Gamma-ray triangles: a possible signature of asymmetric dark matter in indirect searches

We introduce a new type of gamma-ray spectral feature, which we denominate gamma-ray triangle. This spectral feature arises in scenarios where dark matter self-annihilates via a chiral interaction into two Dirac fermions, which subsequently decay in flight into another fermion and a photon. The resulting photon spectrum resembles a sharp triangle and can be readily searched for in the gamma-ray sky. Using data from the Fermi-LAT and H.E.S.S. instruments, we find no evidence for such spectral feature and therefore set strong upper bounds on the corresponding annihilation cross section. A concrete realization of a scenario yielding gamma-ray triangles consists of an asymmetric dark matter model where the dark matter particle carries lepton number. We show explicitly that this class of models can lead to intense gamma-ray spectral features, potentially at the reach of upcoming gamma-ray telescopes, opening a new window to explore asymmetric dark matter through indirect searches.Comment: 11 pages, 6 figures. Published versio

Signatures from Scalar Dark Matter with a Vector-like Quark Mediator

We present a comprehensive study of a model where the dark matter is composed of a singlet real scalar that couples to the Standard Model predominantly via a Yukawa interaction with a light quark and a colored vector-like fermion. A distinctive feature of this scenario is that thermal freeze-out in the early universe may be driven by annihilation both into gluon pairs at one-loop ($gg$) and by virtual internal Bremsstrahlung of a gluon ($q \bar{q} g$). Such a dark matter candidate may also be tested through direct and indirect detection and at the LHC; viable candidates have either a mass nearly degenerate with that of the fermionic mediator or a mass above about 2 TeV.Comment: 30 pages, 10 figures. Matches published versio

Tensión superficial de las mezclas O2-Ar, N2-Ar y O2-N2-Ar

articulo de investigacionThe surface tension of some binary and ternary mixtures was calculated by means of molecular dynamics simulations in a canonical set. The analyzed mixtures were oxygen-argon, nitrogen-argon and oxygen-nitrogenargon. The force field for argon was recalculated in order to reproduce the experimental surface tension. The corresponding force fields for O2 and N2 were taken from a previous work [Mol. Simul. 45 (2019) 958-966], where it was shown that such force fields reproduce the experimental surface tension curves, as pure fluids. The nitrogen-argon surface tension was calculated for several mole fractions of argon. The obtained curve was compared with those experimental data and a good agreement was found. The standard Lorentz-Berthelot combining rules were employed. For the oxygen-argon mixture it was necessary to modify the cross term of the combining rules in order to reproduce theoretical and experimental data. The surface tension of the ternary mixture was also estimated varying the mole fraction of argon at a certain concentration of oxygen and nitrogen, previously adjusted. Several temperatures were used in order to show a tendency mostly at relatively low temperatures. After comparing the available experimental data, which are scarce, a good agreement was observed

A Novel PMSM Hybrid Sensorless Control Strategy for EV Applications Based on PLL and HFI

In this paper, a novel hybrid sensorless control strategy for Permanent Magnet Synchronous Machine (PMSM) drives applied to Electric Vehicles (EV) is presented. This sensorless strategy covers the EV full speed range and also has speed reversal capability. It combines a High Frequency Injection (HFI) technique for low and zero speeds, and a Phase-Locked Loop (PLL) for the medium and high speed regions. A solution to achieve smooth transitions between the PLL and the HFI strategies is also proposed, allowing to correctly detect the rotor position polarity when HFI takes part. Wide speed and torque four-quadrant simulation results are provided, which validate the proposed sensorless strategy for being further implemented in EV.Peer ReviewedPostprint (author's final draft

IPMSM torque control strategies based on LUTs and VCT feedback for robust control under machine parameter variations

In recent years, Interior Permanent Magnet Synchronous Machines (IPMSMs) have attracted a considerable attention in the scientific community and industry for Electric and Hybrid Electric Vehicle (HEV) propulsion systems. Lookup Table (LUT) based Field Oriented Control (FOC) strategies are widely used for IPMSM torque control. However, LUTs strongly depend on machine parameters. Deviations of these parameters due to machine ageing, temperature or manufacturing inaccuracies can lead to control instabilities in the field weakening region. In this paper, two novel hybrid IPMSM control strategies combining the usage of LUTs and Voltage Constraint Tracking (VCT) feedbacks are proposed in order to overcome the aforementioned controllability issues. Simulation results that demonstrate the validity of the proposed approaches are presented.Postprint (author's final draft

Separación de azucares por medio de resinas de intercambio iónico.

