Inhomogeneous Broadening and the Kosterlitz-Thouless Transition

Journals published by the American Physical Society can be found at http://journals.aps.org/Torsional-oscillator studies of very thin He-4 films have found nonuniversal behavior of the superfluid response as a function of coverage. The temperature width of the superfluid transition region is nonmonotonic in the areal density n and exhibits cusplike variations at half of the layering period. We explore the assumption that this additional broadening is caused by macroscopic inhomogeneities in the substrate potential; such a theory for inhomogeneous broadening can be constructed from the Kosterlitz-Nelson relation between the superfluid areal density n(s) and the transition temperature T(c) by determining the theoretical ''sensitivity'' S of n(s) to variations in the strength of the substrate potential. For substrate models that are atomically uniform, a simple microscopic hypernetted-chain calculation (without either ''elementary diagrams'' or three-body correlations, but with an optimized Jastrow function) finds this sensitivity always to be of the same sign, and yields reasonable order-of-magnitude agreement with experiment. However, models for which the sensitivity does not change sign appear to be incapable of yielding either the cusps or the half-periodicity of the data. We suggest that these properties may occur with a more recently developed (and more sophisticated) version of hypernetted-chain theory, wherein ''elementary diagrams'' and three-body correlations are incorporated

General Hydrodynamics of He-3-a in Finite Magnetic-Fields

Journals published by the American Physical Society can be found at http://journals.aps.org

Screening and Tunneling at Metal-Surfaces

Journals published by the American Physical Society can be found at http://journals.aps.org

Low-Frequency Electromagnetic Response Function for Strong-Coupling Superconductors

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Phase-Diagram of Ultrathin Ferromagnetic-Films with Perpendicular Anisotropy

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Theory of first-order layering transitions in thin helium films

Journals published by the American Physical Society can be found at http://journals.aps.org/Thin liquid He-4 films on graphite show evidence of layered growth with increasing number density via a succession of first-order phase transitions. These so-called ''layering transitions'' separate uniformly covering phases, such as monolayers and bilayers. The present work is a detailed theoretical study of such layering transitions using a Maxwell construction. We model the graphite surface by a strong substrate potential, and using a microscopic variational theory we obtain the uniform coverage solutions for liquid helium. For each layer, the theory yields the chemical potential mu and surface tension alpha as functions of coverage n, and from this we deduce mu(a). For each set of adjacent layers, we then obtain the crossing point in the curves of mu(alpha). In this way we obtain the values of mu, alpha, and surface coverages for the transition. Particular attention is paid to the monolayer-bilayer transition

Gene therapy for carcinoma of the breast: Genetic ablation strategies

The gene therapy strategy of mutation compensation is designed to rectify the molecular lesions that are etiologic for neoplastic transformation. For dominant oncogenes, such approaches involve the functional knockout of the dysregulated cellular control pathways provoked by the overexpressed oncoprotein. On this basis, molecular interventions may be targeted to the transcriptional level of expression, via antisense or ribozymes, or post-transcriptionally, via intracellular single chain antibodies (intrabodies). For carcinoma of the breast, these approaches have been applied in the context of the disease linked oncogenes erbB-2 and cyclin D(1), as well as the estrogen receptor. Neoplastic revision accomplished in modal systems has rationalized human trials on this basis

Statics and Dynamics of Spin and Electric Dipoles in 3-Dimension, 4-Dimension, and Other Dimensions

Journals published by the American Physical Society can be found at http://journals.aps.org