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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.
31

The Effects of Color Concentrates on the Rheology of Tint Bases

Herrick, Doug James 01 December 2012 (has links) (PDF)
ABSTRACT THE EFFECTS OF COLOR CONCENTRATES ON THE RHEOLOGY OF TINT BASES Douglas James Herrick Waterborne coatings are formulated with a number of different ingredients; water, latex polymers, pigments, surfactants, dispersants, defoamers, biocides, coalescing aids, and rheology modifiers or thickeners. Rheology modifiers are necessary in order to improve the physical properties of the coating before, during, and after application to a substrate. There are two kinds of rheology modifiers used in waterborne coatings; associative thickeners and non-associative thickeners. Coatings formulated with associative thickeners are quite sensitive to coating variations; the slightest change in the formulation has profound effects on the rheology of the coating. The opposite is true for coatings formulated with non-associative thickeners, where the rheology of the coating is not affected by minor changes in the formulation. The rheological properties of coatings are most influenced by the latex, thickener, and surfactant components of the coating. Previous studies have shown that the most ideal balance of rheological properties come from using associative thickeners. However, when waterborne coatings with associative thickeners are tinted with colorants containing high levels of surfactants they exhibit a significant decrease in viscosity. This change in viscosity results in poor sag resistance, poor brush loading, and may also cause a reduction in tint strength of the coating. In this work, the effect of tinting paints with six different colorants on the viscosity of the paint was studied for four different paint formulations: a pastel base and a deeptone base formulated with hydroxyethylcellulose (HEC-type) non-associative thickeners, and a pastel base and a deeptone base formulated with hydrophobically-modified, ethoxylated polyurethane (HEUR-type) associative thickeners. Gloss values and tinting strengths were obtained in accordance with ASTM methods D523-08 and D4838-88. In addition, dynamic stress and frequency sweeps were taken in order to study the effect of colorant addition on the viscoelastic properties of each sample. Colorant addition had little to no effects on the viscosity of the bases formulated with HEC thickeners, while there was a dramatic decrease in viscosity upon colorant addition to the bases with HEUR thickeners. Similar results were observed in the viscoelastic property analysis: little to no effects on the elastic and viscous moduli was seen with the tinted coatings formulated with the non-associative thickeners, while both the elastic and viscous moduli decreased for the coatings formulated with associative thickeners. A few of the deeptone bases showed increased moduli upon tinting compared to the parent deeptone base. The addition of colorant resulted in a decrease in tinting strength and an increase in gloss for those samples with associative thickeners, while the opposite was found for those samples with non-associative thickeners.
32

Local K-Core Algorithm in Complex Networks

Lu, Chen 21 October 2013 (has links)
No description available.
33

Disruption Information, Network Topology and Supply Chain Resilience

Li, Yuhong 17 July 2017 (has links)
This dissertation consists of three essays studying three closely related aspects of supply chain resilience. The first essay is "Value of Supply Disruption Information and Information Accuracy", in which we examine the factors that influence the value of supply disruption information, investigate how information accuracy influences this value, and provide managerial suggestions to practitioners. The study is motivated by the fact that fully accurate disruption information may be difficult and costly to obtain and inaccurate disruption information can decrease the financial benefit of prior knowledge and even lead to negative performance. We perform the analysis by adopting a newsvendor model. The results show that information accuracy, specifically information bias and information variance, plays an important role in determining the value of disruption information. However, this influence varies at different levels of disruption severity and resilience capacity. The second essay is "Quantifying Supply Chain Resilience: A Dynamic Approach", in which we provide a new type of quantitative framework for assessing network resilience. This framework includes three basic elements: robustness, recoverability and resilience, which can be assessed with respect to different performance measures. Then we present a comprehensive analysis on how network structure and other parameters influence these different elements. The results of this analysis clearly show that both researchers and practitioners should be aware of the possible tradeoffs among different aspects of supply chain resilience. The ability of the framework to support better decision making is then illustrated through a systemic analysis based on a real supply chain network. The third essay is "Network Characteristics and Supply Chain Disruption Resilience", in which we investigate the relationships between network characteristics and supply chain resilience. In this work, we first prove that investigating network characteristics can lead to a better understanding of supply chain resilience behaviors. Later we select key characteristics that play a critical role in determining network resilience. We then construct the regression and decision tree models of different supply chain resilience measures, which can be used to estimate supply chain network resilience given the key influential characteristics. Finally, we conduct a case study to examine the estimation accuracy. / Ph. D.
34

