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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

The Roles of Stop Codons and 3’ Flanking Base in Bacterial Translation Termination Efficiency

Wei, Yulong January 2016 (has links)
Understanding translation efficiency is crucial to pharmaceutical companies that have invested substantial time and effort in engineering bacteria to produce recombinant proteins. While translation initiation and elongation have been studied intensively, much remains obscure in the subprocess of translation termination. We aim to understand how stop codons and the first 3’ flanking (+4) base affect translation termination efficiency. In chapter two, we hypothesized that stop codon usage of UAG and UGA is dependent on the abundance of their respective decoders, RF1 and RF2. We predicted and observed that bacterial species with high relative proportions of RF1 uses UAG more, and vice versa for UGA. In addition, the usage of UGA, not UAG, is always avoided in highly expressed genes. Thus, we argued against the claim made by a recent study that UAG is a minor stop codon in bacteria. The claim is incorrect because UAG does not meet the two criteria of a minor codon: i) it is most avoided in highly expressed genes, and ii) it corresponds to the least abundant decoder. Interestingly, we found that the proportion of RF2 decreases rapidly towards zero in species with high AT contents; this explains why UGA is reassigned to a sense codon in bacterial lineages with high AT content. In chapter three, we examined the role of the first downstream (+4) base Uracil in bacterial translation termination. The +4U is associated with a decrease in stop codon read-through in bacteria and yeast. We hypothesized that i) +4U enhances the termination efficiency of stop signals, and ii) +4U may serve to prevent stop codon misreading by near cognate tRNAs (nc_tRNAs). We predicted that i) +4U is preferred in highly expressed genes (HEGs) than lowly expressed genes (LEGs), and ii) +4U usage increases with the frequency of stop codon nc_tRNAs. We found +4U consistently over-represented in HEGs in contrast to LEGs; however, +4U usage in HEGs decreases in GC-rich species where most stop codons are UGA and UAG. In addition, +4U usage increases significantly with UAA usage in the known highly expressed ribosomal protein genes. These results suggest that +4U is a strong stop signal enhancer for UAA, not UAG or UGA. Furthermore, in HEGs, +4U usage also increases significantly with the abundance of UAA nc_tRNAs, suggesting that +4U increases UAA termination efficiency presumably by reducing misreading of UAA by nc_tRNAs.
2

Studies on transcriptional termination

Wright, Joanna Jane January 1987 (has links)
No description available.
3

A STATUS REPORT OF THE JOINT ADVANCED MISSILE INSTRUMENTATION PROGRAM AN OFFICE OF THE SECRETARY OF DEFENSE CENTRAL TEST AND EVALUATION INVESTMENT PROGRAM INITIATIVE

Scofield, Don, Powell, Dave 10 1900 (has links)
International Telemetering Conference Proceedings / October 23-26, 2000 / Town & Country Hotel and Conference Center, San Diego, California / Joint Advanced Missile Instrumentation (JAMI), a 1997 new-start multi-year Central Test and Evaluation Investment Program (CTEIP), is developing advanced telemetry system components that can be used in an integrated instrumentation package for tri-service small missile test and training applications. JAMI will provide telemetry, Time-Space-Position Information (TSPI), flight termination and end-game vector scoring in a low cost, modular package that will allow world-wide test and training- eliminating, in most cases, the need for range-specific (or multi-system) facilities. JAMI will incorporate Global Positioning System (GPS)-based technology as the TSPI and vector scoring engine, and is completing the development of a solid state programmable safe and arm device for flight safety applications. The JAMI program has progressed into Phase 2 and full-scale development of advanced GPS technologies. This paper discusses the progress of the program during the past year and the efforts planned for fiscal year 2000. Testing of GPS receivers and problems encountered in programming GPS simulator for missile flight profiles are discussed.
4

A STATUS REPORT OF THE JOINT ADVANCED MISSILE INSTRUMENTATION PROGRAM AN OFFICE OF THE SECRETARY OF DEFENSE CENTRAL TEST AND EVALUATION INVESTMENT PROGRAM INITIATIVE

Scofield, Don, Powell, Dave 10 1900 (has links)
International Telemetering Conference Proceedings / October 25-28, 1999 / Riviera Hotel and Convention Center, Las Vegas, Nevada / Joint Advanced Missile Instrumentation (JAMI), a 1997 new-start multi-year Central Test and Evaluation Investment Program (CTEIP), is developing advanced telemetry system components that can be used in an integrated instrumentation package for tri-service small missile test and training applications. JAMI will provide telemetry, Time-Space-Position Information (TSPI), flight termination and end-game vector scoring in a low cost, modular package that will allow world-wide test and training- eliminating, in most cases, the need for range-specific (or multi-system) facilities. JAMI will incorporate Global Positioning System (GPS)-based technology as the TSPI and vector scoring engine, and address the feasibility of a solid state programmable safe and arm. This paper discusses the progress of the program during the Test Technology Development and Demonstration (TTD&D) phase and the efforts planned for fiscal year 1999. Preliminary testing of GPS receivers and conformal GPS antennas on missile platforms are discussed.
5

