Dissertations / Theses on the topic 'Structural diversity'
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McManus, Gregory J. "Structural diversity in metal-organic materials." [Tampa, Fla] : University of South Florida, 2008. http://purl.fcla.edu/usf/dc/et/SFE0002596.
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Doran, Michael B. "Structural diversity in organically templated uranium metals." Thesis, University of Oxford, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.413078.
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Holmes, Kathryn E. "Structural diversity within transition metal-sulfimide complexes." Thesis, Loughborough University, 2003. https://dspace.lboro.ac.uk/2134/35645.
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S,S'-diphenylsulfimide, Ph2SNH, 1, is an excellent ligand that readily forms N-bound complexes with a range of transition metals. Its importance as a ligand is enhanced by two significant features of the resulting complexes: (1) the strong hydrogen bonding interactions between the NH unit and the counterions; and (2) the ligand's ability to stabilise unusual structural combinations. By varying the counterions, the hydrogen bonding pattern can be changed and this affects the geometry at the metal centre. The anion also plays an important role in determining the coordination number of the metal. The hydrogen bonding interactions have been utilised to prepare extended arrays by the inclusion of appropriate outer sphere, bridging ligands, such as terephthalate and fumarate into the system. The fixation of atmospheric CO2 has been observed in a number of systems leading to the formation of both a bicarbonate dimer and a metal-bound carbonate ligand. These act as hydrogen bonding acceptors to give extended 2-D networks.
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Fullbrook, Jeremy Jon. "Generating structural diversity in α,α-difluoromethyl ketones." Thesis, University of Birmingham, 2003. http://etheses.bham.ac.uk//id/eprint/98/.
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This thesis describes attempts to use palladium-catalysed cross-coupling methodology in the synthesis of α,α-difluoroketones contained within a diverse array of molecular motifs. 1-(N,N-Diethylcarbamoyloxy)-2,2-difluoro-1-(tributylstannyl)ethene undergoes Stille cross coupling with a variety of aryl, heteroaryl, vinyl and allyl organic electrophiles. Conditions, which promote in situ transmetallation to a more reactive copper intermediate, were essential for obtaining significant quantities of product. 1-(N,N-Diethylcarbamoyloxy)-2,2-difluoro-1-iodoethene also underwent coupling with a range of aryl, heteroaryl and vinyl stannanes. Due to the difficulties with cleavage of this protecting group, the synthesis and potential application of an N-ethyl-N-(2-methylallyl)carbamate has been studied. A 2-methoxyethoxymethyl (MEM) protecting group strategy proved very successful for the synthesis of a range of difluoromethyl aryl ketones. Two consecutive coupling reactions were possible from a difluoroenol stannane, in which coupling of initial styrene products bearing a triflate group afforded a range of biarylethenes. Cleavage occurred under mild electrophilic conditions with protic, halogen, sulfur and carbon electrophiles. Diene products have been tested for reactivity in Sharpless Asymmetric Dihydroxylation. A 1,4-diene has been converted through to a fluorinated analogue of a dideoxyxylulose. A 1,3-diene has been successfully converted through to a difluorodeoxyxylulose of current interest. Key points involve regioselective and highly enantioselective dihydroxylation of the non-fluorinated olefin. Application of a special protecting group for the allylic alcohol was essential, as was control of the pH of the reaction medium.
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Medeiros, José António Amaro Correia. "Optimal sample size for assessing bacterioneuston structural diversity." Master's thesis, Universidade de Aveiro, 2011. http://hdl.handle.net/10773/10901.
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Mestrado em Biologia Aplicada - Microbiologia Clínica e AmbientalThe surface microlayer (SML) is located at the interface atmospherehydrosphere and is theoretically defined as the top millimeter of the water column. However, the SML is operationally defined according to the sampling method used and the thickness varies with weather conditions and organic matter content, among other factors. The SML is a very dynamic compartment of the water column involved in the process of transport of materials between the hydrosphere and the atmosphere. Bacterial communities inhabiting the SML (bacterioneuston) are expected to be adapted to the particular SML environment which is characterized by physical and chemical stress associated to surface tension, high exposure to solar radiation and accumulation of hydrophobic compounds, some of which pollutants. However, the small volumes of SML water obtained with the different sampling methods reported in the literature, make the sampling procedure laborious and time-consuming. Sample size becomes even more critical when microcosm experiments are designed. The objective of this work was to determine the smallest sample size that could be used to assess bacterioneuston diversity by culture independent methods without compromising representativeness and therefore ecological significance. For that, two extraction methods were tested on samples of 0,5 mL, 5 mL and 10 mL of natural SML obtained at the estuarine system Ria de Aveiro. After DNA extraction, community structure was assessed by DGGE profiling of rRNA gene sequences. The CTAB-extraction procedure was selected as the most efficient extraction method and was later used with larger samples (1 mL, 20 mL and 50 mL). The DNA obtained was once more analyzed by DGGE and the results showed that the estimated diversity of the communities does not increase proportionally with increasing sample size and that a good estimate of the structural diversity of bacterioneuston communities can be obtained with very small samples.
A microcamada superficial marinha (SML) situa-se na interface atmosferahidrosfera e teoricamente é definida como o milímetro mais superficial da coluna de água. Operacionalmente, a espessura da SML depende do método de amostragem utilizado e é também variável com outros fatores, nomeadamente, as condições meteorológicas e teor de matéria orgânica, entre outros. A SML é um compartimento muito dinâmico da coluna de água que está envolvida no processo de transporte de materiais entre a hidrosfera e a atmosfera. As comunidades bacterianas que habitam na SML são designadas de bacterioneuston e existem indícios de que estão adaptadas ao ambiente particular da SML, caracterizado por stresse físico e químico associado à tensão superficial, alta exposição à radiação solar e acumulação de compostos hidrofóbicos, alguns dos quais poluentes de elevada toxicidade. No entanto, o reduzido volume de água da SML obtidos em cada colheita individual com os diferentes dispositivos de amostragem reportados na literatura, fazem com que o procedimento de amostragem seja laborioso e demorado. O tamanho da amostra torna-se ainda mais crítico em experiências de microcosmos. O objectivo deste trabalho foi avaliar se amostras de pequeno volume podem ser usadas para avaliar a diversidade do bacterioneuston, através de métodos de cultura independente, sem comprometer a representatividade, e o significado ecológico dos resultados. Para isso, foram testados dois métodos de extracção em amostras de 0,5 mL, 5 mL e 10 mL de SML obtida no sistema estuarino da Ria de Aveiro. Após a extracção do DNA total, a estrutura da comunidade bacteriana foi avaliada através do perfil de DGGE das sequências de genes que codificam para a sub unidade 16S do rRNA. O procedimento de extracção com brometo de cetil trimetil de amônia (CTAB) foi selecionado como sendo o método de extração com melhor rendimento em termos de diversidade do DNA e mais tarde foi aplicado a amostras de maior dimensão (1 mL, 20 mL e 50 mL). O DNA obtido foi mais uma vez usado para análise dos perfis de DGGE de 16S rDNA da comunidade e os resultados mostraram que a estimativa da diversidade de microorganismos não aumentou proporcionalmente com o aumento do tamanho da amostra e que com amostras de pequeno volume podem ser obtidas boas estimativas da diversidade estrutural das comunidades de bacterioneuston.
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Abourahma, Heba. "Structural diversity in metal-organic nanoscale supramolecular architectures." [Tampa, Fla.] : University of South Florida, 2004. http://purl.fcla.edu/fcla/etd/SFE0000336.
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Corum, Aaron K. "Sixteen valence-electron species containing boron structural diversity abounds /." Diss., Columbia, Mo. : University of Missouri-Columbia, 2005. http://hdl.handle.net/10355/4303.
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Thesis (M.S.)--University of Missouri-Columbia, 2005.The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file viewed on (July 13, 2006) Includes bibliographical references.
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Nakamura, Yasuyuki. "Exploration of Structural Diversity of Directly Linked Porphyrin Arrays." 京都大学 (Kyoto University), 2008. http://hdl.handle.net/2433/124483.
