Uses, lead historical

If this is a correct analysis of it, then the chief problem with Brush s overall account—aside from any issue about the historical evidence in its favour—is that, by agreeing with Maher and Lipton that the novel predictions counted more while denying that they counted sufficiently more to outweigh the total effect of the accommodations, it ends up in no man s land. Brush may have an explanation for why special attention should have been paid to the predictive successes (they carried a lot of impact per unit , as it were) but this does not, despite his claims and despite, perhaps, first appearances, translate into an explanation for what he accepts is the historical fact that Mendeleev s periodic law attracted little attention before 1874—that is, before the initial success of the predictions. What his account would lead us to expect is, on the contrary, a high rate of credit for, and interest in, Mendeleev s scheme before 1874 and a somewhat higher rate afterwards. 

This volume of Topics in Stereochemistry could not be complete without hearing about ferroelectric liquid crystals, where chirality is the essential element behind the wide interest in this mesogenic state. In Chapter 8, Walba, a pioneering contributor to this area, provides a historical overview of the earlier key developments in this field and leads us to the discovery of the unique banana phases. This discussion is followed by a view of the most recent results, which involve, among others, the directed design of chiral ferroelectric banana phases, which display spontaneous polar symmetry breaking in a smectic liquid crystal. 

The historical use of the biologically based sensors mentioned above might lead us to the conclusion that finding hidden sources of explosives simply means training some kind of animal. Indeed, that conclusion has merit, and a great deal of success has been recorded in that way. This is discussed somewhat more fully in Chapter 8. There are, of course, disadvantages to this technique. The... 

Historical accounts of military conflicts since the First World War lead us to believe that the use of chemical weapons was non-existent for legal or ethical reasons, or for fear of retaliation. Matthew Meselson, a noted biochemist, stated, There have been only two instances of verified poison gas warfare since 1925. .. in Ethiopia and Yemen. 5 However, a preponderance of evidence exists to indicate that there have been numerous instances of chemical warfare use in military conflicts since 1918. In 1919, in India, stocks of phosgene and mustard gas were sent out from Britain for use on the frontier, and the Royal Air Force (RAF) is alleged to have used gas bombs against the Afghans in 1920. By 1925 the French and Spanish were employing poison gas in Morocco, and it had become clear that chemical warfare had found a new role, as a tool by which major powers could police rebellious territories. 

In the case of lead arsenate (acid form), calcium arsenate, and sodium arsenate, the Pb-isotopic compositions closely match those of sulfides from porphyry copper deposits from southeastern Arizona, specifically from the Pima and Silver Bell districts (Bouse et al., 1999). Notably, other major historical producers of arsenic trioxide (e.g., Anaconda Copper Co., US Smelting Co., Jardine Mining Co.) used... 

The content of the experience has an emotional richness that is profoundly deep, yet so positive that one must laugh aloud. Inevitably, the subjective richness, and the apparent self-coherence of the content of the tryptamine trance, leads those who experience it to wonder after its implications for modem humans. The idea of the simultaneous coexistence of an alien dimension all around us is as strange an idea in the context of modem society as it must have been to the first shamans, whose experiments with psychoactive plants would have soon brought them to the same tryptamine doorway. What is the nature of the invisible landscape beyond that doorway The answer to the question is linked to the question of the nature of mind. If the world beyond the doorway can be given consensual validation of the sort extended to the electron and the black hole—in other words, if the world beyond the doorway is found to be a necessary part of scientifically mature thinking about the world—then our own circumscribed historical stmggle will be subject to whole new worlds of possibility. 

Commercial evidence also supports the case for natural products. Of the 20 best-selling non-protein drags in 1999, nine were either derived from or developed as the result of leads generated by natural products (e.g., simvastatin, lovastatin, ciprofloxacin, clarithromycin and cyclosprin) with combined annual sales of greater than US 16 billion. Newer developments based on natural products include the antimalarial drag artemisinin, and the anticancer agents taxol, docetaxel and camptothecin. In addition to the historical success in dixig discoveiy, natural products are likely to continue to be sources of new commercially viable... 

It was not, however, until Jantzen [13] and his pupils had systematically investigated the physical fundamentals of the distillation process that the numerous developments after 1920 could take place. This later phase is stUl too recent to allow us to consider it historically. Ever and again we find, however, that multiple threads lead us back from our present complicated apparatus and methods to long-vanished times when the fundamental principles of our modern knowledge were first recognized and elaborated [14]. 

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