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Includes a review of the International Labor Conference held in Washington, D.C., 1919, with the draft conventions of this conference, and of the Genoa Conference of 1920; also an account of the organization of the International Labor Office. ; Mode of access: Internet.

10 pags., 9 figs., 3 apps. ; The generation of photons from the vacuum by means of the movement of a mirror is known as the dynamical Casimir effect (DCE). In general, this phenomenon is effectively described by a field with time-dependent boundary conditions. Alternatively, we introduce a microscopic model of the DCE capable of capturing the essential features of the effect with no time-dependent boundary conditions. Besides the field, such a model comprises a subsystem representing the mirror's internal structure. In this work, we study one of the most straightforward mirror systems: a qubit moving in a cavity and coupled to one of the bosonic modes. We find that under certain conditions on the qubit's movement that do not depend on its physical properties, a large number of photons may be generated without changing the qubit state, as should be expected for a microscopic model of the mirror. ; A.A. and C.S. have received financial support through the Postdoctoral Junior Leader Fellowship Programme from la Caixa Banking Foundation (LCF/BQ/LR18/11640005). L.G.-Á. acknowledges support from the Knut and Alice Wallenberg Foundation through the Wallenberg Center for Quantum Technology (WACQT). E.S. acknowledges financial support from Spanish MCIU/AEI/FEDER (PGC2018-095113- B-I00), Basque Government IT986-16, projects QMiCS (820505) and Open- SuperQ (820363) of EU Flagship on Quantum Technologies, EU FET Open Grant Quromorphic, and Shanghai STCSM (Grant No. 2019SHZDZX01-ZX04).

8 pags., 5 figs. ; The quantum perceptron is a fundamental building block for quantum machine learning. This is a multidisciplinary feld that incorporates abilities of quantum computing, such as state superposition and entanglement, to classical machine learning schemes. Motivated by the techniques of shortcuts to adiabaticity, we propose a speed-up quantum perceptron where a control feld on the perceptron is inversely engineered leading to a rapid nonlinear response with a sigmoid activation function. This results in faster overall perceptron performance compared to quasi-adiabatic protocols, as well as in enhanced robustness against imperfections in the controls. ; We acknowledge fnancial support from Spanish Government via PGC2018-095113-B-I00 (MCIU/AEI/FEDER, UE), Basque Government via IT986-16, as well as from QMiCS (820505) and OpenSuperQ (820363) of the EU Flagship on Quantum Technologies, and the EU FET Open Grant Quromorphic (828826). J. C. acknowledges the Ramón y Cajal program (RYC2018- 025197-I) and the EUR2020-112117 Project of the Spanish MICINN,as well as support from the UPV/EHU through the Grant EHUrOPE. X. C. acknowledges NSFC (12075145), SMSTC (2019SHZDZX01-ZX04, 18010500400 and 18ZR1415500), the Program for Eastern Scholar and the Ramón y Cajal program of the Spanish MICINN (RYC-2017-22482). E. T. acknowledges support from Project PGC2018-094792-B-I00 (MCIU/AEI/FEDER,UE), CSIC Research Platform PTI-001, and CAM/FEDER Project No. S2018/TCS-4342 (QUITEMAD-CM). ; Peer reviewed

La resistencia de los materiales a condiciones de intemperie se establece en normas como la NTC 4321-12 del ICONTEC (Método de ensayo para determinar la resistencia al congelamiento de baldosas cerámicas), que sirven para certificar la calidad de los materiales de construcción. Los materiales son sometidos, en cámaras, a decenas de ciclos de hielo y deshielo para verificar la resistencia a la helada; es decir, comprobar la conservación de sus propiedades. Los equipos comerciales para realizar este ensayo están catalogados como robustos y solo sirven para pruebas de un determinado tipo de material, de acuerdo con una norma específica, por lo cual son muy costosos y poco flexibles. En el Centro de Investigación de Materiales Cerámicos (CIMAC-UFPS), se diseñó y construyó un prototipo de equipo, con un sistema de programación y control, que permite efectuar los ensayos de resistencia a la helada a diferentes materiales de construcción, y que adicionalmente sirve para realizar investigación de procesos de cambio en las propiedades de los materiales al ser sometidos a ciclos de congelamiento. El prototipo es tan flexible que permite cambiar parámetros tales como velocidad de enfriamiento y simultáneamente registrar, en tiempo real, la temperatura de las probetas.Palabras clave: NTC 4321-12, ciclos de hielo y deshielo, materiales cerámicos

