On the contribution of ULXs to stellar feedback: an intermediate mass black hole candidate and the population of ULXs in the low-metallicity starburst galaxy ESO 338-4

X-ray radiation from accreting compact objects is an important part of stellar feedback. The metal-poor galaxy ESO 338-4 has experienced vigorous starburst during the last 40 Myr and contains some of the most massive super star clusters in the nearby Universe. Given its starburst age and its star-formation rate, ESO 338-4 is one of the most efficient nearby manufactures of neutron stars and black holes, hence providing an excellent laboratory for feedback studies. We compared X-ray images and spectra obtained by XMM-Newton and Chandra telescopes with integral field spectroscopic VLT MUSE observations in the optical to constrain the nature of strong X-ray emitters. X-ray observations uncover three ultraluminous X-ray sources (ULXs) in ESO 338-4. The brightest among them, ESO 338~X-1, has X-ray luminosity in excess of 10^{40} erg/s. We speculate that ESO 338-4 is powered by accretion on an intermediate-mass (~300Msun) black hole. We show that X-ray radiation from ULXs and hot superbubbles strongly contributes to HeII ionization and general stellar feedback in this template starburst galaxy.Comment: A&A, in pres

Frozen dynamics and synchronization through a secondary symmetry-breaking bifurcation

We show evidence of the frozen dynamics (Kibble-Zurek mechanism) at the transition one-dimensional (1D) front of an extended 1D array of convective oscillators that undergo a secondary subcritical bifurcation. Results correspond to a global synchronization process from nonlocal coupling between the oscillating units. The quenched dynamics exhibits defect trapping at the synchronization front according to the Kibble-Zurek mechanism, predicted for condensed matter systems. A stronger subcriticality prevents the fronts from freezing defects during the quenched transitions. A synchronization model of supercritical oscillating units is proposed to explain differentiation mechanisms in morphogenesis above a critical crossing rate when the frequency of the individual oscillators becomes coherent. The phases of such oscillators are spatially coupled through a Kuramoto-Battogtokh term that leads to the experimentally observed subcriticality. As a consequence, we show that the Kibble-Zurek mechanism overcomes non-locality of a geometrical network above a critical crossing rate

Sistema de gestión de energía para microrredes basado en control predictivo

En este artículo se presenta un sistema de gestión de energía para microrredes a partir de un control Predictivo basado en Modelos (MPC), el cual tiene como tarea la optimización de las operaciones de una microrred, al tiempo que cumple una serie de restricciones de funcionamiento. Para ello, el problema ha sido formulado empleando Programación Lineal Entera-Mixta (MILP), la cual ha sido resuelta de manera eficiente. Se han estudiado diferentes escenarios, comparando el MPC con una estrategia fija y se han calculado costes de funcionamiento e inversión, mostrando finalmente los resultados.Los autores quieren agradecer a la Universitat Jaume I y a la Generalitat Valenciana el apoyo recibido y materializado en los proyectos P11B2013-34 y GV/2014/117 respectivamente

Exploring the Kibble-Zurek mechanism in a secondary bifurcation

We present new experimental results on the quenching dynamics of an extended thermo-convective system (a network array of approximately 100 convective oscillators) going through a secondary subcritical bifurcation. We characterize a dynamical phase transition through the nature of the domain walls (1D-fronts) that connect the basic multicellular pattern with the new oscillating one. Two different mechanisms of the relaxing dynamics at the threshold are characterized depending on the crossing rate $\mu=\left.\frac{d\varepsilon}{dt}\right|_{\varepsilon=0}$ of the quenched transition. From the analysis of fronts, we show that these mechanisms follow different correlation length scales $\xi \sim \mu^{-\sigma}$. Below a critical value $\mu_c$, a slow response dynamics yields a spatiotemporal coherent front with weak coupling between oscillators. Above $\mu_c$, for rapid quenches, defects are trapped at the front with a strong coupling between oscillators, similarly to the Kibble-Zurek mechanism in quenched phase transitions. These defects, pinned to the fronts, yield a strong decay of the correlation length

Control de la tensión del bus de continua de un filtro activo mediante un convertidor DC-DC

En este artículo se presentan los resultados experimentales obtenidos mediante un sistema compensador generador trabajando de forma aislada de la red eléctrica. Para analizar el funcionamiento del sistema se ha desarrollado un prototipo de un convertidor DC-DC bidireccional el cual permite adaptar el valor de la tensión de las baterías conectadas a su entrada con la tensión del bus de continua a la entrada del filtro activo. Para el control del convertidor DC-DC se ha utilizado un control por realimentación del estado diseñado mediante algoritmos genéticos, y en el caso del filtro activo se ha utilizado un control proporcional con prealimentación. Los resultados experimentales obtenidos muestran el correcto funcionamiento del sistema tanto en estado estacionario, como en régimen transitorio.Los autores quieren agradecer a la Universitat Jaume I y a la Generalitat Valenciana el apoyo recibido y materializado en los proyectos P11B2013-34 y GV/2014/117 respectivamente

