Limits to the analogue Hawking temperature in a Bose-Einstein condensate

Quasi-one dimensional outflow from a dilute gas Bose-Einstein condensate reservoir is a promising system for the creation of analogue Hawking radiation. We use numerical modeling to show that stable sonic horizons exist in such a system under realistic conditions, taking into account the transverse dimensions and three-body loss. We find that loss limits the analogue Hawking temperatures achievable in the hydrodynamic regime, with sodium condensates allowing the highest temperatures. A condensate of 30,000 atoms, with transverse confinement frequency omega_perp=6800*2*pi Hz, yields horizon temperatures of about 20 nK over a period of 50 ms. This is at least four times higher than for other atoms commonly used for Bose-Einstein condensates.Comment: 9 pages, 4 figures, replaced with published versio

Enhancing resonant circular-section haloscopes for dark matter axion detection: approaches and limitations in volume expansion

Haloscopes, microwave resonant cavities utilized in detecting dark matter axions within powerful static magnetic fields, are pivotal in modern astrophysical research. This paper delves into the realm of cylindrical geometries, investigating techniques to augment volume and enhance compatibility with dipole or solenoid magnets. The study explores volume constraints in two categories of haloscope designs: those reliant on single cavities and those employing multicavities. In both categories, strategies to increase the expanse of elongated structures are elucidated. For multicavities, the optimization of space within magnets is explored through 1D configurations. Three subcavity stacking approaches are investigated, while the foray into 2D and 3D geometries lays the groundwork for future topological developments. The results underscore the efficacy of these methods, revealing substantial room for progress in cylindrical haloscope design. Notably, an elongated single cavity design attains a three-order magnitude increase in volume compared to a WC-109 standard waveguide-based single cavity. Diverse prototypes featuring single cavities, 1D, 2D, and 3D multicavities highlight the feasibility of leveraging these geometries to magnify the volume of tangible haloscope implementations

Tratamiento artroscópico de las roturas masivas del manguito rotador

La reparación artroscópica de las roturas masivas del manguito rotador (RMMR) es un procedimiento técnicamente exigente, que requiere de una indicación correcta, una buena técnica artroscópica y un adecuado tratamiento rehabilitador. El estudio clínico del paciente y las características de la lesión del manguito son fundamentales para establecer el plan estratégico y terapéutico, que debe incluir desde el tratamiento no quirúrgico hasta la reparación artroscópica, transferencias tendinosas artroscópicas, espaciadores subacromiales o artroplastias de hombro. La reparación artroscópica se establece en pacientes con roturas masivas reparables y sin degeneración grasa del manguito, las transferencias tendinosas se indican en pacientes jóvenes con importantes exigencias funcionales que presentan roturas masivas irreparables y los espaciadores subacromiales y las artroplastias de hombro para roturas irreparables en pacientes con baja demanda funcionalThe arthroscopic repair of a massive rotator cuff tear, is a technically demanding procedure. It requires correct indications, good arthroscopic skills and a proper rehabilitation program. The clinical study of the patient and the instances of the rotator cuff injury, are fundamental to determine a correct therapeutic strategy. This strategy should consider every option from non-surgical to arthroscopic repair, tendon transfers, subacromial spreaders or shoulder arthroplasties. The arthroscopic repair is the standard treatment in patients with massive repairable tears and with no fatty degeneration of the affected muscle. Meanwhile, the tendon transfers are indicated in young patients with highly functional demands that comprehend irreparable massive tears. The spreaders or subacromial balloons and the shoulder prosthesis are performed in irreparable tears in low functional demand patients

The PL diagram for δ\delta Sct stars: back in business as distance estimators

In this work, we focus on the period-luminosity relation (PLR) of $\delta$ Sct stars, in which mode excitation and selection mechanisms are still poorly constrained, and whose structure and oscillations are affected by rotation. We review the PLRs in the recent literature, and add a new inference from a large sample of $\delta$ Sct. We highlight the difficulty in identifying the fundamental mode and show that rotation-induced surface effects can impact the measured luminosities, explaining the broadening of the PLR. We derive a tight relation between the low-order large separation and the fundamental radial mode frequency (F0) that holds for rotating stars, thus paving the way towards mode identification. We show that the PLRs we obtain for different samples are compatible with each other and with the recent literature, and with most observed $\delta$ Sct stars when taking rotation effects into account. We also find that the highest-amplitude peak in the frequency spectrum corresponds to the fundamental mode in most $\delta$ Sct, thus shedding some light on their elusive mode selection mechanism.Comment: 10 pages, 5 figures, 1 table, IAU conference proceedin

Dating young open clusters using delta Scuti stars. Results for Trumpler 10 and Praesepe

