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Dissertationen zum Thema „Functional expansion“
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1
Ugolotti, Alessandro. „Alternative derivative expansion in Functional RG and application“. Master's thesis, Alma Mater Studiorum - Università di Bologna, 2016. http://amslaurea.unibo.it/10434/.
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We give a brief review of the Functional Renormalization method in quantum field theory, which is intrinsically non perturbative, in terms of both the Polchinski equation for the Wilsonian action and the Wetterich equation for the generator of the proper verteces.
For the latter case we show a simple application for a theory with one real scalar field within the LPA and LPA' approximations.
For the first case, instead, we give a covariant "Hamiltonian" version of the Polchinski equation which consists in doing a Legendre transform of the flow for the corresponding effective Lagrangian replacing arbitrary high order derivative of fields with momenta fields. This approach is suitable for studying new truncations in the derivative expansion.
We apply this formulation for a theory with one real scalar field and, as a novel result, derive the flow equations for a theory with N real scalar fields with the O(N) internal symmetry. Within this new approach we analyze numerically the scaling solutions for N=1 in d=3 (critical Ising model), at the leading order in the derivative expansion with an infinite number of couplings, encoded in two functions V(phi) and Z(phi), obtaining an estimate for the quantum anomalous dimension with a 10% accuracy (confronting with Monte Carlo results).
2
Glasbrenner, David C. Jr. „Evolution, Expansion, and Functional Divergence of the Commissureless Protein Family“. The Ohio State University, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=osu1557143164958451.
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Han, Zhuoran S. M. Massachusetts Institute of Technology. „Performance analysis of functional expansion tallies on 2D PWR pin cell“. Thesis, Massachusetts Institute of Technology, 2020. https://hdl.handle.net/1721.1/129907.
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Thesis: S.M., Massachusetts Institute of Technology, Department of Nuclear Science and Engineering, February, 2020Cataloged from student-submitted PDF of thesis.
Includes bibliographical references (pages 85-87).
Functional Expansion Tally (FET) method has been rigorously studied in recent years, as it has the potential to model spatial distributions of physics parameters in coupled multiphysics simulations with better computing performance. Although the FETs have been implemented in some nuclear applications, the performance of FETs using a Zernike polynomial series has never been thoroughly tested. This work performs an analysis of Zernike-based FETs on a 2D PWR pin-cell geometry and compares the simulation time and accuracy with conventional histogram tallies for reaction rate tallies needed in burnup calculations over radial rings. Figures of Merit (FOMs) are constructed for direct comparison of performance between different tally schemes and several metrics are used to determine the optimal expansion order. It is determined that Zernike-based FETs achieve comparable performance to discrete tallies, but require very high radial orders to properly capture the spatial distribution of certain reaction rates, such as U-238 absorption. A generalized functional expansion method using an arbitrary series of independent functions as basis set is then proposed and tested. To capture the self-shielding effect of the U-238 absorption rate, an exponential basis set is chosen. The results show that the exponential basis set can reduce the optimum order of expansion by half comparing with orthogonal Zernike polynomials while achieving the same accuracy. The integrated reaction rate is also demonstrated to be preserved. This work also shows that the generalized functional expansion could be a heuristic method for further investigation of continuous depletion problems.
by Zhuoran Han.
S.M.
S.M. Massachusetts Institute of Technology, Department of Nuclear Science and Engineering
4
Nelson, Lance Jacob. „Cluster Expansion Models Via Bayesian Compressive Sensing“. BYU ScholarsArchive, 2013. https://scholarsarchive.byu.edu/etd/4032.
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The steady march of new technology depends crucially on our ability to discover and design new, advanced materials. Partially due to increases in computing power, computational methods are now having an increased role in this discovery process. Advances in this area speed the discovery and development of advanced materials by guiding experimental work down fruitful paths. Density functional theory (DFT)has proven to be a highly accurate tool for computing material properties. However, due to its computational cost and complexity, DFT is unsuited to performing exhaustive searches over many candidate materials or for extracting thermodynamic information. To perform these types of searches requires that we construct a fast, yet accurate model. One model commonly used in materials science is the cluster expansion, which can compute the energy, or another relevant physical property, of millions of derivative superstructures quickly and accurately. This model has been used in materials research for many years with great success. Currently the construction of a cluster expansion model presents several noteworthy challenges. While these challenges have obviously not prevented the method from being useful, addressing them will result in a big payoff in speed and accuracy. Two of the most glaring challenges encountered when constructing a cluster expansion model include:(i) determining which of the infinite number of clusters to include in the expansion, and (ii) deciding which atomic configurations to use for training data. Compressive sensing, a recently-developed technique in the signal processing community, is uniquely suited to address both of these challenges. Compressive sensing (CS) allows essentially all possible basis (cluster) functions to be included in the analysis and offers a specific recipe for choosing atomic configurations to be used for training data. We show that cluster expansion models constructed using CS predict more accurately than current state-of-the art methods, require little user intervention during the construction process, and are orders-of-magnitude faster than current methods. A Bayesian implementation of CS is found to be even faster than the typical constrained optimization approach, is free of any user-optimized parameters, and naturally produces error bars on the predictions made. The speed and hands-off nature of Bayesian compressive sensing (BCS) makes it a valuable tool for automatically constructing models for many different materials. Combining BCS with high-throughput data sets of binary alloy data, we automatically construct CE models for all binary alloy systems. This work represents a major stride in materials science and advanced materials development.
5
Essomba, Rene Franck. „An investigation into Functional Linear Regression Modeling“. Master's thesis, University of Cape Town, 2015. http://hdl.handle.net/11427/15591.
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Functional data analysis, commonly known as FDA", refers to the analysis of information on curves of functions. Key aspects of FDA include the choice of smoothing techniques, data reduction, model evaluation, functional linear modeling and forecasting methods. FDA is applicable in numerous applications such as Bioscience, Geology, Psychology, Sports Science, Econometrics, Meteorology, etc. This dissertation main objective is to focus more specifically on Functional Linear Regression Modelling (FLRM), which is an extension of Multivariate Linear Regression Modeling. The problem of constructing a Functional Linear Regression modelling with functional predictors and functional response variable is considered in great details. Discretely observed data for each variable involved in the modelling are expressed as smooth functions using: Fourier Basis, B-Splines Basis and Gaussian Basis. The Functional Linear Regression Model is estimated by the Least Square method, Maximum Likelihood method and more thoroughly by Penalized Maximum Likelihood method. A central issue when modelling Functional Regression models is the choice of a suitable model criterion as well as the number of basis functions and an appropriate smoothing parameter. Four different types of model criteria are reviewed: the Generalized Cross-Validation, the Generalized Information Criterion, the modified Akaike Information Criterion and Generalized Bayesian Information Criterion. Each of these aforementioned methods are applied to a dataset and contrasted based on their respective results.
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Marinello, Martina. „Ataxin-7 SUMOylation and its functional consequences in the spinocerebellar ataxia type 7 (SCA7) pathophysiology“. Thesis, Paris 6, 2014. http://www.theses.fr/2014PA066266/document.
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L'ataxie spinocérébelleuse de type 7 (SCA7) est une maladie neurodégénerative due à une expansion de CAG traduit en polyQ dans la protéine ataxine-7. La SUMOylation, modification post-traductionnelle que nous avons identifiée moduler l'agrégation de la protéine mutante, est facilitée par une SUMO E3 ligase.Nous avons identifié RanBP2, une nucléoporine appartenant au complexe du pore nucléaire en tant que SUMO E3 ligase, via SUMO-1 de l'ataxine-7. En effet, le silencing de RanBP2 induit l'agrégation de l'ataxine-7 mutante, ce qui démontre l'implication de RanBP2 dans la physiopathologie de SCA7. Nous montrons également que l'ataxine-7 endogène est une cible modifiée par SUMO-1 et -2. L'ataxine-7 poly-SUMOylée, grâce à la présence de chaines SUMO2/3, est capable de recruter RNF4. Cette protéine conduit à la dégradation de l'ataxine-7 mutante par la voie du protéasome. La dégradation est abolie en présence d'un mutant de RNF4.Dans un modèle murin KI SCA7, nous avons quantifié l'expression des gènes impliqués dans la voie de la SUMOylation au niveau des régions les plus touchées du cerveau. Le niveau d'expression des ARNs messagers montre des altérations dépendantes des répétitions CAG du gène SCA7. A 6 mois (avant le début de la pathologie), les premières dérégulations sont observées; à 12 mois (à un stade avancé de la maladie), on note une diminution statistiquement significative de Sumo-1 dans le cervelet des souris Atxn7100Q/5Q. Ces résultats, alliés à l'observation de l'accumulation anormale des protéines SUMO-1 et RanBP2 dans le cervelet d'un patient SCA7, suggèrent que les voies de la SUMOylation in vivo peuvent être perturbées dans SCA7Spinocerebellar ataxia type 7 (SCA7) is a neurodegenerative disease caused by a CAG expansion (polyQ) in the protein ataxin-7. SUMOylation, a post-translational modification that we identified to modulate mutant protein aggregation in a SCA7 cellular model, is facilitated by a SUMO E3 ligase. Here, we identified RanBP2 (Nup358), a nucleoporin belonging to the nuclear pore complex, as the major E3 enzyme implicated in ataxin-7 modification by SUMO-1. Indeed, RanBP2 silencing renders mutant ataxin-7 more prone to aggregation, thus demonstrating the implication of RanBP2 in SCA7 pathophysiology. We also show that endogenous ataxin-7 is a target for both SUMO-1 and -2 modification. Poly-SUMOylated ataxin-7 presents a docking site composed of SUMO2/3 chains for the recruitment of RNF4: this protein is a SUMO E3 ubiquitin ligase that mediates degradation of mutant ataxin-7 by the proteasome pathway. The degradation is abolished in presence of a mutant form of RNF4. In a SCA7 knock-in mouse model we quantified expression of SUMO-pathway related genes in cerebellum and retina, the most affected regions using quantitative RT-PCR. SUMO-related genes show expanded repeat-dependent alterations in expression patterns. At 6 months (before onset), deregulations begin to occur; by 12 months (late stage of disease), there is a statistically significant impairment in Sumo-1 levels in Atxn7100Q/5Q cerebellum. These results, together with the observation that SUMO-1 and RanBP2 protein accumulate abnormally in the cerebellum of a SCA7 patient, suggest that in vivo SUMO-modifying pathways may be perturbed in SCA7
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Karch, Matthias Ottmar. „Design and Manufacturing of Hierarchical Multi-Functional Materials Via High Resolution additive Manufacturing“. Master's thesis, Virginia Tech, 2017. http://tuprints.ulb.tu-darmstadt.de/6788/1/Master_Thesis_Karch_Matthias_Ottmar.pdf.
