Thèses : « Growth and evolution »

1

Maniou, Zoitsa. « Molecular evolution of pituitary growth hormone ». Thesis, University of Sussex, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.270719.

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Huang, Jie. « Growth, evolution and scaling in transport networks ». Thesis, University of Leeds, 2015. http://etheses.whiterose.ac.uk/9966/.

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Under urbanisation, transport infrastructures may be improved when urban population grows. Meanwhile, land use patterns may vary and this urban dynamics may drive variations in mode choice of commuters and spatial features of transport networks. Empirical studies have observed scaling laws between the amount of transport infrastructures and city sizes. This thesis is aiming to provide a modelling framework for the analytical investigation of network growth and present some empirical observations of the variation in spatial features of transport networks. First, a simple linear monocentric city model is formulated and the global performance of transport systems is derived. Two cases according to strategies of urban intensification and sprawl have been studied to examine the consequence of the scaling-law growth in transport infrastructures. Second, this thesis proposes a modelling framework. The framework includes two congestible modes, the scaling-law growth of transport infrastructures and housing allocation of residents so that phenomena under urban dynamics could be modelled. The experiments show that the proposed modelling framework could investigate the trade-off of investment on the highway and public transport system. Third, empirical observations of spatial features in transport networks are reported in this thesis. The thesis measures circuity of transport networks, because this indicator could examine how aggregate transport networks are and the efficiency of network structures. Then research methods that can deal with several data sources are developed. The empirical observation shows that there is an exponential decay between the circuity and travel time in public transport networks. Meanwhile, this thesis also presents that the average circuity in road networks is less than that in public transport networks for the same sample of trips, which to some extent show the difference of spatial features between road and public transport networks. Additionally, correlations between circuity, accessibility and mode share are analysed.

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King, Annette. « On the evolution of growth and senescence ». Thesis, University of Newcastle upon Tyne, 2016. http://hdl.handle.net/10443/3453.

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Consistent associations between growth and senescence are seen throughout nature. Whilst a larger size correlates positively with lifespan between species, this relationship is reversed within a species so that the smallest members tend to be the longest‐lived. Indeterminate growth ‐ i.e. growth that continues post‐maturity ‐ is a strong predictor for an especially slow rate of ageing. A number of interventions which alter the rate of growth, especially at a point early in development, have been shown to have enduring effects on later growth and lifespan. This thesis provides a theoretical examination of why relationships such as these may have evolved. Two dynamic programming models are here presented. Both consider associations between growth and longevity within a species and ask whether these are compatible with idea of a trade‐off between somatic maintenance and other fitness‐enhancing functions as predicted by the disposable soma theory. The first reproduces the sexual dimorphism in longevity and in body size seen baboons; it predicts that males should ‘choose’ a faster rate of ageing and a greater investment in growth than females. The second suggests that a faster rate of ageing may be an optimal response to low food availability in early life in humans. A critical appraisal is also given to two recent theories of the evolution of ageing which rely explicitly on differences in body size and/or growth to explain differences in lifespan: the hyperfunction theory and the heat dissipation limit theory. What these can teach us about the evolution of senescence and whether they can provide plausible challenges to the disposable soma theory is considered.

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Phegley, Jeff S. « Terrestrial evolution ». Virtual Press, 2001. http://liblink.bsu.edu/uhtbin/catkey/1266141.

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Terrestrial Evolution focuses on the destruction of the natural environment by manmade obstructions such as housing developments, strip malls, roads, telephone lines, and utility poles. Each of the paintings address one or more of these aspects of development and communicates ideas of detachment from this seemingly endless process of building. Color, surface texture, composition, and visual imagery were all carefully thought out and planned parts of a complicated process for the communication of ideas on this particular subject matter.My hometown of Carmel, Indiana has been experiencing massive environmental change over the past ten years. Large housing editions and strip malls have been built to accommodate the influx of people moving to this northern suburb of Indianapolis. Land is being sold, bought, zoned, and covered with quickly built homes and strip malls. Once this suburban sprawl has begun, will it stop? How much of the environmental damage it has contributed is reversible?Terrestrial Evolution represents a very personal and visual response to the contemporary state of Carmel's woodlands, wetlands, and wildlife, which are being sacrificed for manmade development.
Department of Art

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5

Racca, Simone. « Some models of crack growth in brittle materials ». Doctoral thesis, SISSA, 2013. http://hdl.handle.net/20.500.11767/4809.

