212 research outputs found
Study of drone charging system in isolated environments
[ES] Estudio y diseño de solución propuesta para recarga de drones mediante WPT en entornos aislados en los cuales no se disponga de posibilidad de conexión a la red eléctrica. Esta solución se concibe como base de operaciones de UAVs para el control y protección del terreno ante desastres medioambientales, así como otros propósitos como la parametrización y registro de campos de cultivo. Debido a la concepción de esta como herramienta en múltiples ámbitos y como una solución para diferentes emplazamientos, así como diferentes UAVs se busca que el diseño sea modular y de fácil adaptabilidad para estos diferentes requerimientos. A su vez debido a la instalación de este sistema en entornos aislados se busca en el planteamiento de esta opción la minimización del mantenimiento necesario, y un proceso de puesta a punto sencillo. Por lo cual, se establece como requisito el empleo del mínimo número de elementos móviles. Para poder llevar a cabo este concepto, se propone como solución una estructura modular con una instalación fotovoltaica aislada de red en conexión con un sistema de recarga WPT que controla y protege la recarga de los dispositivos. Como ejemplo de modularidad se presentan tres posibles alternativas de configuración del sistema estructural adaptando el número de módulos implementados en cada una de ellas. Los diseños de estas estructuras han sido desarrollados y comprobados a través del software Solidworks y de su correspondiente complemento Solidworks Simulation. Como ejemplo de aplicación e instalación de esta estructura se realiza un dimensionado de equipamientos siguiendo la normativa en instalaciones aisladas de red vigente en España, tomando como referencia las condiciones climáticas del emplazamiento propuesto como ejemplo situado en un terreno rústico en Posada de Valdeón, León. El conjunto de los datos de irradiación y análisis de la instalación fotovoltaica han podido ser interpretados mediante el análisis de los datos obtenidos a través de PVGIS[EN] Study and design of a proposed solution for recharging drones through WPT in isolated environments in which there is no possibility of connecting to the electrical network. This solution is conceived as a base of operations for UAVs for the control and protection of the land against environmental disasters, as well as other purposes such as the parameterization and registration of crop fields. Due to the conception of this as a tool in multiple areas and as a solution for different locations, as well as different UAVs, the design is intended to be modular and easily adaptable to these different requirements. In turn, due to the installation of this system in isolated environments, the approach of this option seeks to minimize the necessary maintenance, and a simple set-up process. Therefore, the use of the minimum number of mobile elements is established as a requirement. In order to carry out this concept, a modular structure with a photovoltaic installation isolated from the network in connection with a WPT recharging system that controls and protects the recharging of the devices is proposed as a solution. As an example of modularity, three possible configuration alternatives of the structural system are presented, adapting the number of modules implemented in each of them. The designs of these structures have been developed and tested using Solidworks software and its corresponding Solidworks Simulation add-on. As an example of the application and installation of this structure, a dimensioning of equipment is carried out following the regulations on isolated installations from the current network in Spain, taking as a reference the climatic conditions of the proposed site as an example located on a rustic plot of land in Posada de Valdeón, León. The set of irradiation data and analysis of the photovoltaic installation have been interpreted by analyzing the data obtained through PVGIS
The Evolution of Luminous Compact Blue Galaxies: Disks or Spheroids?
Luminous compact blue galaxies (LCBGs) are a diverse class of galaxies
characterized by high luminosity, blue color, and high surface brightness that
sit at the critical juncture of galaxies evolving from the blue to the red
sequence. As part of our multi-wavelength survey of local LCBGs, we have been
studying the HI content of these galaxies using both single-dish telescopes and
interferometers. Our goals are to determine if single-dish HI observations
represent a true measure of the dynamical mass of LCBGs and to look for
signatures of recent interactions that may be triggering star formation in
LCBGs. Our data show that while some LCBGs are undergoing interactions, many
appear isolated. While all LCBGs contain HI and show signatures of rotation,
the population does not lie on the Tully-Fisher relation nor can it evolve onto
it. Furthermore, the HI maps of many LCBGs show signatures of dynamically hot
components, suggesting that we are seeing the formation of a thick disk or
spheroid in at least some LCBGs. There is good agreement between the HI and
H-alpha kinematics for LCBGs, and both are similar in appearance to the H-alpha
kinematics of high redshift star-forming galaxies. Our combined data suggest
that star formation in LCBGs is primarily quenched by virial heating,
consistent with model predictions.Comment: 4 pages, 2 figures, to appear in the proceedings of IAU Symposium
277, "Tracing the Ancestry of Galaxies on the Land of our Ancestors", eds. C.