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Musser, Jason. „Higher Derivatives of the Hurwitz Zeta Function“. TopSCHOLAR®, 2011. http://digitalcommons.wku.edu/theses/1093.
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The Riemann zeta function ζ(s) is one of the most fundamental functions in number theory. Euler demonstrated that ζ(s) is closely connected to the prime numbers and Riemann gave proofs of the basic analytic properties of the zeta function. Values of the zeta function and its derivatives have been studied by several mathematicians. Apostol in particular gave a computable formula for the values of the derivatives of ζ(s) at s = 0. The Hurwitz zeta function ζ(s,q) is a generalization of ζ(s). We modify Apostolʼs methods to find values of the derivatives of ζ(s,q) with respect to s at s = 0. As a consequence, we obtain relations among certain important constants, the generalized Stieltjes constants. We also give numerical estimates of several values of the derivatives of ζ(s,q).
9
Bhattacharyya, Anirban. „Application of effective field theory to density functional theory for finite systems“. Connect to resource, 2005. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1124116299.
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Thesis (Ph. D.)--Ohio State University, 2005.Title from first page of PDF file. Document formatted into pages; contains xv, 210 p.; also includes graphics (some col.). Includes bibliographical references (p. 205-210). Available online via OhioLINK's ETD Center
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Motta, Cecilia Margarida Mendes. „Effect of surface functional groups on chondrocyte behavior using molecular gradients“. University of Akron / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=akron1460392374.
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11
Pueschel, Charles A. „First principles approach to understanding stability and phase transitions of metal A(II)B(IV)hexafluorides“. Thesis, Georgia Institute of Technology, 2015. http://hdl.handle.net/1853/54484.
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Ramirez, Carole Women's & Children's Health Faculty of Medicine UNSW. „Phenotypic and functional changes in cord blood stem cell progeny after cytokine activation“. Awarded by:University of New South Wales, 2007. http://handle.unsw.edu.au/1959.4/39798.
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Human umbilical cord blood, an alternate source of haematopoietic stem cells (HSC), has been successfully used to reconstitute haematopoiesis in both related and unrelated transplant recipients. However, because CB has fewer total cells (and as a consequence fewer HSC and progenitor cells) CB transplant recipients often experience delayed engraftment as compared with that seen in bone marrow or mobilized peripheral blood transplant recipients. Delayed engraftment exposes patients to an increased risk of infection and bleeding. Cytokine-mediated expansion has been investigated to improve engraftment after CB HSC transplantation as a means to expand the total cell number and both the HSC and progenitors populations. However, its effect on HSC function remains controversial. We hypothesise that if cytokine-mediated expansion promotes divisional recruitment and multilineage differentiation it causes changes in phenotype and cell cycle related gene expression which may be detrimental to the engraftment capacity of haematopoietic cells. Therefore we investigated the relationship between cell division, phenotype and engraftment potential of CB CD34+ cells following cytokine-mediated expansion. High resolution cell division tracking using the fluorescent dye CFSE was used to monitor changes as a consequence of cytokine-mediated expansion in phenotype and function in CB CD34+ cells. Cytokine-mediated expansion caused upregulation of lineage and proliferation markers and adhesion molecules and downregulation of putative stem cell markers with concomitant cell division. However, these changes in phenotype as a consequence of cytokine-mediated expansion may not reflect or be predictive of a functional change in the expanded population. Cytokine-mediated expansion of CB CD34+ also caused changes in cell cycle related gene expression of G1 phase regulators. CB CD34+ cells exhibited expression of all D cyclins, albeit at different levels and p21WAF1 was differentially expressed across CB samples. The effect of cell division on the engraftment potential as a consequence of cytokine-mediated expansion was examined in CB CD34+. Cytokine-mediated expansion of CB CD34+ cells reduced, but did not completely eliminate engraftment potential, as a proportion of the expanded and divided cell populations retained their ability to engraft the NOD-SCID mouse. Overall, this study confirms reports in the literature that cytokine-mediated expansion induces changes in the phenotype of HSC and compromises their in vivo function.
13
Correia, Fagner Cintra [UNESP]. „The standard model effective field theory: integrating UV models via functional methods“. Universidade Estadual Paulista (UNESP), 2017. http://hdl.handle.net/11449/151703.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
O Modelo Padrão Efetivo é apresentado como um método consistente de parametrizar Física Nova. Os conceitos de Matching e Power Counting são tratados, assim como a Expansão em Derivadas Covariantes introduzida como alternativa à construção do conjunto de operadores efetivos resultante de um modelo UV particular. A técnica de integração funcional é aplicada em casos que incluem o MP com Tripleto de Escalares e diferentes setores do modelo 3-3-1 na presença de Leptons pesados. Finalmente, o coeficiente de Wilson de dimensão-6 gerado a partir da integração de um quark-J pesado é limitado pelos valores recentes do parâmetro obliquo Y.
It will be presented the principles behind the use of the Standard Model Effective Field Theory as a consistent method to parametrize New Physics. The concepts of Matching and Power Counting are covered and a Covariant Derivative Expansion introduced to the construction of the operators set coming from the particular integrated UV model. The technique is applied in examples including the SM with a new Scalar Triplet and for different sectors of the 3-3-1 model in the presence of Heavy Leptons. Finally, the Wilson coefficient for a dimension-6 operator generated from the integration of a heavy J-quark is then compared with the measurements of the oblique Y parameter.
CNPq: 142492/2013-2
CAPES: 88881.132498/2016-01
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Correia, Fagner Cintra. „The standard model effective field theory : integrating UV models via functional methods /“. São Paulo, 2017. http://hdl.handle.net/11449/151703.
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Orientador: Vicente PleitezResumo: O Modelo Padrão Efetivo é apresentado como um método consistente de parametrizar FísicaNova. Os conceitos de Matching e Power Counting são tratados, assim como a Expansão emDerivadas Covariantes introduzida como alternativa à construção do conjunto de operadoresefetivos resultante de um modelo UV particular. A técnica de integração funcional é aplicadaem casos que incluem o MP com Tripleto de Escalares e diferentes setores do modelo 3-3-1 napresença de Leptons pesados. Finalmente, o coeficiente de Wilson de dimensão-6 gerado a partirda integração de um quark-J pesado é limitado pelos valores recentes do parâmetro obliquo Y.
Doutor
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Zhang, Yan. „In vitro Functional Properties and In vivo Local Effects of Transplanted Human Progenitor Cells in Ischemic Tissues“. Thèse, Université d'Ottawa / University of Ottawa, 2011. http://hdl.handle.net/10393/20216.
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Growing evidence from animal and clinical studies suggests that cardiac cell therapy can restore perfusion and improve function in the ischemic/infarcted myocardium. However, cell therapy is hindered by insufficient cell numbers, inefficient cell homing and engraftment, and inadequate cellular interactions. Furthermore, the biological mechanisms and local effects of transplanted cells have not been well-elucidated. The research presented herein attempts to address some of these issues.
In manuscript #1, a new subpopulation of circulating progenitor cells (CPCs), termed derived CD133+ cells, was generated from the CD133- fraction of human peripheral blood. The derived CD133+ progenitors appeared to have superior vasculogenic potential in vitro, which may prove to be beneficial in inducing vasculogenesis in ischemic tissues.
Positron emission tomography (PET) with direct cell labeling and reporter gene techniques were employed to assess the fate of transplanted human CPCs in vivo at different subjects of investigation, and different stages of cell transplantation. In manuscript #2, PET imaging with 2-[18F]fluoro-2-deoxy-D-glucose (18F-FDG) direct cell labeling was used to demonstrate that collagen-based matrices improve the early homing and retention of delivered CPCs in a rat ischemic hindlimb model. This mechanism conferred by the matrix may have implications on cell therapy at the early stages after transplantation.
