An effect of silicon substitution remote from reactive site

The source of a rate retardation of the trimethylsilyl substituent in an alkylation reaction is probed.     

A quantum mechanical twin paradox

When a quantummechanical wavepacket undergoes a series of Galilean boosts, the Schrödinger theory predicts the occurrence of a geometrical phase effect that is an example of Berry's phase (Sagnac's phase). In the present paper the conceptual consequences of this phenomenon are considered, in particular for the status of Galilean invariance in nonrelativistic quantum mechanics, and for the relation between that theory and classical physics.     

New molecular entities via intermolecular meta photocycloaddition

The intermolecular meta photocycloaddition of 1,3‐dihydroisobenzofuran and 1,3‐dihydroisoindole‐2‐carboxylic acid methyl ester with cyclopentene and 2,5‐dihydrofuran affords two new classes of photoadducts. The photoadducts were identified by the SORT&gen algorithm as New Molecular Entities in two‐dimensional scaffold space. The structures of the adducts were established by NMR spectroscopy and the stereo‐, regio‐ and chemoselectivity of the reactions is discussed.     

Clark's theorem for semi-infinite convex programs

In 1961, Clark proved that if either the feasible region of a linear program or its dual is nonempty and bounded, then the other is unbounded. Recently, Duffin has extended this result to a convex program and its Lagrangian dual. Moreover, Duffin showed that under this boundedness assumption there is no duality gap. The purpose of this paper is to extend Duffin's results to semi-infinite programs.     

Supersymmetry-breaking through D-terms

Models in which supersymmetry is broken by the Fayet-Iliopoulos mechanism are reconsidered. The possibility that scalar quark and lepton masses might arise radiatively in such theories is explored. It is shown that in several interesting cases, these masses-squared are all negative. In grand-unified versions of these models, it is shown that the scale of SU(2) × U(1) breaking tends to be much larger than the scalar quark and lepton masses, i.e. that the hierarchy is unstable.