No description available.

This dissertation is about an open question of cartel ratifiable conditions. My research goal is to establish a mechanism which is able to detect and explain cartels' activities. My research question in the second chapter is whether or not an efficient cartel mechanism is ratifiable in the first-price sealed-bid auction format with participation costs. R. McAfee and J. McMillan study the coordinated bidding strategies in a strong cartel, which is incentive-compatible and efficient. This chapter investigates this efficient collusive mechanism with two important conditions (1) bidders can update their information through a cartel's prior auction and (2) they have to pay participation costs to participate in seller's auction. The concept of ratifiability, introduced by P. Cramton and T. Palfrey, is applied to explore the first-price sealedbid auction with participation costs. I discovered that the efficient cartel mechanism, such as pre-auction knockout, would be ratified when either of the two conditions exists. However, this mechanism is no longer ratifiable when both conditions exist. The bidder with the highest value in the cartel would have incentive to betray, since doing so sends a credible signal of high value. Hence, the other bidders will be discouraged from participating in the seller's auction and the highest-value bidder maximizes his revenue. In the third chapter, I studied the seller's strategy when she faces a cartel in an auction mechanism. An active seller's optimal strategy is to raise the reserve price to a level that is higher than her own valuation. The collusive mechanism is sustainable even though its revenue is extracted by the higher reserve price. If the seller is authorized to change the auction mechanism, she can receive the expected payoff, prevent the formation of a ring and keep the auction efficient. Further, I presented two methods that could deter a cartel under specific conditions. One is the residual claimants method as proposed by Y. Che and J. Kim and the other is to set a positive participation cost as outlined in the first chapter. The residual claimants method can inhibit a ring in many cases, but it may have some trouble in preventing an efficient cartel mechanism when there is only one participant in the seller's auction. In the fourth chapter, I investigated how to achieve external efficiency in a repeated game. In particular, I looked into the allocation of the budgeted that allows an authority, such as the government, to differentiate collusive behavior and to expose agents to external threats. A threshold level of the budget payment is found in an incentive compatible collusive mechanism for which the government can prevent an agent from participating. In a two-stage model, I showed that if the government can boost exemption or have more budget to subsidize agents, it is less likely that a ring will be formed.

No description available.

This thesis deals with the palladium-catalyzed nucleophilic substitution of π-activated alcohols in which the C–O bond of a non-manipulated hydroxyl group is cleaved. The thesis is divided in two chapters describing two different catalytic systems. Chapter 2 describes a heterogeneous palladium-catalyzed transfer hydrogenolysis of primary, secondary, and tertiary benzylic alcohols to generate the corresponding aromatic hydrocarbons using formic acid as the hydrogen donor. A detailed mechanistic investigation of this reaction has been conducted that establish the kinetic order of each reaction component and also the deuterium kinetic isotope effects. This data provide a mechanistic picture that the hydride transfer from formic acid to palladium, and not the C–O bond cleavage, is involved in the rate-determining step and that a catalytic amount of a base promotes the transfer hydrogenolysis. Chapter 3 describes the development, mechanistic studies and synthetic scope of a homogeneous palladium-catalyzed amination of allylic alcohols. Isolation of the catalyst precursor and equilibrium studies of the palladium and π-acidic triphenylphosphite ligand show unique properties of this catalytic system. Stereochemical, kinetic, and kinetic isotope studies have been performed to provide insight into the mechanism of C–O bond cleavage of allylic alcohol and C–N bond formation catalyzed by the palladium complex. Interestingly, both O–H and C–O bond cleavages are involved in rate-determining steps.