Carignan, K.C. Freeman, and F. Combe
Lifestyle and Sociodemographic Parameters Associated with Mental and Physical Health during COVID-19 Confinement in Three Ibero-American Countries. A Cross-Sectional Pilot Study
[EN] Background: The aim of the present study was to determine the association between the health-related quality of life (HRQoL) with sociodemographic parameters and lifestyle during COVID-19 confinement in Mexico, Chile, and Spain. Methods: A cross-sectional pilot study, with 742 observations of online surveys in 422, 190, and 130 individuals from Mexico, Chile, and Spain, respectively. Sociodemographic data, presence of comorbidities, food habits, and physical activity (PA) patterns were evaluated. The HRQoL was evaluated according to the SF-36 Health Survey. The multilinear regression analysis was developed to determine the association of variables with HRQoL and its physical and mental health dimensions. Results: The female sex in the three countries reported negative association with HRQoL (Mexico: �����4.45, p = 0.004; Chile: �����8.48, p < 0.001; Spain: �����6.22, p = 0.009). Similarly, bad eating habits were associated negatively with HRQoL (Mexico: �����6.64, p < 0.001; Chile: �����6.66, p = 0.005; Spain: 5.8, p = 0.032). In Mexico, PA limitations presented a negative association with HRQoL ( 4.71, p = 0.011). In Chile, a sedentary lifestyle (h/day) was linked negatively with HRQoL ( 0.64, p = 0.005). In Spain, the highest associations with HRQoL were the presence of comorbidity ( 11.03, p < 0.001) and smoking ( 6.72, p = 0.02). Moreover, the PA limitation in Mexico ( 5.67, p = 0.023) and Chile ( 9.26, p = 0.035) was linked negatively with mental health. Conclusions: The bad eating habits, PA limitations, female sex, comorbidity presence, and smoking were parameters linked negatively with HRQoLS
Prevalencia estacionaria de sobrepeso y obesidad en universitarios del sur de Veracruz, México
Objetivo: Determinar la prevalencia de sobrepeso y obesidad al ingreso a la universidad y su relación con factores sociodemográficos en estudiantes. Material y métodos: El estudio incluyó a 5 071 estudiantes a los que se realizó antropometría, se determinó colesterol total y se les solicitó información sociodemográfica. Los grupos de estudiantes se muestrearon al comienzo del año escolar a partir de 2001 y hasta 2005. Resultados: La ocurrencia de sobrepeso y obesidad fue de 21.3% y 8.3% respectivamente. No hubo diferencias entre las prevalencias anuales o quinquenal. Doce por ciento presentó hipercolesterolemia. Ser varón, urbano e hipercolesterolémico se vinculó significativamente con sobrepeso y obesidad (p < 0.001). Conclusiones: La prevalencia de sobrepeso y obesidad se ha mantenido, lo que difiere de lo informado a nivel internacional y el factor sociodemográfico que más se asoció a la obesidad, fue el de vivir en la ciudad y ser hombre
Extreme Saharan dust event over the southern Iberian Peninsula in september 2007: active and passive remote sensing from surface and satellite
This study investigates aerosol optical properties during the extreme Saharan dust event detected from 3 to 7 September 2007 over Granada, southern Iberian Peninsula, with both active and passive remote sensing instrumentation from surface and satellite. The intensity of the event was visualized on the aerosol optical depth series obtained by the sun-photometer Cimel CE 318-4 operated at Granada in the framework of AERONET from August 2004 until December 2008 (level 2 data). A combination of large aerosol optical depth (0.86–1.50) at 500 nm, and reduced Angström exponent (0.1–0.25) in the range 440–870 nm, was detected on 6 September during daytime. This Saharan dust event also affected other Iberian Peninsula stations included in AERONET (El Arenosillo and Évora stations), and it was monitored by MODIS instrument on board Aqua satellite. Vertically resolved measurements were performed by a ground-based Raman Lidar and by CALIPSO satellite. During the most intense stage, on 6 September, maximum aerosol backscatter values were a factor of 8 higher than other maxima during this Saharan dust event. Values up to 1.5×10−2 km−1 sr−1 at 355 and 532 nm were detected in the layer with the greatest aerosol load between 3–4 km a.s.l., although aerosol particles were also detected up to 5.5 km a.s.l. In this stage of the event, dust particles at these altitudes showed a backscatter-related Angström exponent between –0.44 and 0.53 for the two spectral intervals considered. The results from different measurements (active/passive and ground-based/satellite) reveal the importance of performing multi-instrumental measurements to properly characterize the contribution of different aerosol types from different sources during extreme events. The atmospheric stabilization effect of the aerosol particles has been characterized by computing the solar heating rates using SBDART code.This work is supported by the Spanish
