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Section builder: a finite element tool for analysis and design of composite beam cross-sectionsChakravarty, Uttam Kumar 31 March 2008 (has links)
SectionBuilder is an innovative finite element based tool, developed for analysis and design of composite beam cross-sections. The tool can handle the cross-sections with parametric shapes and arbitrary configurations. It can also handle arbitrary lay-ups for predefined beam cross-section geometries in a consistent manner. The material properties for each layer of the cross-section can be defined on the basis of the design requirements. This tool is capable of dealing
with multi-cell composite cross-sections with arbitrary lay-ups. It has also the benefit of handling the variation of thickness of skin and D-spars for beams such as rotor blades. A typical cross-section is considered as a collection of interconnected walls. Walls with arbitrary lay-ups based on predefined geometries and material properties are generated first. The complex composite beam cross-sections are developed by connecting the walls using various types of connectors. These connectors are compatible with the walls, i.e., the thickness of the layers of the walls must match with those of the connectors at the place of connection. Cross-sections are often reinforced by core material for constructing realistic rotor blade cross-sections. The tool has the ability to integrate core materials into the cross-sections. A mapped mesh is considered for meshing parametric shapes, walls and various connectors, whereas a free mesh is considered for meshing the core materials. A new algorithm based on the Delaunay refinement algorithm is developed for creating the best possible free mesh for core materials. After meshing the cross-section, the tool determines the sectional properties using finite element analysis. This tool computes sectional properties including stiffness matrix, compliance matrix, mass matrix, and principal axes. A visualization environment is integrated with the tool for visualizing the stress and strain distributions over the cross-section.
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Ekonomická analýza podniku Mlékárna Hlinsko, a.s. / Economic analysis of company Mlékárna Hlinsko, a. s.Schejbal, Jiří January 2013 (has links)
The diploma thesis focus on elaboration of economic analysis of company Mlékárna Hlinsko, a. s. The thesis includes the basic characteristics of the industries in which the company operates, including the composition of Porter's five forces model. In the thesis are used profitability ratios, leverage, activity, liquidity and capital market. At the same time, it analyzes the degree of operating leverage and impact assessment of financial leverage. To determine the incremental impact on the return on equity is used Du Pont decomposition. As part of a comprehensive evaluation were applied credibility and bankruptcy models - Altman model, Index IN05 and Index bonity. Company Mlékárna Hlinsko, a. s. was compared with relevant competitors in the market and industry averages. In conclusion of the thesis were drawn appropriate advices and recommendations for the future. The thesis is drawn up with regard to the specifics of the food industry and the connection with company Agrofert, a. s.
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POLICY INDUCED MIGRATION IN THE UNITED STATESDaniel Bonin (11114442) 22 July 2021 (has links)
<div>State and local adoption/repeal of highly polarized policies causes migration responses
both out of and into the affected region. Interpreting the responses as revealed policy pref?erences leads to the conclusion that marijuana legalization and abortion waiting periods
had been favored nationally, while gay marriage had been opposed. Policy preferences are
geographically heterogeneous, which leads to different responses across counties. From 1992-
2017, these policy changes reduced domestic migration by two percent, which is approxi?mately 20% of the total migration decline. The migration changes, via partisan sorting,
accounted for a significant share of the increased political polarization from 2012-2016 in
western, urban, and swing counties. <br></div><div><br></div><div>In cases where unmarried parents have joint physical custody of their child(ren), there
is a wide range of default relocation restrictions that depend on their state of origin. Using
IRS county-to-county migration data, demographic data from the ACS, and state relocation
restrictions gathered from divorce law websites, I study the impact of these default reloca?tion restrictions on domestic US migration. Results from both regression discontinuity and
selection on observables designs, find about 10% - 30% less migration to counties that are
outside the allowed relocation range. This migration friction is shown to strengthen from
1992 - 2012, as both joint physical custody and unmarried parents became more common,
thereby contributing to the decline in domestic US migration. <br></div><div><br></div><div>In the United States, between 2004 and 2008, 28 states increased their minimum wage;
the national minimum wage was increased in 2007. The average migration response to these
increases was a 3% change in migration away from a one dollar increase. These effects are not