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O'Daniel, Peter Ivo. "Exploring structural diversity in nucleoside and nucleic acid drug design." Diss., Available online, Georgia Institute of Technology, 2005, 2005. http://etd.gatech.edu/theses/available/etd-08252005-130946/.
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Thesis (Ph. D.)--Chemistry and Biochemistry, Georgia Institute of Technology, 2006.Barefield, E. Kent, Committee Member ; Beckham, Haskell W., Committee Member ; Doyle, Donald F., Committee Member ; Weck, Marcus, Committee Member ; Seley, Katherine L., Committee Chair.
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Monnais, Edouard. "Structural and functional diversity of flagellins expressed by gut bacteria." Thesis, University of Aberdeen, 2013. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=202130.
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Flagellins are proteins of microbial origin that confer motility to bacteria. They exhibit a stupendous conservation in their structure, required for assembly into polymeric flagella. The various environmental and evolutionary pressures encountered by motile bacteria have however generated a multiplicity of primary protein sequences. In mammals, specific receptors, namely TLR5 and Ipaf, are devoted to the immunosurveillance of flagellins. We sought to explore the diversity of flagellin structures expressed by the intestinal microbiota and how these proteins may influence the host innate immune response. In this context, recombinant flagellins derived from Gram-negative and Gram-positive, pathogenic and commensal bacteria from the γ-Proteobacteria and the Clostridium sub-phyla were expressed in E.coli and then purified. Protein sequence alignment and phylogenetic analysis of twelve flagellins revealed clustering dependent on three criteria: the phylum, the genus and the commensal or pathogenic nature of the bacteria. We next characterized these structures functionally using in vitro cell systems including epithelial and dendritic cells. In a TLR5-dependent manner, flagellin induced the secretion of pro-inflammatory chemokines in intestinal epithelial cells, which are considered crucial in triggering the recruitment of immune cell effectors. Of importance, the secretion levels were directly dependent of the flagellin structure, as confirmed by the various agonistic potentials determined in dose-response experiments. We observed that commensal flagellins were in general less potent than pathogenic flagellins. Similarly, the effects on dendritic cells following flagellin exposure were ligand-dependent. Overall, TLR5 activation constitutes a ligand-dependent TLR5-flagellin complex formation with sequential activation of MAPK and/or NF-kB and signalling, resulting in differential modulation of the intracellular signalling cascade downstream. The results presented in this thesis suggest innate signalling mediated by flagellated pathogens and commensals may affect the intestinal immune status in a number of distinct ways, either by promoting active immune response or by promoting tolerance response.
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Yan, Yuncheng. "Exploring and analysing the structural diversity of organic co-crystals." Thesis, Cardiff University, 2014. http://orca.cf.ac.uk/66247/.
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Organic co-crystals are a class of promising materials in industries such as pharmaceuticals and energy industry. The work described in this thesis is the result of studying a series of organic co-crystals, which are synthesized by several different crystallization methods, and includes structures determined by single-crystal X-ray diffraction and powder X-ray diffraction. Chapter 1 is a general introduction to organic co-crystals and the phenomenon of polymorphism in organic crystalline materials. The importance of intermolecular interactions such as hydrogen bonding and π-π stacking interactions for the design of organic co-crystals are also highlighted. Chapter 2 describes the experimental techniques which have been used for studying organic co-crystals. These include co-crystallization methods and characterization methods such as single-crystal X-ray diffraction, powder X-ray diffraction, thermal analysis techniques and solid-state nuclear magnetic resonance. Chapter 3 reports two novel polymorphic co-crystal systems of trimesic acid (TMA) and tert-butylamine (TBA) with different stoichiometric ratios and analyses the crystal structures of the two polymorphic systems. Apart from the phenomenon of polymorphism of co-crystals of TMA and TBA, the structural diversity of other co-crystals of TMA and TBA are discussed in Chapter 4. In this chapter, all co-crystals of TMA and TBA are classified into four families based on the stoichiometric ratio between TMA and TBA, and the structural features of each family are investigated from the view point of hydrogen bonding with graph set notation. Chapters 5 and 6 demonstrate the processes of structure determination of co-crystals of TMA and ʟ-arginine (Chapter 5) and the co-crystal of pillar[5]quinone and 1,1,2,2-tetrachloroethane (Chapter 6) from powder X-ray diffraction data.
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Murase, Shigemitsu. "Structural Diversity and Molecular Orientation in Polyester and Polyamide Fibers." Kyoto University, 1997. http://hdl.handle.net/2433/202320.
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Mrkonjic, Fuka Mirna. "Structural and functional diversity of proteolytic genes in an arable field." kostenfrei, 2006. http://mediatum2.ub.tum.de/doc/620023/document.pdf.
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Storch, Felix [Verfasser], Jürgen [Akademischer Betreuer] Bauhus, and Carsten F. [Akademischer Betreuer] Dormann. "Influence of harvesting intensity on species and structural diversity of forests." Freiburg : Universität, 2018. http://d-nb.info/1172203342/34.
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Stockwell, Gareth Rhys. "Structural diversity of biological ligands and their binding sites in proteins." Thesis, University College London (University of London), 2005. http://discovery.ucl.ac.uk/1432660/.
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The phenomenon of molecular recognition, which underpins almost all biological processes, is dynamic, complex and subtle. Establishing an interaction between a pair of molecules involves mutual structural rearrangements guided by a highly convoluted energy landscape, the accurate mapping of which continues to elude us. The analysis of interactions between proteins and small molecules has been a focus of intense interest for many years, offering as it does the promise of increased insight into many areas of biology, and the potential for greatly improved drug design methodologies. Computational methods for predicting which types of ligand a given protein may bind, and what conformation two molecules will adopt once paired, are particularly sought after. The work presented in this thesis aims to quantify the amount of structural variability observed in the ways in which proteins interact with ligands. This diversity is considered from two perspectives: to what extent ligands bind to different proteins in distinct conformations, and the degree to which binding sites specific for the same ligand have different atomic structures. The first study could be of value to approaches which aim to predict the bound pose of a ligand, since by cataloguing the range of conformations previously observed, it may be possible to better judge the biological likelihood of a newly predicted molecular arrangement. The findings show that several common biological ligands exhibit considerable conformational diversity when bound to proteins. Although binding in predominantly extended conformations, the analysis presented here highlights several cases in which the biological requirements of a given protein force its ligand to adopt a highly compact form. Comparing the conformational diversity observed within several protein families, the hypothesis that homologous proteins tend to bind ligands in a similar arrangement is generally upheld, but several families are identified in which this is demonstrably not the case. Consideration of diversity in the binding site itself, on the other hand, may be useful in guiding methods which search for binding sites in uncharacterised protein structures: identifying those regions of known sites which are less variable could help to focus the search only on the most important features. Analysis of the diversity of a non-redundant dataset of adenine binding sites shows that a small number of key interactions are conserved, with the majority of the fragment environment being highly variable. Just as ligand conformation varies between protein families, so the degree of binding site diversity is observed to be significantly higher in some families than others. Taken together, the results of this work suggest that the repertoire of strategies produced by nature for the purposes of molecular recognition are extremely extensive. Moreover, the importance of a given ligand conformation or pattern of interaction appears to vary greatly depending on the function of the particular group of proteins studied. As such, it is proposed that diversity analysis may form a significant part of future large-scale studies of ligand-protein interactions.
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Park, Sungkyu. "Cyclotides evolve : Studies on their natural distribution, structural diversity, and activity." Doctoral thesis, Uppsala universitet, Avdelningen för farmakognosi, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-292668.
