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Republicans in the United States are promoting legislation that would insist on scientific risk analysis before any tightening of environmental regulation. The proposals are not acceptable.
Is scientific risk assessment the best way to make decisions about environmental threats? Republicans in the US Congress, and many in industry, think it is. Others — including environmentalists—are less convinced.
The Standard Model of particle physics has it that quarks are fundamental particles. But an experiment that echoes two past revolutions in our understanding of matter might hint instead at an even smaller level of structure.
Functional studies seem now to confirm, as first suggested by E. Geoffrey Saint-Hilaire in 1822, that there was an inversion of the dorsoventral axis during animal evolution. A conserved system of extracellular signals provides positional information for the allocation of embryonic cells to specific tissue types both in Drosophila and vertebrates; the ventral region of Drosophila is homologous to the dorsal side of the vertebrate. Developmental studies are now revealing some of the characteristics of the ancestral animal that gave rise to the arthropod and mammalian lineages, for which we propose the name Urbilateria.
