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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

Molecular cloning and characterization of three enzymes involved in Taxol/Taxoid biosynthesis Taxoid 2[alpha]-hydroxylase, Taxoid 7[beta]-hydroxylase, and Taxoid 5[alpha]-O-Acetyl transferase /

Chau, Mydoanh, January 2004 (has links) (PDF)
Thesis (Ph. D. in Molecular Plant Sciences)--Washington State University. / Includes bibliographical references.
2

A study of the genus taxus /

Keen, Ray A. January 1956 (has links)
No description available.
3

Synthesis amongst taxanes

Harrison, A. G. January 1986 (has links)
No description available.
4

Reproductive biology of Pacific yew (Taxus brevifolia)

Anderson, Erika Dee 17 May 2018 (has links)
Taxus brevifolia Nutt., commonly known as Pacific or Western yew, is a conifer native to the Pacific Northwest of North America. Contrary to other Taxus species, T. brevifolia staminate strobili are usually located on two-year old foliage though they may occur on foliage from one to five years old. This delayed staminate strobilus development may be an adaptation to the low light environment where T. brevifolia grows. Microsporogenesis was found to occur in the fall preceding pollination. Isobilateral tetrads were visible as early as mid-October. Over-wintering staminate strobili usually contained separate microspores. In 1996 through 1999, pollination occurred in March and April in two natural forest sites on southern Vancouver Island, British Columbia. Low amounts of airborne pollen and a prolonged pollination period indicated low pollination success within T. brevifolia. Female receptivity was measured by the presence of a pollination drop and protandry up to 18 days was observed. In vitro pollen germination was moderate to good, ranging from 65% to 88%. DAPI fluorescence staining showed successful male gametophyte development in vitro. The phenology of megasporogenesis and free nuclear mitosis within the megagametophyte was variable and this development occurred anytime between early February until the end of June. One megaspore mother cell developed from the sporogenous tissue and underwent meiosis forming a linear tetrad of megaspores. Though up to three of the megaspores may be functional, the chalazal megaspore developed faster than the others and became the dominant megaspore. Cellularization of the megagametophyte began in mid-April and continues until early June. The presence of an ephemeral ventral canal nucleus was confirmed. Fertilization was observed in June in 1996. The mature egg cell cytoplasm and sperm structure was used to infer paternal inheritance of plastids and biparental inheritance of mitochondria. To examine this further, DNA was extracted from hybrid embryos of T. brevifolia and T. x media Rehd. Paternal contribution of mitochondria was confirmed using the probe rpS 14-cob. The T. x media parents produced two bands of 526 and 970 by in length, whereas the T. brevifolia parents produced only one band (526 bp). The chloroplast probes were not effective at amplifying Taxus DNA although appropriate sized bands were produced in Pinus contorta. Proembryos occurred from mid-May to mid-June. Sixteen nuclei were present before cellularization. Early embryos were present from mid-May to mid-August. Simple polyembryony was observed up to the massive embryo stage and differential growth of the embryonal cells was interpreted as incomplete cleavage polyembryony. Mid-embryos were present from mid-June to late August and had a distinct protoderm and focal zone. Late embryos were visible from mid-July onwards. Starch began accumulating at the early embryo stage, whereas, proteins and lipids accumulated in the late embryo stage. The presence of a red aril corresponded to increased amounts of lipid in the megagametophyte cells. Individual seeds matured from July until November. The seed efficiency ranged from 0% to 16% and averaged 5%. Pre-zygotic loss was the most common fate of ovules, followed by post-zygotic loss. Possible causes of this poor seed efficiency are poor pollination success, insect damage or light limitation. / Graduate
5

The Study of Authoritarian Regime in Singapore.

Yang, Zhen-Ting 11 September 2012 (has links)
In 1965, Singapore became independent. While this country¡¦s history is not a long one, nor is its surface area expansive, its economic prowess has astounded all. It is truly a city state which deserves closer examination. The long rule of the People¡¦s Action Party includes the terms of Prime Ministers Lee Kuan Yew, Goh Chok Tong, and Lee Hsien Loong. While this period has been marked with outstanding economic accomplishments, Singapore¡¦s political development has been primarily under an authoritarian leadership model. This study divides these three administrations into the Lee Kuan Yew period and post Lee Kuan Yew period and analyzes methods of rule the People¡¦s Action Party takes with respect to politics, economic issues, and social issues in creating its authoritarian regime today. In the political realm, the People¡¦s Action Party limited opposition from gaining political control through intended and actual operations. In the economic realm, they created large nationally owned companies covering an enormous scope and, through the cooperation of labor, capital, and governance, kept their hand on the levers of the economy. With respect to society, the People¡¦s Action Party controlled media and news publications in order to slow the development of civil society. Thus, they have achieved stability in their authoritarian rule. The same time, the theory through Western authoritarian, it is attributed to the authoritarian rule of the common features in order to distinguish between Singapore today is what type of authoritarian regime. Found that Singapore, although from time to time that congressional elections are held regularly, but still did not have a fair and free election system, therefore be classified as a mixed constitution "competitive authoritarian" regimes. Contemporaneously,western theories are utilized to draw conclusions concerning the common characteristics of authoritarianism and distinguish what type of authoritarian regime Singapore is today. This study finds though Singapore holds regular parliamentary elections from time to time, it has never held fair or free elections and must therefore be classified as a hybrid ¡§competitive authoritarian¡¨ form of government.
6