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The cyclotides are a family of naturally occurring peptides characterized by cyclic cystine knot (CCK) structural motif, which comprises a cyclic head-to-tail backbone featuring six conserved cysteine residues that form three disulfide bonds. This unique structural motif makes cyclotides exceptionally resistant to chemical, thermal and enzymatic degradation. They also exhibit a wide range of biological activities including insecticidal, cytotoxic, anti-HIV and antimicrobial effects. The cyclotides found in plants exhibit considerable sequence and structural diversity, which can be linked to their evolutionary history and that of their host plants. To clarify the evolutionary link between sequence diversity and the distribution of individual cyclotides across the genus Viola, selected known cyclotides were classified using signature sequences within their precursor proteins. By mapping the classified sequences onto the phylogenetic system of Viola, we traced the flow of cyclotide genes over evolutionary history and were able to estimate the prevalence of cyclotides in this genus. In addition, the structural diversity of the cyclotides was related to specific features of the sequences of their precursor proteins, their evolutionary selection and expression levels. A number of studies have suggested that the biological activities of the cyclotides are due to their ability to interact with and disrupt biological membranes. To better explain this behavior, quantitative structure-activity relationship (QSAR) models were developed to link the cyclotides’ biological activities to the membrane-interactive physicochemical properties of their molecular surfaces. Both scalar quantities (such as molecular surface areas) and moments (such as the distributions of specific properties over the molecular surface) were systematically taken into account in the development of these models. This approach allows the physicochemical properties of cyclotides to be geometrically interpreted, facilitating the development of guidelines for drug design using cyclotide scaffolds. Finally, an optimized microwave-assisted Fmoc-SPSS procedure for the total synthesis of cyclotides was developed. Microwave irradiation is used to accelerate and improve all the key steps in cyclotide synthesis, including the assembly of the peptide backbone by Fmoc-SPPS, the cleavage of the protected peptide, and the introduction of a thioester at the C-terminal carboxylic acid to obtain the head-to-tail cyclized cyclotide backbone by native chemical ligation.
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Sharman, James William 1963. "Management effects on structural diversity in oak woodlands of southeastern Arizona." Thesis, The University of Arizona, 1992. http://hdl.handle.net/10150/278154.
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Measurements of tree characteristics were used as indicators of overstory structure on four oak woodland sites in southeastern Arizona. Three areas harvested at different times and intensities were compared with an undisturbed area to assess effects of harvesting on various structural attributes of woodland overstories. Structural vegetation changes affect habitat quality and thus wildlife populations in modified areas. Significant differences were found for some woodland structural characteristics between harvested areas and an undisturbed area. Structural changes persist, as prolific coppice sprouting produces shrub-like trees, which appear to take a relatively long time to reach mature height and form. Managers might be able to moderate impacts of harvests on woodland structure by adjusting harvest intensity, and multiple-use management objectives for some species of wildlife still might be met.
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Angelo, James J. "Characterizing the vertical structure and structural diversity of Florida oak scrub vegetation using discrete-return lidar." Master's thesis, University of Central Florida, 2010. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/4539.
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Vertical structure, the top-to-bottom arrangement of aboveground vegetation, is an important component of forest and shrubland ecosystems. For many decades, ecologists have used foliage height profiles and other measures of vertical structure to identify discrete stages in post-disturbance succession and to quantify the heterogeneity of vegetation. Such studies have, however, required resource-intensive field surveys and have been limited to relatively small spatial extents (e.g., less than]15 ha). Light detection and ranging (lidar) is an active remote sensing technology with enormous potential to characterize the three-dimensional structure of vegetation over broad spatial scales. In this study, discrete-return lidar data were used to create vertical profiles for over 500 vegetation patches on approximately 1000 ha of an oak scrub landscape in the Kennedy Space Center/Merritt Island National Wildlife Refuge area on the east-central coast of Florida. Nonparametric multivariate analysis of variance (NPMANOVA) tests detected significant differences among the profiles belonging to the four predominant land use/land cover (LULC) types in the study area. For the dominant LULC category (Herbaceous upland non-forested), pairwise NPMANOVA comparisons indicated that there were significant differences between vertical profiles for some of the distinct time since fire (TSF) values. Measures of vertical structural diversity (VSD) were calculated from the vertical profiles and then null, linear, and quadratic models relating VSD to TSF were compared via an Akaike information criterion (AIC) model selection procedure. As predicted by the Intermediate Disturbance Hypothesis, the quadratic model was the best model for the Herbaceous upland non-forested LULC category, but it explained less than 3% of the total variation in VSD.; When fire frequency was considered in conjunction with TSF for this LULC category, however, the model that was quadratic in both predictor variables was the best model among the candidates and explained over 6% of the total variation in VSD. These results support the Extended Keystone Hypothesis, which predicts that disturbance generates discrete structural patterns across landscapes, and the Intermediate Disturbance Hypothesis, since the VSD of the predominant LULC category was maximized at intermediate levels of fire disturbance (i.e., intermediate values of TSF and/or fire frequency). In addition to demonstrating the ability of discrete-return lidar to characterize the vertical structure of vegetation at the landscape scale, this research has potential management implications. Using the techniques developed in this study, practitioners can compare the vertical structure of managed ecosystems to reference natural systems to evaluate the efficacy of managed disturbance regimes.ID: 029094364; System requirements: World Wide Web browser and PDF reader.; Mode of access: World Wide Web.; Thesis (M.S.)--University of Central Florida, 2010.; Includes bibliographical references (p. 42-47).
M.S.
Masters
Department of Biology
Sciences
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Varadan, Ranjani. "NMR studies of polyubiquitin chains insights into structural basis of functional diversity /." College Park, Md. : University of Maryland, 2004. http://hdl.handle.net/1903/1959.
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Thesis (Ph. D.) -- University of Maryland, College Park, 2004.Thesis research directed by: Biochemistry. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
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Dănescu, Adrian [Verfasser], Jürgen [Akademischer Betreuer] Bauhus, and Ulrich [Akademischer Betreuer] Kohnle. "Structural diversity as a driver of growth dynamics in irregular, mixed forests." Freiburg : Universität, 2018. http://d-nb.info/1171928467/34.
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Cheng, Johnathan Zandrew. "Nature's approach toward ring formation and structural diversity in ergot alkaloid biosynthesis." Thesis, Massachusetts Institute of Technology, 2011. http://hdl.handle.net/1721.1/65472.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemistry, 2011.Vita. Cataloged from PDF version of thesis.
Includes bibliographical references.
Ergot alkaloids are fungal-derived secondary metabolites well known for a diverse array of pharmacological effects both beneficial and detrimental to human health. Historically, the ergot alkaloids have been known to cause ergotism in populations that consume grain contaminated by ergot alkaloid producing fungus. However, naturally isolated and semi-synthetic derivatives of certain ergot alkaloids have also been used to treat migraines, Parkinsonism, and tumor growth. Different fungal species such as Aspergillusfumigatus, Claviceps purpurea, and Neotyphodium lolii produce ergot alkaloids that have distinct structural features yet share a common tetracyclic ergoline ring scaffold. Mechanistic details regarding the formation of the common ergoline ring are not well understood, though the genes encoding the enzymes that carry out these cyclizations are believed to be well conserved across divergent fungal species. Here we describe in vivo gene disruption experiments in Aspergillusfumigatus that allowed us to identify candidate enzymes that were directly involved with the intramolecular cyclization of the ergoline ring. Additionally, we discuss the cloning and heterologous expression of these genes to further characterize their catalytic function. Old Yellow Enzyme homologues from the ergot gene clusters of Aspergillus fumigatus and Neotyphodium loii were shown to catalyze the formation of the D ring of the ergoline skeleton. These enzymes catalyzed either reductase or isomerase type reactions to yield distinct pathway intermediates. Mutational analysis was used to engineer an Old Yellow Enzyme that displayed both reductase and isomerase activities, thereby elucidating the mechanistic basis behind this switch in enzymatic activity. These findings present a mechanistic rationale behind nature's biosynthetic strategy toward ring cyclization and the introduction of structural diversity into the ergot alkaloid class of natural products.
by Johnathan Zandrew Cheng.
Ph.D.
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Storey, Sylvana Clare. "The impact of diversity on global leadership performance." Thesis, University of Manchester, 2013. https://www.research.manchester.ac.uk/portal/en/theses/the-impact-of-diversity-on-global-leadership-performance(50235e16-7445-4602-a81d-34149241a6a0).html.
