Using selected theoretical methods the affinity of a large range of Lewis bases towards model cations has been quantified. The range of model cations includes the methyl cation as the smallest carbon-centered electrophile, the benzhydryl and trityl cations as models for electrophilic substrates encountered in Lewis base-catalyzed synthetic procedures, and the acetyl cation as a substrate model ...

This paper describes several classical constructions of thin bases of finite order in additive number theory, and, in particular, gives a complete presentation of a beautiful construction of J. W. S. Cassels of a class of polynomially asymptotic bases. Some open problems are also discussed. 1. Additive bases of finite order The fundamental object in additive number theory is the sumset. If h ≥ ...

In this paper we present an overview of knowledge-based systems. We begin by discussing the basic characteristics of knowledge base rules and present an example comparing a toy knowledge base to an equivalent procedural version of the same code. We then discuss the applications for which it makes sense to use knowledge-based technology and the advantages offered by reuse of a general-purpose up...

Nephrogenic systemic fibrosis (NSF), first described in 2000 in a 15-patient case series, is an extremely debilitating, multisystemic fibrosing disorder. Since that initial report, more than 300 cases have been recognized, and their histopathologic features have been categorized. Two known associations with NSF are renal dysfunction and exposure to gadolinium (Gd)– containing magnetic resonance...

In the thesis we have investigated the complexity of proofs in several propositional proof systems. Our main motivation has been to contribute to the line of research started by Cook and Reckhow to obtain how much knowledge as possible about the complexity of di erent proof systems to show that there is no super proof system. We also have been motivated by more applied questions concerning the ...

In a previous article [35] an algebraicity result for the central critical value for L-functions for GLn × GLn−1 over Q was proved assuming the validity of a nonvanishing hypothesis involving archimedean integrals. The purpose of this article is to generalize [35, Thm. 1.1] for all critical values for L-functions for GLn×GLn−1 over any number field F while using the period relations of [37] and...