Ministry of Education project CGL2007-66477-C02-01 and
CSD2007-00067, by Andalusian Regional Government projects
P06-RNM-01503 and P08-RNM-3568, and by the EARLINETASOS
project (EU Coordination Action, contract No. 025991
(RICA))
Multiplier ideals of plane curve singularities via Newton polygons
We give an effective method to determine the multiplier ideals and jumping numbers associated with a curve singularity C in a smooth surface.
We characterize the multiplier ideals in terms of certain Newton polygons, generalizing a theorem of Howald, which holds when C is Newton non-degenerate with respect to some local coordinate system. The method uses toroidal embedded resolutions and generating sequences of families of valuations, and can be extended to some classes of higher dimensional hypersurface singularities
A sustainable methodology to produce open-cell porous membranes with control on the dense layer thickness
Producción CientíficaA new approach to produce porous membranes with dense or porous top layer is proposed in this work by employing a solvent-free method. PMMA/MAM formulations were selected as a base material in order to create open-cell or close-cell structures by gas dissolution foaming employing CO2 as a blowing agent. Furthermore, by introducing the gas diffusion barrier approach to CO2 dissolution foaming, it is possible to control the thickness of the dense layer in both edges, obtaining defect-free membranes (i.e., completely dense without pin-holes). The effectiveness of nanocellular polymers as gas separation membranes was evaluated. In this way, the permeability, selectivity, and permeance were correlated to the cellular structure (open or close-cell) as well as to the dense layer thickness. Furthermore, the effective thickness of the selective layer has been calculated from gas permeability measurements, obtaining an accurate control of that parameter from the tunable cellular structure. Therefore, membranes composed of desired selective layer and a porous structure as a mechanical support are produced by a solvent-free methodology.Ministerio de Ciencia e Innovación (PRE2019-088820)EU NextGenerationEU/ PRTR program (PLEC2021-007705)FEDER (UE) (RTI2018 - 098749-B-I00, RTI2018 - 097367-A-I00, PID2021-127108OB-I00, PID2019-109403RB-C21/AEI/10.13039/501100011033, TED2021-13 0965B-I00 y PDC2022-133391- I00)Junta de Castilla y León and EU-FEDER program (CLU-2019-04 and VA202P20
Word-Length Correlations and Memory in Large Texts: A Visibility Network Analysis
We study the correlation properties of word lengths in large texts from 30 ebooks in the English language from the Gutenberg Project (www.gutenberg.org) using the natural visibility graph method (NVG). NVG converts a time series into a graph and then analyzes its graph properties. First, the original sequence of words is transformed into a sequence of values containing the length of each word, and then, it is integrated. Next, we apply the NVG to the integrated word-length series and construct the network. We show that the degree distribution of that network follows a power law, P(k)∼k−γP(k)∼k-γ, with two regimes, which are characterized by the exponents γs≈1.7γs≈1.7 (at short degree scales) and γl≈1.3γl≈1.3 (at large degree scales). This suggests that word lengths are much more strongly correlated at large distances between words than at short distances between words. That finding is also supported by the detrended fluctuation analysis (DFA) and recurrence time distribution. These results provide new information about the universal characteristics of the structure of written texts beyond that given by word frequencies
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