From individuals to ecosystems : a study of the temporal and spatial variation in ecological network structure

Henri, Dominic Charles January 2014 (has links)
Ecological network theory has developed from studies of static, binary trophic relationships to the analysis of quantitative, dynamic communities consisting of multiple link-types. Particularly, work has focused on the dynamic nature of ecological networks, which maintains stability in complex communities. However, there are few in situ network-level studies of the determinants of temporal and spatial variation in community structure. This thesis utilises data from a 10-year study of a host-parasitoid network and a collaborative study in an applied ecological setting to identify individual level factors important to network structure. The work aims towards an empirical, predictive framework linking adaptive foraging behaviour to ecological network structure. The results show that condition-dependent foraging behaviours structure host-parasitoid networks. The realised niches of the studied parasitoid species were generally biased towards larger host species and condition-dependent sex ratio allocation increased the likelihood that females would eclose from relatively larger hosts and males from relatively smaller hosts, which resulted in sex ratios deviating from Hamiltonian (50:50) predictions. Further, both of these aspects of behaviour are plastic, where parasitoid behaviour responded to environmental heterogeneity. Particularly, host preference behaviour conformed to an egg-/time-limitation framework, where the size dependency of the behaviour is greater when individuals have a greater likelihood of being egg-limited. Both the size-dependency and the plasticity of these behaviours differed significantly between secondary parasitoid species. This species identity effect interacted with landscape heterogeneity, which may explain some inter- and intra-specific variation in network structure. With respect to applied ecology, the results show that the benefits of natural vegetation for pest control are dependent upon the dispersal capabilities and the diet breadth of the pest and its natural enemies. The findings are evaluated towards a predictive framework for understanding the effects of future climate change on community structure and stability. We consider this framework in terms of applied ecology, particularly pest control ecosystem services provided by natural vegetation in an agricultural environment. The synergistic nature of the multiple determinants of network structure found in this thesis suggest that future studies should focus on the whole network, which is not necessarily the sum of its parts.
35

Photopolymerizations of multicomponent epoxide and acrylate/epoxide hybrid systems for controlled kinetics and enhanced material properties

Eom, Ho Seop 01 May 2011 (has links)
Cationic photopolymerization of multifunctional epoxides is very useful for efficient cure at room temperature and has been widely used in coatings and adhesives. Despite excellent properties of the final cured polymers, cationic photopolymerizations of epoxides have seen limited application due to slow reactions (relative to acrylates) and brittleness associated with a highly crosslinked, rigid network. To address these issues, two reaction systems were studied in this thesis: photoinitiated cationic copolymerizations of a cycloaliphatic diepoxide with epoxidized elastomers and acrylate/epoxide hybrid photopolymerizations. Oligomer/monomer structures, viscosity, compositions, and photoinitiator system were hypothesized to play important roles in controlling photopolymerizations of the epoxide-based mixtures. A fundamental understanding of the interplay between these variables for the chosen systems will provide comprehensive guidelines for the future development of photopolymerization systems comparable to the epoxide-based mixtures in this research. For diepoxide/oligomer mixtures, the observed overall enhancement in polymerization rate and ultimate conversion of the cycloaliphatic diepoxide was attributed to the activated monomer mechanism associated with hydroxyl terminal groups in the epoxidized oligomers. This enhancement increased with increasing oligomer content. The mixture viscosity influenced the initial reactivity of the diepoxide for oligomer content above 50 wt.%. Real-time consumption of internal epoxides in the oligomers was successfully determined using Raman spectroscopy. Initial reactivity and ultimate conversion of the internal epoxides decreased with increasing the diepoxide content. This trend was more pronounced for the oligomer containing low internal epoxide content. These results indicate that the reactivity of the hydroxyl groups is higher toward cationic active centers of the diepoxide than those of the internal epoxides in the oligomers. These conclusions are consistent with physical property results. The enhanced fracture toughness and impact resistance were attributed to multimodal network chain-length distribution of copolymers containing the oligomer content between 70% and 80%. For acrylate/epoxide hybrid mixtures, diacrylate oligomers significantly suppressed reactivities of cycloaliphatic mono/diepoxides, which was attributed to high mixture viscosity and highly crosslinked acrylate network. In this case, the dual photoinitiator system did not favor the epoxide reaction. Depending on the monovinyl acrylate secondary functionalities, enhanced reactivity and ultimate conversion of the diepoxide were attributed to a combined effect of a reduced viscosity and the radical-promoted cationic polymerization associated with the dual photoinitiator. The retarded and inhibited diepoxide reactivities with ether and urethane secondary groups were attributed to solvation and nucleophilicity/basicity effects, respectively. The influence of the diepoxide on the acrylate reactivity was attributed to dilution and polarity effects. In this case, high concentration of the free-radical photoinitiator is required for the dual photoinitiator system. Physical properties of hybrid polymers also varied with acrylate structures and monomer composition. Dynamic modulation methods were proposed to enhance the diepoxide reactivity and final properties in the presence of urethane acrylates.
36

