Immobilized cells in microbial nitrate reduction

The microorganismPseudomonas denitrificans was immobilized in alginate. These immobilized cells were capable of reducing 0.8 mg NO ₃ ^- /min/g wet weight of cells.     

Computational study of the lowest triplet state of ruthenium polypyridyl complexes used in artificial photosynthesis

The potential energy surfaces of the first excited triplet state of some ruthenium polypyridyl complexes were investigated by means of density functional theory. Focus was placed on the interaction between the geometrical changes accompanying the photoactivity of these complexes when used as antenna complexes in artificial photosynthesis and dye-sensitized solar cells and the accompanying changes in electronic structure. The loss process (3)MLCT --> (3)MC can be understood by means of ligand-field splitting, traced down to the coordination of the central ruthenium atom.     

Perceptual evaluations of voice scatter in unison choir sounds

The preferences of experienced listeners for pitch and formant frequency dispersion in unison choir sounds were explored using synthesized stimuli. Two types of dispersion were investigated: (a) pitch scatter, which arises when voices in an ensemble exhibit small differences in mean fundamental frequency, and (b) spectral smear, defined as such dispersion of formants 3 to 5 as arises from differences in vocal tract length. Each stimulus represented a choir section of five bass, tenor, alto, or soprano voices, producing the vowel [u], [a], or [w]. Subjects chose one dispersion level out of six available, selecting the “maximum tolerable” in a first run and the “preferred” in a second run. The listeners were very different in their tolerance for dispersion. Typical scatter choices were 14 cent standard deviation for “tolerable” and 0 or 5 cent for “preferred.” The smear choices were less consistent; the standard deviations were 12 and 7%, respectively. In all modes of assessment, the largest dispersion was chosen for the vowel [u] on a bass tone. There was a vowel effect on the smear choices. The effects of voice category were not significant.     

On the evaluation of spin–orbit coupling matrix elements in a spin‐adapted basis

In the present article, we outline a simple scheme for generating configuration interaction matrix elements for spin–orbit interactions in molecules. The procedure leads to a close parallelism with spin‐free permutation‐group approaches. Unitary shift operators were successfully used on the orbital space to generate the matching permutations necessary to evaluate the required matrix elements. The procedure is adequately illustrated using examples. ©1999 John Wiley & Sons, Inc. Int J Quant Chem 73: 23–27, 1999     

Spin coupling in shake-up processes

The treatment of spin coupling in calculations of shake-up states in core photoelectron processes is reviewed and the problems arising when the equivalent core approximation is used to model the core hole are discussed. A method for approximating the intensity of the triplet-coupled doublet state in semiempirical calculations is proposed. The intensities of the triplet-coupled doublet states in N₂, formaldehyde, and aniline core ionization spectra are calculated. © 1997 John Wiley & Sons, Inc. Int J Quant Chem 63: 189–196, 1997     

Indexing scheme for classes of 𝒮N; partitions of N

The classes of the symmetric group 𝒮_N are identified by partitions of N. In this work an indexing scheme is presented which provides a dense enumeration of the classes of 𝒮_N. The method is based on a graphical representation of partitions of N, which also enables the determination of the class corresponding to a given number. © 1997 John Wiley & Sons, Inc. Int J Quant Chem 64 : 421–426, 1997     

Chance-constrained activity analysis

The methods of activity analysis (Koopmans [6,7]) are re-examined in the presence of technological uncertainty. In particular, such uncertainty arises when new emerging technologies are employed in the production process and/or when new product designs are being developed. Both input coefficients and output coefficients may be uncertain. If activity levels are to be determined and fixed a priori, one may not be able to require in advance that total output suffice to cover total demand. (Indeed, demand itself may also be uncertain.) Instead, the requirement is written as a chance-constraint, to hold on some predetermined probability level only.The purpose of the present note is to discuss the economic properties of the resulting optimal solution. The certainty equivalent of the chance-constrained program and the corresponding Kuhn-Tucker conditions are written down. At the point of optimum, each producer will hold some inventories of finished goods as a contingency against variation in the output coefficients and in demand. Equilibrium prices will suffice to provide each activity some expected positive profit (an explicit formula for the calculation of the magnitude of this profit is provided).In choosing between several risky activities, each producer may attempt to establish an optimal portfolio of activities, providing a trade-off between expected cost and risk. The nature of an emerging theory of activity portfolios, developed along the lines of standard concepts in financial portfolio analysis, is indicated.     

Cosmic ray spectrum measured by the PRISMA-32 setup

The results of measurements of the spectrum of extensive air showers (EASs) by the number of neutrons detected by the PRISMA-32 setup are presented. The neutron component is formed during the interaction of high-energy shower hadrons with nuclei of atmospheric and Earth’s surface atoms. The PRISMA-32 setup consists of 32 en-detectors and operates in the continuous mode for about 5 years.