distributed evenly across the population. People from more impacted demographic groups
are more likely to move away from minimum wage increases.</div>
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Exploration and development of crash modification factors and functions for single and multiple treatmentsPark, Juneyoung 01 January 2015 (has links)
Traffic safety is a major concern for the public, and it is an important component of the roadway management strategy. In order to improve highway safety, extensive efforts have been made by researchers, transportation engineers, Federal, State, and local government officials. With these consistent efforts, both fatality and injury rates from road traffic crashes in the United States have been steadily declining over the last six years (2006~2011). However, according to the National Highway Traffic Safety Administration (NHTSA, 2013), 33,561 people died in motor vehicle traffic crashes in the United States in 2012, compared to 32,479 in 2011, and it is the first increase in fatalities since 2005. Moreover, in 2012, an estimated 2.36 million people were injured in motor vehicle traffic crashes, compared to 2.22 million in 2011. Due to the demand of highway safety improvements through systematic analysis of specific roadway cross-section elements and treatments, the Highway Safety Manual (HSM) (AASHTO, 2010) was developed by the Transportation Research Board (TRB) to introduce a science-based technical approach for safety analysis. One of the main parts in the HSM, Part D, contains crash modification factors (CMFs) for various treatments on roadway segments and at intersections. A CMF is a factor that can estimate potential changes in crash frequency as a result of implementing a specific treatment (or countermeasure). CMFs in Part D have been developed using high-quality observational before-after studies that account for the regression to the mean threat. Observational before-after studies are the most common methods for evaluating safety effectiveness and calculating CMFs of specific roadway treatments. Moreover, cross-sectional method has commonly been used to derive CMFs since it is easier to collect the data compared to before-after methods. Although various CMFs have been calculated and introduced in the HSM, still there are critical limitations that are required to be investigated. First, the HSM provides various CMFs for single treatments, but not CMFs for multiple treatments to roadway segments. The HSM suggests that CMFs are multiplied to estimate the combined safety effects of single treatments. However, the HSM cautions that the multiplication of the CMFs may over- or under-estimate combined effects of multiple treatments. In this dissertation, several methodologies are proposed to estimate more reliable combined safety effects in both observational before-after studies and the cross-sectional method. Averaging two best combining methods is suggested to use to account for the effects of over- or under- estimation. Moreover, it is recommended to develop adjustment factor and function (i.e. weighting factor and function) to apply to estimate more accurate safety performance in assessing safety effects of multiple treatments. The multivariate adaptive regression splines (MARS) modeling is proposed to avoid the over-estimation problem through consideration of interaction impacts between variables in this dissertation. Second, the variation of CMFs with different roadway characteristics among treated sites over time is ignored because the CMF is a fixed value that represents the overall safety effect of the treatment for all treated sites for specific time periods. Recently, few studies developed crash modification functions (CMFunctions) to overcome this limitation. However, although previous studies assessed the effect of a specific single variable such as AADT on the CMFs, there is a lack of prior studies on the variation in the safety effects of treated sites with different multiple roadway characteristics over time. In this study, adopting various multivariate linear and nonlinear modeling techniques is suggested to develop CMFunctions. Multiple linear regression modeling can be utilized to consider different multiple roadway characteristics. To reflect nonlinearity of predictors, a regression model with nonlinearizing link function needs to be developed. The Bayesian approach can also be adopted due to its strength to avoid the problem of over fitting that occurs when the number of observations is limited and the number of variables is large. Moreover, two data mining techniques (i.e. gradient boosting and MARS) are suggested to use 1) to achieve better performance of CMFunctions with consideration of variable importance, and 2) to reflect both nonlinear trend of predictors and interaction impacts between variables at the same time. Third, the nonlinearity of variables in the cross-sectional method is not discussed in the HSM. Generally, the cross-sectional method is also known as safety performance functions (SPFs) and generalized linear model (GLM) is applied to estimate SPFs. However, the estimated CMFs from GLM cannot account for the nonlinear effect of the treatment since the coefficients in the GLM are assumed to be fixed. In this dissertation, applications of using generalized nonlinear model (GNM) and MARS in the cross-sectional method are