Reduction formula for fermion loops and density correlations of the 1D Fermi gas

Fermion N-loops with an arbitrary number of density vertices N > d+1 in d spatial dimensions can be expressed as a linear combination of (d+1)-loops with coefficients that are rational functions of external momentum and energy variables. A theorem on symmetrized products then implies that divergencies of single loops for low energy and small momenta cancel each other when loops with permuted external variables are summed. We apply these results to the one-dimensional Fermi gas, where an explicit formula for arbitrary N-loops can be derived. The symmetrized N-loop, which describes the dynamical N-point density correlations of the 1D Fermi gas, does not diverge for low energies and small momenta. We derive the precise scaling behavior of the symmetrized N-loop in various important infrared limits.Comment: 14 pages, to be published in Journal of Statistical Physic

The Patenting Behavior of Academic Founders

This study explores why academic entrepreneurs patent their inventions before and after creating a firm. Drawing on start-up data combined with patent data, we specifically examine the impact of five, relatively under-researched factors (scientific field, pace of technological development, technological uncertainty, entrepreneurial orientation, and patent effectiveness. The study shows that some scientific fields, technological uncertainty, and patent effectiveness are positively related to patent propensity, both before and after founding. The effects of pace of technological development and entrepreneurial orientation were timespecific. Our study suggests that patenting by academic entrepreneurs is driven by special rationales and that prior research on full-time scientists and established firms does not necessarily generalize to them. We discuss the implications of our findings both in terms of contribution to the current literature and technology transfer policies. --academic patenting

Patenting rationales of academic entrepreneurs in weak and strong organizational regimes

This study explores why academic entrepreneurs seek patents for spin-off technology in weak organizational regimes (the employee owns her inventions) and strong organizational regimes (the employer, i.e. the university or research organization, owns these inventions). Specifically, we examine organizational and founding team characteristics as alternative explanations. Matched data of academic spin-offs from both contexts combined with patent data show that founding team characteristics (expert knowledge and entrepreneurial orientation) matter in weak, but not strong regimes. In contrast, organizational patenting norms are the key driver of patenting in strong, but not weak regimes. We discuss the implications of our results for the current literature and technology transfer policies

Ein Forschungsüberblick zu Einflussgrößen der Entwicklung technologieorientierter Spin-off-Unternehmen

Technologiebasierte Spin-offs aus öffentlichen Forschungseinrichtungen und privatwirtschaftlichen Unternehmen stellen wichtige Untergruppen junger, innovationsorientierter Unternehmen dar. In diesem Beitrag wird der aktuelle Stand empirischer Forschungsarbeiten bezüglich Einflussfaktoren der Unternehmensentwicklung systematisch dargelegt und diskutiert. Besonderes Augenmerk wird dabei auch auf das methodische Vorgehen und die Messung der untersuchten Einflussfaktoren gelegt. Auf Basis der Literaturanalyse werden übergeordnete Faktoren identifiziert, die für beide Unternehmenstypen einen Einfluss auf deren Entwicklung nehmen. Darüber hinaus werden Lücken der jeweiligen Forschungsbereiche aufgedeckt und zukünftige Forschungsfelder aufgezeigt. Es werden methodische Einschränkungen bestehender Studien diskutiert, aus denen Implikationen für zukünftige Studien zu akademischen und privatwirtschaftlichen Spin-offs abgeleitet werden. Abschließend werden Schwerpunktaufgaben für das Management von Spin-offs herausgestellt. --Spin-offs

Divide and create. A commoning approach to business modeling

Under pressure of declines in the cultural sector, many classical music organizations are reacting similarly with a turn towards predictability regarding both organizational model and artistic output. This paper examines the business model of an organization that utilizes a commoning approach in order to unlock possibilities for artistic innovation

Defining the Prion Type of Fatal Familial Insomnia

Fatal familial insomnia (FFI) belongs to the genetic human transmissible spongiform encephalopathies (TSE), such as genetic Creutzfeldt-Jakob disease (CJD) or Gerstmann-StraeusslerScheinker syndrome (GSS). Here, we analyzed the properties of the pathological prion protein in six FFI cases by Western blot analysis, a protein aggregate stability assay, and aggregate deposition characteristics visualized with the paraffin-embedded tissue blot. While in all cases the unglycosylated fragment in Western blot analysis shared the same size with sporadic CJD prion type 2, the reticular/synaptic deposition pattern of the prion aggregates resembled the ones found in sporadic CJD type 1 (CJD types according to the Parchi classification from 1999). Regarding the conformational stability against denaturation with GdnHCl, FFI prion aggregates resembled CJD type 1 more than type 2. Our results suggest that the size of the proteinase-K-resistant fragments is not a valid criterion on its own. Additional criteria supplying information about conformational differences or similarities need to be taken into account. FFI may resemble a prion type with its own conformation sharing properties partly with type 1 and type 2 prions

Melt-Blowing of Viscoelastic Jets in Turbulent Airflows: Stochastic Modeling and Simulation

In melt-blowing processes mico- and nanofibers are produced by the extrusion of polymeric jets into a directed, turbulent high-speed airflow. Up to now the physical mechanism for the drastic jet thinning is not fully understood, since in the existing literature the numerically computed/predicted fiber thickness differs several orders of magnitude from those experimentally measured. Recent works suggest that this discrepancy might arise from the neglect of the turbulent aerodynamic fluctuations in the simulations. In this paper we confirm this suggestion numerically. Due to the complexity of the process direct numerical simulations of the multiscale-multiphase problem are not possible. Hence, we develop a numerical framework for a growing fiber in turbulent air that makes the simulation of industrial setups feasible. For this purpose we employ an asymptotic viscoelastic model for the fiber. The turbulent effects are taken into account by a stochastic aerodynamic force model where the underlying velocity fluctuations are reconstructed from a $k$-$\epsilon$ turbulence description of the airflow. Our numerical results show the significance of the turbulence on the jet thinning and give fiber diameters of realistic order of magnitude