Formylation of easily accessible heteroarylacetic acids (R-CH2COOH, R = imidazole, pyrazole, tetrazole, pyridine) afforded in high yields the corresponding trimethinium salts R-C(=CH-N(CH3)2)CH=N(CH3)2)n+ nX- which on alkaline hydrolysis were converted into N-diformylmethylazoles R-C(CHO)=CH-OH. Their quaternization gave cycloimonium diformyl methylides.
We show that adiabatic, super-Hubble, and almost scale invariant density fluctuations are produced by cosmic strings in a contracting universe. An essential point is that isocurvature perturbations produced by topological defects such as cosmic strings on super-Hubble scales lead to a source term which seeds the growth of curvature fluctuations on these scales. Once the symmetry has been restored at high temperatures, the isocurvature seeds disappear, and the fluctuations evolve as adiabatic ones in the expanding phase. Thus, cosmic strings may be resurrected as a mechanism for generating the primordial density fluctuations observed today.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.