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Purpose: The focus of this research is to understand the impact of diversity on global leadership performance. Design/methodology/approach: From the literature review the researcher developed the components of the LEAD³ tool as well as, devised the questions for the in-depth semi-structured interviews that would test the tool. The questions centred on the three constructs of leadership, diversity and organisational factors and interviews were conducted between 2009 and 2010. The sample consisted of 79 senior leaders from seven companies across seven differing sectors and covered 22 different countries across 5 continents. A case study research strategy using a hybrid of open coding, thematic analysis and content analysis was employed. Findings: A series of themes were found under the three constructs: For Global leadership – competencies, connecting, rigour, stakeholder satisfaction, value based professional, influences. For Diversity – inclusivity, performance measures, role modelling, positioning diversity and innovation. For Organisational factors – organisational way of being, facilitating diversity, behavioural practices, ways of working, issues of concern and driving diversity. Issues emerging from the comparative analysis consist of cultural dimensions, engagement and learning. Research Limitations: Issues on reliability and validation, translation in measurement, environmental inconsistency, interviewer/interviewee bias, and ecological fallacy often levied at qualitative research. Research Contribution and Value: The findings tested against the tool, confirm the robustness and relevancy of the LEAD³ as an operational tool that will enable leaders to focus and integrate their diversity efforts. LEAD³ is encapsulated within an integrated change management framework and proposes a multi-level and multi-dimensional approach to global leadership and diversity that also includes performance drivers, stakeholder groupings, performance outcomes and organisational activities (change interventions). Future Research:Finally, an attempt is made to develop a competency framework for leadership and diversity from data emerging from findings. This is named the Global Leader Index for Diversity (GLIDE) – a framework that recognises the diverse aspects of a global leader’s role and identifies associated skills and behaviours that global leaders of the future need to develop.
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Bolsinger, Jens [Verfasser]. "New insights into the reactivity and structural diversity of organotellurium compounds / Jens Bolsinger." Berlin : Freie Universität Berlin, 2012. http://d-nb.info/1027309364/34.
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Mahmoud, Huda Mahmoud Abdullah. "Structural and functional diversity of epilithic bacterial communities in streams : effects of pollution." Thesis, University of Hull, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.271992.
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Martin, Sarah L. "Quantifying the effect of microbial diversity and plant roots on soil structural development." Thesis, University of Nottingham, 2010. http://eprints.nottingham.ac.uk/11355/.
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Soil is one of the most complex ecosystems in the environment and changes to microbial diversity are thought to affect the physical structure (and vice versa). A fundamental question addressed in this research, is how microbial communities influence the functioning of soil, particularly with respect to the development and maintenance of a soil’s physical structure. Using micro- and macrocosms of sieved (and therefore structureless) soil, the effects of time, soil texture, manipulated background microbial diversity, and Plantago lanceolata (± mycorrhizal fungi) on the development of soil structure were determined. Background microbial diversity was manipulated using the dilution technique to give a low (101) dilution or a high (106) dilution of the original soil. This resulted in greater bacterial diversity in the lower (101) dilution than in the higher (106) dilution when in the presence of mycorrhizal plants. However, background diversity was the same irrespective of dilution in soils with non-mycorrhizal plants (and reversed within the bare soil). Micro- and macrocosms were continually assessed during controlled incubation periods ranging from 7 weeks to 15 months. Of the soil textures analysed (clay loam, loamy sand and sandy loam), loamy sand displayed the highest overall porosity as well as a noteworthy development in porosity throughout the incubation period. Mycorrhizal and nonmycorrhizal plants increased the speed of soil structural development by 5 months relative to unplanted soils. Although mycorrhizal fungi stunted root growth initially, aggregates within mycorrhizal planted treatments were smaller but nonetheless more stable than those in bare soil. Increasing mycorrhizal fungal species richness enhanced root and shoot biomass and reduced aggregate size and total porosity. There was a positive relationship between total porosity and numbers of culturable bacteria and fungi. In soils containing a lower microbial diversity, an increase in porosity, mean pore size, aggregate size and pore perimeter was observed. Results obtained were dependent on incubation conditions, planting regime and mycorrhizal status. Therefore, the effects of reducing microbial species diversity on soil structure parameters are idiosyncratic, with the presence of plant roots acting as a key factor.
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Shillam, Laura-Lee. "Structural diversity and decomposition functions of volcanic soils at different stages of development." Thesis, University of Stirling, 2008. http://hdl.handle.net/1893/444.
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During a volcanic eruption, the extrusion of lava onto surfaces destroys biological activity creating virgin land surfaces. Through time this new land will be subject to soil formation and colonisation under relatively similar climatic conditions and parent materials. Soils formed from volcanic deposits present a unique opportunity to study microbial community development. Soils at different developmental stages and differing in vegetation cover were selected from four locations on the slopes of Mount Etna, Sicily. Three main research objectives were determined in order to test the hypothesis that the microbial communities from soils at later stages of development would have a greater biomass, be more diverse, be more efficient at utilising carbon sources and recover from an environmental disturbance at a greater rate. A field experiment was conducted to ascertain the long term in situ catabolic abilities of the microbial communities in each soil and to establish the effects of litter mixing on decomposition rate. Litter bags containing either Genista aetnensis (Etnean Broom), Pinus nigra (Corsican Pine) or a mixture of the two were buried at each of the sites and their decomposition monitored over a 2.5 year period. PLFA diversity, community composition and function was assessed for each of the soils. The soils were also subject to a disturbance and the recovery of key community parameters was monitored over a six month period in order to establish each soil community’s resistance and resilience to disturbance. A laboratory experiment was conducted in order to investigate functional diversity and decomposition functions of each soil community using a range of simple and complex substrates. The relationship between PLFA diversity and functional diversity was also investigated. No correlation was found between soil C and N contents, microbial biomass or soil respiration and soil developmental stage and there was no detectable difference in litter bag mass loss between the soil types. No non- additive effects were noted in mixed litters. The more developed soil had a greater PLFA diversity and PLFA biomass however the more developed soil was not more resistant or resilient to disturbance. Developed soils showed greater catabolic diversity compared with less developed soils broadly correlating with PLFA diversity. Despite increased PLFA diversity and functional diversity in the more developed soils, residue decomposition in situ was unaffected. Reduced PLFA diversity and community complexity did not result in reduced function. Soils at different developmental stages had similar catabolic responses and were able to degrade simple and complex substrates to a similar degree. Microbial diversity in soil has the potential to be very high thus resulting in a high rate of functional redundancy i.e. many species within the same community which have the same functional role. It is possible that only a few key functional groups present within the soil community contribute to the main decomposition function within the soil and were able to maintain function during perturbation. Both Etna soils had similar PLFA’s present in similar concentrations and these groups in general were maintained during disturbance. This suggests that total microbial community diversity may not be as important to community function as the presence of key functional groups.
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Bolsinger, Jens Roland [Verfasser]. "New insights into the reactivity and structural diversity of organotellurium compounds / Jens Bolsinger." Berlin : Freie Universität Berlin, 2012. http://nbn-resolving.de/urn:nbn:de:kobv:188-fudissthesis000000037581-6.
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Kodan, Atsushi. "Structural and Functional Diversity of Stilbene Synthases from Japanese Red Pine(Pinus densiflora)." Kyoto University, 2002. http://hdl.handle.net/2433/149934.
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Kyoto University (京都大学)0048
新制・課程博士
博士(農学)
甲第9649号
農博第1277号
新制||農||847(附属図書館)
学位論文||H14||N3681(農学部図書室)
UT51-2002-G407
京都大学大学院農学研究科応用生命科学専攻
(主査)教授 酒井 富久美, 教授 坂田 完三, 教授 島田 幹夫
学位規則第4条第1項該当
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Sharma, Shilpi. "Structural and functional characterization of bacterial diversity in the rhizospheres of three grain legumes." Diss., lmu, 2004. http://nbn-resolving.de/urn:nbn:de:bvb:19-24790.
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Månsson, Martin. "The structural diversity of lipopolysaccharides expressed by genetically defined clinical isolates of nontypeable Haemophilus influenzae /." Stockholm, 2003. http://diss.kib.ki.se/2003/91-7349-584-0.
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Huynh, Kevin Weijian. "Structural Analysis of TRPV2 by Cryo-Electron Microscopy Reveals Regulatory Diversity Among the ThermoTRPV Channels." Case Western Reserve University School of Graduate Studies / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=case1467996438.
