A Distribution Law for CCS and a New Congruence Result for the pi-calculus

We give an axiomatisation of strong bisimilarity on a small fragment of CCS that does not feature the sum operator. This axiomatisation is then used to derive congruence of strong bisimilarity in the finite pi-calculus in absence of sum. To our knowledge, this is the only nontrivial subcalculus of the pi-calculus that includes the full output prefix and for which strong bisimilarity is a congruence.Comment: 20 page

Supporting Data mining of large databases by visual feedback queries

In this paper, we describe a query system that provides visual relevance feedback in querying large databases. Our goal is to support the process of data mining by representing as many data items as possible on the display. By arranging and coloring the data items as pixels according to their relevance for the query, the user gets a visual impression of the resulting data set. Using an interactive query interface, the user may change the query dynamically and receives immediate feedback by the visual representation of the resulting data set. Furthermore, by using multiple windows for different parts of a complex query, the user gets visual feedback for each part of the query and, therefore, may easier understand the overall result. Our system allows to represent the largest amount of data that can be visualized on current display technology, provides valuable feedback in querying the database, and allows the user to find results which, otherwise, would remain hidden in the database

Additional experimental evidence for a solar influence on nuclear decay rates

Additional experimental evidence is presented in support of the recent hypothesis that a possible solar influence could explain fluctuations observed in the measured decay rates of some isotopes. These data were obtained during routine weekly calibrations of an instrument used for radiological safety at The Ohio State University Research Reactor using Cl-36. The detector system used was based on a Geiger-Mueller gas detector, which is a robust detector system with very low susceptibility to environmental changes. A clear annual variation is evident in the data, with a maximum relative count rate observed in January/February, and a minimum relative count rate observed in July/August, for seven successive years from July 2005 to June 2011. This annual variation is not likely to have arisen from changes in the detector surroundings, as we show here.Comment: 8 pages, 6 figure

A computational framework for elliptic inverse problems with uncertain boundary conditions

This project concerns the computational solution of inverse problems formulated as partial differential equation (PDE)-constrained optimization problems with interior data. The areas addressed are twofold. First, we present a novel software architecture designed to solve inverse problems constrained by an elliptic system of PDEs. These generally require the solution of forward and adjoint problems, evaluation of the objective function, and computation of its gradient, all of which are approximated numerically using finite elements. The creation of specialized "layered"' elements to perform these tasks leads to a modular software structure that improves code maintainability and promotes functional interoperability between different software components. Second, we address issues related to forward model definition in the presence of boundary condition (BC) uncertainty. We propose two variational formulations to accommodate that uncertainty: (a) a Bayesian formulation that assumes Gaussian measurement noise and a minimum strain energy prior, and (b) a Lagrangian formulation that is completely free of displacement and traction BCs. This work is motivated by applications in the field of biomechanical imaging, where the mechanical properties within soft tissues are inferred from observations of tissue motion. In this context, the constraint PDE is well accepted, but considerable uncertainty exists in the BCs. The approaches developed here are demonstrated on a variety of applications, including simulated and experimental data. We present modulus reconstructions of individual cells, tissue-mimicking phantoms, and breast tumors

From coordinating in space to coordinating through space: A spatial perspective on coordinating

The spatial turn in organization studies has redefined our understanding of physical space, portraying it no longer as a passive backdrop for organizational actions but as actively produced through organizational actions and as shaping organizational actions in turn. In contrast to other areas of organization studies, research on coordination has not yet harvested the potential of this spatial turn for its theorizing, still treating physical space predominantly as context. In this article we develop a spatial perspective on coordination that acknowledges how coordination practices (re)produce physical space, indirectly affecting coordination outcomes; and how spatial production might even be purposefully employed for coordinating. Building on Lefebvre’s theory of spatial production, we theorize how actors might purposefully coordinate through configurational processes of designing, enacting and shaping their collective experience of physical space. This conceptual shift from coordinating in space to coordinating through space has important implications for coordination research and practice

Trait-based approaches to analyze links between the drivers of change and ecosystem services: Synthesizing existing evidence and future challenges