We consider a superconducting quantum point contact in a circuit quantum electrodynamics setup. We study three different configurations, attainable with current technology, where a quantum point contact is coupled galvanically to a coplanar waveguide resonator. Furthermore, we demonstrate that the strong and ultrastrong coupling regimes can be achieved with realistic parameters, allowing the coherent exchange between a superconducting quantum point contact and a quantized intracavity field. © 2012 American Physical Society. ; We acknowledge funding from Spanish MICINN Juan de la Cierva, FIS2009-12773-C02-01, and FIS2011-28851-C02-02; Basque Government IT472-10 and IT- 366-07; UPV/EHUUFI 11/55; SOLID, CCQED, and PROMISCE European projects. ; Peer Reviewed

We develop energy efficient, continuous microwave schemes to couple electron and nuclear spins, using phase or amplitude modulation to bridge their frequency difference. These controls have promising applications in biological systems, where microwave power should be limited, as well as in situations with high Larmor frequencies due to large magnetic fields and nuclear magnetic moments. These include nanoscale NMR where high magnetic fields achieves enhanced thermal nuclear polarization and larger chemical shifts. Our controls are also suitable for quantum information processors and nuclear polarization schemes. ; E. S. and J. C. acknowledge financial support from Spanish MINECO/FEDER FIS2015-69983-P, Basque Government IT986-16, as well as from QMiCS (820505) and OpenSuperQ (820363) of the EU Flagship on Quantum Technologies. J. C. acknowledges support by the Juan de la Cierva Grant No. IJCI-2016-29681. E. T. and J. J. G. R. acknowledge support from Spanish MINECO/FEDER Project No. FIS2015-70856-P, No. FIS2016-81891-REDT and CAMPRICYT ProjectQUITEMAD þ CMNo. S2013- ICE2801. M. B. P. acknowledges support by the ERC Synergy grant BioQ (Grant No. 319130), the EU project HYPERDIAMOND, the QuantERA project NanoSpin, the BMBF project DiaPol, the state of Baden-Württemberg through bwHPC, and the German Research Foundation (DFG) through Grant No. INST 40/467-1 FUGG. This material is also based upon work supported by the U.S. Department of Energy, Office of Science, Office of Advance Scientific Computing Research (ASCR), Quantum Algorithms Teams project under field work proposal ERKJ335. ; Peer Reviewed

5 pags., 2 figs. ; Quantum illumination consists in shining quantum light on a target region immersed in a bright thermal bath with the aim of detecting the presence of a possible low-reflective object. If the signal is entangled with the receiver, then a suitable choice of the measurement offers a gain with respect to the optimal classical protocol employing coherent states. Here, we tackle this detection problem by using quantum estimation techniques to measure the reflectivity parameter of the object, showing an enhancement in the signal-to-noise ratio up to 3 dB with respect to the classical case when implementing only local measurements. Our approach employs the quantum Fisher information to provide an upper bound for the error probability, supplies the concrete estimator saturating the bound, and extends the quantum illumination protocol to non-Gaussian states. As an example, we show how Schrödinger's cat states may be used for quantum illumination. ; The authors acknowledge support from Spanish MINECO/FEDER Grants No. FIS2015-69983-P and No. FIS2015-70856-P, Basque Government Grant No. IT986-16, and UPV/EHU UFI 11/55 and a PhD grant, CAM Research Network QUITEMAD+, Consejería de Educación, Juventud y Deporte, Comunidad de Madrid (S2013/ICE-2801), and the European Project AQuS (Project No. 640800). The authors thank Giuseppe Vitagliano and Iagoba Apellaniz for useful discussions. ; Peer Reviewed

