Broadband transverse susceptibility in multiferroic Y-type hexaferrite Ba0.5Sr1.5Zn2Fe12O22

Producción CientíficaNoncollinear spin systems with magnetically induced ferroelectricity from changes in spiral magnetic ordering have attracted significant interest in recent research due to their remarkable magnetoelectric effects with promising applications. Single phase multiferroics are of great interest for these new multifunctional devices, being Y-type hexaferrites good candidates, and among them the ZnY compounds due to their ordered magnetic behaviour over room temperature. Polycrystalline Y type hexaferrites with composition Ba0.5Sr1.5Zn2Fe2O22 (BSZFO) were sintered in 1050 °C–1250 °C temperature range. Transverse susceptibility measurements carried out on these BSZFO samples in the temperature range 80–350 K with DC fields up to ± 5000 Oe reveal different behaviour depending on the sintering temperature. Sample sintered at 1250 °C is qualitatively different, suggesting a mixed Y and Z phase like CoY hexaferrites. Sintering at lower temperatures produce single phase Y-type, but the transverse susceptibility behaviour of the sample sintered at 1150 °C is shifted at temperatures 15 K higher. Regarding the DC field sweeps the observed behaviour is a peak that shifts to lower values with increasing temperature, and the samples corresponding to single Y phase exhibit several maxima and minima in the 250 K–330 K range at low DC applied field as a result of the magnetic field induced spin transitions in this compound.Ministerio de Ciencia, Innovación y Universidades; Agencia Estatal de Investigación with FEDER (MAT2016-80784-P

Formación docente constante para una comunicación virtual efectiva

El presente ensayo se basa en el supuesto que “La Formación Docente debe ser constante y efectiva en la Comunicación Virtual”. En la actualidad los profesionales de la educación deben manejar una comunicación efectiva, pues la enseñanza expuesta a constantes cambios debe garantizar la enseñanza y aprendizaje haciendo uso de las tecnologías, al mismo tiempo que el profesorado debe actualizar sus conocimientos de forma dinámica y en constante cambio. Los docentes hoy son protagonistas de un cambio profundo en las metodologías educativas y para ello requieren de capacitaciones progresivas, las plataformas online educativas tecnológicas nos invitan a la innovación pedagógica y acercamiento a las nuevas generaciones de estudiantes, en consecuencia, las clases presenciales deben ser transformadas a la virtualidad con cambios profundos de formatos educativos, para que el educando participe de su aprendizaje Virtual

Prym varieties, curves with automorphisms and the Sato Grassmannian

Este trabajo trata las variedades de Prym, curvas con automorfismos y Grassmannian de Sato.The aim of the paper is twofold. First, some results of Shiota and Plaza-Martín on Prym varieties of curves with an involution are generalized to the general case of an arbitrary automorphism of prime order. Second, the equations defining the moduli space of curves with an automorphism of prime order as a subscheme of the Sato Grassmannian are given

E-status: a web tool for learning by doing exercises

The paper introduces the project led by a team of teachers to assist students learn statistics. The goal is to build a tool able to present mathematical problems and to correct the students´ answers. The problems may include random data, so the solution cannot be previously known (if solved before) and the student can reconsider it if necessary. Pedagogical implications are commented, since the method can be effective on the basic and middle domains of learning, as well as on higher levels, specially if careful design of the problems is applied.Postprint (published version

Wnt and vitamin D at the crossroads in solid cancer

The Wnt/β-catenin signaling pathway is aberrantly activated in most colorectal cancers and less frequently in a variety of other solid neoplasias. Many epidemiological and experimental studies and some clinical trials suggest an anticancer action of vitamin D, mainly against colorectal cancer. The aim of this review was to analyze the literature supporting the interference of Wnt/β-catenin signaling by the active vitamin D metabolite 1α,25-dihydroxyvitamin D3. We discuss the molecular mechanisms of this antagonism in colorectal cancer and other cancer types. Additionally, we summarize the available data indicating a reciprocal inhibition of vitamin D action by the activated Wnt/β-catenin pathway. Thus, a complex mutual antagonism between Wnt/β-catenin signaling and the vitamin D system seems to be at the root of many solid cancers. Abnormal activation of the Wnt/β-catenin pathway is common in many types of solid cancers. Likewise, a large proportion of cancer patients have vitamin D deficiency. In line with these observations, Wnt/β-catenin signaling and 1α,25-dihydroxyvitamin D3 (1,25(OH)2D3), the active vitamin D metabolite, usually have opposite effects on cancer cell proliferation and phenotype. In recent years, an increasing number of studies performed in a variety of cancer types have revealed a complex crosstalk between Wnt/β-catenin signaling and 1,25(OH)2D3. Here we review the mechanisms by which 1,25(OH)2D3 inhibits Wnt/β-catenin signaling and, conversely, how the activated Wnt/β-catenin pathway may abrogate vitamin D action. The available data suggest that interaction between Wnt/β-catenin signaling and the vitamin D system is at the crossroads in solid cancers and may have therapeutic applications.The work in the authors’ laboratory is funded by the Agencia Estatal de Investigación (PID2019-104867RB-I00/AEI/10.13039/501100011033), the Agencia Estatal de Investigación—Fondo Europeo de Desarrollo Regional (SAF2016-76377-R, MINECO/AEI/FEDER, EU), the Ministerio de Economía y Competitividad (SAF2017-90604-REDT/NuRCaMeIn), and the Instituto de Salud Carlos III—Fondo Europeo de Desarrollo Regional (CIBERONC; CB16/12/00273