Este trabajo se enfoca en una investigación sobre el uso de la resina de intercambio iónico "Diualón SK 110" en la separación de diferentes azúcares como un medio de facilitar su análisis. Esencialmente la separación consiste en : la absorción diferencial sobre distintas zonas de la colunna de resina, La elución con un solvente adecuado, en este caso, agua. Durante la elución los azúcares fluyen individualmente en distintas fracciones de solvente, permitiendo su identificación cualitativa y determinación cuantitativa por procedimientos convencionales

Vegetation Changes Ten Years after Catclaw Mimosa ( \u3cem\u3e Mimosa laxiflora \u3c/em\u3e ) Control with Tebuthiuron in a Short Grass Prairie at Northern Sonora, Mexico

Catclaw mimosa (Mimosa laxiflora) is a native, perennial half-size brush, which invades short grass prairie and competes with desirable species for water, nutrients and light interferes with cattle grazing and reduces range productivity. Tebuthiuron [1-(5-tert-Butyl-1,3,4-thiadiazol-2-yl)-1,3-dimethylurea; chemical formula C9H16N4OS] is a granular herbicide used to control invasive shrubby species on rangelands with sustainable forage responses (McGinty et al., 2009). Research trials conducted in the Chihuahuan and Sonoran deserts show that tebuthiuron at rates of 0.5 to 1.5 kg a.i./ha effectively controlled most shrubby species and significant increase forage in the Matorral area in Mexico and USA. Local information regarding catclaw mimosa control and forage production increases sustain after bush control in the short grass prairies does not exist. This study was conducted to evaluate vegetation changes after the application of tebuthiuron at rates of 0 and 1.5 kg a.i./ha to control high infestations of catclaw mimosa in the short grass prairies

The challenge of a joint cartography of the Pyrenean landscapes: Hautes-Pyrénées and Aragon

Con la presente investigación se está trabajando por alcanzar uno de los retos pendientes del Pirineo: una cartografía conjunta de paisajes fronterizos que facilite el conocimiento, la coordinación, la gestión y la planificación de los aspectos relacionados con el paisaje a ambos lados de la frontera. La zona de estudio es el Pirineo central en su sector fronterizo de Aragón y las regiones francesas de Nouvelle-Aquitaine y Occitanie. En una primera fase se ha recopilado y revisado la información tanto digital como analógica relativa al paisaje, así como las bases cartográficas disponibles de toda la zona de estudio. A escala de grandes dominios de paisaje en Aragón se cuenta con cartografía de todo el territorio mientras que en Francia se cuenta únicamente con cartografía del Departamento de Ariège que no es fronterizo con Aragón, pero si es paisaje pirenaico. Ello ha permitido contrastar ambas cartografías y elaborar una leyenda común que facilite la interpretación conjunta de ambas cartografías. La aportación de esta investigación ha consistido en elaborar un mapa del pirineo franco-español fronterizo con Aragón sobre la base topográfica del Global Digital Elevation Model y un primer borrador del mapa de dominios de paisaje que abarca todo el territorio aragonés y de Hautes-Pyrénées. Cette recherche vise à atteindre un des enjeux majeurs des Pyrénées: une cartographie des paysages frontaliers qui fournirait l’accés aux connaissances, et faciliterait la coordination, la gestion et la planification du paysage des deux côtés de la frontière. La zone d’étude serait les Pyrénées centrales au niveau de la frontière entre l’Aragon et les régions françaises de Nouvelle-Aquitaine et de l’Occitanie. Dans la première phase, l’information numérique et analogique sur le paysage et les bases cartographiques dans toute la zone d’étude disponible ont été récoltés et examinés. En Aragon la cartographie à l’échelle des grands domaines de paysage est disponible pour l’ensemble du territoire, alors qu’en France la seule cartographie disponible est celle du Département d’Ariège, qui n’est pas frontalier avec l’Aragon mais elle est de paysage pyrénéen. Cela a permis de comparer les deux cartes et développer une légende commune qui facilite l’interprétation conjointe des deux cartes. Cette recherche contribue à développer une carte de la frontière franco-espagnole Pyrénées avec Aragon sur la base topographique Global Digital Elevation Model et d’élaborer un premier projet de la carte des domaines du paysage qui couvre le territoire aragonais et des Hautes-Pyrénées.The main goal of this research is to address one of the open challenges about the Pyrenees: a joint cartography of cross-border landscape that will give access to the knowledge and facilitate the coordination, management, and planning of the different aspects related to the landscape of both sides of the border. The area of study is the central Pyrenees where Aragon and the French region of Nouvelle-Aquitaine and Occitanie are frontier. In the first stage, digital and analogue information about landscape and the available cartographic basis of the whole area of study have been collected and revised. In Aragon, the cartography on the scale of large landscape domains is available for the whole territory, whereas in France the only available mapping is the one from the Department of Ariège, which is not frontier with Aragon but is Pyrenean landscape. This has allowed to contrast the two cartographies and to elaborate a common legend that facilitates the joint interpretation of both mappings. This research contributes to the production of a map of the French-Spanish Pyrenees (around Aragon and its frontier counterpart) using the topographic basis of the Global Digital Elevation Model, and to the elaboration of a preliminary map of the landscape domains covering the entire territory of Aragon and Hautes-Pyrénées