ADVANCED BIOMATERIALS FROM RENEWABLE RESOURCES: AN INVESTIGATION ON CELLULOSE NANOCRYSTAL COMPOSITES AND CO2 EXTRACTION OF RENDERED MATERIALS

The annual global consumption of petroleum-based plastics is approximately 280 million tons and is impacting the sustainability of our planet and prosperity of future generations. One solution is the development of bio-based polymer materials with advanced properties for commercial applications. Therefore, the ultimate goal of this dissertation is to investigate the properties of new bio-based materials for broader applications. This dissertation includes two research areas: cellulose nanocomposites, and CO2 extractions of rendered fat. In the first half, cellulose nanocrystals (CNCs), which exhibit excellent mechanical and optical properties, were investigated for the reinforcement of a biodegradable polymer. The properties of these nanocomposites were studied to intellectually contribute to the understanding of the reinforcement mechanisms of CNC nanocomposites. In the second half, a more efficient and greener extraction of fat from rendered materials (RMs) was explored to broaden their potential applications, which include protein-based polymers and biofuels. Since CNCs are hydrophilic, surface modification with various surfactants was first accomplished in this research, increasing the dispersion stability in non-polar solvents by at least a month. Only 1 wt.% of surfactant with respect to CNCs was needed to afford a significant increase in the CNC stability, representing a much lower percentage than the values reported in the literature. Moreover, these CNCs showed the ability to self-assemble into local liquid crystal structures, a potential advantage for polymer reinforcement. CNCs were subsequently investigated as an additive for polylactic acid (PLA), which is the most widely used synthetic biopolymer in the market. CNC addition yielded a 61% increase in toughness at 1 wt.% CNC load. The tensile strength and modulus were not affected by the CNC addition, addressing one of the most frequent issues in the toughening of polymers. In addition, polarized microscopy revealed self-assembly formation of the enhanced composites indicating that the reinforcement was influenced by the CNC nanoscale structure on the matrix. These structures were found to be distributed in different directions along the extrusion line, suggesting that an angled CNC orientation favored a higher toughness as observed in natural cellulose fibers. PLA was also modified by grafting polyacrylic acid (PAA), which provided a stiffer and more hydrophilic surface for the addition of unmodified CNCs. In this case, the toughness of the PLA copolymer decreased with CNC concentration, while the tensile modulus increased. This effect was attributed to an increase of polymer crystallinity upon addition of CNCs, probably due to an enhanced compatibility provided by the PAA chains. For the purpose of obtaining a more efficient separation of proteins and fats from RMs, liquid and supercritical CO2 (LCO2 and SCCO2) were explored as solvents for the extraction, demonstrating the ability to extract up to 97% of the fat in the RMs. Higher fat solubilities in LCO2 were obtained compared to SCCO2, a result attributed to a retrograde phenomenon. These results are advantageous for the separation of rendered fats at relatively low temperatures and pressures, obtaining higher yields than screw pressing currently used in the industry. However, this extraction requires high amounts of CO2 due to low fat solubilities. This issue was addressed using CO2-assisted mechanical extraction, resulting in yields up to 81%, representing a 98% increase compared to conventional extraction, and significantly reducing the amount of CO2 for the extraction

El secreto bancario: los alcances de su flexibilizacin como requisito del ingreso de Chile a la Organizacion Economica de Cooperacion y Desarrollo (OCDE)

73 p. La siguiente tesis no es autorizada por el autor para su difusión en formato digitalEl siguiente trabajo trata principalmente del análisis a la figura del secreto bancario, su posible flexibilización como consecuencia de los requerimientos exigidos por la OCDE, para que Chile pueda formar parte de ésta. Esta investigación se desarrolla utilizando una metodología jurídico dogmática, además de realizar un análisis del proyecto de ley que modifica el actual artículo 62 del Código Tributario, estableciendo normas que permitan el acceso a la información bancaria por parte de la autoridad tributaria, facultando al Director nacional del Servicio de Impuestos Internos para que pueda requerir información relativa a operaciones bancarias para dar cumplimiento a un convenio internacional, compromisos de intercambio de información, como para satisfacción de su función fiscalizadora, determinando si el proyecto vulnera las garantías de un debido proceso y finalmente analizamos las implicancias del posible ingreso de Chile a la OCDE./ ABSTRACT: Following work analyzes, mainly, the banking secrecy legal figure, and its possible flexibilization as a consequence of OCDE’s demanded requirements in order to Chile become part of it. This research is developed using a legal dogmatic methodology through which banking secrecy understanding is expected, plus an actual Tribute Code 62th article modification law project analysis, establishing a frame within which the tribute authority can access the banking information, allowing the National Internal Revenue Service director so he can gather information related to banking operations in order to fulfill an international agreement, information exchange, to satisfy its controlling function, determining if the project breaks a due process guarantees and finally a possible membership of Chile into OCDE implications analysis

