Risk of Extreme Events Under Nonstationary Conditions

The concept of the return period is widely used in the analysis of the risk of extreme events and in engineering design. For example, a levee can be designed to protect against the 100-year flood, the flood which on average occurs once in 100 years. Use of the return period typically assumes that the probability of occurrence of an extreme event in the current or any future year is the same. However, there is evidence that potential climate change may affect the probabilities of some extreme events such as floods and droughts. In turn, this would affect the level of protection provided by the current infrastructure. For an engineering project, the risk of an extreme event in a future year could greatly exceed the average annual risk over the design life of the project. An equivalent definition of the return period under stationary conditions is the expected waiting time before failure. This paper examines how this definition can be adapted to nonstationary conditions. Designers of flood control projects should be aware that alternative definitions of the return period imply different risk under nonstationary conditions. The statistics of extremes and extreme value distributions are useful to examine extreme event risk. This paper uses a Gumbel Type I distribution to model the probability of failure under nonstationary conditions. The probability of an extreme event under nonstationary conditions depends on the rate of change of the parameters of the underlying distribution.     

Implicit theories in organizational settings: A systematic review and research agenda of implicit leadership and followership theories

Implicit theories play important roles in many areas of human life. In this review, we focus on implicit leadership and followership theories, i.e. implicit assumptions of (good) leaders and followers, respectively. We provide a framework for categorizing the existing research in this field. We use this framework to show the current state of research and to illustrate the gaps in the literature. More precisely, we review which types of prototypes of leaders and followers have been studied, the effects of comparisons between the actual leader (respectively follower) with these activated prototypes as well as the contextual factors that influence prototype activation and prototype fit. We conclude by outlining implications for human resource management and for future research, thereby focusing on research questions that can be used to integrate the distinct paths in implicit leadership and followership theories.     

Economic crisis and the employee: The effects of economic crisis on employee job satisfaction,commitment, and self-regulation

Greece has been suffering a severe crisis starting in about 2009. This paper examines the impact of the recent economic crisis in Greece on employee work-related attitudes via changes in regulatory focus. We collected data in a large and heterogeneous sample of employees (N = 1024) during the crisis and compared them with a matched sample of employees surveyed (N = 882) half a decade earlier, i.e., before the crisis. Participants reported their job satisfaction, organizational commitment and their self-regulatory focus. Results show, as expected, that participants after start of the crisis were lower in extrinsic job satisfaction, affective organizational commitment and were also (unexpectedly) lower in normative commitment, while these attitudinal changes were explained by decreased promotion orientation and increased prevention focus. Rather unexpectedly, pre-crisis and crisis samples did not differ in levels of continuance commitment. This paper makes a relevant contribution by showing that the threatening crisis event does not only have negative effects on work-related outcomes, but also that changes in regulatory foci occur and explain attitudinal change indicating an adaptive mechanism to the threatening situation of an economic crisis.     

An extension of Monte Carlo hypothesis tests

There are many hypothesis testing settings in which one can calculate a “reasonable” test statistic, but in which the null distribution of the statistic is unknown or completely intractable. Fortunately, in many such situations, it is possible to simulate values of the test statistic under the null hypothesis, in which case one can conduct a Monte Carlo test. A difficulty however arises in that Monte Carlo tests, as they are currently structured, are applicable only if ties cannot occur among the values of the test statistics. There is a frequently occurring scenario in which there are lots of ties, namely that in which the null distribution of the test statistic has a (single) point mass. It turns out that one can modify the current form of Monte Carlo tests so as to accommodate such settings. Developing this modification leads to an intriguing identity involving the binomial probability function and its derivatives. In this article, we will briefly explain the modified procedure, discuss simulation studies which demonstrate its efficacy, and provide a proof of the identity referred to above.     

