The culture history of Madagascar

Madagascar's culture is a unique fusion of elements drawn from the western, northern, and eastern shores of the Indian Ocean, and its past has fascinated many scholars, yet systematic archaeological research is relatively recent on the island. The oldest traces of visitors are from the first century AD. Coastal settlements, with clear evidence of ties to the western Indian Ocean trading network, were established in several places over the next millennium. Important environmental changes of both plant and animal communities are documented over this period, including the extinctions of almost all large animal species. Urban life in Madagascar began with the establishment of the entrepôt of Mahilaka on the northwest coast of the island in the twelfth century. At about the same time, communities with ties to the trade network were established around the island's coasts. From the fourteenth to the sixteenth century, social hierarchies developed in several regions of the island. During the succeeding two centuries, Madagascar saw the development of state polities.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/45256/1/10963_2004_Article_BF00997802.pd

Influence of the undoped a Si H buffer layer on a Si H c Si heterojunctions from planar conductance and lifetime measurements

International audienceIn highly efficient amorphous silicon/crystalline silicon heterojunction (a-Si:H/c-Si) solar cells, the c-Si wafer is passivated by a nanometer-thin buffer layer, which is undoped amorphous silicon. Here, we report on the systematic measurement of the passivation quality (minority carrier effective lifetime) by photo-conductance decay and of the band bending in c-Si using the planar conductance technique. The thickness of the buffer layers is varied. An analytical model to calculate the band bending in c-Si is presented; it aids in understanding the influence of the buffer layer on the band bending. We find that when the buffer layer thickness increases the passivation quality increases and the band bending decreases. Therefore, we suggest that an optimum has to be found to reach good interface defect passivation and a high band bending