Essays on Microeconometrics

My dissertation has three chapters which develop and apply microeconometric tech- niques to empirically relevant problems. All the chapters examines the robustness issues (e.g., measurement error and model misspecification) in the econometric anal- ysis. The first chapter studies the identifying power of an instrumental variable in the nonparametric heterogeneous treatment effect framework when a binary treat- ment variable is mismeasured and endogenous. I characterize the sharp identified set for the local average treatment effect under the following two assumptions: (1) the exclusion restriction of an instrument and (2) deterministic monotonicity of the true treatment variable in the instrument. The identification strategy allows for general measurement error. Notably, (i) the measurement error is nonclassical, (ii) it can be endogenous, and (iii) no assumptions are imposed on the marginal distribution of the measurement error, so that I do not need to assume the accuracy of the measure- ment. Based on the partial identification result, I provide a consistent confidence interval for the local average treatment effect with uniformly valid size control. I also show that the identification strategy can incorporate repeated measurements to narrow the identified set, even if the repeated measurements themselves are endoge- nous. Using the the National Longitudinal Study of the High School Class of 1972, I demonstrate that my new methodology can produce nontrivial bounds for the return to college attendance when attendance is mismeasured and endogenous.

The second chapter, which is a part of a coauthored project with Federico Bugni, considers the problem of inference in dynamic discrete choice problems when the structural model is locally misspecified. We consider two popular classes of estimators for dynamic discrete choice models: K-step maximum likelihood estimators (K-ML) and K-step minimum distance estimators (K-MD), where K denotes the number of policy iterations employed in the estimation problem. These estimator classes include popular estimators such as Rust (1987)’s nested fixed point estimator, Hotz and Miller (1993)’s conditional choice probability estimator, Aguirregabiria and Mira (2002)’s nested algorithm estimator, and Pesendorfer and Schmidt-Dengler (2008)’s least squares estimator. We derive and compare the asymptotic distributions of K- ML and K-MD estimators when the model is arbitrarily locally misspecified and we obtain three main results. In the absence of misspecification, Aguirregabiria and Mira (2002) show that all K-ML estimators are asymptotically equivalent regardless of the choice of K. Our first result shows that this finding extends to a locally misspecified model, regardless of the degree of local misspecification. As a second result, we show that an analogous result holds for all K-MD estimators, i.e., all K- MD estimator are asymptotically equivalent regardless of the choice of K. Our third and final result is to compare K-MD and K-ML estimators in terms of asymptotic mean squared error. Under local misspecification, the optimally weighted K-MD estimator depends on the unknown asymptotic bias and is no longer feasible. In turn, feasible K-MD estimators could have an asymptotic mean squared error that is higher or lower than that of the K-ML estimators. To demonstrate the relevance of our asymptotic analysis, we illustrate our findings using in a simulation exercise based on a misspecified version of Rust (1987) bus engine problem.

The last chapter investigates the causal effect of the Omnibus Budget Reconcil- iation Act of 1993, which caused the biggest change to the EITC in its history, on unemployment and labor force participation among single mothers. Unemployment and labor force participation are difficult to define for a few reasons, for example, be- cause of marginally attached workers. Instead of searching for the unique definition for each of these two concepts, this chapter bounds unemployment and labor force participation by observable variables and, as a result, considers various competing definitions of these two concepts simultaneously. This bounding strategy leads to partial identification of the treatment effect. The inference results depend on the construction of the bounds, but they imply positive effect on labor force participa- tion and negligible effect on unemployment. The results imply that the difference- in-difference result based on the BLS definition of unemployment can be misleading

due to misclassification of unemployment.

Measuring Tail Risks at High Frequency

I develop a new methodology for measuring tail risks using the cross section of bid-ask spreads. Market makers embed tail risk information into spreads because (1) they lose to arbitrageurs when changes to asset values exceed the cost of liquidity and (2) underlying price movements and potential costs are linear in factor loadings. Using this insight, simple cross-sectional regressions relating spreads and trading volume to factor betas can recover tail risks in real time for priced or non-priced return factors. The methodology disentangles financial and aggregate market risks during the 2007-2008 Financial Crisis; anticipates jump risks associated with Federal Open Market Committee announcements; and quantifies a sharp, temporary increase in market tail risk before and throughout the 2010 Flash Crash. The recovered time series of implied market risks also aligns closely with both realized market jumps and the VIX.

