Twisted flux tube emergence from the convection zone to the corona

3D numerical simulations of a horizontal magnetic flux tube emergence with different twist are carried out in a computational domain spanning the upper layers of the convection zone to the lower corona. We use the Oslo Staggered Code to solve the full MHD equations with non-grey and non-LTE radiative transfer and thermal conduction along the magnetic field lines. The emergence of the magnetic flux tube input at the bottom boundary into a weakly magnetized atmosphere is presented. The photospheric and chromospheric response is described with magnetograms, synthetic images and velocity field distributions. The emergence of a magnetic flux tube into such an atmosphere results in varied atmospheric responses. In the photosphere the granular size increases when the flux tube approaches from below. In the convective overshoot region some 200km above the photosphere adiabatic expansion produces cooling, darker regions with the structure of granulation cells. We also find collapsed granulation in the boundaries of the rising flux tube. Once the flux tube has crossed the photosphere, bright points related with concentrated magnetic field, vorticity, high vertical velocities and heating by compressed material are found at heights up to 500km above the photosphere. At greater heights in the magnetized chromosphere, the rising flux tube produces a cool, magnetized bubble that tends to expel the usual chromospheric oscillations. In addition the rising flux tube dramatically increases the chromospheric scale height, pushing the transition region and corona aside such that the chromosphere extends up to 6Mm above the photosphere. The emergence of magnetic flux tubes through the photosphere to the lower corona is a relatively slow process, taking of order 1 hour.Comment: 53 pages,79 figures, Submitted to Ap

Improved faulted phase selection algorithm for distance protection under high penetration of renewable energies

The high penetration of renewable energies will affect the performance of present protection algorithms due to fault current injection from generators based on power electronics. This paper explains the process followed for analyzing this effect on distance protection and the development of a new algorithm that improves its performance in such a scenario. First of all, four commercial protection relays were tested before fault current contribution from photovoltaic system and full converter wind turbines using the hardware in the loop technique. The analysis of results obtained, jointly with a theoretical analysis based on commonly used protection strategy of superimposed quantities, lead to a conclusion about the cause of observed wrong behaviors of present protection algorithms under a high penetration of renewables. According to these conclusions, a new algorithm has been developed to improve the detection of faulted phase selection and directionality on distance protection under a short circuit current fed by renewable energy sources. © 2020 by the author

Efecto de la música sobre la ansiedad y el dolor en pacientes con ventilación mecánica

La capacidad de la música para aliviar la ansiedad o el dolor ha sido utilizada ampliamente a lo largo de la historia. Objetivo: Examinar los efectos de la música sobre la ansiedad y el dolor en pacientes con ventilación mecánica invasiva. Diseño: Un ensayo aleatorizado controlado con medidas repetidas. Material y método: estudio prospectivo experimental con distribución aleatoria, en un hospital universitario de tercer nivel, de enero de 2009 a junio de 2010. La muestra fue de 44 participantes. La intervención consistió en una sesión musical de 30 min, con auriculares, en habitación individual. Al grupo control se le mantuvo sin ningún cambio en el entorno habitual de una unidad de cuidados intensivos. A cada paciente se le realizaron un mínimo de 3 y un máximo de 5 sesiones musicales. La música fue escogida por el paciente entre una selección musical preparada por el equipo investigador. La ansiedad, el dolor y las variables hemodinámicas frecuencia cardiaca, frecuencia respiratoria, tensión arterial sistólica y diastólica se midieron en el momento basal, tras la sesión musical y una hora después de la audición musical. Resultados: La musicoterapia disminuyó significativamente la ansiedad (p = 0,000), medida con la escala de Ansiedad Estado-Rasgo (STAI). No hubo diferencia significativa en los niveles de dolor (p = 0,157), medida con la escala visual analógica. No se demostró efecto sumativo a lo largo de las múltiples sesiones. Conclusión: La música reduce la ansiedad en los pacientes con ventilación mecánica invasiva, pudiéndose establecer como una herramienta no farmacológica a añadir a las opciones terapéuticas de las cuales disponemos

Nutritive Value and Cattle Preferences in an Old Boer Lovegrass Stand Treated with Biosolids in Cananea, Sonora, México

Boer lovegrass (Eragrostis curvula var. conferta) is an introduced species planted to increase productivity on deteriorated rangelands in northern Mexico. Forage production with Boer lovegrass achieves an increase of two to three fold when compared to native grasses, however, as stands became old, pasture productivity and forage quality declines due to a reduction in available nutrients causing a reduction in grazing capacity and beef production. Previous studies have shown that biosolids enhance seedling establishment, plant growth and increases forage production in the species, but no data is available to measure changes in forage quality and animal performance. This study was conducted to evaluate pasture nutritive value and cattle preferences on a 15 year old Boer lovegrass stand three summers following biosolids application

Identifying seawater intrusion in coastal areas by means of 1D and quasi-2D joint inversion of TDEM and VES data

