Self-consistency in Theories with a Minimal Length

The aim of this paper is to clarify the relation between three different approaches of theories with a minimal length scale: A modification of the Lorentz-group in the 'Deformed Special Relativity', theories with a 'Generalized Uncertainty Principle' and those with 'Modified Dispersion Relations'. It is shown that the first two are equivalent, how they can be translated into each other, and how the third can be obtained from them. An adequate theory with a minimal length scale requires all three features to be present.Comment: typos corrected, published with new title following referee's advic

Use of a hydrodynamic model for the management of water renovation in a coastal system

In this contribution we investigate the hydrodynamic response in Alfacs Bay (Ebro Delta, NW Mediterranean Sea) to different anthropogenic modifications in freshwater flows and inner bay–open sea connections. The fresh water coming from rice field irrigation contains nutrients and pesticides and therefore affects in multiple ways the productivity and water quality of the bay. The application of a nested oceanographic circulation modelling suite within the bay provides objective information to solve water quality problems that are becoming more acute due to temperature and phytoplankton concentration peaks during the summer period when seawater may exceed 28&thinsp;∘C, leading to high rates of mussel mortality and therefore a significant impact on the local economy. The effects of different management “solutions” (like a connection channel between the inner bay and open sea) are hydrodynamically modelled in order to diminish residence times (e-flushing time) and water temperatures. The modelling system, based on the Regional Ocean Modeling System (ROMS), consists of a set of nested domains using data from CMEMS-IBI for the initial and open boundary conditions (coarser domain). One full year (2014) of simulation is used to validate the results, showing low errors with sea surface temperature (SST) and good agreement with surface currents. Finally, a set of twin numerical experiments during the summer period (when the water temperature reaches 28&thinsp;∘C) is used to analyse the effects of proposed nature-based interventions. Although these actions modify water temperature in the water column, the decrease in SST is not enough to avoid high temperatures during some days and prevent eventual mussel mortality during summer in the shallowest regions. However, the proposed management actions reveal their effectiveness in diminishing water residence times along the entire bay, thus preventing the inner areas from having poor water renewal and the corresponding ecological problems.</p

Nuclear recoil measurements in Superheated Superconducting Granule detectors

The response of Superheated Superconducting Granule (SSG) devices to nuclear recoils has been explored by irradiating SSG detectors with a 70Me$\!$V neutron beam. In the past we have tested Al SSG and more recently, measurements have been performed with Sn and Zn detectors. The aim of the experiments was to test the sensitivity of SSG detectors to recoil energies down to a few ke$\!$V. In this paper, the preliminary results of the neutron irradiation of a SSG detector made of Sn granules 15-20$\mu$m in diameter will be discussed. For the first time, recoil energy thresholds of $\sim$1ke$\!$V have been measured.Comment: 7pages in Latex format, Preprint Bu-He 93/6 (University of Berne, Switzerland), four figures available upon request via [email protected] or [email protected]

La Directiva Europea sobre el Horario de Trabajo y su impacto sobre la formación quirúrgica. Resultados de una encuesta entre los residentes de Cirugía Cardiovascular en España

