The Importance of Clusters for Sustainable Innovation Processes: The Context of Small and Medium Sized Regions

The purpose of the current paper is to provide a critical state-of-the-art review of current research on clusters and its correlation to innovation dynamics in small and medium-sized regions. In particular, we focus on the systematization of the main concepts and theoretical insights that are tributary to the cluster overview in terms of its relevance for the sustainability of the innovation processes, knowledge production and diffusion, which take place inside small and medium-sized regions. The present working paper takes into account the initial studies on English industrial districts (in the nineteenth century), passing through the Italian industrial districts (in the 70s and 80s of the twentieth century), until the modern theories of business clusters and innovation systems. These frameworks constitute the basis of an approach to endogenous development, which gives a central role to the interaction between economic actors, the society and the institutions and to the identification, mobilization and combination of potential resources within a particular geographical area.Cluster; Innovation; Endogenous development; Territory.

Effect of FSH on testicular morphology and spermatogenesis in gonadotrophin-deficient hypogonadal mice lacking androgen receptors

Follicle stimulating hormone (FSH) and androgen act to stimulate and maintain spermatogenesis. FSH acts directly on the Sertoli cells to stimulate germ cell number and acts indirectly to increase androgen production by the Leydig cells. In order to differentiate between the direct effects of FSH on spermatogenesis and those mediated indirectly through androgen action we have crossed hypogonadal (hpg) mice which lack gonadotrophins with mice lacking androgen receptors (AR) either ubiquitously (ARKO) or specifically on the Sertoli cells (SCARKO). These hpg.ARKO and hpg.SCARKO mice were treated with recombinant FSH for 7 days and testicular morphology and cell numbers assessed. In untreated hpg and hpg.SCARKO mice germ cell development was limited and did not progress beyond the pachytene stage. In hpg.ARKO mice testes were smaller with fewer Sertoli cells and germ cells compared to hpg mice. Treatment with FSH had no effect on Sertoli cell number but significantly increased germ cell numbers in all groups. In hpg mice FSH increased numbers of spermatogonia and spermatocytes and induced round spermatid formation. In hpg.SCARKO and hpg.ARKO mice, in contrast, only spermatogonial and spermatocyte numbers were increased with no formation of spermatids. Leydig cell numbers were increased by FSH in hpg and hpg.SCARKO mice but not in hpg.ARKO mice. Results show that in rodents 1) FSH acts to stimulate spermatogenesis through an increase in spermatogonial number and subsequent entry of these cells into meiosis, 2) FSH has no direct effect on the completion of meiosis and 3) FSH effects on Leydig cell number are mediated through interstitial ARs

ARES - Acervo de Recursos Educacionais em Saúde

O documento apresenta as principais informações de funcionamento e tratamento de informação do Acervo de Recursos Educacionais em Saúde - ARES, abordando aspectos como: suas tecnologias, direitos autorais e processo de entrada e recuperação de informação