Elevated concentrations of inorganic sediment supply in streams may impair many biological functions. However, the contribution of exposure duration to the observed impacts has not been previously considered. We evaluated the effects of sediment pulse duration using 14 streamside flow-through experimental channels, each of which contained a naturally colonised invertebrate assemblage and 10 rainbow trout (Oncorhynchus mykiss) fry. Channels were exposed to fine sediment pulses of constant concentration but varied pulse duration (ranging from 0 to 6 h) every second day over 19 days. Total abundance of benthic invertebrate and family richness declined as sediment pulse duration increased. Invertebrate drift total abundance increased as pulse duration increased; however, family richness of drift decreased. Trout length and mass gain over the 19-day period was negatively correlated with pulse duration. Path analysis suggests that the direct effects of fine sediment on trout (impaired vision leading to reduced prey capture success and (or) increased metabolic costs from physiological stress) are more important to trout growth than indirect effects (decreased drift and benthic invertebrate richness and drift abundance).

Heterotopic ossifications of the TMJ may be seen in children with JIA and are associated with particularly severe TMJ arthritis, joint destruction, and pannus formation. Pathology from these joints suggests that the heterotopic ossification may result from multiple pathological processes.

No abstract

Advancing methods are leading to the discovery of genes associated with childhood autoimmune diseases. However, the genetic contribution to disease risk for any one gene remains less than 30% for most diseases, suggesting that pediatric autoimmunity is not primarily genetic in a classical sense. A combinatorial approach considering the contributions of multiple genes, mode of inheritance, and environmental influences will be required to fully understand the mechanisms of pathogenesis in pediatric autoimmune disease.

No abstract

lthough the history of a subject or of a time Torrey, the oldest of the three, earned his living should treat the parts played both by the "great" by teaching chemistry â€"at West Point, at Princeor by the well-knownâ€" and by lesser figures, it ton, and at the College of Physicians and Suris generally true that there are some few persons geons in New York. Although Torrey had close who stand out amongst the others and who give ties with many correspondents in Europe, he was, definition to the subject and time.par excellence, a botanist for North America. He Even the most cursory look at botany in North was from the 1820s involved with preparing the America during the nineteenth century shows pre-botanical reports for government-sponsored exeminent the triumvirateâ€" Asa Gray, John Tor-peditions and until after the Civil War plants rey, and George Engelmann. There were other from such expeditions went to Torrey, who had outstanding botanists at the middle of the cen-the overall responsibility for them. He prepared, turyâ€" one might mention W. S. Sullivant and for example, the final report on the botanical Edward Tuckerman â€" but it was Gray, Torrey, collections made by the Boundary Commission, and Engelmann who had the greatest effect upon which operated after the Mexican War. Torrey their adopted field. Their combined careers as was much less concerned than were Gray and botanistscover nearly seventy years. During this Engelmann in direct dealings with the private time, botany in North America developed from collectors active during the 1840s, but for many the simple collecting of plants and amassing of years it was he who would have the most direct data with consequent assignment of genera and connection with any official in Washington who species into Linnaean pigeonholes, into some-might be helpful to botany. thing like modern botany.Gray I see as the organizer among the three. I think, too, that examination of events in any From his arrival at Harvard in 1842, he was at field of science cannot be usefully done unless the center of botanical activities in the United seen against the background of contemporary po-States and he came to have the greatest breadth litical, social, and intellectual realities. It can be of interests. His first trip abroad in 1838-1839 done neither for the present nor for what might allowed him to make contacts and to open chanseem to have been a simpler and less complicated nels of communication that made Gray the intime. In any case, developments in botany in the ternationalist among American scientistsâ€" cer-United States during the middle of the nine-tainly among botanists. For thirty years Gray teenth century were pulled along by the political provided a one-man abstracting serviceâ€" preevents, and I have chosen to consider this time senting in the American Journal of Science and by looking at the relationship of botany to ex-Arts, ''Silliman's Journal," information about ploration in the American west and at the part botanical work in Europeâ€" news and reviews and played b...

No abstract

No abstract