Linear kinetic Sunyaev-Zel'dovich effect and void models for acceleration

There has been considerable recent interest in cosmological models in which the current apparent acceleration is due to a very large local underdensity, or void, instead of some form of dark energy. Here we examine a new proposal to constrain such models using the linear kinetic Sunyaev-Zel'dovich (kSZ) effect due to structure within the void. The simplified "Hubble bubble" models previously studied appeared to predict far more kSZ power than is actually observed, independently of the details of the initial conditions and evolution of perturbations in such models. We show that the constraining power of the kSZ effect is considerably weakened (though still impressive) under a fully relativistic treatment of the problem, and point out several theoretical ambiguities and observational shortcomings which further qualify the results. Nevertheless, we conclude that a very large class of void models is ruled out by the combination of kSZ and other methods.Comment: 15 pages, 9 figures; minor changes, version published in CQG focus section "Inhomogeneous Cosmological Models and Averaging in Cosmology

Cloning and expression of the genes encoding the chick muscle nicotinic acetylcholine receptor

Imperial Users onl

The stability of thin shells

Imperial Users onl

Intrasite Feature Analysis of the Crescent Bay Hunt Club Site

The Crescent Bay Hunt Club Site (47JE904) is a Developmental Oneota site located on Lake Koshkonong in southeast Wisconsin. This site was occupied circa A.D. 1200 to 1400. Feature remains representing two wigwam style structures and at least one post in trench longhouse structure have been excavated at the site. Using 20 calibrated radio carbon dates ranging from A.D. 1000 to 1500, a Geographic Information System (GIS) is employed to conduct an analysis of the two structure types. It is concluded that despite the range of dates, there is no reason to believe a diachronic pattern is exhibited

Tools for Analysis of Complex Geometries for a Combined Cycle SCRAM Jet / Rocket

A preliminary design for a variable geometry combined cycle supersonic combustion ram jet (SCRAM jet) / rocket was developed. A precise geometry was selected by parametric analysis and the resultant geometry was analyzed using a computational fluid dynamics (CFD) code developed by Dr. Eric Perrell, and modified by, among others, the author. This paper is broken into several sections discussing, separately, the design innovations used to permit the geometry of the craft to be adjusted to conform to its flight conditions, the 2D analysis tool developed for the parametric analysis, development of the grid for CFD analysis, and modifications made to the CFD code to accommodate the complex geometries that necessarily were incorporated in the grid. Results are discussed at the end

Tilted Physics: A Cosmologically Dipole-Modulated Sky

Physical constants and cosmological parameters could vary with position. On the largest scales such variations would manifest themselves as gradients across our Hubble volume, leading to dipole-modulation of the cosmic microwave anisotropies. This generically leads to a correlation between adjacent multipoles in the spherical harmonics expansion of the sky, a distinctive signal which should be searched for in future data sets.Comment: 4 pages, 3 figure