Interplay of deep-marine sedimentary processes with seafloor morphology offshore Madeira Island (Central NE-Atlantic)

The deep-water sedimentary processes and morphological features offshore Madeira Island, located in the Central-NE Atlantic have been scantly studied. The analysis of new multibeam bathymetry, echo-sounder profiles and few multichannel seismic reflection profiles allowed us to identify the main geomorphologies, geomorphic processes and their interplay. Several types of features were identified below 3800 m water depth, shaped mainly by i) the interplay between northward-flowing Antarctic Bottom Water (AABW) and turbidity currents and ii) interaction of the AABW with oceanic reliefs and the Madeira lower slope. Subordinate and localized geomorphic processes consist of tectono-magmatic, slope instability, turbidity currents and fluid migration. The distribution of the morphological features defines three regional geomorphological sectors. Sector 1 represents a deep seafloor with its abyssal hills, basement highs and seamounts inherited from Early Cretaceous seafloor spreading. Sector 2 is exclusively shaped by turbidity current flows that formed channels and associated levees. Sector 3 presents a more complex morphology dominated by widespread depositional and erosional features formed by AABW circulation, and localized mixed contourite system developed by the interplay between the AABW circulation and WNW-ESE-flowing turbidite currents. The interaction of the AABW with abyssal hills, seamounts and basement ridges leads to the formation of several types of contourites: patch drifts, double-crest mounded bodies, and elongated, mounded and separated drifts. The patch drifts formed downstream of abyssal hills defining an previously unknown field of relatively small contourites. We suggest they may be a result of localized vortexes that formed when the AABW’s flow impinges these oceanic reliefs producingthe erosional scours that bound these features. The bottom currents in the area are known to be too weak (1–2 cm s− 1) to produce the patch drifts and scours. Therefore, we suggest that these features could be relics at present, having developed when the AABW was stronger than today, as during glacial/end of glacial stages

Simulación de un control de corriente Para un Inversor Trifásico Utilizando un Solo Sensor de Corriente

En este trabajo se presenta un control de corriente para un inversor trifásico alimentado en voltaje con cargas balanceadas, dicho control es llevado a cabo, utilizando un solo sensor de corriente, con la finalidad de tener un bajo costo en el control de un inversor trifásico. Así mismo, se describe el funcionamiento de este control, el cual se basa en el seguimiento de una señal de referencia senoidal y la utilización de los patrones de la técnica de modulación por espacio vectorial (SVPWM).Con base a esto, los resultados obtenidos de la simulación son mostrados, con el fin de evaluar la propuest

Contourite drift off Madeira Island (Northeast Atlantic) and implications to Cenozoic bottom-current circulation

EUROPEAN GEOPHYSICAL UNIO

CARGADOR DE BATERÍAS TRIFÁSICO CON ALTO FACTOR DE POTENCIA PARA VEHÍCULOS ELÉCTRICOS (THREE-PHASE BATTERY CHARGER WITH HIGH POWER FACTOR FOR ELECTRIC VEHICLES)

Resumen Con el avance de la tecnología se hace más notorio el uso de vehículos eléctricos que constituyen grandes cargas a la red eléctrica y requieren procesos de carga eficientes y con alto factor de potencia. En este artículo se propone un cargador de baterías trifásico constituido por un puente activo doble, un rectificador y un filtro, constituyendo un corrector del factor de potencia operando en modo de conducción discontinua. Para evaluar el desempeño se realizaron simulaciones en lazo cerrado del sistema propuesto, donde se aprecian las bondades del sistema. Palabras Clave: Cargador de baterías trifásico, vehículos eléctricos, factor de potencia, puente activo doble. Abstract The advancement of technology, the use of electric vehicles is increasing and they may constitute a large load in the electrical grid, they require efficient charging processes with high power factor. This work proposes a three-phase battery charger based on a double active bridge, a rectifier, and a filter; with a high power factor since it is operated in discontinuous conduction mode. The performance of the system is evaluated by close loop simulation, where the performance of the system is illustrated. Keywords: Three-phase battery charger, electric vehicles, power factor, double active bridge

