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Thin-film stacks F|H consisting of a ferromagnetic-metal layer F and a heavy-metal layer H are spintronic model systems. Here, we present a method to measure the ultrabroadband spin conductance across a layer X between F and H at terahertz frequencies, which are the natural frequencies of spin-transport dynamics. We apply our approach to MgO tunneling barriers with thickness d = 0-6 Å. In the time domain, the spin conductance Gs has two components. An instantaneous feature arises from processes like coherent spin tunneling. Remarkably, a longer-lived component is a hallmark of incoherent resonant spin tunneling mediated by MgO defect states, because its relaxation time grows monotonically with d to as much as 270 fs at d = 6.0 Å. Our results are in full agreement with an analytical model. They indicate that terahertz spin-conductance spectroscopy will yield new and relevant insights into ultrafast spin transport in a wide range of spintronic nanostructures.
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We study the spatiotemporal dynamics of ultrafast electron spin transport across nanometer-thick copper layers using ultrabroadband terahertz emission spectroscopy. Our analysis of temporal delays, broadening, and attenuation of the spin-current pulse reveals ballisticlike propagation of the pulse peak, approaching the Fermi velocity, and diffusive features including a significant velocity dispersion. A comparison to the frequency-dependent Fick's law identifies the diffusion-dominated transport regime for distances >2 nm. These findings lay the groundwork for designing future broadband spintronic devices.
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Ferromagnet/heavy metal bilayers represent a central building block for spintronic devices where the magnetization of the ferromagnet can be controlled by spin currents generated in the heavy metal. The efficiency of spin current generation is paramount. Equally important is the efficient transfer of this spin current across the ferromagnet/heavy metal interface. Here, we show theoretically and experimentally that for Ta as heavy metal the interface only partially transmits the spin current while this effect is absent when Pt is used as heavy metal. This is due to magnetic moment reduction at the interface caused by 3d-5d hybridization effects. We show that this effect can be avoided by atomically thin interlayers. On the basis of our theoretical model we conclude that this is a general effect and occurs for all 5d metals with less than half-filled 5d shell.
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BACKGROUND: The main objective of this study was the validation through the expert judgment of the first Spanish version of the Eppendorf Schizophrenia Inventory (ESI-Sp). MATERIALS AND METHODS: A translation and cultural adaptation procedure as a first stage was carried out, which was evaluated by four psychiatrists with clinical experience. In a second stage, we recruited a group of clinical psychiatrists to evaluate the translated instrument by judging the items' clarity and relevance. Content validity was performed using the Aiken methodology (Aiken's V). RESULTS: For the first stage, we did not find any items that needed alteration during translation and adaptation. Concerning the raters' stage, 30 clinical psychiatrists (47.07±13.62 years) completed the rating of the ESI-Sp. Of them, the majority worked in an institute (10/30; 33.33%) and had "15 or more" years of experience (12/30; 40.00%). The null hypothesis was rejected for all items and demonstrated the content validity of each item. Similar results were found for the factors of the ESI. Finally, the total Aiken's V for the ESI did not include the values of the null hypothesis in the confidence intervals (V=0.78; CI95 [0.70; 0.85]), demonstrating content validity. CONCLUSIONS: ESI-Sp is a valid and representative instrument to determine subjective experiences in patients with a high risk of schizophrenia. The construct validation of the ESI-Sp is pending, which our research group will carry out after this first step.
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RESUMEN Objetivo Describir las tendencias de la frecuencia de obesidad y su relación con algunos factores socioeconómicos en mujeres en edad fértil en el Perú. Material y métodos Estudio transversal de datos secundarios, analítico utilizando las bases de datos de la Encuesta Nacional Demográfica en Salud (ENDES) de los años 2005 a 2018. Se estimó la frecuencia de mujeres con obesidad para cada año y se las comparó mediante los intervalos de confianza al 95% (IC95%). Se comparó la magnitud de asociación de lugar, edad y paridad, lugar de residencia, grado de educación e índice de riqueza. Resultados Se observó un aumento de la obesidad en mujeres en edad fértil de 17,72% (IC95%: 16,24-19,32) en el 2005 a 32% (IC95%: 30,46-34,42) en el 2018. La prevalencia de obesidad tipo I aumentó de 9,07% (IC95% 8,09-10,16) en el año 2005 a 22,15% (IC95% 15,19-16,48) en el 2018. Se observó un aumento continuo en la prevalencia de obesidad tipo II de 2,34% (IC95% 1,84-3,05) a 7,29% (IC95% 3,75-4,52). En las mujeres que se encontraron embarazadas al momento de la entrevista se encontró una prevalencia de obesidad de 17,21% (IC95% 11,42-25,10) en el año 2005 llegando a 38,61% (IC95% 20,25-28,46) en el año 2018. Se encontró relación significativa de la posibilidad de ser obesa con la edad y la paridad. Conclusiones La prevalencia de obesidad en las mujeres en edad fértil en nuestro país es alta y continúa incrementando con el tiempo. La prevalencia incrementada se presenta igualmente en gestantes, incrementando las complicaciones materno-perinatales.
SUMMARY Objective To describe the trends in the frequency of obesity and its relationship with some socioeconomic factors in women of childbearing age in Peru. Methods Analytical cross-sectional study of secondary data, using the databases of the Encuesta Nacional Demográfica en Salud (ENDES) from 2005 to 2018. The frequency of women with obesity was estimated for each year and compared using the confidence intervals at 95% (95% CI). The magnitude of association was compared between place, age and parity, place of residence, level of education and wealth index. Results An increase in obesity was observed in women of childbearing age from 17.72% (95% CI: 16.24-19.32) in 2005 to 32% (95% CI: 30.46-34.42) in 2018. The prevalence of type I obesity increased from 9.07% (95% CI 8.09-10.16) in 2005 to 22.15% (95% CI 15.19-16.48) in 2018. It was observed a continuous increase in the prevalence of type II obesity from 2.34% (95% CI 1.84-3.05) to 7.29% (95% CI 3.75-4.52). In women who were pregnant at the time of the interview, a prevalence of obesity was found to be 17.21% (95% CI 11.42-25.10) in 2005, reaching 38.61% (95% CI 20.25). -28.46) in 2018. A significant relationship was found between the possibility of being obese with age and parity. Conclusions The prevalence of obesity in women of childbearing age in our country is high and continues to increase over time. The increased prevalence also occurs in pregnant women, increasing maternal-perinatal complications.
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Canal curvatures of 700 permanent human teeth were determined by measuring the angle and the radius of the curvatures and the length of the curved part of the canal. For each type of tooth (except third molars) 50 were selected at random and were investigated. Size 08 silver points were inserted into the canals, and the teeth were radiographed from a facial and proximal view by using a standardized technique. All radiographs were analyzed by a computerized digital image processing system. Of the 1163 root canals examined, 980 (84%) were curved and 65% showed an angle < or = 27 degrees with radii < 40 mm. Thirteen percent displayed angles between 27 degrees and 35 degrees with radii not greater than 15 mm, and 9% of all canals that were investigated had curves > 35 degrees with the greatest radius of 13 mm. The greatest angle of all the teeth was 75 degrees with a radius of 2 mm. To define the canal curvature mathematically and unambiguously, the angle, the radius, and the length of the curve should be given.