A Method for Solving Certain Quadratic Programming Problems Arising in Nonsmooth Optimization

We present a finite algorithm for minimizing a piecewise linearconvex function augmented with a simple quadratic term. To solvethe dual problem, which is of least-squares form with an additionallinear term, we include in a standard active-set quadratic programmingalgorithm a new column-exchange strategy for treating positivesemidefinite problems. Numerical results are given for an implementationusing the Cholesky factorization.     

An Exact Penalty Function Algorithm for Non-smooth Convex Constrained Minimization Problems

This paper presents a readily implementable algorthm for solvingconstrained minimization problems invlving (not necessarilysmooth) convex functions. The algorithm minimizes an exact penaltyfunction via the aggregater subgradient method for unconstrainedminimization, A scheme for automatic limitaion of penalty growthis given. The algorithm is globally convergent under mild assumptions.     

BV Structure of the Cohomology of Nilpotent Subalgebras and the Geometry of(W) Strings

Given a simple, simply laced, complex Lie algebra corresponding to the Lie group G, let be thesubalgebra generated by the positive roots. In this Letter we construct aBV algebra whose underlying graded commutative algebra is given by the cohomology, with respect to , of the algebra of regular functions on G with values in . We conjecture that describes the algebra of allphysical (i.e., BRST invariant) operators of the noncritical string. The conjecture is verified in the two explicitly known cases, ₂ (the Virasoro string) and ₃ (the string).     

Quantum cluster equilibrium theory treatment of hydrogen-bonded liquids: water,methanol and ethanol

The quantum cluster equilibrium (QCE) theory was used in order to predict the composition of the hydrogen bonded liquids: water, methanol and ethanol. The calculations were based on high accuracy theoretical data obtained at the DFT/B3LYP/6-311 G(d,p) level of theory. All investigated liquids are predicted to be composed of big clusters: hexamers in the case of water, tetramers, pentamers, hexamers and heptamers in the case of methanol and pentamers in the case of ethanol. The content of big clusters in a liquid phase as predicted by QCE is overestimated. We have found two confirmations of this. First of all, the behaviour of the liquid water isobar clearly demonstrates that there should be a substantial amount of small clusters in order to obtain the correct temperature dependence of the molar volume. Indeed, the theoretical molar volume close to the boiling point is by about 0.6cm³ lower than the experimental one. The molar volume is too low due to the overestimated population of big clusters resulting in too high a liquid density. Second, the temperature dependence of the chemical shift of the hydroxyl protons in liquid methanol and ethanol, obtained as the population weighted average of the chemical shift of individual clusters, is shifted down field as compared to experiment by as much as 2ppm. This is because big clusters with strongly deshielded hydroxyl protons contribute too much to the weighted average. Possible shortcomings of the QCE approach are discussed.     

PHOTOSENSITIZATION BY ANTITUMORAGENTS–6. PRODUCTION OF SUPEROXIDE RADICAL AND HYDROGEN PEROXIDE DURING ILLUMINATION OF DIAMINOANTHRACENEDIONES IN THE PRESENCE OF NADH IN AQUEOUS SOLUTIONS: AN EPR STUDY

Abstract— Photosensitizing capabilities of anthracenedione anticancer agents to oxidize NADH in aqueous solutions have been studied by EPR and spin trapping techniques. It is demonstrated that 1,4-diamino substituted anthraquinones, like mitoxantrone and ametantrone, do not photosensitize NADH oxidation while 1,5- and l,8-bis[[(diethylamino)ethyl]amino]anthraquinones do, undergoing simultaneous one-electron reduction to their semiquinone radical forms upon illumination with visible light. In aerated aqueous solutions the reaction leads to the production of superoxide ion and hydrogen peroxide.     

Brueckner-type reference determinants in applications of coupled cluster methods to excited states

Model studies have been undertaken of the efficiency of single-reference state coupled cluster (SR-CC) methods defined in terms of several Brueckner type orbitals in applications to excited states of a predominately closed shell structure. The H4 model was used, which offers an easy way of representing any set of symmetry adapted orbitals together with the possibility of varying the degree of quasi-degeneracy of the states considered. Standard Brueckner orbitals (BOs) and orbitals generated in the projective and variational Brueckner CC (BCC) methods have been obtained and compared for the first time for excited states. Some attention has been paid to the stability of the BOs. Results of applying Brueckner-type and RHF orbitals in CCD, CCSD, and CCSDT calculations for excited states of rather strong degrees of quasi-degeneracy are presented. It is shown that in most cases proceeding from RHF orbitals to Brueckner-type orbitals results in an improvement in the accuracy of the SR-CC energies. Differences and similarities in the characteristics of Brueckner-type orbitals and SR-CC results for excited states and the ground state are identified and discussed.