Disorder-induced coupling of Weyl nodes in WTe2

The finite coupling between Weyl nodes due to residual disorder is investigated by magnetotransport studies in WTe2. The anisotropic scattering of quasiparticles is evidenced from classical and quantum transport measurements. A theoretical approach using the real band structure is developed in order to calculate the dependence of the scattering anisotropy with the correlation length of the disorder. A comparison between theory and experiments reveals a short correlation length in WTe2 (ξ∼5 nm). This result implies a significant coupling between Weyl nodes and other bands. Our study thus shows that a finite intercone scattering rate always exists in weakly disordered type-II Weyl semimetals, such as WTe2, which strongly suppresses topologically nontrivial properties

Bereziskii-Kosterlitz-Thouless transition in the Weyl system \ce{PtBi2}

Symmetry breaking in topological matter became, in the last decade, a key concept in condensed matter physics to unveil novel electronic states. In this work, we reveal that broken inversion symmetry and strong spin-orbit coupling in trigonal \ce{PtBi2} lead to a Weyl semimetal band structure, with unusually robust two-dimensional superconductivity in thin fims. Transport measurements show that high-quality \ce{PtBi2} crystals are three-dimensional superconductors ($T_\text{c}\simeq$600~mK) with an isotropic critical field ($B_\text{c}\simeq$50~mT). Remarkably, we evidence in a rather thick flake (60~nm), exfoliated from a macroscopic crystal, the two-dimensional nature of the superconducting state, with a critical temperature $T_\text{c}\simeq 370$~mK and highly-anisotropic critical fields. Our results reveal a Berezinskii-Kosterlitz-Thouless transition with $T_\text{BKT}\simeq 310$~mK and with a broadening of Tc due to inhomogenities in the sample. Due to the very long superconducting coherence length $\xi$ in \ce{PtBi2}, the vortex-antivortex pairing mechanism can be studied in unusually-thick samples (at least five times thicker than for any other two-dimensional superconductor), making \ce{PtBi2} an ideal platform to study low dimensional superconductivity in a topological semimetal

Novel Echinacea formulations for the treatment of acute respiratory tract infections in adults—A randomized blinded controlled trial

BackgroundEchinacea purpurea has clinical antiviral activity against respiratory viruses and modulates immune functions. In this study, we compared higher doses of new Echinacea formulations with conventional formulations at lower, preventive doses for therapy of respiratory tract infections (RTIs).MethodsIn this randomized, blinded, controlled trial, healthy adults (n = 409) were randomized between November 2018 and January 2019 to one of four Echinacea formulations, which were taken in case of an RTI for up to 10 days. New formulations A (lozenges) and B (spray) delivered an increased dose of 16,800 mg/d Echinacea extract during days 1–3 and 2,240–3,360 mg/d afterward; as controls, conventional formulations C (tablets) and D (drops) delivered a lower daily dose of 2,400 mg, usually taken for prevention. The primary endpoint was time to clinical remission of first RTI episodes based on the Kaplan–Meier analysis of patient-reported, investigator-confirmed, respiratory symptoms assessed for up to 10 days. In a sensitivity analysis, the mean time to remission beyond day 10 was calculated by extrapolating the treatment effects observed on days 7 to 10.ResultsA total of 246 participants (median age 32 years, 78% female participants) were treated for at least one RTI. Recovery by day 10 (complete absence of symptoms) was achieved in 56 and 44% of patients with the new and conventional formulations, respectively, showing a median time to recovery of 10 and 11 days, respectively (p = 0.10 in intention-to-treat analysis, p = 0.07 in per-protocol analysis). In the extrapolated sensitivity analysis, new formulations resulted in a significantly shorter mean time to remission (9.6 vs. 11.0 days, p < 0.001). Among those with an identified respiratory virus, viral clearance until day 10 based on real-time PCR from nasopharyngeal swabs was more frequent with new formulations (70 vs. 53%, p = 0.046). Tolerability and safety (adverse events: 12 vs. 6%, p = 0.19) were good and similar between formulations. There was one severe adverse event with a potential hypersensitivity reaction in a recipient of the novel spray formulation.ConclusionIn adults with acute RTI, new Echinacea formulations with higher doses resulted in faster viral clearance than conventional formulations in prophylactic dosages. The trend for faster clinical recovery was not significant by day 10 but became so upon extrapolation. A dose increase during acute respiratory symptoms might improve the clinical benefits of orally administered Echinacea formulations.Trial registrationThe study was registered in the Swiss National Clinical Trials Portal (SNCTP000003069) and on ClinicalTrials.gov (NTC03812900; URL https://clinicaltrials.gov/ct2/show/NCT03812900?cond=echinacea&draw=3&rank=14)

