Strong light-matter coupling: from traditional to cavity-free polaritons

Polaritons are formed when light and matter interact strongly. For this to occur, photons and transitions in a material must exchange energy faster than the dissipation rate of the interacting components. Polaritons have shown the ability to change such material properties as photophysics, chemical reaction rates, transport, etc. Most of the studies on strong coupling use an external cavity. These sort of platforms form what here are called traditional polaritons. Moreover, such a cavity is often made of two metallic mirrors, which restrict access to the material. The first part of the thesis is devoted to traditional polaritons in a microcavity-plasmon coupling platform. The versatility of the platform allows to achieve strong and ultrastrong coupling at room temperature. The second part is dedicated to cavity-free or self-hybridized polaritons. Here it is shown that polaritons can be sustained by the material with the transition resonance itself, by reshaping it into simple structures as slabs, cylinders, and spheres. The structures reveal a minimal critical size for polaritons to exist. Moreover, the coupling strength seems to be limited only by the macroscopic optical properties of the material. These results can guide the community to quickly realize which materials can be used to form polaritons and to find them in simpler structures. Since the structures are not restricted by an external cavity, a window of opportunity is open for applications and further studies on the impact of polaritons on material properties

Semi-automatic Evaluation of Fetal Growth Restriction using Ultrasound Images

Fetal growth restriction (FGR) is a condition where the developing fetus is unable to achieve the expected growth potential for its gestational age. It is the second leading cause of perinatal mortality and fetuses are more susceptible to the onset of numerous long-term diseases. Thus, early diagnosis and effective monitoring of FGR are very important. Ultrasound is the most widely used medical imaging technique for the diagnosis and surveillance of growth-restricted fetuses. In current clinical practice, to obtain an estimate of fetal age it is necessary to perform the measurement of four biometric indices. Apart from manually tracing being time-consuming and highly dependent on clinicians, the intra- and inter-observer variability influences the accuracy and consistency of measurements. Since clinicians believe that the liver of fetuses in the lowest percentiles is one of the most determinant indicators to detect changes in fetal development, this dissertation aimed to pro- pose a novel approach that attempts to correlate the fetal liver echogenicity and the diagnosis of FGR, using image processing techniques and Machine Learning models. One of the advan- tages of this method is that it can improve the effectiveness of FGR diagnosis by eliminating the need for an exhaustive collection of biometric indices. To this purpose, a computer-assisted tool was developed which allows manual segmen- tation of a portion of the fetal liver. Next, a textural analysis of the various segments was performed. Finally, in order to identify the best classification model that distinguishes fetuses with FGR from those with normal fetal growth based on their textural features, five supervised learning models were trained and evaluated. After a comparative analysis, the results showed that the model that produced the best results was the Decision Tree, with an accuracy of 0.77 and an area under the receiver operating characteristic (AUROC) curve of 0.62. Although the results obtained cannot be considered highly conclusive due to the limited and unrepresentative nature of the available dataset, it is possible to state that the proposed approach is feasible and has the potential to establish a correlation between the echogenicity of the fetal liver and changes in fetal development. However, to arrive at definitive conclusions, it will be necessary to delve deeper into the study that has been initiated, using a larger volume of data.A restrição do crescimento fetal (RCF) ocorre quando o feto não atinge o potencial de cres- cimento determinado para a sua idade gestacional. É a segunda principal causa de morte perinatal e os fetos são mais suscetíveis a contrair inúmeras doenças a longo prazo. Desta forma, o diagnóstico precoce e a monitorização eficaz da RCF são muito importantes. A ecografia é a técnica de imagem médica mais utilizada para o diagnóstico e a vigilância de fetos com um crescimento restrito. Na prática clínica atual, para obter uma estimativa da idade do feto é necessário realizar a medição de quatro índices biométricos. Para além do rastreio manual ser demorado e muito dependente dos clínicos, a variabilidade intra- e inter-observadores influencia a precisão e consistência das medições. Dado que os clínicos acreditam que o fígado dos fetos nos percentis mais baixos é um dos indicadores mais determinantes para detetar alterações no desenvolvimento fetal, esta disser- tação teve como principal objetivo propor uma abordagem inovadora que tenta correlacionar a ecogenicidade do fígado fetal e o diagnóstico da RCF, utilizando técnicas de processamento de imagem e modelos de Aprendizagem Automática. Uma das vantagens deste método é que pode melhorar a eficácia do diagnóstico da RCF ao eliminar a necessidade de uma recolha exaustiva dos índices biométricos. Nesse sentido, foi desenvolvida uma ferramenta que permite realizar a segmentação ma- nual de uma porção do fígado fetal. Em seguida, foi realizada uma análise textural dos vários segmentos. Por último, de modo a identificar o modelo de classificação que melhor distingue os fetos com RCF dos fetos com um crescimento fetal normal com base nas suas caracterís- ticas texturais, foram treinados e avaliados cinco modelos de aprendizagem supervisionada. Após uma análise comparativa, foi possível concluir que o modelo que produziu os melhores resultados foi a Árvore de Decisão, com uma precisão de 0.77 e uma área sob a curva Receiver Operating Characteristic (ROC) de 0.62. Embora os resultados obtidos não se possam considerar muito conclusivos, uma vez que o conjunto de dados disponível era bastante limitado e pouco representativo, é possível afirmar que a abordagem proposta é viável e que apresenta potencial para estabelecer uma relação entre a ecogenicidade do fígado fetal e as alterações no desenvolvimento do feto. No entanto, para obter conclusões definitivas, será necessário aprofundar o estudo agora iniciado, recor- rendo a um maior volume de dados

