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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

An economic analysis of gene marker assisted seedstock selection in beef cattle

Akhimienmhonan, Douglas 05 1900 (has links)
This study analyzes the economic impact of a recent gene marker innovation for seedstock selection in beef cattle. Gene markers are being developed for many beef cattle attributes; this study focused on the tenderness quality of beef using two categories: tender and tough. The study begins by describing conventional procedures for seedstock selection, the science which underlies selection by gene markers and other non-genetic procedures currently being used to improve beef tenderness. After describing the commercialization of the gene marker innovation, a stylized model of a beef supply chain is constructed. The supply chain consists of a representative consumer, a producer/processor group and a monopolist supplier of the patented technology. Welfare changes resulting from the adoption of the innovation were simulated using four sets of demand elasticity data from literatures. An important focus of this research is determining how the economic surplus from the innovation will be shared by consumers, producers and the gene marker monopolist. The consumer and gene marker monopolist benefit from the technology unless the marginal and fixed cost variables (not estimated in this study) of the monopolist, are excessively high. Producer surplus was simulated as positive with three of the four elasticity data sets. The share of surplus capture by producers is generally low relative to the gains captured by consumers and the gene marker monopolist. Comparative static analysis reveal that the benefit from the innovation varies across breeds, being higher for breeds in which the favorable form of the marker gene is more likely to be present. Despite the apparent benefits of the innovation for beef supply chain participants, reported interviews with industry scientists reveal that markers should not be viewed as a replacement for conventional selection techniques. Indeed, selecting seedstock on the basis of a small number of available markers is not likely to produce the benefits that are currently being promised by life science companies. Consequently, this study recommends that the innovation be incorporated into existing seedstock selection practices. Much more analysis is needed to understand the full economic impact of gene markers for beef tenderness and for other beef quality attributes.
2

An economic analysis of gene marker assisted seedstock selection in beef cattle

Akhimienmhonan, Douglas 05 1900 (has links)
This study analyzes the economic impact of a recent gene marker innovation for seedstock selection in beef cattle. Gene markers are being developed for many beef cattle attributes; this study focused on the tenderness quality of beef using two categories: tender and tough. The study begins by describing conventional procedures for seedstock selection, the science which underlies selection by gene markers and other non-genetic procedures currently being used to improve beef tenderness. After describing the commercialization of the gene marker innovation, a stylized model of a beef supply chain is constructed. The supply chain consists of a representative consumer, a producer/processor group and a monopolist supplier of the patented technology. Welfare changes resulting from the adoption of the innovation were simulated using four sets of demand elasticity data from literatures. An important focus of this research is determining how the economic surplus from the innovation will be shared by consumers, producers and the gene marker monopolist. The consumer and gene marker monopolist benefit from the technology unless the marginal and fixed cost variables (not estimated in this study) of the monopolist, are excessively high. Producer surplus was simulated as positive with three of the four elasticity data sets. The share of surplus capture by producers is generally low relative to the gains captured by consumers and the gene marker monopolist. Comparative static analysis reveal that the benefit from the innovation varies across breeds, being higher for breeds in which the favorable form of the marker gene is more likely to be present. Despite the apparent benefits of the innovation for beef supply chain participants, reported interviews with industry scientists reveal that markers should not be viewed as a replacement for conventional selection techniques. Indeed, selecting seedstock on the basis of a small number of available markers is not likely to produce the benefits that are currently being promised by life science companies. Consequently, this study recommends that the innovation be incorporated into existing seedstock selection practices. Much more analysis is needed to understand the full economic impact of gene markers for beef tenderness and for other beef quality attributes.
3

An economic analysis of gene marker assisted seedstock selection in beef cattle

Akhimienmhonan, Douglas 05 1900 (has links)
This study analyzes the economic impact of a recent gene marker innovation for seedstock selection in beef cattle. Gene markers are being developed for many beef cattle attributes; this study focused on the tenderness quality of beef using two categories: tender and tough. The study begins by describing conventional procedures for seedstock selection, the science which underlies selection by gene markers and other non-genetic procedures currently being used to improve beef tenderness. After describing the commercialization of the gene marker innovation, a stylized model of a beef supply chain is constructed. The supply chain consists of a representative consumer, a producer/processor group and a monopolist supplier of the patented technology. Welfare changes resulting from the adoption of the innovation were simulated using four sets of demand elasticity data from literatures. An important focus of this research is determining how the economic surplus from the innovation will be shared by consumers, producers and the gene marker monopolist. The consumer and gene marker monopolist benefit from the technology unless the marginal and fixed cost variables (not estimated in this study) of the monopolist, are excessively high. Producer surplus was simulated as positive with three of the four elasticity data sets. The share of surplus capture by producers is generally low relative to the gains captured by consumers and the gene marker monopolist. Comparative static analysis reveal that the benefit from the innovation varies across breeds, being higher for breeds in which the favorable form of the marker gene is more likely to be present. Despite the apparent benefits of the innovation for beef supply chain participants, reported interviews with industry scientists reveal that markers should not be viewed as a replacement for conventional selection techniques. Indeed, selecting seedstock on the basis of a small number of available markers is not likely to produce the benefits that are currently being promised by life science companies. Consequently, this study recommends that the innovation be incorporated into existing seedstock selection practices. Much more analysis is needed to understand the full economic impact of gene markers for beef tenderness and for other beef quality attributes. / Land and Food Systems, Faculty of / Graduate
4

Magnetic Resonance Molecular Imaging Using Iron Oxide Nanoparticles

Zurkiya, Omar 13 November 2006 (has links)
Magnetic resonance imaging (MRI) is regularly used to obtain anatomical images, greatly advancing biomedical research and clinical health care today, but its full potential in providing functional, physiological, and molecular information is only beginning to emerge. The goal of magnetic resonance molecular imaging is to utilize MRI to acquire information on the molecular level. This dissertation is focused on ways to increase the use of MRI for molecular imaging using superparamagnetic iron oxide (SPIO) nanoparticle induced MRI contrast. This work is divided into three main sections: <B>1)<I> Elucidation of the contribution of size and coating properties to magnetic nanoparticle induced proton relaxation.</I></B> To maximize contrast generated without increasing particle size, new methods to increase effects on relaxivity must be developed. Experimental data obtained on a new class of biocompatible particles are presented, along with simulated data. The effects of coating size, proton exchange, and altered diffusion are examined. Simulations are presented confirming the effect of particle coatings on clustering-induced relaxivity changes, and an experimental system demonstrating the clustering effect is presented. <B>2)<I> Development of a diffusion-dependent, off-resonance imaging protocol for magnetic nanoparticles.</I></B> This work demonstrates an alternative approach, off-resonance saturation (ORS), for generating contrast sensitive to SPIO nanoparticles. This method leads to a calculated contrast that increases with SPIO concentration. Experimental data and a mathematical model demonstrate and characterize this diffusion-dependent, off-resonance effect. Dependence on off-resonance frequency and power are also investigated. <B>3)<I> Development of a genetic MRI marker via in vivo magnetic nanoparticle synthesis.</I></B> This work seeks to provide a gene expression marker for MRI based on bacterial magnetosomes, tiny magnets produced by naturally occurring magnetotactic bacteria. Here, <I>magA</I> is expressed in a commonly used human cell line, 293FT, resulting in the production of magnetic, iron oxide nanoparticles by these cells. MRI shows these particles can be formed <I>in vivo</I> utilizing endogenous iron and can be used to visualize cells positive for <I>magA</I>. These results demonstrate <I>magA</I> alone is sufficient to produce magnetic nanoparticles and that it is an appropriate candidate for an MRI reporter gene.

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