As of 2012, approximately 10% of the population in Colombia has been displaced by violence. The main motivation of this paper is to estimate the effect of interregional migration on employment outcomes in the country between 1993 and 2005. Using violence as an instrument for migration, I analyzed the differential effects of migration on specific employment outcomes across gender and skill levels. I find that a one percentage point increase in net migration only increases the unemployment rates of female migrants by 0.656 percentage point. I also find that net migration rates do not affect the employment conditions of low-skilled natives, even in industries with high composition of migrant workers.

Thesis (M.Sc.). / Written for the School of Computer Science. Title from title page of PDF (viewed 2009/06/30). Includes bibliographical references.

Thesis (Ph. D.)--University of California, San Diego, 2006. / Title from first page of PDF file (viewed September 20, 2006). Available via ProQuest Digital Dissertations. Vita. Includes bibliographical references.

This paper estimates the income elasticity of government pharmaceutical spending and assesses the simultaneous effect of such spending on gross domestic product (GDP). Using a panel dataset for 136 countries from 1995 to 2006, we employ a two-step instrumental variable procedure where we first estimate the effect of GDP on public pharmaceutical expenditure using tourist receipts as an instrumentforGDP. In the secondstep,weconstructanadjusted pharmaceutical expenditure series where the response of public pharmaceutical expenditure to GDP is partialled out and use this endogeneity adjusted series as an instrument for pharmaceutical expenditure. Our estimations show that GDP has a strong positive impact on pharmaceutical spending with elasticity in excess of unity in countries with low spending on pharmaceuticals and countries with large economic freedom. In the second step, we find that when the quantitatively large reverse effect of GDP is accounted for, public pharmaceutical spending has a negative effect on GDP per capita particularly in countries with limited economic freedom.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / O objetivo nesta dissertação consiste em verificar se o crescimento das exportações de produtos manufaturados chineses afetou negativamente o desempenho das exportações desses produtos dos países da América Latina, no período de 1995-2005. As exportações chinesas são consideradas em conjunto com as de Hong Kong, tendo em vista que esse país é considerado um centro de re-exportação da China. Para tal, foi estimada uma equação gravitacional ampliada para as exportações dos países latino americanos destinadas a outros mercados, incluindo como variável explicativa as exportações da China para esses destinos. O resultado obtido com a aplicação de variáveis instrumentais em dois estágios mostrou que um aumento de 1% nas exportações chinesas para esses mercados reduz as vendas externas dos países latino americanos em 0,3%. No entanto, como os instrumentos disponíveis não variam com o tempo, não foi possível utilizar o método de efeito fixo que evita o viés decorrente da omissão de varáveis que captam as características específicas dos países, as quais podem influenciar o volume de comércio. Portanto, o resultado não foi conclusivo. / The objective in this investigation consists in verify if the growth of the Chinese manufactured goods negatively affected the performance from the exports of this products from the Latin America countries, in the period 1995-2005. The Chinese exports are considerate in set with the ones of Hong Kong, since this country is considered a center of re-exportation from China. For such, was esteem a gravity equation augmented to the exportations from the Latin America countries destined to other markets, including as explicative variable the exportations from China to these destinies. The result obtained with the application of instrumental variables in two stage showed that an increase of 1% on the Chinese exports to these markets reduces the external sales from the Latin America countries in 0,3%. However, since the instruments available no change over time, it was not possible to use the method of fixed effect that avoid the bias occurred from the omission of variables, that can influence the trade volume. Thus, the result was not conclusive.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / O objetivo nesta dissertação consiste em verificar se o crescimento das exportações de produtos manufaturados chineses afetou negativamente o desempenho das exportações desses produtos dos países da América Latina, no período de 1995-2005. As exportações chinesas são consideradas em conjunto com as de Hong Kong, tendo em vista que esse país é considerado um centro de re-exportação da China. Para tal, foi estimada uma equação gravitacional ampliada para as exportações dos países latino americanos destinadas a outros mercados, incluindo como variável explicativa as exportações da China para esses destinos. O resultado obtido com a aplicação de variáveis instrumentais em dois estágios mostrou que um aumento de 1% nas exportações chinesas para esses mercados reduz as vendas externas dos países latino americanos em 0,3%. No entanto, como os instrumentos disponíveis não variam com o tempo, não foi possível utilizar o método de efeito fixo que evita o viés decorrente da omissão de varáveis que captam as características específicas dos países, as quais podem influenciar o volume de comércio. Portanto, o resultado não foi conclusivo. / The objective in this investigation consists in verify if the growth of the Chinese manufactured goods negatively affected the performance from the exports of this products from the Latin America countries, in the period 1995-2005. The Chinese exports are considerate in set with the ones of Hong Kong, since this country is considered a center of re-exportation from China. For such, was esteem a gravity equation augmented to the exportations from the Latin America countries destined to other markets, including as explicative variable the exportations from China to these destinies. The result obtained with the application of instrumental variables in two stage showed that an increase of 1% on the Chinese exports to these markets reduces the external sales from the Latin America countries in 0,3%. However, since the instruments available no change over time, it was not possible to use the method of fixed effect that avoid the bias occurred from the omission of variables, that can influence the trade volume. Thus, the result was not conclusive.

