Selbstkontrolle und Sensation Seeking: Protektive Faktoren in Stresssituationen?

Leistungssportler stehen einer ganzen Bandbreite von Stressoren gegenüber, die sie mit Hilfe individueller Fähigkeiten und Fertigkeiten zu meistern versuchen. Hierbei wird insbesondere die Fähigkeit zur Selbstkontrolle mit funktionaler Stressbewältigung in Verbindung gesetzt. Auch das Persönlichkeitsmerkmal Sensation Seeking steht mit effektiver Stressregulation in Zusammenhang. Gemäß der zentralen Annahme der vorliegenden Forschungsarbeit wird von einem Stress reduzierenden Einfluss der Selbstkontrolle sowie des Sensation Seeking in akuten Anforderungssituationen ausgegangen. Um dies zu überprüfen, wurden zwei Studien durchgeführt, innerhalb derer insgesamt 120 Probanden hinsichtlich ihrer Stressreaktion auf ein sportspezifisches Kletterparadigma getestet wurden. Die Reaktionen der Probanden wurden mittels psychologischer, physiologischer sowie verhaltensbezogener Maße untersucht. In beiden Studien zeigten sich Interaktionseffekte mit spezifischen physiologischen und psychologischen Parametern. Die Befunde bekräftigen, dass sowohl Selbstkontrolle als auch die Ausprägung in Sensation Seeking von großer Relevanz für das Stresserleben und Wohlergehen von Athleten/-innen sind

Transition from time-variant to static networks: timescale separation in NIMFA SIS epidemics

We extend the N-intertwined mean-field approximation (NIMFA) for the Susceptible-Infectious-Susceptible (SIS) epidemiological process to time-varying networks. Processes on time-varying networks are often analysed under the assumption that the process and network evolution happen on different timescales. This approximation is called timescale separation. We investigate timescale separation between disease spreading and topology updates of the network. We introduce the transition times $\mathrm{\underline{T}}(r)$ and $\mathrm{\overline{T}}(r)$ as the boundaries between the intermediate regime and the annealed (fast changing network) and quenched (static network) regimes, respectively. By analysing the convergence of static NIMFA processes, we analytically derive upper and lower bounds for $\mathrm{\overline{T}}(r)$. Our results provide insights/bounds on the time of convergence to the steady state of the static NIMFA SIS process. We show that, under our assumptions, the upper transition time $\mathrm{\overline{T}}(r)$ is almost entirely determined by the basic reproduction number $R_0$ of the network. The value of the upper transition time $\mathrm{\overline{T}}(r)$ around the epidemic threshold is large, which agrees with the current understanding that some real-world epidemics cannot be approximated with the aforementioned timescale separation.Comment: 30 pages, 13 figure

Improving efficiency and robustness of enhanced assumed strain elements for nonlinear problems

The enhanced assumed strain (EAS) method is one of the most frequently used methods to avoid locking in solid and structural finite elements. One issue of EAS elements in the context of geometrically nonlinear analyses is their lack of robustness in the Newton–Raphson scheme, which is characterized by the necessity of small load increments and large number of iterations. In the present work we extend the recently proposed mixed integration point (MIP) method to EAS elements in order to overcome this drawback in numerous applications. Furthermore, the MIP method is generalized to generic material models, which makes this simple method easily applicable for a broad class of problems. In the numerical simulations in this work, we compare standard strain‐based EAS elements and their MIP improved versions to elements based on the assumed stress method in order to explain when and why the MIP method allows to improve robustness. A further novelty in the present work is an inverse stress‐strain relation for a Neo‐Hookean material model

Independent Promotion of Young Talents in Satellite Development on the Full-Scale Satellite Mission SOURCE

The SOURCE mission is the first student satellite developed at the University of Stuttgart. This unique opportunity for undergraduate and graduate students is made possible by the cooperation between the Institute of Space Systems (IRS) and the Small Satellite Student Society (KSat e.V.