Social inequality of reading literacy: A longitudinal analysis with cross-sectional data of PIRLS 2001 and PISA 2000 utilizing the pair wise matching procedure

In accordance to Boudon's structural-individualistic action model, it is the aim of this paper to investigate the casual effects of individual abilities, resources of the parental home, socially selective educational transitions as well as teaching and learning conditions in schools on the development of reading literacy and its dispersion in respect of social origin. It is assumed that the socially selective transition into the secondary school tracks contributes to the general deterioration of the mean reading literacy when controlling for social origin and individual achievement. The socially selective transition from primary to secondary school contributes to the increase of social inequality of reading literacy existing already since the start of the pupils’ schooling. Since it is not possible to isolate these causes with comparative-static cross-sectional data like PIRLS or PISA empirically, we use a design of generating quasi-longitudinal data with three time references, namely reading literacy at the point of enrolment into elementary school, at the age of 9–10 years, and at the age of 15 years by the pair wise matching of “synthetic twins” with identical status criteria. The empirical analysis of the German data of PISA 2000 and PIRLS 2001 confirm the effects of the individual abilities depending on social origin, the social selectivity of transition into the secondary schools, the sorting and selection performances of the school system, the allocation of children into different learning contexts, and the schooling of both the individual development of reading competences and the social inequality of reading literacy.     

Method inventory for assessment of physical activity at VDU workplaces

Physical inactivity and prolonged static work tasks may seriously affect health. There are numerous indications that promoting physical activity (PA) at sedentary workplaces can reduce these health risks. However, PA interventions have so far been documented rarely on the basis of medical parameters. Effects on the PA behavior are often studied only through the methods of subjective self-assessment. For this reason an extensive method inventory was developed consisting of objective PA assessment methods and various methods for documenting PA related health outcomes. The developed method inventory has been tested in a pilot intervention study at office workplaces. The current paper presents and discusses a part of the applied inventory. The methods considered here demonstrated several positive intervention effects: intervention subjects were more active, felt better, increased muscle strength and showed improvements in resting heart rate and BMI. Not all data has been analyzed to date, but the preliminary results suggest that most of the investigated methods turned out to be suitable for the documentation of intervention effects. Among the methods for which no effects were found, the question remains whether this is due to a lack of sensitivity of the method or due to aspects related to the study design.     

What changes during specialized foster care? A study on adaptive functioning and emotional and social problems

Various models of specialized foster care have been developed, but research on them is limited. This longitudinal, exploratory study analysed data on adaptive functioning, emotional and social problems and self-concept in a specialized foster care service in Sweden. The focus of the study was on the development of the children and young people in placement. The Adaptive Behaviour Assessment System (ABAS-II) was used to measure adaptive functioning, and the Beck Youth Inventories of Emotional and Social Impairment (BYI) was used to measure self-rated emotional and social problems and self-concept. Self-ratings showed significant improvements in disruptive behaviour, anger, anxiety and depression. Adaptive functioning as rated by foster parents improved but not enough to catch up with the non-clinical norm group. The average adaptive functioning among the participants at baseline was considerably below the Swedish norm group. Similar to the results of a previous study of the same treatment model, children and young people rated improvement while their foster parents did not do so to the same extent. Possible explanations for this are discussed in the paper. The study is limited by the lack of a control group and by data attrition.     

Die Bildungsexpansion in der Schweiz und ihre Folgen

In this contribution the correlation of educational expansion and social inequality of educational opportunities (IEO) for social classes and gender has been investigated for Switzerland in the twentieth century. The empirical analysis is focused on the thesis of persistent inequalities claimed by Shavit and Blossfeld. For testing this thesis, data of the Swiss census in 1970, 1980, 1990, and 2000 has been utilized. First of all, it is found for Switzerland that the moderate educational expansion has been carried out by the succession of birth cohorts. Secondly, this process has led to decreasing IEO. However, after 1990, for the individuals younger than 22 years we have witnessed an increase of social inequalities in becoming eligible for university training. Overall, in favour of disadvantaged social classes, there is a decrease in IEO since the start of educational expansion in the 1950s. Therefore, the thesis of persistent inequalities has been not confirmed for Switzerland.     

DEA,directional distance functions and positive,affine data transformation

In this paper we take up the problem of positive, affine data translation within a Data Envelopment Analysis (DEA) framework.