Bewegungsklassifikation mithilfe mobiler Sensoren

In diesem Beitrag wird eine neue Methode zur Analyse des manuellen Kommissionierprozesses vorgestellt, mit der u. a. die Kommissionierzeitanteile automatisch erfasst werden können. Diese Methode basiert auf einer sensorgestützten Bewegungsklassifikation, wie sie bspw. im Sport oder in der Medizin Anwendung findet. Dabei werden mobile Sensoren genutzt, die fortlaufend Messwerte wie z. B. die Beschleunigung oder die Drehgeschwindigkeit des Kommissionierers aufzeichnen. Auf Basis dieser Daten können Informationen über die ausgeführten Bewegungen und insbesondere über die durchlaufenen Bewegungszustände gewonnen werden. Dieser Ansatz wird im vorliegenden Beitrag auf die Kommissionierung übertragen. Dazu werden zunächst Klassen relevanter Bewegungen identifiziert und anschließend mit Verfahren aus dem maschinellen Lernen verarbeitet. Die Klassifikation erfolgt nach dem Prinzip des überwachten Lernens. Dabei werden durchschnittliche Erkennungsraten von bis zu 78,94 Prozent erzielt.

Resolved Stars' Insights into Galaxy Physics

Thesis (Ph.D.)--University of Washington, 2016-08

Estimating the effect of the 2008 financial crisis on GNI in Greece and Iceland: A synthetic control approach

The purpose of this thesis is to conduct a comparative study in order to estimate the impact of the financial crisis to the GNI of Greece and Iceland. By applying synthetic control matching (a relatively new methodology) the study intends to compare the two countries, thus deducting conclusions about good or bad measures adopted. The results indicate that in both cases the adopted measures were not the optimal ones, since the synthetic counterfactual appear to perform better than the actual Greece and Iceland. Moreover, it is shown that Iceland reacted better to the shock it was exposed. However, different characteristics of the two countries impede the application of Icelandic actions in the Greek case.

Colmeias: uma estratégia didático-pedagógica para potencializar a aprendizagem significativa através da colaboração nas redes sociais em contextos móveis

O presente trabalho procura atender as necessidades dos processos educativos da atualidade, reconhecendo que esses ocorrem numa sociedade denominada como a Sociedade da Informação (SI), num ambiente em que os aprendizes são nativos digitais. Na SI presencia-se um momento marcado por um modelo computacional móvel, no qual também é possível constatar-se a emergência de um novo paradigma educacional - a aprendizagem com mobilidade - que possibilita a integração das tecnologias móveis com os processos de ensino e de aprendizagem. Além disso, observa-se a ascensão do emprego das redes sociais na Internet (RSI) no dia a dia dos indivíduos impactando as práticas estabelecidas na SI. Nesse cenário, visando integrar a aprendizagem móvel com os recursos das RSI para promover-se uma educação mais sintonizada com o perfil atual dos estudantes, expõe-se nessa tese uma nova proposta metodológica - a Colmeias almejando dessa maneira facilitar uma aprendizagem significativa a partir de um processo colaborativo, em rede e em contextos de mobilidade. Com embasamento teórico em diversos autores, entre os quais se destacam Vygostky, Bruner e Ausubel, apoiados por Júlio Cesar Santos e Pierry Dillenbourg, salienta-se que a estratégia Colmeias representa um caminho alternativo para aqueles professores que desejam promover uma educação mais coerente com a atualidade. Nessa pesquisa ainda se apresenta a sua aplicação por meio de um estudo de caso na Matemática procurando, assim, aproximar a teoria com a prática.

The Historical Thesaurus and the sentimental language of Robert Burns

This thesis demonstrates a new methodology for the linguistic analysis of literature drawing on the data within The Historical Thesaurus of the Oxford English Dictionary (2009). Developing ideas laid out by Carol McGuirk in her book Robert Burns and the Sentimental Era (1985), this study offers a novel approach to the cultural connections present in the sentimental literature of the eighteenth century, with specific reference to Robert Burns. In doing so, it responds to the need to “stop reading Burns through glossaries and start reading him through dictionaries, thesauruses and histories”, as called for by Murray Pittock (2012). Beginning by situating the methodology in linguistic theory, this thesis goes on firstly to illustrate the ways in which such an approach can be deployed to assess existing literary critical ideas. The first chapter does this testing by examining McGuirk’s book, while simultaneously grounding the study in the necessary contextual background. Secondly, this study investigates, in detail, two aspects of Burns’s sentimental persona construction. Beginning with his open letter ‘The Address of the Scotch Distillers’ and its sentimental use of the language of the Enlightenment, and moving on to one of Burns’s personas in his letters to George Thomson, this section illustrates the importance of persona construction in Burns’s sentimental ethos. Finally, a comprehensive, evidence-based, comparison of linguistic trends examines the extent to which similar sentimental language is used by Burns and Henry Mackenzie, Laurence Sterne, William Shenstone and Samuel Richardson. This thesis shows how this new methodology is a valuable new tool for those involved in literary scholarship. For the first time in any comprehensive way the Historical Thesaurus can be harnessed to make new arguments in literary criticism.

