349 research outputs found
Psychological elements explaining the consumer's adoption and use of a website recommendation system: A theoretical framework proposal
The purpose of this paper is to understand, with an emphasis on the psychological perspective of the research problem, the consumer's adoption and use of a certain web site recommendation system as well as the main psychological outcomes involved. The approach takes the form of theoretical modelling. Findings: A conceptual model is proposed and discussed. A total of 20 research propositions are theoretically analyzed and justified. Research limitations/implications: The theoretical discussion developed here is not empirically validated. This represents an opportunity for future research. Practical implications: The ideas extracted from the discussion of the conceptual model should be a help for recommendation systems designers and web site managers, so that they may be more aware, when working with such systems, of the psychological process consumers undergo when interacting with them. In this regard, numerous practical reflections and suggestions are presented
Deep learning for the modeling and inverse design of radiative heat transfer
Deep learning is having a tremendous impact in many areas of computer science and engineering. Motivated by this success, deep neural networks are attracting increasing attention in many other disciplines,
including the physical sciences. In this work, we show that artificial neural networks can be successfully used in the theoretical modeling and analysis of a variety of radiative-heat-transfer phenomena and
devices. By using a set of custom-designed numerical methods able to efficiently generate the required
training data sets, we demonstrate this approach in the context of three very different problems, namely
(i) near-field radiative heat transfer between multilayer systems that form hyperbolic metamaterials,
(ii) passive radiate cooling in photonic crystal slab structures, and (iii) thermal emission of subwavelength objects. Despite their fundamental differences in nature, in all three cases we show that simple
neural-network architectures trained with data sets of moderate size can be used as fast and accurate
surrogates for doing numerical simulations, as well as engines for solving inverse design and optimization in the context of radiative heat transfer. Overall, our work shows that deep learning and artificial
neural networks provide a valuable and versatile toolkit for advancing the field of thermal radiatio
Tunable Thermal Emission of Subwavelength Silica Ribbons
The thermal properties of individual subwavelength
objects, which defy Planck’s law, are attracting significant
fundamental and applied interest in different research areas.
Special attention has been devoted to anisotropic structures made
of polar dielectrics featuring thicknesses smaller than both the
thermal wavelength and the skin depth. Recently, a novel
experimental technique has enabled the measurement of the
thermal emissivity of anisotropic SiO2 nanoribbons (with
thicknesses on the order of 100 nm), demonstrating that their
emission properties can be largely tuned by adjusting their
dimensions. However, despite the great interest aroused by these
results, their rigorous theoretical analysis has remained elusive due
to the computational challenges arising from the vast difference in
the length scales involved in the problem. In this work, we present a systematic theoretical analysis of the thermal emission
properties of these dielectric nanoribbons based on simulations within the framework of fluctuational electrodynamics carried out
with the boundary element method implemented in the SCUFF-EM code. In agreement with the experiments, we show that the
emissivity of these subwavelength structures can be largely tuned and enhanced over the thin-film limit. We elucidate that the
peculiar emissivity of these nanoribbons is due to the very anisotropic thermal emission that originates from the phonon polaritons
of this material and the properties of the waveguide modes sustained by these dielectric structures. Our work illustrates the rich
thermal properties of subwavelength objects, as well as the need for rigorous theoretical methods that are able to unveil the complex
thermal emission phenomena emerging in this class of systemsJ.J.G.E. was supported by the Spanish Ministry of Science and
Innovation through an FPU grant (FPU19/05281). J.B.A.
acknowledges financial support from the Ministerio de Ciencia,
Innovacioń y Universidades (RTI2018-098452-B-I00). J.C.C.
