Spin separation in digital ferromagnetic heterostructures

In a study of the ferromagnetic phase of a multilayer digital ferromagnetic semiconductor in the mean-field and effective-mass approximations, we find the exchange interaction to have the dominant energy scale of the problem, effectively controlling the spatial distribution of the carrier spins in the digital ferromagnetic heterostructures. In the ferromagnetic phase, the majority and minority carriers tend to be in different regions of the space (spin separation). Hence, the charge distribution of carriers also changes noticeably from the ferromagnetic to the paramagnetic phase. An example of a design to exploit these phenomena is given.Comment: 4 pages, 3 figures. Submitted to Phys. Rev.

Electromodulation of the Magnetoresistance in Diluted Magnetic Semiconductors Based Heterostructures

We study the properties of heterostructures formed by two layers of diluted magnetic semiconductor separated by a nonmagnetic semiconductor layer. We find that there is a RKKY-type exchange coupling between the magnetic layers that oscilles between ferromagnetic and antiferromagnetic as a function of the different parameters in the problem. The different transport properties of these phases make that this heterostructure presents strong magnetoresistive effects. The coupling can be also modified by an electric field. We propose that it is possible to alter dramatically the electrical resistance of the heterostructure by applying an electric field. Our results indicate that in a single gated sample the magnetoresistance could be modulated by with an electrical bias voltage.Comment: 4 pages, 5 figures include

El perfil de los inversores y las entidades financieras: una aproximación desde el entorno de la economía social

Este trabajo pretende presentar un análisis, de los resultados de perfiles de ahorro e inversión de la familia española, específicamente, de aquellas familias que han optado por los servicios financieros ofrecidos por las cajas de ahorros y las cooperativas de crédito, al, entre otros, financiar la compra de la vivienda principal, financiar la compra de otros inmuebles, adquirir créditos de consumo, contratar activos financieros y contratar seguros o planes de pensiones. A través de un análisis de conglomerados, efectuado sobre los datos publicados en 2006de La Encuesta Financiera de las Familias Españolas, realizada a familias de cuatro estratos de riqueza diferentes, distribuidas en todas las comunidades del país, llevada a cabo en el año 2002 por el Banco de España, se hallan y se describen en esta investigación, las principales características demográficas y de la estructura financiera de 687 familias, que de un total de 5143, han preferido y efectivamente seleccionado a las cooperativas de crédito o a las cajas de ahorro, como proveedoras de los más básicos servicios financieros.This paper aims to present an analysis of the saving and investment profiles of the Spanish family, more specifically, those families who have opted for the financial services offered by savings and credit cooperatives in order to finance the purchase of a primary residence or other property, acquire consumer credit, purchase financial assets or acquire insurance or pension plans. Through a cluster analysis performed on the data published in The Financial Survey of Spanish Families in 2006, which surveyed families of four different wealth strata throughout the country, conducted in 2002 by the Bank of Spain, this research describes the main demographic characteristics and financial structures of the 687 families, of a total of 5143, that actually preferred credit unions or savings banks as their providers of basic financial services

The incidence of cancer in patients with rheumatoid arthritis and a prior malignancy who receive TNF inhibitors or rituximab: results from the British Society for Rheumatology Biologics Register-Rheumatoid Arthritis

Objective. To explore the influence of TNF inhibitor (TNFi) therapy and rituximab (RTX) upon the incidence of cancer in patients with RA and prior malignancy. Methods. The study population comprised RA subjects with a prior malignancy reported to the UK national cancer registers, recruited to the British Society for Rheumatology Biologics Register from 2001 to 2013. We compared rates of first incident malignancy in a TNFi cohort, RTX cohort and synthetic DMARDs (sDMARD) cohort. Results. We identified 425 patients with a prior malignancy from 18 000 RA patients in the study. Of these, 101 patients developed a new malignancy. The rates of incident malignancy were 33.3 events/1000 person-years (py) in the TNFi cohort, 24.7 events/1000 py in the RTX cohort and 53.8 events/1000 py in the sDMARD cohort. The age- and gender-adjusted hazard ratio was 0.55 (95% CI: 0.35, 0.86) for the TNFi cohort and 0.43 (95% CI: 0.10, 1.80) for the RTX cohort in comparison with the sDMARDs cohort. The 17.0% of patients in the sDMARDs cohort had a recurrence of the same cancer in comparison with the 12.8% and the 4.3% in the TNFi and RTX cohorts, respectively. Conclusions. Although numbers are still low, it seems that patients with RA and prior malignancy selected to receive either a TNFi or RTX in the UK do not have an increased risk of future incident malignancy