The Political Incorporation of Latino Immigrants in California

This paper explores and analyzes the political incorporation of Latino immigrants in California over the last several decades. Political incorporation refers to the process through which immigrants and their descendants claim their political rights and exercise their voice in politics. In order to understand the impact of Latino immigration on California state politics, the paper first examines the demographic changes in the state. This paper then provides an overview of all of the major immigration legislation in California, beginning from the anti-immigration initiatives to the California Dream Act and immigration-friendly legislation that Governor Jerry Brown signed into law in 2013

Laccase-based technologies to remove organic pollutants from soils and wastewaters

Pollution of soil and water is an environmental issue worldwide. Thereby, the development and implementation of low-cost and eco-friendly treatments for the decontamination of polluted sites and wastewater is a priority. In this regard, the use of biological agents, as white rot fungi, to degrade and detoxify environmental contaminants has emerged as a potential alternative. These microorganisms have been reported to remove a wide range of xenobiotics by the action of the extracellular lignin-modifying enzymes, such as peroxidases and laccases. Laccases (copper-containing oxidases, EC 1.10.3.2) are promising biocatalysts due to their oxidative versatility and low catalytic requirements. Laccases, as well as laccase-mediator systems, have been successfully used to oxidatively detoxify and remove a great number of contaminants. The potential of laccase is explored in the current research aiming to develop continuous or semicontinuous technologies to remove pollutants of concern, such as Polycyclic Aromatic Hydrocarbons (PAHs) and Emerging Organic Contaminants (EOCs), from real environmental matrices. In the first section of the Thesis, the use of laccase is investigated to degrade PAHs. The natural biodegradation of these toxic pollutants is restricted by two major factors: low water solubility and high hydrophobicity, which make PAHs persistent pollutants in soil. Extraction with solvents or surfactants is an alternative to remove PAHs from soils. However, this technique by itself does not degrade the pollutants, but only attains their transfer to another phase. Enzymatic remediation with laccase may be a feasible alternative, but requires the addition of surfactants or solvents to increase the pollutant bioavailability for the enzymatic action. Initially, different reactor configurations (micellar, biphasic and the combination of both) were evaluated to perform the laccase-catalyzed degradation of anthracene, the model PAH. The use of a Two Phase Partitioning Bioreactor (TPPB) with silicone oil and the addition of surfactant in the aqueous phase allowed the enzymatic treatment of high loads of anthracene at fast conversion rate. Subsequently, the use of vegetable oils (sunflower or pomace olive oil) as organic phase in the TPPB was proposed to dissolve high concentrations of the target pollutant. Pomace olive oil led to the best results and after optimizing the operational conditions in the TPPB, a novel remediation process to remove anthracene from polluted soils was proposed. The process consisted of the extraction of anthracene from the soil by the oil followed by its degradation in a surfactant-assisted TPPB, operated with a laccase-mediator system. The main outcomes of this study showed high extraction efficiency for pomace olive oil and high removal rate of anthracene in the TPPB. Moreover, the feasibility of reusing both the aqueous and organic phases of the TPPB in successive batches of anthracene degradation in the reactor was also demonstrated. The second section of the Thesis focuses on the enzymatic removal of EOCs from aqueous systems. The industrial chemical bisphenol A and pharmaceuticals active compounds are examples of EOCs frequently detected in wastewaters, considered as the main source of EOCs entering the environment. The application of laccases in tertiary wastewater treatment requires the retention of the biocatalyst in the reactor. In the current research, two main approaches were considered to fulfill such requirement. On one hand, the use of an enzymatic membrane reactor with a ceramic membrane was considered to perform the continuous removal of BPA from secondary effluent by free laccase. The second approach consisted of the immobilization of laccase onto nanoparticles or magnetic microparticles, prior to its application to remove micropollutants from secondary effluents. Immobilization not only facilitated the retention of the biocatalyst in the system by a high pore size membrane or by applying an external magnetic field, but also increased laccase stability

