Why do firm growth and exit rates decline with size? What determines the size distribution of firms? This paper presents a theory of firm dynamics that simultaneously rationalizes the basic facts on firm growth, exit, and size distributions. The theory emphasizes the accumulation of industry specific human capital in response to industry specific productivity shocks. The theory implies that firm growth and exit rates should decline faster with size, and the size distribution should have thinner tails, in sectors that use human capital less intensively, or correspondingly, physical capital more intensively. In line with the theory, we document substantial sectoral heterogeneity in US firm dynamics and firm size distributions, which is well explained by variation in physical capital intensities.

Classic period Maya rulers are often reduced to "ideal types" and are discussed in terms that would suggest they were a homogenous group of individuals cut from the same cloth. Contrary to that assumption, this study employs epigraphic, iconographic, archaeological, ethnohistoric and ethnographic data to demonstrate there was significant local and regional variation in the way kingship was expressed through artistic programs, calendrics, ritual activity, accoutrements of power, sacred warfare, the taking of theophoric throne names and titulary, and the composition and adaptation of local pantheons.

The identity of each polity was inseparably connected with that of its ruler, and variations on the rulership theme served to reinforce their unique identity in the larger landscape vis-à-vis other polities. The underlying theoretical approach relies on concepts of mimesis and alterity, duality, and complementary opposition, all of which are creative acts which serve to establish a sense of Self in contrast to the Other, both human and divine. This study also examines concepts of divine kingship and deification, and argues that rulers were "functionally divine" while living and were elevated to "ontologically divine" status upon becoming apotheosized ancestors after death. As apotheosized ancestors, they took their place in the pliable local pantheon which further reinforced the unique identity of each site.