Analytical Hartree-Fock gradients for periodic systems

We present the theory of analytical Hartree-Fock gradients for periodic systems as implemented in the code CRYSTAL. We demonstrate how derivatives of the integrals can be computed with the McMurchie-Davidson algorithm. Highly accurate gradients with respect to nuclear coordinates are obtained for systems periodic in 0,1,2 or 3 dimensions.Comment: accepted by International Journal of Quantum Chemistr

Adhesion between atomically pure metallic surfaces, part IV Semiannual report

Adhesion between metal couples in vacuum environment and use of contact resistance measurements to evaluate surface contaminatio

Effect of card play on perceived life satisfaction and self esteem of older adults

STATEMENT OF THE PROBLEM: The problem of this study was to (a) assess the effect of playing cards on the level of perception of life satisfaction and self-esteem in older adults and (b) determine if there was any difference in the perceived level of life satisfaction and self-esteem between older adults who played cards with other people compared with those who played cards on a computer. PURPOSE OF THE STUDY: The purpose of this study was to examine a potentially cost effective way to improve the level of perception of life satisfaction and self-esteem of the older adult. METHODS: Single-subject repeated measures A-B-A design was used for the three phase experiment. Data were collected from all subjects across a total of six weeks. Phase (A) was the establishment of the baseline before the start of treatment phase (B). Subjects in the study were tested with two measurement instruments of Life Satisfaction and Self-Esteem before treatment of card play on the computer or face-to-face card play, were administered. Midpoint and end-treatment tests were given at the second and fourth weeks. These two testing sessions measured phase (B), the treatment phase of the experiment. Two weeks after the treatment phase, tests were given as the post-treatment (A) last phase of the experiment, measuring the subjects post treatment return to baseline. Data analysis: data collected from the four testing periods were entered into a Microsoft 2007 Excel file. Individual and combined trend line charts were generated for descriptive analysis, interpretation, and explanation of the trend lines across times of testing.Submitted to the faculty of the University Graduate School in partial fulfillment of the requirements for the degree Master of Science in the School of Health, Physical Education, and Recreation Indiana University May 201

Discrepancy between Parents and Children in Reporting of Distress and Impairment: Association with Critical Symptoms

Background: We examined discrepant parent–child reports of subjective distress and psychosocial impairment. Method: Parent–child pairs (N = 112 pairs) completed the Health Dynamics Inventory at intake for outpatient therapy. Results: Average parent scores were significantly higher than average child scores on distress, impairment, and externalizing symptoms, but not internalizing symptoms. There were significant associations between parent–child discrepancy (i.e. children who reported greater distress or impairment than parents or vice versa) and child endorsement of several notable symptoms (rapid mood swings, panic, nightmares, and suicidal ideation). Conclusion: Parents tended to report more externalizing symptoms, distress, and impairment than children reported; however, when children report more distress and impairment than parents, this may indicate serious psychological problems

Algebraic grid generation using tensor product B-splines

Finite difference methods are more successful if the accompanying grid has lines which are smooth and nearly orthogonal. The development of an algorithm which produces such a grid when given the boundary description. Topological considerations in structuring the grid generation mapping are discussed. The concept of the degree of a mapping and how it can be used to determine what requirements are necessary if a mapping is to produce a suitable grid is examined. The grid generation algorithm uses a mapping composed of bicubic B-splines. Boundary coefficients are chosen so that the splines produce Schoenberg's variation diminishing spline approximation to the boundary. Interior coefficients are initially chosen to give a variation diminishing approximation to the transfinite bilinear interpolant of the function mapping the boundary of the unit square onto the boundary grid. The practicality of optimizing the grid by minimizing a functional involving the Jacobian of the grid generation mapping at each interior grid point and the dot product of vectors tangent to the grid lines is investigated. Grids generated by using the algorithm are presented

A technique for breaking ice in the path of a ship

A technique is described for breaking ice in the path of a ship. A laser is placed on the bow of the ship with apparatus to scan the ice in the path of the ship with the laser beam. The beam cuts or shatters the ice, enabling the ship to break the ice in its path

Hybrid functionals within the all-electron FLAPW method: implementation and applications of PBE0

We present an efficient implementation of the PBE0 hybrid functional within the full-potential linearized augmented-plane-wave (FLAPW) method. The Hartree-Fock exchange term, which is a central ingredient of hybrid functionals, gives rise to a computationally expensive nonlocal potential in the one-particle Schroedinger equation. The matrix elements of this exchange potential are calculated with the help of an auxiliary basis that is constructed from products of FLAPW basis functions. By representing the Coulomb interaction in this basis the nonlocal exchange term becomes a Brillouin-zone (BZ) sum over vector-matrix-vector products. We show that the Coulomb matrix can be made sparse by a suitable unitary transformation of the auxiliary basis, which accelerates the computation of the vector-matrix-vector products considerably. Additionally, we exploit spatial and time-reversal symmetry to identify the nonvanishing exchange matrix elements in advance and to restrict the k summations for the nonlocal potential to an irreducible set of k points. Favorable convergence of the self-consistent-field cycle is achieved by a nested density-only and density-matrix iteration scheme. We discuss the convergence with respect to the parameters of our numerical scheme and show results for a variety of semiconductors and insulators, including oxide materials, where the PBE0 hybrid functional improves the band gaps and the description of localized states in comparison with the PBE functional. Furthermore, we find that in contrast to conventional local exchange-correlation functionals ferromagnetic EuO is correctly predicted to be a semiconductor.Comment: 15 pages, 6 figures, 2 table

Digital Repository of Mathematical Formulae

The purpose of the NIST Digital Repository of Mathematical Formulae (DRMF) is to create a digital compendium of mathematical formulae for orthogonal polynomials and special functions (OPSF) and of associated mathematical data. The DRMF addresses needs of working mathematicians, physicists and engineers: providing a platform for publication and interaction with OPSF formulae on the web. Using MediaWiki extensions and other existing technology (such as software and macro collections developed for the NIST Digital Library of Mathematical Functions), the DRMF acts as an interactive web domain for OPSF formulae. Whereas Wikipedia and other web authoring tools manifest notions or descriptions as first class objects, the DRMF does that with mathematical formulae. See http://gw32.iu.xsede.org/index.php/Main_Page

Modeling the emergence of universality in color naming patterns

The empirical evidence that human color categorization exhibits some universal patterns beyond superficial discrepancies across different cultures is a major breakthrough in cognitive science. As observed in the World Color Survey (WCS), indeed, any two groups of individuals develop quite different categorization patterns, but some universal properties can be identified by a statistical analysis over a large number of populations. Here, we reproduce the WCS in a numerical model in which different populations develop independently their own categorization systems by playing elementary language games. We find that a simple perceptual constraint shared by all humans, namely the human Just Noticeable Difference (JND), is sufficient to trigger the emergence of universal patterns that unconstrained cultural interaction fails to produce. We test the results of our experiment against real data by performing the same statistical analysis proposed to quantify the universal tendencies shown in the WCS [Kay P and Regier T. (2003) Proc. Natl. Acad. Sci. USA 100: 9085-9089], and obtain an excellent quantitative agreement. This work confirms that synthetic modeling has nowadays reached the maturity to contribute significantly to the ongoing debate in cognitive science.Comment: Supplementery Information available here http://www.pnas.org/content/107/6/2403/suppl/DCSupplementa