Global modelling revisited

Reasons for the great impact of World Dynamics and Limits to Growth include their addressing the correct audience (the public), and the ability of systems dynamics clearly to handle and communicate information on complex and often little understood areas. Modelling projects should usually be global or national (not regional), draw heavily on mental and not just written and numerical databases, and have time horizons of perhaps 100 years. Sadly, critics of Worlds 2 and 3 have yet to come to grips with the fundamental messages presented there, although these messages are becoming increasingly vital.     

Images in pathology: Alzheimer's disease

The review describes the histopathology and pathophysiology of Alzheimer's disease.     

Investitionsvolumen und Herausforderungen eines nationalen Glasfaserausbaus in Deutschland

Der fl?chendeckende Glasfaserausbau in Deutschland ist mit hohen Kosten verbunden. Insbesondere die Anschlüsse in dünn besiedelten Gebieten lassen die Kosten steigen. Die Autoren berechnen verschiedene M?glichkeiten der Kostenaufteilung.     

再见,祝你好运,下周见

这是公司发展史上策划最周详的过渡之一.两年前,微软公司董事长比尔·盖茨宣布,他将放手在这家他与别人共同创建的公司的日常管理责任,把更多的时间投入慈善事业.从那以后,盖茨和微软公司首席执行官史蒂芬·巴尔默提拔了那些将会接替盖茨,为微软公司开发技术、战略和远景的人.     

Implications of Economic Interdependence for Endogenous Wage Indexation Decisions

This paper shows how economic interdependence affects the indexation decisions of atomistic wage setters in an environment in which monetary authorities do not observe stochastic disturbances before making their policy choices. If stochastic disturbances are common across countries, interdependence has no effect on equilibrium indexation choices in identical countries. However, if disturbances are country specific, numerical simulations show that interdependence is likely to reduce equilibrium indexation choices relative to a small open economy. We also show that indexation choices may be either strategic complements or strategic substitutes, but that strategic complementarity becomes more likely as the degree of interdependence rises.     

Adverse Selection and Pay Compression

A fundamental result of the principal-agent literature is that pay will be linked to performance when it is difficult for the principal to monitor the agent's actions. However, performance pay can lead to adverse incentives. In these models, high-powered incentives encourage workers to neglect some aspects of their job or to sabotage their coworkers' efforts. This paper offers another explanation for the weak link between pay and performance: worker heterogeneity. When workers are heterogeneous and labor contracts are contests, the Nash equilibrium often pools workers. I show that this implies that the link between pay and performance is weaker than would be the case if firms could observe workers' types before contracting and offer each type their respective optimal contests.     

Cow-calf profitability and leptin genotyping

Profitability of cow-calf production is determined largely by market prices, calf weaning weights, and cow productive life. While producers individually have no effect on prices, weaning weights and productive life have genetic influences and hence can be altered by selection programs implemented by producers. We investigate the impact of a mutation in the leptin gene (exon 2; single nucleotide polymorphism [SNP] 305) on cow-calf profitability. Prior research shows that this mutation has effects on performance and traits of fed cattle and milk production in dairy cows. Using data from a teaching-research herd, we find that it is also associated with calf weaning weights and cow productive life. A bio-economic stochastic simulation demonstrates that the mutation has statistically positive impacts on profits, suggesting that producers can profitably make use of this information.