Theoretical and Experimental Study of Improved Catastrophic Optical Damage Performance in 830nm High Power Lasesr with Non-absorbing Mirrors

We carry out a systematic theoretical and experimental study on the improvement in catastrophic optical damage of 830 nm lasers with non-absorbing mirrors. We find a three-fold increase in COD optical power level compared to conventional lasers

OMEGA: a short-wavelength laser for fusion experiments

The OMEGA, Nd:glass laser facility was constructed for the purpose of investigating the feasibility of direct-drive laser fusion. With 24 beams producing a total energy of 4 kJ or a peak power of 12 TW, OMEGA is capable of nearly uniform illumination of spherical targets. Six of the OMEGA beams have recently been converted to short-wavelength operation (351 nm). In this paper, we discuss details of the system design and performance, with particular emphasis on the frequency-conversion system and multi-wavelength diagnostic system

Biogeography of terrestrial and freshwater vertebrates from the late Cretaceous (Campanian) Western Interior of North America

Previous biogeographic studies of late Cretaceous (late Campanian) vertebrate faunas in the Western Interior Basin (WIB) of North America have suggested the presence of faunal and floral provincialism, characterized by distinct northern and southern 'biomes.' However, the "provincialism hypothesis" has been questioned based largely on the contention that the investigated faunas were recovered from a series of diachronous, time-transgressive deposits, and are therefore non-correlative.\ud \ud Extensive work in several fossiliferous units of late Campanian age, including the Dinosaur Park, Judith River, Two Medicine, Kaiparowits, Fruitland/Kirtland, and Aguja formations, has greatly increased understanding of WIB vertebrate faunas and their chronostratigraphic relationships. Here updated and greatly expanded faunal and chronostratigraphic datasets are utilized to undertake an extensive biogeographic analysis of these six terrestrial fossiliferous formations within the WIB of North America. Quantitative biogeographic comparisons of the formations and their constituent faunas are conducted using four statistical methods: Analysis of Similarity, Q-mode cluster analysis, Parsimony Analysis of Endemicity, and Correspondence Analysis.\ud \ud The results of this study provide strong support for highly divergent faunas in northern and southern regions of the WIB, with a latitudinal faunal gradient as an interface. Yet the nature of the interface between these faunas remains unclear, with possibilities including: 1) two or more discrete provinces separated by a zone (or zones) of faunal mixing; and 2) a continuous latitudinal gradient or cline, with no discrete zones of endemism. Lacking evidence of any physiographic barrier to north–south dispersal, climatic variation within the WIB is regarded as the most likely explanation for the overarching biogeographic patterns observed for late Campanian vertebrate taxa

Biogeography of terrestrial and freshwater vertebrates from the late Cretaceous (Campanian) Western Interior of North America

Previous biogeographic studies of late Cretaceous (late Campanian) vertebrate faunas in the Western Interior Basin (WIB) of North America have suggested the presence of faunal and floral provincialism, characterized by distinct northern and southern 'biomes.' However, the "provincialism hypothesis" has been questioned based largely on the contention that the investigated faunas were recovered from a series of diachronous, time-transgressive deposits, and are therefore non-correlative.\ud \ud Extensive work in several fossiliferous units of late Campanian age, including the Dinosaur Park, Judith River, Two Medicine, Kaiparowits, Fruitland/Kirtland, and Aguja formations, has greatly increased understanding of WIB vertebrate faunas and their chronostratigraphic relationships. Here updated and greatly expanded faunal and chronostratigraphic datasets are utilized to undertake an extensive biogeographic analysis of these six terrestrial fossiliferous formations within the WIB of North America. Quantitative biogeographic comparisons of the formations and their constituent faunas are conducted using four statistical methods: Analysis of Similarity, Q-mode cluster analysis, Parsimony Analysis of Endemicity, and Correspondence Analysis.\ud \ud The results of this study provide strong support for highly divergent faunas in northern and southern regions of the WIB, with a latitudinal faunal gradient as an interface. Yet the nature of the interface between these faunas remains unclear, with possibilities including: 1) two or more discrete provinces separated by a zone (or zones) of faunal mixing; and 2) a continuous latitudinal gradient or cline, with no discrete zones of endemism. Lacking evidence of any physiographic barrier to north–south dispersal, climatic variation within the WIB is regarded as the most likely explanation for the overarching biogeographic patterns observed for late Campanian vertebrate taxa

The Norton dome and the nineteenth century foundations of determinism

The recent discovery of an indeterministic system in classical mechanics, the Norton dome, has shown that answering the question whether classical mechanics is deterministic can be a complicated matter. In this paper I show that indeterministic systems similar to the Norton dome were already known in the nineteenth century: I discuss four nineteenth century authors who wrote about such systems, namely Poisson, Duhamel, Boussinesq and Bertrand. However, I argue that their discussion of such systems was very different from the contemporary discussion about the Norton dome, because physicists in the nineteenth century conceived of determinism in essentially different ways: whereas in the contemporary literature on determinism in classical physics, determinism is usually taken to be a property of the equations of physics, in the nineteenth century determinism was primarily taken to be a presupposition of theories in physics, and as such it was not necessarily affected by the possible existence of systems such as the Norton dome