3,946 research outputs found
First Principles LCGO Calculation of the Magneto-optical Properties of Nickel and Iron
We report a first principles, self-consistent, all electron, linear
combination of Gaussian orbitals (LCGO) calculation of a comprehensive
collection of magneto-optical properties of nickel and iron based on density
functional theory. Among the many magneto-optical effects, we have studied the
equatorial Kerr effect for absorption in the optical as well as soft X-ray
region, where it is called X-ray magnetic linear dichroism (X-MLD). In the
optical region the effect is of the order of 2\% while in the X-ray region it
is of the order of 1\% for the incident angles considered. In addition, the
polar Kerr effect, X-ray magnetic circular dichroism (X-MCD) and total X-ray
absorption at the L edges, soft X-ray Faraday effect at the L
edges have also been calculated. Our results are in good agreement with
experiments and other first principles methods that have been used to calculate
some of these properties.Comment: 22 pages RevTex. 8 figures submitted separately as a uuencoded,
compressed tar fil
Optical Zener-Bloch oscillations in binary waveguide arrays
Zener tunneling in a binary array of coupled optical waveguides with
transverse index gradient is shown to produce a sequence of regular or
irregular beam splitting and beam recombination events superimposed to Bloch
oscillations. These periodic or aperiodic Zener-Bloch oscillations provide a
clear and visualizable signature in an optical system of coherent multiband
dynamics encountered in solid-state or matter-wave system
Online Convex Optimization with Binary Constraints
We consider online optimization with binary decision variables and convex
loss functions. We design a new algorithm, binary online gradient descent
(bOGD) and bound its expected dynamic regret. We provide a regret bound that
holds for any time horizon and a specialized bound for finite time horizons.
First, we present the regret as the sum of the relaxed, continuous round
optimum tracking error and the rounding error of our update in which the former
asymptomatically decreases with time under certain conditions. Then, we derive
a finite-time bound that is sublinear in time and linear in the cumulative
variation of the relaxed, continuous round optima. We apply bOGD to demand
response with thermostatically controlled loads, in which binary constraints
model discrete on/off settings. We also model uncertainty and varying load
availability, which depend on temperature deadbands, lockout of cooling units
and manual overrides. We test the performance of bOGD in several simulations
based on demand response. The simulations corroborate that the use of
randomization in bOGD does not significantly degrade performance while making
the problem more tractable
The ecosystem and evolutionary contexts of allelopathy
Plants can release chemicals into the environment that suppress the growth and establishment of other plants in their vicinity, a process known as ‘allelopathy’. However, chemicals with allelopathic functions have other ecological roles, such as plant defense, nutrient chelation, and regulation of soil biota in ways that affect decomposition and soil fertility. These ecosystem-scale roles of allelopathic chemicals can augment, attenuate or modify their community-scale functions. In this review we explore allelopathy in the context of ecosystem properties, and through its role in exotic invasions consider how evolution might affect the intensity and importance of allelopathic interactions
Faculty and teacher candidate computer self -efficacy and the relationship of faculty computer self -efficacy, technology professional development, and technology use
The purpose of this study was to examine the possible relationship among faculty computer self-efficacy, technology professional development, and the extent of technology use in Louisiana\u27s college and university classrooms. Additionally, faculty computer self-efficacy and teacher candidate computer self-efficacy were compared.
Participation was voluntary, involving higher education faculty and teacher candidates from the nineteen teacher preparation institutions within Louisiana. Faculty completed online surveys. A 30-item Likert-type scale was used to measure computer self-efficacy. Faculty also reported their involvement in technology training over the last five years and their technology use in the classroom. Teacher candidates completed either an online or print copy of the computer self-efficacy survey.
Data analysis involved a factor analysis of the computer self-efficacy scale, the identification of five computer self-efficacy constructs, a 4 x 3 ANOVA, and contingency coefficients to determine the correlation of nonparametric items.
Results of this study indicate a significant relationship between faculty computer self-efficacy and the extent of technology use. A significant relationship between technology professional development and technology use was also detected. Analysis of the data failed to confirm an interactive effect between faculty computer self-efficacy and technology professional development related to technology use. Results suggest an inverse relationship between tenure and computer self-efficacy, with observed tenured faculty members\u27 computer self-efficacy scores lower than expected scores. The results of this study also found no difference in faculty members\u27 computer self-efficacy and teacher candidates\u27 computer self-efficacy
The U(1)-Higgs Model: Critical Behaviour in the Confinig-Higgs region
We study numerically the critical properties of the U(1)-Higgs lattice model,
with fixed Higgs modulus, in the region of small gauge coupling where the Higgs
and Confining phases merge. We find evidence of a first order transition line
that ends in a second order point. By means of a rotation in parameter space we
introduce thermodynamic magnitudes and critical exponents in close resemblance
with simple models that show analogous critical behaviour. The measured data
allow us to fit the critical exponents finding values in agreement with the
mean field prediction. The location of the critical point and the slope of the
first order line are accurately given.Comment: 21 text pages. 12 postscript figures available on reques
Women disunited : Margaret Atwood\u27s The Handmaid\u27s Tale as a critique of feminism
While there is plenty of traditional feminist critique of male power structures in Atwood\u27s works, and particularly in The Handmaid\u27s Tale, this thesis argues that the power structure of Gilead (the biblically-inflected nation Atwood imagines) also critiques the feminine roles that support and enable the repression of other women. Placing the novel in the contexts of Atwood\u27s career, feminism, and dystopian literature, provides a fuller understanding of how the novel functions as an expression of the disunity of women.
Thus, this thesis turns the focus of The Handmaid\u27s Tale from the consequences of patriarchal control and traditional misogyny, to the matriarchal network, and a new form of misogyny: women\u27s hatred of women. Read thusly, The Handmaid\u27s Tale becomes a prophetic call to action
Abnormal emotional experience in schizophrenia
Ambivalence is defined as the state of simultaneously experiencing antithetical emotions towards a single attitude object (Bleuler, 1911/1950). Recent studies have evidenced ambivalence as a prominent aspect of schizophrenia patients’ in-the-moment emotional experiences (Cohen & Minor, 2010; Trémeau et al., 2009). The present study extended this line of work through the use of an experimental mood-induction methodology to explore the amount, frequency, and average duration of univalent positive, negative, and ambivalent emotional episodes within individuals with schizophrenia and those without psychiatric disturbance. The results indicate that, when exposed to a film clip stimulus selected for its documented (Larsen & McGraw, 2011) capacity to induce ambivalent emotions, individuals with and without schizophrenia do not reliably differ in any measured dimension of univalent or ambivalent emotional experience. Potential explanations for observed inconsistencies in the schizophrenia emotional experience literature are reviewed and study limitations as well as directions for future research are discussed
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