Analysis of breeding bird communities along an urban-rural gradient in Berlin,Germany, by Hasse Diagram Technique

Breeding bird communities in Berlin were investigated at five study sites, which represent an structural urban-rural gradient, from densely built-up areas with sealed ground to green areas such as large parks. In this paper, we tested the Hasse Diagram Technique (HDT), an approach belonging to partial order theory, for its appropriateness to extract information about changes in species composition from our data set. As expected, the overall number of bird species was positively correlated with the urban-rural gradient, increasing from 12 found in the city center to 28 in an urban park. By HDT analysis, four different sub-groups of birds could be identified, contributing differentially to the increase in species number: (1) ubiquists, i.e., species found at each study site, (2) a sub-group, the species’ number of which was positively correlated with the urban-rural gradient, increasing with increasingly green areas, (3) a sub-group, the species’ number of which was negatively correlated with the urban-rural gradient, decreasing with a declining density of buildings, and (4) species, the distribution of which did not show any correlation with the urban-rural gradient. The results show that HDT is a suitable tool for formalized analysis of the pattern of species’ communities along an environmental gradient.     

Wodurch kann die soziale Ungleichheit des Schulerfolgs am stärksten verringert werden?

Social inequality of student achievement in school has a variety of causes, all of them are well investigated scientifically. But, if a particular cause could be neutralized, which of these causes would have the strongest effect of reducing social inequality? Based on data of the PISA 2000 study, the contribution argues that the secondary social effect, which mainly represents the parental decisions for transitions to different branches of the higher educational system, has at least the same quantity as the primary social effect, which consists in all family background conditions of a student. Simple simulations show how the social inequality will change, if either the primary or the secondary social effect are neutralized. These changes cannot be forecasted in an easy or linear way under different conditions.     

Xinjiang’s geographies in motion

Starting from the idea that places are socially constructed, this essay explores how a place is established and lived in Xinjiang by the members of the area’s two largest ethnicities, the Uyghur and the Han. This article demonstrates that there are differences in the ways Han and Uyghur imagine and ‘live’ Xinjiang.¹1. Xinjiang is not a very fortunate toponym to use here because it is a Han-language term (meaning ‘New Frontier’) that was imposed during the colonization of the region by the Qing Dynasty (1644–1911). However, since there is no other term that comprises both regions of Tarim Basin and Dzungaria and also eastern Xinjiang, I am compelled to use it. For a discussion of the complex question of toponym-usage in this region see Millward, Eurasian Crossroads.View all notes At the same time it asserts that Uyghur and Han do not establish distinct spatial relationships just because of their ethnicity, but also to enhance ethnic solidarity and boundaries vis-à-vis the other. This essay also demonstrates that places are historically contingent, and discusses the ways in which the influx of temporary Han migrants and settlers – and Han capital – has generated new layers of spatial meaning and new power differentials.     

La qualité de l'emploi en Amérique latine: théorie et faits

Traditionnellement, la littérature sur le développement consacrée aux marchés du travail d'Amérique latine s'est concentrée sur le nombre d'emplois et la productivité. Mais, étant donné la persistance d'une forte proportion d'emplois informels ou précaires, pour que l'analyse ait du sens, il faut aussi considérer des implications du statut professionnel sur la qualité de l'emploi. Partant d'observations faites ces dernières décennies, les auteurs concluent que la plupart des aspects de cette qualité – protection sociale comprise – dépendent de la signature d'un contrat écrit. Ce constat les conduit à formuler quelques suggestions pour stabiliser l'emploi formel et assurer un financement suffisant de la protection sociale.     

Computation of Sharp Bounds on the Expected Value of a Supermodular Function of Risks with Given Marginals

We show that the rearrangement algorithm (RA) introduced in Puccetti and Rüschendorf (2012 Puccetti, G., Rüschendorf, L. (2012). Computation of sharp bounds on the distribution of a function of dependent risks. Journal of Computational and Applied Mathematics 236(7):1833–1840.[Crossref], [Web of Science ®] , [Google Scholar]) to compute distributional bounds can be used also to compute sharp lower and upper bounds on the expected value of a supermodular function of d random variables having fixed marginal distributions. Compared to the analytical methods existing in the literature the algorithm is widely applicable, more easily obtained and gives insight into the dependence structures attaining the bounds.     

Correction of 'On the Inconsistency of Equilibrium Refinement'

Theory and Decision -     

E-Capacities and the Ellsberg Paradox

Ellsberg's (1961) famous paradox shows that decision-makers give events with known probabilities a higher weight in their outcome evaluation. In the same article, Ellsberg suggests a preference representation which has intuitive appeal but lacks an axiomatic foundation. Schmeidler (1989) and Gilboa (1987) provide an axiomatisation for expected utility with non-additive probabilities. This paper introduces E-capacities as a representation of beliefs which incorporates objective information about the probability of events. It can be shown that the Choquet integral of an E-capacity is the Ellsberg representation. The paper further explores properties of this representation of beliefs and provides an axiomatisation for them.     

A macroeconomic potential describing structural change of the economy

For the purpose of describing change in an economy's structure, and addressing issues of transformation, the notion of a time-dependent macroeconomic potential function is introduced. It penalizes deviations from equilibrium (entrepreneurial error) and induces moves toward equilibrium. Thus, from the concept of a potential function is derived the concept of short-term and long-term change forces. We focus here on the long-term structural changes of an economy as distinct from short-term cyclical variations, and we represent economic transformations as phase-transitions between monostable and ambiguous bistable states of the economy. One important feature of the potential function approach is that the parameter of the potential can be determined from empirical data. In particular, the parameters can be regressed for input variables. Hence, a relationship has been established between the structural change force and a set of input variables, some of which are controlled in part by either public or private sector agents. The method has been applied to West German and United States industry data for 1950–1980.