Localization and oscillations of Majorana fermions in a two-dimensional electron gas coupled with d-wave superconductors

We study the localization and oscillation properties of the Majorana fermions that arise in a two-dimensional electron gas (2DEG) with spin-orbit coupling (SOC) and a Zeeman field coupled with a d-wave superconductor. Despite the angular dependence of the d-wave pairing, localization and oscillation properties are found to be similar to the ones seen in conventional s-wave superconductors. In addition, we study a microscopic lattice version of the previous system that can be characterized by a topological invariant. We derive its real space representation that involves nearest and next-to-nearest-neighbors pairing. Finally, we show that the emerging chiral Majorana fermions are indeed robust against static disorder. This analysis has potential applications to quantum simulations and experiments in high-T_(c) superconductors

Application of Biochar for the Restoration of Metal(loid)s Contaminated Soils

Funding: The work has been supported by funds from the Spanish Ministry of Economy, Industry and Competitiveness through the Project “CTM2017-86504-R”, and by Ministry of Science, Innovation and Universitiesam trought Research Project “RTI2018-094327-B-I00”.Biochar has recently aroused great interest for the restoration of contaminated soils since it improves soil properties and induces the immobilization of pollutants. This study evaluates the use of biochar from plant pruning, applied as an amendment, for immobilizing metal(loid)s in a highly contaminated soil as well as for reducing the phytotoxicity of these pollutants by promoting natural revegetation. For this purpose, a bioassay with Trifolium pratense L. was used to test the effectiveness of the soil amendment in greenhouse conditions. Three treatments were carried out including soil contaminated with metal(loid)s (RA), and this soil was amended with biochar at different dosage: 4% (RA4B) and 8% (RA8B). A non-contaminated soil (NC) from a nearby area not affected by contamination was used as a control. The results show that biochar increased soil pH by several units depending on the dose used, 8% being the most effective one. Biochar treatments also reduced soluble and bioavailable forms of Zn and Cu. Likewise, phytotoxicity was significantly reduced, promoting seed germination and biomass with plant growth values similar to the non-polluted soil. In light of the results obtained, the evaluation of the bioremediation potential of biochar under field conditions can be considered.Ministry of Science, Innovation and Universitiesam trought Research Project RTI2018-094327-B-I00Ministerio de Economía, Industria y Competitividad, Gobierno de España CTM2017-86504-

Application of biochar for the restoration of metal(loid)s contaminated soils

Biochar has recently aroused great interest for the restoration of contaminated soils since it improves soil properties and induces the immobilization of pollutants. This study evaluates the use of biochar from plant pruning, applied as an amendment, for immobilizing metal(loid)s in a highly contaminated soil as well as for reducing the phytotoxicity of these pollutants by promoting natural revegetation. For this purpose, a bioassay with Trifolium pratense L. was used to test the effectiveness of the soil amendment in greenhouse conditions. Three treatments were carried out including soil contaminated with metal(loid)s (RA), and this soil was amended with biochar at different dosage: 4% (RA4B) and 8% (RA8B). A non-contaminated soil (NC) from a nearby area not affected by contamination was used as a control. The results show that biochar increased soil pH by several units depending on the dose used, 8% being the most effective one. Biochar treatments also reduced soluble and bioavailable forms of Zn and Cu. Likewise, phytotoxicity was significantly reduced, promoting seed germination and biomass with plant growth values similar to the nonpolluted soil. In light of the results obtained, the evaluation of the bioremediation potential of biochar under field conditions can be considere

Sentidos construidos por los docentes en torno a las trayectorias educativas en los primeros años de la escuela secundaria técnica

El propósito de este proyecto de investigación es comprender aquellos ´sentidos´ que los docentes construyen sobre sus prácticas de enseñanza en primero y segundo año, en establecimientos de educación secundaria de modalidad técnico-profesional, y que pueden incidir en la permanencia de los estudiantes de ese nivel. El dato que lleva a indagar se sustenta en que el mayor abandono y repitencia se ubica en los primeros años y se agrava en establecimientos de modalidad técnico-profesional. Por ello es de interés realizar el abordaje en una escuela de la ciudad de Bariloche, localizada en uno de los barrios, denominados “del alto”. A ella asisten jóvenes que en varios casos, son primeras generaciones en el nivel, pertenecientes algunos, a poblaciones migrantes de los pueblos originarios del territorio argentino-chileno. De este modo se busca problematizar aquellos saberes socialmente sedimentados, recuperando los aportes de la Filosofía de la Educación, desde su mirada deconstructiva, analítica y desnaturalizadora, de la práctica educativa, en torno a las ´trayectorias´ educativas en los primeros años de la escuela técnica secundaria. Como así también, abordar aquellos aspectos socio-culturales que se despliegan en el encuentro docente-s estudiante-s; desde un enfoque etnográfico, que permite la reflexión y el análisis de los sentidos construidos en la práctica docente.Mesa 40: Sociología de la experiencia escolar. Formatos, vínculos y procesos de desigualdad en la escuela secundariaFacultad de Humanidades y Ciencias de la Educació

