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Statistical Process Control (SPC) provides tools to monitor process quality and productivity. When coupled with closed loop control theory, SPC algorithms can be utilized to compensate for various error sources in stable, high volume, discrete part manufacturing processes. These error sources include environmental effects, tool wear, measurement, and material errors. Closed loop machining cells must be analyzed from both Quality and Manufacturing Engineering perspectives for efficient and successful implementation. Discrete, stochastic, time event manufacturing simulation is used to analyze process organization, data flow and control system performance. SPC and Engineering Process Control (EPC) control algorithms are compared using data gathered from a high volume machining process involving steel turned components with a critical machined surface. Master of Applied Science (MASc)

While Ethiopia is Africa’s largest livestock producer, sanitary and phytosanitary (SPS) barriers and animal diseases have traditionally constrained market access. A system dynamics model examined the feasibility of a proposed SPS certification system under a number of scenarios. Model results indicate that the system may not be viable for beef exports to Middle Eastern markets. However, the binding constraint is high domestic input costs rather than the costs of SPS compliance. Sensitivity analyses reveal that while investments in feed efficiency and animal productivity would enhance Ethiopia’s export competitiveness, the competitive nature of international beef markets may still prevent market access.

This paper examines the role of livestock products as commodities of trade, responding to the demand and higher prices that many external markets offer, and at the same time providing important contributions to the development process in poorer countries. It highlights that this opportunity is not without its threats: much of the Western world has, over the last half century in particular, invested substantial amounts of money in controlling and eradicating many infectious diseases of livestock, and in building up healthy and highly productive animals, the products derived from which earn them very large sums of money on world markets. Such countries are not willing to take risks that could threaten their livestock industries, and their domestic and export markets that maintain high animal health and food safety standards. The study builds on a number of 'success stories', examples where developing countries have succeeded in exporting livestock or livestock products to external markets. An analysis of the factors governing their success revealed some commonalities: all were driven by strong private sector partners who contributed capital, management expertise and entrepreneurial flair; most concerned livestock products, rather than live animals, which matched the market's requirements; many had developed strong brand identities which had become synonymous with quality, safety and dependability; and many were vertically integrated systems, incorporating small and medium scale out-grower producers. Often these successes have been achieved despite the absence of effective support from the public sector, such as national veterinary authorities. One of the key findings of this study is the disparity between the push for global harmonisation of animal health standards for trade, and the lack of capacity of developing countries, particularly LDCs, to meet these standards. The study considers how this might be rectified and concludes that building capacity of regional bodies to create regional centres of excellence with regard to SPS matters may be the most practical way forward.

A newly recognized disease of horses, called Potomac Horse Fever (PHF), emerged during the late 1970's in a region close to the Potomac River near Washington, D.C., United States of America. The studies which were carried out by a research group to define the epidemiology and establish the cause of the disease are described. Further studies examined the possible route of transmission of the causative organism, and the role of farm animals and wild rodents in the epidemiology of the disease. Results of a case-control study conducted in 1983 characterised the disease as a non-contagious, infectious seasonal disease of horses of all age, sex and horse-use categories. The study found a lack of association with most of the variables studied, and assisted in discounting some of the numerous aetiologies proposed at the time. The results showed positive associations with a few variables, which included the previous presence of the disease in a barn, the presence of other livestock and the presence of habitats favourable for arthropod breeding and development. The disease was established experimentally in ponies following blood transfusion from natural cases of PHF, an Ehrlichia was isolated from the white blood cells of the experimentally infected ponies and this organism subsequently reproduced the disease on inoculation into susceptible ponies. The experimental disease was consistent with that seen in field cases. Pathological studies on the disease were carried out, and the causative Ehrlichia was identified on the wall of the large intestine of affected animals. Experiments established that the intradermal route was effective in transmitting the disease to ponies. A serological survey of farm animals and wild rodents from affected farms showed no indication of previous exposure to the causative Ehrlichia in 98% of samples tested. None of the mammalian species studied appears to serve as a reservoir of the infection.

GenBank, the public repository for nucleotide and protein sequences, is a critical resource for molecular biology, evolutionary biology, and ecology. While some attention has been drawn to sequence errors (1), common annotation errors also reduce the value of this database. In fact, for organisms such as fungi, which are notoriously difficult to identify, up to 20% of DNA sequence records may have erroneous lineage designations in GenBank (2). Gene function annotation in protein sequence databases is similarly error-prone (3, 4). Because identity and function of new sequences are often determined by bioinformatic analyses, both types of errors are propagated into new accessions, leading to long-term degradation of the quality of the database. Currently, primary sequence data are annotated by the authors of those data, and can only be reannotated by the same authors. This is inefficient and unsustainable over the long term as authors eventually leave the field. Although it is possible to link third-party databases to GenBank records, this is a short-term solution that has little guarantee of permanence. Similarly, the current third-party annotation option in GenBank (TPA) complicates rather than solves the problem by creating an identical record with a new annotation, while leaving the original record unflagged and unlinked to the new record. Since the origin of public zoological and botanical specimen collections, an open system of cumulative annotation has evolved, whereby the original name is retained, but additional opinion is directly appended and used for filing and retrieval. This was needed as new specimens and analyses allowed for reevaluation of older specimens and the original depositors became unavailable. The time has come for the public sequence database to incorporate a community-curated, cumulative annotation process that allows third parties to improve the annotations of sequences when warranted by published peer-reviewed analyses (5)., (undefined)