Fractal basins of escape and the formation of spiral arms in a galactic potential with a bar

We investigate the dynamics in the close vicinity of and within the critical area in a 2D effective galactic potential with a bar of Zotos. We have calculated Poincar\'e surfaces of section and the basins of escape. In both the Poincar\'e surfaces of section and the basins of escape we find numerical evidence for the existence of a separatrix which hinders orbits from escaping out of the bar region. We present numerical evidence for the similarity between spiral arms of barred spiral galaxies and tidal tails of star clusters.Comment: 12 pages, 10 figures, accepted by MNRA

AliEn Resource Brokers

AliEn (ALICE Environment) is a lightweight GRID framework developed by the Alice Collaboration. When the experiment starts running, it will collect data at a rate of approximately 2 PB per year, producing O(109) files per year. All these files, including all simulated events generated during the preparation phase of the experiment, must be accounted and reliably tracked in the GRID environment. The backbone of AliEn is a distributed file catalogue, which associates universal logical file name to physical file names for each dataset and provides transparent access to datasets independently of physical location. The file replication and transport is carried out under the control of the File Transport Broker. In addition, the file catalogue maintains information about every job running in the system. The jobs are distributed by the Job Resource Broker that is implemented using a simplified pull (as opposed to traditional push) architecture. This paper describes the Job and File Transport Resource Brokers and shows that a similar architecture can be applied to solve both problems.Comment: 5 pages, 8 figures, CHEP 03 conferenc

AliEnFS - a Linux File System for the AliEn Grid Services

Among the services offered by the AliEn (ALICE Environment http://alien.cern.ch) Grid framework there is a virtual file catalogue to allow transparent access to distributed data-sets using various file transfer protocols. $alienfs$ (AliEn File System) integrates the AliEn file catalogue as a new file system type into the Linux kernel using LUFS, a hybrid user space file system framework (Open Source http://lufs.sourceforge.net). LUFS uses a special kernel interface level called VFS (Virtual File System Switch) to communicate via a generalised file system interface to the AliEn file system daemon. The AliEn framework is used for authentication, catalogue browsing, file registration and read/write transfer operations. A C++ API implements the generic file system operations. The goal of AliEnFS is to allow users easy interactive access to a worldwide distributed virtual file system using familiar shell commands (f.e. cp,ls,rm ...) The paper discusses general aspects of Grid File Systems, the AliEn implementation and present and future developments for the AliEn Grid File System.Comment: 9 pages, 12 figure

Ideological diversity, hostility, and discrimination in philosophy

Members of the field of philosophy have, just as other people, political convictions or, as psychologists call them, ideologies. How are different ideologies distributed and perceived in the field? Using the familiar distinction between the political left and right, we surveyed an international sample of 794 subjects in philosophy. We found that survey participants clearly leaned left (75%), while right-leaning individuals (14%) and moderates (11%) were underrepresented. Moreover, and strikingly, across the political spectrum, from very left-leaning individuals and moderates to very right-leaning individuals, participants reported experiencing ideological hostility in the field, occasionally even from those from their own side of the political spectrum. Finally, while about half of the subjects believed that discrimination against left- or right-leaning individuals in the field is not justified, a significant minority displayed an explicit willingness to discriminate against colleagues with the opposite ideology. Our findings are both surprising and important, because a commitment to tolerance and equality is widespread in philosophy, and there is reason to think that ideological similarity, hostility, and discrimination undermine reliable belief formation in many areas of the discipline

Linking stage-resolved population models with field observations: an integrated approach on population dynamics of Pseudocalanus elongatus in the German Bight.

