Inaug.-diss.--München. / Bibliography: p. vi-viii.

Inaug.-diss.--München. / Bibliography: p. vi-viii.

Thesis (Ph.D.)--Bryn Mawr. / Vita. Reprinted from Trans. Am. Math. Soc., July, 1914.

archives@tulane.edu / It is well known that estimates of average treatment effects may obscure heterogeneous responses within treatment subgroups. In this dissertation, I use a common methodology—the triple differences estimator—to investigate subgroup heterogeneity within treatment cohorts. Within each chapter, I begin by using the difference-in-differences estimator to determine the average treatment effect of a natural experiment on a particular group. I then use the triple differences estimator to investigate whether subgroups within the treatment population respond differentially to the same intervention. The chapter “Fertility Responses to the 1994 Earned Income Tax Credit (EITC) Expansion” investigates whether groups that have a revealed preference for larger families respond to the EITC expansion by increasing family size. The chapter “Non-Income Behavioral Responses to the 1994 EITC Expansion” uses a similar definition for revealed preference for family size. This chapter investigates whether families who used paid tax preparers or who do not have a revealed preference for larger size respond to the EITC expansion by reducing the number of children claimed on their taxes. The fianl chapter, “Worker-level Responses to Trade Shocks”, estimates whether the welfare of certain classes of fragile manufacturing workers responds differentially to a sharp reduction and recovery in import penetration. Each chapter uncovers surprising heterogeneity that diverges from the average treatment cohort effect. Families that prefer larger families increase family size post-expansion; post-expansion, families that use paid preparers reduce large family claims. For two out of three classes of fragile workers, increases in import penetration are associated with increased wage once manufacturing output recovers from shock. As a whole, this work points to the importance of taking a second look at salient underlying differences that may necessitate varied policy solutions to a common, unexpected occurrence. / 1 / Stephanie Fortune-Taylor

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Ce travail concerne l’étude expérimentale de la sensibilité de l’écoulement du moteur et de ses variations cycle à cycle (VCC) à trois variations des conditions aux limitesliée à l’optimisation du remplissage moteur. Dans la configuration standard, l’écoulement tridimensionnel de rouleau (« tumble ») est décrit pendant les phases d’admission et de compression.Un phasage plus précoce de la loi de levée d’admission augmente le débit de masse aux soupapes et amplifie les fluctuations dès le début de l’admission. L’intensité du rouleau est beaucoup plus faible à phase mi-compression. L’énergie fluctuante au point mort haut est plus faible. Une course rallongée du moteur conduit, en fin de compression, à un basculement de l’écoulement moyen et à une évolution très différente des vitesses fluctuantes,due au confinement différent vue par l’aérodynamique du moteur. Enfin, la modification des conduits d’admission entraîne une variation de l’intensité et une structuration fondamentalement différente de l’écoulement. En outre, pour décrire le transfert vers la turbulence,deux méthodologies de classification des structures de l’écoulement en groupe par corrélation spatiale, puis par « clustering » sont adaptées. L’analyse statistique du contenu des différents groupes et des transitions entre groupes permet de montrer que les VCC sont associées à différentes trajectoires dans l’espace des groupes. Des statistiques conditionnelles sont calculées pour analyser les données de chaque groupe et permettent de définir une décomposition triple. Ces caractérisations plus précises des VCC sont très générales et applicables à des grandes bases de données expérimentales ou numériques. / This experimental work concerns a sensitivity study of the in-cylinder flow in aspark-ignition engine and of the cycle to cycle variations (CCV) by comparing three variationsof boundary conditions related to the optimisation of air filling conditions. In the reference case, the three dimensional tumble flow is characterized during the intake and compression phases. A earlier intake cam phase increases the mass flow rate at inlet valves and amplifiesthe fluctuations immediately after the start of intake phase. The tumble ratio is much lowerat mid-compression phase. The fluctuating energy at top dead center is reduced. A longerengine stroke leads, at the end of compression phase, to a shift of mean flow and to a verydistinct evolution of the fluctuating velocity, due to the different confinement from the pointof view of the engine internal flow. Finally, the modification of intake duct design changes theflow intensity and reorganizes in depth the flow structure. Moreover, to describe the transfer into turbulence, two methodologies of classification in groups of flow structures, by spatial correlation then by clustering, are proposed. A phase-averaged analysis of the statistics of group content and inter-group transitions shows that CCV can be associated with different sets of trajectories during the second half of the compression phase. The conditional statistics are computed to analyse the data in each group, which leads to a triple decomposition. It is important to point out that this more accurate evaluation of CCV is applicable to very large sets of experimental or numerical data.

Habilitationsschrift--Düsseldorf. / Bibliogr. p. 891-965. Index.

