An Efficient Pseudospectral Method for the Computation of the Self-force on a Charged Particle: Circular Geodesics around a Schwarzschild Black Hole

The description of the inspiral of a stellar-mass compact object into a massive black hole sitting at a galactic centre is a problem of major relevance for the future space-based gravitational-wave observatory LISA (Laser Interferometer Space Antenna), as the signals from these systems will be buried in the data stream and accurate gravitational-wave templates will be needed to extract them. The main difficulty in describing these systems lies in the estimation of the gravitational effects of the stellar-mass compact object on his own trajectory around the massive black hole, which can be modeled as the action of a local force, the self-force. In this paper, we present a new time-domain numerical method for the computation of the self-force in a simplified model consisting of a charged scalar particle orbiting a nonrotating black hole. We use a multi-domain framework in such a way that the particle is located at the interface between two domains so that the presence of the particle and its physical effects appear only through appropriate boundary conditions. In this way we eliminate completely the presence of a small length scale associated with the need of resolving the particle. This technique also avoids the problems associated with the impact of a low differentiability of the solution in the accuracy of the numerical computations. The spatial discretization of the field equations is done by using the pseudospectral collocation method and the time evolution, based on the method of lines, uses a Runge-Kutta solver. We show how this special framework can provide very efficient and accurate computations in the time domain, which makes the technique amenable for the intensive computations required in the astrophysically-relevant scenarios for LISA.Comment: 15 pages, 9 figures, Revtex 4. Minor changes to match published versio

Signatures of non-locality in the first-order coherence of the scattered light

The spatial coherence of an atomic wavepacket can be detected in the scattered photons, even when the center-of-mass motion is in the quantum coherent superposition of two distant, non-overlapping wave packets. Spatial coherence manifests itself in the power spectrum of the emitted photons, whose spectral components can exhibit interference fringes as a function of the emission angle. The contrast and the phase of this interference pattern provide information about the quantum state of the center of mass of the scattering atom.Comment: 5 pages, one figure, submitted to Laser Physics, special issue in memory of Herbert Walthe

Fourth order indirect integration method for black hole perturbations: even modes

On the basis of a recently proposed strategy of finite element integration in time domain for partial differential equations with a singular source term, we present a fourth order algorithm for non-rotating black hole perturbations in the Regge-Wheeler gauge. Herein, we address even perturbations induced by a particle plunging in. The forward time value at the upper node of the $(r^*,t)$ grid cell is obtained by an algebraic sum of i) the preceding node values of the same cell, ii) analytic expressions, related to the jump conditions on the wave function and its derivatives, iii) the values of the wave function at adjacent cells. In this approach, the numerical integration does not deal with the source and potential terms directly, for cells crossed by the particle world line. This scheme has also been applied to circular and eccentric orbits and it will be object of a forthcoming publication.Comment: This series of papers deals with EMRI for LISA. With the respect to the v1 version, the algorithm has been improved; convergence tests and references have been added; v2 is composed by 23 pages, and 6 figures. Paper accepted by Class. Quantum Gravity for the special issue on Theory Meets Data Analysis at Comparable and Extreme Mass Ratios (Capra and NRDA) at Perimeier Institute in June 201

On the staking of miniaturized air-breathing microbial fuel cells

This work focuses on the scale-up of the MFCs by miniaturization and multiplication strategy. Performances of five stacks containing 1, 2, 5, 8 and 16 MFCs were compared. Each stack was evaluated under individual, parallel and series electrical connection as well as for cascade or individual hydraulic connection. Cascade feeding mode with a tank per stack favours the COD removal when the number of MFCs in the stack increases. However, despite operating without COD limitations, the energy production was disadvantaged. By changing the feeding system of a tank per stack into an individual tank per MFC, the performance of the whole stack enhances considerably. Stacking in series can increase the voltage 6 times while stacking in parallel can increase the current output about 4 times. For example, 8 MFCs can achieve 2.03 V connected in series and 6.98 mA connected in parallel. In addition, the power can be increased up to about 10 times leading to a power range high enough for real life applications

¿Cómo explicar las ondas en la vida cotidiana y la ingeniería?

En la actualidad el mundo atraviesa por fenómenos físicos que intervienen directamente con la regularidad de su entorno, se pueden identificar entre ellos las ondas, las cuales acontecen a diario en cada etapa de la vida humana, pero, actúan como fenómenos invisibles porque muchas personas desconocen su procedencia y peor aún los efectos que causan en su ambiente, el presente artículo se realizó con la finalidad de mostrar la importancia, el comportamiento y las consecuencias que proponen las ondas en el planeta tierra; en la ingeniería las ondas juegan un papel importante porque ayudan a la interpretación del planeta, esta es solo una de las varias aplicaciones descritas en el presente artículo; en la vida cotidiana aunque se desconoce cuándo se observa una imagen se capta una onda de luz; son cosas tan sencillas en las que se aplica la existencia de las ondas que se deben considerar en la vida humana.Al realizar el presente artículo se tuvo en cuenta la previa investigación en la web y sobre todo en la base de datos de la Fundación Universitaria Del Área Andina