In manuscript #3, a more efficient, stable and accurate labeling method, hexadecyl-4-[18F]fluorobenzoate (18F-HFB) direct cell labeling, was developed to quantify cell distribution of transplanted CPCs in a rat myocardial infarction model. PET imaging of 18F-HFB-CPCs revealed significant cell washout from the myocardium immediately after intramyocardial injection, with only a small proportion of transplanted CPCs remaining in the target area in the first 4 hours after delivery.
In manuscript #4, human CPCs transduced with lentiviral vectors showed stable expression of PET reporter genes. This reporter gene based-cell labeling technique can be developed for noninvasive tracking cells within a bioengineered matrix by PET, while preserving cell phenotype, viability and function.
These studies contribute important insights into the biology and physiology of transplanted stem cells and the ability of delivery matrices to improve transplanted cell engraftment, survival, and function. I believe with further refinement, cell expansion, tissue engineering and PET imaging could facilitate the clinical applications of cell therapies in years to come.
16
Dumont, Alain. „Insights into the dynamics of T cell clonal expansion and the functional heterogeneity of memory CD4 T lymphocytes using superantigens“. Thesis, McGill University, 2004. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=84235.
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Superantigens trigger the polyclonal activation of human T cells. We exploited this property to gain insight into the mechanisms governing CD4 T cell expansion and to study the functional heterogeneity of naive and memory CD4 T cell subsets. We show that the amount of TCR ligand affects the evolution of a T cell response in two ways: by shaping the diversity of the T cell population recruited in the proliferative pool and by affecting the progression of these precursors into cell cycle. These two processes characterize a hierarchy of recruitment of cells that strongly correlates with the efficiency of TCR engagement but not with the relative precursor frequency in the non-immune repertoire. Remarkably, once established, the distribution of T cell clones within a selected repertoire is maintained by the characteristic of T cells to expand at a rate that is independent of quantitative differences in ligand exposure. Moreover, at optimal ligand concentrations that lead to the simultaneous expansion of all responsive T cell clones, we observed a marked clone-specific heterogeneity in the capacity to secrete cytokines. The functional heterogeneity of different CD4+ T cell subpopulations was also studied using a superantigen model. Based on the expression of CD45RA and CCR7, four distinct subsets of CD4+ T lymphocytes can be identified: naive (CD45RA+ CCR7+), central memory (TCM, CD45RA- CCR7+), effector memory (TEM, CD45RA- CCR7-) and a previously uncharacterized subset (CD45RA+ CCR7-). In CD8 T cells, this subset has been shown to comprise "terminally differentiated" effector memory cells. The four subsets show different functional sensitivities for the superantigens, the TEM population being the most sensitive and the naive cells being the least sensitive, as measured by the upregulation of activation markers. We show that the CD4+ CD45RA+CCR7- subpopulation, which is rarely detectable in healthy individuals, is enriched in T cells having str
17
Yagi, Takanobu. „Variations in Current-year Shoot Properties in Cool-temperate Tree Species in Japan : Functional Differentiation for Foliage-maintenance and Crown-expansion“. Kyoto University, 2000. http://hdl.handle.net/2433/151582.
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Kyoto University (京都大学)0048
新制・課程博士
博士(農学)
甲第8526号
農博第1135号
新制||農||806(附属図書館)
学位論文||H12||N3429(農学部図書室)
UT51-2000-J35
京都大学大学院農学研究科林学専攻
(主査)教授 武田 博清, 教授 菊沢 喜八郎, 教授 大畠 誠一
学位規則第4条第1項該当
18
Wang, Kaihang. „Orthogonal ribosome evolution : 1. Functional epitopes at the ribosome subunit interface; 2. Evolved orthogonal ribosomes enhance the efficiency of synthetic genetic code expansion“. Thesis, University of Cambridge, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.612470.
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Yang, Qigui. „Theoretical study of Gd2O3-CeO2 (111) interface“. Thesis, KTH, Materialvetenskap, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-234848.
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Atomistic modelling has widely been applied for studying structures and properties of materials. There are various methods to perform atomistic modelling. This master thesis presents a combined density functional theory (DFT) and cluster expansion (CE) study of Gd2O3 and Gd2O3-CeO2 interface (GCI) relevant for solid oxide fuel cells (SOFCs). The energy differences (ΔE) of Va-O exchanges in C-type Gd2O3 and at GCI are calculated using both DFT and CE methods. We also calculated the migration energy (Emig) of Va jumps in Gd2O3 and at GCI by DFT. The comparison between the CE and DFT results demonstrates that the CE method provides a relatively accurate estimation of ΔE while it requires less computational resources. Furthermore, the CE method is used to study the Va migration in the vicinity of the Gd2O3-CeO2 interface. The potential energy landscapes of different types of paths are studied.Atomistisk modellering har i stor utsträckning använts för att studera strukturer och egenskaper hos material. Det finns många olika metoder för att utföra atomistisk modellering. Detta masterprojekt presenterar en kombinerad density functional theory (DFT) och cluster expansion (CE) studie av Gd2O3- och Gd2O3-CeO2 gränssnittet (GCI), relevant för fastoxidbränsleceller (SOFC). Energiskillnaderna (ΔE) för Va-O-utbytet i C-typ Gd2O3 och vid GCI beräknas med användning av både DFT- och CE-metoder. Vi beräknade också migrationsenergin (Emig) av Va-hopp i Gd2O3 och vid GCI med DFT. Jämförelsen mellan CE och DFT-resultaten visar att CE-metoden ger en relativt noggrann uppskattning av ΔE samt att den kräver mindre beräkningsresurser. Vidare används CE-metoden för att studera Va- migrering i närheten av Gd2O3-CeO2-gränssnittet. Det potentiella energilandskapet för olika vägar studeras.
20
Arantes, Carolina de Silvério. „O processo de nucleação em ambiente savânico do cerrado“. Universidade Federal de Uberlândia, 2016. https://repositorio.ufu.br/handle/123456789/13286.
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Fundação de Amparo a Pesquisa do Estado de Minas GeraisNucleation process occurs naturally at savannic areas as of the changes promoted by scattered trees that facilitate the colonization of crown area by new individuals and species, including species typical of forest environment. This process can be influenced by several factors such as the physical characteristics of the nuclei, the species of nucleus and the response of nuclei and colonizers to fire. The aim of this study was to describe the nucleation process in savannic environment of Cerrado, from: the description of the environmental changes promoted by nuclei at crown area and the influence of these changes, as well as the physical parameters (crown area and distance from forest formation) of nuclei, in the structure and composition of the community colonizing nuclei (Chapter 1); the analysis of the influence of fire on the structure, composition, functional diversity and resilience of the community colonizing nuclei (Chapter 2); and the description of the influence of the difference in the species of nucleator in the structure, composition, functional diversity and response to fire of communities colonizing the three species of nuclei. Scattered trees at savannic environments of Cerrado act as nucleating, favoring the crown area colonization by a denser and more diverse community, especially by those species typical of forest environment. The fire alters the structure and composition of the community colonizing the nuclei, which has become less dense and more diverse than the community colonizing this environment before the fire, as well as increasing functional diversity based on richness and the occurrence of resprount among individuals colonizing the community after the fire. The larger the capacity of the nucleator, regardless of species, of generating greater shading, higher humidity and higher nutrient availability, denser and more diverse the community colonizing the nuclei will be.
A nucleação ocorre de forma natural nas áreas savânicas a partir das modificações promovidas pelos indivíduos arbóreos que facilitam a colonização do ambiente abaixo da copa por novos indivíduos e espécies, incluindo espécies típicas de ambiente florestal. Este processo pode ser influenciado por vários fatores como, as características físicas do indivíduo nucleador, a espécie nucleadora e a resposta dos indivíduos nucleadores e colonizadores ao fogo. O objetivo deste estudo foi descrever o processo de nucleação em ambiente savânico do Cerrado, a partir da: descrição das modificações ambientais promovidas pelos indivíduos nucleadores na área da copa e a influência destas modificações, bem como dos parâmetros físicos dos núcleos (área da copa e distância até a formação florestal), na estrutura e composição da comunidade colonizadora dos núcleos (Capítulo 1); análise da influência do fogo na estrutura, composição, diversidade funcional e resiliência da comunidade colonizadora dos núcleos (Capítulo 2); e descrição da influência da diferença das espécies nucleadoras na estrutura, composição, diversidade funcional e resposta ao fogo das comunidades colonizadoras das três espécies nucleadoras. Os indivíduos arbóreos do cerrado sentido restrito atuam como nucleadores favorecendo a colonização da área da copa por uma maior densidade e diversidade de espécies, especialmente aquelas típicas de ambiente florestal. A ocorrência de fogo altera a estrutura e composição desta comunidade colonizadora dos núcleos, que se apresenta menos densa e com maior riqueza que a comunidade colonizadora deste ambiente antes do fogo, além de aumentando a diversidade funcional baseada na riqueza e a ocorrência de rebrota entre os indivíduos que compõem a comunidade após o fogo. Quanto maior for a capacidade do indivíduo nucleador, independente da espécie, de gerar maior sombreamento, maior umidade e maior disponibilidade de nutrientes, mais densa e mais diversa será a comunidade colonizadora deste núcleo.
