Nonequilibrium spin-dependent phenomena in mesoscopic superconductor-normal metal tunnel structures

We analyze the broad range of spin-dependent nonequilibrium transport properties of hybrid systems composed of a normal region tunnel coupled to two superconductors with exchange fields induced by the proximity to thin ferromagnetic layers and highlight its functionalities. By calculating the quasiparticle distribution functions in the normal region we find that they are spin-dependent and strongly sensitive to the relative angle between exchange fields in the two superconductors. The impact of inelastic collisions on their properties is addressed. As a result, the electric current flowing through the system is found to be strongly dependent on the relative angle between exchange fields, giving rise to a huge value of magnetoresistance. Moreover, the current presents a complete spin-polarization in a wide range of bias voltages, even in the quasiequilibrium case. In the nonequilibrium limit we parametrize the distributions with an ``effective`` temperature, which turns out to be strongly spin-dependent, though quite sensitive to inelastic collisions. By tunnel coupling the normal region to an additional superconducting electrode we show that it is possible to implement a spin-polarized current source of both spin species, depending on the bias voltages applied.Comment: Published version: 12 pages, 14 figures; new text added and one figure modifie

From rubber hands to neuroprosthetics: Neural correlates of embodiment

© 2023 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/)Our interaction with the world rests on the knowledge that we are a body in space and time, which can interact with the environment. This awareness is usually referred to as sense of embodiment. For the good part of the past 30 years, the rubber hand illusion (RHI) has been a prime tool to study embodiment in healthy and people with a variety of clinical conditions. In this paper, we provide a critical overview of this research with a focus on the RHI paradigm as a tool to study prothesis embodiment in individuals with amputation. The RHI relies on well-documented multisensory integration mechanisms based on sensory precision, where parietal areas are involved in resolving the visuo-tactile conflict, and premotor areas in updating the conscious bodily representation. This mechanism may be transferable to prosthesis ownership in amputees. We discuss how these results might transfer to technological development of sensorised prostheses, which in turn might progress the acceptability by users.Peer reviewe

Identification, Computational Examination, Critical Assessment and Future Considerations of Spatial Tactical Variables to Assess the Use of Space in Team Sports by Positional Data: a Systematic Review

The aim of the review was to identify the spatial tactical variables used to assess the use of space in team sports using positional data. In addition, we examined computational methods, performed a critical assessment and suggested future considerations. We considered four electronic databases. A total of 3973 documents were initially retrieved and only 15 articles suggested original spatial variables or different computation methods. Spatial team sport tactical variables can be classified into 3 principal types: occupied space, total field coverage by several players; exploration space, the mean location (+/- standard deviations in X- and Y-directions) of the player/team during the entire game; and dominant/influence space, the region the players can reach before any other players. Most of the studies, i.e., 55%, did not include goalkeepers (GKs) and total playing space to assess occupied space, however, several proposed new variables that considered that all playing space could be "played" (i.e. effective free-space, normalized surface area). Only a collective exploration space variable has been suggested: the major range of the geometrical centre (GC). This suggestion could be applied to assess collective exploration space variables at a sub-system level. The measurement of the dominant/influence space has been based on the Voronoi region (i.e. distance d criteria), but several studies also based their computation on the time (t). In addition, several weighted dominant areas have been suggested. In conclusion, the use of spatial collective tactical variables considering the principal structural traits of each team sport (e.g. players of both teams, the location of the space with respect to the goal, and the total playing space) is recommende

Implementación de un Sistema de Gestión de la información de las intervenciones públicas en Instituciones Educativas a nivel nacional por los órganos de línea del Programa Nacional de Infraestructura Educativa (PRONIED)

El presente trabajo de investigación tiene como objetivo general aportar un proyecto de innovación, desde la investigación, al campo de la Educación en el Perú. Y, como objetivo específico se plantea una herramienta de ayuda a la gestión pública que mejore los procesos de gestión de la información de la infraestructura educativa en el PRONIED. Como metodología de investigación, se recurrió a la consulta de fuentes secundarias como recursos bibliográficos físicos y digitales. De igual manera, se recurrió a herramientas de recojo de información primaria del tipo cualitativa como entrevistas a funcionarios del PRONIED y a expertos en el tema de investigación. Asimismo, se utilizaron a herramientas de recojo de información primaria del tipo cuantitativa como encuestas abiertas al público en general y funcionarios del PRONIED. Los principales hallazgos del trabajo de investigación evidencian que el PRONIED, en su necesidad de atender sus objetivos institucionales, debe gestionar gran cantidad de información. Para ello, ha desarrollado diversas herramientas o sistemas de información que poseen diversos niveles de desarrollo y trabajan de forma desarticulada generando dificultad en sus labores a sus funcionarios y en los ciudadanos que quieran acceder a la información relacionada a la infraestructura educativa. Para ello, se plantea un Sistema de gestión de la información que integre las diversas herramientas y sistemas de información del PRONIED a fin de agilizar los procesos internos de la institución, promoviendo la accesibilidad y trasparencia de la información hacia el interior y exterior, en línea con las políticas públicas actuales

Identification, Computational Examination, Critical Assessment and Future Considerations of Distance Variables to Assess Collective Tactical Behaviour in Team Invasion Sports by Positional Data: A Systematic Review

