Differential equations with natural matrices coefficients

In this paper we present the main results of the master thesis in applied mathematics of the second named author, which was supervised by the first named author. Such results, and for instance this paper, concerns to some differential and algebraic results involving natural matrices. The problem of solving differential equations is very ancient and is very important to get explicit solutions of differential equations to be applied in physics and other areas. In this paper, as well in the master thesis, we study the differential and algebraic structure of linear differential equations with natural matrix coefficients and generalizations. These results are original and important for researchers interested in differential algebra and applications of differential equations

Dos analogías en la enseñanza del concepto de modelo científico: Análisis de las observaciones de clase

Enseñar sobre la naturaleza de los modelos científicos, como parte de la naturaleza de las ciencias, es un objetivo prioritario reconocido en la enseñanza. El propósito de este trabajo es verificar la eficacia de una propuesta didáctica basada en el uso de analogías para comprender el concepto de modelo científico. Se presenta el diseño de investigación llevado adelante con alumnos futuros maestros que incluye el empleo de dos analogías: la caja negra y los mapas. Ambas analogías fueron enriquecidas con respecto a lo que se encuentra desarrollado en la bibliografía. En este trabajo se muestran los aprendizajes de los alumnos, en términos cualitativos, analizados a partir de observaciones de clase y de un informe de autoevaluación. Se comprobó que esta propuesta constituyó un avance en la comprensión del concepto de modelo y modelado en ciencias así como también de la naturaleza de las analogías como recurso pedagógico

Density-Temperature-Softness Scaling of the Dynamics of Glass-forming Soft-sphere Liquids

The principle of dynamic equivalence between soft-sphere and hard-sphere fluids [Phys. Rev. E \textbf{68}, 011405 (2003)] is employed to describe the interplay of the effects of varying the density n, the temperature T, and the softness (characterized by a softness parameter {\nu}^{-1}) on the dynamics of glass-forming soft-sphere liquids in terms of simple scaling rules. The main prediction is that the dynamic parameters of these systems, such as the {\alpha}-relaxation time and the long-time self-diffusion coefficient, depend on n, T, and {\nu} only through the reduced density n^\ast \equiv n{\sigma}^{3}_{HS}(T, {\nu}),where the effective hard-sphere diameter {\sigma}_{HS}(T, {\nu}) is determined, for example, by the Andersen-Weeks-Chandler condition for soft-sphere-hard-sphere structural equivalence. A number of scaling properties observed in recent simulations involving glass-forming fluids with repulsive short range interactions are found to be a direct manifestation of this general dynamic equivalence principle. The self-consistent generalized Langevin equation (SCGLE) theory of colloid dynamics is shown to accurately capture these scaling rule

Uretroplastia de sustitución con doble injerto de mucosa oral como opción terapéutica para pacientes con estenosis de uretra bulbar asociada a UroLume®

ResumenEl UroLume® o endoprótesis uretral fue concebido como un dispositivo de fácil colocación para pacientes con estenosis uretral bulbar recurrente. Con el paso del tiempo se demostró que ocasionaba más complicaciones que beneficios por lo que se abandonó su uso. Sin embargo, se generó un grupo de pacientes con estenosis uretral compleja que necesitaban múltiples tratamientos quirúrgicos con resultados poco favorecedores. Con la divulgación a finales de la década de los 90 del uso de injertos de mucosa oral para el tratamiento de estenosis uretral se inició una nueva etapa en la búsqueda de un tratamiento definitivo para este tipo de pacientes. El objetivo del artículo es presentar una técnica quirúrgica no descrita en la literatura para el tratamiento de estenosis uretral bulbar asociada a UroLume®. Se describe el caso de un paciente masculino de 71 años de edad con estenosis uretral bulbar secundaria a resección transuretral de próstata al cual le fue colocado un UroLume® hace 8 años presentando reestenosis uretral, tratado con múltiples dilataciones uretrales. Mediante un abordaje perineal se retiró la endoprótesis en su totalidad, en base a las características locales de los tejidos se decidió colocar un doble injerto de mucosa oral dorsal inlay y ventral onlay con resultados exitosos a 6 meses de seguimiento.AbstractUroLume®, or urethral endoprosthesis, was conceived as an easy placement device for patients with recurrent bulbar urethral stricture. With the passage of time, it was shown to cause more complications than benefits and its use was discontinued. However, it created a group of patients with complex urethral stricture that required multiple surgical treatments with unsatisfactory results. The widespread use at the end of the 1990s of buccal mucosa grafts for the treatment of urethral stricture began a new stage in the search for a definitive treatment for this type of patient.The aim of our article was to present a surgical technique for the treatment of UroLume®-associated bulbar urethral stricture that has not been described in the literature.A 71-year-old man presented with bulbar urethral stricture secondary to transurethral resection of the prostate who, 8 years ago, had UroLume® placement. He presented with another urethral stricture and was treated with numerous urethral dilations. Through the perineal approach, the endoprosthesis was completely removed, and based on the local tissue characteristics, a dorsal inlay and ventral onlay double buccal mucosa graft was placed with successful results at the 6th month of follow-up

