University of Konstanz
KOPS - The Institutional Repository of the University of KonstanzNot a member yet
31050 research outputs found
Sort by
Swarming transitions of self-propelled particles with anisotropic social interactions
No full textCollective motion in living systems is observed across many scales, from bacterial colonies to insect swarms, fish schools, and bird flocks. In all cases the motility of individual cells or organisms both is influenced by and, in turn, influences the motion of others. While the mechanisms by which individuals sense and respond to others differ greatly among species, simplified models that capture general principles of social interactions, such as the Vicsek model, have proved insightful. Here we introduce anisotropic sensory perception (a feature common to many animal species) into the Vicsek model in order to evaluate how this feature impacts collective motion. We find that, when the anisotropy >0, meaning individuals are more influenced by neighbors ahead of them than those behind them, as the anisotropy becomes stronger, the swarming transition changes from the weak first-order transition observed for populations with isotropic perception to a stronger (i.e., more abrupt) first-order transition. Moreover, the critical noise threshold to achieve ordered motion decreases if increases from zero to positive values. By contrast, when the anisotropy <0, indicating individuals pay more attention to rearward neighbors, as the anisotropy becomes stronger, the order-disorder transition remains first order (at the thermodynamic limit) but becomes increasingly weak (less abrupt), and the critical noise threshold required to reach ordered motion increases slightly. An even simpler front-back semicircle model and an anisotropic model with vectorial noise are employed to further validate the respective roles those ahead and behind play in the emergence of collective motion. Taken together, our results demonstrate that the contribution of neighboring individuals to the collective motion in such particle systems significantly depends on their relative position to the focal particle. Frontal neighbors primarily enhance the strength of the first-order transition, whereas rearward neighbors progressively weaken it.publishe
Organising More ERUA Open Science Meet-Ups : New Methods and Experiences from the Re:ERUA Project
No full textAs we have established in Organising the ERUA Open Science Meet-Ups, the field of Open Science is subject to constant change and expansion. To stay up to date, exchange is paramount – not only within universities, but also within larger spheres such as academic alliances. To this end, the Re:ERUA project (research trajectory of the European Reform University Alliance) developed an innovative virtual format of Open Science-related exchange called ERUA Open Science Meet-Ups. In Organising the ERUA Open Science Meet-Ups, we looked at how we got the programme going and which lessons we learned on the way. Around two years and 19 meet-ups later, we shall revisit the format, discussing how we developed the format further into a standard structure that shapes most of the 19 more recent meet-ups. Analysing this structure’s individual components as well as the 19 meet-ups’ individual scopes and our promotion-related measures, we shall draw conclusions, shedding light on our experiences and learnings, hoping that this publication may serve as a means of inspirations for others who may be interested in setting up like-minded formats. In this vein, this publication serves as a follow-up to the scope discussed in Organising the ERUA Open Science Meet-Ups.publishe
Dynamical renormalization of the magnetic excitation spectrum via high-momentum nonlinear magnonics
No full textSustaining the growth of the data volume generated by artificial intelligence and the internet of things demands to develop schemes for data storage and processing operating at terahertz frequencies, unrestrained by thermal throttling. The optical drive of coherent magnetic collective excitations, namely magnons, represents a promising route. The ability to arbitrarily and nonthermally increase the magnon frequencies with laser pulses could enable this progress. However, this effect has not been reported to date. To achieve it, here, we explore the optical resonant excitation of high-momentum magnons, which experimentally are observed to couple to low-momentum magnons, modifying the frequencies and amplitudes thereof. This evidence, not caused by laser heating, is explained with a resonant light-scattering mechanism coupling high- and low-momentum eigenmodes across momentum space. Our results disclose routes to inducing instabilities and phase transitions via mode softening and potentially even light-driven Bose-Einstein condensation of magnons and superconductivity mediated by high-momentum spin-fluctuations.publishe
Blow-up for hyperbolized compressible Navier-Stokes equations
No full textThis work reports on initial value problems to hyperbolized compressible Navier-Stokes equations. Local existence and global existence for small data are addressed as well as singular limits for vanishing relaxation parameters. Then blow-up results for one- and multi-dimensional models are presented using ideas from T.C. Sideris from the 1980s.publishe
Fast Track to Europe : The Integration of the German Democratic Republic into the European Community
No full textpublishe
A preliminary study on the role of personal history of infectious and parasitic diseases on self-reported health across countries
No full textObjectives
Infectious diseases are often associated with decline in quality of life. The aim of this study is to analyze the relationship between personal history of communicable, i.e., infectious and parasitic diseases and self-rated health.
Study design
Secondary analysis of a large dataset multi-country observational study.
Methods
We used a four-pronged analysis approach to investigate whether personal history of infectious and parasitic diseases is related to self-reported health, measured with a single item.
Results
Three of the four analyses found a small positive effect on self-reported health among those reporting a history of pathogen exposure. The meta-analysis found no support but large heterogeneity that was not reduced by two classifications of countries.
Conclusion
Personal history of infectious and parasitic diseases does not reduce self-reported health across a global sample.publishe
Immunoproteasome subunits are novel signatures for predicting efficacy of immunotherapy in muscle invasive bladder cancer
No full textBackground:
How to select muscle-invasive bladder cancer (MIBC) patients who are sensitive to immunotherapy is an unmet medical need. This study aimed to explore the role of immunoproteasome subunits as a novel signature for predicting efficacy of immunotherapy in MIBC.
Methods:
The expression profile of immunoproteasome subunits of MIBC and normal tissues was evaluated from data of The Cancer Genome Atlas (TCGA) and of the Chongqing University Cancer Hospital (CQUCH) cohort. Survival analysis and response to immunotherapy was further explored and compared between immunoproteasome subunitshigh and immunoproteasome subunitslow MIBC patients in the TCGA, the CQUCH and the IMvigor210 cohort. The association of the expression of immunoproteasome subunits with immune checkpoint molecules and the tumor immune microenvironment was explored by immunohistochemistry staining and bioinformatic analysis in MIBC of these three cohorts.
Results:
The expression of the immunoproteasome subunits PSMB8, PSMB9 and PSMB10 was significantly upregulated in MIBC. MIBC patients with high expression of immunoproteasome subunits, especially high expression of PSMB9, showed a trend of prolonged overall and progression free survival, which was further significantly improved in response to immunotherapy. Bioinformatics and immunohistochemistry staining revealed a positive correlation of the expression of immunoproteasome subunits with the expression of immune checkpoint molecules, with T cell activation and with T cell-mediated cytotoxicity.
Conclusions:
Immunoproteasome subunits, in particular PSMB9, are immune microenvironment-related molecules of MIBC and are promising signatures for survival prediction in response to immunotherapy of MIBC.publishe
Line-Graph Qubit Routing
No full textOne limitation of current quantum hardware is the restricted connectivity between qubits, as described by the hardware’s coupling graph. To overcome this limitation, efficient qubit routing strategies are necessary. We introduce line-graph qubit routing, which routes circuits defined on line graphs to hardware with a heavy coupling graph. We implement line-graph qubit routing and demonstrate its effectiveness in mapping quantum circuits defined kagome, checkerboard, and shuriken lattices to hardware with heavy-hex, heavy-square, and heavy-square-octagon coupling graphs, respectively. Benchmarking shows the ability of line-graph qubit routing to outperform established general-purpose methods in a fraction of the computational time, while offering a depth reduction by up to a factor of 5. Line-graph qubit routing has direct applications in the quantum simulation of lattice-based models, serves as a suitable benchmark for other routing methods, and aids the exploration of the capabilities of near-term quantum hardware.publishe