Auf den Rangplatz kommt es an – Wirkung der Rangfolge von Produkten auf das Entscheidungsverhalten

Customers often search for and choose from ordered sets. E. g., online shops present their product assortments as lists; very often the products are listed according to criteria as defined by the customers. Based on theoretical explanations it can be assumed that the rank of a product in a list effects its demand. An empirical study run in the market for used cars shows the importance of that effect. The study also reveals the most preferred rank and provides further insights for an optimal ordering of products. Furthermore, the understanding of individual decision about rank ordered products can be deepened.     

Estimating turnover,movements and capture parameters of resting passerines in standardized capture-recapture studies

Jolly-Seber models A, B, D and 2 were used to investigate capture-recapture data. The standard Jolly-Seber model A (time-dependent survival phi and capture probability p ) fits capture-recapture data of migrating passerines. Captures from a long-term mist-netting study (Mettnau Peninsula, SW Germany) at a stop-over site were used to estimate stop-over length from survival rate between days and capture probability. For some data, model 2 could be used, indicating a termporary reduction in 'survival' rate. Application of models B and D gave poor results. The total number of birds stopping over, i.e. population size, was estimated from captures of 1-5 line transects of nets in the spatial trapping design. Behaviour, movements within the stop-over site, catchability and ecophysiological covariables such as moult, fat deposition and climatic parameters are likely to have strong influence on the estimation of capture parameters.     

Pensions as a portfolio problem: fixed contribution rates vs. fixed replacement rates reconsidered

Pay-as-you-go (PAYG) pension schemes can contribute to better intergenerational risk-sharing and diversification. However, different variants of PAYG schemes entail different properties in these respects. In a stochastic 2-OLG model we compare PAYG schemes with fixed contribution rates and such with fixed replacement rates. The literature has shown that the former are preferable to the later from an ex ante perspective. We derive the opposite result for the ex post perspective. Here, schemes with fixed replacement rates are unambiguously preferable: they enhance intergenerational risk-sharing, lead to a higher savings and higher utility levels. We further show that, from an ex ante (veil-of-ignorance), perspective both schemes are non-comparable if the effect that fixed-replacement schemes serve as an insurance device for old-age income is properly accounted for. Received: 7 December 2000/Accepted: 17 May 2001     

Perzeption, Interaktion und die Ökologie der Gesellschaft — eine systemtheoretische Suche nach den Sinnen

This paper is an attempt to analyze the senses from a sociological perspective and within the context of Niklas Luhmann’s reflexive theory of social systems. A functional specification of the persceptive senses for the constitution and structuring of social systems will be achieved by means of the basic distinctions of system/environment, consciousness/communication, and interaction/society. Essentially, four levels can be distinguished with regard to perception, consciousness, and communication: 1) reflexive sensory perception of perceptions, 2) sensory perception of communication, 3) sensory perception due to communication, 4) communication based on purposefully initiated perception. As a result, the senses can be understood, on the one hand, as an infrastructural resource of communication and an ecological condition of society; on the other hand, they are themselves a binding, immanent structural principle of the social, or, more precisely, of interactions.     

Changes in the association between job decision latitude and work engagement at different levels of work experience: A 10-year longitudinal study

ABSTRACT

This study set out to explore the effects of accumulating work experience on the association between job decision latitude and its interaction with job demands and work engagement. Our ten-year longitudinal study followed 333 junior physicians in postgraduate training at baseline. We used self-report measures in four assessment waves, and we conducted path analyses to investigate linear and curvilinear regression effects. Results show that high job decision latitude was associated with high work engagement at all levels of work experience, with strongest associations at baseline and after ten years. Only for novices did job decision latitude buffer the negative association between job demands and work engagement. At the stage of high work experience, low levels of job decision latitude were weakly associated with work engagement, whereas with higher levels of job decision latitude, the positive association seemed to strengthen. Our findings indicate that job decision latitude is a key job resource at all stages of work experience, with stronger effects among novices and experts. Organisations’ work design efforts should include job decision latitude to promote work engagement across employees’ different career stages, with consideration to job entrants and experts in order to tailor specific work design solutions.     

Improved Bounds on Relaxations of a Parallel Machine Scheduling Problem

We consider the problem of scheduling n jobs withrelease dates on m identical parallel machines to minimize the average completion time of the jobs. We prove that the ratio of the average completion time of the optimal nonpreemptive schedule to that of the optimal preemptive schedule is at most 7/3, improving a bound of Shmoys and Wein.     

Collective action and network change

Network models of collective action commonly assume fixed social networks in which ties influence participation through social rewards. This implies that only certain ties are beneficial from the view of individual actors. Accordingly, in this study we allow that actors strategically revise their relations. Moreover, in our model actors also take into account possible network consequences in their participation choices. To handle the interrelatedness of networks and participation, we introduce new equilibrium concepts. Our equilibrium analysis suggests that structures that tend to segregate contributors from free riders are stable, but costless network change only promotes all-or-nothing participation and complete networks.     

Die Projektpolis bei der Arbeit. Open-Source-Software-Entwicklung und der „neue Geist des Kapitalismus“

The paper investigates the implementation of normative aspects in open source development projects. Current social analysis on open source tends to neglect the question how normative dispositions are enacted there in favor of a somewhat functionalist belief in the co-ordination mechanisms of gift economies or hacker ethics. In this paper, the “justificatory regime of projects“ developed by Boltanski and Chiapello is used as a blueprint of the normative order of knowledge-intensive contexts of collaboration. The notion of a “test” provides a micro-macro link in order to investigate the enactment of justifactory regimes in situated action. The paper identifies exemplary tests and critical incidents in two large open source projects, Debian and KDE. The justificatory regime of projects “at work” is found to be more complex and contradictory than the simple mechanisms of gift or knowledge economies would suggest. Their moral economy is not automatically integrated by a comprehensive “hacker ethic” of limitless involvement, technical excellence and fun. Projects, in their conflicts and discussions over norms, handle flexible involvements and the limitations of time and attention, and their normative regimes only work because they are able to manage that.