In order to apply all ideas from quantum optics to the field of quantum circuits, one of the missing ingredients is a high-efficiency single-photon detector. In this work we propose a design for such a device which successfully reaches 100% efficiency with only one absorber. Our photon detector consists of a three-level system (a phase qubit) coupled to a semi-infinite one-dimensional waveguide (a microwave transmission line) which performs highly efficient photodetection in a simplified manner as compared to previous proposals. Using the tools of quantum optics we extensively study the scattering properties of realistic wave packets against this device, thereby computing the efficiency of the detector. We find that the detector has many operating modes, can detect detuned photons, is robust against design imperfections, and can be made broadband by using more than one absorbing element in the design. Many of these ideas could be translated to other single-mode photonic or plasmonic waveguides interacting with three-level atoms or quantum dots. © 2011 American Physical Society. ; This work was supported by Spanish MICINN Project No. FIS2009-10061, and CAM research consortium QUITEMAD Project No. S2009-ESP-1594. B.P. acknowledges funding by a CSIC JAE-PREDOC2009 Grant. G.R. acknowledges funding from the Juan de la Cierva program. G.J. and C.M.W. thank the Swedish Research Council (VR) and European Research Council for funding. E.S. acknowledges funding from Basque Government Grant No. IT472-10, Spanish MICINN Project No. FIS2009-12773-C02-01, the SOLID European project, and the EU CCQED project. ; Peer Reviewed

Thanks to high-precision photometric data legacy from space telescopes like CoRoT and Kepler, the scientific community could detect and characterize the power spectra of hundreds of thousands of stars. Using the scaling relations, it is possible to estimate masses and radii for solar-type pulsators. However, these stars are not the only kind of stellar objects that follow these rules: δ Scuti stars seem to be characterized with seismic indexes such as the large separation (Δν). Thanks to long-duration high-cadence TESS light curves, we analysed more than two thousand of this kind of classical pulsators. In that way, we propose the frequency at maximum power (νmax) as a proper seismic index since it is directly related with the intrinsic temperature, mass and radius of the star. This parameter seems not to be affected by rotation, inclination, extinction or resonances, with the exception of the evolution of the stellar parameters. Furthermore, we can constrain rotation and inclination using the departure of temperature produced by the gravity-darkening effect. This is especially feasible for fast rotators as most of δ Scuti stars seem to be. ; With funding from the Spanish government through the "María de Maeztu Unit of Excellence" accreditation (MDM-2017-0737)

Thanks to high-precision photometric data legacy from space telescopes like CoRoT andKepler, the scientific community could detect and characterize the power spectra of hundreds of thousands of stars. Using the scaling relations, it is possible to estimate masses and radii for solar-type pulsators. However, these stars are not the only kind of stellar objects that follow these rules:delta Scuti stars seem to be characterized with seismic indexes such as the large separation (Delta nu). Thanks to long-duration high-cadence TESS light curves, we analysed more than two thousand of this kind of classical pulsators. In that way, we propose the frequency at maximum power (nu(max)) as a proper seismic index since it is directly related with the intrinsic temperature, mass and radius of the star. This parameter seems not to be affected by rotation, inclination, extinction or resonances, with the exception of the evolution of the stellar parameters. Furthermore, we can constrain rotation and inclination using the departure of temperature produced by the gravity-darkening effect. This is especially feasible for fast rotators as most of delta Scuti stars seem to be. © ESO 2020. ; We also thank the CoRoT, Kepler, and TESS teams whose efforts made these results possible. The CoRoT space mission was developed and operated by CNES, with contributions from Austria, Belgium, Brazil, ESA (RSSD and Science Program), Germany and Spain. Funding for Kepler's Discovery mission is provided by NASA's Science Mission Directorate. Funding for the TESS mission is provided by the NASA Explorer Program. The authors acknowledge the effort made by TASOC WG4 that helped us in our target selection. This publication makes use of VOSA, developed under the Spanish Virtual Observatory project supported by the Spanish MICIU through Grant AyA2017-84089. VOSA has been partially updated by using funding from the European Union's Horizon 2020 Research and Innovation Programme, under Grant Agreement No. 776403 (EXOPLANETS-A). SBF and DB received financial support from the Spanish State Research Agency (AEI) Projects No. ESP2017-87676-C5-1-R and No. MDM-2017-0737 Unidad de Excelencia "Maria de Maeztu"- Centro de Astrobiologia (INTA-CSIC). AM acknowledges funding from the European Union's Horizon 2020 research and innovation program under the Marie Sklodowska-Curie Grant agreement No. 749962 (project THOT). SMR acknowledges financial support from the State Agency for Research of the Spanish MICIU through the "Center of Excellence Severo Ochoa" award to the Instituto de Astrofisica de Andalucia (SEV-2017-0709). JCS and AGH acknowledge funding support from Spanish public funds (including FEDER fonds) for research under project ESP2017-87676-C5-2-R and ESP2017-87676-C5-5-R. JCS also acknowledges support from project RYC-2012-09913 under the "Ramon y Cajal" program of the Spanish Ministry of Science and Education. AGH acknowledges support from "Universidad de Granada" under project E-FQM-041-UGR18 from "Programa Operativo FEDER 2014-2020" programme by "Junta de Andalucia" regional Government. ; Peer reviewed