Profesores frente a estudiantes: las dos orillas de la educación bimodal

Desde hace 6 años el grupo de investigación E-Virtual de laUniversidad de Medellín viene trabajando en la implementaciónde asignaturas bimodales en la Institución. En el 2009, con elapoyo de MEN, se implementó la modalidad a distancia conmetodología virtual en el modelo pedagógico de la Universidad.Estas nuevas experiencias llevaron al Grupo a cuestionarsesobre las características pedagógicas y didácticas a teneren cuenta cuando se combinan la educación presencial y lavirtual. Para ello se indagó con profesores y estudiantes sobresu percepción al respecto. Para la recolección de informaciónse combinaron técnicas cualitativas y cuantitativas, que hanarrojado interesantes resultados, entre ellos proceso deinducción, interacciones comunicativas, Objetos Virtuales deAprendizaje y uso de la plataforma virtual.En este artículo se darán a conocer algunos resultados de lainvestigación, cuáles han sido los aspectos positivos de estaexperiencia y cuáles son las áreas a mejorar.

Identification and characterisation of telomere regulatory and signalling pathways after induction of telomere dysfunction

Telomeres are DNA-protein complexes which cap the ends of eukaryotic linear chromosomes. In normal somatic cells telomeres shorten and become dysfunctional during ageing due to the DNA end replication problem. This leads to activation of signalling pathways that lead to cellular senescence and apoptosis. However, cancer cells typically bypass this barrier to immortalisation in order to proliferate indefinitely. Therefore enhancing our understanding of telomere dysfunction and pathways involved in regulation of the process is essential. However, the pathways involved are highly complex and involve interaction between a wide range of biological processes. Therefore understanding how telomerase dysfunction is regulated is a challenging task and requires a systems biology approach. In this study I have developed a novel methodology for visualisation and analysis of gene lists focusing on the network level rather than individual or small lists of genes. Application of this methodology to an expression data set and a gene methylation data set allowed me to enhance my understanding of the biology underlying a senescence inducing drug and the process of immortalisation respectively. I then used the methodology to compare the effect of genetic background on induction of telomere uncapping. Telomere uncapping was induced in HCT116 WT, p21-/- and p53-/- cells using a viral vector expressing a mutant variant of hTR, the telomerase RNA template. p21-/- cells showed enhanced sensitivity to telomere uncapping. Analysis of a candidate pathway, Mismatch Repair, revealed a role for the process in response to telomere uncapping and that induction of the pathway was p21 dependent. The methodology was then applied to analysis of the telomerase inhibitor GRN163L and synergistic effects of hypoglycaemia with this drug. HCT116 cells were resistant to GRN163L treatment. However, under hypoglycaemic conditions the dose required for ablation of telomerase activity was reduced significantly and telomere shortening was enhanced. Overall this new methodology has allowed our group and collaborators to identify new biology and improve our understanding of processes regulating telomere dysfunction.

Diagnóstico automático de eventos e distúrbios em unidades geradoras e usinas utilizando lógica fuzzy

The electric power systems are getting more complex and covering larger areas day by day. This fact has been contribuiting to the development of monitoring techniques that aim to help the analysis, control and planning of power systems. Supervisory Control and Data Acquisition (SCADA) systems, Wide Area Measurement Systems and disturbance record systems. Unlike SCADA and WAMS, disturbance record systems are mainly used for offilne analysis in occurrences where a fault resulted in tripping of and apparatus such as a transimission line, transformer, generator and so on. The device responsible for record the disturbances is called Digital Fault Recorder (DFR) and records, basically, electrical quantities as voltage and currents and also, records digital information from protection system devices. Generally, in power plants, all the DFRs data are centralized in the utility data centre and it results in an excess of data that difficults the task of analysis by the specialist engineers. This dissertation shows a new methodology for automated analysis of disturbances in power plants. A fuzzy reasoning system is proposed to deal with the data from the DFRs. The objective of the system is to help the engineer resposnible for the analysis of the DFRs’s information by means of a pre-classification of data. For that, the fuzzy system is responsible for generating unit operational state diagnosis and fault classification.

