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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.
461

Chiral Pyridine-Containing Ligands for Asymmetric Catalysis. Synthesis and Applications

Rahm, Fredrik January 2003 (has links)
This thesis deals with the design and syntheses of chiral,enantiopure pyridinecontaining ligands and their applicationsin asymmetric catalyis. Chiral pyridyl pyrrolidine ligands and pyridyl oxazolineligands were synthesized and employed in thepalladium-catalysed allylic alkylation of 1,3-diphenyl-2-propenyl acetate with dimethyl malonate. Theinfluence of the steric properties of the ligands wereinvestigated. Ditopic ligands, containing crown ether units as structuralelements, were synthesized and some of the ligands were used asligands in the palladiumcatalysed allylic alkylation of1,3-diphenyl-2-propenyl acetate with dimethyl malonate. A smallrate enhancement was observed, compared with analogous ligandslacking the crown ether unit, when these ditopic ligands wereused in dilute systems. A modular approach was used to synthesize chiralenantiomerically pure pyridyl alcohols and C2-symmetric2,2’-bipyridines, with the chirality originating from thechiral pool. Electronic and steric properties of the compoundswere varied and they were used as ligands in theenantioselective addition of diethylzinc to benzaldehyde. Thesense of asymmetric induction was found to be determined by theabsolute configuration of the carbinol carbon atom. Theelectronic properties of the ligands had a minor influence onthe levels of enantioselectivity induced by the ligands. Chiral pyridyl phosphinite ligands and pyridyl phosphiteligands were synthesized from the pyridyl alcohols andevaluated as ligands in palladiumcatalysed allylic alkylations.With the phosphinite ligands, the sense of chiral induction wasfound to be determined by the absolute configuration of theformer carbinol carbon atom. A kinetic resolution of theracemic starting material was observed with one of thephosphite ligands. Moderate enantioselectivities wereachieved. <b>Kewords:</b>asymmetric catalysis, chiral ligand, chiralpool, oxazoline, crownether, ditopic receptor, bipyridine,pyridyl alcohol, modular approach, P,Nligand, diethylzinc,allylic alkylation.
462

Humans and Seagrasses in East Africa : A social-ecological systems approach

de la Torre-Castro, Maricela January 2006 (has links)
The present study is one of the first attempts to analyze the societal importance of seagrasses (marine flowering plants) from a Natural Resource Management perspective, using a social-ecological systems (SES) approach. The interdisciplinary study takes place in East Africa (Western Indian Ocean, WIO) and includes in-depth studies in Chwaka Bay, Zanzibar, Tanzania. Natural and social sciences methods were used. The results are presented in six articles, showing that seagrass ecosystems are rich in seagrass species (13) and form an important part of the SES within the tropical seascape of the WIO. Seagrasses provide livelihoods opportunities and basic animal protein, in from of seagrass associated fish e.g. Siganidae and Scaridae. Research, management and education initiatives are, however, nearly non-existent. In Chwaka Bay, the goods and ecosystem services associated with the meadows and also appreciated by locals were fishing and collection grounds as well as substrate for seaweed cultivation. Seagrasses are used as medicines and fertilizers and associated with different beliefs and values. Dema (basket trap) fishery showed clear links to seagrass beds and provided the highest gross income per capita of all economic activities. All showing that the meadows provide social-ecological resilience. Drag-net fishery seems to damage the meadows. Two ecological studies show that artisanal seaweed farming of red algae, mainly done by women and pictured as sustainable in the WIO, has a thinning effect on seagrass beds, reduces associated macrofauna, affects sediments, changes fish catch composition and reduces diversity. Furthermore, it has a negative effect on i.a. women’s health. The two last papers are institutional analyses of the human-seagrass relationship. A broad approach was used to analyze regulative, normative and cultural-cognitive institutions. Cooperation and conflict take place between different institutions, interacting with their slow or fast moving characteristics, and are thus fundamental in directing the system into sustainable/unsustainable paths. Ecological knowledge was heterogeneous and situated. Due to the abundance of resources and high internal control, the SES seems to be entangled in a rigidity trap with the risk of falling into a poverty trap. Regulations were found insufficient to understand SES dynamics. “Well” designed organizational structures for management were found insufficient for “good” institutional performance. The dynamics between individuals embedded in different social and cultural structures showed to be crucial. Bwana Dikos, monitoring officials, placed in villages or landing sites in Zanzibar experienced four dilemmas – kinship, loyalty, poverty and control – which decrease efficiency and affect resilience. Mismatches between institutions themselves, and between institutions and cognitive capacities were identified. Some important practical implications are the need to include seagrass meadows in management and educational plans, addressing a seascape perspective, livelihood diversification, subsistence value, impacts, social-ecological resilience, and a broad institutional approach.
463

