Ages for exoplanet host stars

Age is an important characteristic of a planetary system, but also one that is difficult to determine. Assuming that the host star and the planets are formed at the same time, the challenge is to determine the stellar age. Asteroseismology provides precise age determination, but in many cases the required detailed pulsation observations are not available. Here we concentrate on other techniques, which may have broader applicability but also serious limitations. Further development of this area requires improvements in our understanding of the evolution of stars and their age-dependent characteristics, combined with observations that allow reliable calibration of the various techniques.Comment: To appear in "Handbook of Exoplanets", eds. Deeg, H.J. & Belmonte, J.A, Springer (2018

Overthrowing the dictator: a game-theoretic approach to revolutions and media

A distinctive feature of recent revolutions was the key role of social media (e.g. Facebook, Twitter and YouTube). In this paper, we study its role in mobilization. We assume that social media allow potential participants to observe the individual participation decisions of others, while traditional mass media allow potential participants to see only the total number of people who participated before them. We show that when individuals’ willingness to revolt is publicly known, then both sorts of media foster a successful revolution. However, when willingness to revolt is private information, only social media ensure that a revolt succeeds, with mass media multiple outcomes are possible, one of which has individuals not participating in the revolt. This suggests that social media enhance the likelihood that a revolution triumphs more than traditional mass media

Lebanon Can't Give Him a Future : Revolutionary Subjectivity and Syrian Rebel-Workers in Beirut

This chapter traces the Syrian crisis through the lives of Syrian labourers in Beirut. Lebanon has maintained a significant population of migrant workers for decades. Men undertook largely seasonal work with extended periods of wage labour abroad. However, there was little evidence of permanent settlement and few signs that a second-generation of Syrians settling permanently across the border. The chapter describes how and why — when the first rumbling of the uprising began to break — a number of migrant workers expressed support for what they called ‘the revolution’. From this, it moves to chart the overbearing harsh realities of the present, that is, realities of intense legal, economic and social precarity against which men hope only to survive