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Statistical Weight (statistical + weight)

Distribution by Scientific Domains

Chemistry	50%

Selected Abstracts

European Momentum Strategies, Information Diffusion, and Investor Conservatism

EUROPEAN FINANCIAL MANAGEMENT, Issue 3 2005
John A. Doukas
G1; G11; G14 Abstract In this paper we conduct an out-of-sample test of two behavioural theories that have been proposed to explain momentum in stock returns. We test the gradual-information-diffusion model of Hong and Stein (1999) and the investor conservatism bias model of Barberis et al. (1998) in a sample of 13 European stock markets during the period 1988 to 2001. These two models predict that momentum comes from the (i) gradual dissemination of firm-specific information and (ii) investors' failure to update their beliefs sufficiently when they observe new public information. The findings of this study are consistent with the predictions of the behavioural models of Hong and Stein's (1999) and Barberis et al. (1998). The evidence shows that momentum is the result of the gradual diffusion of private information and investors' psychological conservatism reflected on the systematic errors they make in forming earnings expectations by not updating them adequately relative to their prior beliefs and by undervaluing the statistical weight of new information. [source]

4- and 4,5-Substituted N -Methoxythiazole-2(3H)-thiones , Preparation,UV/Vis Spectra, and Assignment of Electronic Transitions in Comparison to N -Methoxypyridine-2(1H)-thione Using Time-Dependent Density Functional Theory Calculations

EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 5 2005
Jens Hartung
Abstract Experimentally observed absorptions in UV/Vis spectra of N -methoxy-4-methylthiazole-2(3H)-thione, N -methoxy-5-(p -methoxyphenyl)-4-methylthiazole-2(3H)-thione, N -methoxypyridine-2(1H)-thione, and selected N -hydroxy derivatives thereof have been assigned to ,,,*-type transitions as dominating character, using the results from ab initio calculations [time-dependent density functional theory (TD)RI-BLYP/TZVPP]. Theory further predicts that electronic excitations in N -methoxythiazole-2(3H)-thiones on one side and N -meth-oxypyridine-2(1H)-thione on the other side differ significantly with respect to character and statistical weight of contributing transitions. These effects originate predominantly from contributions of the endocyclic sulfur atom onto orbital energies and shapes in thiazole-2(3H)-thiones, and may be intensified by substituents such as a p -methoxyphenyl group located in position 5. Since the majority of the calculated spectral differences between thiazole- and pyridinethiones refers to excitations of low intensity, the findings from the present study correlate with two important experimental facts: (i) Apart from minor shifts in the exact spectral location of UV/Vis absorptions, electronic spectra of N -hydroxy- or N -methoxy-substituted pyridine-2(1H)-thiones and thiazole-2(3H)-thiones are surprisingly similar in shape. (ii) N -alkoxypyridine-2(1H)-thiones and N -alkoxythiazole-2(3H)-thiones liberate upon UV/Vis excitation oxygen-centered radicals with a comparable efficiency. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005) [source]

Detecting bispectral acoustic oscillations from inflation using a new flexible estimator

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 4 2010
Martin Bucher
ABSTRACT We present a new flexible estimator for comparing theoretical templates for the predicted bispectrum of the cosmic microwave background (CMB) anisotropy to observations. This estimator, based on binning in harmonic space, generalizes the ,optimal' estimator of Komatsu, Spergel and Wandelt by allowing an adjustable weighting scheme for masking possible foreground and other contaminants and detecting particular noteworthy features in the bispectrum. The utility of this estimator is illustrated by demonstrating how acoustic oscillations in the bispectrum and other details of the bispectral shape could be detected in the future Planck data provided that fNL is sufficiently large. The character and statistical weight of the acoustic oscillations and the decay tail are described in detail. [source]

Determination of ,-helix N1 energies after addition of N1, N2, and N3 preferences to helix/coil theory

PROTEIN SCIENCE, Issue 4 2000
Jia Ke Sun
Abstract Surveys of protein crystal structures have revealed that amino acids show unique structural preferences for the N1, N2, and N3 positions in the first turn of the ,-helix. We have therefore extended helix-coil theory to include statistical weights for these locations. The helix content of a peptide in this model is a function of N-cap, C-cap, N1, N2, N3, C1, and helix interior (N4 to C2) preferences. The partition function for the system is calculated using a matrix incorporating the weights of the fourth residue in a hexamer of amino acids and is implemented using a FORTRAN program. We have applied the model to calculate the N1 preferences of Gln, Val, Ile, Ala, Met, Pro, Leu, Thr, Gly, Ser, and Asn, using our previous data on helix contents of peptides Ac-XAKAAAAKAAGY-CONH2. We find that Ala has the highest preference for the N1 position. Asn is the most unfavorable, destabilizing a helix at N1 by at least 1.4 kcal mol,1 compared to Ala. The remaining amino acids all have similar preferences, 0.5 kcal mol,1 less than Ala. Gln, Asn, and Ser, therefore, do not stabilize the helix when at N1. [source]