Orientational transitions in a nematic confined by competing surfaces

The effect of confinement on the orientational structure of a nematic liquid crystal model has been investigated by using a version of density-functional theory (DFT). We have focused on the case of a nematic confined by opposing flat surfaces, in slab geometry (slit pore), which favor planar molecular alignment (parallel to the surface) and homeotropic alignment (perpendicular to the surface), respectively. The spatial dependence of the tilt angle of the director with respect to the surface normal has been studied, as well as the tensorial order parameter describing the molecular order around the director. For a pore of given width, we find that, for weak surface fields, the alignment of the nematic director is perpendicular to the surface in a region next to the surface favoring homeotropic alignment, and parallel along the rest of the pore, with a interface separating these regions (S phase). For strong surface fields, the director is distorted uniformly, the tilt angle exhibiting a linear dependence with the distance normal to the surface (L phase). Our calculations reveal the existence of a first-order transition between the two director configurations, which is driven by changes in the surface field strength, and also by changes in the pore width. In the latter case the transition occurs, for a given surface field, between the S phase for narrow pores and the L phase for wider pores. A link between the L-S transition and the anchoring transition observed for the semi-infinite case is proposed. We also provide calculations with a phenomenological approach that yields the same main result that DFT in the scale length where this is valid.Comment: submitted to PR

Adsorption of antipyrine by activated carbons from FeCl3-activation of Tara gum

Activated carbons were synthesized by FeCl3-activation of Tara gum at different temperatures (400–1000 °C). The activating agent and the precursor were physically mixed at different ratios (r= FeCl3:precursor, 0.5–3.0 wt). At r=2 and 800 °C the most developed porosity was achieved, with a BET surface area of 1680 m2·g-1 and a pore volume near 1 cm3·g-1, corresponding mostly to micropores (˜75%). The carbons were fully characterized and tested for the aqueous-phase adsorption of antipyrine, used as model emerging pollutant. The kinetic curves and adsorption isotherms at 20, 40 and 60 °C were obtained, which fitted well to hyperbolic and Langmuir equations, respectively. At 20 °C, the saturation adsorption capacity was around 275 mg·g-1 AC. The free energy of adsorption varied from -40.2 to -35.7 kJ·mol-1, while values close to -3 kJ·mol-1 and 112 J·mol-1·K-1, were obtained for the enthalpy and entropy of adsorption, respectively

Modeling diameter distributions with six probability density functions in Pinus halepensis Mill. Plantations using low-density airborne laser scanning data in Aragón (northeast Spain)

Producción CientíficaThe diameter distributions of trees in 50 temporary sample plots (TSPs) established in Pinus halepensis Mill. stands were recovered from LiDAR metrics by using six probability density functions (PDFs): the Weibull (2P and 3P), Johnson’s SB, beta, generalized beta and gamma-2P functions. The parameters were recovered from the first and the second moments of the distributions (mean and variance, respectively) by using parameter recovery models (PRM). Linear models were used to predict both moments from LiDAR data. In recovering the functions, the location parameters of the distributions were predetermined as the minimum diameter inventoried, and scale parameters were established as the maximum diameters predicted from LiDAR metrics. The Kolmogorov–Smirnov (KS) statistic (Dn), number of acceptances by the KS test, the Cramér von Misses (W2) statistic, bias and mean square error (MSE) were used to evaluate the goodness of fits. The fits for the six recovered functions were compared with the fits to all measured data from 58 TSPs (LiDAR metrics could only be extracted from 50 of the plots). In the fitting phase, the location parameters were fixed at a suitable value determined according to the forestry literature (0.75·dmin). The linear models used to recover the two moments of the distributions and the maximum diameters determined from LiDAR data were accurate, with R2 values of 0.750, 0.724 and 0.873 for dg, dmed and dmax. Reasonable results were obtained with all six recovered functions. The goodness-of-fit statistics indicated that the beta function was the most accurate, followed by the generalized beta function. The Weibull-3P function provided the poorest fits and the Weibull-2P and Johnson’s SB also yielded poor fits to the data.Ministerio de Economía, Industria y Competitividad, Ayudas Torres Quevedo- (grant PTQ-16-08445)Fondo Europeo Agrario de Desarrollo Rural (FEADER) Programa de Desarrollo Rural de Aragón 2014-2020 - (project RF-64079

Androgen receptor gene polymorphism influence fat accumulation: a longitudinal study from adolescence to adult age.

