314 research outputs found

    Antiferromagnetic behavior in S=2 layered RbMnF4

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    Under the terms of the Creative Commons Attribution (CC BY) license to their work.The magnetic properties of layered-perovskite RbMnF4 have been investigated by neutron powder diffraction. This compound exhibits a magnetic ordering below Tc=3.7±0.2 K. The resolution of the magnetic structure at 1.5 K indicates that RbMnF4 orders as a collinear antiferromagnet. The propagation vector is k=0 and the magnetic moment of each sublattice has a value of 2.97(3) μB. The strong reduction of the observed magnetic moment should be attributed to a particularly high two-dimensional character of this compound.The research in Zaragoza has been supported by Grant No. MAT/91-681, from the Comision Interministerial deCiencia y Tecnologia.Peer Reviewe

    Magnetic structures

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    0.13-µm CMOS tunable transconductor based on the body-driven gain boosting technique with application in Gm-C filters

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    We present a low-voltage low-power CMOS tunable transconductor exploiting body gain boosting to increase the small-signal output resistance. As a distinctive feature, the proposed scheme allows the OTA transconductance to be tuned via the current biasing the gain-boosting circuit. The proposed transconductor has been designed in a 0.13-µm CMOS technology and powered from a 1.2-V supply. To show a possible application, a 0.5-MHz tunable third order Chebyshev low pass filter suitable for the Ultra Low Power Bluetooth Standard has been designed. The filter simulations show that all the requirements of the chosen standard are met, with good performance in terms of linearity, noise and power consumption

    On-Surface Thermal Stability of a Graphenic Structure Incorporating a Tropone Moiety

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    We acknowledge the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation program (ERC-2015-STG-677023 and ERC-2013-SYG-610256 NANOCOSMOS) and the innovation program under grant agreement No. 696656 (GrapheneCore1-Graphene-based disruptive technologies) and grant agreement No. 785219 (GrapheneCore2-Graphene-based disruptive technologies) for financial support. Grants PGC2018-101181-B-I00 and MAT2017-85089-C2-1-R funded by MCIN/AEI/ 10.13039/501100011033 and “ERDF A way of making Europe” by the “European Union”, and grant PID2020-113142RB-C21 funded by MCIN/AEI/ 10.13039/501100 011033 also provided financial support. We also acknowledge Comunidad de Madrid via Programa de Investigación Tecnologías 2018 (FOTOART-CM S2018/NMT-4367), the Swiss National Science Foundation (grant number 200020-182015), the NCCR MARVEL funded by the Swiss National Science Foundation (grant number 51NF40-182892) and FEDER/Junta de Andalucía-Consejería de Economía y Conocimiento (B-FQM-428-UGR20). C. S. S. and N. R. A. acknowledge Grants RYC2018-024364-I and BES-2015-072642, respectively, funded by MCIN/AEI/ 10.13039/501100011033 and “ESF Investing in your future”. I. R. M. acknowledges the University of Granada for her postdoctoral contract (Contrato Puente-Plan Propio UGR). F.V. thanks Ministerio de Universidades for the FPU grant (FPU18/05938).On-surface synthesis, complementary to wet chemistry, has been demonstrated to be a valid approach for the synthesis of tailored graphenic nanostructures with atomic precision. Among the different existing strategies used to tune the optoelectronic and magnetic properties of these nanostructures, the introduction of non-hexagonal rings inducing out-of-plane distortions is a promising pathway that has been scarcely explored on surfaces. Here, we demonstrate that non-hexagonal rings, in the form of tropone (cycloheptatrienone) moieties, are thermally transformed into phenyl or cyclopentadienone moieties upon an unprecedented surface-mediated retro–Buchner-type reaction involving a decarbonylation or an intramolecular rearrangement of the CO unit, respectively.Junta de Andalucía-Consejería de Economía y Conocimiento B-FQM-428-UGR20, BES-2015-072642, RYC2018-024364-IMCINMinisterio de Universidades FPU18/05938European Commission FOTOART-CM S2018/NMT-4367European Research CouncilSchweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung 200020-182015European Social FundUniversidad de GranadaEuropean Regional Development Fund 011033, PID2020-113142RB-C21, S2018/NMT-4367National Center of Competence in Research Materials’ Revolution: Computational Design and Discovery of Novel Materials 51NF40-182892Agencia Estatal de Investigació

    Neuropsychology of perception and facial expression of emotions: studies with children and non human primates