A STATUS REPORT OF THE JOINT ADVANCED MISSILE INSTRUMENTATION PROJECT HIGH DYNAMIC GPS- WE FINALLY GOT IT

Powell, Dave, Scofield, Don 10 1900 (has links)
International Telemetering Conference Proceedings / October 21, 2002 / Town & Country Hotel and Conference Center, San Diego, California / Joint Advanced Missile Instrumentation (JAMI), a Central Test and Evaluation Investment Program (CTEIP) initiative, is developing advanced telemetry system components that can be used in an integrated instrumentation package for tri-service small missile test and training applications. JAMI demonstrated significant improvement in the performance of low-cost Global Positioning System (GPS) based Time-Space-Position Information (TSPI) tracking hardware that can be used for world-wide test and training. Acquisition times of less than 3 seconds from a cold start and tracking dynamics to over 60 Gs were demonstrated. The design of a programmable Flight Termination Safe and Arm device has been completed. This paper discusses the progress of the program during the past year and the efforts planned for fiscal year 2002. High dynamic testing results of GPS and Inertial measurement Unit (IMU) devices and problems encountered are discussed.
6

A STATUS REPORT OF THE JOINT ADVANCED MISSILE INSTRUMENTATION PROGRAM AN OFFICE OF THE SECRETARY OF DEFENSE CENTRAL TEST AND EVALUATION INVESTMENT PROGRAM INITIATIVE

Powell, Dave, Scofield, Don 10 1900 (has links)
International Telemetering Conference Proceedings / October 22-25, 2001 / Riviera Hotel and Convention Center, Las Vegas, Nevada / Joint Advanced Missile Instrumentation (JAMI), a Central Test and Evaluation Investment Program (CTEIP) initiative, is developing advanced telemetry system components that can be used in an integrated instrumentation package for tri-service small missile test and training applications. JAMI has made significant progress in the development of Global Positioning System (GPS) based Time-Space- Position Information (TSPI) tracking hardware, flight termination equipment and end-game vector scoring technology in low cost, modular packages that will allow world-wide test and training. The JAMI program is in full-scale development of advanced GPS technologies to reduce the cold start Time- To-First-Fix (TTFF) to less than 3 seconds. This paper discusses the progress of the program during the past year and the efforts planned for fiscal year 2001. Testing results of GPS receivers to levels of over 50 Gs and problems encountered in programming GPS simulator for missile flight profiles are discussed.
7

Contraceptive study: an assessment of contraceptive use in patients requesting termination of pregnancy at Chris Hani Baragwanath hospital

Nyakoe, Robert Barasa 12 November 2009 (has links)
M.Med. (Obstetrics and Gynaecology), Faculty of Health Sciences, University of the Witwatersrand,2008 / The aim of this study was to assess the demographic characteristics and contraceptive practices of women requesting termination of pregnancy (TOP) at Chris Hani Baragwanath Hospital (CHBH). The study will provide insight into the reasons for contraceptive „failure‟ or non-use. Methods This is a cross sectional questionnaire survey. Subjects for the study were recruited from clients requesting TOP at the Gynaecology clinic (ward 54), CHBH. They included women between 13 to 49 years, who were referred from their local clinic or General practitioner with a positive pregnancy test or a pregnancy confirmed on sonar, and were less than 20 weeks pregnant. Consenting women completed a self-administered questionnaire which assessed their demographic details, current contraceptive use, past contraceptive experience, future contraceptive plans, knowledge of emergency contraceptive pill, and the current status of the relationship, initial intention with regard to the pregnancy, and the number of sexual partners they had in the last year. The data was analysed using the Epi Info 6 software programme. Results There were 780 requests for TOP during the study period. Two hundred and twenty nine women were approached to participate in the study and 203 questionnaires were analysed, i.e. an 89% analysable response rate. The mean age of the respondents was 25 years (range 13 - 42 years), the mean parity was 1.3 (range 0 to 9), 35% were still in school, 28% were unemployed and 70% were financially dependent on their parents, partners, or other relatives. A total of 56% of the respondents reported that they were using contraception when they conceived. Only 11% of the respondents knew of the emergency contraception pill. Eighty two percent of the respondents knew where to obtain contraceptives and only 7% had experienced actual difficulty in obtaining contraception. However, 46% thought they received „too little‟ information about contraception at their local clinic and 26% said that the contraceptive method they received was the healthcare provider‟s choice. Up to 47% of the respondents were either unsure of the contraceptive method they would use or would not use any contraception following the TOP. However, 43% would use a highly reliable contraceptive method (the oral contraceptive pill, injectable contraceptive, or sterilisation). Regarding the status of the relationship which resulted in the pregnancy, 44% were no longer in a permanent relationship (41% were and 11% never were). Twenty two percent of the respondents initially wanted the pregnancy. Conclusions Twenty two percent of the respondents initially wanted the pregnancy and would not have been helped by better provision of contraception. A large number of respondents reported contraceptive failure. Knowledge of emergency contraception was poor, and its use should be better promoted for cases of contraceptive failure. It is alarming that up to 47% of the clients could not use contraception in the future. Perhaps more time should be spent on contraceptive counselling and initiation of a method on site, with referral and follow-up at primary health clinics to improve uptake of contraception. Only 2.5% of the respondents were having a repeat TOP.
8