acknowledges funding from the Spanish Ministry of Science
and Innovation (PID2020-114880GB-I00
A Systematic Review of Augmented Reality in Health Sciences: A Guide to Decision-Making in Higher Education
The objective of this study was to investigate the usability of the augmented reality (AR)
in higher education in the area of health sciences to describe what type of interventions have been
developed, their impact on various psychopedagogical aspects of the students as well as the main
advantages, disadvantages and challenges in incorporating AR in the teaching-learning process. A
systematic review was carried out in the CINAHL, PsycINFO, MEDLINE,Web of Science databases
and the Google Scholar search engine. The search was limited to original research articles written in
English, Spanish or Portuguese since 2014. The quality of the selected articles (n = 19) was assessed
using the Mixed Methods Appraisal Tool (MMAT). The applications and electronic devices used
and the measurement instruments used were described. The use of AR made it easier for students
to acquire skills, especially in courses with a high component of three-dimensional visualization,
and positively influenced various aspects of the learning process such as motivation, satisfaction or
autonomous learning. As an educational technological tool applied to higher education in health
sciences, AR improves the teaching-learning process by influencing it in a multidimensional wayS
A pathogen complex between the root knot nematode Meloidogyne incognita and Fusarium verticillioides results in extreme mortality of the inka nut (Plukenetia volubilis)
The combined infection of the root knot nematode Meloidogyne incognita and two Fusarium species led to high plant mortality of inka nut (Plukenetia volubilis) seedlings in pots after 80 days growth in two independent inoculation experiments. Inoculation of M. incognita juveniles and conidia of F. solani or F. verticillioides, simultaneously, increased plant mortality by 25-30%, compared with M. incognita alone (5-10% mortality). When inoculated with F. verticillioides at 20 days post nematode inoculation, plant mortality increased to 55%. Either of the Fusarium spp. alone caused some plant mortality, but less than when combined with M. incognita. The synergistic interaction of M. incognita and especially F. verticillioides demonstrates a lethal outcome for inka nuts. It appears that M. incognita creates favorable conditions that lead to enhanced effect and damage by the Fusarium species, especially F. verticillioides, leading to devastating levels of plant death
Effectiveness of augmented reality in learning about leg ulcer care: a quasi-experimental study in nursing students
Chronic wounds are a serious public health problem worldwide. Providing optimal treatment to patients suffering from leg ulcers is a priority for nursing. Therefore, nursing students need to acquire the necessary competencies to provide evidence-based care. Augmented Reality (AR) is an emerging technology in health science education which can help nursing students achieve these skills if it is promoted by both institutions and educationalistsS
Asociación talco-fengita en esquistos blancos de la Zona Interna del Rif, Norte de Marruecos
Rodríguez-Ruiz Mª Dolores, Isabel Abad, María J. Bentabol, Carlos Sanz-de-Galdeano (2019) Asociación talco-fengita en esquistos blancos de la Zona Interna del Rif, Norte de Marruecos. Macla, n. 24 (junio 2019), pp. 00-00.La asociación talco-fengita como indicador de condiciones metamórficas de HP se conoce desde la publicación de Abraham y Schreyer (1976). Los estudios experimentales y teóricos han demostrado que esta asociación es estable en condiciones 10kbar. El hallazgo de esta asociación en las rocas metapelíticas triásicas de la unidad de Beni Mezala (Unidades de Federico de la Zona Interna del Rif) ha hecho que en este trabajo se pretenda caracterizar la asociación talco-fengita de los esquistos blancos de la unidad de Beni Mezala mediante XRD, SEM y HRTEM, con el fin de corroborar la existencia de la misma bajo condiciones de P y T diferentes a las previamente sugeridas por otros autores. Los esquistos blancos consisten en bandas claras y pardas subparalelas, con tamaños de grano muy pequeño. Los diagramas de XRD indican que están constituidos por Qz, Fps, Ms, ML, Tlc, Kln y Hem. Las imágenes de BSE y de EDS indican que las áreas pardas de la imagen óptica, están constituidas por fengita, rutilo y feldespato potásico describiendo la foliación, mientras que las bandas claras consisten en mica blanca potásica desorientada, vermiculita, minerales del grupo del caolín, cuarzo y albita. Las zonas más oscuras son fundamentalmente ML. Sin embargo, no se han identificado granos discretos de talco, ni en microscopía óptica ni en BSE-SEM se deduce que, probablemente, el talco pudiera estar intercrecido con la fengita a escala nanométrica. Las imágenes de HRTEM muestran la presencia de intercrecimientos de fengita, vermiculita y ML. Algunas difracciones electrónicas obtenidas en grandes paquetes de fengitas exhiben reflexiones que podrían ser atribuibles al talco. Las imágenes de franjas permiten observar espaciados de 9,3 Å. Los datos de microanálisis de estas zonas presentan contenidos en Mg superiores a 0,57 apfu y ocupación octaédrica de hasta 2,24 apfu. Todos estos resultados sugieren que el talco forma una estructura en dominios dentro de los paquetes de fengitas.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech
La ISO 9000 y los resultados económico-financieros empresariales: el caso de los sectores de la construcción y del metal en Galicia
No cabe duda que trabajar con calidad es ser competitivo. Así, desde un punto de vista normativo, son
muchos los trabajos que justifican este interés; sin embargo, desde una perspectiva empírica, la
escasez de estudios realizados, ha dado lugar a resultados no sólo limitados sino ampliamente
contradictorios, cuestionando gran parte de las ventajas asociadas a la posesión de una ISO 9000 tan
pródigamente difundidas a nivel teórico.