proposed. In GNMs, the nonlinear effects of independent variables to crash analysis can be captured by the development of nonlinearizing link function. Moreover, the MARS accommodate nonlinearity of independent variables and interaction effects for complex data structures. In this dissertation, the CMFs and CMFunctions are estimated for various single and combination of treatments for different roadway types (e.g. rural two-lane, rural multi-lane roadways, urban arterials, freeways, etc.) as below: 1) Treatments for mainline of roadway: - adding a thru lane, conversion of 4-lane undivided roadways to 3-lane with two-way left turn lane (TWLTL) 2) Treatments for roadway shoulder: - installing shoulder rumble strips, widening shoulder width, adding bike lanes, changing bike lane width, installing roadside barriers 3) Treatments related to roadside features: - decrease density of driveways, decrease density of roadside poles, increase distance to roadside poles, increase distance to trees Expected contributions of this study are to 1) suggest approaches to estimate more reliable safety effects of multiple treatments, 2) propose methodologies to develop CMFunctions to assess the variation of CMFs with different characteristics among treated sites, and 3) recommend applications of using GNM and MARS to simultaneously consider the interaction impact of more than one variables and nonlinearity of predictors. Finally, potential relevant applications beyond the scope of this research but worth investigation in the future are discussed in this dissertation.
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PRÁTICAS DE APRENDIZAGEM ORGANIZACIONAL: Estudo de casos múltiplos em empresas de consultoria na cidade de São Paulo / Organizational Learning Practices: Multiple case studin in consulting companie in São Paulo CityMiyazaki, Fernando Rejani 21 March 2017 (has links)
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Previous issue date: 2017-03-21 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Organizational learning studies aim to describe and analyze forms and reasons of knowledge creation, development and using in companies, and how these processes help an organization to generate value and competitiveness in their markets. Emphasis was given to organizational learning practices in order to determine initiatives made by companies to generate an learning favorable ambience, while knowledge management practices acts to support and complement organizational learning practices, since they’re related to activities developed in consulting companies, who were focus of this study and composed the cases here described. Discussion contained in this dissertation taken as basis an qualitative and interview-based approach, using content analysis and document analysis, with two cases analyzed individually and in a cross-sectional way, and was conducted between November 2016 and January 2017 in two big consulting companies, based in São Paulo city. When comparing perceptions and statements to the companies’ public documents and to literature-based references, it concludes that the identified practices aim to give workers a set of capabilities suited to their acting in organizations, using previous experiences, best practices mapping and knowledge transferring. Clients’ diversity of profiles and acting areas demand from studied organizations a workforce who simultaneously shows certain quality standards and singularities that gives advantages to these consulting companies and, consequently, to their clients. / O estudo da aprendizagem organizacional visa descrever e analisar as formas e motivos pelos quais ocorre a geração, aprimoramento e utilização do conhecimento dentro das empresas, e como tais processos as ajudam a gerar valor e competitividade em seus mercados de atuação. Foram enfatizadas práticas de aprendizagem organizacional, para determinar as iniciativas adotadas pelas organizações na geração de ambiência propícia ao aprendizado, enquanto as práticas de gestão do conhecimento suportam e complementam aquelas de aprendizagem organizacional, por estarem relacionadas à atividade das empresas de consultoria, alvo deste estudo e que compuseram os casos descritos neste artigo. A discussão realizada utilizou uma abordagem qualitativa baseada em entrevistas, análise de conteúdo e análise documental, com dois casos analisados individualmente e de forma cruzada, sendo realizada entre novembro de 2016 e janeiro de 2017 em duas organizações de consultoria de grande porte, localizadas na cidade de São Paulo. Ao comparar percepções e depoimentos colhidos com documentos públicos das organizações estudadas e referências constantes na literatura, concluiu-se que as práticas identificadas buscam proporcionar aos colaboradores um conjunto de capacidades adequado à atuação destes nas empresas, com aproveitamento de experiências anteriores, mapeamento de melhores práticas e transferência de conhecimentos. Os múltiplos perfis de clientes e suas áreas de atuação exigem das organizações estudadas um quadro funcional que apresente simultaneamente perfis padronizados de conhecimentos por cargo ou nível hierárquico, e especialistas em determinadas vertentes do conhecimento, para atingir padrões de qualidade e singularidade e oferecer um diferencial a estas organizações de consultoria e, consequentemente, seus clientes.