Existing and upcoming instrumentation is collecting large amounts of astrophysical data, which require efficient and fast analysis techniques. We present a deep neural network architecture to analyze high-resolution stellar spectra and predict stellar parameters such as effective temperature, surface gravity, metallicity, and rotational velocity. With this study, we firstly demonstrate the capability of deep neural networks to precisely recover stellar parameters from a synthetic training set. Secondly, we analyze the application of this method to observed spectra and the impact of the synthetic gap (i.e., the difference between observed and synthetic spectra) on the estimation of stellar parameters, their errors, and their precision. Our convolutional network is trained on synthetic PHOENIX-ACES spectra in different optical and near-infrared wavelength regions. For each of the four stellar parameters, Teff, log g, [M/H], and v sin i, we constructed a neural network model to estimate each parameter independently. We then applied this method to 50 M dwarfs with high-resolution spectra taken with CARMENES (Calar Alto high-Resolution search for M dwarfs with Exo-earths with Near-infrared and optical Échelle Spectrographs), which operates in the visible (520-960 nm) and near-infrared wavelength range (960-1710 nm) simultaneously. Our results are compared with literature values for these stars. They show mostly good agreement within the errors, but also exhibit large deviations in some cases, especially for [M/H], pointing out the importance of a better understanding of the synthetic gap. ; With funding from the Spanish government through the "María de Maeztu Unit of Excellence" accreditation (MDM-2017-0737)