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    Este estudio revisa diferentes investigaciones sobre la neuropsicología de la percepción y la expresión facial de emociones en niños y en primates no humanos. Se parte de las teorías neodarwinianas sobre el origen de la emoción, que presuponen la existencia de circuitos cerebrales específicos para la expresión y comprensión del afecto y consideran que estos comportamientos son innatos y filogenéticamente determinados . A partir de la literatura examinada, las conclusiones principales que pueden extraerse son las siguientes: (1) A lo largo del primer año de vida los niños manifiestan capacidades básicas para reconocer emociones. Entre otros correlatos neurobiológicos, se ha observado que este proceso se corresponde con una mayor actividad del hemisferio cerebral derecho, frente al izquierdo. (2) En primates no humanos, y desde distintas aproximaciones experimentales, se ha encontrado un patrón similar al de nuestra especie en tareas de reconocimiento y discriminación de expresiones faciales de emociones.(3) Los lactantes expresan emociones con acciones musculares similares a las descritas en adultos. La mayoría de los autores señalan que el hemisferio cerebral derecho muestra una mayor implicación que el izquierdo, también en el caso de la expresión emocional y para todas las emociones estudiadas. No obstante desde algunas investigaciones se concluye que el hemisferio izquierdo es el dominante en el caso de la expresión de emociones positivas y el hemisferio derecho sólo en las negativas. (4) Los estudios sobre expresión facial en primates no humanos indican que existe una asimetría facial que se manifiesta en una mayor intensidad de la expresión en la mitad izquierda de la cara y, de manera correspondiente, en una mayor implicación del hemisferio cerebral derecho. Se concluye esta revisión considerando que la existencia de semejanzas anatómicas y funcionales entre adultos, niños y primates no humanos justifica el interés por los estudios de ontogenia y filogenia para conocer mejor las bases neurobiológicas que subyacen a la conducta emocionalThis study reviews different researches on the neuropsychology of facial perception and expression of emotions in children and non-human primates. It parts from neodarwinian theories on the origin of the emotion that take into account the existence of specific cerebral circuits for the expression and understanding of affect, and consider such behaviours as innate and phylogenetically determined. From literature reviewed, the main conclusions that can be extracted are the following ones: (1) During the first year of life infants show basic abilities to recognize emotions. Among other neurobiological correlates, it has been observed that this process corresponds with a greater activity of the right hemisphere, as opposed to the left one. (2) From different experimental approaches, human and non-human primates show a similar pattern in the recognition and discrimination of facial expressions of emotions. (3) Infants express emotions with similar muscular actions to those described in adults. Most of the authors also point out a greater involvement of the right hemisphere than the left one, for all of the emotional expressions. However, some studies report that right hemisphere is dominant only for the negative expressions, while the left hemisphere is for the positive ones. (4) Studies on facial expression in human and non-human primates show an asymmetry in the production of emotional responses with a greater involvement of the left side of the face (right cerebral hemisphere). This review concludes that the existence of anatomical and functional similarities in non-human primates, children and adults justifies the interest by the ontogenetic and phylogenetic studies in order to understand the neurobiological bases underlying emotional behaviou

    Cp2TiCl-catalyzed highly stereoselective intramolecular epoxide allylation using allyl carbonates

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    A useful method for the diastereoselective synthesis of vinyl substituted carbo- and heterocycles is described. Highly functionalized structures difficult to achieve by other methodologies are obtained in a single step by this procedure.This research was funded by the Ministerio de Ciencia e Innovación (Spain) (project CTQ-2011.22455). I.R.M. thanks the MEC (Spain) for a predoctoral FPU fellowship. A.M. thanks the University of Granada for a postdoctoral contract (‘Contrato Puente’). A.G.C. thanks the MICINN (Spain) for a postdoctoral contract ‘Juan de la Cierva’ and University of Granada

    General Purpose Transistor Characterized as Dosimetry Sensor of Proton Beams

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    This research has been partially funded by Junta de Andalucía (Spain), project numbers PI-0505-2017 FEDER/Junta de Andalucía-Consejería de Economía y Conocimiento Project B-TIC-468- UGR18; Ministerio de Ciencia e Innovación, Proyecto del Plan Nacional I + D: PID2019-104888 GB-I00 and Proyectos I + D + i Junta de Andalucía 2018: P18-RT-3237. This work has been also conducted in the framework of European Union H2020 ELICSIR project (grant No. 857558).A commercial pMOS transistor (MOSFET), 3N163 from Vishay (USA), has been character- ized as a low-energy proton beam dosimeter. The top of the samples’ housing has been removed to guarantee that protons reached the sensitive area, that is, the silicon die. Irradiations took place at the National Accelerator Centre (Seville, Spain). During irradiations, the transistors were biased to improve the sensitivity, and the silicon temperature was monitored activating the parasitic diode of the MOSFET. Bias voltages of 0, 1, 5, and 10 V were applied to four sets of three transistors, obtaining an averaged sensitivity that was linearly dependent on this voltage. In addition, the short-fading effect was studied, and the uncertainty of this effect was obtained. The bias voltage that provided an acceptable sensitivity, (11.4 ± 0.9) mV/Gy, minimizing the uncertainty due to the fading effect (−0.09 ± 0.11) Gy was 1 V for a total absorbed dose of 40 Gy. Therefore, this off-the-shelf electronic device presents promising characteristics as a dosimeter sensor for proton beams.Junta de Andalucia B-TIC-468-UGR18Ministry of Science and Innovation, Spain (MICINN) 2018: P18-RT-3237European Commission PI-0505-2017 FEDERJunta de Andalucia-Consejeria de Economia y Conocimiento ProjectPID2019-104888 GB-I00European Union H2020 ELICSIR project 85755

    Cryptococcus spp. isolation from excreta of pigeons (Columba livia) in and around Monterrey, Mexico

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    The presence of Cryptococcus spp. has been reported in Mexico’s capital city; however, to our knowledge there are no reports of its presence in the state of Nuevo León located in northeast Mexico. This is presumed to be because the hot and dry climate in this region does not favor cryptococcal proliferation. This study confirmed the presence of C. neoformans and C. albidus in 20% (10/50) of randomly selected fecal samples of pigeons (Columba livia) in the Monterrey metropolitan area. The presence of this yeast in the state of Nuevo León is proof of its adaptation to the typically hot climate of the area and is consistent with recent reviews of cryptococcosis cases in several local hospitals. The two species were identified and characterized through microbiological tests and molecular identification by DNA extraction and PCR amplification of highly conserved 18S ribosomal DNA using ITS1 and ITS2 as target regions. The PCR products were sequenced and compared with those reported in GenBank
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