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Psychological well-being, maternal-foetal bonding and experiences of Indian surrogatesLamba, Nishtha January 2018 (has links)
Over the past two decades, India has become an international hub of cross-border surrogacy. The extreme economic and cultural differences between international couples seeking surrogacy and the surrogates themselves, clinics compromising health of surrogates for profit, the stigmatisation of surrogacy in India, and the constant surveillance of these women living in a ‘surrogate house’, have raised concerns regarding the potentially negative psychological impact of surrogacy on Indian surrogates. The primary aims of the thesis were (i) to conduct a longitudinal assessment of surrogates’ psychological problems (anxiety, depression and stress) from pregnancy until several months after relinquishing the baby to the intended parents, (ii) to examine the nature of the bond formed between surrogates and the unborn baby and establish whether this prenatal bond contributes to their psychological problems, and (iii) to explore the experiences of surrogates during and post-surrogacy. Fifty surrogates were compared with a matched group of 69 expectant mothers during pregnancy. Of these, 45 surrogates and 49 compairson group of mothers were followed up 4-6 months after the birth. All surrogates were hosting pregnancies for international intended parents and had at least one child of their own. Data were obtained using standardised questionnaires and in-depth interviews and were analysed using quantitative and qualitative methods. Indian surrogates were found to be more depressed than the comparison group of mothers, both during pregnancy and after the birth. However, giving up the newborn did not appear to add to surrogates’ levels of depression. There were no differences between the surrogates and the expectant mothers in anxiety or stress during either phase of the study. The examination of risk factors for psychological problems among the surrogates showed that anticipation of stigma, experiences of social humiliation and receiving insufficient support during pregnancy were associated with higher levels of depression following the birth. With respect to bonding with the unborn child, surrogates experienced lower levels of emotional bonding (e.g. they interacted less, and wondered less about, the foetus), but exhibited higher levels of instrumental bonding (e.g. they adopted better eating habits and avoided unhealthy practices during pregnancy), than women who were carrying their own babies. Contrary to concerns, greater bonding with the unborn child was not associated with increased psychological problems post-relinquishment. All surrogates were able to give up the child. Meeting the intended parents after the birth positively contributed towards surrogates’ satisfaction with relinquishment whereas meeting the baby did not. The qualitative findings on surrogates’ experiences showed that the majority lacked basic medical information regarding surrogacy pregnancy; hid surrogacy from most people; felt positive and supported at the surrogate house; lived in uncertainty regarding whether or not they would be allowed to meet the intended parents and the baby; and did not actually get to meet them. These findings have important implications for policy and practice on surrogacy in the Global South.
