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This study investigates the macroeconomic consequences of firm-level accounting conservatism. Consistent with conditional conservatism extending to the aggregate level, I demonstrate that annual estimates of aggregate corporate profits and gross domestic product from 1929 to 2007 compiled by the U.S. Bureau of Economic Analysis are more sensitive to negative aggregate cash flow news than to positive aggregate cash flow news. Next, I estimate the dollar value impact of firm-level accounting conservatism on measurements of macroeconomic fundamentals. Finally, I show that the federal funds rate set by the U.S. Federal Reserve tends to be lower when the dollar value impact of firm-level accounting conservatism on gross domestic product measurements is larger. These results suggest that accounting can impact social welfare by altering the measurement attributes of key macroeconomic indicators and shaping monetary policy decisions which regulate the money supply and alter macroeconomic growth. / text

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Most spacecraft are designed to be maneuvered to achieve pointing goals. This is generally accomplished by designing a three-axis control system. This work explores new maneuver strategies when only two control inputs are available: (i) sequential single-axis maneuvers and (ii) three-dimensional (3D) coupled maneuvers. The sequential single-axis maneuver strategies are established for torque, time, and fuel minimization applications. The resulting control laws are more complicated than the equivalent results for three-axis control because of the highly nonlinear control switch-times. Classical control approaches lead to optimal, but discontinuous control profiles. This problem is overcome by introducing a torque-rate penalty for the torque minimization case. Alternative approaches are also considered for achieving smooth continuous control profiles by introducing a cubic polynomial multiplicative control switch smoother for the time and fuel minimization cases. Numerical and analytical results are presented to compare optimal maneuver strategies for both nominal and failed actuator cases. The 3D maneuver strategy introduces a homotopy algorithm to achieve optimal nonlinear maneuvers minimizing the torque. Two cases are considered: (i) one of the three-axis control actuators fails and (ii) two control actuators fail among four control actuators. The solution strategy first solves the case when all three actuators are available. Then, the failed actuator case is recovered by introducing a homotopy embedding parameter, ε, into the nonlinear dynamics equation. By sweeping ε, a sequence of neighboring optimal control problems is solved that starts with the original maneuver problem and arrives at the solution for the under-actuated case. As ε approaches 1, the designated actuator no longer provides control inputs to the spacecraft, effectively modeling the failed actuator condition. This problem is complex for two reasons: (i) the governing equations are nonlinear and (ii) ε fundamentally alters the spacecraft’s controllability. Davidenko’s method is introduced for developing an ordinary differential equation for the costate variable as a function of ε. For each value of ε, the costate initial conditions are iteratively adjusted so that the terminal boundary conditions for the 3D maneuver are achieved. Optimal control applications are presented for both rest-to-rest and motion-to-rest cases that demonstrate the effectiveness of the proposed algorithm.

This thesis describes an extensive investigation of the O- to C-carboxyl transfer of oxazolyl carbonates using isothioureas as Lewis base catalysts. The structural requirements of simple bicyclic amidines and isothioureas to promote this transformation have been investigated, showing that the catalytic efficiency and product distribution of these reactions are markedly affected by the catalyst structure. The optimal isothiourea catalyst was efficiently applied to the rearrangement of a wide range of oxazolyl, benzofuranyl and indolyl carbonates. The structural motif of tetrahydropyrimidine-based isothioureas has then been evaluated in order to develop an asymmetric variant of the O- to C-carboxyl transfer of oxazolyl carbonates. A number of chiral isothioureas bearing stereodirecting groups in C(2) and/or C(3) have been synthesised and used in this rearrangement, showing that a C(2)-stereodirecting unit is essential for high enantioselectivity, with an additional C(3)-substituent increasing the reactivity. The optimal chiral C(2)-substituted isothioureas identified are general and efficient asymmetric catalysts for O- to C-carboxyl transfer of oxazolyl carbonates, generating a quaternary stereocentre with high enantioselectivity (up to 94% ee). The origin of the enantioselectivity of this process has been probed mechanistically and rationalised computationally. Having gained an insight into the structural motifs of isothioureas required to impart good catalytic activity and asymmetric induction in the O- to C-carboxyl transfer of oxazolyl carbonates, the mechanism of this reaction was probed using kinetic and mechanistic experiments. ¹⁹F NMR spectroscopic analysis allowed the evolution of product, by-product and intermediate throughout the reaction to be monitored while a number of crossover and stability experiments gave additional information about the catalytic cycle. Extension to a related system has been demonstrated with the O- to C-carboxyl transfer of furanyl carbonates, producing a mixture of α- and γ-butenolides depending on the nature of the Lewis base employed. DMAP gives a mixture of both regioisomers with a preference for the α-regioisomer, while NHCs lead predominantly to the γ-regioisomer. Chiral isothioureas have been used to promote this rearrangement, giving the major α-regioisomer with good enantioselectivity (up to 83% ee). To quantify the different reactivities observed with these isothioureas, their nucleophilicities and Lewis basicities using the stopped-flow technique have been determined. Finally, model studies toward the synthesis of the natural product calcaridine A, using the methodology developed herein, have been investigated.

本文研究目的在於以Brantly Womack的不對稱關係理論，來研究兩岸關係，並測試其理論的有效性。有關不對稱關係理論，原本以經濟及軍事面向為分析焦點。本論文則將民主及主權等相關理論列入分析範疇，並使得不對稱理論的研究範圍擴大。此外，有關第三方的角色，尤其是美國的角色，也納入了論文的討論與分析。因此，不對稱關係的研究，也將從雙邊關係，拓展到三邊關係。本論文將對不對稱的三角關係，作出了理論及政策上的貢獻。 / The basic aim of this current thesis is to place the connection between China and Taiwan into Brantly Womack’s concept of asymmetric connections. The main question of the study is if the relations across the Taiwan Strait are an asymmetric one and if so, does this connection fit into the framework of the mentioned theory. The presence of non-symmetry or the lack of it is to be proven uniquely through the sectors of economy and military, by comparing the two actors in these spheres. With the step of taking these two sectors as the basis of the examination and including a democratically governed territory in the study, not just the limitations of the original concept will be broadened, but a gap will be filled that has existed in the field. Additionally, a third party, the United States is introduced into the connection between Beijing and Taipei. The nature of the study of the relations will change from bilateral to triangular. As a result, the concept of asymmetric triangle will take the place of the asymmetric connections theory for the duration of one chapter.