Doutor em Ecologia e Conservação de Recursos Naturais
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Götz, Andreas W. [Verfasser], und Andreas [Akademischer Betreuer] Görling. „The Limited Expansion of Diatomic Overlap Density Functional Theory (LEDO-DFT): Development and Implementation of Algorithms, Optimization of Auxiliary Orbitals and Benchmark Calculations / Andreas Walter Götz. Betreuer: Andreas Görling“. Erlangen : Universitätsbibliothek der Universität Erlangen-Nürnberg, 2005. http://d-nb.info/1035574977/34.
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Gilain, Agathe. „Economic evaluation of designing in the unknown : Design theory-based models beyond decision theory under uncertainty“. Electronic Thesis or Diss., Université Paris sciences et lettres, 2021. http://www.theses.fr/2021UPSLM025.
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La théorie de la décision offre des techniques de calcul qui quantifient la valeur de l'information dans l’incertain et permettent de guider des décisions en conséquence. Ces techniques sont très pertinentes pour le calcul économique dans l'incertain. En revanche, elles négligent la valeur de l'inconnu. Et il est largement prouvé que de telles techniques sont inappropriées, voire induisent en erreur dans des situations qui contiennent de l'inconnu. Cela signifie-t-il que dans l'inconnu, les calculateurs économiques devraient renoncer à toute forme d'approche calculatoire, et guider leurs décisions en s’appuyant sur leurs intuitions? Ou pourrions-nous envisager une approche de calcul qui isolerait et évaluerait les effets économiques dans l'inconnu ? Ce travail de recherche offre quelques réponses à ces questions, en étudiant des phénomènes économiques observés dans le secteur de l'aviation commerciale, où le calcul économique est massivement utilité (études de rentabilité, analyse des coûts...), et en mobilisant la théorie de la conception qui rend compte de l'émergence de l'inconnu. Un premier axe de recherche concerne les impacts de l'inconnu en conception réglée : nous cherchons à identifier la mesure dans laquelle l'inconnu peut impacter les coûts de développement d'un produit, en simulant la relation entre expansion fonctionnelle et dynamique d'augmentation des coûts de développement avec le temps. Nos simulations révèlent que l'expansion fonctionnelle génère de véritables chocs dans l'architecture d'un produit, dont l'impact sur les coûts peut être considérable. Et nous étudions comment des techniques classiques de réduction des coûts (modularisation, sur-investissement dans de l’apprentissage anticipé) pourraient réduire les coûts de l'expansion fonctionnelle. Cela amène à discuter comment une utilisation à mauvais escient de techniques classiques de réduction des coûts en situation d'expansion fonctionnelle peuvent générer des catastrophes industrielles. Un deuxième axe s'intéresse à des situations d'investissement dont les rendements économiques semblent incompréhensibles dans le cadre de la théorie de la décision. Nous démontrons que l'inconnu a joué un rôle dans la génération de ces rendements. Et nous montrons que des raisonnements, méthodes et des principes managériaux relevant de la conception innovante ont été utilisés pour explorer rigoureusement l'inconnu et générer de tels rendements. Les résultats de ce travail suggèrent que l'inconnu peut être géré comme une variable économique à part entière, ce qui soulève d'autres questions, notamment au sujet des types d'organisation qui pourraient déployer du 'calcul économique dans l'inconnu'Decision theory provides computational techniques which quantify the value of information and guide decisions under uncertainty. These latter are very relevant for economic calculation under uncertainty, but they ignore the value of the unknown. It is now well-proved that such techniques are unsuitable, even misleading in a situation that contains unknown. Does this mean that in the unknown, economic calculators should give up any form of computational approach and only rely on intuitions? Or could we contemplate a computational technique that isolates and assesses economic effects in the unknown? This research work provides some insights to these questions by studying economic phenomena in the commercial aircraft industry, where economic calculation is massively used (profitability analyzes, costing analyzes...), and by mobilizing design theory models which account for the emergence of the unknown. A first research axis investigates the impacts of the unknown in rule-based design. We seek to understand the extent to which the unknown may impact a product development cost evolution dynamics by simulating the relationship between functional expansion and development cost escalation. We find that functional expansion introduces shocks in product architecture, the cost impact of which may be dramatic. And we study how well-known cost management techniques (modularization, anticipative overinvestment) could reduce costs under functional expansion. This leads to discuss how the misuse of classic cost reduction techniques under functional expansion could generate industrial catastrophes. A second axis focuses on investment cases whose huge economic returns seem incomprehensible in a decision-theoretic framework. We demonstrate that the unknown has played a role in the generation of these returns. And we show that specific methods and managerial principles were used to rigorously explore the unknown and generate such returns. The outcomes of this work suggest that the unknown can be managed as an economic variable in its own right, which raises further questions, namely about the kind of organizations that could deploy and operate ‘economic calculation in the unknown’
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Ruiz, Carbayo Helena. „The role of landscape and species attributes in insect community assembly, population genetics and plant-insect interactions in expanding Quercus ilex forests“. Doctoral thesis, Universitat Autònoma de Barcelona, 2018. http://hdl.handle.net/10803/650282.
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Los mecanismos responsables de la colonización y coexistencia de las especies en los hábitats,
es uno de los mayores rompecabezas en ecología de comunidades. Varias teorías, entre ellas la
teoría de nicho, neutral y de coexistencia, han intentado explicar la biodiversidad observada en
los ecosistemas naturales como el resultado de procesos determinísticos, neutrales o una
combinación de ambos, respectivamente. Esta biodiversidad se estructurará primero en
comunidades y más tarde en interacciones bióticas que únicamente pueden ser entendidas
desde la doble perspectiva de la ecología del paisaje y las dinámicas de
metapoblaciones/metacomunidades. La pérdida de comunidades e interacciones bióticas ha
sido extensamente estudiada en hábitats en proceso de regresión y fragmentación, sin
embargo, no ha sido ese el caso del ensamblaje de comunidades e interacciones en hábitats
en expansión. En el actual contexto de cambio global, la transformación del suelo ha dado
lugar a la pérdida de y fragmentación de hábitat en diferentes ecosistemas, sin embargo, la
recuperación de hábitats naturales también se ha observado. Particularmente en Europa, el
abandono de los cultivos ya causado la aparición de mosaicos forestales. Especialmente en
estos hábitats parcheados, los procesos neutrales modulados por las características
espaciotemporales del paisaje así como la capacidad de dispersión de los organismos podría
estar jugando un papel crucial en el ensamblaje de las comunidades de las interacciones
bióticas. Sin embargo, otros procesos determinísticos también podrían estar actuando a otras
escalas espaciales El objeto de esta tesis es la de ahondar en el conocimiento de los factores
que dirigen el ensamblaje de las comunidades y las interacciones bióticas, considerando como
sistema de estudio la interacción planta-insecto establecida entre Quercus ilex y su comunidad
de insectos herbívoros (folívoros y granívoros). Los principales objetivos fueron: a) cuantificar
los efectos de las características individuales de Q. ilex como la edad, el tamaño de copa, la
conectividad, la genética y la localización, sobre el ensamblaje de los herbívoros y la
herbivoría, b) explorar los efectos de la edad y la conectividad del hábitat en combinación con
la capacidad de dispersión de los herbívoros, en el ensamblaje de la comunidad de granívoros
y la granivoría a diferentes escalas espaciales, y finalmente, c) elucidad si existen evidencias
genéticas dentro de la comunidad de depredadores de semillas de los efectos de las
diferencias en capacidad de dispersión en el espacio y el tiempo dentro del gremio de
granívoros. El Capítulo 2 muestra una compleja interacción entre la edad, tamaño de copa y
conectividad de los árboles situados en dehesas emergentes, con comunidades de
lepidópteros más abundantes, ricas y diversas en los árboles más viejos, grandes y mejor
conectados, mientras que la composición (alpha y beta) depende exclusivamente de la
distancia entre árboles. El Capítulo 3 muestra en efecto directo de la genética del árbol sobre
el daño por herbivoría, como también un efecto borde que beneficia a los insectos en el
interior del parche, mientras que un efecto interactivo de la edad y la conectividad de la
encina, provoca un fenómeno de asociación por resistencia entre las encinas que ya han
alcanzado el estatus de árbol. Encontramos más evidencias del impacto de las características
individuales del árbol sobre la herbivoría en el Capítulo 4, donde la depredación de bellotas es
regulada por el tamaño de la bellota y la conectividad del árbol, mientras que dicha herbivoría
no cambia entre hábitats o paisajes a la escala local y regional, debido a dinámicas
compensatorias entre las distintas especies del gremio de granívoros (diferentes gremios a
escala local pero un efecto nulo del paisaje sobre la depredación de bellotas a escala de
paisaje) Además de estos efectos en la composición, en el Capítulo 5 los resultados revelan
una estructura genética significativa y una baja variabilidad local sólo para la especie que peor
dispersa en el espacio, C. elephas, además de mostrar una restricción en el flujo genético entre
bosques maduros y bosques nuevos aislados, de acuerdo con el crédito de colonización
revelado en el Capítulo 4. A pesar del efecto fundador, C. elephas presenta poblaciones más
abundantes que su especie hermana C. glandium, lo que podría sugerir que otros factores
están favoreciendo su fitness.
