Infinite graphic matroids Part I

An infinite matroid is graphic if all of its finite minors are graphic and the intersection of any circuit with any cocircuit is finite. We show that a matroid is graphic if and only if it can be represented by a graph-like topological space: that is, a graph-like space in the sense of Thomassen and Vella. This extends Tutte's characterization of finite graphic matroids. The representation we construct has many pleasant topological properties. Working in the representing space, we prove that any circuit in a 3-connected graphic matroid is countable

Income support policies for part-time workers : a stepping-stone to regular jobs ? An application to young long-terme unemployed women in Belgium

We verify whether an income support policy for part-time workers in Belgium increases the transition from unemployment to non-subsidised, “regular” employment. Using a sample of 8630 long-term unemployed young women, whose labour market history is observed from 1998 to 2001, we implement the “timing of events approach proposed byAbbring et Van den Berg (2003) to control for selection effects. Our results suggest that the policy has a significantly positive effect on the transition to non-subsidised employment when one does not control for unobserved heterogeneity. This effect remains positive, but becomes insignificant, when one corrects for selection on unobservable characteristics.Active labour markets policies, Evaluation, Mixed Proportional Hazard Models

Impact of Interatomic Electronic Decay Processes on Xe 4d Hole Decay in the Xenon Fluorides

A hole in a 4d orbital of atomic xenon relaxes through Auger decay after a lifetime of 3 fs. Adding electronegative fluorine ligands to form xenon fluoride molecules, results in withdrawal of valence-electron density from Xe. Thus, within the one-center picture of Auger decay, a lowered Xe 4d Auger width would be expected, in contradiction, however, with experiment. Employing extensive ab initio calculations within the framework of many-body Green's functions, we determine all available decay channels in XeFn and characterize these channels by means of a two-hole population analysis. We derive a relation between two-hole population numbers and partial Auger widths. On this basis, interatomic electronic decay processes are demonstrated to be so strong in the xenon fluorides that they overcompensate the reduction in intra-atomic Auger width and lead to the experimentally observed trend. The nature of the relevant processes is discussed. These processes presumably underlie Auger decay in a variety of systems.Comment: 11 pages, 5 figures, 3 tables, RevTeX4, extensively revised, the discussion of single ionization of XeFn was published separately: J. Chem. Phys. 119, 7763--7771 (2003), preprint arXiv: physics/030612

Digital maturity variables and their impact on the enterprise architecture layers

This study examines the variables of digital maturity of companies. The framework for enterprise architectures Archimate 3.0 is used to compare the variables. The variables are assigned to the six layers of architecture: Strategy, Business Environment, Applications, Technology, Physical and Implementation and Migration. On the basis of a literature overview, 15 “digital maturity models” with a total of 147 variables are analyzed. The databases Scopus, EBSCO – Business Source Premier and ProQuest are used for this purpose