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.     

The net asset value and stock prices of European real estate companies

The frequently large divergences between share price and net asset value (NAV) of listed real estate companies have been a key topic in real estate research for many years. However, previous research has mainly focused on the U.S. market, concentrating on companies’ performance ratios related to information from balance sheet statements and/or income statements as well as information from the stock market, and its results are not satisfying. This study, on the other hand, focuses on the European real estate market and presents a semi-rational model for explaining NAV spreads, taking into account performance ratios and market sentiment simultaneously. It appears that market sentiment in particular substantially improves the model, which explains more than 76% of the NAV spread. Thus, the developed model constitutes a significant improvement over previous studies on the explanation of NAV spreads.     

Practices of Dual Earner Couples Successfully Balancing Work and Family

Researchers have long explored conflict and strain in dual-career couples. Recently, the focus has begun to shift toward documenting the adaptive strategies of dual-earner couples in balancing family and work. The current study investigates workplace practices perceived as supportive in balancing work and family. Respondents were middle-class, dual-earner couples (N=47) who described themselves as successful in balancing family and work. These supportive practices include: flexible work scheduling, non-traditional work hours, professional/job autonomy, working from home, supportive supervisors, supportive colleagues and supervisees, and the ability to set firm boundaries around work. Additionally, many participants describe their efforts to actively secure employment at workplaces that offered family–friendly alternatives, and describe the tradeoffs they are willing to make.     

Bandwidth selection for kernel density estimation: a review of fully automatic selectors

On the one hand, kernel density estimation has become a common tool for empirical studies in any research area. This goes hand in hand with the fact that this kind of estimator is now provided by many software packages. On the other hand, since about three decades the discussion on bandwidth selection has been going on. Although a good part of the discussion is about nonparametric regression, this parameter choice is by no means less problematic for density estimation. This becomes obvious when reading empirical studies in which practitioners have made use of kernel densities. New contributions typically provide simulations only to show that the own selector outperforms some of the existing methods. We review existing methods and compare them on a set of designs that exhibit few bumps and exponentially falling tails. We concentrate on small and moderate sample sizes because for large ones the differences between consistent methods are often negligible, at least for practitioners. As a byproduct we find that a mixture of simple plug-in and cross-validation methods produces bandwidths with a quite stable performance.     

Visuelle Kommunikation und die Ethnomethoden der Ethnographie

Sociology mostly treats visuality either as a research object or as a method. Instead, I suggest that both can be drawn together and discussed symmetrically as instances of visual communication. This enables us to observe different layers of social practices not only in a verbal but also in a visual dimension. How do members of a situation communicate visually using artifacts, apparel, gestures, pointing or displaying? Furthermore, questions of methodology can be raised on an empirical base: ethnography itself can be described as a social practice that??using specific ethno-methods??systematically links situations and communications in order to reconstruct other social practices for sociological reasons. It uses, intensifies and produces traces of the observed practice and transfers them into sociological communication that can draw on visual communication, too.     

Primäre und sekundäre Effekte der sozialen Herkunft beim Übergang in die Hochschulbildung

Following Boudon social disparities at educational transitions can be linked to primary and secondary effects of social origin. Whereas primary effects describe social differentials in scholastic performance, secondary effects represent social differences in educational choices that are independent of performance. We use four panel surveys of graduate cohorts that have obtained eligibility for higher education between 1983 and 1999, provided by the German Higher Education Information System (HIS). By applying counterfactual decomposition methods we estimate the relative importance of primary and secondary effects at the transition to tertiary education. Our results indicate that secondary effects are the main driving force in the creation of social disparities at the transition to tertiary education, accounting for more than 80% of the differential between service class and working class offspring. Particularly financial aspects connected to the choice of post-secondary alternatives, interest in academic work and the type of Abitur degree can explain these effects. Furthermore, even though we observe a small increase in social selectivities at the transition to higher education, the relative importance of primary and secondary effects does not change within our observation period.     

ARE GOALS AND TOPICS INFLUENCED BY GENDER AND MODALITY IN THE INITIAL MARRIAGE AND FAMILY THERAPY SESSION?

Establishment of a goal is crucial to therapy, but identification of therapeutic goals may be difficult in conjoint therapy because each participant may identify a different problem. We examined the influence of gender on ability to successfully introduce therapeutic topics in marital and family therapy by conducting two studies. The first study evaluates the ability of therapists to identify therapeutic goals that matched goals prioritized by both women and men clients on pretherapy questionnaires. The second study examines the process of initial therapy sessions to see whether gender influences a client's ability to introduce a therapeutic topic. Results suggest that therapeutic topic is influenced by the interaction of gender and treatment modality. Specifically, therapists were better able to match women's pretherapy stated goals in marital therapy than family therapy, men were more successful at introducing topics in family therapy, and women were more successful at introducing topics in marital therapy.