Onset of cavitation in the quark-gluon plasma

We study the onset of bubble formation (cavitation) in the quark-gluon plasma as a result of the reduction of the effective pressure from bulk-viscous corrections. By calculating velocity gradients in typical models for quark-gluon plasma evolution in heavy-ion collisions, we obtain results for the critical bulk viscosity above which cavitation occurs. Since present experimental data for heavy-ion collisions seems inconsistent with the presence of bubbles above the phase transition temperature of QCD, our results may be interpreted as an upper limit of the bulk viscosity in nature. Our results indicate that bubble formation is consistent with the expectation of hadronisation in low-temperature QCD.Comment: 12 pages, 2 figure

Income dynamics in three societies: an investigation of social dynamics using old and new types of social indicators

This paper* sets out to offer new insight into social change, especially social transformation. The authors have drawn up new types of social indicators to encapsulate the nature of social change, with the intention of widening its meaning. The investigation draws on longitudinal panel studies: the German Socio-Economic Panel Study 1990–96 (GSOEP) and the Hungarian Household Panel 1992–96 (HHP). The single, albeit crucial social dimension examined is the income position of families, including the mobility of families within the income structure. The analysis takes a comparative and a longitudinal approach. Hungary and East Germany, as societies in transition, are compared with West Germany, as a case of ‘usual’ social change, while the income mobility of individuals is traced over time. Both these aspects are examined in relation to modernization theories. While classical measures such as the Gini Coefficient show a remarkable stability of income inequality, the indicators elaborated here reveal a high degree of individual movement behind the macro stability. --

Particle spectra and HBT radii for simulated central nuclear collisions of C+C, Al+Al, Cu+Cu, Au+Au, and Pb+Pb from Sqrt(s)=62.4-2760 GeV

We study the temperature profile, pion spectra and HBT radii in central symmetric and boost-invariant nuclear collisions using a super hybrid model for heavy-ion collisions (SONIC) combining pre-equilibrium flow with viscous hydrodynamics and late-stage hadronic rescatterings. In particular, we simulate Pb+Pb collisions at Sqrt(s)=2.76 TeV, Au+Au, Cu+Cu, Al+Al, and C+C collisions at Sqrt(s)=200 GeV and Au+Au, Cu+Cu collisions at Sqrt(s)=62.4 GeV. We find that SONIC provides a good match to the pion spectra and HBT radii for all collision systems and energies, confirming earlier work that a combination of pre-equilibrium flow, viscosity and QCD equation of state can resolve the so-called HBT puzzle. For reference, we also show p+p collisions at Sqrt(s)=7 TeV. We make tabulated data for the 2+1 dimensional temperature evolution of all systems publicly available for the use in future jet energy loss or similar studies.Comment: 9 pages, 5 figures, 2 tables; v2: fixed typos, updated figures; v3: minor changes, matches published versio

Is the Regional Perspective Useful?: Rural and Urban Quality of Life ; an Assessment

In Germany, processes can be observed that have long been out of keeping with the principle of equality of opportunity. Unemployment is concentrated in the structurally weak peripheral areas, in Eastern Germany in particular; emigration of young and better-educated people to the West is not diminishing, but contrary to expectation is again on the increase; aging pro-cesses have set in already, and when it comes to the provision of infrastructure, e.g. in the field of professional training, some regions are already suffering from considerable problems. These difficulties are frequently interpreted as differences between East and West and are explained away as problems resulting from reunification, such as the deindustrialization and restructuring of the economy and the enormous decline in the birth rate in Eastern Germany. Although these problems cannot just be attributed to social transformation and the birth rate crisis alone, being subject to more general processes of intensified globalization and the aging of society, the increasing regional disparities are rarely considered in the overall context of regional development patterns throughout Germany. Moreover, the difficulty of even obtaining data for purposes of comparison generally means that an international yardstick is lacking when regional developments are analyzed. The present study investigates regional disparities over a period of time in the light of subjective and objective indicators of the quality of life for individuals. To this end, we make use of data from the Wohlfahrtssurvey [Welfare Survey] from 1978 to 2001, among other sources. On the basis of the Euromodule that has been established at the WZB, we compare current regional patterns in Germany with those in other European countries. This approach makes it possible to provide information on the scale of regional disparities in various different countries, and to identify privileged and handicapped regions with reference to standards of living and the sense of wellbeing. The study's findings show that, in the past twenty-five years, welfare in Western Germany has evened out at a higher level, but currently a trend towards increasing economic disparity is discernible. In comparison with other European countries, on the other hand, the differences (regional differences) within Germany are comparatively slight.