Full list of authors: Baqui, P. O.; Marra, V.; Casarini, L.; Angulo, R.; Díaz-García, L. A.; Hernández-Monteagudo, C.; Lopes, P. A. A.; López-Sanjuan, C.; Muniesa, D.; Placco, V. M.; Quartin, M.; Queiroz, C.; Sobral, D.; Solano, E.; Tempel, E.; Varela, J.; Vílchez, J. M.; Abramo, R.; Alcaniz, J.; Benitez, N. Bonoli, S.; Carneiro, S.; Cenarro, A. J.; Cristóbal-Hornillos, D.; de Amorim, A. L.; de Oliveira, C. M.; Dupke, R.; Ederoclite, A.; González Delgado, R. M.; Marín-Franch, A.; Moles, M.; Vázquez Ramió, H.; Sodré, L.; Taylor, K. ; Context. Future astrophysical surveys such as J-PAS will produce very large datasets, the so-called "big data", which will require the deployment of accurate and efficient machine-learning (ML) methods. In this work, we analyze the miniJPAS survey, which observed about similar to 1 deg(2) of the AEGIS field with 56 narrow-band filters and 4 ugri broad-band filters. The miniJPAS primary catalog contains approximately 64 000 objects in the r detection band (mag(AB)less than or similar to 24), with forced-photometry in all other filters.Aims. We discuss the classification of miniJPAS sources into extended (galaxies) and point-like (e.g., stars) objects, which is a step required for the subsequent scientific analyses. We aim at developing an ML classifier that is complementary to traditional tools that are based on explicit modeling. In particular, our goal is to release a value-added catalog with our best classification.Methods. In order to train and test our classifiers, we cross-matched the miniJPAS dataset with SDSS and HSC-SSP data, whose classification is trustworthy within the intervals 15 <= r <= 20 and 18.5 <= r <= 23.5, respectively. We trained and tested six different ML algorithms on the two cross-matched catalogs: K-nearest neighbors, decision trees, random forest (RF), artificial neural networks, extremely randomized trees (ERT), and an ensemble classifier. This last is a hybrid algorithm that combines artificial neural networks and RF with the J-PAS stellar and galactic loci classifier. As input for the ML algorithms we used the magnitudes from the 60 filters together with their errors, with and without the morphological parameters. We also used the mean point spread function in the r detection band for each pointing.Results. We find that the RF and ERT algorithms perform best in all scenarios. When the full magnitude range of 15 <= r <= 23.5 is analyzed, we find an area under the curve AUC=0.957 with RF when photometric information alone is used, and AUC=0.986 with ERT when photometric and morphological information is used together. When morphological parameters are used, the full width at half maximum is the most important feature. When photometric information is used alone, we observe that broad bands are not necessarily more important than narrow bands, and errors (the width of the distribution) are as important as the measurements (central value of the distribution). In other words, it is apparently important to fully characterize the measurement.Conclusions. ML algorithms can compete with traditional star and galaxy classifiers; they outperform the latter at fainter magnitudes (r greater than or similar to 21). We use our best classifiers, with and without morphology, in order to produce a value-added catalog. © ESO 2021 ; POB thanks, for financial support, the Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior - Brasil (CAPES) - Finance Code 001. VM thanks CNPq (Brazil) and FAPES (Brazil) for partial financial support. This project has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No 888258. LADG is supported by the Ministry of Science and Technology of Taiwan (grant MOST 106-2628-M-001-003-MY3), and by the Academia Sinica (grant AS-IA-107-M01). ES has been partly supported by the Spanish State Research Agency (AEI) Projects AYA2017-84089 and MDM-2017-0737 at Centro de Astrobiologia (CSIC-INTA), Unidad de Excelencia Maria de Maeztu. MQ is supported by the Brazilian research agencies CNPq and FAPERJ. RGD acknowledges financial support from the State Agency for Research of the Spanish MCIU through the "Center of Excellence Severo Ochoa" award to the Instituto de Astrofisica de Andalucia (SEV-2017-0709) and through the projects AyA2016-77846-P and PID2019-109067GB-100. LS acknowledges support from Brazilian agencies CNPq (grant 304819/2017-4) and FAPESP (grant 2012/00800-4). This work made use of the Virgo Cluster at Cosmo-ufes/UFES, which is funded by FAPES and administrated by Renan Alves de Oliveira. Based on observations made with the JST/T250 telescope and PathFinder camera for the miniJPAS project at the Observatorio Astrofisico de Javalambre (OAJ), in Teruel, owned, managed, and operated by the Centro de Estudios de Fisica del Cosmos de Aragon (CEFCA). We acknowledge the OAJ Data Processing and Archiving Unit (UPAD) for reducing and calibrating the OAJ data used in this work. Funding for OAJ, UPAD, and CEFCA has been provided by the Governments of Spain and Aragon through the Fondo de Inversiones de Teruel; the Aragon Government through the Research Groups E96, E103, and E16_17R; the Spanish Ministry of Science, Innovation and Universities (MCIU/AEI/FEDER, UE) with grant PGC2018-097585-B-C21; the Spanish Ministry of Economy and Competitiveness (MINECO/FEDER, UE) under AYA2015-66211-C2-1-P, AYA2015-66211-C2-2, AYA2012-30789, and ICTS-2009-14; and European FEDER funding (FCDD10-4E-867, FCDD13-4E2685). Based on data from ALHAMBRA Data Access Service the at CAB (CSIC-INTA). Funding for the DEEP2 Galaxy Redshift Survey has been provided by NSF grants AST-95-09298, AST-0071048, AST-0507428, and AST0507483 as well as NASA LTSA grant NNG04GC89G. The Hyper SuprimeCam (HSC) collaboration includes the astronomical communities of Japan and Taiwan, and Princeton University. The HSC instrumentation and software were developed by the National Astronomical Observatory of Japan (NAOJ), the Kavli Institute for the Physics and Mathematics of the Universe (Kavli IPMU), the University of Tokyo, the High Energy Accelerator Research Organization (KEK), the Academia Sinica Institute for Astronomy and Astrophysics in Taiwan (ASIAA), and Princeton University. Funding was contributed by the FIRST program from the Japanese Cabinet O ffice, the Ministry of Education, Culture, Sports, Science and Technology (MEXT), the Japan Society for the Promotion of Science (JSPS), Japan Science and Technology Agency (JST), the Toray Science Foundation, NAOJ, Kavli IPMU, KEK, ASIAA, and Princeton University. This paper makes use of software developed for the Large Synoptic Survey Telescope. We thank the LSST Project for making their code available as free software at dm.lsst.org. This paper is based [in part] on data collected at the Subaru Telescope and retrieved from the HSC data archive system, which is operated by Subaru Telescope and Astronomy Data Center (ADC) at National Astronomical Observatory of Japan. Dpart carried out with the cooperation of Center for Computational Astrophysics (CfCA), National Astronomical Observatory of Japan. Funding for SDSS-III has been provided by the Alfred P. Sloan Foundation, the Participating Institutions, the National Science Foundation, and the U.S. Department of Energy Office of Science. The SDSS-III website is sdss3.org. SDSS-III is managed by the Astrophysical Research Consortium for the Participating Institutions of the SDSS-III Collaboration including the University of Arizona, the Brazilian Participation Group, Brookhaven National Laboratory, Carnegie Mellon University, University of Florida, the French Participation Group, the German Participation Group, Harvard University, the Instituto de Astrofisica de Canarias, the Michigan State/Notre Dame/JINA Participation Group, Johns Hopkins University, Lawrence Berkeley National Laboratory, Max Planck Institute for Astrophysics, Max Planck Institute for Extraterrestrial Physics, New Mexico State University, New York University, Ohio State University, Pennsylvania State University, University of Portsmouth, Princeton University, the Spanish Participation Group, University of Tokyo, University of Utah, Vanderbilt University, University of Virginia, University of Washington, and Yale University. ; Peer reviewed