Designing and evaluating distribution networks for luxury beds : A case study of Hästens Beds’ European distribution from the perspective of cost and delivery service

Huss, Sebastian, Normann, Arvid January 2023 (has links)
Hästens Beds is a Swedish luxury bed manufacturer, located in Köping, Sweden. They have a strong global presence, with Europe being the most mature and proven market. European retailers, called Hästens Partners, are serviced from the central warehouse in Borås which also handles all non-European export to Hästens’ other warehouse facilities in Hong Kong and the United States. As a part of Hästens’ planned growth journey, they are interested in reevaluating their European distribution network from a total cost and delivery service perspective. Hence, the purpose of this master’s thesis is to evaluate alternate distribution network designs in Europe for Hästens to reduce total logistics costs without impairing the delivery service level.  Extensive literature studies and initial interviews were conducted to understand both the theoretical field and the Hästens’ case-specific context. Based on this, three main research questions and a corresponding method resulted in a three-step approach to answer the purpose of the study.  In order to generate network structures and then analyze them, it was first necessary to determine the factors that should be included. Cost functions were created based on curve fitting, based on identified cost drivers for the included cost parameters of warehousing, transportation, and inventory carrying. Furthermore, the customer order lead time was concluded to be very generous. This had the consequence of the distribution lead time not putting any constraints on the network design. Lastly, access to transportation infrastructure, especially a port for handling the non-European export, and the general cost disparity between neighboring regions were concluded to be other important factors for the specific case of Hästens.  Center of gravity analyses based on the identified cost driver for outbound costs, m3-km, were then used to generate 13 candidate warehouse locations. In some cases, these locations were altered to better align with the identified important factors of good access to transportation infrastructure and cost disparity. The most strategically viable combinations of the number and echelons of warehouses could be limited to three combinations, all consisting of a single echelon with one, two, or three warehouses respectively. Therefore, three network optimization scenarios were created, minimizing the total cost of inbound and outbound transportation, which led to the generated network alternatives.  Finally, the total logistics costs were calculated and analyzed for the three alternative structures and a model replica of the current structure by utilizing the cost functions for each included cost parameter. The alternatives were also discussed based on delivery service theory and quantified with regard to distances to Partners. After applying sensitivity analysis and discussing the results’ implications for Hästens, Alternative 2* was formed with warehouses in Borås and Rotterdam. All the alternatives’ total logistics costs and average distances to Partners are quantified below.  [TABLE] As can be seen, the cost savings from Alternative 1 compared with the current network are marginal, and the costs of Alternative 2 and 2* are highly similar. Further, preliminary analysis showed that Alternative 2* would not be economically profitable until at least a 500% increase in European outbound transportation volumes. The conclusion that could be drawn from this was that Hästens is not yet suited to scale up its European distribution network to operate more than one warehouse. However, when future sales volumes allow for it, a European distribution center in Rotterdam could be profitable and provide European customers with greater delivery service.
37

Nätverk = Överlevnad? : En kvalitativ studie om småföretags nätverk och inkubatorns inverkan.