M.Sc. / In this study we consider the problem ofestiniating the slope in the simple linear errors-in-variables model. There are two different types of relationship that can he specified in the errors-in-variables model: one that specifies a functional linear relationship and one describing a structural linear relationship. The different relationship specifications can lead to different estimators with different properties. These two specifications are highlighted in this study. A least squares solution (to the estimation of the slope) is given. The problem of finding the maximum likelihood solution to these two specifications is addressed. It is noted that an unidentifiability problem arises in this attempt. The solution is seen to lie in making assumptions on the error variances. Interval estimation for the slope parameter is discussed. It is noted that any interval estimator of the slope whose length is always finite will have a confidence coefficient of zero. Various interval estimation methods are reviewed but emphasis is mainly on the investigation of a bootstrap procedure for estimating the confidence interval for the slope parameter β. More specifically, the Linder and Babu (1994) (bootstrap) method for the structural relationship model with known variance ratio is investigated here. The error distributions were assumed normal. A simulation study based on this paper is carried out. The results in the simulation study show that this bootstrap procedure performs well in comparison with the normal theory estimates for normally distributed data, that is, it has better coverage accuracy than the normal approximation.

Considering an individual’s day-to-day variability of activity-travel patterns will provide a more complete description of how an individual behaves to adapt the changing constraints and resources on different days. Without this day-to-day variability understanding, the individual’s behaviour would not be fully grasped and any suggested policy, planning and development would not completely achieve their desired objectives. The day-to-day behaviour is a subject to an interaction between individual’s needs and time-space constraints. The availability of ‘external’ resources (e.g., disposable income, built environment accessibility, and access to different travel mode/s) gives more opportunities for some individuals to participate in certain activities and/or trips than others. The constraints do not only consider budget and time constraints, but also include how an individual associates with other individuals and materials, and complies with any given authorities’ rules and regulations. The needs-constraints interaction also unveils some endogeneities which may not be captured by microeconomic and attitude theories. Failing to understand these interactions will underestimate the individual’s complex decision making process for performing certain behaviour. The constraints are not solely about physical constraints and instrumental factors, such as travel mode availability, time and cost. It is also influenced by individual’s non-instrumental variables, such as motivation, volition and habits. Currently there is a lack of knowledge how these non-instrumental variables are interacting and influencing the constraints to shape the individual’s travel behaviour. The implementation of certain activity-travel policy which only focuses in giving more opportunities to an individual within time and space resources without considering an individual’s attitude and/or habit may not be well accepted and followed by member of public. Moreover, the integration also reveals how an individual puts different priority on different potential activities based on the how an individual allocates/does not allocate time in engaging certain activities when having strong commitment and intention. In addition, including an individual’s health condition in the analysis may help in coordinating certain public health related policy with activity-travel policy. This thesis includes six papers which investigated the factors described above. The first three papers investigated how activity participation and built environment variables which can represent individuals’ constraints explain the day-to-day variability of individuals’ behaviours. Furthermore, the fourth and fifth paper explored the interaction between individuals’ time-use and activity participation, subjective characteristics and health factors. Lastly, the sixth paper examined how the time-space constraints and health condition explain the degree of variability in individuals’ multi-facet and multi-dimensional activity-travel patterns using sequential alignment method. / Genom att ta hänsyn till den dagliga variationen i en individs aktivitets- och resemönster erhålls en mer komplett bild av hur denna beter sig för att anpassa sig till ändrade begränsningar och resurser under olika dagar. Utan förståelse för denna dagliga variation kan inte individens beteende helt förstås och de föreslagna policyåtgärderna, planering eller utveckling skulle inte helt uppnå sina önskade mål. Det dagliga beteendet är föremål för en interaktion mellan å ena sidan individens behov och å andra sidan begränsningar i tid och rum. Tillgång till ”externa” resurser (exempelvis disponibel inkomst eller tillgång till olika färdmedel) påverkar möjligheterna för individer att delta i aktiviteter och/eller resor. Begränsningarna gäller inte bara monetär budget eller tid, utan inkluderar även exempelvis fysisk miljö, regler och förordningar samt hur en individ kan associera med andra individer. Växelverkan mellan behov och begränsningar belyser och klargör även endogenitet som inte självklart kan fångas av mikroekonomiska och attitydteorier. Att inte ta hänsyn till dessa interaktioner kan vara att underskatta individens komplexa beslutfattandeprocess. Tid- och rumsbegränsningarna handlar uteslutande om fysiska begränsningar och instrumentella faktorer, såsom färdmedelstillgänglighet, färdtid och färdkostnad. Individens beteende påverkas även av enskilda icke-instrumentella variabler, såsom motivation, vilja och vanor. Vi har idag bristande kunskap om hur dessa icke-instrumentella variabler interagerar med och påverkar begränsningar för att forma individens resebeteende. Genomförandet av viss aktivitets- och resepolicyåtgärder som bara fokuserar på att ge fler möjligheter till en individ inom tid- och rumsresurser, utan att också ta hänsyn individens attityder och/eller vana, kan försvåra allmänhetens acceptans.  Vidare, genom att inkludera en persons hälsotillstånd i analysen kan vi få ökade insikter hur vi kan samordna hälsorelaterade policyåtgärder med aktivitets- och resepolicyåtgärder. Denna avhandling innehåller sex artiklar som undersöker de faktorer som beskrivs ovan. De tre första artiklarna undersöker dels hur begränsningarna enligt ovan förklarar den dagliga variationen av en individs aktivitetsmönster och aktivitetsrum, dels samspelet mellan en aktivitets varaktighet, den erforderliga restiden och aktivitetsrummet. De fjärde och femte artiklarna undersöker samspelet mellan individens tid- och rumsbegränsningar, subjektiva egenskaper och hälsobegränsningar. Slutligen, i den sjätte artikeln undersöks med hjälp av en metod för sekventiell gruppering (sequential alignment) hur tidsbegränsning, rumsbegränsning och hälsotillståndet förklarar variationen i individers mångfacetterade och flerdimensionella aktivitets- och resemönster. / <p>QC 20151210</p>

