Monitoring means and covariances of multivariate non linear time series with heavy tails

In this paper, the focus is on sequential analysis of multivariate financial time series with heavy tails. The mean vector and the covariance matrix of multivariate non linear models are simultaneously monitored by modifying conventional control charts to identify structural changes in the data. The considered target process is a constant conditional correlation model (cf. Bollerslev, 1990 Bollerslev, T. (1990). Modeling the coherence in short-run nominal exchange rates: A multivariate generalized ARCH model. Rev. Econ. Stat. 72:498–505.[Crossref], [Web of Science ®] , [Google Scholar]), an extended constant conditional correlation model (cf. He and Teräsvirta, 2004 He, C., Teräsvirta, T. (2004). An extended constant conditional correlation GARCH model and its fourth-moment structure. Economet. Theory 20:904–926.[Crossref], [Web of Science ®] , [Google Scholar]), a dynamic conditional correlation model (cf. Engle, 2002 Engle, R.F. (2002). Dynamic conditional correlation: A simple class of multivariate GARCH models. J. Bus. Econ. Stat. 20(3):339–350.[Taylor &; Francis Online], [Web of Science ®] , [Google Scholar]), or a generalized dynamic conditional correlation model (cf. Capiello et al., 2006 Capiello, L., Engle, R., Sheppard, K. (2006). Asymmetric correlations in the dynamics of global equity and bond returns. J. Financial Economet. 4(4):537–572.[Crossref] , [Google Scholar]). For statistical surveillance we use control charts based on residuals. Further, the procedures are constructed for t-distribution. The detection speed of these charts is compared via Monte Carlo simulation. In the empirical study, the procedure with the best performance is applied to log-returns of the stock market indices FTSE and CAC.     

Activation,Public Employment Services and their Clients: The Role of Social Class in a Continental Welfare State

This article fills a gap in the existing literature by investigating how public employment service (PES) staff actually deal with their clients under a continental regime of activation. The results reported here are based on interviews both with PES staff and their unemployed clients in Germany. We argue that due to its Bismarckian origins as an insurance‐based system of ‘unemployment protection’, Germany's system of unemployment compensation is attractive not only for the marginalized, but also for core workers. As a result, PES staff deal with clients from very heterogeneous class backgrounds. We demonstrate that social class is a significant factor in client outcomes, and that earlier research has perhaps overemphasized the role of frontline staff as ‘street‐level bureaucrats’. While staff do have considerable power, the result of the encounters between the administration and clients also depends on the capabilities of the clients, which, in turn, are strongly related to social class.     

In Conclusion: Current Themes in Bereavement and Widowhood Research

A number of important themes and controversies emerged from the preceding papers. These include (a) what kinds of losses lead to grief; (b) how long grief lasts; (c) how to conceptualize "recovery," (d) the nature of "normal" grief; (e) whether bereavement has lasting effects on health; and (f) what characteristics of the individual, the relationship, or the nature of the death create a greater risk for poor outcome of bereavement. Consideration of these issues should help develop more effective strategies for intervention with sufferers, and social policies sensitive to the needs of those at greatest risk.     

Mean-variance portfolios using Bayesian vector-autoregressive forcasts

Protfolio optimization is very sensitive to the forecats of returns and (co-)variances of the underlying assets. This paper applies a Bayesian vector-autoregression of the asset universe to predict the returns. Further, the co-variance matrix is forecasted by an Augmented GARCH estimation of the most volatile principle components of the return series. As an empirical illustration, the daily stock returns of the German stocks index DAX have been used to calculate some well-known mean-variance portfolios. Back-testing is used to evaluate the performance. The approach seems to be promising.     

Das Feuer kleiner Gruppen: Analyse der Entwicklungslogik und -dynamik eines Beratungsprozesses

The spark of small groups: An analysis of the developmental logic and dynamics of a consultancy process In the recent past large group interventions have gained increased attention in the systemic consulting literature. In contrast to this tendency, this paper focuses on the significance and effectiveness of small group interventions in business consultancy.Based on a qualitative analysis of a consultancy process, the effectiveness of small group change processes is documented here: Unlike large groups, small groups not only are far more likely to succeed in developing structures which differ from the existing organizational structures, they moreover are much more likely to develop a strong identity which helps them generate the power necessary for change. Especially in conflict situations and in situations where the pressures that are being put on an organization are increasing, small groups are more likely to maintain their identity, another crucial prerequisite for the initiation of a change process.The paper shows that consultancy systems, which differ in structure from the customer organization, are apt to serve as incubators for the development of strong groups within an organization. These small groups are able to push for organizational changes using conflicts process.