Seawater intrusion is an increasingly widespread problem in coastal aquifers caused by climate changes –sea-level rise, extreme phenomena like flooding and droughts– and groundwater depletion near to the coastline. To evaluate and mitigate the environmental risks of this phenomenon it is necessary to characterize the coastal aquifer and the salt intrusion. Geophysical methods are the most appropriate tool to address these researches. Among all geophysical techniques, electrical methods are able to detect seawater intrusions due to the high resistivity contrast between saltwater, freshwater and geological layers. The combination of two or more geophysical methods is recommended and they are more efficient when both data are inverted jointly because the final model encompasses the physical properties measured for each methods. In this investigation, joint inversion of vertical electric and time domain soundings has been performed to examine seawater intrusion in an area within the Ferragudo-Albufeira aquifer system (Algarve, South of Portugal). For this purpose two profiles combining electrical resistivity tomography (ERT) and time domain electromagnetic (TDEM) methods were measured and the results were compared with the information obtained from exploration drilling. Three different inversions have been carried out: single inversion of the ERT and TDEM data, 1D joint inversion and quasi-2D joint inversion. Single inversion results identify seawater intrusion, although the sedimentary layers detected in exploration drilling were not well differentiated. The models obtained with 1D joint inversion improve the previous inversion due to better detection of sedimentary layer and the seawater intrusion appear to be better defined. Finally, the quasi-2D joint inversion reveals a more realistic shape of the seawater intrusion and it is able to distinguish more sedimentary layers recognised in the exploration drilling. This study demonstrates that the quasi-2D joint inversion improves the previous inversions methods making it a powerful tool applicable to different research areas.info:eu-repo/semantics/publishedVersio

An Ecological Alternative to Snodgrass & Vanderwart: 360 High Quality Colour Images with Norms for Seven Psycholinguistic Variables

This work presents a new set of 360 high quality colour images belonging to 23 semantic subcategories. Two hundred and thirty-six Spanish speakers named the items and also provided data from seven relevant psycholinguistic variables: age of acquisition, familiarity, manipulability, name agreement, typicality and visual complexity. Furthermore, we also present lexical frequency data derived from Internet search hits. Apart from the high number of variables evaluated, knowing that it affects the processing of stimuli, this new set presents important advantages over other similar image corpi: (a) this corpus presents a broad number of subcategories and images; for example, this will permit researchers to select stimuli of appropriate difficulty as required, (e.g., to deal with problems derived from ceiling effects); (b) the fact of using coloured stimuli provides a more realistic, ecologically-valid, representation of real life objects. In sum, this set of stimuli provides a useful tool for research on visual object-and word- processing, both in neurological patients and in healthy controls

Complex systems representing effective connectivity in patients with Type One diabetes mellitus

Background Type 1 diabetes mellitus (T1D) affects the entire cellular network of the organism. Some patients develop cognitive disturbances due to the disease, but several authors have suggested that the brain develops compensatory mechanisms to minimize or prevent neuropsychological decline. The present study aimed to assess the effective connectivity underlying visuospatial working memory performance in young adults diagnosed with T1D using neuroimaging techniques (fMRI). Methods Fifteen T1D right-handed, young adults with sustained metabolic clinical stability and a control group matched by age, sex, and educational level voluntarily participated. All participants performed 2 visuospatial working memory tasks using a block design within an MRI scanner. Regions of interest and their signal values were obtained. Effective connectivity by means of structural equations models was evaluated for each group and task through maximum likelihood estimation, and the model with the best fit was chosen in each case. Results Compared to the control group, the patient group showed a significant reduction in brain activity in the two estimated networks (one for each group and task). The models of effective connectivity showed greater brain connectivity in healthy individuals, as well as a more complex network. T1D patients showed a pattern of connectivity mainly involving the cerebellum and the red nucleus. In contrast, the control group showed a connectivity network predominantly involving brain areas that are typically activated while individuals are performing working memory tasks. Conclusion Our results suggest a specific effective connectivity between the cerebellum and the red nucleus in T1D patients during working memory tasks, probably reflecting a compensatory mechanism to fulfill task demands

Relativistically extended Blanchard recurrence relation for hydrogenic matrix elements

General recurrence relations for arbitrary non-diagonal, radial hydrogenic matrix elements are derived in Dirac relativistic quantum mechanics. Our approach is based on a generalization of the second hypervirial method previously employed in the non-relativistic Schr\"odinger case. A relativistic version of the Pasternack-Sternheimer relation is thence obtained in the diagonal (i.e. total angular momentum and parity the same) case, from such relation an expression for the relativistic virial theorem is deduced. To contribute to the utility of the relations, explicit expressions for the radial matrix elements of functions of the form $r^\lambda$ and $\beta r^\lambda$ ---where $\beta$ is a Dirac matrix--- are presented.Comment: 21 pages, to be published in J. Phys. B: At. Mol. Opt. Phys. in Apri

Late Holocene climate variability in the southwestern Mediterranean region: an integrated marine and terrestrial geochemical approach

A combination of marine (Alboran Sea cores, ODP 976 and TTR 300 G) and terrestrial (Zoñar Lake, Andalucia, Spain) geochemical proxies provides a high-resolution reconstruction of climate variability and human influence in the southwestern Mediterranean region for the last 4000 years at inter-centennial resolution. Proxies respond to changes in precipitation rather than temperature alone. Our combined terrestrial and marine archive documents a succession of dry and wet periods coherent with the North Atlantic climate signal. A dry period occurred prior to 2.7 cal ka BP – synchronously to the global aridity crisis of the third-millennium BC – and during the Medieval Climate Anomaly (1.4–0.7 cal ka BP). Wetter conditions prevailed from 2.7 to 1.4 cal ka BP. Hydrological signatures during the Little Ice Age are highly variable but consistent with more humidity than the Medieval Climate Anomaly. Additionally, Pb anomalies in sediments at the end of the Bronze Age suggest anthropogenic pollution earlier than the Roman Empire development in the Iberian Peninsula. The Late Holocene climate evolution of the in the study area confirms the see-saw pattern between the eastern and western Mediterranean regions and the higher influence of the North Atlantic dynamics in the western Mediterranean