Regularity theory and high order numerical methods for the (1D)-fractional Laplacian

This paper presents regularity results and associated high-order numerical methods for one-dimensional Fractional-Laplacian boundary-value problems. On the basis of a factorization of solutions as a product of a certain edge-singular weight $w$ times a ``regular´´ unknown, a characterization of the regularity of solutions is obtained in terms of the smoothness of the corresponding right-hand sides. In particular, for right-hand sides which are analytic in a Bernstein Ellipse, analyticity in the same Bernstein Ellipse is obtained for the ``regular´´ unknown. Moreover, a sharp Sobolev regularity result is presented which completely characterizes the co-domain of the Fractional-Laplacian operator in terms of certain weighted Sobolev spaces introduced in (Babu{s}ka and Guo, SIAM J. Numer. Anal. 2002). The present theoretical treatment relies on a full eigendecomposition for a certain weighted integral operator in terms of the Gegenbauer polynomial basis. The proposed Gegenbauer-based Nystr"om numerical method for the Fractional-Laplacian Dirichlet problem, further, is significantly more accurate and efficient than other algorithms considered previously. The sharp error estimates presented in this paper indicate that the proposed algorithm is spectrally accurate, with convergence rates that only depend on the smoothness of the right-hand side. In particular, convergence is exponentially fast (resp. faster than any power of the mesh-size) for analytic (resp. infinitely smooth) right-hand sides. The properties of the algorithm are illustrated with a variety of numerical results.Fil: Acosta, Gabriel. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Matemática; ArgentinaFil: Borthagaray, Juan Pablo. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Matemática; ArgentinaFil: Bruno, Oscar Ricardo. California Institute Of Technology; Estados UnidosFil: Maas, Martín Daniel. Consejo Nacional de Investigaciónes Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; Argentin

Stereoselective Metal-Catalyzed Transformations for Carbon-Boron Bond Formation and Carbon-Nitrogen Bond Cleavage

Tesis doctoral inédita leída en la Universidad Autónoma de Madrid, Facultad de Ciencias, Departamento de Química Orgánica. Fecha de lectura: 02-12-2019In the first chapter we have developed an enantioselective copper-catalyzed desymmetrization of meso-cyclobutenes for the synthesis of enantiomerically enriched cyclobutylboronates. This was the first catalytic enantioselective synthesis of this family of compounds. Through this methodology we have prepared a broad scope of cyclobutanes with high levels of diastereo- and enantioselectivity with up to four stereogenic centers.We have also developed some strategies to synthetize useful synthetic intermediates from the cyclobutylboronates. In the second chapter of this Doctoral Thesis we have developed a stereospecific copper-catalyzed substitution reaction of propargylic ammonium salts with aryl Grignard reagents. The reaction was completely -regioselective and stereospecific. Also, the functional group tolerance of the reaction is excepcional. In addition, no added ligand was needed, and we simply used an inexpensive copper salt. In the second part of this chapter, we developed a strategy for the synthesis of enantiomerically enriched allenes using alkyl Grignard reagents instead of aryl Grignard reagents. With this strategy we bypassed the problem of the allene racemization when alkyl magnesium halides are used. In the last chapter of this thesis, we have developed a new methodology for the allyl-allyl cross-coupling reaction between allylic carbonates or ammonium salts and allyl boronates. The reaction was completely regioselective and stereospecific and we have observed complete inversion in the configuration of the chiral center. We have also developed strategies for the selective functionalization of the different double bondsEn el segundo capítulo, se ha desarrollado el primer método enantioselectivo catalizado por cobre para la desimetrización de ciclobutenos, logrando la síntesis de ciclobutilboronatos quirales. Esta metodología fue la primera catalítica enantioselectiva de esta clase de compuestos. Los ciclobutilboronatos obtenidos presentaron altos niveles de diastereo- y enantioselectividad con hasta 4 centros estereogénicos en la molécula. También desarrollamos métodos para sintetizar valiosos intermedios sintéticos a partir de los productos obtenidos. En el tercer capítulo de la presente Tesis Doctoral hemos desarrollado una metodología para la sustitución nucleófila estereoespecífica con reactivos de Grignard arílicos de sales de amonio propargílicas catalizada por cobre. La reacción fue completamente regioselectiva y enantioespecífica. Además, la reacción presento una alta compatibilidad con diversos grupos funcionales sin la necesidad de añadir un ligando. En la segunda parte de este capítulo, utilizamos esta estrategia para la síntesis de alenos enantioméricamente enriquecidos usando reactivos de Grignard alquílicos en lugar de arílicos. Mediante esta estrategia conseguimos evitar la racemización que presentan este tipo de reacciones. En el último capítulo de esta Tesis Doctoral, hemos desarrollado una nueva metodología para el acoplamiento alilo-alilo entre carbonatos o sales de amonio alílicas y boronatos alílicos. La reacción fue completamente regioselectiva y enantioespecífica y observamos una inversión completa del centro quiral. También, hemos desarrollado estrategias para la funcionalización selectiva de los diferentes dobles enlaces que se forman en la reacción

Site index estimation using airborne laser data in Eucalyptus dunnii Maide stands in Uruguay

