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This study was conducted to test the hypothesis that dietary supplementation with L-arginine during early pregnancy will ameliorate embryonic loss in pigs. Gilts were bred at the second estrus, and housed individually in pens and fed twice daily 1 kg of a corn- and soybean meal-based diet supplemented with 0.0%, 0.4%, or 0.8% L-arginine (w/w) between d 0 and 25 of gestation (Experiment 1) or between d 14 and 25 of gestation (Experiments 2 and 3). At d 25 (Experiment 1 and 2) or d 60 (Experiment 3) of gestation, gilts were hysterectomized to obtain uteri and conceptuses. Total RNA and protein were extracted from the frozen tissues. Quantitative RT-PCR, western blotting, and microarray analyses were performed to determine the changes of gene expression at mRNA and protein levels. Dietary supplementation with 0.8% L-arginine between d 0 and 25 of gestation decreased uterine weight, total number of fetuses, number of corpora lutea (CL), total fetal weight, total volume of allantoic and amniotic fluids, concentrations of progesterone in maternal plasma and allantoic fluid, compared to the control group. However, dietary supplementation with 0.4% or 0.8% L-arginine between d 14 and 25 of gestation increased total volume of amniotic fluid, total amounts of arginine in allantoic and amniotic fluids, total amounts of fructose and most amino acids in amniotic fluid, placental growth, and the number of viable fetuses per litter by 2. Dietary supplementation with 0.4% or 0.8% L-arginine between d 14 and 25 of gestation increased the total number of fetuses and number of live fetuses, rate of embryonic survival, and volumes of allantoic and amniotic fluids in gilts with 15 to 18 CL on d 60 of gestation compared with the control group. The abundance of placental protein and expression of mRNA related to the genes for arginine transport and metabolism, including cationic amino acid transporter 1, endothelial nitric oxide synthase (NOS3), phosphorylated-NOS3, ornithine decarboxylase, and guanosine triphosphate cyclohydrolase-I was increased by dietary supplementation with 0.8% L-arginine between d 0 and 25 of gestation. The abundance of total and phosphorylated mechanistic target of rapamycin was also enhanced by dietary 0.8% L-arginine supplementation between d 0 and 25 of gestation. Microarray analysis revealed that supplementation with 0.8% arginine between d 14 and 25 of gestation affected placental expression of 575 genes. Findings from the current study not only advance basic knowledge of mammalian reproductive biology, but also have important implications for developing practical means to enhance fertility in female pigs.

<p>\abstract</p><p>{\em Mechanism design} studies optimization problems taking into accounts of the selfish agents. {\em Network externality} is the effect a consumer receives from other consumers of the same good. This effect can be negative or positive. We first consider several mechanism design problems under the network externality assumption. The externality model used in this dissertation is more general than the widely used cardinality based model. In particular the network we consider in this dissertation is a graph, which is not necessarily complete. Our goal is to design {\em truthful} mechanisms to maximize the seller's revenue. Our main results under the network externality utility model are several optimal or near optimal mechanisms for {\em digital goods auctions}. To do so we invent several novel approximation schemes as well as applying results from the {\em approximation algorithm} literature. In particular when the agents exhibit negative network externality, we first model the problem as a two staged {\em pricing game}. We then show that the pricing game is an exact {\em potential game} which always admits a pure {\em Nash Equilibrium}. We then study the {\em best} and {\em worst} Nash Equilibrium in this game in terms of the revenue. We show two positive results. For the best Nash Equilibrium we show a $2$-approximation to the maximum revenue on bipartite graphs. For the worst Nash Equilibrium we use the notion of a {\em $\delta$-relaxed} equilibrium. In the sense that the prices for the same type of agents are within $\delta$ factor of each other. We accompany our positive results with matching hardness results. On the other hand, when the agents exhibit positive network externality, we take the {\em Myersonian} approach. We first give a complete characterization for all the truthful mechanisms. Using this characterization we present a truthful mechanism which achieves the optimal expected revenue among all the truthful mechanisms when the prior distributions of the agents are {\em independent} and {\em regular}. We also show near optimal mechanisms when the prior distributions are possibly {\em correlated}. </p><p>{\em Prior-free} auctions can approximate meaningful benchmarks for</p><p>non-identical bidders only when sufficient qualitative information</p><p>about the bidder asymmetry is publicly known.</p><p>We consider digital goods auctions where there is a {\em</p><p>total ordering} of the bidders that is known to the seller,</p><p>where earlier bidders are in some sense thought to have higher</p><p>valuations. </p><p>We define</p><p>an appropriate revenue benchmark: the maximum revenue that can be</p><p>obtained from a bid vector using prices that are nonincreasing in the</p><p>bidder ordering and bounded above by the second-highest bid. </p><p>This {\em monotone-price benchmark} is always as large as the well-known</p><p>fixed-price benchmark, so designing prior-free auctions with</p><p>good approximation guarantees is only harder. </p><p>By design, an auction that approximates the monotone-price benchmark</p><p>satisfies a very strong guarantee: it is, in particular, simultaneously</p><p>near-optimal for </p><p>essentially every {\em Bayesian} environment in which bidders'</p><p>valuation distributions have nonincreasing monopoly prices, or in</p><p>which the distribution of each bidder stochastically dominates that</p><p>of the next. Even when there is no distribution over bidders'</p><p>valuations, such an auction still provides a quantifiable</p><p>input-by-input performance guarantee. We design a simple $O(1)$-competitive prior-free</p><p>auction for digital goods with ordered bidders.</p> / Dissertation

