The crucial role of molecular emissions on LIBS differentiation of organic compounds of interest in astrobiology under a Mars simulated atmosphere

In this work, the influence of Martian atmosphere on the recombination mechanisms in laser-induced plasmas of organic compounds of interest in astrobiology has been closely examined. The proposed LIBS methodology reveals new insights concerning the influence of the surrounding atmosphere on the molecular emission of organics. The presence of nitrogen, even in the short concentration found in the low-pressure Mars environment, influences the plasma chemistry and the formation pathways leading to molecular species. Characteristic atomic and molecular emitters (C, H, C2, CN, NH, OH and CH) were inspected in a set of selected organic compounds considered as meaningful biomarkers. For comparative purposes, LIBS analysis was performed in both low-pressure air and Martian atmospheres. Statistical analysis (linear discriminant analysis; DFA) suggested that satisfactory differentiation among materials was feasible under Martian conditions when molecular emissions are computed in the classification algorithm. Atomic lines (C, H) only contribute a mere ~62% to the discriminating analysis, whereas the percentage of successful discrimination was considerably increased (up to 99%) by the progressive introduction of signals associated to molecular bands into the DFA analysis, thus confirming the major contribution of molecular information to the final sorting performance and the feasibility of discriminating closely related organic compounds by LIBS in the Martian atmosphere.his work was partially supported by Programa Operativo FEDER Andalucía 2014–2020, Consejería de Economía y Conocimiento de la Junta de Andalucía, Reference UMA18-FEDERJA-272 and by Project PID2020-119185GB-I00 from Ministerio de Ciencia e Innovación, Spain. The authors would also like to acknowledge the support of the SIGUE-Mars Research Network, the International Space Science Institute (ISSI) Bern and the International Space Science Institute (ISSI) Beijing. // Funding for open access charge: Universidad de Málaga / CBU

Molecular identification of the transient species mediating the deactivation dynamics of solvated guanosine and deazaguanosine

Small structural alterations of the purine/pyrimidine core have been related to important photophysical changes, such as the loss of photostability. Similarly to canonical nucleobases, solute-solvent interactions can lead to a change in the excited state lifetimes and/or to the interplay of different states in the photophysics of these modified nucleobases. To shed light on both effects, we here report a complete picture of the absorption spectra and excited state deactivation of deoxyguanosine and its closely related derivative, deoxydeazaguanosine, in water and methanol through the mapping of the excited state potential energy surfaces and molecular dynamics simulations at the TD-DFT level of theory. We show that the N by CH exchange in the imidazole ring of deoxyguanosine translates into a small red-shift of the bright states and slightly faster dynamics. In contrast, changing solvent from water to methanol implies the opposite, i.e., that the deactivation of both systems to the ground state is significantly hindered

¿Existen diferencias en el comportamiento omnicanal? Análisis webrooming y showrooming

Este trabajo evalúa la influencia que las rutas de procesamiento de la información tienen en el comportamiento webrooming y showrooming. Para ello, se utilizó la base de datos “Observatorio de e-Commerce 2014” de la Consultora GfK que contiene información detallada sobre el proceso de compra de 4.067 consumidores que han adquirido productos de diferentes sectores de la distribución comercial. Los resultados obtenidos utilizando el modelo logit binomial muestran que los consumidores webroomers tienen una conducta más planificada y valoran en mayor medida los criterios de decisión de compra vinculados al producto. Por su parte, los showroomers son compradores más influenciables y valoran más los criterios de decisión vinculados con el distribuidor.This paper evaluates the influence that routes information processing has on the webrooming and showrooming. The empirical research is based on the database compiled by GfK. This database contains detailed information about the buying process of 4,067 consumers who have purchased products from different retail sectors. The results derived from the application of a binomial logit model show that webroomers have a planned behavior and assess further the purchasing decision criteria linked to the product. Meanwhile, the showroomers are more impressionable and more valued decision criteria linked to the distributor

¿Son clasificados correctamente los pacientes con dolor crónico y fibromialgia por las escalas e índices de validez del MMPI-2?

