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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.
261

Inferring mode of locomotion through microscopic cortical bone analysis: a comparison of the third digits of Homo sapiens and Ursus americanus using Micro-CT

Harrison, Kimberly D. 18 December 2012 (has links)
Bone is a 3D dynamic and unique tissue that structurally adapts in response to mechanical stimuli. Comparative skeletal morphology is commonly utilized to infer ancient hominins' modes of locomotion; however, instances of remarkable gross similarity despite different modes of locomotion do occur. A common cited example is the similarity between the skeletal elements of bipedal human (Homo sapiens) hands/feet and quadrupedal black bear (Ursus americanus) front/hind paws. Through novel 3D Micro-CT and 2D histomorphology analysis, this thesis tests the hypothesis that a 3D microscopic analysis of biomechanically regulated cortical bone structures provides a more representative and accurate means to infer a species' mode of locomotion. Micro-CT data were collected at the mid-diaphysis of human (n=5) and bear (n=5) third metacarpal/metatarsal pairs and compared with independent and paired t-tests, Pearson correlation coefficients and Bland-Altman plots. Bone microarchitecture is quantifiable in 3D and accessible through non-destructive Micro-CT. Interspecies variation was present, however no significant cortical differences between elements of humans and bears was found. Histological inspection revealed further variation between and within species and element. A key limitation was sample size and further investigation of the relationship between mechanical loading and mode of locomotion is warranted.
262

Security market manipulations and the assurance of market integrity

Ji, Shan , Banking & Finance, Australian School of Business, UNSW January 2009 (has links)
This dissertation is motivated by two major factors. First, there have been no direct studies conducted for the relationship between market integrity and market efficiency and the driving forces behind the cross-sectional variations in market quality. Second, a better understanding the relationships among market integrity, market efficiency and other mechanism design factors for securities exchanges will facilitate securities exchanges achieve a satisfactory level of market quality. This dissertation consists of three chapters. In Chapter 1, a review of literature on market manipulation will be given. A series of common securities market manipulation strategies and corresponding market surveillance alerts will be explained and defined. In Chapter 2, we develop a testable hypothesis that market manipulation as proxied by the incidence of ramping alerts would raise transaction cost for completing larger trades. We find ramping alert incidence positively related to effective spreads in 8 of 10 turnover deciles from most liquid to thinnest-trading securities. The magnitude of the increase in effective spreads when ramping manipulation incidence doubles is economically significant, 30 to 40 basis points in many moderate liquidity deciles. This compares with an average effective spread of 72 basis points for index-listed securities in the most efficient electronic markets worldwide. In Chapter 3, In Chapter 3 of this thesis, we test the correlation between the levels of market integrity as proxied by the incidence of ramping alerts and a combination of proxies for factors from the following four potential drivers deciding the market quality across securities exchanges: ??? Securities Markets Trading Regulations ??? Securities Markets Technologies ??? Securities Market Infrastructure ??? Securities Market Participants The model we developed to test the correlation between the proxies for level of market integrity and seven proxies for the four potential drivers were estimated with Ordinary Least Square (OLS) and Two-stage Least Square (2SLS) error structures assumed, respectively to learn the most about the possible endogeneity of spreads and volatility. By performing Hausman-Wu specification tests, we concluded that simultaneity bias in the thickly-traded deciles is not material for the AI-Volatility and AI-Spread equation pairs. Subsequently, we used the PROBIT model to analyse the probability of adopting RTS across the 240 securities exchange deciles and the likelihood proves to be systematically related to four determinants in our sample. Finally we estimate the structural equations to investigate possible cross-equation correlation of the disturbances with either seemingly unrelated regression (SURL) estimation. Our findings are three-fold. Firstly, in the moderately-traded deciles, we find that the presence of a closing auction (CloseAucDum) reduces the incidence of ramping alerts. Trade-based manipulation proves more difficult when a manipulator???s counterparties can use closing auctions to unwind their intraday exposures. The RTS dummy variable is significantly positively related to alert incidence. In the absence of any panel data on the dynamic effects of adopting RTS, what we are observing in cross section is the perceived vulnerability of certain exchanges to manipulation and their consequent adoption of RTS plus the regulatory regimes required to have a salutary effect on market integrity. Second, in the moderately-traded deciles, we find that the closing auctions and more regulations in pursuit of market integrity lower quoted spreads. RTS and a regulation specifically prohibiting ramping indicate in cross-section the perceived likelihood of more ramping. Thirdly, in terms of the probability of the deployment of a real-time surveillance system, the estimations again differ by liquidity decile grouping. In the moderately-traded deciles, higher alert incidence, the presence of DMA, and higher FDI again increase the likelihood of adopting a real-time surveillance system. Our findings have a couple of policy implications for many securities exchanges in terms of market design and market surveillance. First, the exhibited relationship between alert incidence and effective spreads indicates trade-based manipulation has a significant impact on execution costs. Therefore, the prevention of securities market manipulation not only serves the indirect purpose of improving an exchange???s reputation for market integrity but also contributes directly to achieving a more efficient marketplace. Second, our results indicate that some market design changes can enhance the regulatory efforts to prevent securities market manipulations. For example, to prevent manipulators from marking the closing price, some exchanges could choose to adopt a closing auction or a random closing time, which would make manipulation more costly. Nevertheless, no securities exchange can be designed perfectly. Consequently, exchange and broker-level surveillance backed by effective regulatory enforcement is a necessary and pivotal complement to good design choices.
263