Cornelia, Karlsson, Johanna, Birgersson, Anna, Persson January 2022 (has links)
Småföretag har en väsentlig roll på Sveriges marknad där de tillför storaarbetsmöjligheter och står för hälften av Sveriges BNP. De står dock införutmaningar då de ofta brister på centrala kunskaper och resurser, och mångasmåföretag överlever endast ett fåtal år. Genom nätverkande kan småföretagenkomma åt de grundläggande tillgångarna men de har svårt att etablera ett stortoch betydelsefullt nätverk då de är små och okända på marknaden. Inkubatornsroll i samhället avser till att hjälpa småföretag att skapa en snabb tillväxt för attsedan kunna överleva själva ute på marknaden. Men det brister om förståelsekring hur småföretag arbetar med en inkubator samt hur småföretag kan skapamöjligheter för att utöka nätverket utifrån samarbetet med inkubatornsverksamhet, därav är det problemformuleringarna. Syftet för denna studie är attöka förståelse kring hur småföretagen kan främja deras nätverkande och hurinkubatorns verksamhet kan stödja och tillhandahålla resurser. För att kunna besvara studiens syfte och problemformuleringar har relevant teorioch empiri samlats in. Teorin finner att småföretagets interna och externanätverk är en väsentlig roll för överlevnad och tillväxt där entreprenörenspåverkan tydliggörs. För att utveckla ett välfungerande nätverk finner teorin attett samarbete tillsammans med inkubator och dess nätverk kan hjälpasmåföretaget. En egenkonstruerad modell förtydligar detta. Sista kapitletförklarar vad den teoretiska nätverksstrukturen kluster innebär och vad ettkluster kan möjliggöra för de aktörer som befinner sig inom strukturen. Detteoretiska kapitlet kompletteras med ett empiriskt kapitel. Den empiriskainsamlingen använder en kvalitativ metod där semistrukturerade intervjuer harutförts. Sex intervjuer genomfördes med grundare i varsitt småföretag som hareller just nu samarbetar med en inkubator. Den empiriska insamlingen gavskribenterna till denna studie en förståelse för vardera erfarenheter och socialaverklighet inom företagande och småföretagens nätverk kopplat till inkubatorn. Genom att sammanställa teori med empiri har dessa kunnat jämföras ochkopplas samman i ett analyskapitel. Analysen resulterade i en utveckling av denegenkonstruerade modellen från teorin där inkubatorn och kluster sammanfördesdå kopplingar mellan dessa uppkom under empirin. Slutsatsen visade på att detär av stor betydan att underhålla nätverksrelationerna inom småföretaget menockså med övriga entreprenörer och aktörer för att skapa nya och goda kontakter,både internt och externt. Där studien visade på att inkubatorns nätverksstrukturkluster, kan ses som en möjlighet för småföretagens tillväxt. Med brister på ettstrukturerat nätverk hos småföretagen finns risk att resurserna och tillgångarnapåverkas negativt samt att företaget kan gå miste om erfarenheter och nyainnovationer, vilket är något som studien har visat att inkubatorn kantillhandahålla för småföretagen. Det framkom även att den individuellaentreprenörens initiativtagande är väsentligt vad gäller ett småföretagsutveckling, framgång och förmåga att styra resultatet. / Small businesses have a significant role in the development of Sweden'smarkets, where they provide great job opportunities and are responsible for halfof Sweden's GDP. Small businesses face challenges as they often have a lack ofknowledge and resources. Small businesses can access the basic assets but theyhave difficulties establishing a large and significant network as they are smalland unknown in the market. In that case incubators can be of great use.Incubators help small businesses create a more rapid growth in order to then beable to survive independently on the market. According to the authors of thestudy there is a lack of understanding how small businesses work with anincubator and how small businesses can create opportunities to expand theirnetwork based on cooperation with the incubators. The problem statement andpurpose of this study are formulated to increase the understanding of how smallbusinesses can promote their network and how the incubators activities cansupport and provide resources. To be able to answer the purpose and the problem statement of this study,relevant theory and empirical data have been collected. The theoreticalframework finds that the small businesses internal and external networks areessential for survival and growth, where the entrepreneurs impact is clarified.To develop a well-functioning network, the theory finds that a collaborationwith the incubator and its network can aid small businesses. A self-designedmodel clarifies this. The theoretical framework also includes an explanation ofnetwork structured clusters, what defines a cluster, and the actors within thestructure. The empirical collection is made from a qualitative method wheresemi-structured interviews have been conducted. Six interviews were conductedwith founders from each small business who previously have or are currentlycollaborating with an incubator. The empirical collection gave the authors ofthis study an understanding of each small business' own experiences. By compiling the theory with the empirical data, it was possible to compare andlink the information in an analysis chapter. The analysis resulted in adevelopment of a self constructed model from the theory where the incubatorand cluster were brought together. The conclusion showed that it is of greatimportance to maintain the network relations within the small business but alsowith other entrepreneurs and actors to create new and beneficial contacts, bothinternally and externally. The study also showed that the incubators networkstructure and cluster can be seen as an opportunity for small business growth. Ifthere are deficiencies in a small business network there is a risk that resourcesand assets will be negatively affected and the company may lose experience andnew innovation, which is something that the study has shown that the incubatorcan provide for small businesses. It also emerged that the individualentrepreneurs initiative is essential in terms of small business development,success and ability to control the result.
38