A study was designed to find out whether MMPI-2 validity scales and indexes differentiate between true fibromyalgia sufferers, patients with chronic organic pain and normal people, as well as whether they are correctly classified. 105 subjects participated in the study, 27 diagnosed with fibromyalgia and 44 with chronic organic pain and 34 were healthy people, who answered the MMPI-2 following standard instructions. The results showed that fibromyalgia patients scored higher than the control group in the F, Fb, F-K, Fp, Ds, and FBS scales and indexes and that patients with chronic organic pain scored higher in the Ds and FBS scales than the control group. The case study revealed that the F, Fb, F-K, Fp, Ds, and FBS scales and indexes over-diagnose malingering in patients with fibromyalgia, both in comparison with the clinical population and with the normative group. Likewise, patients with chronic organic pain were overdiagnosed as malingerers by all the scales and indexes in comparison with the normative population and by the Fp and FBS scales in comparison with the clinical population. In addition, it was found that at least one of the scales for measuring defensiveness –L, Wsd and Mp– classified 79.5% of the truly ill patients as faking good. The implications for clinical and forensic practice are discussed, as well as for the definition of decision criteria and the (re)classification as true negatives of genuine cases classified as malingerers by the malingering measuring scales and indexesSe diseñó un estudio con el objetivo de conocer si escalas e índices de validez del MMPI-2 diferencian entre verdaderos enfermos de fibromialgia, pacientes con dolor crónico de etiología orgánica y personas normales, así como si los clasifican correctamente. Participaron en el estudio 105 sujetos, 27 diagnosticados de fibromialgia, 44 de dolor crónico con etiología orgánica y 34 sanos, que respondieron al MMPI-2 bajo las instrucciones estándar. Los resultados mostraron que los pacientes de fibromialgia puntuaban más alto en las escalas e índices F, Fb, F-K, Fp, Ds y FBS que el grupo control y los pacientes de dolor crónico con etiología orgánica en las escalas Ds y FBS. El estudio de casos evidenció que las escalas e índices F, Fb, F-K, Fp, Ds y FBS sobrediagnostican simulación en los pacientes con fibromialgia, tanto en comparación con la población clínica como con la normativa. Asimismo, los pacientes con dolor crónico con etiología orgánica fueron sobrediagnosticados como simuladores por todas las escalas e índices en comparación con la población normativa y por las escalas Fp y FBS en comparación con la población clínica. Además hallamos que al menos una de las escalas de medida de defensividad –L, Wsd y Mp– clasificaba como disimuladores al 79.5% de los verdaderos enfermos. Se discuten las implicaciones para la práctica clínica y forense, así como para la definición de criterios de decisión y la (re)clasificación como verdaderos negativos de aquellos casos genuinos clasificados como simuladores por las escalas e índices de medida de la simulaciónS

Influencia en los estilos de aprendizaje en estudiantes de primer año de licenciatura en una universidad pública.

La presente investigación tuvo como propósito analizar los diferentes estilos de aprendizaje de los estudiantes que estaban cursando el primer año de la carrera en una universidad pública de México. Para identificar los estilos de aprendizaje de los estudiantes fue utilizado el cuestionario Honey- Alonso de Estudios de Aprendizaje (CHAEA). El tipo de estudio que fue realizado es de tipo no experimental, ex post facto (Gall, Borg and Gall, 1996; Kerlinger y Howard, 2002). En el periodo académico de agosto del 2012 a junio del 2013. Los datos se obtuvieron del cuestionario aplicado a 1,272 estudiantes de 3 facultades, F1, F2 y F3 y fueron analizados a través del paquete SPPS versión 21, utilizando estadística descriptiva. Los resultados indican que predomina el estilo de aprendizaje reflexivo en los estudiantes de las 3 facultades con preferencia moderada según el Baremo General de Preferencia en Estilos de Aprendizaje (Alonso, Gallego y Honey, 2007), seguido por el pragmático, el teórico y por último se encuentra el activo

Optimization procedure of source/sink converters for DC power distribution nano-grids