Ecological understandings of Indigenous landscape management shape the study of Pacific yew (Taxus brevifolia)

Reynolds, Geneviève 02 September 2022 (has links)
Indigenous landscape management has transformed ecosystems for millennia, with long-lasting impacts on the productivity and abundance of plant species. While western science based ecological research is beginning to investigate these impacts, less abundant species of cultural importance remain understudied. Pacific yew (Taxus brevifolia Nutt.), an uncommon understory conifer found in old-growth forests of the Northwest Coast of North America, has not received sustained ecological interest despite its importance to Indigenous Peoples throughout its range. In the first chapter, I synthesize the current ethnobotanical and ecological literature discussing Pacific yew to identify knowledge gaps and dominant paradigms that have shaped the study of the species. I find that many mechanisms behind Pacific yew’s habitat selection and ecosystem functions are unknown to western science and that the impacts of Indigenous landscape management are largely unacknowledged within the western scientific literature. In the following chapter, in partnership with the Heiltsuk First Nation, I examine the growth and abundance of Pacific yew on sites that were inhabited intensively by First Nations on the Central Coast of British Columbia for over 10,000 years. I find that habitation histories are not a strong driver of patterns of tree size and that Pacific yew abundance is largely driven by site aspect. These findings shed light on the habitat preferences of Pacific yew, which have rarely been studied in this region. They also illustrate variation in the response of culturally important species to landscape modification and highlight the need for nuanced understanding of the diversity of plant management strategies employed by Indigenous Peoples. This work is part of a broader attempt to incorporate cultural histories and questions into ecological study and to recognize the continuing ecological influences of Indigenous Peoples, who have stewarded their homelands for millennia. / Graduate
7

Susceptibility of Pacific yew (Taxus brevifolia Nutt.) to Phytophthora lateralis

Murray, Marion S. 10 April 1995 (has links)
In 1991 Pacific yew (Taxus brevifolia Nutt.) was reported as a new host for Phytophthora lateralis Tucker and Milbrath which is an aggressive root rot pathogen thought previously to be specific to Port-Orford-cedar. This study was designed to compare the pathogenicity of P. lateralis on the two hosts, and to characterize sites where Pacific yew mortality occurs. The specific objectives were: 1) compare root colonization and mortality of Pacific yew and Port-Orford-cedar seedlings and rooted cuttings; 2) compare lesion length on inoculated Pacific yew and Port-Orford-cedar branches and stems; 3) compare zoospore attraction to freshly cut Pacific yew and Port-Orford-cedar rootlets; 4) compare amount of mortality of Pacific yew and Port-Orford-cedar in infested drainages and determine extent of yew mortality; and 5) characterize sites where P. lateralis causes Pacific yew mortality. Root colonization of P. lateralis was significantly greater in cedar than in yew. Seedling mortality averaged 58% for cedar and 4% for yew. Lesion length on the cedar seedling stems was twice the lesion length on yew stems, and cedar branches had lesions four times longer than yew branches. Abundant zoospore aggregation occurred on cedar rootlets along the zone of elongation and the region of maturation. In comparison, far fewer zoospores encysted along the yew rootlets, and were concentrated on the root hairs. The stream survey of three infested drainages in southwest Oregon and northwest California revealed a total of 1199 dead Port-Orford-cedar (46% mortality), and 86 dead Pacific yew (10% mortality). At sites where P. lateralis-induced mortality occurred, the interaction of slope and distance from the stream was negatively correlated with tree death. Based on results of this study, we conclude that Pacific yew is less susceptible to P. lateralis than Port-Orford-cedar, but that mortality of Pacific yew in the field is greater than previously reported. In addition, Pacific yew mortality was observed most often on level to nearly-level sites close to the stream's edge where root exposure to P. lateralis-infested water was frequent in scope and duration. / Graduation date: 1995
8

Do Females Differ From Males Of European Yew (Taxus Baccata L.) In Dedrochronological Analysis?

