Ricerc@Sapienza

The association between city size and productivity has been widely investigated in the academic literature. On the contrary, less is known about the link between city size and material living conditions. Recently, a strong emphasis has been put on the process of urbanization without growth and on the burst of large cities. The creation of slums and large areas with underdeveloped housing characteristics has become a major concern for urban planners. This is especially the case for developing economies.

This article investigates the incidence of agglomeration
externalities in Ecuador, a small‐sized, middle‐income
developing country. In particular, we analyze the role of
the informal sector within these relations, since informal
employment accounts for a significant part of total employment
in the developing countries. Using individual level data
and instrumental variable techniques, we investigate the
impact of spatial externalities, in terms of population density,
local specialization and urban size, on the wages of workers

Neotropical cichlids include hundreds of species whose taxonomy has benefited of molecular phylogeny and whose karyotype evolution has been related to the amount and distribution of different classes of repetitive sequences. This study provides the first integrative molecular (cytochrome c oxidase subunit 1 and 16S sequences) and cytogenetic analyses of wild samples of the green terror Andinoacara rivulatus, a cichlid naturally distributed in Ecuador and spread throughout the world as an aquarium pet.