Understanding the responses of biodiversity to drivers of change and the effects of biodiversity on ecosystem properties and ecosystem services is a key challenge in the context of global environmental change. We performed a systematic review and meta-analysis of the scientific literature linking direct drivers of change and ecosystem services via functional traits of three taxonomic groups (vegetation, invertebrates, and vertebrates) to: (1) uncover trends and research biases in this field; and (2) synthesize existing empirical evidence. Our results show the existence of important biases in published studies related to ecosystem types, taxonomic groups, direct drivers of change, ecosystem services, geographical range, and the spatial scale of analysis. We found multiple evidence of links between drivers and services mediated by functional traits, particularly between land-use changes and regulating services in vegetation and invertebrates. Seventy-five functional traits were recorded in our sample. However, few of these functional traits were repeatedly found to be associated with both the species responses to direct drivers of change (response traits) and the species effects on the provision of ecosystem services (effect traits). Our results highlight the existence of potential “key functional traits,” understood as those that have the capacity to influence the provision of multiple ecosystem services, while responding to specific drivers of change, across a variety of systems and organisms. Identifying “key functional traits” would help to develop robust indicator systems to monitor changes in biodiversity and their effects on ecosystem functioning and ecosystem services supplyFinancial support was received from the Spanish Ministry of Economy and Competitiveness (Project CGL2014-53782-P). MGL was funded by a postdoctoral grant from the Spanish National Institute for Agriculture and Food Research and Technology (INIA), which is cofounded by the European Social Fun

Electron-Ion Collider impact study on the tensor charge of the nucleon

In this letter we study the impact of the Electron-Ion Collider (EIC) on the phenomenological extraction of the tensor charge from a QCD global analysis of single transverse-spin asymmetries (SSAs). We generate EIC pseudo-data for the Collins effect in semi-inclusive deep-inelastic scattering for proton and $^{3\!}He$ beams across multiple center-of-mass energies. We find a significant reduction in the uncertainties for the up, down, and isovector tensor charges that will make their extraction from EIC data on SSAs as precise as current lattice QCD calculations. We also analyze the constraints placed by future data from the proposed SoLID experiment at Jefferson Lab, discuss its important complementary role to the EIC, and present the combined impact from both facilities.Comment: 12 pages, 6 figures, 1 table; minor changes; version to be published in PL

Zentrale Befunde zu aktuellen Arbeitsmarktthemen

Die Zahlen zur Beschäftigung und zum Leistungsbezug rechtfertigen es gegenwärtig nicht, die Zuwanderung aus Bulgarien und Rumänien pauschal als 'Armutszuwanderung' zu qualifizieren. Zur Jahresmitte 2013 waren rund 60 Prozent der Bulgaren und Rumänen im erwerbsfähigen Alter in Deutschland erwerbstätig. Die Arbeitslosenquote lag bei 7,4 Prozent und der Anteil der SGB-II-Leistungsempfänger an der bulgarischen und rumänischen Bevölkerung bei 10 Prozent. Allerdings haben 46 Prozent der Bulgaren und Rumänen, die nach 2007 zugewandert sind, keine abgeschlossene Berufsausbildung. In einigen strukturschwachen Kommunen wie Duisburg, Dortmund und Berlin konzentrieren sich die sozialen und ökonomischen Probleme der Bulgaren und Rumänen. Hier sind nicht nur die Arbeitslosen- und Leistungsempfängerquoten zum Teil sehr hoch. Vor allem sind hier 60 bis 75 Prozent der Bulgaren und Rumänen weder erwerbstätig noch im Leistungsbezug. Durch Einführung der vollständigen Arbeitnehmerfreizügigkeit steigen einerseits die Beschäftigungsmöglichkeiten im ersten Arbeitsmarkt, andererseits erweitert sich der Kreis der potenziellen Leistungsbezieher. Unter optimistischen Annahmen wird die Zahl der SGB-II-Leistungsempfänger zum Jahresende 2014 auf 50.000 bis 58.000, unter extrem pessimistischen Annahmen auf 80.000 bis 93.000 Personen steigen. Die Arbeitsmarktpolitik sollte sich vor allem auf die Vermittlung von geringer Qualifizierten fokussieren. Strukturschwache Kommunen, in denen sich die Probleme konzentrieren, könnten mit Mitteln aus dem Bundeshaushalt kompensiert werden. Der Leistungsausschluss von EU-Bürgern, die sich zum Zweck der Arbeitssuche in Deutschland aufhalten, ist ökonomisch sinnvoll und sollte beibehalten werden