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Courtney, Steven. "Investigating school leadership at a time of system diversity, competition and flux." Thesis, University of Manchester, 2015. https://www.research.manchester.ac.uk/portal/en/theses/investigating-school-leadership-at-a-time-of-system-diversity-competition-and-flux(c3c52eb8-8bfb-4a16-b54b-f401b42939b8).html.
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This dissertation reports on a qualitative study of school leadership with nine secondary-school headteachers (of maintained schools) or principals (of academy-type schools) in England. The project maps schooling provision and offers an empirical account of leaders’ identities and practices in neoliberal and neoconservative times. Informed by a critical policy-scholarship methodology, documentary data from primary and secondary sources supplement narrative and semi-structured interviews conducted over 18 months. The findings are reported in five journal articles and one book chapter. The first output maps school types through different lenses: legal status; curriculum; selection; types of academy; and school groupings. The mapping highlights the intersections between the reform agenda and historical diversity. I conceptualise the landscape holistically through locus of legitimacy and branding, arguing that diversification policies facilitate corporatised and religious interests. Second, I show how UTCs and studio schools construct children’s abilities as fixed and differentiable in terms of predicted economic value. They select, but the responsibility for this, following Bourdieu, is transferred discursively from the school through branding and habitus to the “consumers” where it is to be misrecognised as exercising ‘school choice’. Third, I typologise three effects on heads’ and principals’ agency and identities of a few elite multi-academy trust principals, or courtiers, who have won regional empires through expanding their academy chains to occupy the spaces opened up by the dismantling of LAs. Public-sector and school-leader identities and histories permit the promotion of their activities as “school led” and downplays their close relationship with central-state policy makers and private-sector networks. Fourth, I argue that corporatised leadership in schools in England is being promoted through new actors and new types of school. Corporatised leadership is characterised inter alia by the promotion of business interests and the adoption of business-derived leadership practices and identities. I use Bourdieu’s concept of field to explain the impact of business on educational leadership and the dissonance between leaders and led. Fifth, I argue with Gunter that school leaders are removing those who embody or vocalise alternative conceptualisations of educator by eradicating ‘inadequate’ teaching,and implementing the leader’s ‘vision’. We deploy Arendtian thinking to show how current models of school leadership enable totalitarian practices to become ordinary. Sixth, I develop Bourdieu’s concept of hysteresis through narratives from two heads to argue that rather than simply being an effect of change, hysteresis may be an actively sought outcome whereby the state intervenes to deprivilege welfarist headteachers and privilege corporatised principals through structurally facilitating their habitus and mandating its dispositions for the field. Collectively, these findings demonstrate how the diversification of provision in England and the demands of a performative, marketised regime have ontological and professional stakes for school leaders and for the led. Symbolic and economic capital is accruing to the capitalised, facilitated by corporate practices and corporate structural solutions through acquisitions and alliances. Resistance is possible, but a dissident habitus limits standing in the field. This hierarchisation is reflected in the relationship between school types and in how children are meant to self-select into that provision. This is a landscape constituted of positions, where pupils are expected to know their place and the purpose of education is to facilitate social segregation for economic efficiency.
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Radl, Viviane. "Influence of trenbolone on the structural and functional diversity of microbial communities from a lake sediment." [S.l.] : [s.n.], 2005. http://deposit.ddb.de/cgi-bin/dokserv?idn=978952626.
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Cairns, Amy J. "Structural Diversity in Crystal Chemistry: Rational Design Strategies Toward the Synthesis of Functional Metal-Organic Materials." Scholar Commons, 2010. http://scholarcommons.usf.edu/etd/3455.
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Metal-Organic Materials (MOMs) represent an important class of solid-state crystalline materials. Their countless attractive attributes make them uniquely suited to potentially resolve many present and future utilitarian societal challenges ranging from energy and the environment, all the way to include biology and medicine. Since the birth of coordination chemistry, the self-assembly of organic molecules with metal ions has produced a plethora of simple and complex architectures, many of which possess diverse pore and channel systems in a periodic array. In its infancy however this field was primarily fueled by burgeoning serendipitous discoveries, with no regard to a rational design approach to synthesis.
In the late 1980s, the field was transformed when the potential for design was introduced through the seminal studies conducted by Hoskins and Robson who transcended the pivotal works of Wells into the experimental regime. The construction of MOMs using metal-ligand directed assembly is often regarded as the origin of the molecular building block (MBB) approach, a rational design strategy that focuses on the self-assembly of pre-designed MBBs having desired shapes and geometries to generate structures with intended topologies by exploiting the diverse coordination modes and geometries afforded by metal ions and organic molecules.
The evolution of the MBB approach has witnessed tremendous breakthroughs in terms of scale and porosity by simply replacing single metal ions with more rigid inorganic metal clusters whilst preserving the inherent modularity and essential geometrical attributes needed to construct target networks for desired applications. The work presented in this dissertation focuses upon the rational design and synthesis of a diverse collection of open frameworks constructed from pre-fabricated rigid inorganic MBBs (i.e. [M(CO2)4], [M2(RCO2)4], [M3O(RCO2)6], MN3O3, etc), supermolecular building blocks (SBBs) and 3-, 4- and 6-connected organic MBBs. A systematic evaluation concerning the effect of various structural parameters (i.e. pore size and shape, metal ion, charge, etc) on hydrogen uptake and the relative binding affinity of H2-MOF interactions for selected systems is provided.
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Damaso, Natalie. "Biogeographical Patterns of Soil Microbial Communities: Ecological, Structural, and Functional Diversity and their Application to Soil Provenance." FIU Digital Commons, 2016. http://digitalcommons.fiu.edu/etd/3006.
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The current ecological hypothesis states that the soil type (e.g., chemical and physical properties) determines which microbes occupy a particular soil and provides the foundation for soil provenance studies. As human profiles are used to determine a match between evidence from a crime scene and a suspect, a soil microbial profile can be used to determine a match between soil found on the suspect’s shoes or clothing to the soil at a crime scene. However, for a robust tool to be applied in forensic application, an understanding of the uncertainty associated with any comparisons and the parameters that can significantly influence variability in profiles needs to be determined. This study attempted to address some of the most obvious uncertainties of soil provenance applications such as spatial variability, temporal variability, and marker selection (i.e., taxa discrimination). Pattern analysis was used to validate the ecological theories driving the soil microbial biogeography. Elucidating soil microbial communities’ spatial and temporal variability is critical to improve our understanding of the factors regulating their structure and function. Microbial profiling and bioinformatics analyses of the soil community provided a rapid method for soil provenance that can be informative, easier to perform, and more cost effective than approaches using traditional physico-chemical data. This study also showed that stable profiles may allow comparison between evidence and a possible crime scene despite the time lapse (4 years) between sample collections, however, this is dependent on the analysis method, site, vegetation, and level of disturbance. Marker selection was also an important consideration for profiling. Even though Fungi look promising for single taxon soil discrimination, the additional markers can help discriminate between a wide variety of soil types. As in human identification, the more DNA markers queried the greater the discrimination power. Lastly, this study illustrated a novel method to query the iron relating genes and ability to design a novel marker that can easily be used to profile the functional diversity of a soil community to enhance soil classification. Overall this research demonstrated the potential and effectiveness of using microbial DNA from soil, not just for comparison, but also for intelligence gathering to pinpoint the geographic origin of the soil.
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Andlauer, Till Felix Malte [Verfasser], and Stephan [Akademischer Betreuer] Sigrist. "Structural and Functional Diversity of Synapses in the Drosophila CNS / Till Felix Malte Andlauer. Betreuer: Stephan Sigrist." Würzburg : Universität Würzburg, 2013. http://d-nb.info/111208973X/34.
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Schönberger, Stefanie [Verfasser], and Konstantin [Akademischer Betreuer] Karaghiosoff. "Phosphorus, sulfur and pyridine : a unique combination to a great structural diversity / Stefanie Schönberger. Betreuer: Konstantin Karaghiosoff." München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2013. http://d-nb.info/1048522288/34.
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Andlauer, Till [Verfasser], and Stephan [Akademischer Betreuer] Sigrist. "Structural and Functional Diversity of Synapses in the Drosophila CNS / Till Felix Malte Andlauer. Betreuer: Stephan Sigrist." Würzburg : Universität Würzburg, 2013. http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-85018.
