2,243 research outputs found
Super-Planckian far-field radiative heat transfer
We present here a theoretical analysis that demonstrates that the far-field radiative heat transfer between objects with dimensions smaller than the thermal wavelength can overcome the Planckian limit by orders of magnitude. To guide the search for super-Planckian far-field radiative heat transfer, we make use of the theory of fluctuational electrodynamics and derive a relation between the far-field radiative heat transfer and the directional absorption efficiency of the objects involved. Guided by this relation, and making use of state-of-the-art numerical simulations, we show that the far-field radiative heat transfer between highly anisotropic objects can largely overcome the black-body limit when some of their dimensions are smaller than the thermal wavelength. In particular, we illustrate this phenomenon in the case of suspended pads made of polar dielectrics like SiN or SiO2. These structures are widely used to measure the thermal transport through nanowires and low-dimensional systems and can be employed to test our predictions. Our work illustrates the dramatic failure of the classical theory to predict the far-field radiative heat transfer between micro- and nanodevicesWe acknowledge funding from
the Spanish MINECO (FIS2015-64951-R, MAT2014-53432-
C5-5-R, FIS2014-53488-P, FIS2017-84057-P), the Comunidad
de Madrid (S2013/MIT-2740), the European Union
Seventh Framework Programme (FP7-PEOPLE-2013-CIG-
630996, FP7-PEOPLE-2013-CIG-618229), and the European
Research Council (ERC-2011-AdG-290981 and ERC-2016-
STG-714870). V.F.-H. acknowledges support from “la Caixa”
Foundation and J.C.C. thanks the DFG and SFB767 for
sponsoring his stay at the University of Konstanz as Mercator Fello
Subunits Common to RNA Polymerases
RNA polymerases are heteromultimeric complexes responsible of RNA synthesis. In yeast, as in the other eukaryotes, these complexes contain five common subunits (Rpb5, Rpb6, Rpb8, Rpb10 and Rpb12) that must have similar functions in the three RNA polymerases. However, some of these proteins have been shown to also have specific roles. In the last few decades, substantial progress has been made to understand the role of these common subunits in transcription, but their participation in the activity of each enzyme remains unclear. This review gives a comprehensive overview of current knowledge on the five common subunits of eukaryotic RNA pol, placing attention not only on their common roles in the activity of the RNA pols but also on describing specific roles for some of the complexes
Stable isotopes applied to the study of the concrete/bentonite interaction in the FEBEX in situ test
Stable isotope analysis was carried out on a set of samples from the concrete-bentonite interface from the FEBEX real-scale in-situ experiment. The concrete and bentonite that simulated the engineering barriers system of a deep geological repository have interacted for 13 years in saturated conditions up to dismantling. The monitoring of the experiment during the years of operation has made possible to know not only the baseline status but also the evolution of the system and the mass transfer processes. Thus, the FEBEX experiment has been a unique opportunity to study concrete degradation within a broader multi-proxy approach under real-scale repository conditions. Analysis of carbon and oxygen isotopes of carbonates in groundwater, concrete and clay have provided evidence of how dissolution and mass transfer processes occur in the Engineered Barrier System (EBS). Spatial distribution of δ13C values points to the existence of a dominant process of diffusion of carbon species from bentonite towards the concrete/bentonite interface. Variations in δ18O values suggest a non-homogeneous geochemical and hydraulic behavior of the EBS in the vicinity of both, the granite-concrete interface and the concrete-bentonite interface. These differences might be related to different degrees of exposure of each sample to bentonite porewater, groundwater and concrete/bentonite leachates. This seem to be in agreement with the existence of different chemical environments depending on the location of the samples in the experiment.The work was financially supported by the European Union's Horizon 2020 grant
agreement n° 662147 (www.cebama.eu) and the Annex XLII of the ENRESA-CIEMAT
framework agreement. The FEBEX project was financed by ENRESA and the EC
Contracts FI4W-CT95-006 and FIKWCT-2000-00016. The FEBEX-DP Consortium
(NAGRA, SKB, POSIVA, CIEMAT, KAERI) financed the dismantling operation and onsite determinations in 2015
Applications of infrared thermography in sports. A review
