New critical dimensions forq-deformed bosonic string

Applying the mass shell condition forq-deformed open and closed strings, new critical space-time dimensions are derived. Supported by the Algerian Ministry of High Education and Research under contract N^oD2501/17/01/93. Permanent address.     

Counting and enumeration complexity with application to multicriteria scheduling

In this paper we tackle an important point of combinatorial optimisation: that of complexity theory when dealing with the counting or enumeration of optimal solutions. Complexity theory has been initially designed for decision problems and evolved over the years, for instance, to tackle particular features in optimisation problems. It has also evolved, more or less recently, towards the complexity of counting and enumeration problems and several complexity classes, which we review in this paper, have emerged in the literature. This kind of problems makes sense, notably, in the case of multicriteria optimisation where the aim is often to enumerate the set of the so-called Pareto optima. In the second part of this paper we review the complexity of multicriteria scheduling problems in the light of the previous complexity results.Received: November 2004 / Received version: March 2005MSC classification: 90B40, 90C29, 68Q15     

Aq-deformed left-right symmetric model

A newq-deformed Left-Right Symmetric model is constructed and the various mass relations and mixing angles are derived. It is shown that the model allows for parity violation, and predicts a new Z’ gauge boson.     

Acid promoted enantioselective oxygen-atom transfer from N-alkyl binaphthyl-derived oxaziridines onto sulfides

Acid-promoted asymmetric sulfoxidations of prochiral sulfides using binaphthyl-derived oxaziridines have been studied. The reactions of dialkyl or aryl-alkyl sulfides gave good yields of the corresponding sulfoxides with enantiopurities ranging from 20% to 80%. The influence of temperature and strength of the acid catalyst on enantioselectivity was studied. The absolute configuration of the resulting major enantiomer varied with the structure of the sulfide.     

Theq-deformed virasoro algebra

Theq-deformed Virasoro algebra is studied in the context of the string theory. It is shown that the anomaly term is not ac-number and depends strongly on the deformation parameterq. Supported by the Algerian Ministry of High Education and Research under contract N^oD2501/17/01/93. Permanent address     

Multiple Unbounded Positive Solutions for Three-Point BVPs with Sign-Changing Nonlinearities on the Positive Half-Line

This work is concerned with the existence of unbounded positive solutions for a second-order nonlinear three-point boundary value problem on the positive half-line. The interesting points of the results are that the nonlinearity depends on the solution and its derivative and may change sign. Moreover, it satisfies general polynomial growth conditions. New existence results of nontrivial single and multiple positive solutions are proved using recent fixed point theorems on cones in a special Banach space.     

Price competition and store competition: Store brands vs. national brand

This paper studies pricing strategies in a market channel composed of one national brand manufacturer and two retailers who, each, carry their own store brand and a national brand products. The model accounts for product competition between store brands and the national brand products, as well as for store competition between retailers.     

A microwave-assisted and heteropolyacids-catalysed cyclocondensation reaction for the synthesis of 4(3H)-quinazolinones

We have investigated a microwave-assisted synthesis of 4(3H)-quinazolinones by condensation of anthranilic acid, orthoesters (or formic acid) and substituted anilines,using Keggin-type heteropolyacids (H(3)PW(12)O(40).13H(2)O, H(4)SiW(12)O(40).13H(2)O,H(4)SiMo(12)O(40).13H(2)O or H(3)PMo(12)O(40).13H(2)O) as catalysts. We found that the the use of H(3)PW(12)O(40).13H(2)O acid coupled to microwave irradiation allows a solvent-free, rapid (approximately 13min) and high-yielding reaction.     

On uniqueness and existence of entropy solutions for a nonlinear parabolic problem with absorption

The aim of this paper is to study, for L ¹-data, the absorption problem of parabolic type : with Dirichlet boundary conditions and initial conditions. Here a satisfies the classical Leray-Lions hypotheses and β(x, ·) is the subdifferential ∂j(x, ·), where j is a convex function such that j(·, 0) = 0. Existence and uniqueness of an entropy solution is established.