Q2S Enhanced Pedagogy: Developing Critical Listening Skills in Business School Students to Enhance On-The-Job Performance

A common complaint heard from many business managers and executives is that while recent business school graduates are relatively well-equipped for the technical aspects of their jobs, they often lack critical communication-related skills, thus limiting their organizational effectiveness. This article describes feedback received from a group of Southern California business executives indicating that active listening is one of the most important of these communication skills - and one often lacking in recent business school graduates - and offers one classroom exercise that can be used to help students practice this critical communication skill

FRAND Access to Data: Perspectives from the FRAND Licensing of Standard-Essential Patents for the Data Act Proposal and the Digital Markets Act

This article evaluates how the principles developed for the fair, reasonable and non-discriminatory (FRAND) licensing of standard-essential patents could be applied to FRAND data access as envisaged under the Digital Markets Act and the Data Act and proposes a negotiation scheme to specify the FRAND obligations. Firstly, this article describes the access rights under the Data Act and identifies its four layers to accelerate data sharing (Section 2). Secondly, the role of FRAND data sharing in the EU Data Package is described, and the specifics of FRAND in the context of the Data Act and the Digital Markets Act are developed (Section 3). Based thereon, the differences and commonalities of data sharing as envisaged in the Acts with respect to the FRAND licensing of standard-essential patents are described, and a negotiation scheme for FRAND terms under the current Data Act Proposal is developed under adaptation of the principles from Huawei/ZTE (Section 4)

Income dynamics in three societies: an investigation of social dynamics using "old" and "new" types of social indicators

"This paper sets out to offer new insight into social change, especially social transformation. The authors have drawn up new types of social indicators to encapsulate the nature of social change, with the Intention of widening its meaning. The investigation draws an longitudinal panel studies: the German Socio-Economic Panel Study 1990-96 (GSOEP) and the Hungarian Household Panel 1992-96 (HHP). The single, albeit crucial social dimension examined is the income position of families, including the mobility of families within the income structure. The analysis takes a comparative and a longitudinal approach. Hungary and East Germany, as societies in transition, are compared with West Germany, as a case of 'usual' social change, while the income mobility of individuals is traced over time. Both these aspects are examined in relation to modernization theories. White classical measures such as the Gini Coefficient show a remarkable stability of income inequality, the indicators elaborated here reveal a high degree of individual movement behind the macro stability." (author's abstract)Dieser Beitrag bietet neue Einsichten über Prozesse des sozialen Wandels, insbesondere in Transformationsgesellschaften. Die Autoren benutzen dazu "neue" Sozialindikatoren, mit denen Prozesse des sozialen Wandels besser als bisher abgebildet werden können. Die empirische Untersuchung basiert dabei auf vergleichenden Längsschnitt-Panel-Studien: dem deutschen sozio-oekonomischen Panel 1990-96 (SOEP) und dem ungarischen Haushalts-Panel 1992-96 (HHP). Die Einkommenspositionen von Familien unter Berücksichtigung ihrer Mobilität innerhalb der sich verändernden Einkommensstruktur stehen als entscheidende, soziale Dimension im Mittelpunkt. Die Analysen der Einkommensmobilität erfolgen vergleichend und im Längsschnitt. Ungarn und Ostdeutschland, als Transformationsgesellschaften, werden mit Westdeutschland verglichen, wobei Westdeutschland als Beispiel für "normalen" sozialen Wandel steht. Beobachtbare individuelle und strukturelle Mobilitätsprozesse werden in Beziehung zu Modernisierungstheorien untersucht. Im Gegensatz zur Untersuchung anhand klassischer Meßinstrumente wie dem Gini-Koeffizienten, die eine hohe Stabilität der Einkommensgleichheit dokumentieren, zeigen die hier verwendeten Indikatoren ein hohes Maß an individueller Bewegung hinter der Makro-Stabilität auf. (HH

Adaptive work placement for query processing on heterogeneous computing resources

The hardware landscape is currently changing from homogeneous multi-core systems towards heterogeneous systems with many di↵erent computing units, each with their own characteristics. This trend is a great opportunity for database systems to increase the overall performance if the heterogeneous resources can be utilized eciently. To achieve this, the main challenge is to place the right work on the right computing unit. Current approaches tackling this placement for query processing assume that data cardinalities of intermediate results can be correctly estimated. However, this assumption does not hold for complex queries. To overcome this problem, we propose an adaptive placement approach being independent of cardinality estimation of intermediate results. Our approach is incorporated in a novel adaptive placement sequence. Additionally, we implement our approach as an extensible virtualization layer, to demonstrate the broad applicability with multiple database systems. In our evaluation, we clearly show that our approach significantly improves OLAP query processing on heterogeneous hardware, while being adaptive enough to react to changing cardinalities of intermediate query results