Mathematical frameworks for quantitative network analysis

Bura, Cotiso Andrei 22 October 2019 (has links)
This thesis is comprised of three parts. The first part describes a novel framework for computing importance measures on graph vertices. The concept of a D-spectrum is introduced, based on vertex ranks within certain chains of nested sub-graphs. We show that the D- spectrum integrates the degree distribution and coreness information of the graph as two particular such chains. We prove that these spectra are realized as fixed points of certain monotone and contractive SDSs we call t-systems. Finally, we give a vertex deletion algorithm that efficiently computes D-spectra, and we illustrate their correlation with stochastic SIR-processes on real world networks. The second part deals with the topology of the intersection nerve for a bi-secondary structure, and its singular homology. A bi-secondary structure R, is a combinatorial object that can be viewed as a collection of cycles (loops) of certain at most tetravalent planar graphs. Bi-secondary structures arise naturally in the study of RNA riboswitches - molecules that have an MFE binary structural degeneracy. We prove that this loop nerve complex has a euclidean 3-space embedding characterized solely by H2(R), its second homology group. We show that this group is the only non-trivial one in the sequence and furthermore it is free abelian. The third part further describes the features of the loop nerve. We identify certain disjoint objects in the structure of R which we call crossing components (CC). These are non-trivial connected components of a graph that captures a particular non-planar embedding of R. We show that each CC contributes a unique generator to H2(R) and thus the total number of these crossing components in fact equals the rank of the second homology group. / Doctor of Philosophy / This Thesis is divided into three parts. The first part describes a novel mathematical framework for decomposing a real world network into layers. A network is comprised of interconnected nodes and can model anything from transportation of goods to the way the internet is organized. Two key numbers describe the local and global features of a network: the number of neighbors, and the number of neighbors in a certain layer, a node has. Our work shows that there are other numbers in-between the two, that better characterize a node. We also give explicit means of computing them. Finally, we show that these numbers are connected to the way information spreads on the network, uncovering a relation between the network’s structure and dynamics on said network. The last two parts of the thesis have a common theme and study the same mathematical object. In the first part of the two, we provide a new model for the way riboswtiches organize themselves. Riboswitches, are RNA molecules within a cell, that can take two mutually opposite conformations, depending on what function they need to perform within said cell. They are important from an evolutionary standpoint and are actively studied within that context, usually being modeled as networks. Our model captures the shapes of the two possible conformations, and encodes it within a mathematical object called a topological space. Once this is done, we prove that certain numbers that are attached to all topological spaces carry specific values for riboswitches. Namely, we show that the shapes of the two possible conformations for a riboswich are always characterized by a single integer. In the last part of the Thesis we identify what exactly in the structure of riboswitches contributes to this number being large or small. We prove that the more tangled the two conformations are, the larger the number. We can thus conclude that this number is directly proportional to how complex the riboswitch is.
39

協力治理、網絡結構與政策擴散: 以中國大陸森林認證政策為例 / Examining collaborative governance, network structure & policy diffusion: the case of forest certification policy in China

