Freeness of equivariant cohomology and mutants of compactified representations

We survey generalisations of the Chang-Skjelbred Lemma for integral coefficients. Moreover, we construct examples of manifolds with actions of tori of rank > 2 whose equivariant cohomology is torsion-free, but not free. This answers a question of Allday's. The "mutants" we construct are obtained from compactified representations and involve Hopf bundles in a crucial way.Comment: 11 pages; more details on the smooth structure of the mutants; other, minor change

Steenrod squares on conjugation spaces

We prove that the coefficients of the so-called conjugation equation for conjugation spaces in the sense of Hausmann-Holm-Puppe are completely determined by Steenrod squares. This generalises a result of V.A. Krasnov for certain complex algebraic varieties. It also leads to a generalisation of a formula given by Borel and Haefliger, thereby largely answering an old question of theirs in the affirmative.Comment: 4 page

Job shopping after vocational training? An empirical analysis of the transition from apprenticeship training to work

This econometric study deals with the question as to what extent apprentices after successfully completing their training stay with the firm where they have received their training and, if so, how long that job tenure holds. Determinants of both decisions can be seen from both the employer`s and the employee`s viewpoint. The firm is interested to employ this apprentices in order to collect the returns from its investment in their training which frequently is associated with net costs. On the other hand, the firm dismisses apprentices if training is viewed by the firm as a screening device or if apprentices are engaged in work for which, in terms of wages, they are too expensive afterwards. The young trained worker bases his or her decision to stay or to leave on considerations such as experimenting with several jobs ("job shopping"). The realization of such an experimenting may depend on the situation on the labour market. The empirical part uses individual employee data covering the time period 1980 to 1991 in West Germany and is based on a hazard rate model. --Training,Apprenticeship,Youth Unemployment,Matching

Activity-based detection of consumption of synthetic cannabinoids in authentic urine samples using a stable cannabinoid reporter system

Synthetic cannabinoids (SCs) continue to be the largest group of new psychoactive substances (NPS) monitored by the European Monitoring Center of Drugs and Drugs of Abuse (EMCDDA). The identification and subsequent prohibition of single SCs has driven clandestine chemists to produce analogues of increasing structural diversity, intended to evade legislation. That structural diversity, combined with the mostly unknown metabolic profiles of these new SCs, poses a big challenge for the conventional targeted analytical assays, as it is difficult to screen for "unknown" compounds. Therefore, an alternative screening method, not directly based on the structure but on the activity of the SC, may offer a solution for this problem. We generated stable CB1 and CB2 receptor activation assays based on functional complementation of a split NanoLuc luciferase and used these to test an expanded set of recent SCs (UR-144, XLR-11, and their thermal degradation products; AB-CHMINACA and ADB-CHMINACA) and their major phase I metabolites. By doing so, we demonstrate that several major metabolites of these SCs retain their activity at the cannabinoid receptors. These active metabolites may prolong the parent compound's psychotropic and physiological effects and may contribute to the toxicity profile. Utility of the generated stable cell systems as a first -line screening tool for SCs in urine was also demonstrated using a relatively large set of authentic urine samples. Our data indicate that the stable CB reporter assays detect CB receptor, activation by extracts of urine in which SCs (or their metabolites) are present at low- or subnanomolar (ng/mL) level. Hence, the developed assays do not only allow activity profiling of SCs and their metabolites, it may also serve as a screening tool, complementing targeted and untargeted analytical assays and preceding analytical (mass spectrometry based) confirmation