Daily rhythm of salivary IL-1ß, cortisol and melatonin in day and night workers

Shiftwork-induced sleep deprivation and circadian disruption probably leads to an increase in the production of cytokines and dysregulation of innate immune system, respectively. This project aims evaluating changes in salivary IL-1 beta, cortisol, and melatonin in night workers. Method. Two day and three night healthy workers participated in this study. Sleep was evaluated by actimetry and activity protocols. Saliva was collected at waking and bedtime the last workday and the following two days-off and was analyzed by ELISA. Results. Neither sleep duration nor efficiency showed any association with salivary IL-1beta. IL-1beta levels were higher at waking than at bedtime during working days for all workers, but only one day and one night-worker maintained this pattern and hormone rhythms during days off. For this night worker, melatonin levels were shifted to daytime. A second one presented clear alterations in IL-1beta and hormone rhythms on days-off. Conclusions. Our preliminary results suggest that night work can disturb the variation pattern of salivary IL-1beta. No association of this variation with sleep was observed. It seems that disruption in hormone rhythms interfere with salivary IL-1beta production. IL- 1beta production pattern seems to be maintained when rhythms are present, in spite of a shift in melatonin secretion.     

Was müssen Führungskräfte können?

Ethics Education complements business administration only if it teaches strategic competencies that help managers to become better leaders. To this end, this article sketches an ordonomic approach to an economic ethics for competitive markets, to a business ethics for firms (corporate citizens), and to a process ethics for new governance. The core idea of this ordonomic approach is the win-win concept of mutually beneficial value creation. Thus, ordonomics is compatible with the market economy and at the same time supplements the management education in business schools: This approach systematically identifies strategic competencies that enable managers to display the kind of entrepreneurial leadership that is necessary for firms to fulfill their social function of value creation—by making use of moral commitments as a factor of production.     

On threshold BDDs and the optimal variable ordering problem

Many combinatorial optimization problems can be formulated as 0/1 integer programs (0/1 IPs). The investigation of the structure of these problems raises the following tasks: count or enumerate the feasible solutions and find an optimal solution according to a given linear objective function. All these tasks can be accomplished using binary decision diagrams (BDDs), a very popular and effective datastructure in computational logics and hardware verification. We present a novel approach for these tasks which consists of an output-sensitive algorithm for building a BDD for a linear constraint (a so-called threshold BDD) and a parallel AND operation on threshold BDDs. In particular our algorithm is capable of solving knapsack problems, subset sum problems and multidimensional knapsack problems. BDDs are represented as a directed acyclic graph. The size of a BDD is the number of nodes of its graph. It heavily depends on the chosen variable ordering. Finding the optimal variable ordering is an NP-hard problem. We derive a 0/1 IP for finding an optimal variable ordering of a threshold BDD. This 0/1 IP formulation provides the basis for the computation of the variable ordering spectrum of a threshold function. We introduce our new tool azove 2.0 as an enhancement to azove 1.1 which is a tool for counting and enumerating 0/1 points. Computational results on benchmarks from the literature show the strength of our new method.     

Overviewing the transition of Markowitz bi-criterion portfolio selection to tri-criterion portfolio selection

Over 60 years ago, Markowitz introduced the mean-variance efficient frontier to finance. While mean-variance is still the predominant model in portfolio selection, it has endured many criticisms. One serious one is that it does not allow for additional criteria. The difficulty is that the efficient frontier becomes a surface. With it now possible to compute such a surface, we provide an overview on how Markowitz’s risk-return (bi-criterion) portfolio selection can be extended to tri-criterion portfolio selection. With a focus on the geometry of the extension, many graphs are used to illustrate.     

Looks and Labor: Do Attractive People Work More?

Using the German General Social Survey (ALLBUS) 2008, I investigate how looks affect an individual's labor supply decision. My results are, by and large, in line with predictions derived from the neoclassical model of labor supply. Applying regular probit, bivariate probit, Tobit and Heckman selection regression models, I find that good looks go hand in hand with higher employment probabilities and more hours of market work. Furthermore, physical attractiveness is positively associated with spousal income and spousal employment. Hence, beauty appears to affect labor supply decisions both directly and through the marriage market.     

Mein(schöner)Prof.de

Evaluations of academic teaching have become an instrument for the quality management in universities of constantly growing importance. This process is unproblematic as long as the quality of teaching is rated validly by the evaluations of students. The validity of the rating, however, becomes questionable as an influence of the teaching staffs’ physical attractiveness on the evaluation of teaching has been proved. This effect would only be compatible with an assumed valid rating of the teaching performance if attractive teachers would in fact show a better performance in academic teaching and are not just better rated for their attractiveness. We analyzed data from the German online platform MeinProf.de for the evaluation of academic teachers. The results show that attractive teachers very probably do not perform better. The attractiveness of female teachers does not have the expected influence on the evaluation of their teaching.     

Trajectories of body mass and self-concept in black and white girls: the lingering effects of stigma

As a stigmatizing condition, obesity may lead to the internalization of devalued labels and threats to self-concept. Modified labeling theory suggests that the effects of stigma may outlive direct manifestations of the discredited characteristic itself. This article considers whether obesity's effects on self-concept linger when obese youth enter the normal body mass range. Using longitudinal data from the National Growth and Health Study on 2,206 black and white girls, we estimated a parallel-process growth mixture model of body mass linked to growth models of body image discrepancy and self-esteem. We found that discrepancy was higher and self-esteem lower in formerly obese girls compared to girls always in the normal range and comparable to chronically obese girls. Neither body image discrepancy nor self-esteem rebounded in white girls despite reduction in body mass, suggesting that the effects of stigma linger. Self-esteem, but not discrepancy, did rebound in black girls.