End-on PEGylation of heparin: Effect on anticoagulant activity and complexation with protamine

Supplementary data to this article can be found online at https://doi.org/10.1016/j.ijbiomac.2023.125957.Heparin is the most common anticoagulant used in clinical practice but shows some downsides such as short half- life (for the high molecular weight heparin) and secondary effects. On the other hand, its low molecular weight analogue cannot be neutralized with protamine, and therefore cannot be used in some treatments. To address these issues, we conjugated polyethylene glycol (PEG) to heparin reducing end (end-on) via oxime ligation and studied the interactions of the conjugate (Hep-b-PEG) with antithrombin III (AT) and protamine. Isothermal titration calorimetry showed that Hep-b-PEG maintains the affinity to AT. Dynamic light scattering demonstrated that the Hep-b-PEG formed colloidal stable nanocomplexes with protamine instead of large multi-molecular aggregates, associated with heparin side effects. The in vitro (human plasma) and in vivo experiments (Sprague Dawley rats) evidenced an extended half-life and higher anticoagulant activity of the conjugate when compared to unmodified heparin.  The authors thank INNO Laboratório Veterinário for the measurements of in vivo coagulation times, Raul Pacheco for discussions about the ITC results, Teresa Oliveira for her help in the in vivo experiments and Ramón Rail for his help in the 3D structures of Fig. 1, Fig. 4. We thank funding provided by the Portuguese Foundation for Science and Technology (PTDC/QUI-POL/28117/2017 and CEECIND/00814/2017). África González-Fernández thanks Xunta de Galicia (Grupo de Referencia competitiva, GRC-ED431C 2020/02) 2020-2023

Characterization of broadband few-cycle laser pulses with the d-scan technique.

[EN]We present an analysis and demonstration of few-cycle ultrashort laser pulse characterization using second-harmonic dispersion scans and numerical phase retrieval algorithms. The sensitivity and robustness of this technique with respect to noise, measurement bandwidth and complexity of the measured pulses is discussed through numerical examples and experimental results. Using this technique, we successfully demonstrate the characterization of few-cycle pulses with complex and structured spectra generated from a broadband ultrafast laser oscillator and a high-energy hollow fiber compressor

Shallow structure beneath the Central Volcanic Complex of Tenerife from new gravity data: implications for its evolution and recent reactivation

We present a new local Bouguer anomaly map of the Central Volcanic Complex (CVC) of Tenerife, Spain, constructed from the amalgamation of 323 new high precision gravity measurements with existing gravity data from 361 observations. The new anomaly map images the high-density core of the CVC and the pronounced gravity low centred in the Las Cañadas caldera in greater detail than previously available. Mathematical construction of a sub-surface model from the local anomaly data, employing a 3D inversion based on 'growing' the sub-surface density distribution via the aggregation of cells, enables mapping of the shallow structure beneath the complex, giving unprecedented insights into the sub-surface architecture. We find the resultant density distribution in agreement with geological and other geophysical data. The modelled sub-surface structure supports a vertical collapse origin of the caldera, and maps the headwall of the ca. 180 ka Icod landslide, which appears to lie buried beneath the Pico Viejo–Pico Teide stratovolcanic complex. The results allow us to put into context the recorded ground deformation and gravity changes at the CVC during its reactivation in spring 2004 in relation to its dominant structural building blocks. For example, the areas undergoing the most significant changes at depth in recent years are underlain by low-density material and are aligned along long-standing structural entities, which have shaped this volcanic ocean island over the past few million years

Biotic homogenization of oceanic islands depends on taxon, spatial scale and the quantification approach

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