謝儲鍵, Hsieh, Chu Chien Unknown Date (has links)
面對全球氣候急遽變遷的挑戰下,各國政府對於環境治理議題高度的重視與 關切。在1992年京都議定書制定後,國家透過彼此的規範制約,期望可減少二 氧化碳的排放與環境的破壞。然而,正式權威途徑的執行,對於經濟發展與環境 永續的趨避衝突,卻不見預期效益。爾後,森林認證概念倡議後,希冀以市場途 徑作為國際規範,進入各國的創新管道。而第一個透過非政府組織建立的FSC體系,在2001年經由WWF進入中國大陸推展認證項目。只是,西方的運作思維與原則框架,在中國大陸終究遭遇到體制與管理上的困境。2008年後,中國大陸政府除了主導國家體系CFCC外,也與PEFC在2014年正式達成互認的成果。本研究試圖從政策改變前與後,以兩個階段分析行動者協力合作的情況,網 絡互動與體系採用的擴散情況。 研究結果分為兩個部分,首先就問卷統計數據來看協力與體系採用的相關性。對於FSC而言,治理與規範性是行動者選擇採用與否的重要因素。也就是行動者選擇FSC是因為重視認證資源的獲取、非正式關係的信任度與公開透明的正式溝通管道。而對於PEFC而言,治理因素同樣重要,而受到行動者支持的是相互性因數。傘型認證體制的特性,共同分享資訊、資源,使得政策場域中的行動者支持 PEFC。然而,對於CFCC而言並沒有太大的差異性。而在協力與網絡互動的分析上,自主性成為影響的因數。代表政策場域中的行動者,重視管理協調與主導政策制定討論的過程。 第二,對於擴散因數與體系採用的相關檢定。對FSC而言,社會化是重要 的關鍵。政策制定行動者考慮的是體系鄰近性、市場偏好、企業喜好與國際組織 的支持。而採用CFCC的行動者,同樣認為社會化重要。表示,利益方瞭解這是一個市場遊戲,而CFCC得到PEFC的互認後,對國家體系保持肯定態度。然而,競爭因素與採用CFCC也具有顯著性。表示行動者瞭解在中國大陸,政府透過管制帶來的競爭情勢,因此選擇了CFCC體系。 第三,就社會網絡分析數據分析,來看組織協力與體系採用關係。以程度中 心性來看,在資源與專業知識面向,皆是從國際組織轉向政府部門。在影響力層 面,國際組織甚至在第二階段便消失。而正式途徑的合作,以政府及國際組織為 兩大群體。但在第二階段,政府集中性更高,而國際組織則愈趨降低。包括在信 任度上,國際非政府組織也是下降的情況。在結構洞分析方面,第一階段的資源 掮客是一個多元組織的分佈,到的第二階段則單一化,國際體系成為傳達訊息的 角色。在影響力方面,第二階段主要是政府的角色成為掮客,而國際組織傳達影 響力的功能消失。而在信度度方面,第二階段發現國際非政府組織與企業,反而 更突顯他們在非正式關係網絡中的掮客位置。影響信任網絡的因素,分析發現政 策制定過程的資訊分享是關鍵原因。 本論文認為國際規範不僅建立在行動者的合作上,更需要結合地方組織,透 過社區力量建立由下而上的互動網絡。尤其第一階段,中國大陸需要藉由國際力 量,協助國內政策制定。因此,給予行動一個大鳴大放的空間與環境。第二階段, 受到協商過程的困境,而形成權力收回的情況。再者,中國大陸對於非政治敏感 議題,並非完全恪守政治命令而行,來決定政策發展的方向。相反的,政府可相 對釋出部分的自主性給國際組織。然而,當遭遇話語權問題時,便會透過管制途 徑收回權力,是一種「妥協式的管制協力」。而擴散的效應則是源於政策場域中, 行動者對於政策的學習與社會化而成。本研究透過微觀的實證資料,對中國大陸 協力、擴散與網絡互動研究有興趣的學者,提供另一個角度的解釋。總結來說, 國際規範透過非政府組織的「非正式途徑」,從國外帶入國內,並同時垂直向上 與向下影響中央政府的決策,及提升草根的公民力量。以中國大陸經驗反思國際 政策治理理論,重構對於開發中國家的「迴力鏢效應 2.0」模式。 / While facing the challenge of global climate change, each country puts much emphasis on environmental governance issues urgently. Since the Kyoto Protocol declared in 1992, the effective approach to resolve environmental crisis aims to regulate environmental standards and reduce emission of carbon dioxide through various air, forest and water management. However, the management efficiency is not obvious to enhance the sustainable target by formal authorities because of the conflict of economic development and environmental sustainability. The forest certification mechanism is an innovative business strategy to implement international norms into domestic governance. Particularly, FSC is successfully getting into China to develop systems through the strong support from international organizations and enterprises. On the other hand, FSC also confronted many obstacles in regulatory institution and management difficulties from Chinese registration and standard laws. Meanwhile, Chinese governments dominated in national system (CFCC) which had recognized with PEFC in 2014. This research analysis focused on the development of collaboration, network interaction and system adoption in two stages of policy change. First, the statistical findings show that norm and governance factors are significant to actors in adoption of FSC which means that the policy makers emphasize on the resource, informal trust relationships and transparent formal communication. Also, governance is important to actors to adopt PEFC systems. Another influential factor is mutuality that actors prefer the umbrella mechanism of PEFC to share information and resources with more flexible institutions. Otherwise, the correlation of interval variable of collaboration and network interaction, the analysis shows that autonomy is the influential factor to affect the collaborative relationships among actors in policy domain. On the other side, the interactive relationship is not significantly correlated to system adoption and diffusion. Second, about the results of diffusion and system adoption, socialization is a crucial element to support FSC because of system approximation, market preferences and INGO support. To CFCC adopters, socialization is also a significant factor to them which means that they understand the certification system is a global market game. After CFCC recognized with PEFC, policy-domain actors approve CFCC. Meanwhile, competition is a considerable dimension to actors by regulatory approach by central governments. Finally, based on network analysis of centrality, the high-central actors transformed to governmental actors from international NGOs in the second stage. Meanwhile, INGOs disappeared in influential factor. As for formal collaborative relationship, the public sectors and INGOs are two main groups. However, the public sectors are more central, but INGO are more peripheral. Also, the trust centrality of INGOs descends since CFCC and PEFC recognized. Of the structural-constraint analysis, the resource brokers are multiple in the first stage, but more homogeneous to public sector then. In policy-influence dimension, the governmental organizations are still main brokers in the second stage, and INGOs disappeared. The trust brokers are INGO and private sectors that highlight their informal relationships in the broker network. The Chinese governments release the approach of “airing views freely” to INGOs and multinational corporations in the first stage, and take back the autonomous right in second one because of “political baselines”. In conclusion, this research argues that collaborative governance not only requires the legitimacy of international norms and rules implemented to domestic markets, but also integrates more local actors in policy-making process to enhance the efficiency. Chinese governmental actors are willing to cooperate with others by releasing more power and autonomy. However, they also take back the power while they lose the power of discourse which means that it is “negotiable regulation and collaboration”. Moreover, the research results reform the “Boomerang Effect 2.0” to rethink about another vertical effect of INGOs power bringing into domestic central governments and local civil society.
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Network Analysis and Comparative Phylogenomics of MicroRNAs and their Respective Messenger RNA Targets Using Twelve Drosophila species