ObjetivosLa Directiva Europea del Horario de Trabajo (European Working time Directive [EWTD]) de 1993 debería estar en funcionamiento para cirujanos cardiovasculares y residentes en agosto de 2009, como respuesta a las dudas sobre la calidad del cuidado del paciente y la calidad de vida de los profesionales causadas por el trabajo excesivo y la fatiga laboral. Hay temor al impacto negativo de la fatiga en la calidad de la atención al paciente y de las residencias quirúrgicas, en especial en Cirugía Cardiovascular. Evaluamos el nivel de conocimiento de los residentes españoles sobre la EWTD.MétodosEncuesta individual a los residentes asistentes al XIII Curso de Residentes de la Sociedad Española de Cirugía Torácica y Cardiovascular de mayo de 2008. Incluye un resumen de los objetivos principales de la EWTD.ResultadosAsistieron 58 de 70 residentes posibles. La encuesta fue completada por 26. El 92,3% no había leído la EWTD y el 26,9% no tenía el mínimo conocimiento. El 54,2% estaba de acuerdo con su contenido; 53,8% la considera incompatible con su modelo ideal de formación; 68% cree que tendrá impacto negativo en la misma; 87% cree que discrimina a los residentes quirúrgicos; 65,2% cree que reducirá sus ingresos anuales; 84,6% cree que parte de la plantilla de sus servicios se opondrá.ConclusionesExiste un desconocimiento muy importante sobre la EWTD por los residentes españoles de Cirugía Cardiovascular. Sorprendentemente, la mayoría está de acuerdo con la EWTD a pesar de que pueda tener impacto negativo en su formación y retribución económica. Se requiere una profunda reflexión por parte de las sociedades profesionales sobre este tema para promover y proteger la formación en nuestra especialidad.ObjectivesThe 1993 European Working Time Directive (EWTD) should be implemented to its entirety for cardiovascular surgeons and residents by August 2009 as an answer to the concern about patient care and quality of life of professionals caused by fatigue and excessive continuous work. Great concern rose regarding its negative impact in the quality of surgical residencies, specifically in cardiovascular surgery. Our objective was to assess the knowledge of Spanish Cardiovascular Surgery residents on the EWTD and their level of agreement with its content.MethodsA survey questionnaire was given to all residents attending the XIII Annual Course organized by the Spanish Society of Thoracic-Cardiovascular Surgery in May 2008. It included a brief summary of the key features of the EWTD.ResultsOut of 70 eligible residents, 58 attended. Of these, 26 completed and returned the survey. 92,3% never read and 26,9% knew absolutely nothing about the EWTD. 54,2% agreedwith its content; 53,8% think it is not compatible with their ideal training model; 68% believe it will have a negative impact on their training; 87% think it negatively discriminates surgical residents; 65,2% believe it will decrease their annual stipends; 84,6% think it will find the opposition of part of the staff in their respective departments.ConclusionsKnowledge about the contents of the EWTD among Spanish Cardiovascular Surgery residents is scarce. The majority of them agree with the EWTD even realizing it may have a negative impact on training quality and economic retribution. A deep reflection on this by national and European societies to protect and promote the quality of the training in our specialty is required

CONNECTIVITY BETWEEN POPULATIONS OF THE MARINE CRAB LIOCARCINUS DEPURATOR IN THE ATLANTO-MEDITERRANEAN TRANSITION: A FIVE YEAR SERIES

Abstract: We carried out a spatial and temporal genetic differentiation analysis using seven populations of the marine crab Liocarcinus depurator to elucidate the effect of three oceanographic discontinuities in the Atlanto-Mediterranean coast: Gibraltar Strait, Almeria-Oran Front and Ibiza Channel. To conduct this study, a 527 bp fragment of the mitochondrial COI gene was sequenced in individuals captured in the period 2014-2018 from the following Iberian coast populations: Cádiz, West Alboran, East Alboran, Alacant, Valencia, Ebro Delta and North Catalonia. Two haplogroups were detected; one characteristic of Atlantic waters and the other of Mediterranean. Their differential distribution allowed understanding the connectivity between populations. The effect of the oceanographic fronts on gene flow varied over time. Their effects were significant for the Gibraltar Strait (2014 and 2017), Almeria Oran Front (2013, 2014, 2015, 2016 and 2017) and Ibiza Channel (2015). Interestingly, the joint analysis of West Alboran, East Alboran and Alacant populations allowed a more precise detection of the location of the Almeria Oran Front biological effects. Finally, significant differences were observed in connectivity between Valencia and Ebro Delta in 2015, although there is not an oceanographic discontinuity between them. The main conclusion is that the gene flow is mediated by oceanographic fronts, but their intensity and effects change over time.CTM2017-88080 AEI/FEDER, UE) (CTM2015-66400-C3-3-R MINECO/FEDER) (2017 SGR 1120)

Assessment of variability sources in grape ripening parameters by using FTIR and multivariate modelling

The variability in grape ripening is associated with the fact that each grape berry undergoes its own biochemical processes. Traditional viticulture manages this by averaging the physicochemical values of hundreds of grapes to make decisions. However, to obtain accurate results it is necessary to evaluate the different sources of variability, so exhaustive sampling is essential. In this article, the factors “grape maturity over time” and “position of the grape” (both in the grapevine and in the bunch/cluster) were considered and studied by analyzing the grapes with a portable ATR-FTIR instrument and evaluating the spectra obtained with ANOVA–simultaneous component analysis (ASCA). Ripeness over time was the main factor affecting the characteristics of the grapes. Position in the vine and in the bunch (in that order) were also significantly important, and their effect on the grapes evolves over time. In addition, it was also possible to predict basic oenological parameters (TSS and pH with errors of 0.3 °Brix and 0.7, respectively). Finally, a quality control chart was built based on the spectra obtained in the optimal state of ripening, which could be used to decide which grapes are suitable for harvest

