Fundamental data on the desorption of pure interstellar ices

The desorption of molecular ices from grain surfaces is important in a number of astrophysical environments including dense molecular clouds, cometary nuclei and the surfaces and atmospheres of some planets. With this in mind, we have performed a detailed investigation of the desorption of pure water, pure methanol and pure ammonia ices from a model dust-grain surface. We have used these results to determine the desorption energy, order of desorption and the pre-exponential factor for the desorption of these molecular ices from our model surface. We find good agreement between our desorption energies and those determined previously; however, our values for the desorption orders, and hence also the pre-exponential factors, are different to those reported previously. The kinetic parameters derived from our data have been used to model desorption on time-scales relevant to astrophysical processes and to calculate molecular residence times, given in terms of population half-life as a function of temperature. These results show the importance of laboratory data for the understanding of astronomical situations whereby icy mantles are warmed by nearby stars and by other dynamical events

The Precessing Top

I discuss the precession motion of a symmetrical top without the assumption that its precessional velocity is much smaller than its spin angular velocity. I derive the general formula for the precessional velocity in an elementary way and discuss the cases of slow and fast precessions.Comment: latex, 2 pages, 2 figure

Climate Change Policy in Canada and Germany: A Comparative Analysis

Climate change is an important issue. This paper will look at the climate change policy of Canada and Germany. In particular borrowing from Hessing et al.'s analysis of resource and environment policy by way of looking at the dynamics of policy networks, I will compare the climate change policy of Canada and Germany. Policy network analysis looks at the intersections of state and societal actors, and helps us to understand why we might see significant policy change and progression on the one hand or no change and only incremental progress on the other. Canada has gained a reputation for being a laggard when it comes to its national climate policy, whereas Germany has been praised for its more progressive approach and ambitious commitments to climate change policy. Using a framework inspired by Dr. Mark Winfield, in combination with policy network analysis, this paper will analyze Canada and Germany’s climate policy through an analysis of their institutional frameworks, political economic context, societal forces, and the ideas and discourses around the matter. The aim of this paper is to provide an analysis of the key problem areas for Canada’s climate change policy, through a comparison of Germany’s more progressive action on climate policy. In chapter one I will introduce the importance of climate change policy. In chapter two I provide an explanation of the significance of climate change and the science behind it. In chapter three I look at climate policy in Canada through an intuitional, political economic, societal and ideational framework in the context of policy networks and argue that jurisdictional ambiguity and the strong relationships between the state and economic interests have placed a significant barrier on moving forward on climate change. In chapter four, I apply this same framework to the German context and argue that the close ties between non-economic actors such as environmental groups and state officials, along with the overall general agreement within the climate policy community that action on climate change is required, has helped to foster a progressive climate change policy in the country. In chapter five I tie my arguments for each country together to highlight the key differences in the interactions of institutions, economic interests, societal actors, and the general ideas about climate chang