Sentidos construidos por los docentes en torno a las trayectorias educativas en los primeros años de la escuela secundaria técnica

El propósito de este proyecto de investigación es comprender aquellos ´sentidos´ que los docentes construyen sobre sus prácticas de enseñanza en primero y segundo año, en establecimientos de educación secundaria de modalidad técnico-profesional, y que pueden incidir en la permanencia de los estudiantes de ese nivel. El dato que lleva a indagar se sustenta en que el mayor abandono y repitencia se ubica en los primeros años y se agrava en establecimientos de modalidad técnico-profesional. Por ello es de interés realizar el abordaje en una escuela de la ciudad de Bariloche, localizada en uno de los barrios, denominados “del alto”. A ella asisten jóvenes que en varios casos, son primeras generaciones en el nivel, pertenecientes algunos, a poblaciones migrantes de los pueblos originarios del territorio argentino-chileno. De este modo se busca problematizar aquellos saberes socialmente sedimentados, recuperando los aportes de la Filosofía de la Educación, desde su mirada deconstructiva, analítica y desnaturalizadora, de la práctica educativa, en torno a las ´trayectorias´ educativas en los primeros años de la escuela técnica secundaria. Como así también, abordar aquellos aspectos socio-culturales que se despliegan en el encuentro docente-s estudiante-s; desde un enfoque etnográfico, que permite la reflexión y el análisis de los sentidos construidos en la práctica docente.Mesa 40: Sociología de la experiencia escolar. Formatos, vínculos y procesos de desigualdad en la escuela secundariaFacultad de Humanidades y Ciencias de la Educació

Inhibition of PTEN by peroxynitrite activates the phosphoinositide-3-kinase/Akt neuroprotective signaling pathway

El derivado del óxido nítrico, peroxinitrito, activa una cascada de señalización de supervivencia en neuronas. El mecanismo implica la oxidación de la fosfatasa PTEN, que permite incrementar la forma fosforilada (neuroprotectora) de akt.Peroxynitrite is usually considered as a neurotoxic nitric oxidederivative. However, an increasing body of evidence suggests that, at low concentrations, peroxynitrite affords transient cytoprotection, both in vitro and in vivo. Here, we addressed the signaling mechanism responsible for this effect, and found that rat cortical neurons in primary culture acutely exposed to peroxynitrite (0.1 mmol/L) rapidly elicited Akt-Ser473 phosphorylation. Inhibition of phosphoinositide-3-kinase (PI3K)/Akt pathway with wortmannin or Akt small hairpin RNA (shRNA) abolished the ability of peroxynitrite to prevent etoposide-induced apoptotic death. Endogenous peroxynitrite formation by short-term incubation of neurons with glutamate stimulated Akt-Ser473 phosphorylation, whereas Akt shRNA enhanced the vulnerability of neurons against glutamate. We further show that Akt-Ser473 phosphorylation was consequence of the oxidizing, but not the nitrating properties of peroxynitrite. Peroxynitrite failed to nitrate or phosphorylate neurotrophin tyrosine kinase receptors (Trks), and it did not modify the ability of brain-derived neurotrophic factor (BDNF), to phosphorylate its cognate receptor, TrkB; however, peroxynitrite enhanced BDNF-mediated Akt-Ser473 phosphorylation. Finally, we found that peroxynitrite-stimulated Akt-Ser473 phosphorylation was associated with an increased proportion of oxidized phosphoinositide phosphatase, PTEN, in neurons. Moreover, peroxynitrite prevented the increase of apoptotic neuronal death caused by over-expression of PTEN. Thus, peroxynitrite exerts neuroprotection by inhibiting PTEN, hence activating the anti-apoptotic PI3K/Akt pathway in primary neurons

Presencia de diferentes formas de estimación en el currículo de educación primaria