Cascade hydropower capacity increase profitability analysis with optimisation modelling

The electricity market and climate are both undergoing a change. The changes impact hydropower and provoke an interest for hydropower capacity increases. In this thesis a new methodology was developed utilising short-term hydropower optimisation and planning software for better capacity increase profitability analysis accuracy. In the methodology income increases are calculated in month long periods while varying average discharge and electricity price volatility. The monthly incomes are used for constructing year scenarios, and from different types of year scenarios a long-term profitability analysis can be made. Average price development is included utilising a multiplier. The method was applied on Oulujoki hydropower plants. It was found that the capacity additions that were analysed for Oulujoki were not profitable. However, the methodology was found versatile and useful. The result showed that short periods of peaking prices play major role in the profitability of capacity increases. Adding more discharge capacity to hydropower plants that initially bypassed water more often showed the best improvements both in income and power generation profile flexibility.

Diagnóstico ecotoxicológico dos efluentes lançados no complexo estuarino do Jundiaí/Potengi, Natal/RN

Untreated effluents that reach surface water affect the aquatic life and humans. This study aimed to evaluate the wastewater s toxicity (municipal, industrial and shrimp pond effluents) released in the Estuarine Complex of Jundiaí- Potengi, Natal/RN, through chronic quantitative e qualitative toxicity tests using the test organism Mysidopsis Juniae, CRUSTACEA, MYSIDACEA (Silva, 1979). For this, a new methodology for viewing chronic effects on organisms of M. juniae was used (only renewal), based on another existing methodology to another testorganism very similar to M. Juniae, the M. Bahia (daily renewal).Toxicity tests 7 days duration were used for detecting effects on the survival and fecundity in M. juniae. Lethal Concentration 50% (LC50%) was determined by the Trimmed Spearman-Karber; Inhibition Concentration 50% (IC50%) in fecundity was determined by Linear Interpolation. ANOVA (One Way) tests (p = 0.05) were used to determinate the No Observed Effect Concentration (NOEC) and Low Observed Effect Concentration (LOEC). Effluents flows were measured and the toxic load of the effluents was estimated. Multivariate analysis - Principal Component Analysis (PCA) and Correspondence Analysis (CA) - identified the physic-chemical parameters better explain the patterns of toxicity found in survival and fecundity of M. juniae. We verified the feasibility of applying the only renewal system in chronic tests with M. Juniae. Most efluentes proved toxic on the survival and fecundity of M. Juniae, except for some shrimp pond effluents. The most toxic effluent was ETE Lagoa Aerada (LC50, 6.24%; IC50, 4.82%), ETE Quintas (LC50, 5.85%), Giselda Trigueiro Hospital (LC50, 2.05%), CLAN (LC50, 2.14%) and COTEMINAS (LC50, IC50 and 38.51%, 6.94%). The greatest toxic load was originated from ETE inefficient high flow effluents, textile effluents and CLAN. The organic load was related to the toxic effects of wastewater and hospital effluents in survival of M. Juniae, as well as heavy metals, total residual chlorine and phenols. In industrial effluents was found relationship between toxicity and organic load, phenols, oils and greases and benzene. The effects on fertility were related, in turn, with chlorine and heavy metals. Toxicity tests using other organisms of different trophic levels, as well as analysis of sediment toxicity are recommended to confirm the patterns found with M. Juniae. However, the results indicate the necessity for implementation and improvement of sewage treatment systems affluent to the Potengi s estuary

EL PORTAFOLIO ELECTRÓNICO: UNA OPCIÓN METODOLÓGICA

La perspectiva del portafolio supone una estrategia metodológica evaluativa guiada con objetivos previamente establecidos, la utilización del portafolio electrónico en la Escuela de Bibliotecología y Documentación de la Universidad Nacional de Costa Rica, significa que los estudiantes recolectarán intencionalmente un conjunto de evidencias donde demostrarán su propio aprendizaje con el objetivo de dar a conocer sus habilidades, destrezas, competencias, intereses, juicios de valor, entre otros, a los miembros de su comunidad educativa. Estas evidencias serán presentadas por medio de archivos y recursos digitales. Por otra parte, la aplicación y uso de esta estrategia metodológica es abierta a cualquier disciplina que quiera implementarlo, un ejemplo, lo es la Escuela de Literatura y Ciencias del Lenguaje, con el curso de literatura Francesa II cuyos resultados fueron exitosos desde su planteamiento conceptual. La integración de esta metodología por parte de los docentes y de los estudiantes tiene logros significativos para el desarrollo integral del aprendizaje y la forma de aprender significativamente.  

