Inviolable energy conditions from entanglement inequalities

Via the AdS/CFT correspondence, fundamental constraints on the entanglement structure of quantum systems translate to constraints on spacetime geometries that must be satisfied in any consistent theory of quantum gravity. In this paper, we investigate such constraints arising from strong subadditivity and from the positivity and monotonicity of relative entropy in examples with highly-symmetric spacetimes. Our results may be interpreted as a set of energy conditions restricting the possible form of the stress-energy tensor in consistent theories of Einstein gravity coupled to matter.Comment: 25 pages, 3 figures, v2: refs added, expanded discussion of strong subadditivity constraints in sections 2.1 and 4.

LIFE CYCLE ASSESSMENT OF A HEMP CONCRETE WALL: IMPACT OF THICKNESS AND COATING.

International audienceIn a context of sustainable development and energy sparing, a life cycle assessment (LCA) may be useful to make good choices. Thus, this study concerns the LCA of an environmentally friendly material used for building construction, hemp concrete. The functional unit is first defined per square such that the wall may provide the function of bearing wall meter and its thermal performance is described by a thermal resistance of 2.78 m².K/W. The results then showed that the production phase of raw materials is mainly responsible for the environmental impact of the wall, mostly due to the binder production. It was also shown that, compared to traditional construction materials, hemp concrete has a low impact on environment. Moreover, hemp concrete contributes to reduce climate change as photosynthesis-mediated carbon sequestration and carbonation serve to reduce atmospheric carbon dioxide. A sensitivity analysis is performed on three criteria: wall thickness, renewal of coatings and compounds of the indoor coating. Our results show that environmental indicators evolve with wall thickness, except for the climate change indicator. It improves with thickness due to carbon sequestration and carbonation. Moreover the increase in the wall's thermal resistance with wall thickness is not taken into account in such an LCA performed at the material level. The renewal of coating slightly impacts the environmental indicator for small numbers of renewals but it leads to negative effects if they are too numerous. It appears that hemp-lime coating has a greater impact than sand-lime coating as it embeds more binder

Familiarity Detection with the Component Process Model

International audienceWe propose a computational model for the Component Process Model (CPM) of Scherer, the most recent and the most complete model of emotion in psychology. This one proposes to appraise a stimulus through a sequence of sixteen appraisal variables dealing with a large number of its characteristics. As CPM is very abstract and high level, it is not really used in affective computing and no formal models exist for its appraisal variables. Based on the CPM, in this paper we propose a mathematical function for one appraisal variable detecting the familiarity of a perceived event according to the state of the cognitive component of an agent (goals, needs, semantic memory, and episodic memory)

On the physics behind coastal morphodynamic patterns

Peer ReviewedPostprint (published version

Nearshore sand bars

This research has been funded by the Spanish government through the research projects CTM2012-35398 (cofunded by FEDER, U.E.) and CTM2015-66225-C2-1-P (MINECO/FEDER).This review summarizes the morphological characteristics and dynamics of nearshore sand bars observed in the surf zone of sandy beaches worldwide, with length scales ranging from tens to hundreds of meters and time scales ranging from hours to weeks. They include shore-parallel bars (straight and crescentic) and transverse bars of different types. Furthermore, the present knowledge on the physical processes behind their formation and development is discussed.Peer ReviewedPostprint (published version

Intertidal finger bars at El Puntal, Bay of Santander, Spain: observation and forcing analysis

A system of 15 small-scale finger bars has been observed, by using video imagery, between 23 June 2008 and 2 June 2010. The bar system is located in the intertidal zone of the swell-protected beaches of El Puntal Spit, in the Bay of Santander (northern coast of Spain). The bars appear on a planar beach (slope = 0.015) with fine, uniform sand (D50 = 0.27 mm) and extend 600 m alongshore. The cross-shore span of the bars is determined by the tidal horizontal excursion (between 70 and 130 m). They have an oblique orientation with respect to the low-tide shoreline; specifically, they are down-current-oriented with respect to the dominant sand transport computed (mean angle of 26° from the shore normal). Their mean wavelength is 26 m and their amplitude varies between 10 and 20 cm. The full system slowly migrates to the east (sand transport direction) with a mean speed of 0.06 m day-1, a maximum speed in winter (up to 0.15 m day-1) and a minimum speed in summer. An episode of merging has been identified as bars with larger wavelength seem to migrate more slowly than shorter bars. The wind blows predominantly from the west, generating waves that transport sediment across the bars during high-tide periods. This is the main candidate to explain the eastward migration of the system. In particular, the wind can generate waves of up to 20 cm (root-mean-squared wave height) over a fetch that can reach 4.5 km at high tide. The astronomical tide seems to be important in the bar dynamics, as the tidal level changes the fetch and also determines the time of exposure of the bars to the surf-zone waves and currents. Furthermore, the river discharge could act as input of suspended sediment in the bar system and play a role in the bar dynamics