HF-Eigenschaften von Wellenkontaktierungen in Abhängigkeit zur Drehzahl

Innerhalb von Elektromotoren für automobile HV-Anwendungen wird der Bedarf an EMV-Maßnahmen in und um den Elektromotor immer wichtiger. Ein möglicher Ausbreitungspfad für EMV-Störungen auf Systemebene ist hierbei die rotierende Motorwelle [1]. Transientes Schaltverhalten aus dem angeschlossenen Wechselrichter wird hierbei über die Statorwicklungen kapazitiv auf die Motorwelle übertragen und kann sich im schlimmsten Fall unkontrolliert im System ausbreiten (Bild 1). Eine mögliche Maßnahme zur Unterdrückung dieser Störausbreitung ist eine Kontaktierung der rotierenden Motorwelle gegenüber dem Motorgehäuse. Zur Wellenkontaktierung sind Lösungen von unterschiedlichen Herstellern verfügbar

Stroke with unknown time of symptom onset: baseline clinical and magnetic resonance imaging data of the first thousand patients in WAKE-UP (efficacy and safety of mri-based thrombolysis in wake-up stroke: a randomized, doubleblind, placebo-controlled trial)

Background and Purpose—We describe clinical and magnetic resonance imaging (MRI) characteristics of stroke patients with unknown time of symptom onset potentially eligible for thrombolysis from a large prospective cohort. Methods—We analyzed baseline data from WAKE-UP (Efficacy and Safety of MRI-Based Thrombolysis in Wake-Up Stroke: A Randomized, Doubleblind, Placebo-Controlled Trial), an investigator-initiated, randomized, placebo-controlled trial of MRI-based thrombolysis in stroke patients with unknown time of symptom onset. MRI judgment included assessment of the mismatch between visibility of the acute ischemic lesion on diffusion-weighted imaging and fluid-attenuated inversion recovery. Results—Of 1005 patients included, diffusion-weighted imaging and fluid-attenuated inversion recovery mismatch was present in 479 patients (48.0%). Patients with daytime-unwitnessed stroke (n=138, 13.7%) had a shorter delay between symptom recognition and hospital arrival (1.5 versus 1.8 hours; P=0.002), a higher National Institutes of Stroke Scale score on admission (8 versus 6; P<0.001), and more often aphasia (72.5% versus 34.0%; P<0.001) when compared with stroke patients waking up from nighttime sleep. Frequency of diffusion-weighted imaging and fluid-attenuated inversion recovery mismatch was comparable between both groups (43.7% versus 48.7%; P=0.30). Conclusions—Almost half of the patients with unknown time of symptom onset stroke otherwise eligible for thrombolysis had MRI findings making them likely to be within a time window for safe and effective thrombolysis. Patients with daytime onset unwitnessed stroke differ from wake-up stroke patients with regards to clinical characteristics but are comparable in terms of MRI characteristics of lesion age. Clinical Trial Registration—URL: http://www.clinicaltrials.gov. Unique identifier: NCT01525290. URL: https://www.clinicaltrialsregister.eu. Unique identifier: 2011-005906-32

Clinical characteristics of unknown symptom onset stroke patients with and without diffusion-weighted imaging and fluid-attenuated inversion recovery mismatch

Background: Diffusion-weighted imaging (DWI) and fluid-attenuated inversion recovery (FLAIR) mismatch was suggested to identify stroke patients with unknown time of symptom onset likely to be within the time window for thrombolysis. Aims: We aimed to study clinical characteristics associated with DWI-FLAIR mismatch in patients with unknown onset stroke. Methods: We analyzed baseline MRI and clinical data from patients with acute ischemic stroke proven by DWI from WAKE-UP, an investigator-initiated, randomized, placebo-controlled trial of MRI-based thrombolysis in stroke patients with unknown time of symptom onset. Clinical characteristics were compared between patients with and without DWI-FLAIR mismatch. Results: Of 699 patients included, 418 (59.8%) presented with DWI-FLAIR mismatch. A shorter delay between last seen well and symptom recognition (p = 0.0063), a shorter delay between symptom recognition and arrival at hospital (p = 0.0025), and history of atrial fibrillation (p = 0.19) were predictors of DWI-FLAIR mismatch in multivariate analysis. All other characteristics were comparable between groups. Conclusions: There are only minor differences in measured clinical characteristics between unknown symptom onset stroke patients with and without DWI-FLAIR mismatch. DWI-FLAIR mismatch as an indicator of stroke onset within 4.5 h shows no relevant association with commonly collected clinical characteristics of stroke patients