Holographic Relaxation of Finite Size Isolated Quantum Systems

We study holographically the out of equilibrium dynamics of a finite size closed quantum system in 2+1 dimensions, modelled by the collapse of a shell of a massless scalar field in AdS4. In global coordinates there exists a variety of evolutions towards final black hole formation which we relate with different patterns of relaxation in the dual field theory. For large scalar initial data rapid thermalization is achieved as a priori expected. Interesting phenomena appear for small enough amplitudes. Such shells do not generate a black hole by direct collapse, but quite generically an apparent horizon emerges after enough bounces off the AdS boundary. We relate this bulk evolution with relaxation processes at strong coupling which delay in reaching an ergodic stage. Besides the dynamics of bulk fields, we monitor the entanglement entropy, finding that it oscillates quasi-periodically before final equilibration. The radial position of the traveling shell is brought into correspondence with the evolution of the entanglement pattern in the dual field theory. The entanglement entropy is not only able to portrait the streaming of entangled excitations, but it is also a useful probe of interaction effects.Comment: 37 pages, 27 figure

On the Use of a Parallel Object-Oriented Code for Solving the Heat Transfer in Hermetic Reciprocating Compressors

The heat transport phenomenon in a hermetic reciprocating compressor is addressed in this work. This is far from straightforward. It involves several transient physical phenomena interacting to each other. The heat is exchanged between the refrigerant fluid and the solid parts of the compressor (suction muffler, cylinder head, crankcase, etc.). At the same time, the solid parts exchange heat to each other by means of conduction and radiation. Moreover, the phenomenon happens in non-symmetrical complex geometries and the solid parts are made of different materials. This is interesting from both the software engineering and the compressor design viewpoint. A parallel object-oriented software platform for the resolution of multiphysics problems is employed. This platform allows the use of partitioned strategies so that the compressor heat transport problem -a global problem- can be divided into several smaller parts -local problems-. This makes possible the use of multilevel modeling strategies for thermal systems analysis. Furthermore, in order to couple the several sub-problems in an integrated simulation, the platform provides data transfer tools -for matching and non-matching meshes- to exchange sub-domain state information. In particular, the work provides detailed information on the heat distribution and the temperature of the components of a test compressor. By means of comparative studies the thermal properties of some of its components are analyzed. This highlights the importance of choosing proper materials. For example, different suction muffler materials are tested to investigate their influence on the volumetric efficiency. Since the whole compressor is simulated, the consequences of altering specific component properties are also appreciated on the other components. In sum, the work presents illustrative numerical results of the three-dimensional heat transfer in a compressor that show the potential use of computer simulation to support design of components to attain feasibility and energy efficiency

Inverse cascades sustained by the transfer rate of angular momentum in a 3D turbulent flow

The existence of energy cascades as signatures of conserved magnitudes is one of the universal characteristics of turbulent flows. In homogeneous 3D turbulence, the energy conservation produces a direct cascade from large to small scales, although in 2D, it produces an inverse cascade pointing towards small wave numbers. In this Letter, we present the first evidence of an inverse cascade in a fully developed 3D experimental turbulent flow where the conserved magnitude is the angular momentum. Two counterrotating flows collide in a central region where very large fluctuations are produced, generating a turbulent drag that transfers the external torque between different fluid layers

Gestión del tiempo y estrés académico en ingresantes de salud de una universidad pública – 2023.

El objetivo del estudio fue determinar la relación entre la gestión del tiempo y el estrés académico en los ingresantes de la Universidad Nacional Toribio Rodríguez de Mendoza de Amazonas en el año 2023. La investigación se basó en un enfoque cuantitativo y adoptó un diseño básico no experimental de alcance correlacional, utilizando un muestreo no probabilístico por conveniencia. La muestra estuvo conformada por un total de 106 estudiantes de la Facultad de Ciencias de la Salud, abarcando las escuelas profesionales de Enfermería, Estomatología y Psicología, además a la Facultad de Medicina, siendo el 51.89% de género masculino y el 48.11% de género femenino. Para recopilar la información, se utilizaron dos cuestionarios, el Inventario de Estrés Académico que presenta una confiabilidad de 0.87 y el Cuestionario de Gestión del Tiempo en Universitarios que presenta una confiabilidad de 0.71. Se realizó el análisis estadístico a través de Rho de Spearman y estadística descriptiva. Los resultados revelaron que el 92.45% de los estudiantes del primer ciclo de la Facultad de Ciencias de la Salud experimentan un nivel moderado de estrés, mientras que el 90.57% tiene una gestión del tiempo regular. Asimismo, se encontró una correlación positiva moderada (0.277) entre la gestión del tiempo y el estrés académico en los ingresantes de la UNTRM-2023. Se llegó a la conclusión que, la mayoría de los estudiantes ingresantes muestran niveles moderados de estrés académico

