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How much can we save? Impact of different emission scenarios on future snow cover in the Alps
No full textThis study focuses on an assessment of the future snow depth for two larger Alpine catchments. Automatic weather station data from two diverse regions in the Swiss Alps have been used as input for the Alpine3D surface process model to compute the snow cover at a 200m horizontal resolution for the reference period (1999-2012). Future temperature and precipitation changes have been computed from 20 downscaled GCM-RCM chains for three different emission scenarios, including one intervention scenario (2 degrees C target) and for three future time periods (2020-2049, 20452074, 2070-2099). By applying simple daily change values to measured time series of temperature and precipitation, small-scale climate scenarios have been calculated for the median estimate and extreme changes. The projections reveal a decrease in snow depth for all elevations, time periods and emission scenarios. The non-intervention scenarios demonstrate a decrease of about 50% even for elevations above 3000 m. The most affected elevation zone for climate change is located below 1200 m, where the simulations show almost no snow towards the end of the century. Depending on the emission scenario and elevation zone the winter season starts half a month to 1 month later and ends 1 to 3 months earlier in this last scenario period. The resulting snow cover changes may be roughly equivalent to an elevation shift of 500-800 or 700-1000m for the two non-intervention emission scenarios. At the end of the century the number of snow days may be more than halved at an elevation of around 1500m and only 0-2 snow days are predicted in the lowlands. The results for the intervention scenario reveal no differences for the first scenario period but clearly demonstrate a stabilization there-after, comprising much lower snow cover reductions towards the end of the century (ca. 30% instead of 70 %).CRYOSThis article is licensed under a Creative Commons Attribution 4.0 International Licens
Advances in Bias-aware Recommendation on the Web
No full textThe goal of this tutorial is to provide the WSDM community with recent advances on the assessment and mitigation of data and algorithmic bias in recommender systems. We first introduce conceptual foundations, by presenting the state of the art and describing real-world examples of how bias can impact on recommendation algorithms from several perspectives (e.g., ethical and system objectives). The tutorial continues with a systematic showcase of algorithmic countermeasures to uncover, assess, and reduce bias along the recommendation design process. A practical part then provides attendees with implementations of pre-, in-, and post-processing bias mitigation algorithms, leveraging open-source tools and public datasets; in this part, tutorial participants are engaged in the design of bias countermeasures and in articulating impacts on stakeholders. We conclude the tutorial by analyzing emerging open issues and future directions in this rapidly evolving research area (Website: https://biasinrecsys.githublo/wsdm2021).ML4E
Influence of Facial Feedback and Mind Perception During a Cooperative Human-Robot Task in Schizophrenia
No full textRapid progress in the area of humanoid robots offers tremendous possibilities for investigating and improving social competences in people with social deficits, but remains yet unexplored in schizophrenia. In this study, we examined the influence of social feedbacks elicited by a humanoid robot on motor coordination during a human-robot interaction. Twenty-two schizophrenia patients and twenty-two matched healthy controls underwent a collaborative motor synchrony task with the iCub humanoid robot. Results revealed that positive social feedback had a facilitatory effect on motor coordination in the control participants compared to non-social positive feedback. This facilitatory effect was not present in schizophrenia patients, whose social-motor coordination was similarly impaired in social and non-social feedback conditions. Furthermore, patients’ cognitive flexibility impairment and antipsychotic dosing were negatively correlated with patients’ ability to synchronize hand movements with iCub. Overall, our findings reveal that patients have marked difficulties to exploit facial social cues elicited by a humanoid robot to modulate their motor coordination during human-robot interaction, partly accounted for by cognitive deficits and medication. This study opens new perspectives for comprehension of social deficits in this mental disorder.LAS
Peptide mediated formation of hierarchically organized solution and solid state polymer nanostructures
No full textBiologically-inspired peptide sequences have been explored as auxiliaries to mediate self-assembly of synthetic macromolecules into hierarchically organized solution and solid state nanostructures. Peptide sequences inspired by the coiled coil motif and "switch" peptides, which can adopt both amphiphilic α-helical and α-strand conformations, were conjugated to poly(ethylene glycol) (PEG). The solution and solid state self-assembly of these materials was investigated using a variety of spectroscopic, scattering and microscopic techniques. These experiments revealed that the folding and organization properties of the peptide sequences are retained upon conjugation of PEG and that they provide the driving force for the formation of the different nanoscale structures which were observed. The possibility of using defined peptide sequences to direct structure formation of synthetic polymers together with the potential of peptide sequences to induce a specific biological response offers interesting prospects for the development of novel self-assembled and biologically active materials.L
Biexciton kinetics in GaN quantum wells: Time-resolved and time-integrated photoluminescence measurements
No full textWe report on the experimental achievement of narrow ultraviolet excitonic and biexcitonic emission from GaN/AlGaN quantum wells. The very large biexciton binding energy (up to 12 meV) inhibits thermalization between the two species allowing to study the recombination kinetics of the biexciton gas. By performing resonant and nonresonant time resolved measurements, we elucidate the interplay between biexciton formation and exciton acoustic-phonon mediated relaxation within localized states.LASP
Spin Texture of Bi2Se3 Thin Films in the Quantum Tunneling Limit
No full textBy means of spin- and angle-resolved photoelectron spectroscopy we studied the spin structure of thin films of the topological insulator Bi2Se3 grown on InP(111). For thicknesses below six quintuple layers the spin- polarized metallic topological surface states interact with each other via quantum tunneling and a gap opens. Our measurements show that the resulting surface states can be described by massive Dirac cones which are split in a Rashba-like manner due to the substrate induced inversion asymmetry. The inner and the outer Rashba branches have distinct localization in the top and the bottom part of the film, whereas the band apices are delocalized throughout the entire film. Supported by ab initio calculations, our observations help in the understanding of the evolution of the surface states at the topological phase transition and provide the groundwork for the realization of two-dimensional spintronic devices based on topological semiconductors.SCI-SB-H
L'ERACOM à Lausanne (ancienne Ecole complémentaire professionnelle de la Société industrielle et commerciale). Etude patrimoniale
No full textTSA
Correlation of index changes with stress changes in fibers containing UV-written Bragg gratings
No full textStrong correlation between index change and stress change in irradiated optical fibers is reported. The stress increases with fluence. Stress changes and hence index changes seem to be due to a compaction of the fiber coreLOASCI-STI-HLSwiss Federal Inst. of Technol., Lausanne, Switzerland, 5058408, index changes, stress changes, fibers, UV-written Bragg gratings, irradiated optical fibers, fiber core compactio