Evaluation of Clinical and Immunopathological Features of Different Infective Doses of Trypanosoma cruzi in Dogs during the Acute Phase

Infection with Trypanosoma cruzi is a major risk in Latin America, and dogs are believed to be good models for evaluating Chagas disease. Here, we evaluated the clinical and immunopathological alterations developed by mongrel dogs experimentally infected with different infective doses (2,000, 20,000, and 200,000 metacyclic trypomastigotes of Sylvio X10/4 strain kg−1 via intraperitoneal). Clinical and electrocardiographic parameters, as well as antibody production and pathologic lesions were evaluated. All three doses of this strain of T. cruzi induced a similar pattern of infection characterized by cardiac arrhythmias and severe and diffuse myocarditis. Specific anti-T. cruzi IgG indicated seroconversion by day 14 after infection, and IgG levels increased during the period of evaluation. Mortality was observed only in dogs infected with the medium or high parasite doses, but not in the group infected with a low dose of 2,000 parasites kg−1. Infection with a low dose of parasites provides an excellent nonlethal model to evaluate the immunopathology of the acute disease in dogs infected with the Sylvio X10/4 strain of T. cruzi

SDSS-IV MaNGA : the MaNGA dwarf galaxy sample presentation

M.C.D. acknowledges support from CONACYT "Ciencia de Frontera" grant 320199. M.C.D. and H.M.H.T. acknowledge support from UC MEXUS-CONACYT grant CN-17-128. A.R.P. acknowledges support from the CONACyT "Ciencia Basica" grant 285721. E.A.O. acknowledges support from the SECTEI (Secretaría de Educación, Ciencia, Tecnología e Innovación de la Ciudad de México) under the Postdoctoral Fellowship SECTEI/170/2021 and CM-SECTEI/303/2021. Funding for the Sloan Digital Sky Survey IV has been provided by the Alfred P. Sloan Foundation, the U.S. Department of Energy Office of Science, and the Participating Institutions.We present the MaNGA Dwarf galaxy (MaNDala) Value Added Catalog (VAC), from the final release of the Sloan Digital Sky Survey-IV program. MaNDala consists of 136 randomly selected bright dwarf galaxies with M* −18.5, making it the largest integral field spectroscopy homogeneous sample of dwarf galaxies. We release a photometric analysis of the g, r, and z broadband imaging based on the DESI Legacy Imaging Surveys, as well as a spectroscopic analysis based on the Pipe3D SDSS-IV VAC. Our release includes the surface brightness (SB), geometric parameters, and color profiles, Sérsic fits as well as stellar population properties (such as stellar ages, metallicities, and star formation histories), and emission lines' fluxes within the FOV and the effective radii of the galaxies. We find that the majority of the MaNDala galaxies are star-forming late-type galaxies with 〈nSersic,r〉∼1.6 that are centrals (central/satellite dichotomy). MaNDala covers a large range of SB values (we find 11 candidate ultra-diffuse galaxies and three compact ones), filling the gap between classical dwarfs and low-mass galaxies in the Kormendy Diagram and in the size–mass/luminosity relation, which seems to flatten at 108 2, while the last 20% was at 〈z〉 < 0.3. Finally, a bending of the sSFR-M * relation at M* ∼ 109 M⊙ for the main-sequence galaxies seems to be supported by MaNDala.Publisher PDFPeer reviewe