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Liao, Ge [Verfasser], and Shu-Ming [Akademischer Betreuer] Li. "Increasing structural diversity of natural products by enzymatic or nonenzymatic reactions / Ge Liao ; Betreuer: Shu-Ming Li." Marburg : Philipps-Universität Marburg, 2020. http://d-nb.info/1218685905/34.
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Smith, Kimberly J. "Understory Plant Responses to Uneven-Aged Forestry." ScholarWorks @ UVM, 2007. http://scholarworks.uvm.edu/graddis/216.
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In northern hardwood-conifer forests, alternatives to conventional forest management practices are being developed in order to maintain biodiversity and ecosystem functioning while providing for timber revenue generation. The understory layer of vegetation encompasses the majority of plant species diversity in forested ecosystems and may be sensitive to timber harvest disturbance. Thus, monitoring the response of forest understories to new silvicultural techniques may provide a means for evaluating their intensity. In this study, we hypothesize that i) uneven-aged, low-intensity silvicultural systems can maintain understory plant diversity and support latesuccessional species through harvest disturbance; ii) retaining and enhancing stand structural complexity can increase understory plant diversity in northern hardwoodconifer forests; and iii) plant responses are influenced by interactions between canopy structure, soils, and exogenous climate processes. Experimental treatments include two conventional uneven-aged prescriptions (single-tree selection and group selection) modified to increase structural retention, and a third technique designed to promote late-successional forest structure and function, termed structural complexity enhancement (SCE). Four replications of each treatment were applied to 2 ha management units at three sites in Vermont and New York, U.S.A. Understory vegetation was monitored over 2 years pre- and 4 years post-treatment. We used a linear mixed effects model to evaluate the effects of treatment, soil properties, and drought stress on understory diversity and abundance. Compositional changes among treatments were assessed with non-metric multidimensional scaling (NMS), an ordination technique. Model results show that over time, understory responses were strongly affected by overstory treatment and less influenced by soil chemistry and drought stress. All treatments were successful in maintaining overall composition and diversity. However, late-successional diversity increased significantly in SCE units compared to group selection units. These results indicate that while conventional uneven-aged systems are capable of maintaining understory plant diversity, variations that retain or enhance structural complexity may be more efficient at retaining latesuccessional species. Increased microsite heterogeneity as a result of these techniques may also increase understory plant diversity, at least during the initial post-harvest recovery period.
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Imsland, Freyja. "Monogenic Traits Associated with Structural Variants in Chicken and Horse : Allelic and Phenotypic Diversity of Visually Appealing Traits." Doctoral thesis, Uppsala universitet, Institutionen för medicinsk biokemi och mikrobiologi, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-259621.
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Domestic animals have rich phenotypic diversity that can be explored to advance our understanding of the relationship between molecular genetics and phenotypic variation. Since the advent of second generation sequencing, it has become easier to identify structural variants and associate them with phenotypic outcomes. This thesis details studies on three such variants associated with monogenic traits. The first studies on Rose-comb in the chicken were published over a century ago, seminally describing Mendelian inheritance and epistatic interaction in animals. Homozygosity for the otherwise dominant Rose-comb allele was later associated with reduced rooster fertility. We show that a 7.38 Mb inversion is causal for Rose-comb, and that two alleles exist for Rose-comb, R1 and R2. A novel genomic context for the gene MNR2 is causative for the comb phenotype, and the bisection of the gene CCDC108 is associated with fertility issues. The recombined R2 allele has intact CCDC108, and normal fertility. The dominant phenotype Greying with Age in horses was previously associated with an intronic duplication in STX17. By utilising second generation sequencing we have examined the genomic region surrounding the duplication in detail, and excluded all other discovered variants as causative for Grey. Dun is the ancestral coat colour of equids, where the individual is mostly pale in colour, but carries intensely pigmented primitive markings, most notably a dorsal stripe. Dun is a dominant trait, and yet most domestic horses are non-dun in colour and intensely pigmented. We show that Dun colour is established by radially asymmetric expression of the transcription factor TBX3 in hair follicles. This results in a microscopic spotting phenotype on the level of the individual hair, giving the impression of pigment dilution. Non-dun colour is caused by two different alleles, non-dun1 and non-dun2, both of which disrupt the TBX3-mediated regulation of pigmentation. Non-dun1 is associated with a SNP variant 5 kb downstream of TBX3, and non-dun2 with a 1.6 kb deletion that overlaps the non-dun1 SNP. Homozygotes for non-dun2 show a more intensely pigmented appearance than horses with one or two non-dun1 alleles. We have also shown by genotyping of ancient DNA that non-dun1 predates domestication.
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Robin, Adeline. "Structural diversity of Cu(I), Ag(I) and Cu(II) coordination polymers with the ligand ethanediyl bis(isonicotinate) /." Basel : [s.n.], 2005. http://edoc.unibas.ch/diss/DissB_7305.
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Förderer, Esther-Meena [Verfasser]. "Biogeography and Diversity Hotspots of Larger Indo-Pacific Foraminifera : A Structural Faunal Analysis from Raja Ampat / Esther-Meena Förderer." Bonn : Universitäts- und Landesbibliothek Bonn, 2018. http://d-nb.info/1190723301/34.
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Fredin, Sofia. "Class switching mechanism in antibodies : A conformational and structural investigation of the B-cell repertoire diversity of the CDR3." Thesis, Högskolan i Skövde, Institutionen för hälsovetenskaper, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:his:diva-19916.
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A process called class switching recombination (CSR) regulates the production of isotypes by enabling the switch of producing unspecific IgM or IgD to producing IgG, IgE, or IgA by causing an irreversible genomic rearrangement. Recent studies indicate a gap in the identification of the molecular mechanisms underlying CSR. This interdisciplinary project between bioinformatics and immunology aims to shed light onto these mechanisms and highlight differences in physicochemical properties in the B-cell repertoire to identify factors contributing to the decline in immune response with age and its relationships to CSR. The project is developed in line with the hypothesis that effective immune responses, and their resolution, require coordinated action from multiple different subclasses of antibodies. This is enabled by improvements in the high throughput sequencing techniques, which allows the B-cell repertoire to be revealed. The most variable portion of antibody molecules is the third complementarity determining region (CDR3) of the heavy chain. Hence, differences in hydrophobicity, pK value of the C-terminus peptide fragment, and the length of CDR3 were identified and accounted as factors that contribute to the decline in the immune response with age. Our understanding of how the immune response alters with age, is important for research applications in designing tailored vaccine strategies to ensure safety and efficacy. Development of in silico tools for the analysis of the B-cell repertoire is useful in extracting principles and functioning mechanisms that can be tested experimentally, helping in further characterizing CSR.
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Santos, Anita Stival dos. "Efeitos de filtros ambientais nos padrões de diversidade de árvores na floresta atlântica do sul do Brasil sob uma perspectiva de metacomunidades." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2014. http://hdl.handle.net/10183/106403.
