TY - JOUR A1 - Huber, Albert T1 - The gravitational field of a massless particle on the horizon of a stationary black hole JF - Classical and Quantum Gravity N2 - In this work, the field of a gravitational shockwave generated by a massless point-like particle is calculated at the event horizon of a stationary Kerr–Newman black hole. Using the geometric framework of generalized Kerr–Schild deformations in combination with the spin-coefficient formalism of Newman and Penrose, it is shown that the field equations of the theory, at the event horizon of the black hole, can be reduced to a single linear ordinary differential equation for the so-called profile function of the geometry. This differential relation is solved exactly. Based on the results obtained, a physical interpretation is given for the found shockwave spacetime, and it is clarified how these results lead back to those of previous works on the subject, which deal with the much simpler cases of gravitational shockwaves in static black hole backgrounds. KW - Gravitation Y1 - ER - TY - JOUR A1 - Hoffmann, Michael E. A1 - Kuba, Markus T1 - Logarithmic integrals, zeta values, and tiered binomial coeffcients JF - Monatshefte fuer Mathematik KW - Integrals KW - Binomial KW - Coefficient Y1 - ER - TY - JOUR A1 - Belkacem, Kévin A1 - Kupka, Friedrich A1 - Philidet, Jordan A1 - Samadi, Réza T1 - Surface effects and turbulent pressure. Assessing the Gas-Γ1 and Reduced-Γ1 empirical models. JF - Astronomy & Astrophysics KW - Surface KW - Pressure Y1 - ER - TY - JOUR A1 - Rauer, Johannes Nikolaus A1 - Kroiss, Michael A1 - Kryvinska, Natalia A1 - Engelhardt-Nowitzki, Corinna A1 - Aburaia, Mohamed T1 - Cross-university virtual teamwork as a means of internationalization at home JF - The International Journal of Management Education, Volume 19, Issue 3 KW - Virtual Teamwork Y1 - IS - Issue 3 ER - TY - JOUR A1 - Sinelnikova, Anna A1 - Mandl, Thomas A1 - Agelii, Harald A1 - Grånäs, Oscar A1 - Marklund, Erik G. A1 - Caleman, Carl A1 - De Santis, Emiliano T1 - Protein orientation in time-dependent electric fields: orientation before destruction JF - Biophysical Journal KW - Protein KW - Electric Fields Y1 - IS - Volume 120, Issue 17 SP - 3709 EP - 3717 ER - TY - JOUR A1 - Kuba, Markus A1 - Varvak, Anna T1 - On Path diagrams and Stirling permutations JF - Séminaire Lotharingien de Combinatoire N2 - A permutation can be locally classified according to the four local types: peaks, valleys, double rises and double falls. The corresponding classification of binary increasing trees uses four different types of nodes. Flajolet demonstrated the continued fraction representation of the generating function of local types, using a classical bijection between permutations, binary increasing trees, and suitably defined path diagrams induced by Motzkin paths. The aim of this article is to extend the notion of local types from permutations to k-Stirling permutations (also known as k-multipermutations). We establish a bijection of these local types to node types of (k+1)-ary increasing trees. We present a branched continued fraction representation of the generating function of these local types through a bijection with path diagrams induced by Łukasiewicz paths, generalizing the results from permutations to arbitrary k-Stirling permutations. We further show that the generating function of ordinary Stirling permutation has at least three branched continued fraction representations, using correspondences between non-standard increasing trees, k-Stirling permutations and path diagrams. KW - Kettenbruch KW - Formale Potenzreihe KW - Continued fractions KW - Łukasiewicz paths KW - Path diagrams KW - Stirling permutations KW - Multipermutations KW - Increasing trees Y1 - 2021 IS - B82c (2021) ER - TY - JOUR A1 - Wala, Thomas T1 - Fitness im Büro mit Active Workplace Design JF - Wirtschaft und Management : Schriftenreihe zur wirtschaftswissenschaftlichen Forschung und Praxis N2 - Wissensarbeiter:innen verbringen den überwiegenden Teil ihrer Arbeitszeit sitzend vor dem Computer. Die negativen Folgen von langem Sitzen für die Gesundheit sind bekannt: Zu langes Sitzen bedingt einen niedrigen Kalorienverbrauch, der Stoffwechsel und das Herz-Kreislaufsystem laufen auf Sparflamme. Entsprechend steigt das Risiko für Übergewicht, Diabetes, Bandscheibenvorfall und Herz-Kreislauf- Erkrankungen. Unter den Folgen von langem Sitzen leiden aber nicht nur die betroffenen Mitarbeiter:innen selbst, sondern auch deren Arbeitgeber:innen, weil Mitarbeiter:innen mit einem auf Bewegungsmangel zurückzuführenden reduzierten physischen und psychischen Wohlbefinden weniger produktiv und kreativ arbeiten bzw. aufgrund von Erkrankungen erst gar nicht arbeiten können. Der vorliegende Beitrag zeigt auf, wie Unternehmen durch das Setzen sanfter Bewegungszwänge, den Einsatz dynamischer Arbeitsstationen sowie die Integration niederschwelliger Fitnessmodule in die Bürolandschaft für mehr körperliche Aktivität im Arbeitsalltag sorgen können. KW - Arbeitsplatz KW - Gesundheitsverhalten KW - Fitness Y1 - IS - 31 SP - 47 EP - 58 ER - TY - GEN A1 - Kupka, Friedrich T1 - Improvements to the Short-Characteristics Method in 3D RHD Simulations and some Unsolved Problems in Spectral Line Shapes of A-type Stars KW - Convection KW - Radiative transfer KW - Methods: spectroscopy KW - Methods: numerical Y1 - ER - TY - GEN A1 - Kupka, Friedrich T1 - Improvements in Numerical and Analytical Modelling Techniques to Study the Solar Surface KW - Convection KW - Stars: Sun KW - Methods: numerical KW - Radiative transfer Y1 - ER - TY - GEN A1 - Kupka, Friedrich T1 - Advanced Convection Modelling in Asteroseismology and Stellar Evolution KW - Convection KW - Asteroseismology KW - Stars: evolution Y1 - ER -