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New model to tune the dielectric properties of dense and half-dense sintered polycrystalline cu-doped Ni–Zn ferrite

Sintered polycrystalline Cu-doped Ni–Zn ferrite specimens have been successfully prepared by a conventional ceramic method using different pressure-temperature-time cycles. The studied samples, with an average grain size of 5–25 μm and a porosity less than 0.20, exhibited a high effective complex permittivity-real part () and a minimum dielectric loss above 1 GHz. was successfully calculated using the Bruggeman-Landauer equation for the lowest angular frequencies and the Jayasundere-Smith equation for the highest one. To accurately predict the values of , both equations must be improved considering the Zheng approach. The need to change the model highlights the change in the polarization mechanism that occurs at high angular frequencies. The two proposed modified equations allow predicting the for a dense and half-dense ferrite from its microstructure (porosity) and its constituent permittivities (grain and air).Funding for open access charge: CRUE-Universitat Jaume

Influence of microstructure and magnetizing mechanisms on magnetic complex permeability (imaginary part) of a Cu-doped Ni-Zn polycrystalline ferrite

The complex permeability of the Cu-doped Ni–Zn polycrystalline ferrites is strongly dependent on microstructure, particularly on relative density (ϕ) and average grain size (G), as it has been shown in a previous study developed at a constant angular frequency (107 Hz). In this study, the previous microstructural model proposed has been extended to an angular frequency range (from 106 to 109 Hz) demonstrating its validity and reliability. In addition, domain-wall motion and spin rotation contributions to magnetic permeability have been individually considered in the mathematical model, highlighting the relative influence of each magnetizing mechanism at different angular frequencies.Funding for open access charge: CRUE-Universitat Jaume

Bilateral Macular Hole Related to Tamoxifen Low-Dose Toxicity

Bilateral macular hole is a rare secondary effect of tamoxifen, a condition which is probably underdiagnosed. We describe the case of a 63-year-old woman who had received low-dose treatment with tamoxifen for 10 years. She presented with a best-corrected visual acuity of 20/40 in both eyes and bilateral macular hole with posterior hyaloid attachment. No reflective deposits were observed. A 23-gauge pars plana vitrectomy with internal limiting membrane peeling and gas tamponade was performed in the right eye with no anatomical or functional improvement. The most accepted mechanism of macular hole related to tamoxifen is Müller cell toxicity with retinal tissue loss. Therefore, it seems that the standard procedure used in idiopathic macular hole is not the optimal choice, due to a different pathogenic mechanism

In operando characterization of the ionic conductivity dependence on liquid transient phase and microstructure of cold-sintered Bi2O3-doped Li1.3Al0.3Ti1.7(PO4)3 solid-state electrolyte

A disruptive sintering technique, Cold Sintering Process (CSP), has been used to produce cold-sintered samples of Bi2O3-doped Li1.3Al0.3Ti1.7(PO4)3 (LATP) as solid-state electrolyte (SSE). An in operando impedance study has been performed to shed light on this sintering process. In this work, Bi2O3 and 3 m acetic acid solution sintering aids were synergistically added to LATP powders to sinter at low temperature. Effects of Transient Liquid Phase (TLP) content on the sintering behavior, phase composition, microstructure, and electrochemical properties were all investigated for a LATP doped with 2 wt% Bi2O3 (optimal content) solid-state electrolyte (SSE). The data revealed that the final electrical properties, which are the key parameter decisive for their application, are defined by the following sintering parameters: Transient Liquid Phase (TLP) content, temperature, pressure, and dwell time. Using acetic acid 3 m as TLP, LATP-based samples can be cold-sintered at optimized sintering conditions of 150 °C and 700 MPa of uniaxial pressure for 90 min. The resultant SSE shows a high ionic conductivity (4.5·10−5 S cm−1) at room temperature (RT) and relative density (∼95%), which demonstrates the effectiveness of the low-temperature sintering process by optimizing the ionic conductivity of LATP-based SSE, also reducing preparation costs and CO2 emissions.Funding for open access charge: CRUE-Universitat Jaume

Microstructure-dependent magnetic permeability in ferrites from nanoparticles

Ferrite samples of composition Cu0.12Ni0.23Zn0.65(Fe2O4) have been prepared by a conventional ceramic process using different sintering temperatures and dwell times. The average particle size is around 25–30 nm and, after sintering, the average grain size increases to 0.2–5 μm and the relative density is between 88 and 95 % of the theoretical density. This paper shows that the mathematical model previously tested on ferrite microparticles with the same composition, is also capable to fit the measured complex magnetic permeability-imaginary part u11 and to explain why this magnetic property decreases when the particle size of the starting powder changes from micro to nano size. The model confirms the dependence of the magnetizing mechanisms (spin rotation and domain-wall motion) on the two microstructural parameters: average grain size (G) and relative density o/ of the sintered body

Frequency dispersion model of the complex permeability of soft ferrites in the microwave frequency range