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Entender padrões de diversidade e composição de espécies ao longo de múltiplas escalas espaciais constitui um dos principais objetivos em ecologia e biogeografia. A relativa importância dos mecanismos responsáveis por estruturar as comunidades de plantas e como eles interagem para influenciar estes padrões têm sido foco de intensos debates. No presente estudo, foram utilizados dados do Inventário Florístico Florestal de Santa Catarina a fim de investigar os padrões de diversidade de espécies de árvores e suas relações com a heterogeneidade ambiental sob uma das perspectivas oriundas da teoria de metacomunidades, conhecida como “sorteio de espécies”. A predição chave deste ponto de vista é a de que a composição de espécies varia em resposta a diferenças nas condições ambientais entre manchas de hábitat. O presente estudo é focado nessa predição e objetivou entender como processos relacionados a filtros ambientais interagem direta e indiretamente sobre os padrões de diversidade em uma área de 95000 km 2 (dados de 432 unidades amostrais). Foi utilizada modelagem de equações estruturais (PLS Path Modeling), a fim de investigar os efeitos interativos da topografia, clima, balanço de água e energia e geometria das manchas de floresta sobre os padrões de alfa (α) e beta (β) diversidade de uma metacomunidade de floresta atlântica no sul do Brasil. Fatores relacionados a filtros ambientais mostraram substanciais efeitos sobre a diversidade alfa e beta. A quantidade total da variação na beta diversidade explicada pela filtragem de hábitat foi alta (64%), corroborando a predição testada no nível de metacomunidades. Os fatores mais importantes para explicar a diversidade beta foram: extremos climáticos, balanço de água e energia e alfa diversidade, enquanto tamanho da mancha e balanço de água e energia foram os fatores chaves para a alfa diversidade. O teste de Mantel parcial mostrou que os efeitos ambientais ocorrem amplamente independente de efeitos espaciais, reforçando a predição testada. O estudo provê forte suporte empírico para a predição de que a beta diversidade reflete primariamente processos determinísticos associados com o nicho das espécies e suas respostas às condições ambientais na escala espacial considerada.Understanding patterns of species diversity and composition across multiple scales is one of the main purpose in ecology and biogeography. The relative importance of the mechanisms that structure plant communities and how they interact to influence these patterns remains a topic of hot debate. In the present study, we use data from the Forest Inventory of Santa Catarina to investigate the patterns of species diversity of subtropical Atlantic forests and its relationships with environmental heterogeneity on a metacommunity perspective (species-sorting). The key prediction of this viewpoint is that community composition varies in response to differences in environmental conditions among habitat patches. Our study focused on this perspective, aiming to understand how environmental filtering processes interact directly and indirectly on diversity patterns in an area of 95000 km 2 (data from 432 forest plots). We employed structural equation modeling (PLS Path Modeling) to disentangle the interactive effects of topography, climate, water-energy balance, and geometry of forest patches upon the alpha and beta diversity of a subtropical forest metacommunity in southern Brazil. Factors related to environmental filtering showed substantial effects upon tree alpha and beta diversity. The total amount of variation in beta diversity explained by environmental filtering was high (64%) and was even more when together with alpha diversity (73%), corroborating the prediction of species-sorting model at the metacommunity level. Climatic extremes, water-energy balance and alpha diversity were the key determinants of beta diversity and patch size and water- energy balance the key determinants of alpha diversity in the South Brazilian Atlantic forests. Partial mantel test showed that environmental effects occurred largely independent of spatial effects, reinforcing the tested prediction. Our study provides strong empirical support for the prediction that beta diversity primarily reflects deterministic factors associated with species niches and their responses to environmental conditions in the studied spatial scale.
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McElhinny, Chris, and chris mcelhinny@anu edu au. "Quantifying stand structural complexity in woodland and dry Sclerophyll Forest, South-Eastern Australia." The Australian National University. Centre for Resource and Environmental Studies, 2005. http://thesis.anu.edu.au./public/adt-ANU20060322.133914.
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In this thesis I present and test a methodology for developing a stand scale index of structural complexity. If properly designed such an index can act as a summary variable for a larger set of stand structural attributes, providing a means of ranking stands in terms of their structural complexity, and by association, their biodiversity and vegetation condition. This type of index can also facilitate the use of alternative policy instruments for biodiversity conservation, such as mitigation banking, auctions and offsets, that rely on a common currency the index value that can be compared or traded between sites. My intention was to establish a clear and documentable methodology for developing a stand scale index of structural complexity, and to test this methodology using data from real stands.¶
As a starting point, I reviewed the literature concerning forest and woodland structure and found there was no clear definition of stand structural complexity, or definitive suite of structural attributes for characterising it. To address this issue, I defined stand structural complexity as a combined measure of the number of different structural attributes present in a stand, and the relative abundance of each of these attributes. This was analogous to approaches that have quantified diversity in terms of the abundance and richness of elements. It was also concluded from the review, that stand structural complexity should be viewed as a relative, rather than absolute concept, because the potential levels of different structural attributes are bound within certain limits determined by the inherent characteristics of the site in question, and the biota of the particular community will have evolved to reflect this range of variation. This implied that vegetation communities with naturally simple structures should have the potential to achieve high scores on an index of structural complexity.¶
I proposed the following five-stage methodology for developing an index of stand structural complexity:
1. Establish a comprehensive suite of stand structural attributes as a starting point for developing the index, by reviewing studies in which there is an established relationship between elements of biodiversity and structural attributes.
2. Develop a measurement system for quantifying the different attributes included in the comprehensive suite.
3. Use this measurement system to collect data from a representative set of stands across the range of vegetation condition (highly modified to unmodified) and developmental stages (regrowth to oldgrowth) occurring in the vegetation communities in which the index is intended to operate.
4. Identify a core set of structural attributes from an analysis of these data.
5. Combine the core attributes in a simple additive index, in which attributes are scored relative to their observed levels in each vegetation community.¶
Stage one of this methodology was addressed by reviewing a representative sample of the literature concerning fauna habitat relationships in temperate Australian forests and woodlands. This review identified fifty-five studies in south-east and south-west Australia, in which the presence or abundance of different fauna were significantly (p<0.05) associated with vegetation structural attributes. The majority of these studies concerned bird, arboreal mammal, and ground mammal habitat requirements, with relatively fewer studies addressing the habitat requirements of reptiles, invertebrates, bats or amphibians. Thirty four key structural attributes were identified from these fifty-five studies, by grouping similar attributes, and then representing each group with a single generic attribute. This set, in combination with structural attributes identified in the earlier review, provided the basis for developing an operational set of stand level attributes for the collection of data from study sites.¶
To address stages two and three of the methodology, data were collected from one woodland community Yellow Box-Red Gum (E. melliodora-E. Blakelyi ) and two dry sclerophyll forest communities Broadleaved Peppermint-Brittle Gum (E. dives-E. mannifera ), Scribbly Gum-Red Stringybark (E. rossii E. macrorhyncha ) in a 15,000 km2 study area in the South eastern Highlands Bioregion of Australia. A representative set of 48 sites was established within this study area, by identifying 24 strata, on the basis of the three vegetation communities, two catchments, two levels of rainfall and two levels of condition, and then locating two sites (replicates) within each stratum. At each site, three plots were systematically established, to provide an unbiased estimate of stand level means for 75 different structural attributes.¶
I applied a three-stage analysis to identify a core set of attributes from these data. The first stage a preliminary analysis indicated that the 48 study sites represented a broad range of condition, and that the two dry sclerophyll communities could be treated as a single community, which was structurally distinct from the woodland community. In the second stage of the analysis, thirteen core attributes were dentified using the criteria that a core attribute should:¶