Todo ello nos ha llevado a plantear un estudio empírico en el que, a través de la comparación de los
datos obtenidos para dos sectores en Galicia -construcción y productos metálicos-, se analizan los
efectos que la implantación de dichas normas han tenido en los resultados económico-financieros de
las empresas pertenecientes a dichos sectores.Needless to say, working with quality means being competitive. From a normative point of view, there
are many works that justify this interest. However, from an empiric perspective, the shortage of studies
that have been carried out has produced results not only limited but also broadly contradictory. These
results have questioned a great part of the advantages related to the possession of an ISO 9000,
although these advantages had been widely presented at a theoretical level.
All these aspects have taken us to outline an empiric study through the comparison of data obtained
from two sectors in Galicia, construction and metalmechanics. We analyse the effects of the
implementation of these norms on the economic and financial results of the companies belonging to
these sectors
Case Studies As Practical Teaching In The New Marketing Courses
The European Higher Education Area is assuming a change in the teaching-learning of all European universities. The area of Marketing, traditionally characterized by being at the forefront in terms of educational innovation, faces the challenge of finding new tools to facilitate the work of students by encouraging their involvement in the acquisition of new skills. This paper analyzes the capacity that the development of case studies has to develop skills and competencies by the students, which are defendants in the framework of the European Higher Education Area to suit the environment established in the labor market. To this end, it is analyzed the experience and the main conclusions of the practices carried out at the University of Castilla-La Mancha, with the participation of student groups at an international conference aimed at developing teaching cases in public and nonprofit marketing
Laboratory and telescope demonstration of the TP3-WFS for the adaptive optics segment of AOLI
AOLI (Adaptive Optics Lucky Imager) is a state-of-art instrument that combines adaptive optics (AO) and lucky imaging (LI) with the objective of obtaining diffraction limited images in visible wavelength at mid- and big-size ground-based telescopes. The key innovation of AOLI is the development and use of the new TP3-WFS (Two Pupil Plane PositionsWavefront Sensor). The TP3-WFS, working in visible band, represents an advance over classical wavefront sensors such as the Shack-Hartmann WFS (SH-WFS) because it can theoretically use fainter natural reference stars, which would ultimately provide better sky coverages to AO instruments using this newer sensor. This paper describes the software, algorithms and procedures that enabled AOLI to become the first astronomical instrument performing real-time adaptive optics corrections
in a telescope with this new type of WFS, including the first control-related
results at the William Herschel Telescope (WHT)This work was supported by the Spanish Ministry of Economy under the projects AYA2011-29024, ESP2014-56869-C2-2-P, ESP2015-69020-C2-2-R and DPI2015-66458-C2-2-R, by project 15345/PI/10 from the Fundación Séneca, by the Spanish Ministry of Education under the grant FPU12/05573, by project ST/K002368/1 from the Science and Technology Facilities Council and by ERDF funds from the European Commission. The results presented in this paper are based on observations made with the William Herschel Telescope operated on the island of La Palma by the Isaac Newton Group in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofísica de Canarias. Special thanks go to Lara Monteagudo and Marcos Pellejero for their timely contributions
- …