En general, nuestros resultados aportan información detallada sobre los procesos ecológicos
que están mediando el ensamblaje Quercus ilex – herbívoro en nuevos bosques y a diferentes
escalas.The mechanisms driving species colonization and coexistence in habitats, is one of the main puzzles in community ecology. Several theories, including niche, neutral and coexistence theories, have tried to explain the biodiversity observed in natural ecosystems as the result of deterministic, neutral, or a combination of both processes, respectively. This biodiversity will assemble in communities and ultimately biotic interactions which can only be fully understood by the double perspective of landscape ecology and metapopulation/metacommunity dynamics. Loss of communities and biotic interactions has been thoroughly studied in the context of shrinking and fragmented habitats, but has been poorly explored in expanding habitats. In the current context of global change, land transformation has resulted in loss and fragmentation of habitat in many different ecosystems, however, recovery of natural habitats has also been observed. Particularly in Europe, cropland abandonment has led to the emergence of patchy forest mosaics. Especially in these patchy habitats, neutral processes modulated by spatiotemporal landscape attributes as well as dispersal ability of organisms could be playing a key role in the assembly of communities and biotic interactions. Nevertheless, deterministic processes might as well be shaping communities and interactions at other spatial scales. The aim of this thesis has been to deepen in the knowledge of factors driving community and interaction assembly, taking as study system the plant-insect interaction established between Quercus ilex and its community of herbivore (folivore and granivore) insects. The main objectives were: a) to quantify the effects of Q. ilex individual characteristics such as tree age, size, connectivity, genetics and location, on the assembly of herbivore community and herbivory, b) to explore the effects of habitat age and connectivity in combination with herbivore dispersal ability, on the assembly of granivore community and granivory at different spatial scales, and finally, c) to elucidate if there already exists a genetic signature within the seed-predator guild derived from the differences in dispersal in time and space among species. Chapter 2 shows a complex interplay of age, canopy size and connectivity of trees interspersed in an expanding savannah-like Q. ilex landscape, leading to more abundant, richer and more diverse Lepidoptera communities in older, larger and more connected trees, while alpha and beta diversity depending exclusively on the distance between canopies. Chapter 3 shows a direct effect of tree genetics on the leaf damage suffered by holm oaks, as well as an edge effect benefiting insects at the core of the patch, while an indirect effect of age and connectivity, resulting in associational resistance, is revealed among mature developmental 2 stages of holm oak. Additional support of tree characteristic impact on herbivory is found in Chapter 4, where seed-predation is regulated by acorn size and tree connectivity, while it does not change between habitats or landscapes at the local and regional scales, due to compensatory dynamics of the different species within the seed-predator guild (different seedpredator assemblages at the local scale but zero-sum landscape effects on seed-predation at the landscape scale). In addition to effects on the composition of the community, in Chapter 5 results revealed significant genetic structure and low genetic variability only for the poorest disperser, C. elephas, as well as restricted gene flow between old and new-isolated patches, in consonance with colonization credits found for this species in Chapter 4. In spite of the founder effects, consistent larger populations of C. elephas compared to the better disperser C. glandium suggest that other factors are favoring the fitness of the former species. Overall, our results provide a detailed insight on the processes that are mediating the Quercus ilex – herbivore assembly in expanding forests at different spatial scales.
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Horta, Eduardo de Oliveira. „Uma análise funcional da dinâmica de densidades de retornos financeiros“. reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2011. http://hdl.handle.net/10183/30623.
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Uma correta especificação das funções densidade de probabilidade (fdp’s) de retornos de ativos é um tópico dos mais relevantes na literatura de modelagem econométrica de dados financeiros. A presente dissertação propõe-se a oferecer, neste âmbito, uma abordagem distinta, através de uma aplicação da metodologia desenvolvida em Bathia et al. (2010) a dados intradiários do índice bovespa. Esta abordagem consiste em focar a análise diretamente sobre a estrutura dinâmica das fdp’s dos retornos, enxergando-as como uma sequência de variáveis aleatórias que tomam valores em um espaço de funções. A dependência serial existente entre essas curvas permite que se obtenham estimativas filtradas das fdp’s, e mesmo que se façam previsões sobre densidades de períodos subsequentes à amostra. No artigo que integra esta dissertação, onde é feita a mencionada aplicação, encontrou-se evidência de que o comportamento dinâmico das fdp’s dos retornos do índice bovespa se reduz a um processo bidimensional, o qual é bem representado por um modelo var(1) e cuja dinâmica afeta a dispersão e a assimetria das distribuições no suceder dos dias. Ademais, utilizando-se de subamostras, construíram-se previsões um passo à frente para essas fdp’s, e avaliaram-se essas previsões de acordo com métricas apropriadas.Adequate specification of the probability density functions (pdf’s) of asset returns is a most relevant topic in econometric modelling of financial data. This dissertation aims to provide a distinct approach on that matter, through applying the methodology developed in Bathia et al. (2010) to intraday bovespa index data. This approach consists in focusing the analysis directly on the dynamic structure of returns fdp’s, seeing them as a sequence of function-valued random variables. The serial dependence of these curves allows one to obtain filtered estimates of the pdf’s, and even to forecast upcoming densities. In the paper contained into this dissertation, evidence is found that the dynamic structure of the bovespa index returns pdf’s reduces to a R2-valued process, which is well represented by a var(1) model, and whose dynamics affect the dispersion and symmetry of the distributions at each day. Moreover, one-step-ahead forecasts of upcoming pdf’s were constructed through subsamples and evaluated according to appropriate metrics.
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Wade, Jeremy 1981. „Summability of Fourier orthogonal expansions and a discretized Fourier orthogonal expansion involving radon projections for functions on the cylinder“. Thesis, University of Oregon, 2009. http://hdl.handle.net/1794/10245.
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vii, 99 p. A print copy of this thesis is available through the UO Libraries. Search the library catalog for the location and call number.We investigate Cesàro summability of the Fourier orthogonal expansion of functions on B d × I m , where B d is the closed unit ball in [Special characters omitted] and I m is the m -fold Cartesian product of the interval [-1, 1], in terms of orthogonal polynomials with respect to the weight functions (1 - z ) α (1 + z ) β (1 - |x| 2 ) λ-1/2 , with z ∈ I m and x ∈ B d . In addition, we study a discretized Fourier orthogonal expansion on the cylinder B 2 × [-1, 1], which uses a finite number of Radon projections. The Lebesgue constant of this operator is obtained, and the proof utilizes generating functions for associated orthogonal series.
Committee in charge: Yuan Xu, Chairperson, Mathematics; Huaxin Lin, Member, Mathematics Jonathan Brundan, Member, Mathematics; Marcin Bownik, Member, Mathematics; Jun Li, Outside Member, Computer & Information Science
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Lao, Ka Un. „Accurate and Efficient Quantum Chemistry Calculations for Noncovalent Interactions in Many-Body Systems“. The Ohio State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=osu1457973344.
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Wade, Jeremy. „Summability of Fourier orthogonal expansions and a discretized Fourier orthogonal expansion involving Radon projections for functions on the cylinder /“. Connect to title online (Scholars' Bank) Connect to title online (ProQuest), 2009. http://hdl.handle.net/1794/10245.
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Scheidt, Jrgen vom, Hans-Jrg Starkloff und Ralf Wunderlich. „Asymptotic Expansions for Second-Order Moments of Integral Functionals of Weakly Correlated Random Functions“. Universitätsbibliothek Chemnitz, 1998. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-199801269.
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In the paper asymptotic expansions for
second-order moments of integral functionals
of a class of random functions are considered.
The random functions are assumed to be
$\epsilon$-correlated, i.e. the values are not
correlated excluding a $\epsilon$-neighbourhood
of each point. The asymptotic expansions are
derived for $\epsilon \to 0$. With the help of
a special weak assumption there are found
easier expansions as in the case of general
weakly correlated functions.
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Rau, Christian, und rau@maths anu edu au. „Curve Estimation and Signal Discrimination in Spatial Problems“. The Australian National University. School of Mathematical Sciences, 2003. http://thesis.anu.edu.au./public/adt-ANU20031215.163519.
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In many instances arising prominently, but not exclusively, in imaging problems, it is important to condense the salient information so as to obtain a low-dimensional approximant of the data. This thesis is concerned with two basic situations which call for such a dimension reduction. The first of these is the statistical recovery of smooth edges in regression and density surfaces. The edges are understood to be contiguous curves, although they are allowed to meander almost arbitrarily through the plane, and may even split at a finite number of points to yield an edge graph. A novel locally-parametric nonparametric method is proposed which enjoys the benefit of being relatively easy to implement via a `tracking' approach. These topics are discussed in Chapters 2 and 3, with pertaining background material being given in the Appendix. In Chapter 4 we construct concomitant confidence bands for this estimator, which have asymptotically correct coverage probability. The construction can be
likened to only a few existing approaches, and may thus be considered as our main contribution.
¶
Chapter 5 discusses numerical issues pertaining to the edge and confidence band estimators of Chapters 2-4. Connections are drawn to popular topics which originated in the fields of computer vision and signal processing, and which surround edge detection. These connections are exploited so as to obtain greater robustness of the likelihood estimator, such as with the presence of sharp corners.