To determine the influence of androgen receptor CAG and GGN repeat polymorphisms on fat mass and maximal fat oxidation (MFO), CAG and GGN repeat lengths were measured in 128 young boys, from which longitudinal data were obtained in 45 of them [mean?±?SD: 12.8?±?3.6 years old at recruitment, and 27.0?±?4.8 years old at adult age]. Subjects were grouped as CAG short (CAGS ) if harboring repeat lengths ?21, the rest as CAG long (CAGL ); and GGN short (GGNS ) if GGN repeat lengths ?23, or long if >?23 (GGNL ). CAGS and GGNS were associated with lower adiposity than CAGL or GGNL (P?<?0.05). There was an association between the logarithm of CAG repeats polymorphism and the changes of body mass (r?=?0.34, P?=?0.03). At adult age, CAGS men showed lower accumulation of total body and trunk fat mass, and lower resting metabolic rate (RMR) and MFO per kg of total lean mass compared with CAGL (P?<?0.05). GGNS men also showed lower percentage of body fat (P?<?0.05). In summary, androgen receptor CAG and GGN repeat polymorphisms are associated with RMR, MFO, fat mass, and its regional distribution in healthy male adolescents, influencing fat accumulation from adolescence to adult age

Influencia de las infiltraciones en la rehabilitación energética de la envolvente. El caso del plan de actuaciones en el parque público residencial de Andalucía

The present study presents the research on the energy retrofit of the building envelope of 615 social housing that are part of the sustainable construction plans for the public housing stock of Andalusia (southern Spain). The analysis provides a new assessment of the relationship between the air-tightness and the energy demand for air conditioning of dwellings in warm climate. Both magnitudes offer a parallelism in the results, with average values of 21.45% decrease in air changes rate and 21.82% decrease in demand. To this end, during the implementation of interventions, tests of infiltrations have been developed in dwellings. The measured air permeability are used as input in a process of energy modeling under different approaches, differentiating the controlled air leakages (ventilation) and the uncontrolled or unnecessary ones (infiltration). The results show the behavior of buildings after refurbishment and energy savings by air leakage can be quantified in each case.El presente estudio presenta la investigación sobre la rehabilitación energética de la envolvente en una muestra de 615 viviendas sociales, incluidas dentro de los planes de construcción sostenible para el parque público residencial de Andalucía. Se evalúa de forma novedosa la relación entre las tasas de renovación de aire exterior y la demanda de climatización de viviendas en clima cálido. Ambas magnitudes ofrecen un paralelismo en los resultados, con valores promedio de 21,45% de disminución de tasa de renovación y un 21,82% de disminución en la demanda. Para ello, durante la ejecución de las intervenciones se ha desarrollado un muestreo de infiltraciones en viviendas. Las permeabilidades medidas se utilizan como parámetros de entrada en un proceso de modelizaciones energéticas bajo diferentes hipótesis, diferenciando la entrada de aire controlada o necesaria (ventilación) y la incontrolada o innecesaria (infiltraciones). Los resultados permiten visualizar el comportamiento de los edificios rehabilitados, cuantificando el ahorro energético como consecuencia de las infiltraciones para cada caso

Measurement of the scintillation resolution in liquid xenon and its impact for future segmented calorimeters

We report on a new measurement of the energy resolution that can be attained in liquid xenon when recording only the scintillation light. Our setup is optimised to maximise light collection, and uses state-of-the-art, high-PDE, VUV-sensitive silicon photomultipliers. We find a value of 2.7% +- 0.3% FWHM at 511 keV, a result much better than previous measurements and very close to the Poissonian resolution that we expect in our setup (3.0% +- 0.7% FWHM at 511 keV). Our results are compatible with a null value of the intrinsic energy resolution in xenon, with an upper bound of 1.5% FWHM at 95% CL at 511 keV, to be compared with 3--4% FWHM in the same region found by theoretical estimations which have been standing for the last twenty years. Our work opens new possibilities for apparatus based on liquid xenon and using scintillation only. In particular it suggests that modular scintillation detectors using liquid xenon can be very competitive as building blocks in segmented calorimeters, with applications to nuclear and particle physics as well as Positron Emission Tomography technology