La termografía infrarroja (TI) registra el calor irradiado de un cuerpo, que es emitido en un rango del espectro electromagnético que la visión humana no es capaz de identificar. La respuesta térmica depende de una serie de ajustes fisiológicos específicos como la homeostasis corporal y salud del deportista, lo cual permite establecer interesantes aplicaciones en el deporte. El objetivo de este trabajo ha sido revisar la literatura en torno a las aplicaciones de la TI en el ámbito del deporte, y proponer las características óptimas del registro en relación al evaluado, las condiciones ambientales y la cámara utilizada. Concluimos que la principal contribución de la TI en el ámbito del deporte es ayudar a identificar
signos de lesión antes de que la lesión se produzca, permitiéndonos actuar de manera preventiva durante el proceso de entrenamientoInfrared thermography (IRT) records the radiant heat of a body, which is emitted in the range of the electromagnetic spectrum that human vision is not able to identify. The thermal response depends on a number of specific physiological adjustments as body homeostasis and athlete’s health, which allow us to establishing interesting applications in sport. The aim of this study was to review the literature on IRT applications in sports, and to propose the optimal characteristics of the register in terms of the subject, the environmental conditions and the camera used. We conclude that the main contribution of IRT in the field of sport is to help identify signs of injury before it occurs, allowing us to act proactively along the training proces
Perfiles de creencias epistemológicas sobre la lectura y su papel en la comprensión de textos múltiples
Introduction. The aim of this study was to analyse the role of epistemological beliefs
and reading beliefs in the comprehension of multiple texts which presented conflicting
positions about a controversial topic (nuclear energy). More specifically, we investigated
the influence of the multidimensional configuration of epistemological and reading beliefs on multiple text comprehension. Method. The participants were 476 university students from two different Spanish universities, and diverse studies (Humanities, Health Sciences, Architecture and Engineering). In a whole-class session, the Epistemological Beliefs Questionnaire (EQEBI) and the Reader Belief Questionnaire were first administered. In the second part of the session participants completed the prior knowledge questionnaire and performed the multiple text comprehension task. Results. Using cluster analysis we identified two distinct beliefs profiles: sophisticated, in which the more sophisticated epistemological beliefs were associated to more transactional and less transmissive reading beliefs; and naïve, in which the more naïve epistemological beliefs were associated to less transactional and more transmissive reading beliefs. Relationships were found between profiles and gender and domain of knowledge. In addition, after controlling prior knowledge, students with a more sophisticated epistemological and reading beliefs’ profile obtained a higher level of multiple text comprehension than those with a more naïve profile.
Conclusion. Consistent with prior research, we may interpret that students who understand
knowledge in a more sophisticated way tend to view reading less as a transmissive
process and more transforming of knowledge; therefore, they get involved in a deeper
comprehension of the different sources and this favours their ability to process information
and make inferences – at an intra and inter textual levelIntroducción. El ojetivo de este estudio fue analizar el papel de las creencias epistemológicas y de lectura en la comprensión de multiples textos que presentan posiciones contradictorias sobre un tema controvertido (la energía nuclear). En concreto, se investigó la influencia de la configuración multidimensional de creencias epistemológicas y de lectura en la comprensión de múltiples textos. Método. En el estudio participaron 476 estudiantes universitarios de dos universidades españolas y de distintas titulaciones (Humanidades, Ciencias de la Salud, Arquitectura e Ingeniería). Durante una clase se aplicó el Epistemological Beliefs Questionnaire (EQEBI) y el Reader Belief Questionnaire. En la siguiente, los participantes contestaron el cuestionario de conocimiento previo y realizaron la tarea de comprensión a partir de múltiples textos. Resultados. Se identificaron dos perfiles de creencias a través de un análisis de cluster: sofisticado, en el que las creencias epistemológicas sofisticadas están asociadas con creencias sobre la lectura más transaccionales y con las menos transmisivas; e ingénuo, en el que las creencias epistemológicas más ingenuas están asociadas con creencias sobre la lectura menos trasaccionales y con las más transmisivas. Se encontraron relaciones entre los perfiles y el género y el dominio de conocimiento. Los resultados muestran también que, una vez controlado el conocimiento previo, los estudiantes con creencias epistemológicas y de lectura más sofisticadas obtienen mejores resultados en la tarea de comprensión a partir de múltiples textos que aquellos que responden a un perfil ingenuo.