Regional and local variation in plant species richness

Dupré, Cecilia January 2001 (has links)
In this thesis, I examine the variation in plant species richness along gradients of productivity and disturbance in grasslands and forest habitats in southern Sweden, and I compare the documented patterns with theoretical predictions. Moreover, I evaluate the relative importance of habitat quality and habitat configuration for the occurrence of field layer species in deciduous forests. Finally, I present a new method for the determination of the regional species pool. To examine regional and local variation in plant species richness, I gathered data on species composition in plots of different size (0.001 - 1000 m2) in three vegetation types (deciduous forests, dry grasslands and coastal meadows) in four regions of southern Sweden (Öland, Gotland, Småland and Uppland). As predicted by the species pool hypothesis, differences in small-scale species richness of deciduous forests and dry grasslands were correlated with differences in the size of the regional species pool. Moreover, among plots large-scale diversity was predictive of small-scale diversity. Species diversity showed a hump-shaped relationship with productivity in forests, and was related to environmental heterogeneity and the size of the 'habitat-specific' species pool. In the two types of grassland examined, grazed sites were richer in species than abandoned sites. Moreover, both species composition and the representation of plants with different life-history characteristics differed between grazed and abandoned sites. As predicted by the intermediate disturbance hypothesis, species richness was highest at intermediate levels of grazing in coastal meadows. However, all the above patterns were scale-dependent, and not observed at all plot sizes. The occurrence of field layer species in deciduous forests was more strongly related to habitat quality (mainly soil factors) than to habitat configuration (forest area and isolation). Across species, low seed production, clonal reproduction and habitat specificity were negatively associated with isolation.
464

Re-Inventing the Past, Defining the Future: Historical Representations and Regional Development in the Russian Northwest

Sorokina, Alfia 25 May 2010 (has links)
This work explores the connections between the constructed representations of places based on local histories, the processes of tradition reinvention and the strategies of regional development in two Russian regions. This analysis also outlines the context created by the external to the regions influences and the associated with them local conditions.
465

中華郵政人才發展機制探討 / A Case Study on the People Development Systems of Chunghwa Post

劉錫標 Unknown Date (has links)
本研究是以人力資源發展理論與趨勢為基礎,並參考業界的作法,探討中華郵政如何建構人才發展體系,提升人力素質,強化企業競爭力。 人才發展體系可歸納出功能及執行二個構面,其中功能構面包含訓練體系、訓練藍圖、職涯發展路徑及人才庫;執行構面包含學程學分制、學習管理、個人發展計畫及訓用合一等。而推展人才發展體系關鍵成功因素有三,一是擁有成熟訓練經驗的統籌單位;二是單位合作分工,與實務緊密結合;三是透過資訊科技整合運用。 在建置的步驟上依序為分析組織人力與人才需求;分析訓練與發展需求;規劃訓練體系架構及訓練學習藍圖;針對個人及組織發展建構員工職涯發展資訊與路徑及人才庫機制;以資訊系統將各項作業做系統性整合;透過個人發展計畫及學程學分制度強化人才培育效能。 建置人才發展體系所產生的效益如下: 1.建置訓練體系及訓練藍圖:從公司角度,依員工職務性質規劃學習內容,提升訓練成效;從員工角度,主動規劃個人年度學習,獲得期望的工作技能與成長;從主管角度,緊密結合育才與用才,提升部門績效;從訓練規劃角度,有效簡化作業與縮短流程。 2.建置職涯發展資訊與路徑:對公司,能支援組織的發展與活化人力資源;對員工,能有清楚的發展方向,提昇工作的動力與滿足感;對主管,能有效發揮部屬的潛力並增加人力配置的彈性。 3.建置人才庫:對公司,有計畫的培育關鍵人才,有效支援組織中長期之策略性發展;對有高潛力的員工,能感受到有很好的職涯發展,更願竭盡所能為公司打拼。 / The research is based on theory and trends about development of human resources. Referring to actual practice in the field, the research will discuss how to construct people development systems, to enhance quality of human resources and to strengthen enterprise competitiveness in Chunghwa Post. People development systems can be concluded into functional and executive dimensions. The former includes training system, training map, career development path and talent pool, and the later contains program and credit system, learning management, individual development program & combination of training and employing. To promote people development systems successfully, there are several critical factors. Except owning an overall planning department with mature training experience, every department should work together and combine the work closely with practical experience following by integration of information technology. Building steps for the system following with analysis of manpower and talent needs, analysis of training development needs, plan for training structure and learning map, construction of staff’s career development path and talent pool mechanism in connection with personal and organizational development, integration of every operation by information system, and reinforcement personnel training performance through personal development plans and program & credit system. Generated benefits from the above steps are as below: A.Buildup of training structure and learning map: from the company’s angle, it enhances training effectiveness if the learning program designed by staff’s duties; from the staff’s point of view, they will obtain the desired working skills and growth through its annual personal learning programs; from the supervisor’s point of view, it closely connects talent use and cultivation, enhancing sector performance; considering the training plan, it simplifies operations and shorten process. B. Buildup of career development information and path: for the company, it supports organizational development and activated human resources; for the staff, it provides clear directions, as well as promoting work motivation and satisfaction; for the supervised, it effectively develops the staff’s potential and increase flexibility of placement. C. Buildup of talent pool: for the company, it cultivates key personnel, efficiently supporting medium-and-long-term strategic development, for the high-potential staff, it feels good career development, pushing them willing to work as hard as they can to the company.
466