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This work is devoted to the study of models of fractures growth in brittle elastic materials; it collects the results obtained during my Ph.D., that are contained in [77, 76, 78]. We consider quasi-static rate-independent models, as well as rate-dependent ones and the case in which the first ones are limits of the second ones when certain physical parameters vanish. The term quasistatic means that, at each instant, the system is assumed to be in equilibrium with respect to its time-dependent data; this setting is typical of systems whose internal time scale is much smaller than that of the loadings. By rate-independent system we mean that, if the time-dependent data are rescaled by a strictly monotone increasing function, then the system reacts by rescaling the solutions in the same manner.

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Carel, Roland. « Grain growth and texture evolution in thin films ». Thesis, Massachusetts Institute of Technology, 1995. http://hdl.handle.net/1721.1/31064.

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Dey, Bhakta Ranjan. « Transforming growth factor-β3 gene structure and evolution ». Thesis, University of Edinburgh, 1991. http://hdl.handle.net/1842/13639.

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Transforming growth factor-β (TGF-β) is a multifunctional regulator of cellular proliferation and differentiation. It has been suggested that members of the TGF-β gene family also control differentiation and morphogenesis in embryonic developments. Since the chicken embryogenesis has been so extensively studied, we chose to clone the chicken TGF-β3 gene to facilitate a more detailed analysis of the developmental role of TGF-βs. We have cloned and characterised the chicken TGF-β3 gene and its flanking regions from a White Leghorn chicken genomic library packaged into λEMBL3 using chicken TGF-β3 exon specific oligonucleotide probes. We have determined the gene structure from overlapping genomic clones. The chicken TGF-β3gene contains 7 exons and 6 introns, spanning 15.6kb of genomic DNA. The intron/exon organisation was initially characterised on the basis of Southern blot analysis using exon specific oligonucleotide probe(s) and subsequently confirmed by DNA sequencing. We have also characterised the chicken TGF-β3 promoter. The promoter is very GC-rich and lies within an extensive CpG island of approximately 2400 nucleotides. The 5'-untranslated region is 467 bp, in length shorter than that found in the human TGF-β3 gene (1356 bp). A comparison of the 5'-flanking regions from the chicken and human TGF-β3 genes revealed two regions of sequence homology: an 86 bp sequence surrounding the transcription start and a 156 bp sequence in the 5'-untranslatedregion. The conserved region near the transcription start contains short sequences that resemble TATA box, cAMP responsive element (CRE), and AP-2 consensus motifs. These are cis acting sequences we believe may be important for promoter activity. The conserved region in the 5'-untranslated region is also present in chicken, mouse, porcine and human TGF-β3genes and may have a regulatory role. The chicken TGF-β3 promoter has no sequence homology with either TGD-β2 promoters. We do, however, find some striking similarities between TGF-β2 and TGF-β3 promoters, including the conserved regulatory sequences of TATA box, CRE and AP-2 sequence motifs near the transcription initiation site. A computer assisted search of the chicken TGF-β3 gene nucleotide sequence identified several other potential binding sites for known regulatory proteins. Besides the above, these include the recognition sequences for the transcription factors TFIID, MyoDl, Spl, PEA3, Krox-24 and GRE. Further studies on TGF-β3 gene regulation should determine the significance of these regulatory protein binding sites. The 3'-untranslated region of the gene is approximately 956 bp in length. A sequence comparison of chicken TGF-β3 3' flanking sequence with the published cDNA sequences of mouse, porcine and human TGF-β3 reveals a highly conserved 84 bp segment around the polyadenylation signal.

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Morgan, Daniel Ashley. « The growth and evolution of polygonal fault tiers ». Thesis, Cardiff University, 2016. http://orca.cf.ac.uk/88909/.

