The purposes of this study are to examine migration disparities in primary, onward, and return migration by Hispanics, non-Hispanic black, and non-Hispanic white and to inspect the differences among the various types of migration. In addition, this study explores explanations of the migration disparities. These have been rarely studied because of a lack of proper migration data. This research employs the National Longitudinal Study of Youth (NLSY79) for a logistic regression of primary migration and for a hierarchical generalized linear model (HGLM) of the two types of repeat migration, namely onward and return. The results demonstrate that whites are more likely to make primary and onward migrations compared to blacks and Hispanics. But, with return migration, significant differences between whites and other minorities are not found. With respect to the contributors or explanations, this study indicates that the racial/ethnic migration disparities are not explained by socioeconomic status as opposed to explanations by human capital perspectives. The racial/ethnic disparities in migrations seem to be produced by discrimination and an unequal distribution of opportunities. Return migration presents several interesting different patterns compared with the other type migrations, including the effects of age and educational attainment. For return migration, old and less educated individuals have higher odds, showing reversed pattern of total, primary, and onward migration. The findings seem to indicate that different characteristics are involved in different types of migration.

Cette thèse presente des travaux et résultats d'expériences de fracturation dont l'origine est une génération interne de fluides induite par des réactions chimiques dans des échantillons de roches et des matériaux analogues. Les deux premiers articles portent sur une expérience avec des échantillons de schistes imagés par tomographie aux rayons X au cours du temps. Le premier article décrit la formation de fractures créées par l'augmentation de pression induite par la décomposition de matière organique lorsque les schistes sont chauffés. Le deuxième article porte sur la procédure expérimentale et l'analyse d'images, utilisées pour obtenir les résultats du premier article. Les deux autres articles concernent la fracturation d'une couche de gélatine contenant de la levure et du sucre, ce qui génère du CO2. Le troisième article décrit le mécanisme de formation d'un réseau de fractures au cours du drainage du CO2 contenu dans la gélatine. Le quatrième article concerne l'évolution du réseau de fractures au cours de ce drainage, ainsi que les mécanismes d'ouverture et fermeture des fractures. Le dernier article porte sur une étude par tomographie aux rayons X de la distribution de porosité d'échantillons endommagés d'andésite. Les méthodes développées dans ce projet peuvent s'appliquer à la déshydratation de sédiments, la formation de volcans de boue, l'exploration d'hydrates de méthane, la séquestration de CO2 et la fracturation de réservoirs non conventionnels. / This thesis presents the experimental work and the results on fracturing of rock samples and analogue materials due to internal fluid generation during chemical reaction. The first two papers concentrate on time-resolved 3D X-ray imaging experiment on organic-rich shale samples. Paper 1 describes fracture formation due to hydrocarbon generation in the shale induced by organic matter decomposition during heating. Paper 2 gives an overview of the experimental procedure and image analysis workflow, which were used to obtain results presented in the first paper. The other two papers are focused on fracturing of gelatin mixed with yeast and sugar, which generates CO2. Paper 3 describes the mechanism of fracture network formation during draining of CO2 out of a gelatine layer. Paper 4 focuses on the temporal evolution of the drainage network and the mechanism of fracture opening and closing. The last paper presents a study in which X-ray microtomography was used to characterize porosity distribution in weathered andesite samples. The scientific methods developed in this project have potential application in studying dehydration of sediments, formation of mud volcanoes, methane hydrate exploration and assessment, geological sequestration of carbon dioxide CO2 and hydraulic fracturing of unconventional reservoirs.

