Absenteeism and the risk of involuntary unemployment: A dynamic analysis

Absence from work is a risky activity for an employed worker, as it may lead to dismissal and involuntary unemployment. The cost of unemployment to a worker depends, however, on absence behavior had the worker remained employed. Hence, absence decisions over time are interrelated. This article examines the dynamic and some comparative static aspects of the absence decision under uncertainty: the nature of its variation over time, its response to variations in the unemployment rate, and its alleged subjection to a moral hazard effect in the presence of an unemployment insurance program.     

Social identity and violence among immigrant adolescents

Whereas traditional criminological theories treat juvenile delinquency largely as a reactive and expressive behavior that only seldom leads to specialized criminal offending or a criminal career, this article proposes an alternative classification of offenses that accounts for the difference between youthful reactive conduct and specialized criminality. It examines the effect of immigration on delinquency among juvenile Russians in Israel. In contrast to previous work that has examined the criminogenic effect of immigration without differentiating specific types of delinquency, this study investigates the immigration effect on eclectic as well as specialized delinquency. Based on survey data from face-to-face interviews with 910 immigrant youths from the former Soviet Union in Israel, the study finds important results regarding the integration of juvenile immigrants in modern societies. In contrast to the assumption that assimilation in multicultural societies represents a safe way for social adaptation and to prevent specific kinds of violent behavior, the authors find empirical support for a more sophisticated approach. Furthermore, the results underline the importance in differentiating between distinct forms of violence.     

Supplying lead firms,intangible assets and power in global value chains: Explaining governance in the fertilizer chain

Global suppliers of agricultural inputs such as seeds, fertilizers and agrochemicals exert increasing degrees of power in global value chains (GVCs). Although the GVC literature has explained how global buyers govern GVCs from the buying-end, the question of how global suppliers achieve governance from the supplying-end remains underexplored. We address this gap by combining a multidimensional typology of power with literature on intangible assets. We argue that intangible assets are crucial resources for global suppliers to morph otherwise ungovernable supply chains for undifferentiated input commodities into more sophisticated and governable GVCs. We illustrate our argument with the case of the global fertilizer supplier, YARA International. YARA's intangible asset investments were instrumental in governing the value chain integration of Tanzanian smallholder farmers. They allowed YARA to exert more than bargaining power (demonstrative, institutional and constitutive power) and to effectively position itself as supplying lead firm in Tanzania's agro-industrial GVC.     

Horizontal and vertical island biogeography of arthropods on green roofs: a review

From an ecological perspective, urban green roofs can be viewed as green islands embedded in an urban matrix. Island biogeography theory suggests that species richness on an island is the outcome of dynamic equilibrium between immigration and extinction. Immigration is affected by the size of an island and distance of an island from a colonizing source. In the context of green roofs, building height and horizontal distance from green areas can potentially be a limiting factor for many species. Here, we considered two distance components of green roofs - vertical (building height) and horizontal (distance of building from open green areas). Based on island biogeography theory, we would expect species richness or community similarity to be negatively related to horizontal or vertical distances from colonizing sources. The green roof literature addressing such questions is currently sparse. In our review comprised of 10 studies, we were unable to identify consistent statistically significant richness-distance or community similarity-distance (vertical or horizontal) relationships. The absence of statistically significant relationships could be due in large part to low statistical power as a consequence of both the paucity of roofs and limited range of vertical distances in many of the existing studies. In addition, these roofs differ in numerous aspects (e.g. roof size, age, substrate type, plant composition and building height). The low number of replicates, combined with the lack of homogeneity among replicates combines to reduce statistical power and our ability to detect differences.     

Commitment of Juveniles to Training Schools

The study analyzes commitment rates to training schools, average length of stay and the facility utilization in the various states over the period 1979–1990. Based on a regression analysis of the data, we found that only the bed ratio, which is the number of beds per 100,000 eligible population, and average length of stay in training schools are significant in explaining the changes of commitment rate over the years. The paper focuses on the meaning of the variation between states on the commitment rate, the average length of stay and facility utilization might have in terms of correctional policy. There is also a discussion of our findings that the only significant variables in explaining commitment rate change were institutional variables that influence correctional policy.     

Exploring sequences: a graphical tool based on multi-dimensional scaling

Summary.  Sequence analysis has become one of the most used and discussed tools to describe life course trajectories. We introduce a new tool for the graphical exploratory analysis of sequences. Our plots combine standard sequence plots with the results that are provided by multi-dimensional scaling. We apply our procedure to describe work and family careers of Israeli women by using data from the Israel Social Mobility Survey. We first focus on some preliminary choices relative to the definition of the sequences: the age span, the length of the sequences and the set of states registered in each time period. We then describe how our plots can be used to gain insights about the main features of sequences and about the relationships between sequences and external information.