Direct Laser Sintering of Metals

The use of a directed laser bealn source to selectively sinter multiple layers of binderless metal powder for the purposes of rapid prototyping is described. The work in this paper is restricted to -325 mesh iron powder, which was sintered using a C\V 50 W Nd:YAG laser to approximately 3.5% density. A subsequent post-treatlnent was perfornled to achieve a fully dense saulple. It is envisioned that such a system can be used to manufacture functional metallic prototypes directly from CAD without part-specific tooling.Mechanical Engineerin

Levels or Differences in Meat Demand Specification

We estimated a wholesale demand system for beef, pork, lamb, chicken, and turkey using quarterly U.S. data and a dynamic, CBS system (Keller and Van Driel). The CBS system is a differential system, which means that it might be more appropriately applied in those situations where the data have unit roots. If there are unit roots, differencing the data can improve the properties of the estimates. If the data do not have unit roots, differencing the data might harm the properties of the estimates. We tested the specification of the model's error terms using state-space techniques. State-space units allow one to deal with roots on the unit circle without filtering the data (See Durbin and Koopman). The demand system has only four independent error terms. The state-space model we used could have decomposed these four independent error terms into four errors with unit roots and four with 0 roots. Adding state-space features to the model greatly improved its performance as measured by the likelihood ratio statistics. The estimates imply that the raw demand data have two unit roots and three 0 roots. Our mixed approach improves the properties of the estimates.Demand and Price Analysis,

The Impact of Domestic and Import Prices on U.S. Lamb Imports: A Production System Approach

As U.S. lamb imports increased relative to domestic production, and the relative share of chilled to frozen lamb imports increased, importers of chilled lamb have become less responsive to domestic and import prices, while the direct opposite is the case for frozen lamb imports. From 1990 to 2003, chilled lamb imports from Australia and New Zealand became less and less responsive to U.S. prices, and frozen imports became more responsive. Unconditional own-price elasticities also show that, over time, imports of chilled lamb became less responsive to import prices while frozen imports became more responsive to import prices.lamb, demand, imports, trade, import demand, production, International Relations/Trade,

U.S. DEMAND FOR IMPORTED LAMB BY COUNTRY: A TWO-STAGE DIFFERENTIAL PRODUCTION APPROACH

Due to a depressed wool industry sheep inventories have been declining resulting in significant increases in lamb and mutton imports. Goals of this paper are to estimate the derived demand and output supply for U.S. lamb imports, estimate demand elasticities, and to determine the impact of TRQ reductions on imports.Demand and Price Analysis,

Tracking autophagy during proliferation and differentiation of trypanosoma brucei

Autophagy is a lysosome-dependent degradation mechanism that sequesters target cargo into autophagosomal vesicles. The Trypanosoma brucei genome contains apparent orthologues of several autophagy-related proteins including an ATG8 family. These ubiquitin-like proteins are required for autophagosome membrane formation, but our studies show that ATG8.3 is atypical. To investigate the function of other ATG proteins, RNAi compatible T. brucei were modified to function as autophagy reporter lines by expressing only either YFP-ATG8.1 or YFP-ATG8.2. In the insect procyclic lifecycle stage, independent RNAi down-regulation of ATG3 or ATG7 generated autophagy-defective mutants and confirmed a pro-survival role for autophagy in the procyclic form nutrient starvation response. Similarly, RNAi depletion of ATG5 or ATG7 in the bloodstream form disrupted autophagy, but did not impede proliferation. Further characterisation showed bloodstream form autophagy mutants retain the capacity to undergo the complex cellular remodelling that occurs during differentiation to the procyclic form and are equally susceptible to dihydroxyacetone-induced cell death as wild type parasites, not supporting a role for autophagy in this cell death mechanism. The RNAi reporter system developed, which also identified TOR1 as a negative regulator controlling YFP-ATG8.2 but not YFP-ATG8.1 autophagosome formation, will enable further targeted analysis of the mechanisms and function of autophagy in the medically relevant bloodstream form of T. brucei

U.S. Demand for Source–Differentiated Shrimp: A Differential Approach

Estimates of price and scale elasticities for U.S. consumed shrimp are derived using aggregate shrimp data differentiated by source country. Own-price elasticities for all countries had the expected negative signs, were statistically significant, and inelastic. The scale elasticities for all countries were positive and statistically significant at the 1% level with only the United States and Ecuador having scale elasticities of less than one. For the most part, the compensated demand effects showed that most of the cross-price effects were positive. Our results also suggest that despite the countervailing duties imposed by the United States, shrimp demand was fairly stable.CBS, conditional demand, countervailing duty, imports, scale elasticity, shrimp, Agribusiness, Farm Management, Food Consumption/Nutrition/Food Safety, Production Economics, C32, D12, Q13, Q22,

Arbitrary precision composite pulses for NMR quantum computing

We discuss the implementation of arbitrary precision composite pulses developed using the methods of Brown et al. [Phys. Rev. A 70 (2004) 052318]. We give explicit results for pulse sequences designed to tackle both the simple case of pulse length errors and for the more complex case of off-resonance errors. The results are developed in the context of NMR quantum computation, but could be applied more widely.Comment: 16 pages elsart, no figures. In press at Journal of Magnetic resonanc

Ethical theory and stakeholder-related decisions: The role of stakeholder culture

We use convergent elements of major ethical theories to create a typology of corporate stakeholder cultures—the aspects of organizational culture consisting of the beliefs, values, and practices that have evolved for solving problems and otherwise managing stakeholder relationships. We describe five stakeholder cultures—agency, corporate egoist, instrumentalist, moralist, and altruist—and explain how these cultures lie on a continuum, ranging from individually self-interested (agency culture) to fully other-regarding (altruist culture). We demonstrate the utility of our framework by showing how it can refine stakeholder salience theory