Tratamento precoce em doentes com maloclusao de clase III: Relatório de uma série de casos

Introduction: There in the study of Class III malocclusion various terms, one of the most currently used is that described by Moyers, who described the class III molar relationship and anterior crossbite and also classified as Class III skeletal or true muscle or false teeth. Materials and Methods: Patient selection for this study involves the evaluation of all patients seen in practice dentist consultation of Social Services at the Clinic of Pediatric Dentistry Level Undergraduate Faculty of Pediatric Dentistry of the Universidad Autonoma de San Luis Potosi patients had exhibited some features of development prognathism. He proceeded to place the resin in anterior teeth, and verification prior diganostico met the inclusion criteria. Results: The patients modified their closure, reorientation of jaw closure, the first step of getting bitten up edge to edge occlusion redirected. Discussion: Basically, interceptive treatment of malocclusion Pseudo Class III, the challenge is directed to the reorientation of jaw closure, removal of occlusal contacts and the correction of maxillo-mandibular. Conclusion: The changes facial, dental and skeletal cephalometric measurements were based on, and clinical observations of patients seeking treatment are more conservative, less processing time in an office visit and no risk of open bite problem.Introducción: Existen dentro del estudio de la maloclusión clase III diversos términos, uno de los mas empleados en la actualidad es el descrito por Moyers, quien describió la relación molar de clase III y mordida cruzada anterior y además clasifica la clase III como esqueletal o verdadera, muscular o falsa y dentaria. Materiales y Métodos: La selección de pacientes para el presente estudio envuelve la evaluación de todos los pacientes vistos en la practica odontopediatrica de la consulta de Servicio Social en la Clínica de Odontopediatria a Nivel Pregrado de la Facultad de Odontopediatria de la Universidad Autónoma de San Luis Potosí; Los pacientes que se presentaron exhibieron algunas características de desarrollo prognatico mandibular. Se procedió a colocar resina en los dientes anterosuperiores, previo diganostico y verificación que cumplía con los criterios de inclusión. Resultados: Los pacientes modificaron su oclusión, reorientación del cierre mandibular, de un primer paso de quedar mordida borde a borde hasta una oclusión reorientada. Discusión: Básicamente, para el tratamiento interceptivo de la maloclusión Pseudo clase III, el reto se dirige a la reorientación del cierre mandibular, la eliminación de contactos oclusales prematuros y la corrección de la maxilo-mandibular. Conclusión: Los cambios faciales, dentales y esqueléticos fueron basados en medidas cefalometricas, y observaciones clínicas de los pacientes, se busco el tratamiento más conservador, menor tiempo de elaboración, en una visita al consultorio y sin riesgo alguno de problema de mordida abierta.Introdução: Existem vários termos no estudo da má oclusão de classe III, um dos mais utilizados atualmente é o descrito por Moyers. Ele descreveu a relação molar de classe III e mordida cruzada anterior e ainda classifica a classe III como esquelética ou verdadeira, muscular ou falsa e dental.Materiais e métodos: A seleção dos pacientes para o presente estudo envolve a avaliação de todos os pa-cientes atendidos na prática de odontopediatria da consulta de Serviço Social da Clínica de Odontopediatria do Nível de Graduação da Faculdade de Odontopediatria da Universidade Autônoma de São Luís. Potosí. Os pacientes que se apresentaram apresentaram algumas características do desenvolvimento prognático man-dibular. A resina foi colocada nos dentes anteriores superiores, após diagnóstico e verificação de que atendia aos critérios de inclusão. Resultados: Os pacientes modificaram sua oclusão, reorientação do fechamento mandibular, de um primeiro passo de ser mordido borda a borda para uma oclusão reorientada. Discussão: para o tratamento interceptivo da má oclusão Pseudo classe III, o desafio está direcionado para a reorientação do fechamento mandibular, a eliminação dos contatos oclusais prematuros e a correção do maxilo-mandibular. Conclusão: As alterações faciais, dentárias e esqueléticas foram baseadas em medidas cefalométricas, e observações clínicas dos pacientes, procurou-se o tratamento mais conservador, o menor tempo de proces-samento, em uma visita ao consultório e sem nenhum risco de problemas de mordida aberta

