New four-dimensional integrals by Mellin-Barnes transform

This paper is devoted to the calculation by Mellin-Barnes transform of a especial class of integrals. It contains double integrals in the position space in d = 4-2e dimensions, where e is parameter of dimensional regularization. These integrals contribute to the effective action of the N = 4 supersymmetric Yang-Mills theory. The integrand is a fraction in which the numerator is a logarithm of ratio of spacetime intervals, and the denominator is the product of powers of spacetime intervals. According to the method developed in the previous papers, in order to make use of the uniqueness technique for one of two integrations, we shift exponents in powers in the denominator of integrands by some multiples of e. As the next step, the second integration in the position space is done by Mellin-Barnes transform. For normalizing procedure, we reproduce first the known result obtained earlier by Gegenbauer polynomial technique. Then, we make another shift of exponents in powers in the denominator to create the logarithm in the numerator as the derivative with respect to the shift parameter delta. We show that the technique of work with the contour of the integral modified in this way by using Mellin-Barnes transform repeats the technique of work with the contour of the integral without such a modification. In particular, all the operations with a shift of contour of integration over complex variables of two-fold Mellin-Barnes transform are the same as before the delta modification of indices, and even the poles of residues coincide. This confirms the observation made in the previous papers that in the position space all the Green function of N = 4 supersymmetric Yang-Mills theory can be expressed in terms of UD functions.Comment: Talk at El Congreso de Matematica Capricornio, COMCA 2009, Antofagasta, Chile and at DMFA seminar, UCSC, Concepcion, Chile, 24 pages; revised version, Introduction is modified, Conclusion is added, five Appendices are added, Appendix E is ne

Comparison of short-range-order in liquid- and rotator-phase states of a simple molecular liquid: A reverse Monte Carlo and molecular dynamics analysis of neutron diffraction data

6 págs.; 6 figs.; 1 tab. ; PACS number s : 61.25.Em, 61.20. p, 61.43. j, 61.12. qThe short-range order (SRO) correlations in liquid- and rotator-phase states of carbon tetrachloride are revisited here. The correlation of some angular magnitudes is used to evaluate the positional and orientational correlations in the liquid as well as in the rotator phase. The results show significant similitudes in the relative position of the molecules surrounding a central one but striking differences in their relative orientations, which could explain the changes in SRO between the two phases and the puzzling behavior of the local density in the liquid and rotator phases. © 2007 The American Physical Society.We would also like to acknowledge “Generalitat de Catalunya” Project No. 2005SGR- 00535 and MEC Project No. FIS2005-00975 for partial support of this work.Peer Reviewe

Unveiling hidden companions in post-common-envelope binaries: A robust strategy and uncertainty exploration

Some post-common-envelope binaries are binary stars with short periods that exhibit significant period variations over long observational time spans. These eclipse timing variations (ETVs) are most likely to be accounted for by the presence of an unseen massive companion, potentially of planetary or substellar nature, and the light-travel time (LTT) effect. In this study, our main objective is to describe the diversity of compatible nontransit companions around PCEBs and explore the robustness of the solutions by employing tools for uncertainty estimation. We select the controversial data of the QS Vir binary star, which previous studies have suggested hosts a planet. We employ a minimizing strategy, using genetic algorithms to explore the global parameter space followed by refinement of the solution using the simplex method. We evaluate errors through the classical MCMC approach and discuss the error range for parameters. Our results highlight the strong dependence of ETV models for close binaries on the dataset used, which leads to relatively loose constraints on the parameters of the unseen companion. We find that the shape of the $O-C$ curve is influenced by the dataset employed. We propose an alternative method to evaluate errors on the orbital fits based on a grid search surrounding the best-fit values, obtaining a wider range of plausible solutions that are compatible with goodness-of-fit statistics. We also analyze how the parameter solutions are affected by the choice of the dataset, and find that this system continuously changes the compatible solutions as new data are obtained from eclipses. The best-fit parameters for QS Vir correspond to a low-mass stellar companion (57.71 $M_{jup}$ ranging from 40 to 64 $M_{jup}$) on an eccentric orbit ($e=0.91^{+0.07}_{-0.17}$) with a variety of potential periods ($P = 16.69 ^{+0.47}_{-0.42}$ yr.)Comment: 13 Pages. 14 Figures. A&A A&A approved. article aa47030-2

