Henderson process

Figure 12. An example of use of to assess the rate and depth of sediment mixing from a core on the slopes of the Bahamas (Henderson et al. 1999b). The exponential decrease in Pbxs seen in the upper 6 cm of the sediment reflects decay of °Pb as it is mixed downward. The diffusional model of mixing described in the text indicates a mixing rate, D, of 51 cm kyr for this core. The two circled points at greater depth reflect rapid injection of surface material to depth in a process known as conveyor-belt feeding (Robbins 1988 Smith et al. 1997).

As discussed elsewhere in this volume, another field where the use of U-series disequilibria has proven to be very useful is the study of chemical transport in waters, either marine (see Cochran and Masque 2003 Henderson and Anderson 2003), estuarine (Swarzenski et al. 2003) or continental waters. In the continental domain, in addition to characterization of transfer processes related to groundwater flows (Porcelli and Swarzenski 2003), radioactive disequilibria have also helped in constraining chemical exchanges between particulate, dissolved and colloidal loads of waters, as well as the origin of chemical fluxes carried by waters. 

Henderson A wet process for extracting copper from its ores. Operated in Widnes in 1860. 

Longmaid-Henderson A process for recovering copper from the residue from the roasting of pyrites to produce sulfur dioxide for the manufacture of sulfuric acid. The residue was roasted with sodium chloride at 500 to 600°C the evolved sulfur oxides and hydrochloric acid were scrubbed in water and the resulting solution was used to leach the copper from the solid residue. Copper was recovered from the leachate by adding scrap iron. The process became obsolete with the general adoption of elemental sulfur as the feedstock for sulfuric acid manufacture. 

Pistiner J, Henderson GM (2003) Lithium isotope fractionation during continental weathering processes. Earth Planet Sci Lett 214 327-339... 

One reason is that firms who want to employ the new technology cannot merely invest in basic research. Cockburn and Henderson (1998) emphasize that it is also important for the firm to be actively connected to the wider scientific community (p. 158). They developed the concept of connectedness, as measured by the extent of collaboration in writing scientific papers across institutional boundaries, and conclude that firms wishing to public sector research must do more than simply invest in in-house basic research they must also actively collaborate with their public sector colleagues. The extent of this collaboration... is positively related to private sector research productivity (p. 180). The process by which firms acquire this new technology is not simple or direct, nor obtained without cost. 

Research spending in the pharmaceutical industry is carried out in the context of considerable interfirm rivalry. 1 emphasized that point in my first article on this topic (Comanor 1964) but provided no formal model of the process. Since that time, there have been more formal discussions of these issues. A particularly lucid one is offered by Cockburn and Henderson (1994), which emphasizes the competitive nature of the drug discovery process. 

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