On pairs of free modules over a Dedekind domain

The study of pairs of modules (over a Dedekind domain) arises from two different perspectives, as a starting step in the analysis of tuples of submodules of a given module, or also as a particular case in the analysis of Abelian structures made by two modules and a morphism between them. We discuss how these two perspectives converge to pairs of modules, and we follow the latter one to obtain an alternative approach to the classification of pairs of torsionfree objects. Then we restrict our attention to pairs of free modules. Our main results are that the theory of pairs of free Abelian groups is co-recursively enumerable, and that a few remarkable extensions of this theory are decidable. Work performed under the auspices of GNSAGA-INDAM     

Voltammetric Detection of Free Sulfhydryl Compounds in Food Flours

Cyclic voltammetry has been applied to the rapid measurement of free SH‐compounds in food flours samples. The protocol is based on the electrochemical adaptation of the Ellman's test, where the DTNB reacts with SH‐compounds present in food flour extracts, resulting in the equimolar production of the electroactive compound TNBA which, in turns, reacts with phenylendiamine. The reaction is found to provide an analytical signal from which to quantify indirectly free sulfhydryl compounds in flours extracts.     

Computational spectroscopy of helium-solvated molecules: effective inertia, from small He clusters toward the nanodroplet regime

Accurate computer simulations of the rotational dynamics of linear molecules solvated in He clusters indicate that the large-size (nanodroplet) regime is attained quickly for light rotors (HCN) and slowly for heavy ones (OCS, N2O, and CO2), thus challenging previously reported results. Those results spurred the view that the different behavior of light rotors with respect to heavy ones-including a smaller reduction of inertia upon solvation of the former-would result from the lack of adiabatic following of the He density upon molecular rotation. We have performed computer experiments in which the rotational dynamics of OCS and HCN molecules was simulated using a fictitious inertia appropriate to the other molecule. These experiments indicate that the approach to the nanodroplet regime, as well as the reduction of the molecular inertia upon solvation, is determined by the anistropy of the potential, more than by the molecular weight. Our findings are in agreement with recent infrared and/or microwave experimental data which, however, are not yet totally conclusive by themselves.     

Rotational dynamics of CO solvated in small He clusters: a quantum Monte Carlo study

The rotational dynamics of CO single molecules solvated in small He clusters (CO @ HeN) has been studied using reptation quantum Monte Carlo simulations for cluster sizes up to N = 30. Our results are in good agreement with the rotovibrational features of the infrared spectrum recently determined for this system and provide a deep insight into the relation between the structure of the cluster and its dynamics. Simulations for large N also provide a prediction of the effective moment of inertia of CO in the He nanodroplet regime, which has not been measured so far.