New prototypes for the isolation of the anodic chambers in microbial fuel cells

This work has been focused on the assessment of new prototypes of MFC in which a more strict separation of the anode and cathode compartments is looked for, in order to attain strict anaerobic conditions in the anode chamber and hence, avoid lack of efficiency due to the prevalence of non-electrogenic competing microorganisms and to optimize composition of the anolyte and catholyte. A cylinder reactor with an inner chamber with graphite bars acting as anodes and the outer one with a stainless steel tube acting as cathode was used in three different configurations and results obtained during lifetests are compared in terms of electricity production, cathode oxygen consumption and anode COD depletion. Separation between compartments was obtained by (a) a two faces cathode (prototype R1, in which the cathode faces both compartments of the MFC), (b) a single cathode (prototype R2, in which the surface facing the anode compartment is electrically isolated and the ionic circuit is virtually detached) and (c) a conventional PEM membrane (prototype R3). Results show that the three prototypes perform as MFC from the electric point of view and they are efficient in the degradation of the COD contained in wastewater. However, the efficiencies in the production of electricity are very different and the greater the isolation of the anodic compartment, the lower are the current intensities produced. These results are explained because of the higher resulting ohmic loses. This large increase in the cell potential mask the potential benefits searched for with the isolation of the anode chamber but, at the same time, it gives significant information about performance of MFC that can be used for future MFC miniaturization studies.Este trabajo se ha centrado en la evaluación de nuevos prototipos de MFC en los que se busca una separación más estricta de los compartimentos anódico y catódico, con el fin de conseguir unas condiciones anaeróbicas estrictas en la cámara anódica y así evitar la falta de eficiencia debido a la prevalencia de microorganismos competidores no electrogénicos y optimizar la composición del anolito y catolito. Se utilizó un reactor cilíndrico con una cámara interior con barras de grafito que actúan como ánodos y la exterior con un tubo de acero inoxidable que actúa como cátodo en tres configuraciones diferentes y se comparan los resultados obtenidos durante las pruebas de vida en términos de producción de electricidad, consumo de oxígeno del cátodo y DQO ​​del ánodo. agotamiento. La separación entre compartimentos se obtuvo mediante (a) un cátodo de dos caras (prototipo R1, en el que el cátodo se enfrenta a ambos compartimentos del MFC), (b) un solo cátodo (prototipo R2, en el que la superficie que mira al compartimento del ánodo está aislada eléctricamente y el circuito iónico está prácticamente separado) y (c) una membrana PEM convencional (prototipo R3). Los resultados muestran que los tres prototipos funcionan como MFC desde el punto de vista eléctrico y son eficientes en la degradación de la DQO contenida en las aguas residuales. Sin embargo, las eficiencias en la producción de electricidad son muy diferentes y cuanto mayor es el aislamiento del compartimento anódico, menores son las intensidades de corriente producidas. Estos resultados se explican debido a las mayores pérdidas óhmicas resultantes. Este gran aumento en el potencial de la celda enmascara los beneficios potenciales buscados con el aislamiento de la cámara del ánodo pero, al mismo tiempo

¿Cómo explicar las ondas en la vida cotidiana y la ingeniería?

En la actualidad el mundo atraviesa por fenómenos físicos que intervienen directamente con la regularidad de su entorno, se pueden identificar entre ellos las ondas, las cuales acontecen a diario en cada etapa de la vida humana, pero, actúan como fenómenos invisibles porque muchas personas desconocen su procedencia y peor aún los efectos que causan en su ambiente, el presente artículo se realizó con la finalidad de mostrar la importancia, el comportamiento y las consecuencias que proponen las ondas en el planeta tierra; en la ingeniería las ondas juegan un papel importante porque ayudan a la interpretación del planeta, esta es solo una de las varias aplicaciones descritas en el presente artículo; en la vida cotidiana aunque se desconoce cuándo se observa una imagen se capta una onda de luz; son cosas tan sencillas en las que se aplica la existencia de las ondas que se deben considerar en la vida humana.Al realizar el presente artículo se tuvo en cuenta la previa investigación en la web y sobre todo en la base de datos de la Fundación Universitaria Del Área Andina

Comparative assessment of global irradiation from a satellite estimate model (CM SAF) and on-ground measurements (SIAR): a Spanish case study

An analysis and comparison of daily and yearly solar irradiation from the satellite CM SAF database and a set of 301 stations from the Spanish SIAR network is performed using data of 2010 and 2011. This analysis is completed with the comparison of the estimations of effective irradiation incident on three different tilted planes (fixed, two axis tracking, north-south hori- zontal axis) using irradiation from these two data sources. Finally, a new map of yearly values of irradiation both on the horizontal plane and on inclined planes is produced mixing both sources with geostatistical techniques (kriging with external drift, KED) The Mean Absolute Difference (MAD) between CM SAF and SIAR is approximately 4% for the irradiation on the horizontal plane and is comprised between 5% and 6% for the irradiation incident on the inclined planes. The MAD between KED and SIAR, and KED and CM SAF is approximately 3% for the irradiation on the horizontal plane and is comprised between 3% and 4% for the irradiation incident on the inclined planes. The methods have been implemented using free software, available as supplementary ma- terial, and the data sources are freely available without restrictions