Background: Understanding complex psychological treatment mechanisms is important in order to refine and improve treatment. Mechanistic theories can be evaluated using mediation analysis methods. The Pacing, Graded Activity, and Cognitive Behaviour Therapy: A Randomised Evaluation (PACE) trial studied complex therapies for the treatment of chronic fatigue syndrome. The aim of the project was to study different mediation analysis methods using PACE trial data, and to make trial design recommendations based upon the findings. Methods: PACE trial data were described using summary statistics and correlation analyses. Mediation estimates were derived using: the product of coefficients approach, instrumental variable (IV) methods with randomisation by baseline variables interactions as IVs, and dual process longitudinal structural equation models (SEM). Monte Carlo simulation studies were done to further explore the behaviour of IV estimators and to examine aspects of the SEM. Results: Cognitive and behavioural measures were mediators of the cognitive behavioural and graded exercise therapies in PACE. Results were robust when accounting for correlated measurement error and different SEM structures. Randomisation by baseline IVs were weak, giving imprecise and sometimes extreme estimates, leaving their utility unclear. A flexible version of a latent change SEM with contemporaneous mediation effects and contemporaneous correlated measurement errors was the most appropriate longitudinal model. Conclusions: IV methods using interaction IVs are unlikely to be useful; designs with randomised IV might be more suitable. Longitudinal SEM for mediation in clinical trials seems a promising approach. Mediation estimates from SEM were generally robust when allowing for correlated measurement error and for different model classes. Mediation analysis in trials should be longitudinal and should consider the number and timing of measures at the design stage. Using appropriate methods for studying mediation in trials will help clarify treatment mechanisms of action and allow for their refinement, which would maximize the information gained from trials and benefit patients.

The flight testing and evaluation of collected data must be efficient during intensive flight-test programs such as the ones conducted during development of new aircraft. The aim of this thesis has thus been to produce a first version of an aerodynamic derivative estimation program that is to be used during real-time flight tests. The program is to give a first estimate of the aerodynamic derivatives as well as check the quality of the data collected and thus serve as a decision support during tests. The work that has been performed includes processing of data in order to use it in computations, comparing a batch and a sequential estimation method using real-time data and programming a user interface. All computations and programming has been done in Matlab. The estimation methods that have been compared are both built on transforming data to the frequency domain using a Chirp z-transform and then estimating the aerodynamic derivatives using complex least squares with instrumental variables.The sequential frequency domain method performs estimates at a given interval while the batch method performs one estimation at the end of the maneuver. Both methods compared in this thesis produce equal results. The continuous updates of the sequential method was however found to be better suited for a real-time application than the single estimation of the batch method. The telemetric data received from the aircraft must be synchronized to a common frequency of 60 Hz. Missing samples of the data stream must be linearly interpolated and different units of measured parameters must be corrected in order to be able to perform these estimations in the real-time test environment.