The Vlasov-Poisson system with radiation damping

We set up and analyze a model of radiation damping within the framework of continuum mechanics, inspired by a model of post-Newtonian hydrodynamics due to Blanchet, Damour and Schaefer. In order to simplify the problem as much as possible we replace the gravitational field by the electromagnetic field and the fluid by kinetic theory. We prove that the resulting system has a well-posed Cauchy problem globally in time for general initial data and in all solutions the fields decay to zero at late times. In particular, this means that the model is free from the runaway solutions which frequently occur in descriptions of radiation reaction

Anisotropic flow in the forward directions at sqrt(s_NN) = 200 GeV

The addition of the two Forward TPCs to the STAR detector allows one to measure anisotropic flow at forward pseudorapidities. This made possible the first measurement of directed flow at collision energies of sqrt(s_NN) = 200 GeV. PHOBOS' results on elliptic flow at forward rapidities were confirmed, and the sign of v2 was determined to be positive for the first time at RHIC energies. The higher harmonic, v4, is consistent with the recently suggested v2^2 scaling behavior.Comment: 4 pages, 5 figures; write-up of a poster (see http://cern.ch/Oldenburg/Talks/QM2004_Flow_Poster.pdf) presented at Quark Matter 2004, Oakland; reference 10 correcte

Photochemical Approaches to Complex Chemotypes: Applications in Natural Product Synthesis.

The use of photochemical transformations is a powerful strategy that allows for the formation of a high degree of molecular complexity from relatively simple building blocks in a single step. A central feature of all light-promoted transformations is the involvement of electronically excited states, generated upon absorption of photons. This produces transient reactive intermediates and significantly alters the reactivity of a chemical compound. The input of energy provided by light thus offers a means to produce strained and unique target compounds that cannot be assembled using thermal protocols. This review aims at highlighting photochemical transformations as a tool for rapidly accessing structurally and stereochemically diverse scaffolds. Synthetic designs based on photochemical transformations have the potential to afford complex polycyclic carbon skeletons with impressive efficiency, which are of high value in total synthesis.R01 GM073855 - NIGMS NIH HHS; R01 GM096129 - NIGMS NIH HHS; R35 GM118173 - NIGMS NIH HH

Evaluation of different sources of uncertainty in climate change impact research using a hydro-climatic model ensemble

The international research project QBic3 (Quebec-Bavarian Collaboration on Climate Change) aims at investigating the potential impacts of climate change on the hydrology of regional scale catchments in Southern Quebec (Canada) and Bavaria (Germany). Yet, the actual change in river runoff characteristics during the next 70 years is highly uncertain due to a multitude of uncertainty sources. The so-called hydro-climatic ensemble that is constructed to describe the uncertainties of this complex model chain consists of four different global climate models, downscaled by three different regional climate models, an exchangeable bias correction algorithm, a separate method to scale RCM outputs to the hydrological model scale and several hydrological models of differing complexity to assess the impact of different hydro model concepts. This choice of models and scenarios allows for the inter-comparison of the uncertainty ranges of climate and hydrological models, of the natural variability of the climate system as well as of the impact of scaling and correction of climate data on mean, high and low flow conditions. A methodology to display the relative importance of each source of uncertainty is proposed and results for past runoff and potential future changes are presented