Quantum chemical investigation on iodine oxides and their role in the formation of atmospheric aerosols

En esta contribución se presenta un estudio teórico de diferentes reacciones químicas entre óxidos de iodo y agua que pueden contribuir a la formación de partículas en la atmósfera. Mediante el uso de cálculos quimicocuánticos ab initio con tratamiento de la correlación electrónica se han obtenido propiedades termodinámicas para caracterizar esas reaccione

Reflections on a Fellowship and Time as a DEI Coordinator with Oscar Fernandez

In this episode of PDXPLORES, Dr. Óscar Fernández, a contingent faculty member in University Studies at Portland State University, discusses his work during a diversity fellowship at UC Irvine. That work resulted in the forthcoming essay, Queering a Coordinator\u27s Diversity, Equity, and Illusion (DEI) Work in Academe: Disappointments, Self-Deceits, and Hopes Disclosed, to be published by the University of California Humanities Research Institute\u27s journal Foundry. Fernández opens up about his experiences as a DEI officer for University Studies, how that experience informed his essay, and thinking about DEI efforts within the context of higher education

Rapidly convergent quasi-periodic Green functions for scattering by arrays of cylinders---including Wood anomalies

This paper presents a full-spectrum Green function methodology (which is valid, in particular, at and around Wood-anomaly frequencies) for evaluation of scattering by periodic arrays of cylinders of arbitrary cross section-with application to wire gratings, particle arrays and reflectarrays and, indeed, general arrays of conducting or dielectric bounded obstacles under both TE and TM polarized illumination. The proposed method, which, for definiteness is demonstrated here for arrays of perfectly conducting particles under TE polarization, is based on use of the shifted Green-function method introduced in the recent contribution (Bruno and Delourme, Jour. Computat. Phys. pp. 262--290 (2014)). A certain infinite term arises at Wood anomalies for the cylinder-array problems considered here that is not present in the previous rough-surface case. As shown in this paper, these infinite terms can be treated via an application of ideas related to the Woodbury-Sherman-Morrison formulae. The resulting approach, which is applicable to general arrays of obstacles even at and around Wood-anomaly frequencies, exhibits fast convergence and high accuracies. For example, a few hundreds of milliseconds suffice for the proposed approach to evaluate solutions throughout the resonance region (wavelengths comparable to the period and cylinder sizes) with full single-precision accuracy

Disseny i desenvolupament de circuits d'altes prestacions en banda C per a la missió espacial CIMR (Copernicus Imaging Microwave Radiometer) de la ESA

The Arctic is region where deep changes are occurring which have direct repercussions on our weather and climate. CIMR, that stands for Copernicus Imaging Microwave Radiometer, is a mission that will carry a wide-swath conically-scanning multi-frequency microwave radiometer to provide observations of sea-surface temperature, sea-ice concentration and sea-surface salinity, among other sea-ice parameters. In particular, CIMR will highly respond to the requirements from Artic communities. Beyond the immensity of the project itself, SENER Aeroespacial has the chance to be part of such a great mission, together with great organisations such as Thales Alenia Space, OHB Italia and HPS Germany. In fact, SENER Aeroespacial is in charge of designing, prototyping and measuring the equipment that conform the receivers and the calibrators of the radiometer. These equipment are on-board satellite devices, thus a committed design and characterization must be considered regarding space conditions and variability. Through the development of this project, a straightforward explanation of the equipment that take part in the calibration and reception chain is proposed. Moreover, a high-performance design, analysis and prototyping of the receiver chain is proposed. In addition, a complete product development is designed from scratch to the manufacturing and testing of a characteristic prototype ready to be integrated in any RF chain.El Ártico es una región en la que se están produciendo cambios impactantes que repercuten directamente en el tiempo y en el clima. CIMR, cuyas siglas significan Copernicus Imaging Microwave Radiometer, es una misión que consiste en un radiómetro de microondas multifrecuencia de barrido cónico de gran alcance para proporcionar observaciones de la temperatura de la superficie del mar, la concentración de hielo marino y la salinidad de la superficie del mar, entre otros parámetros del hielo marino. En particular, CIMR responderá en gran medida a las necesidades de las múltiples comunidades del Ártico. Más allá de la inmensidad del proyecto en sí, SENER Aeroespacial tiene la oportunidad de formar parte de una misión tan importante, junto con distintivas organizaciones como Thales Alenia Space, OHB Italia y HPS Alemania. De hecho, SENER Aeroespacial se encarga de diseñar, prototipar y medir los equipos que conforman los receptores y los calibradores del radiómetro. Estos equipos son dispositivos embarcados en satélites, por lo que se debe considerar un diseño y caracterización comprometidos con las condiciones y variabilidad del espacio. Mediante el desarrollo de este proyecto se propone una explicación a grandes rasgos de los equipos que intervienen en la cadena de calibración y recepción. Además, se propone un diseño, análisis y prototipado de alto rendimiento de la cadena de recepción. Asimismo, se propone un desarrollo completo del producto desde su inicio hasta la fabricación y prueba de un prototipo característico listo para ser integrado en cualquier cadena de RF.L'Àrtic és una regió on s'estan produint canvis impactants que repercuteixen directament en el temps i el clima. CIMR, que significa Copernicus Imaging Microwave Radiometer, és una missió que consisteix en un radiòmetre de microones multifreqüència d'escombrat cònic de gran abast per proporcionar observacions de la temperatura de la superfície del mar, la concentració de gel marí i la salinitat de la superfície del mar, entre altres paràmetres del gel marí. En particular, CIMR respondrà en gran part a les necessitats de les múltiples comunitats de l'Àrtic. Més enllà de la immensitat del projecte en si, SENER Aeroespacial té l'oportunitat de formar part d'una missió molt important, juntament amb organitzacions distintives com Thales Alenia Space, OHB Italia i HPS Germany. De fet, SENER Aeroespacial s'encarrega de dissenyar, prototipar i mesurar els equips que conformen els receptors i els calibradors del radiòmetre. Aquests equips són dispositius embarcats en satèl·lits, per la qual cosa cal considerar un disseny i caracterització compromesos amb les condicions i la variabilitat de l'espai. Mitjançant el desenvolupament d'aquest projecte, es proposa una explicació a grans trets dels equips que intervenen a la cadena de calibratge i recepció. A més, es proposa un disseny, anàlisi i prototipat d'alt rendiment de la cadena de recepció. Així mateix, es proposa un desenvolupament complet del producte des del seu inici fins a la fabricació i prova d'un prototip característic llest per ser integrat a qualsevol cadena de RF

