Spinor algebra and null solutions of the wave equation

In this paper we exploit the ideas and formalisms of twistor theory, to show how, on Minkowski space, given a null solution of the wave equation, there are precisely two null directions in $\ker df$, at least one of which is a shear-free ray congruence

Kinetics of diffusional droplet growth in a liquid/liquid two-phase system

This report contains experimental results for the interdiffusion coefficient of the system, succinonitrile plus water, at a number of compositions and temperatures in the single phase region of the phase diagram. The concentration and temperature dependence of the measured diffusion coefficient has been analyzed in terms of Landau - Ginzburg theory, which assumes that the Gibb free energy is an analytic function of its variables, and can be expanded in a Taylor series about any point in the phase diagram. At most points in the single phase region this is adequate. Near the consolute point (critical point of solution), however, the free energy is non-analytic, and the Landau - Ginzburg theory fails. The solution to this problem dictates that the Landau - Ginzburg form of the free energy be replaced by Widom scaling functions with irrational values for the scaling exponents. As our measurements of the diffusion coefficient near the critical point reflect this non-analytic character, we are preparing for publication in a refereed journal a separate analysis of some of the data contained herein as well as some additional measurements we have just completed. When published, reprints of this article will be furnished to NASA

Liberal Arts 2.0

The title, Liberal Arts 2.0., stems from the term Web 2.0, which refers to the recent evolution of the Web as interactive, participatory, collaborative and collective. Web 2.0 includes blogs, wikis, user-generated media, social networking: like much of what it describes, the definition is amorphous and inexact. Baird believes that Web 2.0 and all that it implies will necessitate a revision of the way we do liberal arts and thus the title “Liberal Arts 2.0.” Her premise: that a liberal arts college is a place where teaching and research are improved by digital tools, where students are taught to negotiate and synthesize the sea of information available to them, where important ethical questions are discussed and aired. It is a place where the liberal arts are evolving into version 2.0., And that a liberal arts college is also exactly where students should be in this digital era

A study of methods for estimating parameters in rational polynomial models

“The use of rational polynomials for approximating surfaces is investigated in this study. In particular, methods for estimating parameters for a rational polynomial model were investigated. A method is presented for finding initial estimates of the parameters. Two iterative methods are discussed for improving those estimates in an attempt to minimize the sum of the squares of the residuals. These two methods are (1) Scarborough’s Method for applying the theory of least squares to nonlinear models and (2) the Method of Steepest Descent. Data from two functions were chosen and approximated as illustrations. Each set of data was used two ways, (1) as generated, and (2) with random errors added, thus giving four examples. Scarborough’s Method for improving the starting values was very effective, for the examples chosen, and the approximations were excellent. The study indicates, therefore, that rational polynomials have good potential as useful functions for surface approximants --Abstract, page ii

Metaphysical conceits involving death in the writings of John Donne

Much has been written in the past fifty years about John Donne and his work. His troubled life and enigmatic writings have made him seem a kindred spirit to a confused age. To our day the dissonant, abrupt, and calculatedly reckless style and the concern with the harsh realities of love and death have relevance which heretofore had been misunderstood or ignored

Oculomotor Deficits in Diseases of the Basal Ganglia: Parkinson\u27s and Huntington\u27s Diseases

Oculomotor deficits are now recognized as being present in several neurological diseases of the basal ganglia. The present report will focus primarily on those observed in Huntington\u27s and Parkinson\u27s diseases. Neuronal cell loss in the pars compacta of the substantia nigra, degeneration of the nigrostriatal pathway, and consequent depletion of the neurotransmitter dopamine is the most obvious etiological abnormality in Parkinson\u27s disease. Huntington\u27s disease, on the other hand, involves the selective genetically-driven atrophy of the striatum (caudate and putamen). In order to attempt to understand oculomotor dysfunction, as a component of basal ganglia disease, it is necessary to first establish a definition of the basal ganglia, its relevant connections, and their associated neurotransmitters and functions

Biharmonic Riemannian submersions from 3-manifolds

An important theorem about biharmonic submanifolds proved independently by Chen-Ishikawa [CI] and Jiang [Ji] states that an isometric immersion of a surface into 3-dimensional Euclidean space is biharmonic if and only if it is harmonic (i.e, minimal). In a later paper [CMO2], Cadeo-Monttaldo-Oniciuc shown that the theorem remains true if the target Euclidean space is replaced by a 3-dimensional hyperbolic space form. In this paper, we prove the dual results for Riemannian submersions, i.e., a Riemannian submersion from a 3-dimensional space form of non-positive curvature into a surface is biharmonic if and only if it is harmonic