Software project Escalation and Termination study

Wu, Chun-i 05 August 2006 (has links)
This thesis is a case study of software project escalation and termination. According to domestic and international literature, software projects often faces escalation phenomenon. Therefore, this thesis studied three cases of information-system development from two different areas. The first two cases are about A and B natural gas companies¡¦geographic information system. Company A¡¦s geographic information system lasted for eight years and ended with termination. Company B¡¦s geographic information system lasted for ten years. During these years, company B had changed three different software solution providers, but the project is still pending until today. The third case is about Company C¡¦s ERP system development. The project was initiated in December of 2002 after signing the contract. It was targeted to finish in 2004. Until July, 2007, this project is not completely finished yet. From the above three cases, the causes of software project escalation and termination were investigated. What leads to the escalation of software project? Why is the software project terminated? What is the root cause? This research integrated the theoretical framework of project escalation and termination from literature. The framework addresses four key factors of escalation: (1) Project factor (2) Psychological factor (3) Social factor (4) Organizational factor (Staw and Ross, 1987); and also two key factors for termination: (1) Economic factor and management factor behind it (2) Technical factor and management factor behind it(Ewusi-Mensah and Przasnyski, 1991). Based on these factors, this study finds out affecting elements behind those factors,and then verifies and modifies the research framework. Finally, this thesis brings up conclusion and suggestions, hoping to provide managers with some advices when developing a new software project, in order to minimize the loss caused by escalation and termination.
9

Why Corporations Terminate Merging Processes: A Comparative Study for Four Cases

Yu, Kanhao 20 June 2002 (has links)
Abstract In order to increasing competitiveness, one of the most important trends is popularity of merges among Taiwanese firms. Many possible merges, however, were terminated before realization. This study finds that the completion rate is only about one fifth for all merging cases. This study compares four cases to understand reasons why corporations terminate merges before completing the merging processes. The four cases are ¡§Sampo and TECO¡¨, ¡§Twinhead and Uniwill¡¨, ¡§Yuen Foong Yu and Chung Hwa Pulp¡¨, and ¡§First Commerical Bank, Ta An Bank and Pan Asia Bank.¡¨ Collecting and analyzing data and reports from printed medias, this research finds that pursuing economy of scale and increasing market power are two most important motivations for corporate merges. There are seven important reasons for merge terminations: Intention of major shareholders, Share swap proportion, Management right, Opposition from employees, Regulations, Government intervention, and Politicians¡¦ influences.
10

The Subminiature Flight Safety System (SFSS) Development Progress

Lambeth, Stephen, Dehmelt, Chris 10 1900 (has links)
ITC/USA 2013 Conference Proceedings / The Forty-Ninth Annual International Telemetering Conference and Technical Exhibition / October 21-24, 2013 / Bally's Hotel & Convention Center, Las Vegas, NV / SFSS is a universal, small, and low cost, functionally redundant flight termination system (FTS) that incorporates encoding, processing and TSPI capabilities, provides critical health/safety/welfare monitoring and allows for highly efficient telemetering of weapon application and FTS data. The SFSS is intended as a solution to provide weapon system developers, test agencies, and range safety officers the ability to track, monitor, and if necessary, terminate all types of weapon systems. The SFSS components are intended to significantly reduce the recurring costs and improve the quality of test support by minimizing physical intrusion into weapon systems, and potentially eliminating the need for warhead removal. In addition, a common hardware suite assists in reducing the overall system cost of acquisition, a key element in today's world of stressed budgets. The SFSS is designed to interface with newly developed weapon systems, while providing the capability to be integrated into existing weapon systems with nominal modifications to the platform. The SFSS development is a multi-disciplinary effort, whose participating organizations include industry suppliers, range and system safety representatives, and technical offices from all branches of the armed services, as well as the weapons vendors to ensure that applicable technical and regulatory requirements are met. The original requirements for the project were defined within the SFSS System Performance Specification (SPS), which has undergone a number of updates as the design effort has progressed from concept to assembly and debug of the prototype components. This paper will provide an overview of the overall program status, key features of the SFSS including features added during development, critical design challenges, and additional activities planned to enhance the functionality of the system.

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