Cedro, Anna, Iszkulo, Grzegorz 01 1900 (has links)
Female and male plants often differ in reproductive effort and habitat requirements. The aim of this study was to analyze these differences between the sexes and the effect of climate on tree-ring width in European yew (Taxus baccata). The study was conducted in five yew populations in western Poland. Wood samples were taken from 196 trees (98 females and 98 males) and subjected to the standard procedure of dendrochronological dating. Mean tree-ring width was significantly higher in males since about the beginning of sexual maturity. No such relationship was observed in the youngest population, which is the most distant from the current geographic limit for this species. In most of the analyzed populations, width of tree rings in female individuals, in contrast to males, was negatively correlated with high temperatures in August and September in the year prior to the formation of the tree ring, and correlated positively with precipitation in June and July in the current year. The differentiation of tree-ring width between males and females likely began when the yew trees reached sexual maturity, probably because of the assumed greater reproductive effort of females in comparison with males. The lack of difference in the youngest population may result from a short time since the beginning of sexual maturity or from a milder climate in that region. Different reactions of the two sexes to climate indicate that this may affect the range and viability of populations at the limits of the range.
9

Leadership Behavior Theory and Practice-Research of the Case Leadership Behavior Lee Kuan Yew in Singapore

Chang, Yung-Chang 02 January 2003 (has links)
Leadership behavior theory and practice¡ÐResearch of the case Leadership behavior Lee Kuan Yew in Singapore. Abstract Leadship capability is not only inherent, it must be created by leaning and training also. And the leadership should have characteristics, which depends on the surroundings. Basically leadership has three types, which are dictatorship, laissez-faire, democratic. A leader must be responsible for his subordinates, team and superintendents. Excellent morality and advanced knowledge are the requisites for a good leader. The goal of leadship behavior is to prevent the troubles about people and things, then furthermore start his career and make contributions to the peoples. Finally he is to earn the sympathy of the crowd and erect his enterprise. The leadership behavior is show of creative intelligence and skill during solving the problems of ¡§people¡¨ and ¡§matters¡¨. It condenses the moral, wisdom, experience, ability and social relationship of the leader and displays the outstanding enchantment and boldness. It depends on the brain to operate powerfully, make use of main theme, depend on concentrate one¡¦s attention. Leadership is an very important intellect, it needs both theory and applications. In the daily life and the process of dealing the human affairs, people experience the tastes of leading and being lead. However, in the history, it is not difficult to find that some leaders are very prominent and bring happiness to human being, while some are very bad, caused masses in anguish and distressed. The public would justify that he is a success or a failure. Singapore is well known as a ¡§garden city¡¨ as well as a lawful nation. The government is famous for it ¡§being small with strength and being capable with uprightness¡¨. The leader, Lee Kuan Yew is the greatest contributor. Although he is criticized as tyrant, arbitrary, authoritative, he had been always persisting in his idea, not excited by the Western merits, advocacy ¡§Asian Values¡¨ and ¡§Confucianism¡¨ executing his ¡§Eastern authoritarian leadership style¡¨. Under his conduct, Singapore changes from head to feet and is praised as a miracle of ¡§politics and economics¡¨ in the world. Surely, that a country is strong or feeble depends on many aspects but the leader with sapience and characteristics of a statesman plays the main role. As is said, ¡§soldiers moves around their general¡¨, a leader constantly creates environments, then the people become accustomed in the district and go with his action as the leader go along with the timely opportunity, topographical advantage and social harmony. Lee Kuan Yew and his elitist cadres established the stable foundation for burgeoning by means of subjugating, candid, sagacious and practical leading style. We can examine the political leadership manner of Lee Kuan Yew carefully¡HHow he exert the leadership ability to confront challenge, break through predicament, overcome troubles and finally win the victory, shows boldness, intelligent resolution, braveness of a statesman everywhere. Anyway we can learn much more from Lee Kuan Yew.
10

Development Policies as Social Contract : Political leadership in Indonesia, Singapore and Malaysia

Gustafsson, Karl-Martin January 2007 (has links)
<p>This thesis will show how authoritarian governments rest legitimacy on their ability to create socio-economic development. It will point to some methods used to consolidate power by authoritarian leaders in Indonesia, Singapore and Malaysia. An authoritarian regime that successfully creates development is strengthened and does not call for democratic change in the short run. It is suggested that the widely endorsed Lipset hypothesis, that development will eventually bring democratic transition, is true only when further socio-economic development requires that the economy transfers from being based on industrial manufacturing to knowledge and creativity – not on lower levels of development. Malaysia and Singapore have reached – or try to reach – this level of development today, but restrictions on their civil societies have still not been lifted.</p><p>This thesis describes modern political history in Indonesia, Singapore and Malaysia in a Machiavellian tradition. The historical perspective will give a more or less plausible idea of how authoritarian regimes consolidated au-thority and what role development policies played in the leaders’ claims for authority. The conclusion will give a suggestion on how the political future in these three countries might evolve. It will point to the importance of an active and free civil society as a means to develop the nations further, rather than oppression.</p><p>This thesis will try to point to the dos and don’ts for authoritarian regimes. The ideas of Plato, Machiavelli and Hobbes provide the structures and methods that authoritarian regimes apply. It will be shown that a regime will disintegrate when it fails to comply with Plato’s and Machiavelli’s ideas. Al-though ancient, Plato and Machiavelli provide methods and structures that seem to carry relevance to the modern history of Southeast Asia.</p><p>I will point to how authoritarian rule can be maintained in the long run. What is required from the political leadership, what are their strategies and methods? What makes people to tolerate or topple authoritarian regimes? Why do some authoritarian regimes successfully create development while others do not? These are some of the questions this thesis will try to an-swer.</p>

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