Aims. The main goal of this work is to date young open clusters using $\delta$ Sct stars. Seismic indices such as the large separation and the frequency at maximum power can help to constrain the models to better characterise the stars. We propose a reliable method to identify some radial modes, which gives us greater confidence in the constrained models. Methods. We extract the frequency content of a sample of $\delta$ Sct stars belonging to the same open cluster. We estimate the low-order large separation by means of different techniques and the frequency at maximum power for each member of the sample. We use a grid of models built with the typical parameters of $\delta$ Sct stars, including mass, metallicity and rotation as independent variables, and determine the oscillation modes. We select the observed frequencies whose ratios match those of the models. Once we find a range of radial modes matching the observed frequencies, mainly the fundamental mode, we add it to the other seismic parameters to derive the stellar age. Assuming star groups have similar chemistry and age, we estimate their mean age by computing a weighted probability density function fit to the age distribution of the seismically constrained models. Results. We estimate the age of Trumpler 10 to be $30_{-20}{+30}$ Myr, and that of Praesepe to be $580 \pm 230$ Myr. In this latter case, we find two apparent populations of $\delta$ Sct stars in the same cluster, one at $510 \pm 140$ Myr and another at $890 \pm 140$ Myr. This may be due to two different formation events, different rotational velocities of the members in our sample of stars (as rapid rotation may modify the observed large separation), or to membership of unresolved binary systems.Comment: 20 pages, 25 figure, uses the open-source code MultiModes (see https://github.com/davidpamos/MultiModes). It will be published in A&

Interventions of computerized psychotherapies for depression in Primary Care in Spain

Currently, depression is a global health problem recognized by the WHO. The prevalence of this pathology in Primary Care is estimated at 19.5% worldwide, and 20.2% in Spain. In addition, the current intervention policies and protocols involve significant costs, both personal and economic, for people suffering from this disorder, as well as for society in general. On the other hand, the relapse rates after pharmacological interventions that are currently applied and the lack of effective specialized attention in mental health services reflect the need to develop new therapeutic strategies that are more accessible and profitable. Therefore, one of the proposals that are being investigated in different parts of the world is the design and evaluation of therapeutic protocols applied through Information and Communication Technologies, especially through the Internet and computer programs. The objective of this work was to present the current situation in Spain regarding the use of these interventions for the treatment of depression in Primary Care. The main conclusion is that although there is scientific evidence on the effectiveness of these programs, there are still important barriers that hinder their application in the public system, and also the need to develop implementation studies that facilitate the transition from research to clinical practice

Painlev\'e-Gullstrand synchronizations in spherical symmetry

A Painlev\'e-Gullstrand synchronization is a slicing of the space-time by a family of flat spacelike 3-surfaces. For spherically symmetric space-times, we show that a Painlev\'e-Gullstrand synchronization only exists in the region where $(dr)^2 \leq 1$, $r$ being the curvature radius of the isometry group orbits ($2$-spheres). This condition says that the Misner-Sharp gravitational energy of these 2-spheres is not negative and has an intrinsic meaning in terms of the norm of the mean extrinsic curvature vector. It also provides an algebraic inequality involving the Weyl curvature scalar and the Ricci eigenvalues. We prove that the energy and momentum densities associated with the Weinberg complex of a Painlev\'e-Gullstrand slice vanish in these curvature coordinates, and we give a new interpretation of these slices by using semi-metric Newtonian connections. It is also outlined that, by solving the vacuum Einstein's equations in a coordinate system adapted to a Painlev\'e-Gullstrand synchronization, the Schwarzschild solution is directly obtained in a whole coordinate domain that includes the horizon and both its interior and exterior regions.Comment: 16 page

