Exploring the Niche Overlaps Between Organizational Ecology and Industrial Economics

The goal of this essay is to bring the work of organizationalecologists on population dynamics to the attention of economistsand to try to engineer an exchange of ideas between the twosubjects. Following a relatively brief exposition of the basicarguments made by organizational ecologists, we explore a numberof areas where cross-fertilization between organizational ecologyand industrial economics seems promising. These include: examiningthe limits of competitive exclusion; exploring how models thatfocus on selection between firms might apply to selection betweenproducts; linking models of population dynamics to models whichexplain changes in market structures over time; understandingthe sources of structural inertia which limit the ability offirms to react to market events. We conclude by making a fewobservations on what each group of scholars might learn fromthe other.     

Swelling in the isolated perfused cornea induced by 12(R)hydroxyeicosatetraenoic acid

PURPOSE: To evaluate the effect of 12(R)hydroxyeicosatetraenoic acid (12(R)HETE) on corneal swelling when directly perfused to human and rabbit corneal endothelium. METHOD: Excised rabbit and human corneas were mounted in the in vitro specular microscope and the endothelium was perfused with 12(R)HETE at 10(-5), 10(-6), and 10(-7) mol/l. Both 12(R)HETE and 12(S)HETE were compared at equal molar (10(-6) mol/l) concentrations. The reversal of 12(R)HETE and ouabain corneal swelling was also compared. Endothelial permeability to carboxyfluorescein was measured after 12(R)HETE perfusion. High-performance liquid chromatographic analysis confirmed that 12(R)HETE remained in the perfusion media. RESULTS: 12(R)HETE caused a dose-dependent corneal swelling of 25 +/- 2, 24 +/- 1, and 14 +/- 0.5 microns/hr at 10(-5), 10(-6), and 10(-7) mol/l, respectively. Equal molar concentrations (10(-6) mol/l) of 12(S)HETE did not cause corneal swelling. Removal of the 12(R)HETE from the perfusion media resulted in reversal of corneal swelling whereas corneal swelling induced by ouabain did not reverse after ouabain removal. 12(R)HETE (10(-6) mol/l) perfused to the human corneal endothelium inhibited temperature reversal corneal thinning when compared to the paired corneal endothelium perfused with BSS Plus (Alcon Laboratories, Inc., Fort Worth, TX). Na/K adenosine triphosphatase activity was inhibited by 10(-6) mol/l ouabain by 35%, 10(-6) mol/l 12(R)HETE by 54%, and 10(-6) mol/l 12(S)HETE by 0.5%. Endothelial permeability to carboxyfluorescein was unaffected by 12(R)HETE. CONCLUSION: 12(R)HETE causes corneal swelling by inhibiting endothelial pump function. This inhibition of transport appears to be at least partly mediated by inhibition of endothelial Na/K adenosine triphosphatase.     

Learning and the sources of corporate growth

This paper explores the link between learning and corporategrowth by developing different models of learning and showingthat they produce observably different models of corporate growth.Using data on the growth of a number of firms in the US automobileindustry during the 20th century, we compare these differentmodels of growth in an effort to identify the major sourcesof learning which these firms seem to have relied on. Althoughthere are interesting differences between growth processes beforeand after the Second World War, the basic conclusion that weare drawn to is that learning in this sector is largely unsystematicand opportunistic.