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Behavior, strength and flexural stiffness of circular concrete columns reinforced with FRP bars and spirals/hoops under eccentric loading / Étude du comportement, de la capacité, et de la rigidité en flexion de colonnes circulaires en béton armé de barres et de spirales PRF chargées excentriquementMohamed, Ahmed Abdeldayem January 2017 (has links)
Abstract : Deterioration of concrete structures reinforced with steel bars can be seen daily in regions with aggressive weather as steel-corrosion problems worsen. Fiber-reinforced-polymers (FRP) reinforcement has proven its feasibility through different civil structural elements. Present guidelines for FRP structures in North-America and Europe have not yet handled axially loaded members, due to the lack of research and experiments. This research takes charge of providing experimental database as well as extensive analyses and design recommendations of circular concrete columns reinforced totally with different FRP bars and spirals/hoops (FRP-RC columns). Full-scale columns were tested under monotonic loading with different levels of eccentricity. Test variables included the eccentricity-to-diameter ratio (e/D); reinforcement type (GFRP and CFRP vs. steel); concrete strength; longitudinal and transverse reinforcement ratio; and confinement configuration. All specimens measured 305 mm diameter and 1500 mm height. Test results indicated that specimens reinforced with glass-FRP (GFRP) or carbon-FRP (CFRP) reached their peak strengths with no damages to GFRP or CFRP rebar on either side of specimens. Specimens with CFRP reinforcement (CFRP-RC) behaved very similarly to their steel counterparts, and achieved almost the same nominal axial forces. Specimens with GFRP reinforcement (GFRP-RC) exhibited, however, reduced stiffness and achieved lower nominal axial forces than their steel or CFRP counterparts. Failure of GFRP-RC and CFRP-RC specimens was dominated by concrete crushing at low levels of eccentricity (e/D ratios of 8.2% and 16.4%). Experimental strain results revealed that GFRP bars developed high levels of strains and stresses on the compression and tension sides and hence the GFRP-RC specimens could sustain constant axial load after peak for some time up to the limit of concrete crushing at higher levels of eccentricity (e/D ratios of 8.2% and 16.4%), which help to delay the full damage. At these levels, flexural–tension failure initiated in the GFRP-RC specimens resulting from large axial and lateral deformations and cracks on the tension side until secondary compression failure occurred due to strain limitations in concrete and degradation of the concrete compressive block. The failure of CFRP-RC specimens at higher levels of eccentricity (e/D ratios of 8.2% and 16.4%) was characterized as flexural–compression in which it took place in a less brittle manner. On the other hand, this research also included different studies to analyze the test results, evaluate rebar efficiency, and provide recommendations for analysis and design. It was, therefore, indicated that the axial and flexural capacities of the tested FRP-RC specimens could be reasonably predicted using plane sectional analysis, utilizing the equivalent rectangular stress block (ERSB) parameters given by the ACI 440.1R-15 or CSA S806-12. All predictions underestimated the actual strength with variable levels of conservatism ranged between 1.05 to 1.25 for the GFRP-RC specimens and between 1.20 to 1.40 for the CFRP-RC specimens. These levels were noticeably reduced to critical limits in specimens with high-strength concretes. An elaborate review was made to the available ERSB parameters in the present steel and FRP design standards and guidelines. Modified expressions of the ERSB given in ACI 440.1R-15 and CSA S806-12 were developed. The results indicated good correlation of predicted and measured strength values with enhanced levels of conservatism. Additionally, sets of axial force–bending moment (P-M) interaction diagrams and indicative bar charts are introduced, and recommendations drawn. The compressive-strength contribution of FRP reinforcement was thoroughly reviewed and discussed. The minimum GFRP and CFRP reinforcement ratios to avoid rebar rupturing were broadly examined. Finally, the flexure stiffness (EI) of the tested specimens was analytically determined and compared with the available expressions using experimental and analytical M-ψ responses. Proposed equations are developed and validated against the experimental results to represent the stiffness of GFRP-RC and CFRP-RC columns at service and ultimate