Neural response to the observable self in social anxiety disorder

Background: Distorted images of the observable self are considered crucial in the development and maintenance of social anxiety. We generated an experimental situation in which participants viewed themselves from an observer's perspective when exposed to scrutiny and evaluation by others. Method: Twenty patients with social anxiety disorder (SAD) and 20 control subjects were assessed using functional magnetic resonance imaging (fMRI) during the public exposure of pre-recorded videos in which they were each shown performing a verbal task. The examiners acted as the audience in the experiment and rated performance. Whole-brain functional maps were computed using Statistical Parametric Mapping. Results: Robust activation was observed in regions related to self-face recognition, emotional response and general arousal in both study groups. Patients showed significantly greater activation only in the primary visual cortex. By contrast, they showed significant deactivation or smaller activation in dorsal frontoparietal and anterior cingulate cortices relevant to the cognitive control of negative emotion. Task-related anxiety ratings revealed a pattern of negative correlation with activation in this frontoparietal/cingulate network. Importantly, the relationship between social anxiety scores and neural response showed an inverted-U function with positive correlations in the lower score range and negative correlations in the higher range. Conclusions: Our findings suggest that exposure to scrutiny and evaluation in SAD may be associated with changes in cortical systems mediating the cognitive components of anxiety. Disorder severity seems to be relevant in shaping the neural response pattern, which is distinctively characterized by a reduced cortical response in the most severe cases

Task-induced deactivation from rest extends beyond the default mode brain network

Activity decreases, or deactivations, of midline and parietal cortical brain regions are routinely observed in human functional neuroimaging studies that compare periods of task-based cognitive performance with passive states, such as rest. It is now widely held that such task-induced deactivations index a highly organized"default-mode network" (DMN): a large-scale brain system whose discovery has had broad implications in the study of human brain function and behavior. In this work, we show that common task-induced deactivations from rest also occur outside of the DMN as a function of increased task demand. Fifty healthy adult subjects performed two distinct functional magnetic resonance imaging tasks that were designed to reliably map deactivations from a resting baseline. As primary findings, increases in task demand consistently modulated the regional anatomy of DMN deactivation. At high levels of task demand, robust deactivation was observed in non-DMN regions, most notably, the posterior insular cortex. Deactivation of this region was directly implicated in a performance-based analysis of experienced task difficulty. Together, these findings suggest that task-induced deactivations from rest are not limited to the DMN and extend to brain regions typically associated with integrative sensory and interoceptive processes

Hypersonic Bose–Einstein condensates in accelerator rings

© 2019, The Author(s), under exclusive licence to Springer Nature Limited. Some of the most sensitive and precise measurements—for example, of inertia1, gravity2 and rotation3—are based on matter-wave interferometry with free-falling atomic clouds. To achieve very high sensitivities, the interrogation time has to be very long, and consequently the experimental apparatus needs to be very tall (in some cases reaching ten or even one hundred metres) or the experiments must be performed in microgravity in space4–7. Cancelling gravitational acceleration (for example, in atomtronic circuits8,9 and matter-wave guides10) is expected to result in compact devices with extended interrogation times and therefore increased sensitivity. Here we demonstrate smooth and controllable matter-wave guides by transporting Bose–Einstein condensates (BECs) over macroscopic distances. We use a neutral-atom accelerator ring to bring BECs to very high speeds (16 times their sound velocity) and transport them in a magnetic matter-wave guide for 15 centimetres while fully preserving their internal coherence. The resulting high angular momentum of more than 40,000ħ per atom (where ħ is the reduced Planck constant) gives access to the higher Landau levels of quantum Hall states, and the hypersonic velocitiesachieved, combined with our ability to control potentials with picokelvin precision, will facilitate the study of superfluidity and give rise to tunnelling and a large range oftransport regimes of ultracold atoms11–13. Coherent matter-wave guides are expected to enable interaction times of several seconds in highly compact devices and lead to portable guided-atom interferometers for applications such as inertial navigation and gravity mapping

The Fourteenth Data Release of the Sloan Digital Sky Survey: First Spectroscopic Data from the extended Baryon Oscillation Spectroscopic Survey and from the second phase of the Apache Point Observatory Galactic Evolution Experiment

The fourth generation of the Sloan Digital Sky Survey (SDSS-IV) has been in operation since July 2014. This paper describes the second data release from this phase, and the fourteenth from SDSS overall (making this, Data Release Fourteen or DR14). This release makes public data taken by SDSS-IV in its first two years of operation (July 2014-2016). Like all previous SDSS releases, DR14 is cumulative, including the most recent reductions and calibrations of all data taken by SDSS since the first phase began operations in 2000. New in DR14 is the first public release of data from the extended Baryon Oscillation Spectroscopic Survey (eBOSS); the first data from the second phase of the Apache Point Observatory (APO) Galactic Evolution Experiment (APOGEE-2), including stellar parameter estimates from an innovative data driven machine learning algorithm known as "The Cannon"; and almost twice as many data cubes from the Mapping Nearby Galaxies at APO (MaNGA) survey as were in the previous release (N = 2812 in total). This paper describes the location and format of the publicly available data from SDSS-IV surveys. We provide references to the important technical papers describing how these data have been taken (both targeting and observation details) and processed for scientific use. The SDSS website (www.sdss.org) has been updated for this release, and provides links to data downloads, as well as tutorials and examples of data use. SDSS-IV is planning to continue to collect astronomical data until 2020, and will be followed by SDSS-V.Comment: SDSS-IV collaboration alphabetical author data release paper. DR14 happened on 31st July 2017. 19 pages, 5 figures. Accepted by ApJS on 28th Nov 2017 (this is the "post-print" and "post-proofs" version; minor corrections only from v1, and most of errors found in proofs corrected