Context. The relevance of M dwarfs in the search for potentially habitable Earth-sized planets has grown significantly in the last years. Aims. In our on-going effort to comprehensively and accurately characterise confirmed and potential planet-hosting M dwarfs, in particular for the CARMENES survey, we have carried out a comprehensive multi-band photometric analysis involving spectral energy distributions, luminosities, absolute magnitudes, colours, and spectral types, from which we have derived basic astrophysical parameters. Methods. We have carefully compiled photometry in 20 passbands from the ultraviolet to the mid-infrared, and combined it with the latest parallactic distances and close-multiplicity information, mostly from Gaia DR2, of a sample of 2479 K5 V to L8 stars and ultracool dwarfs, including 2210 nearby, bright M dwarfs. For this, we made extensive use of Virtual Observatory tools. Results. We have homogeneously computed accurate bolometric luminosities and effective temperatures of 1843 single stars, derived their radii and masses, studied the impact of metallicity, and compared our results with the literature. The over 40 000 individually inspected magnitudes, together with the basic data and derived parameters of the stars, individual and averaged by spectral type, have been made public to the astronomical community. In addition, we have reported 40 new close multiple systems and candidates (ρ < 3.3 arcsec) and 36 overluminous stars that are assigned to young Galactic populations. Conclusions. In the new era of exoplanet searches around M dwarfs via transit (e.g. TESS, PLATO) and radial velocity (e.g. CARMENES, NIRPS+HARPS), this work is of fundamental importance for stellar and therefore planetary parameter determination. ; With funding from the Spanish government through the "María de Maeztu Unit of Excellence" accreditation (MDM-2017-0737)