Acoustic applications of wood wool cement slabs

Wood wool cement slabs, which are available in a variety of different forms, have proved to be effective for many acoustic applications. Some recent examples are described and compared with the expected behaviour based on laboratory measurements of absorption coefficients or sound reduction indices. Field results are shown for comparison where these are available.     

Convective auto-oscillations in the components of binary stars

A study is made of the convection in a shell of matter in a star in a binary Keplerian system. Because the axial rotation and orbital revolution are not synchronous, there is a periodic modulation of the gravity field of the star by tidal forces. It is shown that under certain conditions one can have an auto-oscillatory regime in which the mean intensity of the oscillatory convective motions also varies periodically with the time.Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 2, pp. 149–155, March–April, 1981.     

The q-boson realizations of the quantum groups U q(B n)

We give explicit realization for the quantum enveloping algebras U _q(B _n). In these formulae the generators of the algebra are expressed by means of 2n–1 canonical q-boson pairs and one auxiliary representation of U _q(B _n–1)     

The new formulas for the eigenvectors of the Gaudin model in the <Emphasis Type="Italic">so</Emphasis>(5) case

In our recent paper we proposed new formulas for eigenvectors of the Gaudin model in sl(3) case. Similarly in this paper we used the standard Bethe Ansatz method for finding the eigenvectors and the eigenvalues in the so(5) case in an explicit form.     

Highest weight representation for Sklyanin algebra <Emphasis Type="Italic">sl</Emphasis>(3)(<Emphasis Type="Italic">u</Emphasis>) with application to the Gaudin model

We study the infinite-dimensional Sklyanin algebra sl(3)(u). Specifically we construct the highest weight representation for this algebra in an explicit form. Its application to the Gaudin model is mentioned.     

A prolog-based decision support system for computer capacity planning

This paper describes a project to implement a decision support system for computer capacity planning. The system provides an intelligent interface to the various models needed for this type of planning by assisting the user in model formulation, data manipulation, model execution, interpretation and manipulation of results. The implementation strategy is based on the integration of relational model and database management with logic. A modified version of a Prolog interpreter is utilized as the vehicle for this integrated strategy.This research was supported by Sandia National Laboratories Grant No. 56-3737. Sandia is managed by AT&T Technologies for the U.S. Department of Energy.     

Biostimulation of dermal fibroblast by sublethal Q-switched Nd:YAG 532 nm laser: collagen remodeling and pigmentation

The application of medical lasers in treating pigmented lesions has rapidly developed over the past decade. In both clinical and cosmetic application, melanin is targeted in pigmented areas and destroyed by the mechanism of selective photothermolysis. When laser radiation passes through superficial pigmented tissue, energy will be further reduced by dermal collagen scattering and absorption. Non-pigmented dermal fibroblasts will be exposed to co-incidental laser irradiation at lower energy levels. Biostimulation of dermal fibroblasts by low energy laser is reported in this paper. The Q-switched frequency doubled Nd:YAG 532nm laser used in clinical laser therapy was used in this study. Sublethal laser fluence was determined at 0.8J/cm(2) and used to stimulate normal human fibroblasts in monolayer culture. The results showed that there was no significant difference in collagen synthesis between the stimulated fibroblasts and controls. However, significant delay in collagen remodeling activity was demonstrated in the irradiated group by measuring fibroblast populated collagen lattice (FPCL) contraction. The stimulation of SCF, HGF and b-FGF gene expression was determined by RT-PCR analysis and demonstrated to vary between cases. Two out of six cell lineages that showed stronger responses to laser stimulation on SCF, HGF and b-FGF gene expressions were used to prepare conditioned media. The conditioned media from irradiated groups showed significant increase in SCF and b-FGF content and stimulated SK-mel-3 melanoma cells to synthesize more melanin in vitro. These results suggest that sublethal laser stimulation of fibroblasts may cause post-laser hyperpigmentation through production of melanogenic stimulatory cytokines. The degree of stimulation of SCF, HGF and b-FGF production varied between individual cell lineages, which may reflect the true variation of post-laser hyperpigmentation in clinical practice.     

The <Emphasis Type="Italic">q</Emphasis>-boson-fermion realizations of the quantum superalgebra <Emphasis Type="Italic">U</Emphasis><Subscript><Emphasis Type="Italic">q</Emphasis></Subscript>(<Emphasis Type="Italic">osp</Emphasis>(1/2))

We show that our construction of realizations for algebras and quantum algebras can be generalized to quantum superalgebras too. We studyan example of quantum superalgebra U _q (osp(1/2)) and give the boson-fermion realization with respect to one pair of q-boson operators and one pair of fermions.     

Summing perturbation expansions by means of renormalization group considerations

Renormalization group considerations are used to sum divergent perturbation expansions encountered in QCD or other quantum field theories. The method works even in the case when these expansions, considered in a fixed renormalization scheme (RS), are factorially divergent and of asymptotically constant sign. The results assume the form of convergent (under certain circumstances) expansions in a set of functions of a free parameter which specifies the procedure involved. It is argued that the relation of our results to conventional, formal perturbation expansions in a fixed RS in fact suggests the physical interpretation of this parameter and specifies its value.