Convergence of series of dependent φ-subgaussian random variables

The almost sure convergence of weighted sums of φ-subgaussian m-acceptable random variables is investigated. As corollaries, the main results are applied to the case of negatively dependent and m-dependent subgaussian random variables. Finally, an application to random Fourier series is presented.     

Electronic properties of nonhomovalent alloys: A study of the b.c.c. Li−Mg solid solution

Summary The influence of the alloying on the electronic properties of the b.c.c. Li−Mg solid solution has been investigated within the KKR-CPA framework. Such an influence has been studied by computing the band structure, Fermi surface, soft X-ray spectra, residual resistivity and Auger spectra for chosen values of the composition. The theoretical results we obtained are in fair agreement with the surface existing experimental data and support the view that also in ?simple metals? alloys care has to be taken in studying such systems in terms of low-order perturbation approaches.

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Riassunto Sono state studiate varie proprietà elettroniche delle leghe di Li−Mg nell’intervallo di concentrazione in cui questi sistemi cristallizzano nel reticolo b.c.c. In particolare sono state calcolate la struttura a bande, le superfici di Fermi, la resistività residua, gli spettri X ed Auger e si sono confrontati i risultati con i dati sperimentali esistenti. Il buon accordo fra risultati teorici e dati sperimentali indica che, anche per leghe di metalli semplici, gli approcci perturbativi a basso ordine possono essere insufficienti a descrivere il comportamento di tali sistemi.

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Резюме В рамках KKR-CPA исследуется влияние процесса сплавления на электронные свойства объемноцетририованного кубического твердого раствора Li−Mg. Проводятся вычисления зонной структуры, поверхности Ферми, спектров мягкого рентгеновского излучения, остаточного сопротивления и Ож-ye-спектров для выбранных величин состава. Полученные теоретические величины хорошо согласуются с существуюими экспериментальными данными.

     

Nonbinary convolutional codes derived from group character codes

New families of unit memory as well as multi-memory nonbinary convolutional codes are constructed algebraically in this paper. These convolutional codes are derived from the class of group character codes. The proposed codes have basic generator matrices, consequently, they are noncatastrophic. Additionally, the new code parameters are better than the ones available in the literature.     

Long-term diffusive samplers for the indoor air quality evaluation

Three kinds of diffusion samplers, conceived to perform long-term samplings in indoor sites are illustrated in this work. Two of them, in part deriving from the previous "Analyst for VOC" device, extend the field of application up to the semi-volatile organic compounds (SVOC), PAHs and nicotine in particular. A third device, which employs a basic barium hydroxide solution as an absorbing medium, is proposed for the determination of carbon dioxide levels which indicate the air change quality in the indoor sites. Laboratory and field experiments, performed in order to assess the reliability of the proposed devices, are shown. A monthly monitoring campaign, performed at three private apartments in Rome and its outskirts highlights that the indoor pollution levels are a complex function of various concurrent and opposite factors, like external air pollution, internal sources, air change rate and sink effect of surfaces, which contribute to depletion phenomena through adsorption and/or decomposition processes.     

On large deviations for some sequences of weighted means of Gaussian processes

In this paper we study some sequences of weighted means of continuous real valued Gaussian processes. More precisely we consider suitable generalizations of both arithmetic and logarithmic means of a Gaussian process with covariance function which satisfies either an exponential decay condition or a power decay condition. Our aim is to provide limits of variances of functionals of such weighted means which allow the application of some large deviation results in the literature.     

Theoretical investigation of histidine-tryptophan preferential interactions

Several histidine-tryptophan complexes (either stacked or T-shaped), derived from the crystal structures available in the Brookhaven Protein Data Bank, have been examined with molecular mechanics (MM), using the Tripos force field with Gasteiger-Hückel charges, whose trend was found to be analogous to the AMBER or CHARMM ones. The MM results were compared to the ab initio MP2 results, with and without counterpoise (CP) correction, previously obtained using extended basis sets on 5-methylimidazole and indole as model systems. MM seems to underestimate the interaction energy between the two monomers when compared to the uncorrected MP2 results, while the agreement is much better after including the CP correction at the MP2 level in all cases. MM was thus used to qualitatively analyse the dependence of the stacking energy on the ring rotation at a variable distance and ring centroid displacement for these systems, while keeping the rings in parallel planes. An analogous study was carried out for a T-shaped adduct. Received: 24 March 1998 / Accepted: 3 September 1998 / Published online: 1 February 1999