2018 IEEE 19th Workshop on Control and Modeling for Power Electronics (COMPEL), 25-28 junio, Padua (Italia)DC-Power Distribution Systems require DC-DC converters to interface all their elements. These converters should provide a high power quality and be efficient, compact and inexpensive. Furthermore, the characteristics of the loads and sources connected to these converters are not known beforehand and may change widely (there is no regulation about the DC loads, such as IEC61000-3-2 in AC grids). As a consequence, the design procedure is neither standard nor obvious. This work proposes an optimized design procedure for any Bus Provider in a DC-Power Distribution System. It is based on models, hence extensible to different Bus-Provider topologies, and takes into account the main issues in DC-Power Distribution Systems, especially the design conditions imposed by the wide variety of loads, or even sources, which may be connected to the output bus. Experimental results obtained from three designs show a close match with the analytical models and verify that the proposed procedure minimizes converter losses and complies with the requirement

A very simple analog control for QSW-ZVS source/sink buck converter with seamless mode transition

2018 IEEE 19th Workshop on Control and Modeling for Power Electronics (COMPEL), 25-28 junio, Padua (Italia)A simple, analog, control circuit is proposed for seamless transition between source and sink modes in a Quasi- Square-Wave Zero Voltage Switching (QSW-ZVS) source/sink buck converter. The inductor current is controlled by a variablewidth hysteretic current mode control. The upper and lower bounds of the hysteretic band are clamped to ensure QSWZVS operation with a single current command from the control loop and independently from the power flow direction. This enables the control of any PWM converter able to operate in QSW-ZVS with a single control loop. If the proposed circuit is used, using a complex multi-mode or look-up-table based digital control is no longer required, simplifying the implementation and lowering the cost of the converter. A 50 W buck converter is built to demonstrate the proposed control circuit and experimental measurements are shown to verify its correct operatio

Detection of indigenous organic matter in rocks from the interpretation of carbon molecular forms in the laser-induced plasma.

Oil shale, a sedimentary rock containing organic matter and a variety of inorganic minerals including carbonates and kerogens, serves as a significant source of organic material on Earth [1]. Kerogen, the most abundant form of organic matter, differs in chemical composition based on the microorganisms that contributed to its formation [2]. Laser-induced breakdown spectroscopy (LIBS) is a powerful analytical technique used on the Mars rover, allowing elemental characterization of Martian rocks, soils, and sediments. This study presents the first-ever detection of natural organic matter in oil shale using LIBS under simulated Martian conditions. Through an analysis of emitting species including CN and C2, LIBS successfully identifies the presence of organic compounds in this sedimentary rock. The ability to detect and characterize natural organic matter in oil shale, known for its potential to suggest the existence of ancient life, holds significant relevance in astrobiology. Furthermore, this information contributes to the identification of biosignatures and aids in the development of planetary exploration strategies. Oil shale samples were analyzed using LIBS under simulated Martian conditions after being crushed, pressed into pellets, and subjected to pyrolysis to remove organic matter. The analysis revealed significant changes in the infrared spectra, confirming the absence of aliphatic hydrocarbons after pyrolysis [3]. The LIBS results demonstrated the presence of molecular species associated with hydrocarbons, such as CN and C2, through distinct spectral emissions. The absence of these emissions in the pyrolyzed sample further supported the detection of organic matter originating from kerogen.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Estimating the Relationship between Reading in Primary Education, Educational Attainment and Social Welfare. The Case of Extremadura (Spain)

The purpose of this paper is to analyse the relationship between the Social Welfare Index and the reading habits of primary school students in Extremadura (Spain). A study has been performed which consists of two parts. First, we conducted 4,288 surveys on reading habits in 87 municipalities. Second, we calculated the social welfare index. The statistical analysis refl ects two conclusions: firstly, educational and socio-economic policies have resulted in equal opportunities that allow for similar social possibilities throughout the territory; secondly, Educational Attainment of parents is the most decisive factor in obtaining the best results in terms of students' reading habits

Las nuevas tecnologías en la respuesta educativa a la diversidad : actas del II Congreso Nacional de Nuevas Tecnologías y Necesidades Educativas Especiales (Tecnonet 2002), Murcia (España), 19, 20 y 21 de septiembre de 2002

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