¶
Chapter 6 addresses a dimension reduction problem for spatial data where the ultimate objective of the analysis is the discrimination of these data into one of a few pre-specified groups. In the dimension reduction step, an instrumental role is played by the recently
developed methodology of functional data analysis. Relatively standar non-linear image processing techniques, as well as wavelet shrinkage, are used prior to this step. A case study for remotely-sensed navigation radar data exemplifies the methodology of Chapter 6.
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Bere, Alfred. „Comparison of HIV-1 specific T cell immunity in the female genital tract and blood of HIV-infected women : impact of in vitro T cell expansion on HIV-specific T cell specificity, maturational status and functional complexity“. Doctoral thesis, University of Cape Town, 2010. http://hdl.handle.net/11427/10081.
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Includes bibliographical references (leaves 161-184).This study shows that HIV-specific cervical T cells can be isolated by cytobrushing and in vitro polyclonal expansion is a useful approach to increase the number of T cells available from mucosal sites. Dynal beads (1:1) in the presence of IL-2, IL-7 and IL-15 resulted in the best yields of cervical T cells while anti-CD3 in the presence of IL-2 best conserved the ex vivo T cell profile. Expanded T cell lines, irrespective of expansion method used, generally maintain their cytokine response profile to HIV anti- gens. This study shows that HIV Gag-specific blood and cervical T cells were largely mono-functional with polyfunctional T cells being detected in women with high blood CD4 count and low plasma viral load. This study confirms that HIV-specific Gag T cell responses detected in the polyclonal expanded female genital tract T cells are associated with those measured in blood during HIV infection.
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Schwiegerling, Jim. „Optical transfer function expansion of quadratic pupils“. SPIE-INT SOC OPTICAL ENGINEERING, 2017. http://hdl.handle.net/10150/627185.
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Quadratic pupils representing Gaussian apodization and defocus are expanded into Zernike polynomials. Combinations of the pupil expansion coefficients are used, in turn to expand the Optical Transfer Function into a novel set of basis functions.
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Trasler, Simon Andrew. „Hig orders of Weyl expansions“. Thesis, Brunel University, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.241650.
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Dew, N. „Asymptotic structure of Banach spaces“. Thesis, University of Oxford, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.270612.
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The notion of asymptotic structure of an infinite dimensional Banach space was introduced by Maurey, Milman and Tomczak-Jaegermann. The asymptotic structure consists of those finite dimensional spaces which can be found everywhere `at infinity'. These are defined as the spaces for which there is a winning strategy in a certain vector game. The above authors introduced the class of asymptotic $\ell_p$ spaces, which are the spaces having simplest possible asymptotic structure. Key examples of such spaces are Tsirelson's space and James' space. We prove some new properties of general asymptotic $\ell_p$ spaces and also compare the notion of asymptotic $\ell_2$ with other notions of asymptotic Hilbert space behaviour such as weak Hilbert and asymptotically Hilbertian. We study some properties of smooth functions defined on subsets of asymptotic $\ell_\infty$ spaces. Using these results we show that that an asymptotic $\ell_\infty$ space which has a suitably smooth norm is isomorphically polyhedral, and therefore admits an equivalent analytic norm. We give a sufficient condition for a generalized Orlicz space to be a stabilized asymptotic $\ell_\infty$ space, and hence obtain some new examples of asymptotic $\ell_\infty$ spaces. We also show that every generalized Orlicz space which is stabilized asymptotic $\ell_\infty$ is isomorphically polyhedral. In 1991 Gowers and Maurey constructed the first example of a space which did not contain an unconditional basic sequence. In fact their example had a stronger property, namely that it was hereditarily indecomposable. The space they constructed was `$\ell_1$-like' in the sense that for any $n$ successive vectors $x_1 < \ldots < x_n$, $\frac{1}{f(n)} \sum_{i=1}^n \| x_i \| \leq \| \sum_{i=1}^n x_i \| \leq \sum_{i=1}^n \| x_i \|,$ where $ f(n) = \log_2 (n+1) $. We present an adaptation of this construction to obtain, for each $ p \in (1, \infty)$, an hereditarily indecomposable Banach space, which is `$\ell_p$-like' in the sense described above. We give some sufficient conditions on the set of types, $\mathscr{T}(X)$, for a Banach space $X$ to contain almost isometric copies of $\ell_p$ (for some $p \in [1, \infty)$) or of $c_0$. These conditions involve compactness of certain subsets of $\mathscr{T}(X)$ in the strong topology. The proof of these results relies heavily on spreading model techniques. We give two examples of classes of spaces which satisfy these conditions. The first class of examples were introduced by Kalton, and have a structural property known as Property (M). The second class of examples are certain generalized Tsirelson spaces. We introduce the class of stopping time Banach spaces which generalize a space introduced by Rosenthal and first studied by Bang and Odell. We look at subspaces of these spaces which are generated by sequences of independent random variables and we show that they are isomorphic to (generalized) Orlicz spaces. We deduce also that every Orlicz space, $h_\phi$, embeds isomorphically in the stopping time Banach space of Rosenthal. We show also, by using a suitable independence condition, that stopping time Banach spaces also contain subspaces isomorphic to mixtures of Orlicz spaces.
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Rustaey, Abid 1961. „A comparison of conventional acceleration schemes to the method of residual expansion functions“. Thesis, The University of Arizona, 1989. http://hdl.handle.net/10150/277176.
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The algebraic equations resulting from a finite difference approximation may be solved numerically. A new scheme that appears quite promising is the method of residual expansion functions. In addition to speedy convergence, it is also independent of the number of algebraic equations under consideration, hence enabling us to analyze larger systems with higher accuracies. A factor which plays an important role in convergence of some numerical schemes is the concept of diagonal dominance. Matrices that converge at high rates are indeed the ones that possess a high degree of diagonal dominance. Another attractive feature of the method of residual expansion functions is its accurate convergence with minimal degree of diagonal dominance. Methods such as simultaneous and successive displacements, Chebyshev and projection are also discussed, but unlike the method of residual expansion functions, their convergence rates are strongly dependent on the degree of diagonal dominance.
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Borenstein, Evan. „Additive stucture, rich lines, and exponential set-expansion“. Diss., Atlanta, Ga. : Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/29664.
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Thesis (Ph.D)--Mathematics, Georgia Institute of Technology, 2009.Committee Chair: Croot, Ernie; Committee Member: Costello, Kevin; Committee Member: Lyall, Neil; Committee Member: Tetali, Prasad; Committee Member: Yu, XingXing. Part of the SMARTech Electronic Thesis and Dissertation Collection.
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Tripathi, Hemant Gangaprasad. „Biodiversity of the African savanna woodlands : how does it change with land use?“ Thesis, University of Edinburgh, 2018. http://hdl.handle.net/1842/28965.
