Natural disasters and indicators of social cohesion

Do adversarial environmental conditions create social cohesion? We provide new answers to this question by exploiting spatial and temporal variation in exposure to earthquakes across Chile. Using a variety of methods and controlling for a number of socio-economic variables, we find that exposure to earthquakes has a positive effect on several indicators of social cohesion. Social cohesion increases after a big earthquake and slowly erodes in periods where environmental conditions are less adverse. Our results contribute to the current debate on whether and how environmental conditions shape formal and informal institutions

Neutron Stars and Black Holes in X-ray Binaries

Galactic accretion driven stellar X-ray sources can be divided into groups in different ways. An important division, which covers almost all known X-ray binaries, can be made according to the mass of the donor star: high-mass X-ray binaries and low-mass X-ray binaries. Another distinction (partially overlapping with the previous one) can be made on the basis of the nature of the accreting object: a strongly magnetized neutron star, a neutron star with a weak magnetic field, or a black hole. In this review I describe the properties of these different types of X-ray binaries, and discuss the mass determinations which are the basis for distinguishing accreting neutron stars from black holes.Comment: 58 pages, 15 figures. To be published in 'The Many Faces of Neutron Stars', R. Buccheri, J. van Paradijs, M.A. Alpar (Eds), Kluwer Academic Publisher