Since cosmological black holes modify the density and pressure of the surrounding universe, and introduce heat conduction, they produce simple models of cosmologi-cal inhomogeneities that can be used to study the eect of inhomogeneities on the universe's expansion. In this thesis, new cosmological black hole solutions are ob-tained by generalizing the expanding Kerr-Schild cosmological black holes to obtain the charged case, by performing a Kerr-Schild transformation of the Einstein-de Sitter universe (instead of a closed universe) to obtain non-expanding Kerr-Schild cosmo-logical black holes in asymptotically- at universes, and by performing a conformal transformation on isotropic black hole spacetimes to obtain isotropic cosmological black hole spacetimes. The latter approach is found to produce cosmological black holes with energy-momentum tensors that are physical throughout spacetime, unlike previous solutions for cosmological black holes, which violate the energy conditions in some region of spacetime. In addition, it is demonstrated that radiation-dominated and matter-dominated Einstein-de Sitter universes can be directly matched across a hypersurface of constant time, and this is used to generate the rst solutions for primordial black holes that evolve from being in radiation-dominated background universes to matter-dominated background universes. Finally, the Weyl curvature, volume expansion, velocity eld, shear, and acceleration are calculated for the cos-ii mological black holes. Since the non-isotropic black holes introduce shear, according to Raychaudhuri's equation they will tend to decrease the volume expansion of the universe. Unlike several studies that have suggested the relativistic backreaction of inhomogeneities would lead to an accelerating expansion of the universe, it is con-cluded that shear should be the most likely in uence of inhomogeneities, so they should most likely decrease the universe's expansion. iii

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This report focuses on the evidence about the health.consequences of smoking for women, and is intended to serve.the public health and medical communities as 'a unified source of existing scientific research. The major issues about tobacco use and women's health are examined, including trends in consumption, biomedical evidence, and determinants of smoking ititiation, maintenance, and cessation. The biomedical aspects ofsmoking are presented in terms of mortality, morbiplity, cardiovasculaidiseases, cancer, pregnancy and infant,health,, Teptic ulcer disease, drug reactions and, interactions, food constituents, and responses to,diagnostic tests. The psychosocial and behavioraj. aspects, of smoking in women are discussed, along with the docffiented increases in- the risk of contracting lung cancer, heart,disease, or lung disease. The harmful effects of pregnant mothers smoking behaviors, are also docudented. Adhitionally, recent data are enumerated to indicate a trend of,decreasing tobacco usage among women in response to the warnings of the gavernMent, voluntary agencie, and physicrins. (Author /NRB)' DOCUMENT RESUME cc 015 465

Ultracold atoms in optical lattices provide a highly control-lable environment for the clean experimental realization of various model Hamiltonians from condensed matter and statistical physics. For example, the two-component Bose-Hubbard model, which re-duces to an anisotropic spin-1/2 Heisenberg

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In this thesis, two sets of experimental studies in bosonic and fermionic gases are described. In the first part of the thesis, itinerant ferromagnetism was studied in a strongly interacting Fermi gas of ultracold atoms. The observation of nonmonotonic behavior of lifetime, kinetic energy, and size for increasing repulsive interactions pro-vides strong evidence for a phase transition to a ferromagnetic state. Our observations imply that itinerant ferromagnetism of delocalized fermions is possible without lattice and band structure, and our data validate the most basic model for ferromagnetism introduced by Stoner. In the second part of the thesis, the coherence properties of a Bose-Einstein con-densate (BEC) was studied in a radio frequency induced double-well potential imple-mented on a microfabricated atom chip. We observed phase coherence between the separated condensates for times up to 200 ms after splitting, a factor of 10 longer than the phase diffusion time expected for a coherent state for our experimental con-ditions. The enhanced coherence time is attributed to number squeezing of the initial