Lanbide heziketako irakasleen prestakuntza konpetentziak garatzeko metodologietan: Ikaskuntza Agertoki Berriak esperientziaren azterketa

[EU]XX. mendearen azken bi hamarkadetatik hona jendartean gertatu diren aldaketek, Lanbide Heziketaren (lan merkatura bideratzeko langileen prestakuntza oinarri duen heziketaren epe gisara ulertuta) planteamendua birpentsatu beharra ekarri dute. Dinamikoa eta aldakorra den jendarte honetan, Lanbide Heziketari bere hezkuntza jardueraren gaineko gogoeta egin beharra suertatu zaio, eta baita zer eta nola irakatsi lanbidea garatzea helburu duten ikasleei bezalako galderei erantzuna eman ere. Ingurumari honetan konpetentzia kontzeptua eta haren inguruko esperientziak eta metodoak garatu dira hala nazioartean nola Euskal Herrian. Master Bukaerako lan honetan Lanbide Heziketan aurrera eraman den irakasleen etengabeko prestakuntza programa baten azterketa egin dugu. Horretarako, berrikuntza eta kalitatea sustatzeko zeregina duen Tknika zentroak zuzendu eta gidatutako Ikaskuntza Agertoki Berriak prestakuntza programan parte hartu duen Tolosaldeko Lanbide Institutua aukeratu dugu, kasu azterketaren ikuspegia erabiliz. Azken xedea, laburki, irakasleei konpetentzietan oinarritutako ikaskuntza aukera didaktikoak eskaini eta haiei buruzko gogoeta egitea da, gero praktikara eraman ditzaten. Gure ikerlanaren helburua, berriz, programa horren asmoak praktikan nola ebazten eta gauzatzen diren ikustea da, prozesuan engaiatuta dauden pertsonen bizipenetatik abiatuta. Hurbilketa kualitatibo eta interpretatibo honetatik lau irakasle elkarrizketatu ditugu eta haien igurikapen, kezka eta bestelakoak jasotzen saiatu gara. Ondorio nagusienak, honakoak: (i) konpetentzien bidezko irakaskuntza-ikaskuntzaren potentziala oso nabarmena dela ikusten dutela elkarrizketatuek, (ii) gogo eta motibazio handia dutela, (iii), ikastetxean, euren egunerokoan, zailtasun eta oztopo andana topatzen dutela, (iv) zailtasunak kasu batzuetan metodologia berari dagozkion arren beste askotan ikasleak eurek ez dutela aldaketarako borondate handirik atzematen da.

Polymer microspheres: synthesis, characterisation and post-functionalisation by olefin metathesis

Porous polymer particles are used in an extraordinarily wide range of advanced and everyday applications, from combinatorial chemistry, solid-phase organic synthesis and polymer-supported reagents, to environmental analyses and the purification of drinking water. The installation and exploitation of functional chemical handles on the particles is often a prerequisite for their successful exploitation, irrespective of the application and the porous nature of the particles. New methodology for the chemical modification of macroreticular polymers is the primary focus of the work presented in this thesis. Porous polymer microspheres decorated with a diverse range of functional groups were synthesised by the post-polymerisation chemical modification of beaded polymers via olefin cross metathesis. The polymer microspheres were prepared by the precipitation polymerisation of divinylbenzene in porogenic (pore-forming) solvents; the olefin cross-metathesis (CM) functionalisation reactions exploited the pendent (polymer-bound) vinyl groups that were not consumed by polymerisation. Olefin CM reactions involving the pendent vinyl groups were performed in dichloromethane using second-generation Grubbs catalyst (Grubbs II), and a wide range of coupling partners used. The results obtained indicate that high quality, porous polymer microspheres synthesised by precipitation polymerisation in near-θ solvents can be functionalised by olefin CM under very mild conditions to install a diverse range of chemical functionalities into a common polydivinylbenzene precursor. Gel-type polymer microspheres were prepared by the precipitation copolymerisation reaction of divinylbenzene and allyl methacrylate in neat acetonitrile. The unreacted pendent vinyl groups that were not consumed by polymerisation were subjected to internal and external olefin metathesis-based hypercrosslinking reactions. Internal hypercrosslinking was carried out by using ring-closing metathesis (RCM) reactions in toluene using Grubbs II catalyst. Under these conditions, hypercrosslinked (HXL) polymers with specific surface areas around 500 m2g-1 were synthesised. External hypercrosslinking was attempted by using CM/RCM in the presence of a multivinyl coupling partner in toluene using second-generation Hoveyda-Grubbs catalyst. The results obtained indicate that no HXL polymers were obtained. However, during the development of this methodology, a new type of polymerisation was discovered with tetraallylorthosilicate as monomer.