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Polygonal faults are layer-bound arrays of normal faults confined to specific stratigraphic intervals called tiers. Typically hosted in fine-grained sediments, polygonal faults are thought to have the potential for fluid leakage and represent a potential seal bypass mechanism. Intergral to understanding the impact of polygonal faults on regional top seal is timing and evolution of polygonal fault tiers. Whilst there are numerous studies imaging and describing polygonal faults in numerous basins around the world, very few specifically consider the growth of polygonal faults. Additionally, very few polygonal fault studies examine the evolution of fault hierarchies and how these hierarchies accommodate strain and deformation within the tier. This study examines two wedge-shaped polygonal fault tiers on different passive margins. The first polygonal fault tier studied is from offshore Angola and is hosted in sediment thickness of less 500 m, in Plio-Pleistocene claystones. The second tier examined is from the Modgunn Arch, Norwegian Margin and is hosted in a sequence of siliceous oozes and claystones of Eocene to Pliocene age, up to 1200 m in thickness. This study uses the differences in sediment ages to compare and contrast polygonal fault tiers at different stages of evolution and aims to examine common features between young and mature tiers in order to constrain tier evolution. This study considers two aspects of polygonal fault growth. Firstly it considers the utility of perturbations in polygonal fault tiers around features of the base of the tier. These perturbations have the potential to be a useful proxy for elucidating the nucleation position of polygonal faults in the tier. The second aspect of polygonal fault tier evolution reviews the mechanisms that control organisation hierarchies within a tier and examines the role of linkage in creating large master polygonal faults. The results of this thesis show that the polygonal faults can initiate at low temperatures and low pressures, in sediment thickness of 100 m or less. Moreover, it can be demonstrated that polygonal fault tips propagate preferentially upwards with basal tips pinned by a mechanical boundary at the base of the tier and lateral tips pinned by early forming branchline intersections. The transition from shallow to deep burial shows that polygonal fault hierarchies are naturally forming and may relate to variation in the propagation rate of polygonal faults within the tier. With increasing burial, there 3 is an increased likelihood of branchline interaction. Branchline interaction can occur laterally with lateral tips abutting against other faults in the network. Vertical abutments occur where upwardly propagating tips interact to form triangular abutments and are a key mechanism forcing in the organisation of polygonal faults and growth of Master faults. Both abutment styles also impact the spatial distribution of displacement maxima. Polygonal fault tiers also show subtle spatial variablilty in orientation and linkage mechanisms that can be attributed to the distribution and magnitude of far field stresses as well as the early fault dimensions. This thesis also presents a primie facie case for diachronaity in polygonal fault growth driven by variations in sediment loading and branchline linkage complexity. Overall, this thesis describes and accounts for some key behaviours of incipient polygonal faults tiers.

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Hearn, David John. « Growth form evolution in Adenia (Passifloraceae) and a model of the evolution of succulence ». Diss., The University of Arizona, 2004. http://hdl.handle.net/10150/280706.

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The architecture of a plant is intimately tied to its fitness. Knowledge of the processes and patterns of growth form evolution can therefore contribute to a richer understanding of plant evolution. The genus Adenia (Passifloraceae) of ca. 100 species is an Old World lineage in which growth form radiated. I constructed a molecular phylogeny of the group, analyzed the stem and tuber anatomy of over half the species, and investigated patterns of growth form evolution in a phylogenetic context. I also described four new species and a new combination. Predictions based on evolutionary developmental models of growth form evolution were tested in Adenia, and one of them, the homeotic switch hypothesis, was tested throughout the eudicots. The switch hypothesis claims that the storage tissue of tubers and stems results from a common developmental origin. Phylogenetic analyses revealed that growth form transitions were frequent, and anatomical studies revealed traits that are associated with each growth form; moreover, traits are shared between tubers and succulent stems as predicted by the switch hypothesis. As expected, tuberous plants and succulents are also closely related across the eudicots. The switch hypothesis is substantiated in Adenia and the eudicots as a whole.

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Twite, Joanathan W. « Galaxy star formation and mass growth since z=3 ». Thesis, University of Nottingham, 2016. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.718862.

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In this thesis we investigate the evolution of galaxies since z = 3. There are several methods to measure the star formation rate (SFR) of galaxies, they all however have drawbacks. Several studies have investigated the SFR at high redshifts using SFR tracers that suffer from uncertainties, either from the tracer used, or from the uncertainties correcting for the effects of dust. We have new measurements of the Ha emission line for a sample of galaxies at =~1; Ha is a more accurate SFR-tracer than other commonly used tracers, but until now had been technically difficult to measure at : > 0.85. We investigate methods to correct these observations for dust and we use these measurements to investigate the relation between SFR, stellar mass and colour. We find that there is a drop in the fraction of massive (M, > 1011 M.) star-forming galaxies at = < 0.9 and that the fraction of all galaxies that are star-forming drops steadily and significantly with redder (U — B) colours. We find that the M„-SFR (galaxy main sequence, GMS) is flatter than previously measured and that for the most massive galaxies, star formation shuts off abruptly at =~1.

