Comment on: “Confined states in two-dimensional flat elliptic quantum dots and elliptic quantum wires” [Physica E 11 (2001) 345]

We argue that the two-dimensional elliptic quantum dot problem with finite barrier cannot be exactly solved, contrary to a recent assertion (van den Broek and Peeters, Physica E 11 (2001) 345. We also prove it explicitly by numerically calculating the correct energy spectrum.     

Microcalorimetric measurements of the metabolic activity by bacteria and fungi in some Brazilian soils amended with different organic matter

The effect of bacterial and fungal activities on organic matter degradation in Brazilian soils was studied by a microcalorimetric method. Bacteria and fungi isolated from tropical soils and added to: Rhodic eutrudox (R), Typic eutrudox (V) and Quartzipsamment (Q) soils amended separately with moisture (control) (A) and 25% of cattle manure (E), municipal refuse compost (L), earthworm casts (H) or 23 μg of trifluralin (T) were investigated. The number of colony forming units in soil suspension was quantified by microscopy and inoculated in respective soil. All processes were measured at intervals of 7 days over a period of 35 days. The exothermic thermal effect (μJ) per cm³ of bacteria or fungi per gram of dry soil, respectively, for each substrate was: [(9±1), (4±1)] RA; [(478±24), (105±5)] RE; [(121±6), (71±4)] RL; [(121±6), (71±4)] RH; [(8±1); (3±1)] RT; [(10±1), (9±1] VA; [(347±17), (261±13)] VE; [(71±4), (28±1)] VL; [(22±1), (33±2)] VH; [(7±1), (10±1)] VT; [(19±1), (12±1)] QA; [(1301±65), (46±2)] QE; [(89±4), (9±1)] QL; [(130±7), (11±1)] QH; [(32±2), (8±1)] QT. The calorimetric values are higher for bacteria than for fungi. In general, the results showed higher activities in the soil amended with cattle manure than with other additives.     

A tight-binding study of LUMO states in ellipsoidal silicon nanocrystals

In this paper we report on tight-binding calculations of lowest unoccupied molecular orbitals states for silicon ellipsoidal nanocrystals. The electronic structure has been calculated for different nanocrystal shapes either keeping constant or varying the number of silicon atoms. We have found that changing the ellipsoid aspect ratio a non-obvious energy level structure is obtained. The implications for the infrared optical transitions and their relationship with the polarization of the radiation involved are discussed.     

Quantum Properties of Odd Excited Negative Binomial States of the Radiation Field

The odd excited negative binomial states are introduced using the photon creation operator by repeated application on negative binomialstates. These states interpolate between the odd displaced Fock states and the odd excited pure thermal states. In this paper both squeezing phenomena (normal squeezing and amplitude squared squeezing) are discussed. Besides discussion of the Glauber second-order correlation function, investigations are carried out for the quasi-probability distribution functions (Wigner function and Q-function). Finally the Pegg-Barnett phase probability distribution is computed for these states.     

Semiempirical calculation of the fine structure of the indium ion

The fine-structure parameters of a series of configurations of the first ion of indium and the gyromagnetic ratios in intermediate coupling are calculated by a semiempirical method in the single-configuration approximation.     

Decay-mode independent searches for new scalar bosons with the OPAL detector at LEP

This paper describes topological searches for neutral scalar bosons S⁰ produced in association with a Z⁰ boson via the Bjorken process at centre-of-mass energies of 91 GeV and 183-209 GeV. These searches are based on studies of the recoil mass spectrum of and events and on a search for with and S or photons. They cover the decays of the S⁰ into an arbitrary combination of hadrons, leptons, photons and invisible particles as well as the possibility that it might be stable. No indication for a signal is found in the data and upper limits on the cross section of the Bjorken process are calculated. Cross-section limits are given in terms of a scale factor k with respect to the Standart Model cross section for the Higgs-strahlung process . These results can be interpreted in general scenarios independently of the decay modes of the S⁰. The examples considered here are the production of a single new scalar particle with a decay width smaller than the detector mass resolution, and for the first time, two scenarios with continuous mass distributions, due to a single very broad state or several states close in mass. Received: 13 March 2002 / Published online: 19 February 2003     

Use of the two-moment boundary condition in the problem of rarefied gas slip over a solid cylindrical surface

The slip velocity of a rarefied gas nonuniform in temperature and mass velocity is calculated for gas slip over the surface of a right circular cylinder. The calculation uses the two-moment boundary condition in an approximation linear in Knudsen number. Corrections to the slip velocity that are due to the interface curvature, volume temperature stresses, and nonuniform temperature distribution in the Knudsen layer are studied as func-tions of the accommodation coefficients in the first two moments of the distribution function. The Bhatnagar-Gross-Krook model of the Boltzmann kinetic equation is employed as the basic equation for the gas state.     

Automorphisms and Derivations of Exceptional Simple Lie Algebras of Family <Emphasis Type="Italic">R</Emphasis>

In the paper we describe automorphisms and derivations of simple Lie algebras of family R. The Lie algebra of the automorphism group is found. Bibliography: 11 titles.__________Translated from Zapiski Nauchnykh Seminarov POMI, Vol. 305, 2003, pp. 165–186.