A rigorous solution concept for geodesic and geodesic deviation equations in impulsive gravitational waves

The geodesic as well as the geodesic deviation equation for impulsive gravitational waves involve highly singular products of distributions (\theta\de, \theta^2\de, \de^2). A solution concept for these equations based on embedding the distributional metric into the Colombeau algebra of generalized functions is presented. Using a universal regularization procedure we prove existence and uniqueness results and calculate the distributional limits of these solutions explicitly. The obtained limits are regularization independent and display the physically expected behavior.Comment: RevTeX, 9 pages, final version (minor corrections, references added

The proton structure function F2 in the resonance region

Unique measurement of the proton structure function F2 in a wide two-dimensional region of x and Q**2 has been reported. The accessible kinematics covers entire resonance region up to W=2.5 GeV in the Q**2 interval from 0.1 to 4.5 GeV**2. Obtained data allowed for the first time an evaluation of moments of the structure function F2 directly from experimental data as well as an intensive study of the Bloom-Gilman duality phenomenon.Comment: 6 pages, 4 figures, Proceedings of GDH2002 Conference, 3-6 July 2002, Genova, Italy, to be published in World Scientifi

Recent results on the search for continuous sources with LIGO and GEO600

An overview of the searches for continuous gravitational wave signals in LIGO and GEO 600 performed on different recent science runs and results are presented. This includes both searching for gravitational waves from known pulsars as well as blind searches over a wide parameter space.Comment: TAUP2005 Proceedings to be published in Journal of Physics: Conference Serie

Convergence science in the Anthropocene: Navigating the known and unknown

Rapidly changing ecological and social systems currently pose significant societal challenges. Navigating the complexity of social-ecological change requires ap- proaches able to cope with, and potentially solve, both foreseen and unforeseen societal challenges. The emergent field of convergence addresses the intricacies of such challenges, and is thus relevant to a broad range of interdisciplinary issues. This paper suggests a way to conceptualize convergence research. It discusses how it relates to two major societal challenges (adaptation, transformation), and to the generation of policy-relevant science. It also points out limitations to the further development of convergence research