The occurrence of oscillatory behaviours in living cells can be viewed as a visible consequence of stable, regulatory homeostatic cycles. Therefore, they may be used as experimental windows on the underlying physiological mechanisms. Recent studies show that growing pollen tubes are an excellent biological model for these purposes. They unite experimental simplicity with clear oscillatory patterns of both structural and temporal features, most being measurable during real‐time in live cells. There is evidence that these cellular oscillators involve an integrated input (...) of plasma membrane ion fluxes, and a cytosolic choreography of protons, calcium and, most likely, potassium and chloride. In turn, these can create positive feedback regulation loops that are able to generate and self‐sustain a number of spatial and temporal patterns. Other features, including cell wall assembly and rheology, turgor, and the cytoskeleton, play important roles and are targets or modulators of ion dynamics. Many of these features have similarities with other cell types, notably with apical‐growing cells. Pollen tubes may thus serve as a powerful model for exploring the basis of cell growth and morphogenesis. BioEssays 23:86–94, 2001. © 2001 John Wiley & Sons, Inc. (shrink)

É reconhecida, contemporaneamente, a capacidade da literatura na formação de sujeitos críticos e participantes socialmente. Sendo assim, tão logo a escola passou a ser popularizada, a literatura teve, também, ampla divulgação nesse espaço. No entanto, apesar dessa relação ter sido iniciada por volta de cinquenta anos, cada vez mais, constata-se a dificuldade da escola na formação de leitores literários. Em vista disso , é objetivo deste artigo problematizar questões pertinentes ao trabalho com a literatura em dois espaços fundamentais para melhorar (...) a qualidade da educação básica no Brasil : a sala de aula e a biblioteca. (shrink)