The Feynman effective classical potential in the Schr\"odinger formulation

New physical insight into the correspondence between path integral concepts and the Schr\"odinger formulation is gained by the analysis of the effective classical potential, that is defined within the Feynman path integral formulation of statistical mechanics. This potential is related to the quasi-static response of the equilibrium system to an external force. These findings allow for a comprehensive formulation of dynamical approximations based on this potential.Comment: 10 pages, 4 figure

Spectropolarimetric multi line analysis of stellar magnetic fields

In this paper we study the feasibility of inferring the magnetic field from polarized multi-line spectra using two methods: The pseudo line approach and The PCA-ZDI approach. We use multi-line techniques, meaning that all the lines of a stellar spectrum contribute to obtain a polarization signature. The use of multiple lines dramatically increases the signal to noise ratio of these polarizations signatures. Using one technique, the pseudo-line approach, we construct the pseudo-line as the mean profile of all the individual lines. The other technique, the PCA-ZDI approach proposed recently by Semel et al. (2006) for the detection of polarized signals, combines Principle Components Analysis (PCA) and the Zeeman Do ppler Imaging technique (ZDI). This new method has a main advantage: the polarized signature is extracted using cross correlations between the stellar spectra nd functions containing the polarization properties of each line. These functions are the principal components of a database of synthetic spectra. The synthesis of the spectra of the database are obtained using the radiative transfer equations in LTE. The profiles built with the PCA-ZDI technique are denominated Multi-Zeeman-Signatures. The construction of the pseudo line as well as the Multi-Zeeman-Signatures is a powerful tool in the study of stellar and solar magnetic fields. The information of the physical parameters that governs the line formation is contained in the final polarized profiles. In particular, using inversion codes, we have shown that the magnetic field vector can be properly inferred with both approaches despite the magnetic field regime.Comment: Accepted for publication in Astronomy and Astrophysic

Nanoparticles doped with methyl jasmonate: foliar application to Monastrell vines under two watering regimes. An alternative to improve grape volatile composition?

Financial support was given by the Ministerio de Ciencia, Innovación y Universidades for projects RTI2018‐096549‐B‐I00 and RTI‐2018‐095794‐A‐C22. EP Pérez‐Álvarez thanks the Ministerio de Ciencia, Innovación y Universidades for her Juan de la Cierva‐Incorporación postdoctoral contract (IJC2019‐040502‐I). GBRR also acknowledges the Junta de Andalucía for her postdoctoral contract within the PAIDI 2020 program (DOC_01383).Background: Elicitors induce defense mechanisms, triggering the synthesis of secondary metabolites. Irrigation has implications for a more sustainable viticulture and for grape composition. The aim was to investigate the influence on grape aroma composition during 2019 and 2020 of the foliar application of amorphous calcium phosphate (ACP) nanoparticles and ACP doped with methyl jasmonate (ACP-MeJ), as an elicitor, with rainfed or regulated deficit irrigation (RDI) grapevines. Results: In both growing seasons, nearly all terpenoids, C13 norisoprenoids, benzenoid compounds and alcohols increased with ACP-MeJ under the RDI regimen. In 2019, under the rainfed regime, ACP treatment increased limonene, p-cymene, α-terpineol, 1,1,6-trimethyl-1,2-dihydronaphthalene (TDN), 2-ethyl-1-hexanol, (E,E)-2,4-heptadienal, and MeJ concentration in comparison with control grapes. In 2020, the rainfed regime treated with ACP-MeJ only increased the nonanoic acid content. Grape volatile compounds were most influenced by season and watering status whereas the foliar application mainly affected the terpenoids. Conclusion: A RDI regime combined with the elicitor ACP-MeJ application could improve the synthesis of certain important volatile compounds, such as p-cymene, linalool, α-terpineol, geranyl acetone, β-ionone, 2-phenylethanol, benzyl alcohol, and nonanoic acid in Monastrell grapes. © 2023 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.Ministerio de Ciencia, Innovación y Universidades RTI2018‐096549‐B‐I00, RTI‐2018‐095794‐A‐C22, IJC2019‐040502‐I MCIUJunta de Andalucía DOC_0138

Application of Elicitors, as Conventional and Nano Forms, in Viticulture: Effects on Phenolic, Aromatic and Nitrogen Composition of Tempranillo Wines

The phenolic, aromatic and nitrogen composition of a wine determines its organoleptic profile and quality. Elicitors have been used as a tool to stimulate the plant’s defense systems, favoring the synthesis of secondary metabolites. In this pioneering study, the elicitor methyl jasmonate in conventional form (MeJ) and in nanoparticle form (ACP-MeJ), with a concentration ten times lower, was applied in a Tempranillo vineyard over two seasons. The phenolic, nitrogen and volatile composition and the sensory properties of the MeJ-based wines were determined. The results showed that the effects of foliar applications of MeJ modify the wine composition. Thus, although the total concentration of most of the groups of phenolic compounds was not altered, several compounds, such as petunidin-3-glucoside, quercetin-3-glucoside, epigallocatechin and most of the stilbenes, increased, in both years, in the treated wines. Amino acids were influenced differently in each of the years studied, and volatile compounds generally did not improve in the treated wines. However, the ACP-MeJ wines were the best rated by the tasters, highlighting their equilibrium on the taste and their genuineness and odor quality. Therefore, foliar applications of ACP-MeJ can be considered a useful tool to improve wine quality.Spanish Government RTI2018-096549-B-I00 RTI-2018-095794-A-C2