Thermal torque effects on the migration of growing low-mass planets

As planets grow the exchange of angular momentum with the gaseous component ofthe protoplanetary disc produces a net torque resulting in a variation of the semi-major axis of the planet. For low-mass planets not able to open a gap in the gaseousdisc this regime is known as type I migration. Pioneer works studied this mechanismin isothermal discs finding fast inward type I migration rates that were unable toreproduce the observed properties of extrasolar planets. In the last years, several im-provements have been made in order to extend the study of type I migration rates tonon-isothermal discs. Moreover, it was recently shown that if the planet?s luminositydue to solid accretion is taken into account, inward migration could be slowed downand even reversed. In this work, we study the planet formation process incorporating,and comparing, updated type I migration rates for non-isothermal discs and the role ofplanet?s luminosity over such rates. We find that the latter can have important effectson planetary evolution, producing a significant outward migration for the growingplanets.Fil: Guilera, Octavio Miguel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Astrofísica La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas. Instituto de Astrofísica La Plata; ArgentinaFil: Cuello, N.. Pontificia Universidad Católica de Chile; ChileFil: Montesinos, M.. Universidad de Valparaíso; ChileFil: Miller Bertolami, Marcelo Miguel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Astrofísica La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas. Instituto de Astrofísica La Plata; ArgentinaFil: Ronco, María Paula. Pontificia Universidad Católica de Chile; Chile. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Astrofísica La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas. Instituto de Astrofísica La Plata; ArgentinaFil: Cuadra, J.. Pontificia Universidad Católica de Chile; ChileFil: Masset, F. S.. Universidad Autonoma de Mexico; Méxic

Formation of misaligned second-generation discs through fly-by encounters

Observations reveal protoplanetary discs being perturbed by fly-by candidates. We simulate a scenario where an unbound perturber, i.e. a fly-by, undergoes an inclined grazing encounter, capturing material and forming a second-generation protoplanetary disc. We run N-body and three-dimensional hydrodynamical simulations of a parabolic fly-by grazing a particle disc and a gas-rich protoplanetary disc, respectively. In both our N-body and hydrodynamic simulations, we find that the captured, second-generation disc forms at a tilt twice the initial fly-by tilt. This relationship is robust to variations in the fly-by’s tilt, position angle, periastron, and mass. We extend this concept by also simulating the case where the fly-by has a disc of material prior to the encounter but we do not find the same trend. An inclined disc with respect to the primary disc around a misaligned fly-by is tilted by a few degrees, remaining close to its initial disc tilt. Therefore, if a disc is present around the fly-by before the encounter, the disc may not tilt up to twice the perturber tilt depending on the balance between the angular momentum of the circumsecondary disc and captured particles. In the case where the perturber has no initial disc, analysing the orientation of these second-generation discs can give information about the orbital properties of the fly-by encounter

Submarine outfall of Mar del Plata (Argentina) : how did the construction impact on the intertidal benthic community?