Genomic history of Neolithic to Bronze Age Anatolia, Northern Levant, and Southern Caucasus

Here, we report genome-wide data analyses from 110 ancient Near Eastern individuals spanning the Late Neolithic to Late Bronze Age, a period characterized by intense interregional interactions for the Near East. We find that 6th millennium BCE populations of North/Central Anatolia and the Southern Caucasus shared mixed ancestry on a genetic cline that formed during the Neolithic between Western Anatolia and regions in today’s Southern Caucasus/Zagros. During the Late Chalcolithic and/or the Early Bronze Age, more than half of the Northern Levantine gene pool was replaced, while in the rest of Anatolia and the Southern Caucasus, we document genetic continuity with only transient gene flow. Additionally, we reveal a genetically distinct individual within the Late Bronze Age Northern Levant. Overall, our study uncovers multiple scales of population dynamics through time, from extensive admixture during the Neolithic period to long-distance mobility within the globalized societies of the Late Bronze Age. Video Abstrac

Integration of behavioral and analytic decision support in electronic negotiations

This paper presents the e-Nego-motion research project which attempts to enhance understanding of effects of and interaction between behavioral and analytic decision support in e-negotiations. Systems providing both kinds of decision support were used in a laboratory experiment. Analyses show that behavioral decision support is requested most often for issues where experienced conflict is high. When consulted early in the negotiation phase, the diagnosis, analysis and advice functions of behavioral support increase the efficiency of agreements. This effect is even stronger if analytic decision support is available to subjects. Additionally, communication patterns influence the quality of negotiations independent of decision support. The more formal offers and counteroffers are exchanged, the higher is the efficiency of outcomes measured by joint utility. Overall, there are no significant differences in the number and quality of agreements between support approaches. Nevertheless, the satisfaction of subjects with process and outcomes reflects the strengths of the support approaches: Subjects with behavioral support are most satisfied with outcomes while subjects with decision support are most satisfied with the negotiation process.8 page(s

Diffusion inter-cônes des fermions de Weyl induite par le désordre dans WTe2_2

International audienceThe finite coupling between Weyl nodes due to residual disorder is investigated by magnetotransport studies in WTe$_2$. The anisotropic scattering of quasiparticles is evidenced from classical and quantum transport measurements. A new theoretical approach using a real band structure is developed to calculate the dependence of the scattering anisotropy with the correlation length of the disorder. A comparison between theory and experiments reveals for the first time a short correlation length in WTe$_2$ ($\xi$~5nm). This result implies a significant coupling between Weyl nodes and other bands, so that inter-node scattering strongly reduces topologically non-trivial properties, such as the chiral anomaly.Le couplage résiduel entre deux cônes de Weyl de chiralité opposée, dû au désordre, est étudié par des mesures de magnéto-transport dans des films minces WTe$_2$. La diffusion anisotrope des quasi-particules est mise en évidence par une comparaison entre le libre parcours moyen élastique et la longueur de transport. Un modèle basé sur la structure de bande précise de WTe2 permet de déterminer la longueur de corrélation du désordre, à partir de la mesure expérimentale de l'anisotropie de diffusion. Cette valeur, très courte (~5nm), suggère un fort couplage entre paires de cônes de Weyl, ce qui devrait fortement réduire l'amplitude de propriétés topologiques, telle que l'anomalie chirale