simulation of vocabulary acquisition using the ...

Herein, we aim to show why the work on translationally (and otherwise) cold molecules has sparked so much inspiration--and anticipation--in both the physics and chemistry communities. We begin by discussing the basic features of cold molecules as implied by their de Broglie wavelengths, large compared with molecular dimensions. We juxtapose cold molecule and cold atom research and recount the c...

This master thesis is a part of a project conducted by the Centre of Speech Technology at the Department of Language, Speech and Music at the Royal Institute of Technology. The focus of this master thesis has been on how to make computerized language learning more entertaining and stimulating. Computer games in general can create an addictive and motivational encouraging stimulation for players...

We thank the Russell Sage Foundation for their generous support of this research.

According to the official U.S. measure of poverty, in 1995 the child poverty rate in this country was nearly 21%, compared with an adult poverty rate of 11%. This article explores why, according to the official measure, there are so many poor children. Working from the premise that children are poor because they live with poor adults, the reasons for adult poverty are reviewed. Both economic fo...