Suchergebnisse

Abstract. Coastal flooding is a problem of increasing relevance in low-lying coastal regions worldwide. In addition to the anticipated increase in likelihood and magnitude of coastal floods due to climate change, there is rapid growth in coastal assets and infrastructure. Sustainable and integrated coastal flood management over large areas and varying coastline types cannot be simply treated as local combinations of flood defences and floodplains. Rather, a system level analysis of floodplains is required to structure the problem as a first step before applying quantitative models. In this paper such a model is developed using system diagrams and the Source-Pathway-Receptor (SPR) concept, to structure our understanding of large and complex coastal flood systems. A graphical systems model is proposed for the assessment of coastal flood systems with regard to individual elements and their topological relationships. Two examples are discussed – a unidirectional model for a large-scale flood system, and a multi-directional model for a smaller-scale system, both based on the Western Scheldt estuary. The models help to develop a comprehensive understanding of system elements and their relationships and provide a holistic overview of the coastal flood system. The approach shows that a system level analysis of floodplains is more effective than simple topographic maps when conveying complex information. The models are shown to be useful as an apriori approach for making the assumptions about flood mechanisms explicit and for informing inputs to numerical models.

We present a search for gravitational waves from 116 known millisecond and young pulsars using data from the fifth science run of the LIGO detectors. For this search, ephemerides overlapping the run period were obtained for all pulsars using radio and X-ray observations. We demonstrate an updated search method that allows for small uncertainties in the pulsar phase parameters to be included in the search. We report no signal detection from any of the targets and therefore interpret our results as upper limits on the gravitational wave signal strength. The most interesting limits are those for young pulsars. We present updated limits on gravitational radiation from the Crab pulsar, where the measured limit is now a factor of 7 below the spin-down limit. This limits the power radiated via gravitational waves to be less than similar to 2% of the available spin-down power. For the X-ray pulsar J0537-6910 we reach the spin-down limit under the assumption that any gravitational wave signal from it stays phase locked to the X-ray pulses over timing glitches, and for pulsars J1913+1011 and J1952+3252 we are only a factor of a few above the spin-down limit. Of the recycled millisecond pulsars, several of themeasured upper limits are only about an order of magnitude above their spin-down limits. For these our best (lowest) upper limit on gravitational wave amplitude is 2.3 x 10(-26) for J1603-7202 and our best (lowest) limit on the inferred pulsar ellipticity is 7.0 x 10(-8) for J2124-3358. ; Australian Research Council ; Council of Scientific and Industrial Research of India ; Istituto Nazionale di Fisica Nucleare of Italy ; Spanish Ministerio de Educacion y Ciencia ; Conselleria d'Economia Hisenda i Innovacio of the Govern de les Illes Balears ; Netherlands Organisation for Scientific Research ; Royal Society ; Scottish Funding Council ; Polish Ministry of Science and Higher Education ; Foundation for Polish Science ; Scottish Universities Physics Alliance ; National Aeronautics and Space Administration ; Carnegie Trust ; Leverhulme Trust ; David and Lucile Packard Foundation ; Research Corporation ; Alfred P. Sloan Foundation ; Natural Sciences and Engineering Research Council of Canada ; Commonwealth Government ; Astronomy