Modeling of LNG Pool Spreading and Vaporization

Basha, Omar 1988- 14 March 2013 (has links)
In this work, a source term model for estimating the rate of spreading and vaporization of LNG on land and sea is introduced. The model takes into account the composition changes of the boiling mixture, the varying thermodynamic properties due to preferential boiling within the mixture and the effect of boiling on conductive heat transfer. The heat, mass and momentum balance equations are derived for continuous and instantaneous spills and mixture thermodynamic effects are incorporated. A parameter sensitivity analysis was conducted to determine the effect of boiling heat transfer regimes, friction, thermal contact/roughness correction parameter and VLE/mixture thermodynamics on the pool spreading behavior. The aim was to provide a better understanding of these governing phenomena and their relative importance throughout the pool lifetime. The spread model was validated against available experimental data for pool spreading on concrete and sea. The model is solved using Matlab for two continuous and instantaneous spill scenarios and is validated against experimental data on cryogenic pool spreading found in literature.
467

Re-Inventing the Past, Defining the Future: Historical Representations and Regional Development in the Russian Northwest

Sorokina, Alfia 25 May 2010 (has links)
This work explores the connections between the constructed representations of places based on local histories, the processes of tradition reinvention and the strategies of regional development in two Russian regions. This analysis also outlines the context created by the external to the regions influences and the associated with them local conditions.
468

Chiral Pyridine-Containing Ligands for Asymmetric Catalysis. Synthesis and Applications

Rahm, Fredrik January 2003 (has links)
<p>This thesis deals with the design and syntheses of chiral,enantiopure pyridinecontaining ligands and their applicationsin asymmetric catalyis.</p><p>Chiral pyridyl pyrrolidine ligands and pyridyl oxazolineligands were synthesized and employed in thepalladium-catalysed allylic alkylation of 1,3-diphenyl-2-propenyl acetate with dimethyl malonate. Theinfluence of the steric properties of the ligands wereinvestigated.</p><p>Ditopic ligands, containing crown ether units as structuralelements, were synthesized and some of the ligands were used asligands in the palladiumcatalysed allylic alkylation of1,3-diphenyl-2-propenyl acetate with dimethyl malonate. A smallrate enhancement was observed, compared with analogous ligandslacking the crown ether unit, when these ditopic ligands wereused in dilute systems.</p><p>A modular approach was used to synthesize chiralenantiomerically pure pyridyl alcohols and C2-symmetric2,2’-bipyridines, with the chirality originating from thechiral pool. Electronic and steric properties of the compoundswere varied and they were used as ligands in theenantioselective addition of diethylzinc to benzaldehyde. Thesense of asymmetric induction was found to be determined by theabsolute configuration of the carbinol carbon atom. Theelectronic properties of the ligands had a minor influence onthe levels of enantioselectivity induced by the ligands.</p><p>Chiral pyridyl phosphinite ligands and pyridyl phosphiteligands were synthesized from the pyridyl alcohols andevaluated as ligands in palladiumcatalysed allylic alkylations.With the phosphinite ligands, the sense of chiral induction wasfound to be determined by the absolute configuration of theformer carbinol carbon atom. A kinetic resolution of theracemic starting material was observed with one of thephosphite ligands. Moderate enantioselectivities wereachieved.</p><p><b>Kewords:</b>asymmetric catalysis, chiral ligand, chiralpool, oxazoline, crownether, ditopic receptor, bipyridine,pyridyl alcohol, modular approach, P,Nligand, diethylzinc,allylic alkylation.</p>
469