Woodcock, M Ryan 17 November 2010 (has links)
MicroRNAs represent a special class of small (~21–25 nucleotides) non-coding RNA molecules which exert powerful post-transcriptional control over gene expression in eukaryotes. Indeed microRNAs likely represent the most abundant class of regulators in animal gene regulatory networks. This study describes the recovery and network analyses of a suite of homologous microRNA targets recovered through two different prediction methods for whole gene regions across twelve Drosophila species. Phylogenetic criteria under an accepted tree topology were used as a reference frame to 1) make inference into microRNA-target predictions, 2) study mathematical properties of microRNA-gene regulatory networks, 3) and conduct novel phylogenetic analyses using character data derived from weighted edges of the microRNA-target networks. This study investigates the evidences of natural selection and phylogenetic signatures inherent within the microRNA regulatory networks and quantifies time and mutation necessary to rewire a microRNA regulatory network. Selective factors that appear to operate upon seed aptamers include cooperativity (redundancy) of interactions and transcript length. Topological analyses of microRNA regulatory networks recovered significant enrichment for a motif possessing a redundant link in all twelve species sampled. This would suggest that optimization of the whole interactome topology itself has been historically subject to natural selection where resilience to attack have offered selective advantage. It seems that only a modest number of microRNA–mRNA interactions exhibit conservation over Drosophila cladogenesis. The decrease in conserved microRNA-target interactions with increasing phylogenetic distance exhibited a cure typical of a saturation phenomena. Scale free properties of a network intersection of microRNA target predictions methods were found to transect taxonomic hierarchy.

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