5,505 research outputs found

    On the equivalence of LIST and DIIS methods for convergence acceleration

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    Self-consistent field extrapolation methods play a pivotal role in quantum chemistry and electronic structure theory. We here demonstrate the mathematical equivalence between the recently proposed family of LIST methods [J. Chem. Phys. 134, 241103 (2011); J. Chem. Theory Comput. 7, 3045 (2011)] with Pulay's DIIS [Chem. Phys. Lett. 73, 393 (1980)]. Our results also explain the differences in performance among the various LIST methods

    Actinide chemistry using singlet-paired coupled cluster and its combinations with density functionals

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    Singlet-paired coupled cluster doubles (CCD0) is a simplification of CCD that relinquishes a fraction of dynamic correlation in order to be able to describe static correlation. Combinations of CCD0 with density functionals that recover specifically the dynamic correlation missing in the former have also been developed recently. Here, we assess the accuracy of CCD0 and CCD0+DFT (and variants of these using Brueckner orbitals) as compared to well-established quantum chemical methods for describing ground-state properties of singlet actinide molecules. The f0f^0 actinyl series (UO22+_2^{2+}, NpO22+_2^{2+}, PuO22+_2^{2+}), the isoelectronic NUN, and Thorium (ThO, ThO2+^{2+}) and Nobelium (NoO, NoO2_2) oxides are studied.Comment: 8 page

    Size Characteristics of Electrosprayed Polyethylene Glycol Beads for Producing Tissue Engineering Scaffolds

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    Submersion Electrospraying involves the injection of a polymer solution with photo-initiator into an immiscible liquid under an electric field. This document will reveal the changes in size and yield percentage of poly(ethylene glycol) hydrogel beads created with submersion electrospraying and UV light photo-polymerization. The varied physical parameters include: polymer chain molecular weight, intensity of the electric field applied, cross-linker used, the distance from the syringe to the electrical grounding ring, the flowrate from the syringe, and the gauge size of the syringe needle. Once size from each physical parameter was characterized, bead sizes from 0.712mm to 0.150mm were used to produce tissue engineering scaffolds, and their effects on retention of PBS were characterized during degradation

    Embedology and Neural Estimation for Time Series Prediction

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    Time series prediction has widespread application, ranging from predicting the stock market to trying to predict future locations of scud missiles. Recent work by Sauer and Casdagli has developed into the embedology theorem, which sets forth the procedures for state space manipulation and reconstruction for time series prediction. This includes embedding the time series into a higher dimensional space in order to form an attractor, a structure defined by the embedded vectors. Embedology is combined with neural technologies in an effort to create a more accurate prediction algorithm. These algorithms consist of embedology, neural networks, Euclidean space nearest neighbors, and spectral estimation techniques in an effort to surpass the prediction accuracy of conventional methods. Local linear training methods are also examined through the use of the nearest neighbors as the training set for a neural network. Fusion methodologies are also examined in an attempt to combine several algorithms in order to increase prediction accuracy. The results of these experiments determine that the neural network algorithms have the best individual prediction accuracies, and both fusion methodologies can determine the best performance. The performance of the nearest neighbor trained neural network validates the applicability of the local linear training set

    Banking Sector Performance in Latin America: Market Power versus Efficiency

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    TSince the mid-1990s the banking sector in the Latin American emerging markets has experienced profound changes due to financial liberalisation, a significant increase in foreign investments and greater mergers activities often occurring following financial crises. The wave of consolidation and the rapid increase in market concentration that took place in most countries has generated concerns about the rise in banks’ market power and its potential effects on consumers. This paper advances the existing literature by testing the market power (Structure-Conduct-Performance and Relative Market Power) and efficient structure (X- and scale efficiency) hypotheses for a sample of over 2,500 bank observations in nine Latin American countries over 1997-2005. We use the Data Envelopment Analysis technique to obtain reliable efficiency measures. We produce evidence supporting the efficient structure hypotheses. The findings are particularly robust for the largest banking markets in the region, namely Brazil, Argentina and Chile. Finally, capital ratios and bank size seem to be among the most important factors in explaining higher than normal profits for Latin American banks.Structure-Conduct-Performance; Efficient Structure; Latin American banking; Data Envelopment Analysis (DEA).

    Banking Sector Performance in Some Latin American Countries: Market Power versus Efficiency

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    The wave of consolidation and the rapid increase in market concentration that took place in most Latin American countries has generated concerns about the rise in banks' market power and its potential effects on consumers. This paper advances the existing literature by testing the market power (Structure-Conduct-Performance and Relative Market Power) and efficient structure (X- and scale efficiency) hypotheses for a sample of over 2,500 bank observations in nine Latin American countries over 1997-2005. We use the Data Envelopment Analysis technique to obtain reliable efficiency measures. We produce evidence supporting the efficient structure hypotheses. Finally, capital ratios and bank size seem to be among the most important factors in explaining profits for these Latin American banks.Structure-Conduct-Performance, Efficient Structure, Banking System in Some Latin American Countries, Data Envelopment Analysis (DEA)

    Newsletter - 1977-02-10

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    https://scholarworks.utrgv.edu/kikadelagarzanews/1223/thumbnail.jp

    Newsletter - 1972-11-02

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    https://scholarworks.utrgv.edu/kikadelagarzanews/1118/thumbnail.jp

    Newsletter - 1971-08-12

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    https://scholarworks.utrgv.edu/kikadelagarzanews/1059/thumbnail.jp
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