Greater basal skeletal muscle AMPKalpha phosphorylation in men than in women: associations with anaerobic performance

This study was designed to investigate the association of gender, fibre type composition, and anaerobic performance with the basal skeletal muscle signalling cascades regulating muscle phenotype

TiO2:Cex onto Al Clays for Photocatalytic Solar Water Disinfection

A novel methodology was employed to prepare new nanocomposites with photocatalytic properties based on Ce-doped TiO2 nanoparticles arranged over a layered silicate. The catalysts were porous materials formed by exfoliated silicate layers surrounded by anatase nanoparticles. In this way, the anatase was doped by different amounts of Ce, yielding to catalysts with light absorption properties on the visible region. The photocatalytic behavior was tested for different reactions: adsorption and photocatalysis, showing outstanding and promising results for the removal of bacteria by using solar light as an energy source. The influence of the physicochemical properties of the catalyst and the reaction parameters will be studied in detail to manage new catalysts for the disinfection of drinking water

Evaluation of the GEXCAT software in the design and correction of multiple choice exams: preliminary data

Resúmenes IV Congreso VetDoc de Docencia Veterinaria, León 2017 (6-7 de Julio)[ES] El sistema de evaluación continua propuesto por el Plan Bolonia supone un incremento de la carga de trabajo del profesor universitario (Pagani y González, 2002). Los exámenes tipo test son una opción, sobre todo en el caso de asignaturas con un elevado número de créditos. Permiten una pronta corrección y se puede aumentar el número de evaluaciones, mejorando los resultados de los alumnos, lo que aumenta su motivación (Escolano et al., 2014). Para que los alumnos no se copien convienen preparar varios modelos de exámenes, aunque esto complica la corrección, facilitando el error humano. Para evitar tal situación se han creado programas informáticos. El programa privativo de Gestión de Exámenes y Corrección Automática de Tests, GEXCAT (Innocan, 2017), es una herramienta que ayuda en la preparación y corrección de exámenes tipo test, con la ventaja de utilizar hojas DINA4 y un escáner básico. Permite generar exámenes de tipo test tanto en formato electrónico como en papel. Barajando tanto las preguntas como las respuestas puede llegar a generar hasta nueve modelos de examen. Además, las preguntas pueden ser clasificadas por nivel de dificultad. El programa proporciona las correcciones casi instantáneamente, pudiendo exportar las calificaciones en formato Excel, enviar los resultados a los alumnos vía email y gestionar eficazmente las evaluaciones continuas

Monte Carlo characterization of PETALO, a full-body liquid xenon-based PET detector

[EN] New detector approaches in Positron Emission Tomography imaging will play an important role in reducing costs, lowering administered radiation doses, and improving overall performance. PETALO employs liquid xenon as the active scintillating medium and UV-sensitive silicon photomultipliers for scintillation readout. The scintillation time in liquid xenon is fast enough to register time-of-flight information for each detected coincidence, and sufficient scintillation is produced with low enough fluctuations to obtain good energy resolution. The present simulation study examines a full-body-sized PETALO detector and evaluates its potential performance in PET image reconstruction.This work was supported by the European Research Council under grant ID 757829 and by Ministerio de Economia y Competitividad for grant FPA2016-78595-C3-1-R.Renner, J.; Romo-Luque, C.; Aliaga, RJ.; Álvarez-Puerta, V.; Ballester Merelo, FJ.; Benlloch-Rodríguez, J.; Carrión, J.... (2022). Monte Carlo characterization of PETALO, a full-body liquid xenon-based PET detector. Journal of Instrumentation. 17(5):1-14. https://doi.org/10.1088/1748-0221/17/05/P0504411417