Brownian Carnot engine

The Carnot cycle imposes a fundamental upper limit to the efficiency of a macroscopic motor operating between two thermal baths. However, this bound needs to be reinterpreted at microscopic scales, where molecular bio-motors and some artificial micro-engines operate. As described by stochastic thermodynamics, energy transfers in microscopic systems are random and thermal fluctuations induce transient decreases of entropy, allowing for possible violations of the Carnot limit. Despite its potential relevance for the development of a thermodynamics of small systems, an experimental study of microscopic Carnot engines is still lacking. Here we report on an experimental realization of a Carnot engine with a single optically trapped Brownian particle as working substance. We present an exhaustive study of the energetics of the engine and analyze the fluctuations of the finite-time efficiency, showing that the Carnot bound can be surpassed for a small number of non-equilibrium cycles. As its macroscopic counterpart, the energetics of our Carnot device exhibits basic properties that one would expect to observe in any microscopic energy transducer operating with baths at different temperatures. Our results characterize the sources of irreversibility in the engine and the statistical properties of the efficiency -an insight that could inspire novel strategies in the design of efficient nano-motors.Comment: 7 pages, 7 figure

Un estudio sobre la evaluación de libros didácticos

El libro de texto o libro didáctico ha sido utilizado como un recurso pedagógico que la mayoría de las veces define la secuencia de contenidos que se trabajan en las clases de ciencias. Por esa razón en estos últimos años ha adquirido una  gran importancia el desarrollo de criterios de evaluación de los libros de texto. Uno de los principales objetivos de este trabajo es ofrecer al profesorado un conjunto de criterios que les permita seleccionar el material didáctico que refleje claramente y se adecue al máximo posible a la realidad de su aula. En este trabajo presentamos un análisis comparativo inicial entre los libros de texto de conocimiento del medio de primaria españoles y de ciencias de la enseñanza fundamental brasileños. Inicialmente se diseñó una ficha de evaluación preliminar con 88 ítems, distribuidos en 6 categorías diferentes lo que permitió un análisis preliminar de los libros didácticos de ciencias españoles y brasileños. Se seleccionaron para el estudio los libros de texto más utilizados en los dos países y realizamos un análisis comparativo, basados en los criterios preliminares presentados en la ficha, con la finalidad de determinar el tratamiento que se daba a los contenidos relacionados con la salud. Evaluamos la utilización de la ficha como instrumento de análisis y determinamos un conjunto de criterios que pueden ser usados como indicadores en la evaluación de los contenidos de salud en los libros de texto de ciencias o conocimiento del medio de ambos países. Uno de  los resultados preliminares, nos muestra que la ficha de evaluación, a pesar de su extensión y presentar un amplio número de criterios, no tiene la función de establecer una clara diferenciación entre las obras analizadas. En estos libros se ha podido apreciar de manera clara la influencia de las directrices curriculares nacionales, los Parâmetros Curriculares Nacionales (PCN), en Brasil, y los Diseños Curriculares Base, en España. Estos definen entre otros aspectos el formato y la selección de contenidos que son seguidos por los diferentes autores y editoriales. Ambas directrices son orientaciones definidas por los Ministerios de Educación de cada país y que recomiendan, pero sin la fuerza de las leyes, la selección de contenidos, los principios psico-pedagógicos y las metodologías usadas en los libros didácticos de ciencia

High-Energy gamma-ray Astronomy and String Theory

There have been observations, first from the MAGIC Telescope (July 2005) and quite recently (September 2008) from the FERMI Satellite Telescope, on non-simultaneous arrival of high-energy photons from distant celestial sources. In each case, the highest energy photons were delayed, as compared to their lower-energy counterparts. Although the astrophysics at the source of these energetic photons is still not understood, and such non simultaneous arrival might be due to non simultaneous emission as a result of conventional physics effects, nevertheless, rather surprisingly, the observed time delays can also fit excellently some scenarios in quantum gravity, predicting Lorentz violating space-time "foam" backgrounds with a non-trivial subluminal vacuum refractive index suppressed linearly by a quantum gravity scale of the order of the reduced Planck mass. In this pedagogical talk, I discuss the MAGIC and FERMI findings in this context and I argue on a theoretical model of space-time foam in string/brane theory that can accommodate the findings of those experiments in agreement with all other stringent tests of Lorentz invariance. However, I stress the current ambiguities/uncertainties on the source mechanisms, which need to be resolved first before definite conclusions are reached regarding quantum gravity foam scenarios.Comment: 34 pages latex, 12 eps figures incorporated, uses special macros. Based on invited plenary talk at DICE 2008 Conference (Castiglioncello, Italy), September 22-26 200