Entanglement and correlations in the continuous multi-scale entanglement renormalization ansatz

We investigate the entanglement structure of the continuous multi-scale entanglement renormalization ansatz (cMERA) [Haegeman et al., Phys. Rev. Lett., 110, 100402 (2013)] for ground states of quantum field theories (QFTs). The cMERA, proposed as an extension to QFTs of the lattice MERA, is defined directly in the continuum but is nevertheless naturally equipped with a short-distance scale $1/\Lambda$ that acts as a UV regulator for quantum fluctuations. We consider the simplified setting of Gaussian cMERA for free QFTs, where explicit calculations can be performed. For relativistic free massless bosonic and fermionic QFTs in both 1+1 and 2+1 spacetime dimensions, we show that the cMERA state indeed displays no UV divergences in two-point correlation functions or entanglement entropy, in sharp contrast with the exact ground states.Comment: 28 pages, 20 figures, 4 appendices. Improved with referee's comment

Uso de suelo y biomateriales

Ponencia presentada en el XI Congreso Internacional de Ingeniería de Proyectos celebrado en Lugo en el año 2007When designing a product made of biodegradable materials, all of the impacts associated with the product along its life cycle should be taken into account. The replacement of conventional materials by biopolymers entails modifications of environmental impacts which are not always evident or easy to quantify. Existing Life Cycle Assessments (LCA) studies of biopolymers have often neglected the land use impact category. Given that the organic fraction of biodegradable products often comes from agricultural waste, this category arises as an essential environmental issue due to the impacts of crops. Should biodegradable materials have great market success, it is possible that additional land would have to be transformed into crop fields, therefore causing environmental impacts from land use. There are several methodologies available to assess this impact. A comparison of them is carried out in this study, using several data source. In order to illustrate the disparity among the existing methods for assessing the impact on land use, the impact caused by the substitution of a certain type of land for a one-hectare potato crop field was assessed. Two areas in Spain possessing different soil characteristics were chosen. These were the Mediterranean forests of the Iberian mountain group and the pastures of the north-western Cantabrian region. Results come to show that no reliable methodologies have yet been developed to assess land use, even though this is a crucial impact category given its long-term implications on soil qualityA la hora de diseñar un producto realizado con materiales biodegradables, se deben tener en cuenta todos los impactos asociados a lo largo de su ciclo de vida. El reemplazo de materiales convencionales por biomateriales conlleva impactos medioambientales que no son siempre evidentes ni fáciles de cuantificar. La mayoría de los Análisis de Ciclo de Vida (ACV) existentes sobre biopolímeros no se han ocupado de la categoría de impacto de uso del suelo. Dado que la fracción orgánica de los productos biodegradables proviene normalmente de residuos agrícolas, esta categoría de impacto surge como una cuestión medioambiental primordial debido a los impactos que producen los cultivos. En el caso de que los biopolímeros tuvieran un gran éxito en el mercado, probablemente surgiría la necesidad de plantar nuevos campos de cultivo para cubrir la demanda, causando así nuevos impactos medioambientales derivados del uso del suelo. Hay varias metodologías disponibles para evaluar dichos impactos. En este estudio se hace una comparación de las mismas, empleando distintas fuentes de datos para su aplicación. Para ilustrar la disparidad existente entre los métodos actuales, se evalúa el impacto causado por una hectárea de cultivo de patatas en dos zonas de España con diferentes características y tipo de suelo: los bosques mediterráneos del Sistema Ibérico y los pastos de la región cantábrica. Los resultados vienen a mostrar que no se han desarrollado aún metodologías fiables para evaluar esta categoría de impacto, a pesar de su importancia dadas sus implicaciones a largo plazo en la calidad del suelo

Impact of drought on Eucalyptus wood chemistry by near infra red hyperspectral imaging

The aim is to study tree development submitted to different water and mineral constraints. The objective is to correlate spatial distribution of wood chemistry with wood density secondary growth. We sampled wood discs from 54 trees in rainfall exclusion design with Eucalyptus grandis at Esalq-USP. ltatinga Station.brazil. We felled the 5 years old trees growing under different water availability. For each disk. we acquired an image with a near infrared (nir) hyperspectral camera (hs1, specim. pixel size 625 x 625µml. The challenge here was to transfer our previous nir calibrations for total extractives built with a benchtop spectrometer (vector. bruker) to a hsi camera by using standard sample set measured ,>n the two devices. An efficient model were built for the his camera with a prediction error of 10.3% compared to the prediction error of 11.60% for our previous calibration with benchtop spectrometer. Then, based on spectra from his image. we predicted extractive contents and built images. These allow us to compare their spatial distributions according to the growth conditions. In the absence or absence or fertilization, trees with higher water stress showed a higher heterogeneous distribution. from pith to bark, for the total extractive contents and a higher average mean value. In perspective. these data will allow us to study and reline the knowledge on cambium activity according to climatic variations by crossing variability of the chemical properties, x-ray micro-density and anatomy of wood, and diameter growth rate measured by electronic dendrometers