An Economic Analysis on The Social Cost of Illegal Immigration

The purpose of this paper is to analyze the economic cost of illegal immigration in the United States since the 1990s and its consequences on American society. Indeed, illegal immigration has been a major topic of discussion among the main social issues during election cycles in the United States. Those who lean more conservative have argued that illegal immigration is an externality that increase social cost. They argue that illegal immigrants increase the cost of healthcare, public education, and welfare programs such as Medicaid and food stamps. And the cost falls on the American taxpayer. Those who lean more liberal argue that the government should create social programs to assist illegal immigrants in helping them adjusting and conforming their immigration status to the laws and customs of the United States. This paper has two objectives: (1) to determine if illegal immigration imposes a higher social cost on the American taxpayer based on a multivariate regression analysis, (2) to propose recommendations to help the illegal immigrants becoming legal while minimizing the future social cost of illegal immigration on the American taxpayer. Our findings show that there is a correlational relationship between illegal immigration and the cost of social welfare, and this correlational relationship is of strong magnitude

Un ejemplo practico de valoracion de acciones a traves de opciones : el caso CTC

115 p.El gran crecimiento económico que ha desarrollado nuestro país en los últimos años y las tendencias a la globalización del mercado han impulsado el perfeccionamiento del mercado de capitales chileno junto con la utilización de nuevos instrumentos financieros, como por ejemplo, las opciones; las cuales se pueden negociar en Chile desde 1981. Existen diferentes métodos para la valorización de las empresas y uno de los menos utilizados es a través de opciones. El patrimonio de la empresa es equivalente a una opción de compra, es decir, los accionistas adquieren el derecho a comprar los activos de la empresa a un precio de ejercicio equivalente al valor de la deuda. Con esta memoria se pretende entregar un caso practico de valoración de acciones de la Compañía de Telecomunicaciones de Chile, vía opciones, con el fin de entregar una base para nuevos estudios y, además, que permita la comparación y validación de sus resultados con modelos mas estudiados, como es el caso del modelo de Valoración de Activos de Capital (CAPM). Para lograr esto, la memoria se dividió en tres partes. La primera muestra el marco teórico que sustenta la investigación. La segunda desarrolla la metodología de trabajo y, al mismo tiempo, entrega los resultados obtenidos al aplicar esta metodología. Y la tercera parte muestra las conclusiones finales de la memoria. Dentro de la metodología se calculo el costo de capital de la empresa con el fin de conocer la tasa promedio ponderada exigida por los accionistas y los acreedores. Esta tasa fue de un 3,70%, para el periodo comprendido entre Diciembre de 1989 y Diciembre de 1996

InSAR-Based Early Warning Monitoring Framework to Assess Aquifer Deterioration

Aquifer surveillance is key to understanding the dynamics of groundwater reservoirs. Attention should be focused on developing strategies to monitor and mitigate the adverse consequences of overexploitation. In this context, ground surface deformation monitoring allows us to estimate the spatial and temporal distribution of groundwater levels, determine the recharge times of the aquifers, and calibrate the hydrological models. This study proposes a methodology for implementing advanced multitemporal differential interferometry (InSAR) techniques for water withdrawal surveillance and early warning assessment. For this, large open-access images were used, a total of 145 SAR images from the Sentinel 1 C-band satellite provided by the Copernicus mission of the European Space Agency. InSAR processing was carried out with an algorithm based on parallel computing technology implemented in cloud infrastructure, optimizing complex workflows and processing times. The surveillance period records 6-years of satellite observation from September 2016 to December 2021 over the city of Chillan (Chile), an area exposed to urban development and intensive agriculture, where ~80 wells are located. The groundwater flow path spans from the Andes Mountain range to the Pacific Ocean, crossing the Itata river basin in the Chilean central valley. InSAR validation measurements were carried out by comparing the results with the values of continuous GNSS stations available in the area of interest. The performance analysis is based on spatial analysis, time series, meteorological stations data, and static level measurements, as well as hydrogeological structure. The results indicate seasonal variations in winter and summer, which corresponds to the recovery and drawdown periods with velocities > −10 mm/year, and an aquifer deterioration trend of up to 60 mm registered in the satellite SAR observation period. Our results show an efficient tool to monitor aquifer conditions, including irreversible consolidation and storage capacity loss, allowing timely decision making to avoid harmful exploitation

