Cucurbit[7[uril, the wheel component in two new and structurally simple pseudorotaxanes, shuttles between the two axle termini at low pH, whereas the shuttling motion stops at higher pH, as the wheel is bound to the center of the axle.

In ontology-based data access, data are queried through an ontology that offers a representation of the domain of interest. In this context, correct answers are those entailed by the logical theory constituted by the data and the ontology. Traditional database constraints like tuple-generating dependencies (TGDs) and equality-generating dependencies (EGDs) are a useful tool for ontology specifi...

Schema mappings have been extensively studied in database research over the past decade – notably in the areas of data exchange and data integration. Recently, the notion of an information transfer order on schema mappings has been introduced to compare the amount of source information that is actually transferred by two mappings. In this paper, we present two new operators: the union and inter...

New techniques, both theoretical and practical, are presented for constructing permutation representations for computing with matrix groups defined over finite fields. The permutation representation is constructed on a conjugacy class of subgroups of prime order. We construct a base for the permutation representation, which in turn simplifies the computation of a strong generating set. In addit...

This paper deals with the problem of finding a base and strong generating set for the group generated by a given set of permutations. The concepts of base and strong generating set were introduced by Sims [5], [6] and provide the most effective tool for computing with permutation groups of high degree. One algorithm, originally proposed by Sims [7], is described in detail; its behavior on a num...

SGS is a compact sentence generation system. Inputs are the frames and specifications of a sentence. Programs attached to context free rules carry out the generation task. Output is a surface sentence with an associated derivation tree. suitable laws for a computer from lingistic phenomena. Therefore, this paper first describes the overall organization of SGS, secondly explains the linguistic s...

In this work we study numbers and polynomials generated by two type of composition of generating functions and get their explicit formulae. Furthermore we state an improvementof the composita formulae's given in [6] and [3], using the new composita formula's we construct a variety of combinatorics identities. This study go alone to dene new family of generalized Bernoulli polynomials which incl...

An algorithm due to Bengalloun that continuously enumerates the primes is adapted to give the rst prime number sieve that is simultaneously sublinear, additive, and smoothly incremental: { it employs only (n= log log n) additions of numbers of size O(n) to enumerate the primes up to n, equalling the performance of the fastest known algorithms for xed n; { the transition from n to n + 1 takes on...

Poor households worldwide rely on savings groups (SGs) to satisfy their financial needs, yet very little is known about these groups’ ability to meet them. In this paper we develop a theoretical model illustrating the basic trade-offs in the functioning of SGs, and present stylized facts derived from the financial accounts of a sample of Ugandan SGs. The main conclusion from the theoretical mod...