Spacetime metric from linear electrodynamics

The Maxwell equations are formulated on an arbitrary (1+3)-dimensional manifold. Then, imposing a (constrained) linear constitutive relation between electromagnetic field $(E,B)$ and excitation $({\cal D},{\cal H})$, we derive the metric of spacetime therefrom.Comment: 4 pages' latex-scrip

Wie kann die Mobilität von Studierenden gefördert werden?

Studierendenmobilität stellt ein wichtiges Element des tertiären Bildungssystems dar. Da sich die Studierenden freiwillig für bzw. gegen internationale Mobilität im Zuge des Studiums entscheiden, drängt sich die Frage auf, aufgrund welcher Faktoren diese Entscheidung getroffen wird. Aufbauend auf der Theorie des geplanten Verhaltens (Ajzen, 1988) wird basierend auf den bisherigen Forschungsergebnissen zu diesem Thema ein Modell erstellt, welches das Verhalten der Studierendenmobilität erklären soll. Dazu wurde ein Online-Fragebogen verfasst, der die persönliche Einstellung, die subjektive Norm und Komponenten der subjektiven Verhaltenskontrolle erhob. Alle ordentlich Studierenden der Universität Wien wurden mittels e-Mail gebeten, sich an der Umfrage zu beteiligen. Von den 9 504 Studierende, die den Fragebogen vollständig ausgefüllt hatten, wurden 3 561 Studierende, die entweder nie einen Studienauslandsaufenthalt absolvieren wollen oder die schon einen Studienauslandsaufenthalt absolviert hatten, in die Stichprobe aufgenommen. Mittels binär logistischer Regression wurden das Modell und die daraus resultierenden Hypothesen überprüft. Das Modell konnte großteils bestätigt werden. Faktoren die die Teilnahme an einem Studienauslandsaufenthalt hemmen sind Beziehungsstatus, eigenes Einkommen, informelle und akademische Informiertheit sowie Studienzeitverzögerung. Faktoren die die Teilnahme an einem Studienauslandsaufenthalt fördern sind kulturelle Motive, Karriere-Motive, subjektive Normen, formelle Informiertheit, Offenheit gegenüber interkulturellen Kontakten, Erfahrungen und Stipendium. Für die Variablen, kulturelle Offenheit bezogen auf Freundschaften, Sprachkenntnisse, Studienplan und die gesamten finanziellen Mittel, konnte kein signifikanter Effekt nachgewiesen werden. Aufgrund der großen Stichprobe und der Repräsentativität lassen sich diese Ergebnisse auf die Population der ordentlich Studierenden der Universität Wien verallgemeinern und setzen so einen wesentlichen Schritt zur Erklärung der hemmenden und fördernden Faktoren der Studierendenmobilität

The effect of religion on coming out and the sexual identity formation of 18-30 year olds who self-identify as lesbian, gay, bisexual, or queer : a project based upon an independent investigation

Religion, particularly within Judeo-Christian traditions, is an often cited rationale for rejection of homosexuality and persons who identify as lesbian, gay, bisexual, or queer. Given the socio-cultural influence of religion, catalyzed through the media, legislation, churches, and families, such frequent defamation could be believed to elicit a moral dilemma for an individual contemplating his/her own sexual identity. This effect might be detectable through the process and age of coming out as lesbian, gay, bisexual, or queer. This study sought to investigate the direct impact of a religious upbringing on sexual identity formation and was executed through quantitative analysis with a cross-sectional design utilizing a snowball sample, recruited through social networking websites. The sample was comprised of 60 participants, with 49 completed anonymous, online surveys that included 12 demographic questions, the Lesbian, Gay, and Bisexual Identity Scale (LGBIS) and the Brief Multi-Measure of Religion and Spirituality (BMMRS). The LGBIS measure was modified to include queer identity. While religion was found to have an effect on the coming out process, significant findings either opposed the hypothesis or were found to be, in general, inconclusive. Future research should focus on recruiting a larger and more diverse sample and perhaps utilize different research measures

Spinning cosmic strings: a general class of solutions

In this work, we give a general class of solutions of the spinning cosmic string in Einstein's theory of gravity. After treating same problem in Einstein Cartan (EC) theory of gravity, the exact solution satisfying both exterior and interior space-times representing a spin fluid moving along the symmetry axis is presented in the EC theory. The existence of closed timelike curves in this spacetime are also examined

On the energetics of P-P bond dissociation of sterically strained tetraamino-diphosphanes

The homolytic P-P bond fission in a series of sterically congested tetraaminodiphosphanes (R2N)(2)P-P-(NR2)(2) ({4}(2)-{9}(2), two of which were newly synthesized and fully characterized) into diaminophosphanyl radicals (R2N)(2)P-center dot (4-9) was monitored by VT EPR spectroscopy. Determination of the radical concentration from the EPR spectra permitted to calculate free dissociation energies Delta G(Diss)(295) as well as dissociation enthalpies Delta H-Diss and entropies Delta S-Diss, respectively. Large positive values of Delta G(Diss)(295) indicate that the degree of dissociation is in most cases low, and the concentration of persistent radicals - even if they are spectroscopically observable at ambient temperature - remains small. Appreciable dissociation was established only for the sterically highly congested acyclic derivative {9}(2). Analysis of the trends in experimental data in connection with DFT studies indicate that radical formation is favoured by large entropy contributions and the energetic effect of structural relaxation (geometrical distortions and conformational changes in acyclic derivatives) in the radicals, and disfavoured by attractive dispersion forces. Comparison of the energetics of formation for CC-saturated N-heterocyclic diphosphanes and the 7 pi-radical 3c indicates that the effect of energetic stabilization by pi-electron delocalization in the latter is visible, but stands back behind those of steric and entropic contributions. Evaluation of spectroscopic and computational data indicates that diaminophosphanyl radicals exhibit, in contrast to aminophosphenium cations, no strong energetic preference for a planar arrangement of the (R2N)(2)P unit.Peer reviewe

Spacetime Defects: von K\'arm\'an vortex street like configurations

A special arrangement of spinning strings with dislocations similar to a von K\'arm\'an vortex street is studied. We numerically solve the geodesic equations for the special case of a test particle moving along twoinfinite rows of pure dislocations and also discuss the case of pure spinning defects.Comment: 9 pages, 2figures, CQG in pres