Una solución adecuada al problema que deben resolver muchos países con respecto al tratamiento y el vertido de aguas cloacales, y su potencial impacto sobre el ambiente, podría ser verterlas por medio de emisarios submarinos. Hasta diciembre de 2014, los residuos cloacales de Mar del Plata se vertían de forma directa a la zona intermareal, sin tratamiento previo. En el año 2009 se comenzó a construir el emisario submarino (ES); la obra se inició con la incorporación de dos escolleras de abrigo y un frente de atraque. El ES, inaugurado en diciembre del 2014, descarga las aguas residuales sobre el submareal (4 km mar adentro). El objetivo de este trabajo fue evaluar los cambios en la estructura de la comunidad bentónica intermareal durante las distintas fases del proceso de construcción del ES (Antes, Durante y Después). Se consideraron tres sitios de muestreo localizados a diferentes distancias del efluente cloacal. Los resultados mostraron cambios en la comunidad bentónica intermareal como respuesta a la puesta en funcionamiento del ES. La abundancia de las especies sensibles a la contaminación aumentó en la etapa posterior a la puesta en funcionamiento del ES. Si bien la riqueza de especies alcanzó su pico máximo durante la fase de construcción del ES, la equitatividad y la diversidad aumentaron en la etapa posterior. Se observaron agrupamientos según la similitud en la composición específica según el factor etapa (Antes). Sin embargo, no se observaron agrupamientos con respecto a los sitios. En conclusión, los resultados obtenidos mostraron los cambios ocurridos en la estructura comunitaria intermareal asociados al nuevo vertido de aguas residuales generado por el emisario submarino construido en la ciudad.An adequate solution to the problem many countries must solve with respect to the treatment and discharge of sewage water, and its potential impacts on the environment, could be discharging them by means of submarine outfalls. Until December 2014, wastewater from Mar del Plata city was discharged untreated directly to the intertidal zone. In 2009, the construction of the submarine outfall (SO) began; two breakwaters and a docking front were built. The SO was inaugurated in December 2014 and the wastewater discharges directly over the subtidal (4 km offshore). The aim of this study was to evaluate the changes in the structure of the intertidal benthic community during the different phases of the SO construction [Before (A), During (Du) and After (De)]. Three sampling sites were located at different distances from the sewage effluent. The results showed changes in the intertidal benthic community in response to the functioning of the SO. The abundance of species sensitive to pollution increased in the posterior phase of the SO construction. Although the species richness peaked during the construction phase of the ES, evenness and diversity index increased in the subsequent phase (After). Groupings were observed according to the similarity in the specific composition according to the phase factor (Before, During and After). However, grouping of species according to the sites were not observed. In conclusion, the results obtained showed the changes occurred in the intertidal community structure associated with the new wastewater discharge generated by the submarine outfall built in the city

Insecticidas con posibilidad de registro en cereza en Argentina y sus implicancias para la exportación de frutas frescas