Desarrollo Social y Derecho

El Estado y El Derecho, fenómenos sociales indisolublemente ligados entre si, surgen, ascienden y han ascendido por los escalones del Desarrollo Histórico. Se necesitan mutuamente y por ella no puede uno estudiarse sin la concurrencia del otro: la propia vinculación objetiva, real, entre ellos exige que se estudien en una unidad inseparable

Plant-growth promotion by proteobacterial strains depends on the availability of phosphorus and iron in Arabidopsis thaliana plants

Phosphorus (as phosphate, Pi) and iron (Fe) are critical nutrients in plants that are often poorly available in the soil and can be microbially affected. This work aimed to evaluate how plant-rhizobacteria interaction changes due to different Pi or Fe nutritional scenarios and to study the underlying molecular mechanisms of the microbial modulation of these nutrients in plants. Thus, three proteobacteria (Paraburkholderia phytofirmans PsJN, Azospirillum brasilense Sp7, and Pseudomonas putida KT2440) were used to inoculate Arabidopsis seeds. Additionally, the seeds were exposed to a nutritional factor with the following levels for each nutrient: sufficient (control) or low concentrations of a highly soluble source or sufficient concentrations of a low solubility source. Then, the effects of the combinatorial factors were assessed in plant growth, nutrition, and genetic regulation. Interestingly, some bacterial effects in plants depended on the nutrient source (e.g., increased aerial zones induced by the strains), and others (e.g., decreased primary roots induced by Sp7 or KT2440) occurred regardless of the nutritional treatment. In the short-term, PsJN had detrimental effects on plant growth in the presence of the low-solubility Fe compound, but this was not observed in later stages of plant development. A thorough regulation of the phosphorus content was detected in plants independent of the nutritional treatment. Nevertheless, inoculation with KT2440 increased P content by 29% Pi-deficiency exposed plants. Conversely, the inoculation tended to decrease the Fe content in plants, suggesting a competition for this nutrient in the rhizosphere. The P-source also affected the effects of the PsJN strain in a double mutant of the phosphate starvation response (PSR). Furthermore, depending on the nutrient source, PsJN and Sp7 strains differentially regulated PSR and IAA- associated genes, indicating a role of these pathways in the observed differential phenotypical responses. In the case of iron, PsJN and SP7 regulated iron uptake-related genes regardless of the iron source, which may explain the lower Fe content in inoculated plants. Overall, the plant responses to these proteobacteria were not only influenced by the nutrient concentrations but also by their availabilities, the elapsed time of the interaction, and the specific identities of the beneficial bacteria. (Figure presented.)Fil: Orellana, Daniela. Universidad Adolfo Ibañez; Chile. Center Of Applied Ecology And Sustainability; Chile. Millennium Science Initiative Program; ChileFil: Machuca, Daniel. Universidad Adolfo Ibañez; Chile. Center Of Applied Ecology And Sustainability; ChileFil: Ibeas, Miguel Angel. Universidad Andrés Bello; Chile. Millennium Science Initiative Program; ChileFil: Estevez, Jose Manuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquímicas de Buenos Aires. Fundación Instituto Leloir. Instituto de Investigaciones Bioquímicas de Buenos Aires; Argentina. Millennium Science Initiative Program; Chile. Universidad Andrés Bello; ChileFil: Poupin Swinburn, María Josefina. Universidad Adolfo Ibañez; Chile. Center of Applied Ecology and Sustainability; Chile. Millennium Science Initiative Program; Chil