台灣專利聯盟(Patent Pool)的可行性探討─以國際產業標準的營運模式為例 / The feasibility analysis of Patent Pool in Taiwan─The Business Model of International Standard

徐弘光, Hsu, Henry Unknown Date (has links)
近年來,台灣高科技廠商開始投注大量的心血在於專利申請上,由公告的美國專利數目,台灣專利權人2005年在美獲取專利數已位居美國以外國家的第三位,在這樣的數據下,應該值得驕傲,然若從訴訟案例來看,台灣廠商卻仍明顯處於被指控專利侵權的窘境,在光電產業、光儲存產業、半導體產業、IC設計業等,有相當多的案例說明台灣廠商雖然在專利的數量上已達一定的成效,但營運上卻因為專利議題而障礙重重。 許多專利聯盟案例的成功,如MPEG LA與DVD 6C都說明了以專利為基礎所產生標準後能帶來的龐大商業利益。使得標準之爭,成為國際級大集團的必爭之地。反觀台灣或是中國,近年來都有許多與標準相關的聯盟產生,但都未能為主流產品所遵循、參與。 本文藉由MPEG-2 的案例,對於技術、專利、產品、產業的相互關係作一實證的探討,並以國際級跨國公司的智權管理來分析其營運模鏈式。發現推動標準的領導廠商,在標準制訂過程中,積極地參與標準組織、轉化研發成果為專利;在專利的佈局上,也善用專利申請的技巧在各國廣佈專利;積極推廣標準成為主流後,再組成專利聯盟、訂立授權機制。 國內廠商,若要制訂標準、組成專利聯盟,應建立許多研發的配套機制,例如研發過程中,標準、產品與專利的結、產業上中下游價值鏈的安排、研發聯盟的組成等。 / Hi-tech companies in Taiwan have begun to focus their resources on patent prosecution and the added-value thereafter in recent years. According to the statistics of USPTO, Taiwan ranks 3th on the total patent granted to a foreign origin. This is clearly an achievement to be proud of. However, Taiwan companies are still subject to many infringement challenges, be they in the field of optoelectronics, optical storage, semi-conductor or IC design. Clearly the growing patent ownership has not quite resolved the intellectual property issues these companies must overcome. The success of patent pools can bring profit to companies. In cases of MPEG LA and DVD 6C, they makes standard war a critical issue to international companies. On the contrary in Taiwan and China, many alliances aiming to promote standard fail to become standard finally. The case of MPEG-2 is analyzed in the aspects of technology, patent, product, industry and also their interactions. In addition, the IP management of the business model is also discussed. We found the leading company of industrial standard are aggressively participating the standard organization and applying patents. In patent application, there were skillfully in filing patents in different countries. After the technology become dominant standards, they start to form patent pool and build the license mechanism. Domestic companies should establish the infrastructure of R&D before setting standard and forming patent pool. For example, the connections of standard, product development, patent application, industrial value chain and R&D alliance should be planed and established during R&D process.
470

Fishermen, Politics, and Participation: An Ethnographic Examination of Commercial Fisheries Management in St. Croix, U.S. Virgin Islands

Grace-Mccaskey, Cynthia 01 January 2012 (has links)
Currently, there is widespread debate regarding the overall status of the world's fisheries, with some researchers projecting their total collapse in only a few decades, and others concluding the situation is not quite as bleak. Additional debates include what strategies should be used to manage fisheries at various scales, and further research is needed to determine which strategies are most appropriate for use in particular situations and locales, as context is critical. Recently, prominent common pool resources scholars have expressed the need for ethnographic approaches to studying resource management institutions in order to move beyond the current focus of simply identifying the factors and conditions that lead to the self-organization of resource users and long-term sustainability of management institutions. These authors describe the need for examining the larger context in which management institutions exist and taking various historical, political, and sociocultural factors into account when examining common pool resources. This dissertation is a response to that request. This research is the result of over 20 months of ethnographic research in St. Croix, United States Virgin Islands (USVI). Drawing on research in political ecology and building on anthropological critiques of common pool resource institutions, I describe the historical, social, and political factors that influence how fisheries management occurs at the federal and territorial levels, and how commercial fishers, managers, and other stakeholders experience and participate in multi-scale management processes. Ethnographic data suggest that there are a variety of historical, social, and political factors that influence how commercial fishers, managers, and other stakeholders perceive the federal fisheries management process, the extent of their participation in that process, as well as interactions within and between stakeholder groups. Additionally, the mismatch that exists between the centralized management structure of the US federal system and the small-scale, multi-method nature of St. Croix's fishery creates a complex management environment in which few stakeholders participate.

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