A fair method for the calculation of the external costs of road traffic noise according to the Eurovignette Directive

This paper presents calculations of the costs of road traffic noise in Europe that include the development of improved noise weighting factors according to vehicle class, speed and time of the day. The Eurovignette Directive allows EU Member States to levy infrastructure charges to compensate for the external costs of noise caused by heavy goods vehicles. Here we outline a method to calculate such costs in accordance to the Eurovignette Directive, which requires using weighting factors both for vehicle classes and times of the day. The Directive does not provide specific values or guidelines for calculating these factors. Moreover, while the Directive only focuses on the charging of heavy goods vehicles for day and night, we extend the calculations to other vehicle classes and time periods

Análisis del ciclo de vida del reciclado del polietileno de alta densidad

Thermoplastics make up roughly 80% of the plastics produced today. There are hundreds of types of them and new variations are being developed. But not all thermoplastics are recyclable in the same proportion. The most commonly recycled thermoplastics are polyethylene (PE), polypropylene (PP), polystyrene (PS) and polyvinyl chloride (PVC). In this study, real data from the industry is used in the analysis of the environmental impact of plastics recycling by means of the application of the Life Cycle Assessment (LCA) methodology to the products and processes involved in mechanical plastic recycling of black high density polyethylene (HDPE) for extrusion or blow moulding coming from industrial scrap. The results obtained were compared with assessments made by other authors and with the impact associated with the manufacturing of virgin thermoplastic according to databases. The interpretation of these comparisons leads us to conclude that the recycling process has been optimised over the past years, thus reducing its environmental impact. Furthermore, the clear advantages from the eco-efficiency viewpoint of plastic recycling against direct manufacturing from petroleum are highlightedLos termoplásticos constituyen aproximadamente el 80% de los plásticos producidos hoy en día. Actualmente existen muchos tipos de termoplásticos. No obstante, se siguen desarrollando nuevos tipos. Sin embargo, no todos los termoplásticos se reciclan en igual proporción. Los que más comúnmente se reciclan son el polietileno (PE), el polipropileno (PP), el poliestireno (PS) y el cloruro de polivinilo (PVC). En este estudio, se han utilizado datos reales de una industria dedicada al reciclaje de plásticos para realizar el análisis del impacto ambiental a través de la aplicación de la metodología del Análisis del Ciclo de Vida (ACV) de los productos y procesos que intervienen en el reciclaje mecánico de polietileno de alta densidad (PEAD) negro, para la extrusión o soplado procedentes de residuos industriales. Los resultados obtenidos se han comparado con otros análisis realizados por otros autores y con impacto medioambiental asociado a la fabricación de termoplástico virgen procedentes de bases de datos. Al interpretar estas comparaciones, se puede concluir que el proceso de reciclaje se ha optimizado en los últimos años, lo que reduce su impacto ambiental, además de destacar las claras ventajas desde el punto de vista de la eficiencia ecológica de reciclaje de plástico frente a la fabricación directa de petróle

El marco DPSIR en los sectores de transporte y agricultura: necesidad del desarrollo de indicadores de impacto en las categorías de ruido y uso de suelo