levels. / La détérioration des structures en béton armé avec des barres d’armature d’acier peut être observée quotidiennement dans les régions à climat agressif. Le renforcement interne en polymères renforcés de fibres (PRF) a démontré sa faisabilité grâce à différents éléments structuraux en génie civil. Les lignes directrices actuelles pour les structures en béton armé de PRF en Amérique du Nord et en Europe n'ont pas encore gérées les sections soumises à des efforts axiaux excentrique, en raison du manque de recherches et d'expériences. Cette recherche permet d’augmenter la base de données expérimentales ainsi établir des analyses approfondies et des recommandations de conception pour les colonnes circulaires en béton armé complètement renforcées de PRF (barres et spirales). Des grandeur-nature colonnes ont été testées sous charge monotone avec différents niveaux d'excentricité. Les variables de test comprenaient le rapport excentricité / diamètre (e/D) ; le type de renfort (PRFV et PRFC comparativement à l’acier); la résistance du béton en compression; le taux d’armature longitudinal et transversal; et la configuration de l’armature de confinement. Tous les échantillons mesuraient 305 mm de diamètre et 1500 mm de hauteur. Les résultats des tests ont indiqué que les spécimens renforcés avec des PRF de verre ou des PRF de carbone atteignaient leur résistance maximale sans endommager les barres d’armature. Des deux types de renforcement, les spécimens de PRFCCFRP se comportaient de manière très similaire à leurs homologues en acier et atteignaient presque les mêmes résistances axiales. Cependant, les spécimens avec renforcement en PRFV ont présenté une rigidité réduite et des forces axiales nominales inférieures à celles de leurs homologues en acier ou en PRFC. Le mode de rupture des spécimens de PRFC et de PRFV a été dominé par l’écrasement du béton à de faibles niveaux d'excentricité (rapports e/D de 8,2% et 16,4%). Les résultats ont révélé que les barres de PRFV ont développé des niveaux élevés de déformations et de contraintes sur les faces en compression et en tension et, par conséquent, les spécimens de PRFVC pourraient supporter une charge axiale constante après la résistance ultime pendant un certain temps jusqu'à la limite de la rupture en compression du béton du noyau à des niveaux supérieurs d'excentricité (rapport e/D de 8,2% et 16,4%), ce qui contribue à retarder la dégradation. À ces niveaux, une rupture en tension a été initiée dans les spécimens de PRFV résultant à de grandes déformations axiales et latérales et des fissures du côté de la face en tension jusqu'à ce que la rupture en compression du béton. La rupture des spécimens de PRFC à des niveaux supérieurs d'excentricité (rapport e/D de 8,2% et 16,4%) a été caractérisé comme étant en compression du béton dans laquelle il s'est déroulé de manière moins fragile. D'autre part, cette recherche comprenait également différentes études pour analyser les résultats des tests, évaluer l'efficacité des barres d'armature et fournir des recommandations pour l'analyse et la conception. Il a donc été indiqué que les capacités axiales et de flexion des spécimens en PRF testées pourraient être raisonnablement prédites en utilisant une analyse en section plane, en utilisant les paramètres du bloc de contrainte rectangulaire équivalent (BCRE) donnés par l'ACI 440.1R-15 ou la CSA S806- 12. Toutes les prédictions ont sous-estimé la résistance réelle avec des niveaux de variabilité conservateur entre 1,05 et 1,25 pour les spécimens de PRFC et entre 1,20 et 1,40 pour les spécimens de PRFC. Ces niveaux ont été nettement réduits à des limites critiques dans les spécimens avec des bétons à haute résistance. Un examen approfondi a été effectué sur les paramètres du BCRE disponibles dans les normes et les directives de conception actuelles en acier et en PRF. Les expressions modifiées du BCRE fournies dans ACI 440.1R-15 et CSA S806-12 ont été développées. Les résultats indiquent une bonne corrélation entre les valeurs de résistance prédites et mesurées avec des niveaux accrus de conservatisme. La contribution de la résistance à la compression du renforcement en PRF a été soigneusement examinée et discutée. Le taux d’armature minimum de PRFV et de PRFC pour éviter la rupture de l'armature ont été largement examinés. Enfin, la rigidité en flexion (EI) des spécimens testés a été déterminée de manière analytique et comparée aux expressions disponibles dans la littérature en utilisant les réponses expérimentales et analytiques M-ψ. Les expressions modifiées de la rigidité en flexion EI apportées dans l’ACI 440.1R ont été développées et validées.