SMALL AND MEDIUM PORTS' ACTIVITIES MODELLING: INTRODUCTION TO THE PIXEL APPROACH

[EN] Port activities undeniably have an impact on their environment, the city and citizens living nearby. To have a better understanding of these impacts, the ports of the future will require tools allowing suitable modelling, simulation and data analysis. This challenge is also tied to another current reality: the heterogeneous data coming from different stakeholders converging into ports are not optimally exploited due to lack of interoperability. Thus, the forthcoming research and development initiatives must address these demands from a holistic point of view. PIXEL (H2020-funded project) aims at creating the first smart, flexible and scalable solution reducing the environmental impact while enabling optimization of operations in port ecosystems. PIXEL brings the most innovative IoT and ICT technology to ports and demonstrate their capacity to take advantage of modern approaches. Using an interoperable open IoT platform, data is acquired and integrated into an information hub comprised of small, low-level sensors up to virtual sensors able to extract relevant data from high level services. Finally, this hub integrates smart models to analyse port processes for prediction and optimization purposes: (i) a model of consumption and energy production of the port with the aim of moving towards green energy production; (ii) a model of congestion of multi-modal transport networks to reduce the impact of port traffic on the network; and (iii) models of environmental pollution of the port to reduce the environmental impacts of the port on the city and its citizens. The main issue tackled by PIXEL is to provide interoperability between these models and allow real integration and communication in the context of an environmental management model. Besides that, PIXEL devotes to decouple port¿s size and its ability to deploy environmental impact mitigation specifying an innovative methodology and an integrated metric for the assessment of the overall environmental impact of ports.The PIXEL project, the results of which are presented in this paper, is being funded from the European Union s Horizon 2020 research and innovation programme under grant agreement no. 769355 Port IoT for Environmental Leverage (PIXEL)Simon, E.; Garnier, C.; Lacalle, I.; Costa, JP.; Palau Salvador, CE. (2019). SMALL AND MEDIUM PORTS' ACTIVITIES MODELLING: INTRODUCTION TO THE PIXEL APPROACH. WIT Transactions on the Built Environment (Online). 187:149-163. https://doi.org/10.2495/MT190141S14916318

Prospectives

Tiré de: Prospectives, vol. 23, no 1, février 1987Titre de l'écran-titre (visionné le 24 janv. 2013

The View from the Top: CALIOP Ice Water Content in the Uppermost Layer of Tropical Cyclones

NASA's CALIPSO satellite carries both the Cloud and Aerosol Lidar with Orthogonal Polarization (CALIOP) and the Imaging Infrared Radiometer (IIR). The lidar is ideally suited to viewing the very top of tropical cyclones, and the IIR provides critical optical and microphysical information. The lidar and the IIR data work together to understand storm clouds since they are perfectly co-located, and big tropical cyclones provide an excellent complex target for comparing the observations. There is a lot of information from these case studies for understanding both the observations and the tropical cyclones, and we are just beginning to scratch the surface of what can be learned. Many tropical cyclone cloud particle measurements are focused on the middle and lower regions of storms, but characterization of cyclone interaction with the lowermost stratosphere at the upper storm boundary may be important for determining the total momentum and moisture transport budget, and perhaps for predicting storm intensity as well. A surprising amount of cloud ice is to be found at the very top of these big storms

Influencia de las bajas frecuencias en el RUN-UP en playas: mediciones en la Playa de Somo, Santander.

Los autores agradecen el suporte del Ministerio de Economía y Competitividad a través de la financiación del proyecto MUSCLE-Beach (BIA2014-59643-R)