European traditional tomatoes galore: a result of farmers' selection of a few diversity-rich loci

[EN] The high phenotypic diversity observed among European traditional tomato varieties was created by traditional farmer-driven selection by inadvertently combining a very few polymorphic loci subjected to balancing selection. A comprehensive collection of 1254 tomato accessions, corresponding to European traditional and modern varieties, early domesticated varieties, and wild relatives, was analyzed by genotyping by sequencing. A continuous genetic gradient between the traditional and modern varieties was observed. European traditional tomatoes displayed very low genetic diversity, with only 298 polymorphic loci (95% threshold) out of 64 943 total variants. European traditional tomatoes could be classified into several genetic groups. Two main clusters consisting of Spanish and Italian accessions showed higher genetic diversity than the remaining varieties, suggesting that these regions might be independent secondary centers of diversity with a different history. Other varieties seem to be the result of a more recent complex pattern of migrations and hybridizations among the European regions. Several polymorphic loci were associated in a genome-wide association study with fruit morphological traits in the European traditional collection. The corresponding alleles were found to contribute to the distinctive phenotypic characteristic of the genetic varietal groups. The few highly polymorphic loci associated with morphological traits in an otherwise a low-diversity population suggests a history of balancing selection, in which tomato farmers likely maintained the morphological variation by inadvertently applying a high selective pressure within different varietal types.This work was supported by the European Commission H2020 research and innovation program through TRADITOM grant agreement no. 634561, G2P-SOL, grant agreement no. 677379, and HARNESSTOM grant agreement no. 101000716. MP is grateful to the Spanish Ministerio de Ciencia e Innovacion for a postdoctoral grant (IJC2019-039091-I/AEI/10.13039/501100011033).Blanca Postigo, JM.; Pons Puig, C.; Montero-Pau, J.; Sánchez-Matarredona, D.; Ziarsolo, P.; Fontanet, L.; Fisher, J.... (2022). European traditional tomatoes galore: a result of farmers' selection of a few diversity-rich loci. Journal of Experimental Botany. 73(11):3431-3445. https://doi.org/10.1093/jxb/erac07234313445731

Atlas of phenotypic, genotypic and geographical diversity present in the European traditional tomato

[EN] The Mediterranean basin countries are considered secondary centres of tomato diversification. However, information on phenotypic and allelic variation of local tomato materials is still limited. Here we report on the evaluation of the largest traditional tomato collection, which includes 1499 accessions from Southern Europe. Analyses of 70 traits revealed a broad range of phenotypic variability with different distributions among countries, with the culinary end use within each country being the main driver of tomato diversification. Furthermore, eight main tomato types (phenoclusters) were defined by integrating phenotypic data, country of origin, and end use. Genome-wide association study (GWAS) meta-analyses identified associations in 211 loci, 159 of which were novel. The multidimensional integration of phenoclusters and the GWAS meta-analysis identified the molecular signatures for each traditional tomato type and indicated that signatures originated from differential combinations of loci, which in some cases converged in the same tomato phenotype. Our results provide a roadmap for studying and exploiting this untapped tomato diversity.We thank Universitat Illes Balears, the Greek Gene Bank (GGB-NAGREF), Universita degli Studi Mediterranea Reggio Calabria, the CRB-Leg (INRA-GAFL)", the Genebank of CNR-IBBR (Bari, Italy) and ARCA 2010 for seed sharing. CNR-IBBR also acknowledges the seed donors, the Leibniz Institute of Plant Genetics and Crop Plant Research, Maria Cristina Patane (CNR-IBE, Catania, Italy) and La Semiorto Sementi SRL, as well as Mrs. Roberta Nurcato for technical assistance. IBMCP-UPV acknowledges Maurizio Calduch (ALCALAX) for technical assistance and Mario Fon for English grammar editing. This work was supported by European Commission H2020 research and innovation program through TRADITOM grant agreement No.634561, G2P-SOL, grant agreement No. 677379, and HARNESSTOM grant agreement No. 101000716. Clara Pons and Mariola Plazas are grateful to Spanish Ministerio de Ciencia e Innovacion for postdoctoral grants FJCI-2016-29118 and IJC2019-039091I/AEI/10.13039/501100011033; Joan Casals to a Serra Hunter Fellow at Universitat Politècnica de Catalunya.Pons Puig, C.; Casals, J.; Palombieri, S.; Fontanet, L.; Riccini, A.; Rambla Nebot, JL.; Ruggiero, A.... (2022). Atlas of phenotypic, genotypic and geographical diversity present in the European traditional tomato. Horticulture Research. 9:1-16. https://doi.org/10.1093/hr/uhac112116