The main theorem of the thesis asserts that if B is a JB*-subtriple of a JB*triple A such that B separates oe(An U {O}, then if A or B is postliminal, A=B. The main theorem and many of the other key results of the thesis are generalisations of the results of Kaplansky (1951) and Glimm (1960) on the Stone-Weierstrass conjecture for C* -algebras. We first prove a Stone-Weierstrass theorem for postliminal JB-algebras. This plays an essential role in the proof of the main theorem and is also important in the proof of our second main result, the Glimm-Stone-Weierstrass theorem for JB-algebras. Vital to the Glimm-Stone-Weierstrass proof, we show that if A is a universally reversible prime and antiliminal JB-algebra, then S(A) C P(A). Conversely, if A is universally reversible and of dimension greater than one, S(A) C P(A) implies A is prime and antiliminal. The C* -algebra version of this theorem is due to Tomiyama and Takesaki (1961). By means of the universal enveloping C*-algebra functor, we show that if , the Stone-Weierstrass conjecture is true for C* -algebras then it is true for JB-algebras. Employing a similar technique we prove Stone-Weierstrass theorems for semi-finite JW-algebras and type I JW-algebras, building on results of Akemann (1969- 70). The crucial result of the thesis reduces the Stone-Weierstrass separation condition for JB*-triples locally to that of JB*-algebras. Using this in conjunction with the Stone-Weierstrass theorem for postliminal JB-algebras is an essential part of the proof of the main theorem

Aim and problem: Our aim with this study is to understand the dynamics on Colombian broadband market and the business opportunities arising from it. For that purpose we have formulated the following 3 research questions: 1) What characterizes the Colombian broadband market? 2) How can broadband contribute to development in Colombia? 3) Who benefits from business opportunities on the Colombian broadband market?   Method: The authors have chosen the qualitative study method in order to have better understanding, explanations and analysis of the problem. The collection of the empirical data has been conducted through interviews in Colombia.   Result & Conclusions: Research has shown that broadband  in Colombia is still under development and is present mainly in urban areas while rural areas still show a great lack of the service. Operators are offering triple play service which includes telephone, Internet and television at different speeds and prices.   The development of Broadband has a positive economic impact on the Colombian society and contributes to increase competitiveness and is a driving force for economic by stimulating productivity.   Suggestions for future research: The study has been limited to Colombian broadband market, the broadband technology and services based on broadband technology. The authors suggest for a future research to study how the expansion of broadband in rural areas in Colombia will affect the life and the businesses.   Contribution of the thesis: This study contributes to the understanding of the present situation of the broadband market in Colombia and the business opportunities open for vendors, operators and end users.

L’objet de cette recherche est la construction d’un outil de comptabilité socioenvironnementale, dans un contexte de recherche-intervention au sein d’une entreprise de l’Economie Sociale et Solidaire, par une personne appartenant à cette organisation. La visée transformative de cette intervention est l’inscription de cette organisation dans la soutenabilité forte. Le travail réalisé vise à répondre aux questions suivantes : Quel design d’outil pour répondre à ces attentes ? Existe-t-il ou faut-il le créer ? Quels éléments du contexte de l’organisation influencent son adoption ? L’objectif de transformation visé peut-il être atteint ? Si oui dans quelles conditions ? Afin d’apporter des éléments de réponses à celles-ci, le concept de soutenabilité et ses traductions comptables existantes sont examinés. La manière dont le design de l’outil influence son adoption ainsi que le potentiel transformatif d’un outil de ce type sont ensuite étudiés. N’ayant pas identifié d’outil répondant aux attentes initiales, nous avons développé un système de comptabilité triple capital sans monétarisation. Bien que ce modèle présente des limitations qui nécessitent de poursuivre les recherches, il propose une opérationnalisation du concept de soutenabilité forte des capitaux (social et environnemental) comme systèmes adaptatifs complexes. Ce faisant, il identifie les difficultés opérationnelles inhérentes à ce type de démarche. Il souligne de quelle manière la comptabilité de la soutenabilité forte est en substance une comptabilité de l’insoutenabilité des organisations, et l’impact de cette caractéristique sur la possibilité d’adoption d’un tel outil. Des leviers processuels destinés à améliorer son acceptabilité sont enfin proposés. / The purpose of this research is the construction of a socio-environmental accounting tool in a context of researchintervention, within a company of the Social Economy, by a person belonging to this organization. The transformative aim of this intervention is the inscription of this organization within strong sustainability. The aim is to answer the following questions: What tool design in order to meet these expectations? Does it exist, or does it have to be created? What elements of the organization's context influence its adoption? Can the transformation goal be achieved? If so, under what conditions? The concept of sustainability and its existing accounting translations are examined. The way in which the design of the tool influences its adoption and the transformative potential of a tool of this type are then studied. Not having identified a tool that meets the initial expectations, we developed a triple capital accounts system without monetization. Although this model has limitations that require further research, it proposes an operationalization of strong sustainability of capitals (social and environmental) as complex adaptive systems. In doing so, it identifies the operational difficulties to this type of approach. It underlines how strong sustainability accounting is essentially accounting for the unsustainability of organizations, and the impact of this feature on the adoption of such a tool. Processes to improve its acceptability are finally proposed.