In search of charismatic leaders or: You get what you ask for

The Global Leadership and Organizational Behavior Effectiveness (GLOBE) study is currently the most comprehensive research endeavor that set out to answer - amongst others - whether or not charismatic/value-based leadership is universally seen to contribute to effective leadership. The results have been appearing in various journals and books supporting this assumption and conveying the image that charismatic leaders are worldwide successful. Given the study's scope and exemplary status we suspect that the aforementioned result will receive the status of a 'given fact' if the study is not critically reviewed. The paper strives to fulfill this call by taking a 'closer look' at the conception of charisma in today's charismatic leadership theories as well as the GLOBE study, its results and interpretation. We argue that the items that are universally endorsed are not primarily pertaining to charisma but rather represent common, positive connoted leadership attributes. Moreover, the paper proposes an alternative to the research approach adopted by GLOBE, i.e. we present a qualitative leadership study and its result and will discuss whether or not charismatic leadership can be found in the German-speaking part of Switzerland. Our conclusion suggests that the answer to this question is dependent upon the adopted research approach. The paper closes by outlining implications and encouraging critical reviews of established research results

Quantum Entanglement and the Two-Photon Stokes Parameters

A formalism for two-photon Stokes parameters is introduced to describe the polarization entanglement of photon pairs. This leads to the definition of a degree of two-photon polarization, which describes the extent to which the two photons act as a pair and not as two independent photons. This pair-wise polarization is complementary to the degree of polarization of the individual photons. The approach provided here has a number of advantages over the density matrix formalism: it allows the one- and two-photon features of the state to be separated and offers a visualization of the mixedness of the state of polarization.Comment: 15 pages, 2 figures, accepted for publication in Opt. Com

Autonomie in IT-Systemen : Ein Konzeptionelles Modell

Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG geförderten) Allianz- bzw. Nationallizenz frei zugänglich.This publication is with permission of the rights owner freely accessible due to an Alliance licence and a national licence (funded by the DFG, German Research Foundation) respectively.Die Erforschung und Anwendung von autonomen Systemen ist momentan in der Informatik ein Themengebiet von wachsendem Interesse. Die Aussicht, mit autonomen Verfahren komplexe Systeme handhabbar zu machen und Kosteneinsparungen bei deren Betrieb zu erzielen, hat bereits die Softwareindustrie auf dieses Thema gelenkt und zu neuartigen Produkten geführt. Andererseits darf die Verlässlichkeit eines Systems nicht aufgrund eines autonomen Verfahrens herabgesetzt werden. Dieses Spannungsfeld ist ein Fokus verschiedener Forschungsbemühungen, um autonome Systeme alltagstauglich zu machen.Beim Gebiet der autonomen Systeme handelt es sich um ein junges Themengebiet, welches noch nicht durch allgemein akzeptierte Definitionen geprägt ist. Dadurch entsteht der Bedarf einer terminologischen Basis, die sich momentan in der Phase der Etablierung befindet. Diese Arbeit beteiligt sich an diesem Prozess und schlägt ein konzeptionelles Modell vor. Dieses Modell benennt die grundlegenden Termini und zeigt deren Zusammenhänge auf. Es beschreibt eine Interpretation der relevanten Begriffe und leitet daraus Relationen ab. Auf diese Weise fördert es das gemeinsame Verständnis und erleichtert die Kommunikation bezüglich spezifischer Fragestellungen innerhalb dieses Gebietes

Entanglement, Mixedness, and Spin-Flip Symmetry in Multiple-Qubit Systems

A relationship between a recently introduced multipartite entanglement measure, state mixedness, and spin-flip symmetry is established for any finite number of qubits. It is also shown that, within those classes of states invariant under the spin-flip transformation, there is a complementarity relation between multipartite entanglement and mixedness. A number of example classes of multiple-qubit systems are studied in light of this relationship.Comment: To appear in Physical Review A; submitted 14 May 200

Strangeness Enhancement Scenarios: Fireball or Independent Strings?

Due to the long-standing discrepancy between NA35 and NA36 data on $\Lambda$ production, two drastically different scenarios of strangeness enhancement are still possible. Independent string models, such as the dual parton model, lead to results close to the NA36 data. On the contrary, the NA35 results can only be described by introducing full final state rescattering of the produced particles. The corresponding predictions for central $Pb$-$Pb$ collisions at CERN energies differ by a factor 3 to 4. Preliminary data on the net proton ($p$-$\bar{p}$) rapidity distribution in $Pb$-$Pb$ collisions favor the independent string scenario.Comment: 12 pages, Plain Tex, no figure

Quantum Correlations in non-Markovian Environments

We have studied the analytical Markovian and non-Markovian dynamics of quantum correlations, such as entanglement, quantum discord and Bell nonlocalities for three noisy qubits. Quantum correlation as measured by quantum discord is found to be immune to death contrary to entanglement and Bell nonlocality for initial GHZ- or W-type mixed states

SPITZER survey of dust grain processing in stable discs around binary post-AGB stars

Aims: We investigate the mineralogy and dust processing in the circumbinary discs of binary post-AGB stars using high-resolution TIMMI2 and SPITZER infrared spectra. Methods: We perform a full spectral fitting to the infrared spectra using the most recent opacities of amorphous and crystalline dust species. This allows for the identification of the carriers of the different emission bands. Our fits also constrain the physical properties of different dust species and grain sizes responsible for the observed emission features. Results: In all stars the dust is oxygen-rich: amorphous and crystalline silicate dust species prevail and no features of a carbon-rich component can be found, the exception being EPLyr, where a mixed chemistry of both oxygen- and carbon-rich species is found. Our full spectral fitting indicates a high degree of dust grain processing. The mineralogy of our sample stars shows that the dust is constituted of irregularly shaped and relatively large grains, with typical grain sizes larger than 2 micron. The spectra of nearly all stars show a high degree of crystallinity, where magnesium-rich end members of olivine and pyroxene silicates dominate. Other dust features of e.g. silica or alumina are not present at detectable levels. Temperature estimates from our fitting routine show that a significant fraction of grains must be cool, significantly cooler than the glass temperature. This shows that radial mixing is very efficient is these discs and/or indicates different thermal conditions at grain formation. Our results show that strong grain processing is not limited to young stellar objects and that the physical processes occurring in the discs are very similar to those in protoplanetary discs.Comment: 22pages, 50 figures (in appendix), accepted for A&