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The savanna woodlands of Southern Africa, colloquially termed the miombo, are poorly described in terms of biodiversity compared to other biomes. They have therefore been underrepresented in the wider understanding of how land use intensification is shaping global biodiversity. Land use change is known to reduce biodiversity and disrupt intactness of ecological communities with consequences for ecosystem functioning, resilience, and services. Miombo woodlands are described as biodiversity hotspots due to a high endemism of species and the presence of megafauna. At the same time, they are also considered dynamic socio-ecological systems shaped by disturbances and the land use activities of people. The patterns of biodiversity change in these tropical ecosystems may, therefore, have their own unique contexts, understanding of which will be essential for biodiversity and land use management in these ecosystems. In this thesis, I identified the patterns of biodiversity change in response to the two major land use practices in the two dominant woodland types in southern African woodlands: the selective logging due to charcoal production in the mopane woodlands, and agricultural expansion in the miombo. I also examined the impact of two main disturbance agents, humans and elephants, on habitat structure and biodiversity in mopane woodlands. Across all chapters in this thesis, I investigated the effects of land use change and habitat modification on biodiversity empirically using chronosequences. To understand biodiversity change, I employed a hierarchical multilevel modelling approach making inferences at the three levels of ecological communities: species, community, and meta-community (set of ecological communities at different sites). I selected six villages in the charcoal production hotspot of southern Mozambique and carried out field surveys for three taxonomic groups: trees, mammals and ground beetles. I modelled the counts of trees and beetles and incidence of mammals using meta-community occurrence models in a Bayesian framework with the intensity class of the villages, above-ground biomass and land cover type as predictors. The results suggested that the species richness of trees and mammals declined by 12 and 8.5 % respectively while that of beetles increased by 3.5%, albeit non-significantly. In addition, the beta diversity of trees decreased while that of mammals increased. The results show that while both trees and mammals reduced in richness, they responded differently to charcoal production in terms of community organisation. The trees underwent subtractive homogenisation (decrease in alpha and beta diversities) primarily because of deterministic processes induced by selective harvesting of tree stems for charcoal. Mammal communities, on the other hand, showed subtractive heterogenization (decrease in alpha, but increase in beta diversity) mainly due to random extinctions. In the agriculture frontier of miombo-dominated northern Mozambique, I investigated the effects of fragmentation and habitat loss caused by agricultural expansion on diversity and composition of trees and mammals. I modelled the occurrences of trees and mammals using occupancy models with the fragmentation and quantity of woodland cover as predictors. The model showed that most tree species (n=10), mainly the timber and firewood species, linearly declined in population size as fragmentation increased. Mammals, on the other hand, showed a nonlinear response. Seven mammal species increased at the lower levels of fragmentation. However, at the higher levels, none of the mammal species increased while two declined. Similarly, the species richness of trees linearly declined, while that of mammals increased up to a fragmentation level of 55-65% and declined above this limit. The beta diversity of trees increased with fragmentation while that of mammals decreased. The results suggest that, although fragmentation reduces species richness of both trees and mammals, it affects their species compositions in different ways. Trees undergo subtractive heterogenization due to random species losses while mammals experience subtractive homogenisation mainly due to the combined effects of fragmentation-led habitat loss and intensified hunting. Finally, this study concludes that, above 75% fragmentation or below 26% habitat quantity, both taxonomic groups endure biodiversity loss. The threshold results here corroborate similar habitat quantity thresholds (20-30%) observed elsewhere in different ecosystems. However, they differ with the widespread notion that above 30% habitat quantity, the effect of fragmentation is non-existent. The results here emphasize that taxonomic groups respond differently, the diversity and population size of mammals reduced only after the habitat threshold, whereas, those of trees showed linear decrease with fragmentation most likely due to fragmentation-led habitat loss. Lastly, I examined the effects of disturbance by humans and elephants on habitat structure and bird diversity by conducting a space for time substitution comparison in the mopane woodlands of Zambia. To examine the woodland structure, I modelled the structural attributes of habitat (stem diameter, stand density, and basal area) using mixed models with the proportion of affected stems by humans and elephants as explanatory variables. I found that elephant disturbance was associated with higher stem diameters, low stand densities, but no change in basal area. Human disturbance, on the other hand, was related to reductions in stand density and basal area, but no change in the stem diameter. Further, I tested species and functional diversity of birds against the covariates of habitat structure and disturbance. I found that bird communities reduced in species richness in both, human as well as elephant disturbed areas. However, the functional diversity did not change with elephant disturbance. I concluded that human disturbance reduces woody biomass (basal area is correlated with woody biomass) of mopane woodlands and functional diversity of birds whilst elephants do not. In this thesis, I conclude that human driven land use change in the miombo woodlands erodes alpha diversity of all taxonomic groups. However, increases in beta diversity of mammals with charcoal land use and trees in agricultural land use may maintain their diversities at the meta-community level.
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Miller, Raymond Russell. „Mosquito Odorant Receptors: C-terminal Motifs, Subfamily Expansion, and Function“. Diss., Virginia Tech, 2008. http://hdl.handle.net/10919/28323.
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Many insects rely on olfaction as their primary method of interaction with their environment. One of the best examples of this is the olfactory driven host-seeking behavior displayed by female mosquitoes. Although mosquitoes are capable of extracting blood from a variety of hosts many mosquito species show marked preferences for particular host species. Mosquitoes displaying preference for humans above bovines are more likely to be disease vectors. Therefore understanding the molecular basis of this preference is important for public health. These differences may be the result of genetic variations in olfactory signaling components such as mosquito odorant receptors. This hypothesis is supported by several lines of evidence including the highly divergent and lineage-specific nature of this receptor family. Likely these differences are subtle and will be identified in highly focused studies. Even closely related sibling species of mosquitoes can display large behavioral differences. In our current study I have studied several aspects of both Anopheles and Aedes genus odorant receptors with emphasis on comparing receptors in species that are part of the Anopheles genus.
The first goal of this project was to study the insect odorant receptor family for potential sites of heterodimer formation. Numerous studies have shown that insect odorant receptors are involved in detection of odorants. More recent studies have demonstrated that odorant receptors are also involved in protein trafficking and in forming cation channels. Both of these activities involve heterodimer formation between odorant receptors that bind odorants and those that are part of the Or83b subfamily. There is little informaiton on how heterodimers are formed and where within the protein heterodimer sites exist. The C-terminal region has been implicated as sites for such heterodimer formation. A hidden markov model based program, Multiple em for motif elicitation (MEME), was used to uncover three motifs in the C-terminus of the odorant receptor peptides from Anopheles gambiae, D. melanogaster, and Apis mellifera. Previous studies have shown that insect odorant receptors are highly divergent between different insect lineages suggesting conservation of these motifs is functionally important. I propose that these motifs are involved in receptor-receptor protein interactions, contributing to the heterodimer formation between Or83b subfamily members and other odorant receptors.The next goal was to identify odorant receptors in closely related mosquito species and compare and contrast them. This was accomplished by using public sequence data of An. gambiae and BAC library screening to identify orthologous gene clusters in An. stephensi and An. quadriannulatus. Although I have identified many different odorant receptor genes the chapter in this dissertation discusses my work with the Or2 gene cluster. Multi-species comparison of these orthologous regions in An. gambiae, An. quadriannulatus, and An. stephensi revealed highly conserved gene structure among the OR genes and the discovery of the An. stephensi Or10x gene (AsOr10x), which is present only in An. stephensi. AsOr10x showed a different expression pattern than AsOr2 and AsOr10, the other members of this gene subfamily in An. stephensi. Therefore AsOr10x might be adapting or has adapted a new function. Analysis of the phylogeny and physical location of all known members of the Or2/Or10 gene subfamily in Anopheles, Aedes, and Culex mosquitoes suggest that a few events of gene duplication and loss resulted in the current gene distribution.
The final focus of this project was to develop a method to study the function of mosquito odorant receptors. There is currently no in vivo system to study mosquito odorant receptors, and experimental systems pioneered in D. melanogaster are not transferable to mosquitoes. I decided to employ a reverse genetics strategy involving the silencing of three Aedes aegypti odorant and gustatory receptors of known or suspected function. These gustatory receptors are members of a small subfamily that encode olfactory and not taste receptors. As a preliminary step the expression profiles of these three genes and an additional gustatory receptor were determined using non-quantitative and quantitative RT-PCR. We found that the putative CO₂-detecting gustatory receptors are expressed in Ae. aegypti larvae, and hence these larvae may respond to CO₂, an observation that has not been reported previously.
The purpose of silencing these receptors is to generate a loss-of-function behavior phenotype that will allow for inference of receptor function. Recombinant Sindbis viruses were used to knockdown mRNA levels of these receptors. GFP-expressing recombinant Sindbis viruses were shown to infect chemosensory tissue. Additional viruses containing fragments of receptor genes were found capable of lowering odorant and gustatory receptor mRNA levels. Infected mosquitoes displayed varying levels of gene knockdown with one virus generating supression of mRNA levels to 15.0% of normal. These mRNA levels may not be low enough to generate an unambiguous phenotype. Future experimentation is focused on developing more effective recombinant viruses and identifying characteristics of viruses more effective in receptor gene knockdown. A safe and effective behavior assay setup is needed to test the behavioral responses of these infected mosquitoes. In this study I outline a preliminary behavior assay that is being developed and optimized. When established it will provide a powerful tool in the study of both basic mosquito behavior and phenotype screening of recombinant Sindbis virus-infected mosquitoes.Ph. D.
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Pierce, Virgil. „The asymptotic expansion of the partition function of random matrices“. Diss., The University of Arizona, 2004. http://hdl.handle.net/10150/280566.
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We explore two methods for calculating the Taylor Coefficients of the terms of the asymptotic expansion of the partition function of random matrices for specific even potentials. The first of these methods applies to the leading order term. We show that this term has an elementary form in terms of a solution to an algebraic equation. This generates a general formula for the Taylor Coefficients of this term. Next we exploit the relationship between orthogonal polynomials and the Toda Lattice Equations to derive ODE's for the general terms of the expansion of the partition function of random matrices, which leads to a method of calculating the Taylor Coefficients of these functions.
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Starkloff, Hans-Jörg. „Higher order asymptotic expansions for weakly correlated random functions“. Doctoral thesis, Universitätsbibliothek Chemnitz, 2005. http://nbn-resolving.de/urn:nbn:de:swb:ch1-200500122.
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Die vorliegende Arbeit beschäftigt sich mit asymptotischen Entwicklungen höherer Ordnung für zweite Momente von Zufallsvariablen bzw. Zufallsfunktionen, die als lineare Integralfunktionale über schwach abhängige oder
schwach korrelierte Zufallsfunktionen definiert sind. Unter bestimmten Glattheits- und Integrabilitätsbedingungen an die Kernfunktionen
und Regularitätsbedingungen an die Zufallsfunktionen werden
entsprechende asymptotische Entwicklungen
angegeben, außerdem wird auf Abschätzungen der
Genauigkeit eingegangen. Die auftretenden Zufallsfunktionen sind dabei stationäre reell- oder vektorwertige Zufallsprozesse, bestimmte Klassen nichtstationärer Zufallsprozesse und homogene Zufallsfelder. Die Anwendungsmöglichkeit wird an einer Reihe von Beispielen aufgezeigt.
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Girdhar, Anupam. „Expansion of Group Technology Part Coding Based on Functionality“. University of Cincinnati / OhioLINK, 2001. http://rave.ohiolink.edu/etdc/view?acc_num=ucin990649367.