The aim of the study was the identification, computational examination, critical assessment and future considerations of distance variables to assess collective tactical behaviour in team invasion sports by positional data. A total of 3973 documents were initially retrieved. Finally, 72 articles met the inclusion criteria, but only 26 suggested original tactical variables based on the distance variables. The distance variables can be classified into player–player, player–space, player–ball, and Geometrical Centre (GC)–GC /player/space/goal. In addition, several nonlinear techniques have been used to analyse the synchronisation and predictability of the distance variables in team invasion sports. Player–opponent distance is of special interest in those sports in which man-marking is commonly used, and in the micro-structure close to scoring situations in all sports. In addition, player–player distances are used to measure the length and the width of the team and player–GC distance to assess the dispersion of the team. Player–space distances have been measured to assess the distance of the player/team-line to relevant areas of the playing space. Several techniques have been applied to analyse the synchronisation (i.e., Hilbert transformation and cluster analyses) and the complexity and regularity or predictability (i.e., approximate entropies, sample entropy, cross-sample entropy and average mutual information) of the distance variables in team invasion sports, revealing the lack of consensus. Although the distance variables may be interesting tactical variables when considered in isolation, it would be enriching to analyse the relationship among these variables

A kinetic study of the oscillating combustion of hydrogen and syngas in well-stirred reactors

The establishment of permanent oscillations (“limit cycles”) has been often observed in the oxidation of several hydrocarbons in premixed, non-adiabatic systems like well-stirred reactors [1-3]. In such cases, the interaction between mass flow, heat exchange and chemical kinetics results in a periodic extinction and reignition of the system. Several operating parameters have been found to influence the establishment of periodic limit cycles: beyond the fuel type and the dilution level, the oscillatory behavior is affected by the reactor temperature, pressure and residence time. Thus, the high number of parameters makes theoretical analysis a necessary step to understand the causes of such phenomena. The simplest system to be studied is the combustion of hydrogen in a premixed reactor. Such configuration was first studied by Baulch et al. [2, 4, 5]. The oxidation of CO was also separately analyzed [6, 7]. In this work, a kinetic analysis of the hydrogen and syngas oxidation in isothermal, well stirred reactors is carried out. By adopting detailed kinetic mechanisms, the boundaries of the oscillating regions are defined through a parametric study. The Rate of Production (ROP) Analysis is adopted to understand the critical reaction paths

The Influence of Antenna Height on the Measurement of Collective Variables Using an Ultra-Wide Band Based Local Positioning System in Team Sports

Ultra-wide band (UWB) based local positioning systems (LPS) are based on devices and a portable antenna set. The optimal installation height of the antennae is crucial to ensure data accuracy. Collective variables are metrics that consider at least two pairs of coordinates, which may lead to lower precision than an individual one. Therefore, the aim of this study was to compare the influence of antenna height with collective metrics using a UWB (i.e., IMU; WIMU PRO™, RealTrack Systems, Almeria, Spain) based LPS. Data acquisition was carried out in a basketball court measuring 28 × 15 m. Five devices were used; one of which was carried by a healthy and well-trained athlete (age: 38 years, mass: 76.34 kg, height 1.70 m), while each of the remaining four was positioned on a tripod in one of the four corners of the court. Four kinds of variables were extracted: (1) static distances, (2) dynamic distances, (3) static areas and (4) dynamic areas in all antenna installation modes of 0.15, 1.30 and 2.00 m. The results showed that the antenna of 1.30 m provided better accuracy for all measures (% difference range from −0.94 to 1.17%) followed by the antenna of 2.00 m (% difference range from −2.50 to 2.15%), with the antenna of 0.15 m providing the worst accuracy level (% difference range from −1.05 to 3.28%). Overall, the measurements of distance metrics showed greater accuracy than area metrics (distance % difference range from −0.85 to 2.81% and area % difference range from −2.50 to 3.28). In conclusion, the height of the antennae in basketball courts should be similar to the height at which the devices are attached to a player’s upper back. However, as the precision is sensitive to the magnitude of the measure, further studies should assess the effects of the relative height of antennae in team sports with greater playing spaces.This work is funded by Fundação para a Ciência e Tecnologia/Ministério da Ciência, Tecnologia e Ensino Superior through national funds and when applicable co-funded EU funds under the project UIDB/50008/2020

Intracortical and interhemispheric excitability changes in arm amputees: A TMS study

Objective: To evaluate cortical circuits and excitability of the motor cortex in the hemisphere contralateral to the affected (AH) and to the unaffected arm (UH), in upper limb amputees. Methods: Motor evoked potentials (MEP) were recorded in 17 subjects who had upper limb amputation: 11 trans-radial (TR) and 6 trans-humeral (TH). Motor thresholds (MT), short interval intracortical inhibition (SICI), and interhemispheric inhibition (IHI) in the available arm muscles of the stump were evaluated. Results: There was no significant difference in MT between hemispheres. SICI was preserved in TR but not in TH group. Additionally, in the TR group, the MEP amplitudes in AH were higher than in UH. A significant IHI was observed in the whole sample but not in each hemisphere or patient group. Conclusions: In our population of TR amputees, we found increased corticospinal excitability in the AH with preserved intracortical inhibition. This finding was not observed in the TH population. Significance: Understanding the changes in intracortical excitability in amputees may enhance knowledge of the functional reorganization of the brain in the post-amputation phase, bringing useful information for prosthetic rehabilitation