Ponencia presentada en el XIII Congreso Internacional de Ingeniería de Proyectos celebrado en Badajoz , 8-10 de julio de 2009The use of statistical values or environmental measurement results does not suffice to reflect the environmental impact of the sectors of transport and agriculture. Despite its large incidence upon sustainability, decision-making in environmental assessment contexts has usually been based upon the development of simple pressure and state indicators. In this study, an analysis of environmental indicators developed by several international organisms within the DPSIR (Driving-Force, Pressure, State, Impact, Response) framework was performed. The results seem to confirm that impact indicators do not reflect the real impacts, either upon human beings, other living creatures or natural resources. In the case of transport noise, impact indicators typically reflect exposure and annoyance levels. On the other hand, land use indicators -for both transport and agriculture- are based upon surface occupation data. Thus, further development of indicators is needed in both sectors to more accurately reflect environmental impacts. The application of the Life Cycle Assessment methodology seems adequate in this case, since it allows for the determination of overall impacts attributable to a product or process.La utilización única de valores estadísticos o procedentes de mediciones ambientales no es suficiente para reflejar el impacto medioambiental de los sectores del transporte y de la agricultura. A pesar de su incidencia sobre la sostenibilidad, la toma de decisiones para evaluar el impacto medioambiental se ha basado normalmente en el desarrollo de indicadores simples de presión y estado. En este estudio se ha realizado un análisis de indicadores medioambientales dentro del marco DPSIR (del inglés, Driving-Force, Pressure, State, Impact, Response) desarrollados por diversas organizaciones mundiales. Como resultado se puede comprobar que los indicadores de impacto no reflejan un impacto real, ya sea sobre las consecuencias en el propio ser humano, en otros seres vivos o en los recursos naturales. En el caso del ruido del transporte, estos reflejan generalmente los niveles de exposición y molestia de las personas, mientras que en el caso de la categoría de uso del suelo en ambos sectores, únicamente se presentan datos de ocupación superficial. Por lo tanto, es necesario el desarrollo de indicadores de impacto de las citadas categorías que reflejen el estado medioambiental real. La aplicación de la metodología del Análisis del Ciclo de Vida es muy conveniente para este desarrollo ya que permite determinar el impacto asociado de forma global a un producto o proceso

Prediction of Eucalyptus grandis chemical compounds in a climate change context using hyperspectral imaging

The study of wood chemistry to explain the response of trees to climate variation is efficient for retrospective analysis of changes induced in wood during the process of adaptation to seasonal variations. Hyperspectral imaging (HSI) in near infrared could be useful for prediction of several wood chemical components. The objective is understand how water constraints influence wood formation. Wood disks of E. grandis clone from six treatments (100% and 65% of rainfall crossed with potassium and sodium fertilizations) were sampled. HSI were obtained on transversal section of the disks using a line scan hyperspectral camera from 1000-2500 nm with a pixel size of 625 x 625 µm. For calibration, were selected 60 wood solid samples from an Eucalyptus collection, which were measured the total extractive values. HSI or these samples were acquired from transversal section with the same camera. We regressed the mean spectra for each sample with extractives values by Partial Least Square Regression. Due to the model, the total extractives for each pixel to produce an image for the wooden disks were predicted. Based on them, the total extractive distribution according to growth conditions were compared. revealing that trees under stress conditions show a higher heterogeneous chemical profile from the pith to bark. Eucalyptus demonstrates sensitive precipitation variations. with rapid growth and considerable increase in DBH during rainy seasons and the reverse in drought. Consequently, is possible to discriminate different patterns of chemical compound distribution according to the growth conditions

Ocupación y transformación del suelo de las carreteras españolas

Ponencia presentada en el XII Congreso Internacional de Ingeniería de Proyectos celebrado en Zaragoza en el año 2008The term ‘land use’ is traditionally used to denote a classification of human activities which occupy land area. In the field of Life Cycle Assessment (LCA), the terms ‘land use’ or ‘land use impact’ have been used to designate the environmental impacts related to physical occupation and transformation of geographic areas. Our study focuses on the calculation of land surface occupation attributed to Spanish roads, stressing the discrepancy of results determined by the choice of data source. Occupation values are subsequently used to calculate temporal occupation and transformation values of soil into roadways. Transformation values can be incorporated into LCAs of this type of infrastructures, since they can be expressed in terms of vehicle flow. Finally, the need to consider the potential territorial fragmentation and implications on land productivity during road planning is highlighted.El término “uso del suelo” se ha utilizado tradicionalmente para denotar una clasificación de las actividades humanas que ocupan superficie de suelo. En el campo del Análisis del Ciclo de Vida (ACV), el término “uso del suelo” o “impacto de uso del suelo” ha sido utilizado para designar los impactos medioambientales referidos a ocupación y transformación física de áreas de terreno. Nuestro estudio está centrado en el cálculo de la ocupación superficial de terreno de las carreteras españolas, resaltando la disparidad de los resultados obtenidos según cuál haya sido la fuente de datos consultada. El valor de ocupación es utilizado posteriormente para calcular la ocupación temporal y la transformación de suelo a calzada. El valor de la transformación puede incorporarse a los efectos medioambientales que causa este tipo de infraestructura a la hora de realizar un ACV de la misma, ya que se puede expresar en función del flujo de vehículos. Finalmente, se destaca la necesidad de considerar la fragmentación de territorio que potencialmente puede causarse y sus implicaciones en la productividad del terreno cuando se planifica un vial