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Pillay, Samara. „The narrow escape problem : a matched asymptotic expansion approach“. Thesis, University of British Columbia, 2008. http://hdl.handle.net/2429/1428.
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We consider the motion of a Brownian particle trapped in an arbitrary bounded two or three-dimensional domain, whose boundary is reflecting except for a small absorbing window through which the particle can escape. We use the method of matched asymptotic expansions to calculate the mean first passage time, defined as the time taken for the Brownian particle to escape from the domain through the absorbing window. This is known as the narrow escape problem. Since the mean escape time diverges as the window shrinks, the calculation is a singular perturbation problem. We extend our results to include N absorbing windows of varying length in two dimensions and varying radius in three dimensions. We present findings in two dimensions for the unit disk, unit square and ellipse and in three dimensions for the unit sphere. The narrow escape problem has various applications in many fields including finance, biology, and statistical mechanics.
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EGAMI, SHIGEKI, und KOHJI MATSUMOTO. „ASYMPTOTIC EXPANSIONS OF MULTIPLE ZETA FUNCTIONS AND POWER MEAN VALUES OF HURWITZ ZETA FUNCTIONS“. Cambridge University Press, 2002. http://hdl.handle.net/2237/10284.
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Wurjantara, Wisnu. „Computation of current distribution in long elliptic conductors using Mathieu functions expansion“. Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp04/mq28693.pdf.
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Lladser, Manuel Eugenio. „Asymptotic enumeration via singularity analysis“. Connect to this title online, 2003. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1060976912.
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Thesis (Ph. D.)--Ohio State University, 2003.Title from first page of PDF file. Document formatted into pages; contains x, 227 p.; also includes graphics Includes bibliographical references (p. 224-227). Available online via OhioLINK's ETD Center
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Navas, Palencia Guillermo. „High-precision computation of uniform asymptotic expansions for special functions“. Doctoral thesis, Universitat Politècnica de Catalunya, 2019. http://hdl.handle.net/10803/667810.
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In this dissertation, we investigate new methods to obtain uniform asymptotic expansions for the numerical evaluation of special functions to high-precision. We shall first present the theoretical and computational fundamental aspects required for the development and ultimately implementation of such methods. Applying some of these methods, we obtain efficient new convergent and uniform expansions for numerically evaluating the confluent hypergeometric functions and the Lerch transcendent at high-precision. In addition, we also investigate a new scheme of computation for the generalized exponential integral, obtaining on the fastest and most robust implementations in double-precision floating-point arithmetic.
In this work, we aim to combine new developments in asymptotic analysis with fast and effective open-source implementations. These implementations are comparable and often faster than current open-source and commercial stateof-the-art software for the evaluation of special functions.Esta tesis presenta nuevos métodos para obtener expansiones uniformes asintóticas, para la evaluación numérica de funciones especiales en alta precisión. En primer lugar, se introducen fundamentos teóricos y de carácter computacional necesarios para el desarrollado y posterior implementación de tales métodos. Aplicando varios de dichos métodos, se obtienen nuevas expansiones uniformes convergentes para la evaluación numérica de las funciones hipergeométricas confluentes y de la función transcendental de Lerch. Por otro lado, se estudian nuevos esquemas de computo para evaluar la integral exponencial generalizada, desarrollando una de las implementaciones más eficientes y robustas en aritmética de punto flotante de doble precisión. En este trabajo, se combinan nuevos desarrollos en análisis asintótico con implementaciones rigurosas, distribuidas en código abierto. Las implementaciones resultantes son comparables, y en ocasiones superiores, a las soluciones comerciales y de código abierto actuales, que representan el estado de la técnica en el campo de la evaluación de funciones especiales.
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Foster, T. D. „Power functions and exponentials in o-minimal expansions of fields“. Thesis, University of Oxford, 2010. http://ora.ox.ac.uk/objects/uuid:24b2d0d2-b0d7-42e5-aa80-e4e0bda56c9a.
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The principal focus of this thesis is the study of the real numbers regarded as a structure endowed with its usual addition and multiplication and the operations of raising to real powers. For our first main result we prove that any statement in the language of this structure is equivalent to an existential statement, and furthermore that this existential statement can be chosen independently of the concrete interpretations of the real power functions in the statement; i.e. one existential statement will work for any choice of real power functions. This result we call uniform model completeness. For the second main result we introduce the first order theory of raising to an infinite power, which can be seen as the theory of a class of real closed fields, each expanded by a power function with infinite exponent. We note that it follows from the first main theorem that this theory is model-complete, furthermore we prove that it is decidable if and only if the theory of the real field with the exponential function is decidable. For the final main theorem we consider the problem of expanding an arbitrary o-minimal expansion of a field by a non-trivial exponential function whilst preserving o-minimality. We show that this can be done under the assumption that the structure already defines exponentiation on a bounded interval, and a further assumption about the prime model of the structure.
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Conrad, Eric van Fossen. „Some Continued Fraction Expansions of Laplace Transforms of Elliptic Functions“. The Ohio State University, 2002. http://rave.ohiolink.edu/etdc/view?acc_num=osu1029248229.
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MATSUMOTO, KOHJI, und MASANORI KATSURADA. „Explicit Formulas and Asymptotic Expansions for Certain Mean Square of Hurwitz Zeta-Functions: III“. Cambridge University Press, 2002. http://hdl.handle.net/2237/10253.
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Shankar, Sushma. „Ex vivo expansion of human IL-10+ B cells with regulatory function“. Thesis, University of Oxford, 2016. https://ora.ox.ac.uk/objects/uuid:fa041dce-0095-4d0f-8089-5e7103124e02.
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Introduction: Solid organ transplantation is the gold standard therapy for many end-stage organ diseases. Although short-term graft survival is excellent due to the use of potent immunosuppressive regimens, incidence of chronic allograft dysfunction and graft failure remains unchanged. Global immunosuppressants are also associated with adverse side effects including severe infection, malignancy and target end-organ damage. Novel, targeted approaches are required to more effectively modulate the immune system and to improve long-term graft outcomes. One such strategy is that of cellular therapy. An enriched population of human IL-10+ B cells with regulatory function (Breg) has been identified in tolerant, human kidney transplant recipients; mouse IL-10+ Breg confer protection of allograft in mouse models of transplantation. However, human Breg are poorly characterised, are rare in peripheral blood and there is currently no method by which to obtain such cells in large numbers; thus limiting the potential for human Breg as a clinical therapy. Here we describe, for the first time, ex vivo generation and characterisation of human IL-10+ B cells with both in vitro and in vivo regulatory function (EXPB10 cells). Methods: Human CD19+ B cells from healthy individuals were negatively selected and stimulated for 7 days with CD154+ CHO cells and the cytokine combination IL-2, IL-4 and IL-10 to generate IL-10+ B cells. Phenotype and suppressive function of EXPB10 cells were examined in vitro. The ability of EXPB10 cells to regulate in vivo immune responses was tested using a clinically relevant humanised mouse model of skin transplantation. Human CD19+ B cells in peripheral blood from both healthy human subjects and patients suffering from squamous cell carcinoma of the skin were examined for human Breg subsets by flow cytometry. Results: EXPB10 cells produced IL-10, up-regulated expression of the putative Breg marker TIM-1, and suppressed CD4+ T cell proliferation and Th1 cell differentiation in vitro. Suppression was partially dependent on IL-10 and CD154. EXPB10 cells were highly activated, CD19+TIM-1+CD25+CD71+CD73- B cells which demonstrated dependency on autocrine IL-10. TIM-1 may have modulated intracellular pathways downstream of IL-10, thereby driving EXPB10-mediated suppression of CD4+ T cell responses. A second, CD154-independent suppressive mechanism was identified which may rely on purinergic signaling. EXPB10 cells significantly prolonged human graft survival in a humanised mouse model of skin transplantation and were able to generate and expand functionally suppressive human T regulatory cells (Treg). Examination of CD19+ B cells in human peripheral blood identified an endogenous CD19+CD25+CD71+CD73- B cell subset which was enriched for TIM-1, similar to EXPB10 cells. This endogenous B cell subset was also significantly enriched in patients with squamous cell carcinoma of the skin compared to a control cohort of healthy human subjects. Discussion: Human CD19+IL-10+ B cells with regulatory function can be generated ex vivo and can prolong human allograft survival in a complex, biological environment. Mechanistic data demonstrated that this human Breg subset was dependent on the cognate interaction between CD154 and CD40, as well as the autocrine action of IL-10. TIM-1 may act as a gatekeeper of regulatory function by modulating the EXPB10 cell's response to IL-10. Such subtleties in cellular behaviour offer the potential for further manipulation to better control an immune response. The identification of CD19+ B cells in human peripheral blood with a similar phenotype as EXPB10 cells, and moreover the finding that this subset was enriched in patients diagnosed with cancer, suggests that endogenous Breg may exist with similar cellular properties to that of EXPB10 cells. This potent suppressor population may represent a novel cellular therapy which could be used alone or as an adjunct to other immunosuppressive regimens in the context of transplantation, autoimmunity and inflammation.
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Aspenberg, Magnus. „The Collet-Eckmann condition for rational functions on the Riemann sphere“. Doctoral thesis, KTH, Mathematics, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3788.
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