Nuevo inversor fotovoltaico integrado sin transformador

Los inversores sin transformador son ampliamente utilizados en sistemas fotovoltaicos conectados a la red eléctrica, debido a los beneficios de lograr alta eficiencia y bajo costo.El inversor fotovoltaico sin transformador puede generar una corriente de fuga entre el inversor y la red eléctrica, a través de la capacitancia parásita del módulo fotovoltaico y la tierra física. Esta corriente de fuga provoca una disminución de la eficiencia, reduce el tiempo de vida del módulo fotovoltaico y pone en riesgo al personal que esté en contacto con el sistema. Se han propuesto varias topologías de inversores sin transformador para reducir esta corriente de fuga; este trabajo propone una topología diferente que consiste en la integración de dos etapas, un inversor puente completo y un convertidor CD/CD elevador. Una terminal de salida del inversor está conectada directamente a tierra y el convertidor es controlado por modos deslizantes.Palabra(s) Clave(s): control por modos deslizantes, corriente de fuga, inversor fotovoltaico

Sistema fotovoltaico multifuncional conectado a la red eléctrica controlado por medio de modos deslizantes

Debido al uso de cargas electrónicas no lineales, la calidad de la energía eléctrica se ha ido deteriorando. Con el creciente uso de fuentes renovables de energía interconectadas a la red eléctrica es posible integrar la función de los filtros activos de potencia a los sistemas fotovoltaicos (PV, por sus siglas en inglés) conectados a la red, modificando el control del convertidor. Debido a lo antes mencionado en este trabajo se propone el uso de un sistema PV controlado por medio de modos deslizantes, con una superficie deslizante capaz de inyectar tanto potencia activa como reactiva para eliminar los armónicos de corriente en el punto de acoplamiento común (PAC) y mantener un factor de potencia elevado aún ante la presencia de cargas no lineales, con la ventaja de una fácil implementación.El sistema es diseñado y simulado, con lo cual se confirma la eficacia del controlador por modos deslizantes propuesto. Además se mencionan las ventajas sobre los inversores PV convencionales.Palabra(s) Clave(s): control por modos deslizantes, inversor fotovoltaico, potencia activa, superficie de deslizamiento

SDSS-IV MaNGA: global and local stellar population properties of elliptical galaxies

We study the spatially resolved properties of 343 elliptical galaxies with the MaNGA/SDSS-IV survey. We used the DESI Legacy Imaging Surveys for morphological classification. Based on integrated spectroscopic properties and colors, we classified seven classes of ellipticals. We inferred the stellar age and metallicity ($Z$) gradients out to a 1.5 effective radius of classical "red and dead", recently quenched, and blue star-forming ellipticals (CLEs, RQEs, and BSFs), corresponding to 73%, 10%, and 4% of the sample, respectively. We reconstructed their global and radial histories of star formation and mass growth. We find the mass- and luminosity-weighted age gradients of CLEs are nearly flat or mildly negative. The respective $Z$ gradients are negative, being flatter as the mass is smaller. The more massive CLEs formed stars earlier and quenched faster than the less massive ones. The CLEs show a weak inside-out growth and a clear inside-out quenching. They finished their quenching globally 3.8 $\pm$ 1.2 Gyr ago, with quenching time-scales of 3.4 $\pm$ 0.8 Gyr. At masses < 10$^{11}$ $M_{\bigodot}$, the age and $Z$ gradients of the RQEs and BSFs are flatter than those of the CLEs but with larger scatters. They show very weak inside-out growth and quenching, which is slow and even not completed at $z\sim0$ for the BSFs. Instead, the massive RQEs show an outside-in quenching and positive gradients in the luminosity-weighted age and stellar metallicities. The RQEs of all masses quenched 1.2 $\pm$ 0.9 Gyr ago on average. Our results for the CLEs are consistent with a two-phase scenario where their inner parts formed by an early and coeval dissipative collapse with a consequent burst of star formation and further quenching, whereas the outer parts continued their assembly likely by dry mergers. We also discuss some evolutionary scenarios for the RQE and BSF galaxies.Comment: 24 pages and 18 figures without appendix. We added Table 1 with a list of acronyms. Original article published in Astronomy & Astrophysic