Premio extraordinario de Trabajo Fin de Máster curso 2020/2021. Máster en Geomática, Teledetección y Modelos Espaciales Aplicados a la Gestión ForestalThe estimation of forest variables to support a forest inventory can be approached through the use of different technologies. Although field sampling is the most widely implemented technique, the development of remote sensing techniques increases the possibilities of action in this field. One of these technologies is the airborne LiDAR scanner (ALS). In this study, linear models and non-parametric models with Random Forest imputation were generated to estimate the total height (HT) and site index (SI) of Eucalyptus dunnii Maide, based on LiDAR metrics. High spatial resolution continuous rasters for HT and SI were created with these models. The use of a semi-automatic object-oriented segmentation algorithm for stand delimitation based on the SI raster was then carried out. To evaluate the performance of these models, the One Leave One cross-validation technique was implemented, determining for each model the ratio between the RMSE of the model and the RMSE of the cross-validation (RMSEcv). Linear models for HT estimation presented a better fit (R2=0.84, RMSE=0.84 m, MAPE=0.039, Bias=0.002) than the Random Forest (R2=0.85, RMSE=1.26 m, MAPE=7.19, Bias=-0.173) model including only independent variable the 99th percentile. The RMSE/RMSEcv ratio presented a higher value for the linear model (0.93) than Random Forest (0.75). For the estimation of the site index (SI), the Random Forest model was applied, which included the LiDAR metrics corresponding to the 99th percentile and the 80th bicentile. This model had an R2 value of 0.65 and an RMSE value of 1.62 m. Then, on the SI raster generated by the Random Forest model, automatic segmentation was applied, generating segments with high internal homogeneity and low homogeneity between segments. The methodology developed in this work provides accurate estimates and mapping of HT and SI at stand scale based on LiDAR data. In addition, an automatic segmentation method was applied, generating stands based on the SI. This segmentation is very useful for the sector as it is a tool that will improve forest management in terms of harvesting and future plantations

Reactivo de Lugol: Historia de su descubrimiento y aplicaciones didácticas

Our paper is a brief historical study of aqueous solutions of potassium iodide and iodine. It also analyzes why, in Biology and Medicine, these solutions are known as Lugol reactive. Moreover, we study their use for educational purposes to deepen in various topics such as redox reactions and the relationship between solubility and bond types

The Sources of Quality in the Pharmaceutical Industry

This paper analyzes the sources of quality of a pharmaceutical product. After identifying eight quality dimensions, a framework of hypothetical sources that contribute the most to shape those dimensions is established. The framework, based on Garvin’s pioneering work, is applied to case studies of laboratories operating in Argentina. Framework relevance is considered using correlation analysis. Laboratories are ranked through expert opinion by the quality of its products using the eight dimensions mentioned above; it is observed that there is no perfect parallelism in ranking along all dimensions, possibly revealing different managerial priorities and uses of resources among laboratories, as well as different sources of quality and different business strategies. Correlation analysis also suggests that the study of a pharmaceutical product is a complex task when a modern concept of quality is considered. Once the existence of different quality dimensions is accepted, the following two questions are investigated: (1) Are there specific sources of quality that support some dimensions (and not others) and that are based on identifiable organizational aspects or specific technologies? (2) What are the generic sources of quality (affecting all dimensions) and in what way do they contribute to improve performance or highlight quality dimensions? It is assumed as a starting point that among the sources of quality there are generic sources, affecting all dimensions, and specific sources, which affect only some dimensions. In concrete cases, specific quality sources are identified, although the search for specific quality sources for each dimension is not conclusive. The study of generic quality sources, however, suggests that corporate systems, corporate culture, and management policies contribute to incorporate quality in a product. Thus quality results from the interaction between generic and specific sources. In the final part of the paper, recommendations for academics and industrialists are provided, as well as some conclusions.Pharmaceutical product, Garvin’s quality dimensions, quality sources, pharmaceutical laboratories in Argentina, corporate systems, corporate culture.

Inflation targeting, disinflation, and debt traps in Argentina

This paper highlights the role of external indebtedness and the presence of inflationary inertia in order to assess the effectiveness and sustainability of inflation targeting during disinflation episodes. As the recent Argentinian experience illustrates, a sluggish inflation rate and a significant currentaccount deficit may make the stabilization process difficult. To illustrate the point, we build a model that shows that, when inflation adjusts fast, the target may be achieved without building too much external debt. But if inflation adjusts slowly, an excessive build-up of external debt could lead to an increase in the risk premium, a sudden shortage of foreign exchange, and the eventual collapse of the inflation-targeting regime.Fil: Libman, Emiliano. Centro de Estudios de Estado y Sociedad; Argentina. Universidad Nacional de San Martín; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Palazzo, Gabriel Martín. Centro de Estudios de Estado y Sociedad; Argentina. Universidad de Buenos Aires; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

On the Analysis of the Contact Conditions in Temporomandibular Joint Prostheses

Temporomandibular joint replacement (TMJR) is a complex surgical procedure in which the artificial joints available must assure the anatomical reconstruction and guarantee a good range of the natural temporomandibular joint (TMJ) movements. With this aim, different types of TMJ prostheses, including the stock prosthetic system and custom-made prostheses, are being currently implanted. Although temporomandibular joint replacements (TMJRs) are expected to accomplish their function during a number of years, they might actually fail and need to be replaced. This paper analyzes different design factors affecting the contact stress distributions within the TMJ prosthesis interface, which are consequently involved in their deterioration and final failure of the prosthetic device. With this purpose, a numerical model based on finite elements has been carried out in order to evaluate the stress states attained in different prosthesis configurations corresponding to general types of TMJ prostheses. On the other hand, the actual degradation of resected implants has been evaluated via optical microscopy. The linkage between the numerical simulations performed and experimental evidence allowed the authors to establish the different wear and damage mechanisms involved in the failure of stock TMJ prostheses. Indeed, the results obtained show that the contact stresses at the interface between the mandible and the glenoid fossa components play a key role in the failure process of the TMJR devices