Influencia del consumo moderado de cerveza sobre la toxicocinética del aluminio: estudio agudo

Objective: Aluminium has lately been implicated as one of the possible causal factors contributing to Alzheimer's disease and other neurodegenerative disorders due to this metal is conducive to oxidative stress in the brain. According to different researches, it has been suggested that silicon may interfere in the toxico-kinetic of this metal. The present study has examined the effect of beer consumption as a source of silicon on the bioavailability of aluminium and the possible role of beer consumption in averting aluminium's neurotoxicity. Material and methods: In a three-day study, male rats were subjected to acute exposure to aluminium while being given two types of beer, i.e., alcoholic and non-alcoholic beer, to drink at two intake levels, one equivalent to moderate to low consumption in humans (0.5 I/d; 27.5 g alcohol/d) and another equivalent to moderate to high consumption in humans (1 I/d; 55 g alcohol/day). Aluminium and silicon were determined by ICP-MS and ICPOES, respectively. Results: The results obtained seem indicate that at moderately high levels of alcoholic beer intake the silicon present in the beer was able to reduce aluminium uptake in the digestive tract, increasing its excretion by faecal route. In addition, a possible interaction of both elements at level of distribution and renal excretion is suggested. Conclusion: In consequence, moderate beer consumption, possibly affording a protective factor for the toxic effect of aluminium, one of the environmental factors for Alzheimer's disease

Factores que influyen para que el paciente con hipertensión no modifique sus estilos de vida

La Hipertensión Arterial es la enfermedad más frecuente que afecta a millones de personas en el mundo. Entre los factores predisponentes de la presencia de Hipertensión son los estilos de vida no saludables, la edad y la herencia

Monitoring heavy metal contents in food and hair in a sample of young Spanish subjects

For most people the main route Of exposure to the toxic elements is through the diet. Consequently, information concerning dietary intake is of the utmost importance in being able to assess risks to human health. The goal of this study was to intend to assess the usefulness of hair as a biomonitor of the mineral status in young adults. Daily intakes of selected toxic and essential mineral elements were evaluated using a food frequency questionnaire. In addition, the levels of these same elements in hair samples were Measured by inductively Coupled plasma mass spectrometry and inductively coupled plasma atomic emission spectrometry. The contents of the essential elements in the study population were all well above Spanish recommendations for adult males and females. The estimated intakes of toxic elements were appreciably below the respective PTWIs, indicating that these intake levels do not pose a health concern for this group. Significant differences in hair metal levels were observed between the men and the women, who were in the same age group. Interestingly, no correlation was found between trace element intakes and the corresponding levels in the hair. In conclusion, hair is only limited usefulness as a means of estimating the nutritional status of the essential and toxic elements considered

Role of beer as a possible protective factor in preventing Alzheimer's disease

Aluminium (Al), a neurotoxin, has lately been implicated as one of the possible causal factors contributing to Alzheimer's disease. Because silicon (Si) intake can affect the bioavailability of aluminium, the object of the present study was to assess whether moderate beer consumption might, as a source of dietary Si, affect the toxicokinetics of Al and thereby limit that element's neurotoxicity. The results obtained confirmed that at moderately high levels of beer intake the Si present in the beer was able to reduce Al uptake in the digestive tract and thus was able to slow the accumulation of this metal in the body, brain tissue included. In consequence, moderate beer consumption, due to its content in bioavailability silicon, possibly affording a protective factor for preventing Alzheimer's disease, could perhaps be taken into account as a component of the dietary habits of the population