The complex permeability of Cu-doped nickel-zinc polycrystalline ferrites is strongly dependent on microstructure, particularly, on relative density (urn:x-wiley:00027820:media:jace18267:jace18267-math-0001) and average grain size (urn:x-wiley:00027820:media:jace18267:jace18267-math-0002). In this study, a mathematical model, able to fit the measured magnetic permeability spectra from 106 to 109 Hz, is proposed and validated for a width range of average grain sizes (3.40–23.15 μm) and relative densities (0.83–0.96). To the authors’ knowledge, domain-wall motion and spin rotation contributions to magnetic permeability have been integrated jointly with the microstructure for the first time in the proposed model, highlighting the relative influence of each magnetizing mechanism and microstructure on the magnetic permeability at different angular frequencies.Funding for open access charge: CRUE-Universitat Jaume

IdM@tI: Red de Innovación Docente en Materiales Interuniversitaria

IdM@ti es una red interuniversitaria formada por profesores de ciencia e ingeniería de materiales de varias universidades del estado español, comprometidos con la innovación docente. Se describe su origen, motivación y objetivos así como las actividades que ha realizado hasta el momento y los retos que se marca para el futuro

Aprendizaje y autoevaluación online de estudiantes universitarios: la matemática financiera en entornos virtuales

[EN] The course on Financial Mathematics is a compulsory course, part of the Basic Formation in three undergraduate degrees at Jaume I university: Finance and Accounting, Economics and Business Management. It is a mathematics course, with a high number of enrolled students and with a group of teachers with special characterstics. Due to this things, the implementation of an individualized monitoring system becomes complex. In this paper we present a methodological innovation proposal conducted during the school year 2014/15. The innovation consists of the virtual and formative self-assessment of three assignments. This innovation focuses on the involvement of students in a reflexive and continuous learning process. Furthermore, it pursuits a suitable and timely feedback that helps students to improve their academic performance. Our empirical results show that the virtual and formative self-assessment process has had a positive effect so in the number of students that attend the final exam as in the number of students that pass successfully the course.[ES] Matemática de las Operaciones Financieras es una asignatura de Formación Básica de primer año que todos los alumnos tienen que cursar obligatoriamente en los grados universitarios de Economía, Contabilidad y Finanzas y Administración de Empresas de la Universidad Jaume I de Castellón. Por su naturaleza matemática, por el elevado número de alumnos matriculados y por las características de los profesores que imparten docencia, resulta difícil un seguimiento individualizado del aprendizaje del estudiantado. La presente comunicación expone una propuesta de innovación metodológica introducida en dicha asignatura durante el curso 2014/2015. La innovación consiste en la autoevaluación virtual formativa de los alumnos de tres casos prácticos. El objetivo es que los alumnos reflexionen sobre su aprendizaje de un modo continuo y autónomo. Además, se pretende que reciban un feedback eficaz y oportuno que les ayude a mejorar su rendimiento académico. El análisis empírico presentado demuestra que la autoevaluación formativa virtual propuesta ha influido muy positivamente tanto en el aumento del porcentaje de alumnos que se presentan al examen final como en su nota media.Cabedo Semper, J.; Maset Llaudes, M.; Segarra Adel, N. (2017). Aprendizaje y autoevaluación online de estudiantes universitarios: la matemática financiera en entornos virtuales. En In-Red 2016. II Congreso nacional de innovación educativa y docencia en red. Editorial Universitat Politècnica de València. https://doi.org/10.4995/INRED2016.2016.4354OC

Brain structural signatures of negative symptoms in depression and schizophrenia.

Negative symptoms occur in several major mental health disorders with undetermined mechanisms and unsatisfactory treatments; identification of their neural correlates might unveil the underlying pathophysiological basis and pinpoint the therapeutic targets. In this study, participants with major depressive disorder (n = 24), schizophrenia (n = 22), and healthy controls (n = 20) were assessed with 10 frequently used negative symptom scales followed by principal component analysis (PCA) of the scores. A linear model with the prominent components identified by PCA was then regressed on gray and white-matter volumes estimated from T1-weighted magnetic resonance imaging. In depressed patients, negative symptoms such as blunted affect, alogia, withdrawal, and cognitive impairment, assessed mostly via clinician-rated scales were inversely associated with gray matter volume in the bilateral cerebellum. In patients with schizophrenia, anhedonia, and avolition evaluated via self-rated scales inversely related to white-matter volume in the left anterior limb of internal capsule/anterior thalamic radiation and positively in the left superior longitudinal fasiculus. The pathophysiological mechanisms underlying negative symptoms might differ between depression and schizophrenia. These results also point to future negative symptom scale development primarily focused on detecting and monitoring the corresponding changes to brain structure or function.This work was supported by Brain and Behavior Research Foundation (NARSAD) and Medical Research Council (MRC) awards to GKM, and by the Wellcome Trust/MRC Behavioural and Clinical Neuroscience Institute, University of Cambridge. We thank Dr. Zheng Ye for her help with image analysis and technical support, Niels Reinders and staff at the Wolfson Brain Imaging Centre for help with data collection, and staff at IAPT, CAMEO and the Rehabilitation and Recovery Service in the Cambridgeshire and Peterborough NHS Foundation Trust for help with recruitment. The study was supported by infrastructure provided by the Wellcome Trust/MRC Behavioural and Clinical Neuroscience Institute at the University of Cambridge.This is the final version published by Frontiers here: http://journal.frontiersin.org/Journal/10.3389/fpsyt.2014.00116/abstract