1. Be either, evenly or approximately normally distributed amongst study sites;
2. Distinguish between woodland and dry sclerophyll communities;
3. Function as a surrogate for other attributes;
4. Be efficient to measure in the field.
The core attributes were: Vegetation cover <0.5m Vegetation cover 0.5-6.0m; Perennial species richness; Lifeform richness; Stand basal area of live trees; Quadratic mean diameter of live stems; ln(number of regenerating stems per ha+1); ln(number of hollow bearing trees per ha+1);ln(number of dead trees per ha+1);sqrt(number of live stems per ha >40cm dbh); sqrt(total log length per ha); sqrt(total largelog length per ha); Litter dry weight per ha. This analysis also demonstrated that the thirteen core attributes could be modelled as continuous variables, and that these variables were indicative of the scale at which the different attributes operated.¶
In the third and final stage of the analysis, Principal Components Analysis was used to test for redundancy amongst the core attributes. Although this analysis highlighted six groupings, within which attributes were correlated to some degree, these relationships were not considered sufficiently robust to justify reducing the number of core attributes.¶
The thirteen core attributes were combined in a simple additive index, in which, each attribute accounted for 10 points in a total index value of 130. Attributes were rescaled as a score from 0-10, using equations that modelled attribute score as a function of the raw attribute data. This maintained a high correlation (r > 0.97, p< 0.0001) between attribute scores and the original attribute data. Sensitivity analysis indicated that the index was not sensitive to attribute weightings, and on this basis attributes carried equal weight. In this form my index was straightforward to apply, and approximately normally distributed amongst study sites.¶
I demonstrated the practical application of the index in a user-friendly spreadsheet, designed to allow landowners and managers to assess the condition of their vegetation, and to identify management options. This spreadsheet calculated an index score from field data, and then used this score to rank the site relative to a set of reference sites. This added a regional context to the operation of the index, and is a potentially useful tool for identifying sites of high conservation value, or for identifying sites where management actions have maintained vegetation quality. The spreadsheet also incorporated the option of calculating an index score using a subset of attributes, and provided a measure of the uncertainty associated with this score.¶
I compared the proposed index with five prominent indices used to quantify vegetation condition or habitat value in temperate Australian ecosystems. These were: Newsome and Catlings (1979) Habitat Complexity Score, Watson et al.s (2001) Habitat Complexity Score, the Site Condition Score component of the Habitat Hectares Index of Parkes et al. (2003), the Vegetation Condition Score component of the Biodiversity Benefits Index of Oliver and Parkes (2003), and the Vegetation Condition Score component of the BioMetric Assessment Tool of Gibbons et al. (2004). I found that my index differentiated between study sites better than each of these indices. However, resource and time constraints precluded the use of a new and independent data set for this testing, so that the superior performance of my index must be interpreted cautiously.¶
As a group, the five indices I tested contained attributes describing compositional diversity, coarse woody debris, regeneration, large trees and hollow trees these were attributes that I also identified as core ones. However, unlike these indices, I quantified weeds indirectly through their effect on indigenous plant diversity, I included the contribution of non-indigenous species to vegetation cover and did not apply a discount to this contribution, I limited the direct assessment of regeneration to long-lived overstorey species, I used stand basal area as a surrogate for canopy cover, I quantified litter in terms of biomass (dry weight) rather than cover, and I included the additional attributes of quadratic mean diameter and the number of dead trees.¶
I also concluded that Parkes et al. (2003), Oliver and Parkes (2003), and Gibbons et al. (2004), misapplied the concept of benchmarking, by characterising attributes in terms of a benchmark range or average level. This ignored processes that underpin variation at the stand level, such as the increased development of some attributes at particular successional stages, and the fact that attributes can respond differently to disturbance agents. It also produced indices that were not particularly sensitive to the differences in attribute levels occurring between stands. I suggested that a more appropriate application of benchmarking would be at the overarching level of stand structural complexity, using a metric such as the index developed in this thesis. These benchmarks could reflect observed levels of structural complexity in unmodified natural stands at different successional stages, or thresholds for structural complexity at which a wide range of biota are present, and would define useful goals for guiding on-ground management.
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Woojin, Kim. "THE EVOLVING DIVERSITY OF CORPORATE SYSTEMS: A COMPARATIVE STUDY ON THE TOYOTA GROUP AND THE HYUNDAI MOTOR GROUP." Kyoto University, 2015. http://hdl.handle.net/2433/202661.
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Yildirim, Håkan. "Structural diversity of the lipid A and core oligosaccharide moieties of the lipopolysaccharides from nontypeable and serotype f Haemophilus influenzae /." Stockholm, 2005. http://diss.kib.ki.se/2005/91-7140-504-6/.
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Lepitre, Thomas. "Modulation des Processus Domino au départ des Accepteurs de Michael en série Chromone : Diversité par aza-Cyclisation, Arylation et Aryloxylation Métallocatalysées : Diversité par aza-Cyclisation, Arylation et Aryloxylation Métallocatalysées." Thesis, Normandie, 2017. http://www.theses.fr/2017NORMLH31/document.
Full textAbstract:
Le concept de la DOS (Diversity-Oriented Synthesis) est une nouvelle approche qui vise à générer des collections de petites molécules avec des hauts degrés de diversité et de complexité structurale. Diverses stratégies ont été mises en place pour y parvenir de manière la plus efficace possible à partir de simples substrats de départ.Dans ce contexte, ce travail de thèse a permis de montrer comment un processus domino avait tout le potentiel à être exploité en tant que formidable outil dans le cadre d’une approche DOS, générateur à la fois de complexité mais également de diversité structurale. Un précurseur connu et largement étudié pour son caractère exceptionnellement versatile a été valorisé dans ce contexte : la 3-formylchromone. Dans ce manuscrit, nous montrerons comment il est possible de moduler le cours d’un processus domino pour atteindre de hauts degrés de diversité structurale, à partir des chromones accepteurs de Michael-1,6 et d’amines primaires. Nous verrons en particulier comment le contrôle d'une ou de plusieurs étapes clefs des séquences réactionnelles impliquées peut être réalisé selon :(I) la modulation pertinente d’une ou plusieurs unité(s) de structure au sein des substrats de départ, (II) la modulation des paramètres réactionnels (solvants, température, additifs), et(III) l’induction d’un changement de réactivité au sein d’un intermédiaire réactionnel par addition d’un agent externeIn the early 2000s a general consensus has emerged in which the molecular diversity within a given library of small molecules, rather than its size, has been recognized as a crucial requirement. Diversity-oriented synthesis (DOS) has emerged from this new paradigm. This novel approach aims to generate collections of small molecules with high degrees of structural diversity, in the most efficient way, starting from simple building-blocks. Since the generation of collections of structurally diverse small molecules in a DOS-driven approach constitutes a real challenge, diverse strategies have been set up for this purpose.In this line, this work has shed light on the great potential of a domino process as a valuable tool in a DOS-driven strategy, capable of generating both molecular diversity and architectural complexity. This study has been focused on the 3-formylchromone building block, a particular framework which has already proven being an exceptionally versatile precursor of molecular diversity. In this manuscript, we will highlight how it is possible to modulate the course of a domino process to achieve high degrees of molecular diversity, starting from the chromone based 1,6-Michael acceptors platform and primary amines as reaction partners. In particular we will show how it is feasible to control the course of particular steps involved in the domino process through: (I) the pertinent modulation of the Michael acceptors and the primary amines structures, (II) the modulation of the reaction parameters (solvent, temperature, additives), and (III) the tuning of the reactivity within a key reaction intermediate induced by the introduction of an external agent
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Rafati, Nima. "Exploring genetic diversity in natural and domestic populations through next generation sequencing." Doctoral thesis, Uppsala universitet, Institutionen för medicinsk biokemi och mikrobiologi, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-315032.
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Studying genetic diversity in natural and domestic populations is of major importance in evolutionary biology. The recent advent of next generation sequencing (NGS) technologies has dramatically changed the scope of these studies, enabling researchers to study genetic diversity in a whole-genome context. This thesis details examples of studies using NGS data to: (i) characterize evolutionary forces shaping the genome of the Atlantic herring, (ii) detect the genetic basis of speciation and domestication in the rabbit, and, (iii) identify mutations associated with skeletal atavism in Shetland ponies. The Atlantic herring (Clupea harengus) is the most abundant teleost species inhabiting the North Atlantic. Herring has seasonal reproduction and is adapted to a wide range of salinity (3-35‰) throughout the Baltic Sea and Atlantic Ocean. By using NGS data and whole-genome screening of 20 populations, we revealed the underlying genetic architecture for both adaptive features. Our results demonstrated that differentiated genomic regions have evolved by natural selection and genetic drift has played a subordinate role. The European rabbit (Oryctolagus cuniculus) is native to the Iberian Peninsula, where two rabbit subspecies with partial reproductive isolation have evolved. We performed whole genome sequencing to characterize regions of reduced introgression. Our results suggest key role of gene regulation in triggering genetic incompatibilities in the early stages of reproductive isolation. Moreover, we studied gene expression in testis and found misregulation of many genes in backcross progenies that often show impaired male fertility. We also scanned whole genome of wild and domestic populations and identified differentiated regions that were enriched for non-coding conserved elements. Our results indicated that selection has acted on standing genetic variation, particularly targeting genes expressed in the central nervous system. This finding is consistent with the tame behavior present in domestic rabbits, which allows them to survive and reproduce under the stressful non-natural rearing conditions provided by humans. In Shetland ponies, abnormally developed ulnae and fibulae characterize a skeletal deformity known as skeletal atavism. To explore the genetic basis of this disease, we scanned the genome using whole genome resequencing data. We identified two partially overlapping large deletions in the pseudoautosomal region (PAR) of the sex chromosomes that remove the entire coding sequence of the SHOX gene and part of CRLF2 gene. Based on this finding, we developed a diagnostic test that can be used as a tool to eradicate this inherited disease in horses.