A new and direct process for the reduction of lead sulfide

The direct reduction of lead sulfide concentrates by iron was investigated. An oxygen-bearing flux was shown to be a necessary ingredient for complete reduction of the concentrate. The effects of time and temperature on lead recovery were studied. Only a trace amount of sulfur dioxide is evolved during reduction, which is in agreement with thermochemical calculations --Abstract, page ii

On the evaluation of quasi-periodic Green functions and wave-scattering at and around Rayleigh-Wood anomalies

This article presents full-spectrum, well-conditioned, Green-function methodologies for evaluation of scattering by general periodic structures, which remains applicable on a set of challenging singular configurations, usually called Rayleigh-Wood (RW) anomalies (at which the quasi-periodic Green function ceases to exist), where most existing quasi-periodic solvers break down. After reviewing a variety of existing fast-converging numerical procedures commonly used to compute the classical quasi-periodic Green-function, the present work explores the difficulties they present around RW-anomalies and introduces the concept of hybrid “spatial/spectral” representations. Such expressions allow both the modification of existing methods to obtain convergence at RW-anomalies as well as the application of a slight generalization of the Woodbury-Sherman-Morrison formulae together with a limiting procedure to bypass the singularities. (Although, for definiteness, the overall approach is applied to the scalar (acoustic) wave-scattering problem in the frequency domain, the approach can be extended in a straightforward manner to the harmonic Maxwell's and elasticity equations.) Ultimately, this thorough study of RW-anomalies yields fast and highly-accurate solvers, which are demonstrated with a variety of simulations of wave-scattering phenomena by arrays of particles, crossed impenetrable and penetrable diffraction gratings and other related structures. In particular, the methods developed in this article can be used to “upgrade” classical approaches, resulting in algorithms that are applicable throughout the spectrum, and it provides new methods for cases where previous approaches are either costly or fail altogether. In particular, it is suggested that the proposed shifted Green function approach may provide the only viable alternative for treatment of three-dimensional high-frequency configurations with either one or two directions of periodicity. A variety of computational examples are presented which demonstrate the flexibility of the overall approach

Signalling DNA Damage

During our lifetime, the genome is constantly being exposed to different types of damage caused either by exogenous sources (radiations and/or genotoxic compound) but also as byproducts of endogenous processes (reactive oxigen species during respiration, stalled forks during replication, eroded telomeres, etc). From a structural point of view, there are many types of DNA damage including single or double strand breaks, base modifications and losses or base-pair mismatches. The amount of lesions that we face is enormous with estimates suggesting that each of our 1013 cells has to deal with around 10.000 lesions per day [1]. While the majority of these events are properly resolved by specialized mechanisms, a deficient response to DNA damage, and particularly to DSB, harbors a serious threat to human health [2]. DSB can be formed [1] following an exposure to ionizing radiation (X- or γ-rays) or clastogenic drugs; [2] endogenously, during DNA replication, or [3], as a consequence of reactive oxygen species (ROS) generated during oxidative metabolism. In addition, programmed DSB are used as repair intermediates during V(D)J and Class-Switch recombination (CSR) in lymphocytes [3], or during meiotic recombination [4]. Because of this, immunodeficiency and/or sterility problems are frequently associated with DDR-related pathologies