The population dynamics of Pseudocalanus elongatus have been investigated within the framework of the GLOBEC-Germany project to gain a better understanding of its life cycle and population dynamics and to estimate secondary production in the North Sea. During an intensive field study in the German Bight between February and October 2004, experiments on reproduction were performed and data on length of copepodids and abundance were collected to characterize the population in the southern North Sea. This data set was used to update the literature- based parameterization of a population model for P. elongatus to investigate the population dynamics, life history and production in the German Bight. The ability of data to improve population models is also discussed. Pseudocalanus elongatus was found to be a major contributor to carbon uptake contributing about onethird of copepod production. Though the spatial variability in field observations was not reflected by the model, the simulation matched data within one order of magnitude at most stations. The high-resolution field observations and experiments mainly improved the parameterization of the reproductive parameters. Mortality is found to be a critical parameter due to its influence on population size. Using constant rates, though based on observation-derived estimates, seems not to capture realistic variability. Our study confirms the need for experimental and field data to build a robust parameterization for concentration-based population models

Tuning the critical magnetic field of the triplon Bose-Einstein condensation in Ba3−x_{3-x}Srx_xCr2_2O8_8

The structure and magnetic interactions of the triplon Bose-Einstein condensation candidates Ba$_3$Cr$_2$O$_8$ and Sr$_3$Cr$_2$O$_8$ have been studied thoroughly in the literature, but little is known about a possible triplon condensation in the corresponding solid solution Ba$_{3-x}$Sr$_x$Cr$_2$O$_8$. We have prepared various members of this solid solution and systematically examined their magnetic properties in high magnetic fields up to 60 T and at low temperatures down to 340 mK, by means of pulsed field and cantilever magnetometry. From these experiments for $x\in\{3,2.9,2.8,2.7,2.6,2.5\}$, we find that the critical fields of Ba$_{3-x}$Sr$_x$Cr$_2$O$_8$ decrease monotonically as a function of the Sr content $x$. This change is in good agreement with the earlier reported variation of the magnetic interactions in these compounds

Segmented Europeanization: the transnationalization of public spheres in Europe ; trends and patterns / Michael Brüggemann; Stefanie Sifft; Katharina Kleinen

The existence of a European public sphere, a public network of exchange of opinions and ideas on political issues, has come to be seen as a prerequisite for the democratic legitimacy of the European Union. The paper conceptualizes the Europeanization of the national public spheres as a gradual process that may occur on four different dimensions: 1. monitoring governance, 2. mutual observation, 3. discursive exchange, and 4. collective identification with Europe. It then presents the results of our empirical research on the transnationalization of public spheres in Europe: What is the prevailing pattern of Europeanization that can be observed in different countries of the EU? We have conducted a quantitative content analysis of the political discourses in quality newspapers of five EU member states (Austria, Denmark, France, Germany, Great Britain) over a period of twenty years. According to our analysis of more than 3,000 articles the main pattern of transnationalization to be found in all countries is segmented Europeanization: Within each public sphere we find more and more talk about European institutions and policies but there is no indication of an increase in the debate in between the national public spheres. In addition, we find weak indications of a gradually developing European we-perspective. --

Do mountain tourists demand ecotourism? Examining moderating influences in an Alpine tourism context

Ecotourists appreciate nature and are willing to learn about nature and ecology. Therefore ecotourism is often seen as a product package that supports sustainable tourism development. This study contributes to existing research in the field of ecotourism as it investigates how travel motives and environmental concern of mountain tourists influences their actual demand for ecotourism. A survey of mountain tourists in the Austrian Alps was conducted and reveals a positive relationship between environmental concern and ecotourism demand. The study measured travel motives, which are compatible and incompatible with ecotourism and showed how these motives influence actual demand of ecotourism. Furthermore it is postulated that education, income and the intention to revisit the destination moderate the relationship between environmental concern, mountain tourists’ motives and the tourists’ demand for ecotourism. For destination marketing it can be stated that higher educated mountain tourists with a high disposable income are a vital market segment, which should be targeted for ecotourism in the mountains. Research recommendations are highlighted and focus on loyal visitors, as it remains unclear whether loyalty with an ecotourism destination strengthens the demand for ecotourism