Etude de la réaction de l'acétylacétone avec les diamines hétéroaromatiques

The inluence of the starting o-diamine on the reaction products is shown in the condensation of heteroaromatic o-diamines with acetylacetone; 2,3- and 3,4-diaminopyridines gave only a crotonic intermediate providing imidazopyridines. On the other hand, 1,5-diaminoimidazoles gave tow types of compounds, imidazotriazepines and imidazopyridines. Triazolopyridazines were formed from 3,4-diaminotriazoles.     

Gamma-ray spectroscopy with relativistic exotic heavy-ions

Feasibility of gamma-ray spectroscopy at relativistic energies with exotic heavy-ions and new generation of germanium detectors (segmented Clover) is discussed. An experiment with such detector array and radioactive is discussed.     

A Modification of an Algorithm by Golub and Plemmons for Large Linear Least Squares in the Context of Doppler Positioning

This paper considers the solution of the geodetic Doppler multi-stationadjustment, i.e. the problem of computing the positions of severalstations observing the Doppler shift on radio frequencies emittedby several artificial satellites passing over the horizon. Amodification of an algorithm due to Golub and Plemmons, forsolving large linear least-squares problems where the observationmatrix has a block dual angular form, is proposed in this framework.This modification is shown to reduce substantially both datatransfer between the tracking stations and the main computingcentre, and the total computational effort required to obtainthe solution of the problem. Preliminary numerical results arediscussed and some further comments presented.     

From Stochastics to Complexity in Models of Economic Instability

Sixty years ago, the leading lights of the economics profession chose to model economic fluctuations as if they were caused by stochastic disturbances to an underlying stable, heavily damped system, in the mistaken belief that a mathematically unstable system does not fluctuate; it just breaks down. A perceptive minority instead concluded that the fundamental relations in economics must be nonlinear. It is shown that a single sector model with nonlinear behavior by workers, capitalists and the government generates a chaotic explanation for the most extreme of economic fluctuations, a Great Depression. A multi-sectoral model of a stylized economy confirms the judgment that economics is fundamentally a nonlinear discipline, by establishing that the input-output nature of production generates substantive nonlinearities, even when linear behavioral functions are assumed.     

Effect of Motif‐Programmed Artificial Proteins on the Calcium Uptake in a Synthetic Hydrogel

Motif‐programmed artificial proteins with mineralization‐related activity were covalently immobilized onto the surface of a hydrogel, poly(2‐hydroxyethyl methacrylate) (PHEMA). We investigated the influence of assaying conditions upon the ability of three selected proteins (PS64, PS382 and PS458) to modulate calcification in vitro. A long‐term assay measuring the real amount of calcium phosphate phase in the protein‐modified PHEMA showed that all proteins enhanced the uptake of calcium by the hydrogel. For PS382 and PS458, this is a behaviour opposite to that displayed when the same proteins were tested in a free state by a rapid solution assay. Such difference may be attributed to a restricted mobility of the proteins due to immobilization.

     

Facile assembly of a Cu9 amido complex: a new tripodal ligand design that promotes transition metal cluster formation

A tripodal amido ligand with a central non-chelating phosphorus donor allows for the facile assembly of a pentane soluble organometallic copper cluster with a central copper atom surrounded by a nonplanar chain of eight copper atoms and two terminal amido-copper bonds.