On viruses, sex, and motherhood

Sex in Bacteria and Viruses

In vitro fertilization, surrogate motherhood, and sex organ transplants.

The efforts of Drs. Patrick C. Steptoe and Robert G. Edwards in England culminated in the birth of Louise Brown on July 25, 1978, as a result of in vitro fertilization and reimplantation of the human embryo into the mother's womb.' The same investigators later reported the birth of a boy by this technique. 2 Since then, several hundred babies have been born by this methodology. More recently, f...

on semihypergroups and hypergroups

in this thesis, first the notion of weak mutual associativity (w.m.a.) and the necessary and sufficient condition for a $(l,gamma)$-associated hypersemigroup $(h, ast)$ derived from some family of $lesssim$-preordered semigroups to be a hypergroup, are given. second, by proving the fact that the concrete categories, semihypergroups and hypergroups have not free objects we will introduce t...

Essays on Motherhood and Female Labour Supply

Segregation of the labour market into a family-friendly and a non-family-friendly sector implies that women self-select into sectors depending on institutional constraints, preferences for family-friendly working conditions and expected wage differences. We take this sector dimension into account and find a severe penalty after birth-related leave in the non-familyfriendly sector, so that women...

Sex frees viruses from genetic 'ratchet'.

ARNHEM, THE NETHERLANDS --It's probably the only question that the celebrated sexologists Masters and Johnson didn't ask: How did sex originate? Evolutionary biologists, however, have puzzled for much of this century over why so much of life has evolved the ability to shuffle genetic material between individuals--the essence of sexual reproduction. "It must confer some benefit," Lin Chao, an ev...