本研究運用多元資料，自不同面向揭露臺灣原住民的遷徙樣貌，並連結遷徙與原住民個人社會地位取得的關連。藉遷徙多層次社會鑲嵌的特質，以解開原住民頻繁遷徙但並未對等呈現向上社會流動的弔詭。本研究同時檢視原住民族於臺灣大社會的位置，包含其空間分布、流動趨勢及其社會經濟地位。研究主要發現如下：（1）歷經卅年的遷移，原住民族大量移徙西半部，並集中在三大都會區，不同遷徙類型在各區域形成流動體系，以北部體系及東部體系擁有較大的遷徙流量；（2）原住民族較一般民眾更易集中在中低度現代化區域，主要係往都會區周邊移動，臺北縣與桃園縣對初級與連續遷徙有極大的拉力；（3）原住民族與一般民眾的遷徙模式相近，遷徙主要是朝鄰近區域與核心縣市移動，但原住民族重複遷徙行為較為獨特，連續遷徙與回流遷徙呈相反的流動；（4）自遷徙決策模型可發現，遷徙受多重因素影響，除工作要素外，家庭居住安排、生命階段的居住區位、區域性資本、社會網絡與遷徙成本及預算皆會影響其遷徙決策；長遠而言，遷徙有助於個人取得教育資源、提升社經地位，無力遷徙者與遷徙者間貧富差距逐漸拉大；（5）與理論預期相反，初級與回流遷徙對個人地位取得具正面效益，連續遷徙則為負向作用，此與原住民族社會網絡有限鑲嵌及累積資本困難所致；（6）隨著人口移動，原居地與移入地社群重組，原居地經歷了人口老化、祖孫家庭增加、傳統部落秩序瓦解，移入地蓬勃的制度化社群組織、族群聚落、同鄉會與協進會扮演都市原住民與原鄉的橋樑，遷徙所生成的脈絡亦將影響後續移動者的社會處境。奠基以上研究發現，提出政策建議與未來研究方向。 / Mainly based on a variety of data, this research aims to study several aspects of migration of Taiwan aborigines and to explore the association and causal relationship between migration and the advance of socioeconomic status. This study is originally inspired from an observed paradox that, according to the theoretical expectation and a body of existing empirical evidences, it has long been confirmed that migration is an effective means of promoting individual social mobility and lifetime wellbeing; nevertheless, the fact that the Taiwan aborigines are associated with lower socioeconomic status does not fit the fact of Taiwan aborigines being more mobile than the ordinary people. The purposes of this dissertation are (1) to characterize migration types and pattern of Taiwan aborigines, including spatial pattern, migration and mobility tendency and likelihood, and their social economic status, (2) to distinguish determinants of aborigine migration, and (3) to examine the outcome of migration whether it helps or stumbles the advance of aborigine’s socioeconomic status and mobility. Main findings are as follows: (1) in the past three decades, voluminous aborigines migrated to the western urbanized area, with the three major metropolitan areas of Taiwan as the major destination for aborigine migrants; it also forms migratory system in each area, with northern Taiwan and eastern Taiwan gaining the most number of migrants; (2) Although metropolitan areas serve as major destination for aborigine migrants, the study finds that they tend to concentrate more on the periphery than on the core area. Both counties of Taipei and Taoyuan are very attractive for primary and onward migrants; (3) the migration pattern of ordinary people is similar to that of aborigines. People usually tend to move to neighborhood and the core city. In addition, repeat migration is much more noteworthy than its primary counterpart, and onward migration is totally opposite to return migration; (4) The model of aboriginal migration indicates that migration is affected by various factors. The most salient ones include work status, living arrangement, attributes of residential location, location-specific capital, ethnic network, and availability of migration budget. Because migration help acquire educational resources and improve one’s socioeconomic status, the gap between migrants and people who are not capable of making migration will become exaggerated; (5) in opposition to theoretical expectation, primary and return migrations exhibit positive effect on the improvement of individual socioeconomic status, whereas onward migration should have negative effect. This finding is not counter to various schools of migration theory, rather, it reflects a result of limited embedded inter- and intra-ethnic network and barriers of capital accumulation; (6) migration affects both communities of origin and destination. Aging population, increasing grandparent-grandchild family, collapsing tribal authority become prevalent in original community; on the other hand, flourishing ethnic enclaves, associations, and institutionalized organizations connect urban and hometown in destination community. The context which migration results from is changed by migration itself and further affects the situation of subsequent migrants. According to empirical findings, the dissertation further suggests corresponding policy implications and proposes future research direction.