La probabilidad y la estadística en la construcción del pensamiento matemático del niño preescolar

Esta investigación, en curso y cualitativa, trata la introducción de nociones de probabilidad y de estadística en la educación preescolar mexicana, la comprensión de los niños de esas nociones resultante de su enseñanza y a qué otras de sus nociones matemáticas favorece el proceso. Sus referentes teóricos consideran las ideas fundamentales de estocásticos para el curriculum y el origen de la idea de azar en el niño; el cognitivo, el rol de la intuición en la adquisición de nociones de estocásticos; el social, el rol de la interacción en el aula en esa adquisición. Su primera fase examina la propuesta institucional para preescolar; la segunda, la docencia y su formación y, la tercera, la enseñanza de estocásticos en un aula con 25 niños de 3 a 4 años de edad y otra con 30 niños de 5 años. Los resultados indican que para la educación preescolar no se considera el valor formativo de su estudio, no obstante que los niños son sensibles a las ideas de azar y de probabilidad y que la docencia requiere formación en estocásticos

La formación docente de preescolar en estocásticos

Esta investigación se orienta, epistemológicamente, por las ideas fundamentales de estocásticos para el currículum (Heitele, 1975) y el origen de la idea de azar en el niño (Piaget e Inhelder, 1951); cognitivamente, por el rol de la intuición en las ideas de estocásticos (Fischbein, 1975); y socialmente por el papel de la interacción en el aula en la adquisición de nociones de probabilidad y de estadística (Steinbring, 1991). De forma cualitativa se caracterizó la comprensión de ideas de estocásticos de dos docentes en ejercicio y 25 en formación y su enseñanza en el aula real de preescolar, durante la impartición de un estudio dirigido a estocásticos para su enseñanza. De la experienciación desarrollada, de las bitácoras y de la aplicación de cuestionarios, resultó la necesidad de formar a la docencia en probabilidad y en estadística para desarraigar la prevalencia del determinismo en su enseñanza y posibilitar así la introducción de nociones de estocásticos como vía hacia la construcción del pensamiento matemático del niño preescolar

Cooperative approach to a location problem with agglomeration economies

This paper considers agglomeration economies. A new firm is planning to open a plant in a country divided into several regions. Each firm receives a positive externality if the new plant is located in its region. In a decentralized mechanism, the plant would be opened in the region where the new firm maximizes its individual benefit. Due to the externalities, it could be the case that the aggregated utility of all firms is maximized in a different region. Thus, the firms in the optimal region could transfer something to the new firm in order to incentivize it to open the plant in that region. We propose two rules that provide two different schemes for transfers between firms already located in the country and the newcomer. The first is based on cooperative game theory. This rule coincides with the nucleolus and the t-value of the associated cooperative game. The second is defined directly. We provide axiomatic characterizations for both rules. We characterize the core of the cooperative game. We prove that both rules belong to the core

Decisiones robustas en la producción agrícola para dos períodos : Primera aproximación a las estrategias adaptativas

La presentación se basará en el desarrollo y análisis de una Metodología de Decisiones Robustas con el propósito de ayudar a los productores agrícolas a decidir qué cultivos implantar para dos campañas de producción. El objetivo principal del trabajo es hacer una primera aproximación para agregar al planteo de Decisiones Robustas la posibilidad de evaluar y modificar las decisiones en escenarios que duren más de un período, logrando de esta manera elaborar planes a largo plazo. Asimismo, trabajar con estas Estrategias Adaptativas da la posibilidad de hacer correcciones en las decisiones de cultivo en base a los resultados obtenidos en períodos anteriores. Se presentará una primera aproximación del enfoque, con sus resultados preliminares.The presentation will review the development and analysis of a Robust Decisions Methodology in order to help farmers decide which crops introduce in two production campaigns. The main objective of this work is to make a first step to apply Adaptive Strategies into a Robust Decision Methodology. This will permit decision maker to assess and change decisions in scenarios that last more than one period in order to achieve long term planning goals. In addition, working with these adaptive strategies gives the opportunity to make corrections in planting decisions based on the results obtained in previous periods. We will present a first approach with its preliminary results.Sociedad Argentina de Informática e Investigación Operativa (SADIO