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Epidemiological applications of quantitative serum NMR metabolomics:causal inference from observational studiesWang, Q. (Qin) 10 March 2017 (has links)
Abstract
Cardiovascular diseases are the leading cause of death worldwide and type 2 diabetes is reaching a global epidemic. Epidemiological studies have identified numerous risk factors and pharmacotherapies in relation to these cardiometabolic diseases. However, the detailed molecular mechanisms of these risk factors and drug therapies generally remain incompletely understood. Elucidating the underlying molecular effects would be essential for better understanding of the disease pathogenesis and also for discovering new therapeutic targets. Quantitative serum metabolomics, which allows for simultaneous quantification of multiple circulating metabolic measures, provides a hypothesis-free approach to systematically inspect the metabolic changes in response to endogenous and exogenous stimuli. Metabolomics thus presents a valuable tool to study the detailed molecular effects of disease risk factors and drug therapies. However, current metabolomics studies are mostly conducted in small cross-sectional studies and the causal relations of the risk factors on the metabolic measures are generally unclear, providing limited public health impact. The present thesis serves as a proof-of-concept to illustrate that well-designed observational studies can be used to infer causality. With the exemplars of assessing molecular effects of two risk factors (body mass index and sex hormone-binding globulin) and two drug therapies (statins and oral contraceptives), the thesis demonstrates that an improved causal inference can be achieved in observational studies via the combination of multiple study designs, including cross-sectional, longitudinal and Mendelian randomization analysis. This robust study design approach together with metabolomics data can be also extended to study the molecular effects of other risk factors and drug therapies. With an improved molecular understanding of a wide range of risk factors and therapies, better understanding of disease pathogenesis is ensured. / Tiivistelmä
Sydän- ja verisuonitaudit ovat johtava kuolinsyy maailmassa ja tyypin 2 diabetes on saavuttamassa globaalin epidemian mittasuhteet. Epidemiologiset tutkimukset ovat löytäneet useita riskitekijöitä ja lääkehoitoja edellä mainituille yleisille taudeille. Tyypin 2 diabetekseen ja sydän- ja verisuonitauteihin liittyvät yksityiskohtaiset molekylaariset mekanismit ymmärretään kuitenkin puutteellisesti. Molekylaaristen yksityiskohtien tarkempi ymmärtäminen olisi siten erittäin merkittävää sekä tautiprosessien ymmärtämiseksi että lääkehoitojen kehittämiseksi. Seerumin kvantitatiivinen metabolomiikka mahdollistaa useiden metabolisten suureiden samanaikaisen määrittämisen verenkierrosta ja tarjoaa siten hypoteesittoman lähestymistavan sekä sisäisten että ulkoisten ärsykkeiden aiheuttamien metabolisten muutosten systemaattiseen tutkimukseen. Metabolomiikka on siten arvokas työkalu yksityiskohtaisten molekylaaristen mekanismien tutkimuksessa, olipa kyseessä taudin riskitekijät tai lääkehoito. Metabolomiikkatutkimuksia on kuitenkin pääasiassa tehty pienissä poikittaistutkimuksissa ja riskitekijöihin liittyvien metabolisten suureiden syy- ja seuraussuhteet ovat yleisesti epäselviä, josta johtuen metabolisten suureiden kansanterveydellinen sovellettavuus on ollut heikkoa. Tämä väitöskirja esittelee tutkimuskonseptin hyvin suunniteltujen havaintotutkimuksien soveltamiseksi syy- ja seuraussuhteiden arvioinnissa. Työ sisältää esimerkit kahden riskitekijän (painoindeksi ja sukupuolihormoneja sitova globuliini) ja kahden lääkehoidon (statiinit ja ehkäisypillerit) molekylaaristen vaikutusten kausaalisista tutkimuksista. Tulokset havainnollistavat, että kausaalisten johtopäätösten luotettavuutta voidaan parantaa yhdistämällä useita tutkimusasetelmia, kuten poikittais- ja pitkittäistutkimuksia sekä Mendelististä satunnaistamista. Esitettyjä luotettavia tutkimusasetelmia, yhdessä metabolomiikkadatan kanssa, voidaan laajentaa muiden riskitekijöiden ja lääkehoitojen molekylaaristen vaikutusten tutkimuksiin. Parantunut molekyylitason ymmärrys useista riskitekijöistä ja lääkehoidoista johtaa myös parempaan tautiprosessien ymmärtämiseen.