sn-Glycerol-3-phosphate acyltransferase [G3PAT, PlsB (E.coli), EC 2.3.1.15] is an enzyme involved in glycerolipid biosynthesis, catalysing the acylation of glycerol-3-phosphate (G3P) to produce lysophosphatidic acid (LPA). Chilling tolerance in plants is linked to the acyl-group composition of membranes, which is linked to acyltransferases with a higher selectivity for unsaturated acyl-substrates. Plant soluble G3PAT is located in the chloroplast and uses acyl-acyl carrier protein (acyl-ACP) as substrate. Soluble G3PAT exhibits strong substrate selectivity for acyl-ACP, the plastidial substrate in vivo, over acyl-CoA. cDNAs encoding soluble G3PATs have previously been cloned from several plant species and both oleate-selective and non-selective forms identified. The purpose of this thesis is to study the mechanism of plastidial G3PAT and attempt to identify factors important in determining substrate selectivity. An in vitro assay has been optimised to distinguish selective and non-selective enzyme forms under physiologically relevant conditions. The assay has been adapted to determine enzyme activity with a range of acyl-ACP and acyl-CoA substrates and to measure the kinetic constants Km and Vmax. Kinetic measurements have been made on a G3PAT protein from the chilling sensitive plant squash (Cucurbita moschata) and the L261F mutant protein containing a single amino acid substitution that significantly alters substrate selectivity. The mutation was found to increase selectivity by raising Km for unsaturated acyl-substrate. Mutant squash G3PAT proteins have been investigated to determine the importance of particular regions or amino acid residues. The mutations E142A, K193S, R235S and R237S resulted in enzymes that were completely inactive. The mutations H194S and L261F altered catalytic or substrate binding characteristics without enzyme inactivation. The catalytic mechanism and order of substrate binding for squash G3PAT have been determined, the reaction was found to proceed via a compulsory-ordered ternary complex with acyl-ACP binding before glycerol-3-phosphate.

A full length cDNA clone of Brassica napus 3-oxoacyl-ACP reductase (β-ketoacyl-ACP reductase; E.C. 1.1.1.100; βKR) and the Escherichia coli gene for the same enzyme, have been over-expressed in E. coli. Both the Brassica napus seed and Escherichia coli βKR proteins have been purified by a rapid two-step, single chromatography matrix method. Glutaraldehyde cross-linking studies show the plant βKR is expressed as a tetramer and the E. coli enzyme is expressed as a dimer. The secondary structure of the two proteins was predicted via analysis of circular dichroism spectra, which also show dilution dependent unfolding of a-helical structure in the plant enzyme, a possible explanation for the dilution inactivation of βKRs. Ultrafiltration substrate binding studies and a bireactant initial velocity study show that Brassica napus βKR employs a fixed order ternary complex mechanism with NADPH binding to the enzyme first. One-dimensional western blot analysis indicates two isoforms of βKR (28 kDa and 31 kDa) in crude B. napus seed extracts. Further analysis using two- dimensional western blots demonstrates the presence of four major isoforms. Comparison with 2D blots from B. campestris suggests that one of the major isoforms has originated from that source. The crystal structure of the E. coli βKR enzyme is also discussed.

Dynamic mechanism design is an important area of multiagent systems, and commonly used in resource allocation where the resources are time related or the agents exist dynamically. We focus on a multiagent model within which the agents stay, and the resources arrive and depart. The resources are interpreted as work or jobs and are called tasks. The allocation outcome space has a special restriction that every agent can only work on one resource at a time, because every agent has a finite computational capability in reality. We propose a dynamic mechanism and analyze its incentive properties; we show that the mechanism is incentive compatible. Empirically, our dynamic mechanism performs well and is able to achieve high economic efficiency, even outperforming standard approaches if the agents are concerned about future tasks. We also introduce a static mechanism under the setting of a restricted outcome space; it is proved that the static mechanism is incentive compatible, and its computational complexity is much less than that of the standard VCG mechanism.

The use of lean, premixed combustion in gas turbines is now widespread due to their low NOx emissions. Such systems are, however, susceptible to a phenomenon called thermoacoustic instability, which occurs as a result of unstable coupling between the combustion chamber acoustics and the flame. It can lead to large amplitude pressure oscillations within a combustor at frequencies in the hundreds of hertz. These pressure oscillations can result in unacceptably large noise levels, flame blow-out, reduced performance and fatigue failure of the combustor walls. This thesis investigates two problems of particular relevance to thermoacoustic instability. (For complete abstract open document)

Thesis PlanA (M.S.)--University of Wisconsin--Stout, 2007. / Includes bibliographical references.

Thesis (Ph.D.)--Auburn University, 2007. / Abstract. Vita. Includes bibliographic references (ℓ. 78-79)