Dynamically tunable transformation thermodynamics

Recently, the introduction of transformation thermodynamics has provided a way to design thermal media that alter the flow of heat according to any spatial deformation, enabling the construction of novel devices such as thermal cloaks or concentrators. However, in its current version, this technique only allows static deformations of space. Here, we develop a space-time theory of transformation thermodynamics that incorporates the possibility of performing time-varying deformations. This extra freedom greatly widens the range of achievable effects, providing an additional degree of control for heat management applications. As an example, we design a reconfigurable thermal cloak that can be opened and closed dynamically, therefore being able to gradually adjust the temperature distribution of a given region.C G-M acknowledges support from Generalitat Valenciana through the VALi+d postdoctoral program (exp APOSTD/2014/044).García Meca, C.; Barceló, C. (2016). Dynamically tunable transformation thermodynamics. Journal of Optics. 18(4):044026-1-044026-5. https://doi.org/10.1088/2040-8978/18/4/044026S044026-1044026-5184Guenneau, S., Amra, C., & Veynante, D. (2012). Transformation thermodynamics: cloaking and concentrating heat flux. Optics Express, 20(7), 8207. doi:10.1364/oe.20.008207Schittny, R., Kadic, M., Guenneau, S., & Wegener, M. (2013). Experiments on Transformation Thermodynamics: Molding the Flow of Heat. Physical Review Letters, 110(19). doi:10.1103/physrevlett.110.195901McCall, M. W., Favaro, A., Kinsler, P., & Boardman, A. (2011). A spacetime cloak, or a history editor. Journal of Optics, 13(2), 029501-029501. doi:10.1088/2040-8978/13/2/029501Cummer, S. A., & Thompson, R. T. (2010). Frequency conversion by exploiting time in transformation optics. Journal of Optics, 13(2), 024007. doi:10.1088/2040-8978/13/2/024007García-Meca, C., Carloni, S., Barceló, C., Jannes, G., Sánchez-Dehesa, J., & Martínez, A. (2013). Analogue Transformations in Physics and their Application to Acoustics. Scientific Reports, 3(1). doi:10.1038/srep02009García-Meca, C., Carloni, S., Barceló, C., Jannes, G., Sánchez-Dehesa, J., & Martínez, A. (2014). Space–time transformation acoustics. Wave Motion, 51(5), 785-797. doi:10.1016/j.wavemoti.2014.01.008Kinsler, P., & McCall, M. W. (2014). Transformation devices: Event carpets in space and space-time. Physical Review A, 89(6). doi:10.1103/physreva.89.063818Kinsler, P., & McCall, M. W. (2013). Cloaks, editors, and bubbles: applications of spacetime transformation theory. Annalen der Physik, 526(1-2), 51-62. doi:10.1002/andp.201300164Leonhardt, U., & Philbin, T. G. (2006). General relativity in electrical engineering. New Journal of Physics, 8(10), 247-247. doi:10.1088/1367-2630/8/10/247Guenneau, S., & Puvirajesinghe, T. M. (2013). Fick’s second law transformed: one path to cloaking in mass diffusion. Journal of The Royal Society Interface, 10(83), 20130106. doi:10.1098/rsif.2013.0106Guenneau, S., Petiteau, D., Zerrad, M., Amra, C., & Puvirajesinghe, T. (2015). Transformed Fourier and Fick equations for the control of heat and mass diffusion. AIP Advances, 5(5), 053404. doi:10.1063/1.4917492García-Meca, C., Carloni, S., Barceló, C., Jannes, G., Sánchez-Dehesa, J., & Martínez, A. (2014). Analogue transformation acoustics and the compression of spacetime. Photonics and Nanostructures - Fundamentals and Applications, 12(4), 312-318. doi:10.1016/j.photonics.2014.05.001Schittny, R., Kadic, M., Buckmann, T., & Wegener, M. (2014). Invisibility cloaking in a diffusive light scattering medium. Science, 345(6195), 427-429. doi:10.1126/science.1254524Chester, M. (1963). Second Sound in Solids. Physical Review, 131(5), 2013-2015. doi:10.1103/physrev.131.2013Ali, Y. M., & Zhang, L. C. (2005). Relativistic heat conduction. International Journal of Heat and Mass Transfer, 48(12), 2397-2406. doi:10.1016/j.ijheatmasstransfer.2005.02.003López Molina, J. A., Rivera, M. J., & Berjano, E. (2014). Fourier, hyperbolic and relativistic heat transfer equations: a comparative analytical study. Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences, 470(2172), 20140547. doi:10.1098/rspa.2014.0547Christov, C. I., & Jordan, P. M. (2005). Heat Conduction Paradox Involving Second-Sound Propagation in Moving Media. Physical Review Letters, 94(15). doi:10.1103/physrevlett.94.154301Cho, J., Losego, M. D., Zhang, H. G., Kim, H., Zuo, J., Petrov, I., … Braun, P. V. (2014). Electrochemically tunable thermal conductivity of lithium cobalt oxide. Nature Communications, 5(1). doi:10.1038/ncomms5035Ihlefeld, J. F., Foley, B. M., Scrymgeour, D. A., Michael, J. R., McKenzie, B. B., Medlin, D. L., … Hopkins, P. E. (2015). Room-Temperature Voltage Tunable Phonon Thermal Conductivity via Reconfigurable Interfaces in Ferroelectric Thin Films. Nano Letters, 15(3), 1791-1795. doi:10.1021/nl504505

Non-linear models for black carbon exposure modelling using air pollution datasets

Black carbon (BC) is a product of incomplete combustion, present in urban aerosols and sourcing mainly from road traffic. Epidemiological evidence reports positive associations between BC and cardiovascular and respiratory disease. Despite this, BC is currently not regulated by the EU Air Quality Directive, and as a result BC data are not available in urban areas from reference air quality monitoring networks in many countries. To fill this gap, a machine learning approach is proposed to develop a BC proxy using air pollution datasets as an input. The proposed BC proxy is based on two machine learning models, support vector regression (SVR) and random forest (RF), using observations of particle mass and number concentrations (N), gaseous pollutants and meteorological variables as the input. Experimental data were collected from a reference station in Barcelona (Spain) over a 2 year period (2018-2019). Two months of additional data were available from a second urban site in Barcelona, for model validation. BC concentrations estimated by SVR showed a high degree of correlation with the measured BC concentrations (R-2 = 0.828) with a relatively low error (RMSE = 0.48 mu g/m3). Model performance was dependent on seasonality and time of the day, due to the influence of new particle formation events. When validated at the second station, performance indicators decreased (R-2 = 0.633; RMSE = 1.19 mu g/m(3)) due to the lack of N data and PM2.5 and the smaller size of the dataset (2 months). New particle formation events critically impacted model performance, suggesting that its application would be optimal in environments where traffic is the main source of ultrafine particles. Due to its flexibility, it is concluded that the model can act as a BC proxy, even based on EU-regulatory air quality parameters only, to complement experimental measurements for exposure assessment in urban areas.Peer reviewe