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Essays on Labor Economics and International TradeDanyang Zhang (12437343) 20 April 2022 (has links)
<p> </p>
<p>My dissertation is composed of three independent chapters in the field of labor economics and international trade. </p>
<p><br></p>
<p>The first chapter studies marriage market signaling and women’s occupation choice. Despite the general closure of gender disparities in the labor market over the past half century, occupational segregation has been stubbornly persistent. I develop a new model that explains these occupational outcomes through marriage market signaling. Vertically differentiated men have preference over women’s unobservable caregiving ability. Heterogenous women choose caregiving occupations to signal their ability to be caregivers. My model generates unique predictions on the influence of marriage market conditions on women’s occupational choices. I find empirical support for these predictions using longitudinal data on marriage rates, policy shocks to divorce laws, and shocks to the marriage market sex ratio driven by waves of immigration. </p>
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<p>The second chapter investigates Covid19 and consumer animus towards Chinese products. Covid19 has tremendously affected all areas of our lives and our online shopping behaviors have not been immune. China is the first country to report cases of Covid19 and suffers from rising animus in the U.S. In this paper, we study consumer animus towards Chinese products post Covid19 using Amazon data. We tracked all face masks sold on Amazon between Sep. 2019 to Sep. 2020, and collect product information that is available to a real consumer, including reviews. By analyzing both seller-generated (e.g., product name, description, features) and user-generated (e.g., reviews and customer Q&A) content, we collect information on the country-of-origin as well as consumer animus for the products. Under a fully-dynamic event study design, we find that the average rating drops significantly after a product is identified as made in China for the first time, while no such drop is found for products with other countries-of-origin. This negative impact is U-shaped, which quickly expands in the first five weeks, and then gradually fades out within six months. An informative-animus review affects the average rating of a Chinese product both directly (through its own rating) and indirectly (through other future ratings), with both mechanisms supported in data. We also provide strong evidence that the drop in average rating is driven by consumer animus instead of product quality. </p>
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<p>The third chapter explores how cultural transmission through international trade affects gender discrimination. In this paper, I propose that international trade helps alleviate gender discrimination. With imperfect information on workers’ ability, there is statistical discrimination towards female workers. Through international trade, culture transmits asymmetrically between firms located in countries with different gender cultures. This cultural transmission benefits women because it transmits only in one direction from more gender-equal cultures to less gender-equal cultures. I prove this by linking the Customs data to the Industrial Firms data of China in 2004, and find that Chinese firms trading with more gender-equal cultures hire a higher fraction of female workers and enjoy higher profits. Similar patterns are not found in Chinese firms trading with less gender-equal cultures. The impact of cultural transmission goes beyond the firms engaged in international trade to have spillover effects onto purely domestic firms. Comparing across skill groups, cultural transmission benefits high-skill female workers more.</p>
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Strategic Designs for Online PlatformsWeilong Wang (13900263) 10 October 2022 (has links)
<p>Platforms are now everywhere in our society. Some platforms share real-time information such that people can refer to many aspects, i.e., transportation, weather, news, etc. For example, online learning platforms can play a significant role in accelerating learning through things like providing more real-time feedback loops. Due to the recent innovation in mobile devices as well as faster networks, live streaming platforms become a new trend. Several usages of live streaming platforms are gaming experience sharing such as Twitch, or shopping experience like Amazon Live. My dissertation studies the strategic designs of different online platforms, especially how information affects users’ strategic behaviors and how it creates<br>
different market outcomes.</p>
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