HERRAMIENTAS PARA LA PARTICIPACIÓN EN LA SOSTENIBILIDAD EIA EN LA INGENIERÍA CIVIL

TOOLS FOR SOCIAL PARTICIPATION IN THE SUSTAINABILITY OF ENVIRONMENTAL IMPACT STUDIES IN CIVIL ENGINEERIN

Collapse and Revival in Holographic Quenches

We study holographic models related to global quantum quenches in finite size systems. The holographic set up describes naturally a CFT, which we consider on a circle and a sphere. The enhanced symmetry of the conformal group on the circle motivates us to compare the evolution in both cases. Depending on the initial conditions, the dual geometry exhibits oscillations that we holographically interpret as revivals of the initial field theory state. On the sphere, this only happens when the energy density created by the quench is small compared to the system size. However on the circle considerably larger energy densities are compatible with revivals. Two different timescales emerge in this latter case. A collapse time, when the system appears to have dephased, and the revival time, when after rephasing the initial state is partially recovered. The ratio of these two times depends upon the initial conditions in a similar way to what is observed in some experimental setups exhibiting collapse and revivals

The 2017 PREDICT Key Facts Report. An Analysis of ICT R&D in the EU and Beyond

The 2017 PREDICT Key Facts Report provides a detailed analysis of the state of ICT R&D activities in the European Union. This is the tenth edition of a series that is published annually. Like the previous editions, an online version is available at: https://ec.europa.eu/jrc/en/predict. The PREDICT dataset 2017 is based on the latest data available from official sources (such as the Eurostat and OECD, National Accounts and R&D statistics). It also includes the novelty of backwards reconstruction of the series from 1995, which allows it to cover the period from 1995 to 2014. Therefore, it provides a long-term analysis of the EU ICT sector and its R&D, covering a whole cycle since the initial expansion years, the double recession that began in early 2008, and the most recent evolution up to 2014.JRC.B.6-Digital Econom

Assessment of the Impact of Long Integration Time in Geosynchronous SAR Imagery of Agricultural Fields by Means of GB-SAR Data

Geosynchronous Synthetic Aperture Radar (GeoSAR) missions offer the advantage of near-continuous monitoring of specific regions on Earth, making them essential for applications that require continuous information. However, wind induced motion along the inherent long integration time can result in image defocusing, with potential degradation of retrieved information. This paper aims to investigate the impact of GEOSAR long integration time in Synthetic Aperture Radar (SAR) imaging and derived products (time series of backscatter and coherence) required to extract agriculture relevant soil or crop parameters of interest. The study is based on the extensive HydroSoil data acquisition campaign carried out over barley and corn crops, funded by the European Space Agency (ESA). The collected raw data are used to synthesize equivalent apertures with integration times of up to 4 hours, similar to those acquired with a GeoSAR. These Ultra Slow apertures facilitate the assessment of the impact of agricultural scene decorrelation on the generation of images with extended integration times.This work was funded by the European Space Agency (ESA Contract No. 4000132509/20/NL/FF/ab with UPC), supported by the Spanish MCINN funds Unidad de Excelencia Maria de Maeztu MDM-2016-0600 and under projects PID2020-117303GB-C21/AEI/10.13039/501100011033 and PID2020-117303GB-C22/AEI/10.13039/501100011033

Limits on Relief through Constrained Exchange on Random Graphs

Agents are represented by nodes on a random graph (e.g., small world or truncated power law). Each agent is endowed with a zero-mean random value that may be either positive or negative. All agents attempt to find relief, i.e., to reduce the magnitude of that initial value, to zero if possible, through exchanges. The exchange occurs only between agents that are linked, a constraint that turns out to dominate the results. The exchange process continues until a Pareto equilibrium is achieved. Only 40%-90% of the agents achieved relief on small world graphs with mean degree between 2 and 40. Even fewer agents achieved relief on scale-free like graphs with a truncated power law degree distribution. The rate at which relief grew with increasing degree was slow, only at most logarithmic for all of the graphs considered; viewed in reverse, relief is resilient to the removal of links.Comment: 8 pages, 2 figures, 22 references Changes include name change for Lory A. Ellebracht (formerly Cooperstock, e-mail address stays the same), elimination of contractions and additional references. We also note that our results are less surprising in view of other work now cite