Polaronic Contributions to Friction in a Manganite Thin Film

Despite the huge importance of friction in regulating movement in all natural and technological processes, the mechanisms underlying dissipation at a sliding contact are still a matter of debate. Attempts to explain the dependence of measured frictional losses at nanoscale contacts on the electronic degrees of freedom of the surrounding materials have so far been controversial. Here, it is proposed that friction can be explained by considering damping of stick-slip pulses in a sliding contact. Based on friction force microscopy studies of La$_{(1-x)}$Sr$_x$MnO$_3$ films at the ferromagnetic-metallic to paramagnetic-polaronic conductor phase transition, it is confirmed that the sliding contact generates thermally-activated slip pulses in the nanoscale contact, and argued that these are damped by direct coupling into phonon bath. Electron-phonon coupling leads to the formation of Jahn-Teller polarons and a clear increase in friction in the high temperature phase. There is no evidence for direct electronic drag on the atomic force microscope tip nor any indication of contributions from electrostatic forces. This intuitive scenario, that friction is governed by the damping of surface vibrational excitations, provides a basis for reconciling controversies in literature studies as well as suggesting possible tactics for controlling friction

Entwicklung von Qualitätsstandards für die Versorgung von Patient*innen mit rheumatoider Arthritis zur Anwendung in Deutschland

Trotz einer qualitativ und strukturell guten Versorgung von Patient*innen mit rheumatoider Arthritis (RA) in Deutschland bestehen weiterhin potenziell behebbare Defizite in der Qualität der Versorgung. Aus diesem Grund hat die Deutsche Gesellschaft für Rheumatologie (DGRh) eine Expert*innengruppe, in der verschiedene Interessengruppen vertreten waren, beauftragt, nationale Qualitätsstandards (QS) mit dem Ziel zu entwickeln, die rheumatologische Versorgung von Patient*innen mit RA in Deutschland qualitativ zu verbessern. QS dienen der Festlegung und quantitativen Messung guter Versorgungsqualität unter dem Vorbehalt von Relevanz und Realisierbarkeit. Als Grundlage für die Entwicklung dienten die kürzlich publizierten Standards von NICE und ASAS und eine systematische Literatursuche. Insgesamt wurden 8 hiermit erstmals veröffentlichte QS konsentiert, die als Grundlage dienen können, die Versorgungsqualität von Patient*innen mit RA in Deutschland zu messen und weiter zu optimieren.Despite a qualitatively and structurally good care of patients with rheumatoid arthritis (RA) in Germany, there are still potentially amendable deficits in the quality of care. For this reason, the German Society for Rheumatology (DGRh) has therefore decided to ask a group of experts including various stakeholders to develop quality standards (QS) for the care of patients with RA in order to improve the quality of care. The QS are used to determine and quantitatively measure the quality of care, subject to relevance and feasibility. The recently published NICE and ASAS standards and a systematic literature search were used as the basis for development. A total of 8 QS, now published for the first time, were approved with the intention to measure and further optimize the quality of care for patients with RA in Germany

Pseudorapidity densities of charged particles with transverse momentum thresholds in pp collisions at √ s = 5.02 and 13 TeV

The pseudorapidity density of charged particles with minimum transverse momentum (pT) thresholds of 0.15, 0.5, 1, and 2 GeV/c is measured in pp collisions at the center of mass energies of √s=5.02 and 13 TeV with the ALICE detector. The study is carried out for inelastic collisions with at least one primary charged particle having a pseudorapidity (η) within 0.8pT larger than the corresponding threshold. In addition, measurements without pT-thresholds are performed for inelastic and nonsingle-diffractive events as well as for inelastic events with at least one charged particle having |η|2GeV/c), highlighting the importance of such measurements for tuning event generators. The new measurements agree within uncertainties with results from the ATLAS and CMS experiments obtained at √s=13TeV.