Microstructure and rheology of mixed ionic surfactants

Hollabaugh, Kate R. January 2009 (has links)
Thesis (M.Ch.E.)--University of Delaware, 2008. / Principal faculty advisors: Norman J. Wagner, Dept. of Chemical Engineering; and Eric W. Kaler, College of Engineering. Includes bibliographical references.
264

Computer simulations of realistic microstructures implications for simulation-based materials design/

Singh, Harpreet. January 2007 (has links)
Thesis (Ph. D.)--Materials Science and Engineering, Georgia Institute of Technology, 2008. / Committee Chair: Dr. Arun Gokhale; Committee Member: Dr. Hamid Garmestani; Committee Member: Dr. Karl Jacob; Committee Member: Dr. Meilin Liu; Committee Member: Dr. Steve Johnson.
265

A novel spectral framework for second-order homogenization theories /

Binci, Massimiliano. Kalidindi, Surya. January 2008 (has links)
Thesis (Ph.D.)--Drexel University, 2008. / Includes abstract and vita. Includes bibliographical references (leaves 68-73).
266

Crystallography, microstructure, and implications for the formation of the biomineralized system, nacre in red abalone /

Frech, Daniel W. January 1998 (has links)
Thesis (Ph. D.)--University of Washington, 1998. / Vita. Includes bibliographical references (leaves [239]-246).
267

Realistic micromechanical modeling and simulation of two-phase heterogeneous materials

Sreeranganathan, Arun January 2008 (has links)
Thesis (Ph.D.)--Materials Science and Engineering, Georgia Institute of Technology, 2008. / Committee Chair: Gokhale, Arun; Committee Member: Gall, Kenneth; Committee Member: Garmestani, Hamid; Committee Member: Kurtis, Kimberly; Committee Member: Thadhani, Naresh
268

Physical simulation of friction stir processed TI-5AI-1Sn-1Zr-1V-0.8Mo

Rubal, Melissa Joanne, January 2009 (has links)
Thesis (M.S.)--Ohio State University, 2009. / Title from first page of PDF file. Includes vita. Includes bibliographical references (p. 108-109).
269

Elasticity in microstructure sensitive design through the use of Hill bounds /

Henrie, Benjamin L., January 2002 (has links) (PDF)
Thesis (M.S.)--Brigham Young University. Dept. of Mechanical Engineering, 2002. / Includes bibliographical references (p. 41-43).
270

Microstructure profiles

Christiansen, Carl. January 1980 (has links)
Thesis (M.S.)--Naval Postgraduate School, 1980. / Includes bibliographical references (leaves 56-57).

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