La estimación es una componente clave de la competencia matemática y una habilidad fundamental para la vida cotidiana. Adoptamos una amplia concepción de este término que incluye cinco formas de estimación. Tres de ellas han sido consideradas tradicionalmente en la literatura: la estimación en cálculo, la estimación de cantidades (o de magnitudes discretas) y la estimación en la medida (o de magnitudes continuas). La estimación en la recta numérica es referida recientemente en la literatura como una forma de estimación que actúa de predictor del rendimiento en matemáticas a lo largo de la educación obligatoria y de posteriores dificultades en el aprendizaje de las matemáticas. Además, reconocemos una quinta acepción relativa a contextos probabilísticos. Desde este enfoque múltiple, realizamos un análisis de la presencia de la estimación en el currículo de educación primaria español

Comprensión del concepto de serie numérica a través del modelo de Pirie y Kieren

Diversas investigaciones han dado cuenta de las dificultades que tienen los estudiantes para la adquisición y comprensión del concepto de serie numérica. Los conceptos de límite e infinito, así como la diferenciación entre la serie y la sucesión de sumas parciales, son algunos de los obstáculos que han de superar. En este artículo, se analiza el proceso que sigue un grupo de estudiantes cuando resuelve una actividad sobre el cálculo de la altura y el volumen de una torre que involucra el trabajo con series armónicas mediante el modelo de Pirie y Kieren. Comenzando desde el nivel Image Making, los alumnos realizan conexiones entre diferentes elementos matemáticos del concepto de serie numérica. Las interacciones entre ellos les permiten avanzar entre los diferentes niveles del modelo para lograr la comprensión del concepto recurriendo al mecanismo de folding back.Several research studies have realized the difficulties faced by students for the acquisition and understanding of the concept of numerical series. The concepts of limits, infinity and the difference between the series and the sequence of partial sums are some obstacles to be overcome. This article analyzes the process that follows a group of students solving the activity about the calculi of the height and volume of a tower that involves working with harmonic series in the light of Pirie and Kieren model. Starting from Image Making level the students link different elements of the mathematical concept of numerical series. The interactions between them allow to advance between the different levels of the model to develop an understanding of the concept using the folding back mechanism

https://doi.org/10.1016/j.chemosphere.2023.140364

The fate of the antibiotic sulfamethoxazole in amended soils remains unclear, moreover in basic soils. This work aimed to assess the adsorption, leaching, and biodegradation of sulfamethoxazole in unamended and biochar from holm oak pruning (BC)- and green compost from urban pruning (CG)-amended basic soil. Adsorption properties of the organic amendments and soil were determined by adsorption isotherms of sulfamethoxazole. The leachability of this antibiotic from unamended (Soil) and BC- (Soil + BC) and GC- (Soil + GC) amended soil was determined by leaching columns using water as solvent up to 250 mL. Finally, Soil, Soil + BC, and Soil + GC were spiked with sulfamethoxazole and incubated for 42 days. The degradation rate and microbial activity were periodically monitored. Adsorption isotherms showed poor adsorption of sulfamethoxazole in unamended basic soil. BC and CG showed good adsorption capacity. Soil + BC and Soil + GC increased the sulfamethoxazole adsorption capacity of the soil. The low sulfamethoxazole adsorption of Soil produced quick and intense sulfamethoxazole leaching. Soil + BC reduced the sulfamethoxazole leaching, unlike to Soil + GC which enhanced it concerning Soil. The pH of adsorption isotherms and leachates indicate that the anion of sulfamethoxazole was the major specie in unamended and amended soil. CG enhanced the microbial activity of the soil and promoted the degradability of sulfamethoxazole. In contrast, the high adsorption and low biostimulation effect of BC in soil reduced the degradation of sulfamethoxazole. The half-life of sulfamethoxazole was 2.6, 6.9, and 11.9 days for Soil + GC, Soil, and Soil + BC, respectively. This work shows the benefits and risks of two organic amendments, BC and GC, for the environmental fate of sulfamethoxazole. The different nature of the organic carbon of the amendments was responsible for the different effects on the soilPDC 2021-120744-I0

Topological phases in nodeless tetragonal superconductors

We compute the topological phase diagram of 2D tetragonal superconductors for the only possible nodeless pairing channels compatible with that crystal symmetry. Subject to a Zeeman field and spin-orbit coupling, we demonstrate that these superconductors show surprising topological features: non-trivial high Chern numbers, massive edge states, and zero-energy modes out of high symmetry points, even though the edge states remain topologically protected. Interestingly, one of these pairing symmetries, d + id, has been proposed to describe materials such as water-intercalated sodium cobaltates, bilayer silicene or highly doped monolayer graphene