Mundos em miniatura: aproximação a alguns aspectos da cartografia portuguesa do Brasil (séculos XVI a XVIII)

This paper discusses the challenges of "miniaturizing" the world in Portuguese cartography at the dawn of the Modern Age. It draws attention to the process of amassing experience and geographic knowledge, and their deployment in the cartographic representations of Brazil throughout the first three centuries of its colonization

A chemotaxis-based explanation of spheroid formation in 3D cultures of breast cancer cells

International audienceThree-dimensional cultures of cells are gaining popularity as an in vitro improvement over 2D Petri dishes. In many such experiments, cells have been found to organize in aggregates. We present new results of three-dimensional in vitro cultures of breast cancer cells exhibiting patterns. Understanding their formation is of particular interest in the context of cancer since metastases have been shown to be created by cells moving in clusters. In this paper, we propose that the main mechanism which leads to the emergence of patterns is chemotaxis, i.e., oriented movement of cells towards high concentration zones of a signal emitted by the cells themselves. Studying a Keller-Segel PDE system to model chemotactical auto-organization of cells, we prove that it is subject to Turing instability under a time-dependent condition. This result is illustrated by two-dimensional simulations of the model showing spheroidal patterns. They are qualitatively compared to the biological results and their variability is discussed both theoretically and numerically

Alexandre De Gusmão (1695-1753) e a tributação das minas do Brasil Alexandre de Gusmão (1695-1753) and the taxation of the mines of Brazil

O artigo tem por objetivo analisar a política tributária de Portugal para as regiões mineradoras do Brasil ao longo da primeira metade do século XVIII. Naquele período, o poder da Coroa se fez mais presente na América portuguesa. Tal crescimento pode ser explicado, por um lado, a partir da maior complexidade que a própria monarquia adquire ao longo da época moderna, e, por outro, em razão do desenvolvimento de novas atividades produtivas da colônia. No Brasil, o aspecto mais visível do crescimento da presença do Estado vincula-se à política tributária e fiscal e, nesse sentido, Alexandre de Gusmão teve um papel de destaque, propondo uma reforma tributária que substituía a multiplicidade de impostos existentes por uma "capitação".<br>The objective of this article is to analyze the tributary politics in Portugal in relation to Brazil along the first half of the XVIII century. In that period, the monarchy power was stronger in Portuguese America. Such growth can be explained, on one hand, starting from the largest complexity that the monarchy acquires along the modern time, and, on the other hand, because of the development of colony's productive activities. In Brazil, the most visible aspect related to the State's presence growth is linked to the tributary politics and, in which Alexandre de Gusmão had a distinctive role proposing a tax reformation that could substitute the multiplicity of existent taxes for a "capitation"