En la Norpatagonia argentina se observa, en los últimos 5 años, un constante incremento de la superficie cultivada con cerezos. Ligado a esto, se registra un aumento de la incidencia de plagas que obliga a realizar tratamientos de control específico. En la actualidad el número de insecticidas registrados para dicho cultivo es muy escaso y no siempre tiene relación con la eficacia de control de las plagas presentes. Además, el comercio internacional de frutos frescos requiere del conocimiento de la declinación de los plaguicidas para alcanzar las tolerancias establecidas por cada país comprador y los estándares secundarios de comercialización, si existieran. El objetivo del presente trabajo es analizar la declinación de seis insecticidas de posible uso según las plagas presentes en la región y determinar sus implicancias en el intercambio comercial de ultramar. Los insecticidas estudiados fueron: abamectina, benzoato de emamectina, lambdacialotrina, spinetoram, spirotetramate y metomil. La fruta pulverizada y cosechada a diferentes períodos luego de la aplicación, en la localidad de Contralmte. Guerrico, fue analizada por cromatografía de gases con detector de masas-masas (GC-MS-MS) con un límite de cuantificación (LC) de 0,01 mg/kg y de detección (LD) de 0,005 mg/kg. La mayoría de los insecticidas evaluados en frutas de cereza resultaron no detectables a los 45 días, a excepción del spirotetramate (0,01 ppm) y lambdacialotrina (0,03 ppm). A los 14 días de la pulverización, los residuos de abamectina, benzoato de emamectina y spinetoram declinaron a valores inferiores a 0,01 ppm. Cada uno de estos insecticidas posee diferentes tipos de limitaciones de uso en cuanto a su registro y tolerancia en los países a los cuales se desea exportar cerezas. Se realiza un análisis particular en cada uno de ellos. Por una parte, esta información es relevante, especialmente luego de la reciente introducción a la región de la plaga exótica Drosophila suzukii. El ciclo productivo del cultivo de cerezos es corto y la plaga afecta los frutos desde el envero hasta el final de la cosecha, por esta razón el conocimiento de la declinación de los insecticidas eficaces para su control debe ser muy preciso. Por otra parte, es indispensable diseñar estrategias de intervención sanitarias integrando diferentes tipos de herramientas, asegurando un manejo adecuado de la resistencia a los plaguicidas.In the Argentine Norpatagonia, a constant increase of the cherry production area has been observed in the last 5 years. Linked to this, there is an increase in the incidence of pests that requires specific control treatments. Currently, the number of insecticides registered for this crop is very low and in some cases it is not related to the effectiveness of control of the present pests. In addition, the international trade of fresh fruits requires knowledge of the decline of pesticides to reach the tolerances established by each buyer country and the secondary residue standards of commercialization if they exist. The objective of the present work is to analyze the decline of six insecticides of possible use according to the pests present in the region, and to determine their implications in the overseas commercial exchange. The insecticides studied were: abamectin, emamectin benzoate, lambdacyhalothrin, spinetoram, spirotetramate and methomyl. The fruit, pulverized and harvested at different periods after application, in Cmte Guerrico area, was analyzed by gas chromatography with mass-mass detector (GC-MS-MS) with a limit of quantification (LC) of 0.01 mg / kg and detection (LD) of 0.005 mg / kg. Most of the insecticides evaluated in sweet cherry fruits were found to be non-detectable at 45 days, with the exception of spirotetramate (0.01 ppm) and lambdacyhalothrin (0.03 ppm). At 14 days after spraying, the residues of abamectin, emamectin benzoate and spinetoram declined to values below 0.01 ppm. Each of these insecticides has different types of use limitations in terms of their registration and tolerance in the countries to which they wish to export sweet cherries. A particular analysis is carried out in each of them. This information is relevant, especially after the recent introduction to the region, of the exotic pest Drosophila suzukii. The productive cycle of the cherry cultivation is short and the pest affects the fruits from the veraison until the end of the harvest, for this reason the knowledge of the decline of the effective insecticides for its con­trol, must be very precise. On the other hand, it is essential to design health intervention strategies integrating different types of tools, ensuring adequate management of resistance.EEA Alto ValleFil: Cichón, Liliana Isabel. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Alto Valle; ArgentinaFil: Araque, Liliana. Centro de Investigación y Asistencia Técnica a la Industria (Asociación Civil); ArgentinaFil: Garrido, Silvina Alejandra. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Alto Valle; ArgentinaFil: Lago, Jonatan Daniel. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Alto Valle; ArgentinaFil: Cuello, N. Centro de Investigación y Asistencia Técnica a la Industria (Asociación Civil); Argentin

Temperature and time dependent structure of the molten Ni81P19 alloy by neutron diffraction

The temperature and time dependent structure of molten NiP alloy of eutectic composition has been studied by neutron diffraction. Ni particles were found to exist in the melt at temperatures at least up to about 150 degrees above liquidus. The amount varies reversibly as temperature increases but decays slowly with time. Remarkably, particles still exist even after that the melt has been kept more than 30 h at different temperatures in the molten state. The static structure factor and the pair distribution function obtained at 1050 °C are presented

Circumbinary, not transitional: on the spiral arms, cavity, shadows, fast radial flows, streamers, and horseshoe in the HD 142527 disc

We present 3D hydrodynamical models of the HD142527 protoplanetary disc, a bright and well-studied disc that shows spirals and shadows in scattered light around a 100 au gas cavity, a large horseshoe dust structure in mm continuum emission, together with mysterious fast radial flows and streamers seen in gas kinematics. By considering several possible orbits consistent with the observed arc, we show that all of the main observational features can be explained by one mechanism - the interaction between the disc and the observed binary companion. We find that the spirals, shadows, and horseshoe are only produced in the correct position angles by a companion on an inclined and eccentric orbit approaching periastron - the 'red' family from Lacour et al. Dust-gas simulations show radial and azimuthal concentration of dust around the cavity, consistent with the observed horseshoe. The success of this model in the HD142527 disc suggests other mm-bright transition discs showing cavities, spirals, and dust asymmetries may also be explained by the interaction with central companions