Compliant mechanisms (CMs) take advantage of the deformation of their flexible members to transfer motion, force, or energy, offering attractive advantages in terms of manufacturing and performance over traditional rigid-body mechanisms (RBMs). This dissertation aims to advance the topology optimization (TO) technique (1) to design CMs that are more effective in performing their functions while being sufficiently strong to resist yield or fatigue failure; and (2) to design CMs from the perspective of mechanisms rather than that of structures, particularly with the insight into the concepts of joints, actuations, and functions of mechanisms. The existing TO frameworks generally result in CMs that are much like load-bearing structures, limiting the applications of CMs. These CMs (1) do not have joints, (2) are actuated by a translational force, and (3) can only do simple work such as amplifying motion or gripping. Three TO frameworks for the synthesis of CMs are proposed in this dissertation and they are summarized below. First, a framework was developed for the design of efficient and strong CMs. The widely used stiffness-flexibility criterion for CM design with TO results in lumped CMs that are intrinsically efficient in transferring motion, force, or energy but are prone to high localized stress and thus weak to resist yield or fatigue failure. Indeed, distributed CMs may have a better stress distribution than lumped CMs but have the weakness of being less efficient in motion, force, or energy transfer than lumped CMs. Based on this observation, the proposed framework rendered the concept of hybrid systems, hybrid CMs in this case. Further, the hybridization was achieved by a proposed super flexure hinge element and a design criterion called input stroke criterion in addition to the traditional stiffness-flexibility criterion. Both theoretical exploration and CM design examples are presented to show the effectiveness of the proposed approach. The proposed framework has two main contributions to the field of CMs: (1) a new design philosophy, i.e., hybrid CMs through TO techniques and (2) a new design criterion—input stroke. Second, a systematic framework was developed for the integrated design of CMs and actuators for the motion generation task. Both rotary actuators and bending actuators were considered. The approach can simultaneously synthesize the optimal structural topology and actuator placement for the desired position, orientation, and shape of the target link in the system while satisfying the constraints such as buckling constraint, yield stress constraint and valid connectivity constraint. A geometrically nonlinear finite element analysis was performed for CMs driven by a bending actuator and CMs driven by a rotary actuator. Novel parameterization schemes were developed to represent the placements of both types of actuators. A new valid connectivity scheme was also developed to check whether a design has valid connectivity among regions of interest based on the concept of directed graphs. Three design examples were constructed and a compliant finger was designed and fabricated. The results demonstrated that the proposed approach is able to simultaneously determine the structure of a CM and the optimal locations of actuators, either a bending actuator or a rotary actuator, to guide a flexible link into desired configurations. Third, the concept of a module view of mechanisms was proposed to represent RBMs and CMs in a general way, particularly using five basic modules: compliant link, rigid link, pin joint, compliant joint, and rigid joint; this concept was further developed for the unified synthesis of the two types of mechanisms, and the synthesis approach was thus coined as module optimization technique—a generalization of TO. Based on the hinge element in the finite element approach developed at TU Delft (Netherlands in early 1970), a beam-hinge model was proposed to describe the connection among modules, which result in a finite element model for both RBMs and CMs. Then, the concept of TO was borrowed to module optimization, particularly to determine the “stay” or “leave” of modules that mesh a design domain. The salient merits with the hinge element include (1) a natural way to describe various types of connections between two elements or modules and (2) a provision of the possibility to specify the rotational input and output motion as a design problem. Several examples were constructed to demonstrate that one may obtain a RBM, or a partially CM, or a fully CM for a given mechanical task using the module optimization approach.

Core executive decision-making in economic policy in the UK is dominated by a Prime Minister-Chancellor axis and a set of constraints defined by vast flows of capital around foreign exchange markets. This thesis examines policy-making during the Thatcher governments in relation to the debate about ERM membership from 1979 to 1990. The analysis reconstructs the choices which faced the Thatcher governments given their economic and European policy interests and capital accumulation priorities, and investigates core executive actors' activity against this background. From the first Thatcher administration onwards, the core executive was seriously divided on ERM membership and the government was unable to pursue a coherent policy on the issue. As a result of both a power struggle between the Prime Minister and successive Chancellors and the retention of empirically untenable policy positions by core executive actors, economic policy-making failed as a judgement about effective means to ends. In this sense, decision-making became non-rational. Having renounced the potential benefits of ERM membership for most of the 1980s, the Prime Minister and Chancellor decided to enter ERM in autumn 1990 at a central rate of DM2.95 which served neither their own interests nor those of UK producers. The failure of the Conservative government to pursue an effective policy on ERM membership represented a failure to cope with or understand the implications for successful economic management of vast capital flows around foreign exchange markets.