Conclusion. Según los resultados, que coinciden con los de otros estudios, interpretaríamos que los estudiantes que conciben el conocimiento de una manera más sofisticada tienden a considerar la lectura menos como un proceso transmisivo y más como una transformación del conocimiento; por ello realizan una comprensión más profunda de las diferentes fuentes y esto favorece su capacidad de procesar información y hacer inferencias –en un nivel tanto inter como intra textualThis work was funded under the National Programme for Basic Research Projects 2014–2016 by the Spanish Ministry of Economy and Competitiveness (Grant EDU2013-46606-C2-1 & 2-R
Geochemical interactions at the steel-bentonite interface caused by a hydrothermal gradient
Bentonites are used in deep geological disposal facilities as an engineered barrier to isolate high level radioactive waste, contained in metallic canisters. The present study, performed at laboratory scale, evaluated the behaviour of MX-80 (Na-bentonite) and FEBEX (Ca-Mg-Na-bentonite) in contact with carbon steel, subjected to a hydrothermal gradient. A dominant Na-Cl-SO4 saline solution was injected towards the compacted bentonite from the top, while a heater, located at the bottom in contact with the steel disc, maintained a constant temperature of 100 °C. The cells were studied after one and six months of interaction. Changes in the physical (water content and specific surface area) and chemical (cation exchange capacity and element distribution) properties of the bentonite were observed, as well as the formation of a corrosion layer on the steel, at the interface with bentonite, mainly composed of magnetite, maghemite and hematite. The bentonites were mainly altered at the mm scale, being enriched in iron content, and changing their ion distribution to Ca-dominant smectite (in MX-80 bentonite)This
project has received funding from the European Union’s Horizon 2020
research and innovation programme 2014-2018 under grant agreement
N◦84759
Impact of a tire fire accident on soil pollution and the use of clay minerals as natural geo-indicators
Following the occurrence of a fire at a tire landfill in the surrounding area of Madrid City (Spain), polycyclic aromatic hydrocarbons (PAHs) and trace elements present in soils were analyzed to assess the impact of the fire. The capacity of the soils’ clay mineral fraction to reflect this air pollution incident was studied. Fourteen soil samples were collected at different distances under the smoke plume, and they were subjected to high-performance liquid chromatography–photodiode array detection, inductively coupled plasma mass spectrometry and X-ray diffraction analyses. Clay minerals content showed a strong correlation with the pollutants potentially released in the tire fire, acenaphthene, pyrene, benzo(a)pyrene and benzo(a)fluoranthene. Trace metals Zn and Se were related to the proximity of the tire fire without any relationship with clay minerals content. This work suggests the use of natural clay minerals as potential PAHs geo-indicators in response to air pollution, complementary to current air and biological analysesThis work has been economically supported by the Ministry of Economy and Competitiveness of Spain, Project AGL2016-78490-
Thermographic imaging in sports and exercise medicine: A Delphi study and consensus statement on the measurement of human skin temperature
This is an accepted manuscript of an article published by Elsevier in Journal of Thermal Biology on 18/07/2017, available online: https://doi.org/10.1016/j.jtherbio.2017.07.006
The accepted version of the publication may differ from the final published version.© 2017 Elsevier Ltd The importance of using infrared thermography (IRT) to assess skin temperature (tsk) is increasing in clinical settings. Recently, its use has been increasing in sports and exercise medicine; however, no consensus guideline exists to address the methods for collecting data in such situations. The aim of this study was to develop a checklist for the collection of tsk using IRT in sports and exercise medicine. We carried out a Delphi study to set a checklist based on consensus agreement from leading experts in the field. Panelists (n = 24) representing the areas of sport science (n = 8; 33%), physiology (n = 7; 29%), physiotherapy (n = 3; 13%) and medicine (n = 6; 25%), from 13 different countries completed the Delphi process. An initial list of 16 points was proposed which was rated and commented on by panelists in three rounds of anonymous surveys following a standard Delphi procedure. The panel reached consensus on 15 items which encompassed the participants’ demographic information, camera/room or environment setup and recording/analysis of tsk using IRT. The results of the Delphi produced the checklist entitled “Thermographic Imaging in Sports and Exercise Medicine (TISEM)” which is a proposal to standardize the collection and analysis of tsk data using IRT. It is intended that the TISEM can also be applied to evaluate bias in thermographic studies and to guide practitioners in the use of this technique.Published versio
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