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McKinnon, John Motley. « Corrosion Damage Evolution of a Unidirectional Pit ». University of Akron / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=akron1463754286.

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12

Chua, Kian Hwa. « A study of multinational banking : its evolution and growth / ». Title page, contents and introduction only, 1985. http://web4.library.adelaide.edu.au/theses/09EC/09ecc5592.pdf.

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Malaikah, Khalid R. « Laplacian Growth : Interfacial Evolution in a Hele-Shaw Cell ». Ohio University / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1367417377.

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Grytsan, Andrii. « Computational model of abdominal aortic aneurysm inception and evolution ». Licentiate thesis, KTH, Biomekanik, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-142649.

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Incidence of abdominal aortic aneurysm (AAA) is increasing in the aging society of the western world. Development of AAA is mostly asymptomatic and is characterized by a bulge in the abdominal aorta. However, AAA may suddenly rupture, which results in an internal bleeding associated with a high mortality rate. Patients with AAA undergo regular screening until treatment indication. To date, statistical criteria are used to decide whether the risk of rupture exceeds the risk of intervention. Models of AAA development help to understand the disease progression and to yield patient-speciﬁc criterion for AAA rupture. Up to date, sophisticated models of AAA development exist. These models assume the abdominal aorta as a thin-walled structure, which saves the computational effort. This thesis aims at investigating the importance of employing a thick-walled model of the aorta. The effects on AAA development that cannot be captured with a thin-walled model are of interest. In Paper A, the thick-walled model of growth and remodeling of one layer of a AAA slice has been extended to a two-layered model. The parameter study has been performed to investigate the inﬂuence of mechanical properties and growth and remodeling (G&R) parameters of two individual layers on the gross mechanical response and G&R of the artery. It was concluded that the adventitia acts to protect the arterial wall against rupture even in pathological state. In Paper B, the model was extended to an organ level model of AAA development. Furthermore, the model was incorporated into a so-called Fluid-Solid-Growth (FSG) framework, where the AAA development is loosely coupled to the blood ﬂow conditions such as wall shear stress. One patient-speciﬁc geometry of the abdominal aorta is used to illustrate the model capabilities. A transmurally non-uniform distribution of the strains of individual arterial constituents was observed. In addition, an increased aneurysm tortuosity was observed in comparison to a thin-walled approach. These ﬁndings signify the importance of a thick-walled approach to model the aneurysm development. Finally, the proposed methodology provides a realistic basis to further explore the growth and remodeling of AAA on a patient-speciﬁc basis.

QC 20140311

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Oh, Joonyoung. « Numerical study of micro-scale damage evolution in time dependent fracture mechanics ». Connect to this title online, 2005. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1117645391.

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Thesis (Ph. D.)--Ohio State University, 2005.
Title from first page of PDF file. Document formatted into pages; contains xvi, 147 p.; also includes graphics Includes bibliographical references (p. 143-147). Available online via OhioLINK's ETD Center

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Parker, Reginald. « Kinetics and evolution of primary structures in step-growth polymerization ». Thesis, Georgia Institute of Technology, 1996. http://hdl.handle.net/1853/10996.

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Desierto, Desiree. « Growth, convergence and the co-evolution of institutions and technology ». Thesis, University of Nottingham, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.436727.

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Hu, Jianfeng. « Grain growth by Ordered Coalescence of crystallites in Ceramics : Grain Growth Mechanisms, Microstructure Evolution and Sintering ». Doctoral thesis, Stockholms universitet, Institutionen för material- och miljökemi (MMK), 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-88628.

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Grain growth and densification process play the two most crucial roles on the microstructure evolution and the achieved performances during sintering of ceramics. In this thesis, the grain growth of SrTiO3, BaTiO3-SrTiO3 solid solutions and Si3N4 ceramics during spark plasma sintering (SPS) were investigated by electron microscopy. SrTiO3 ceramics starting from nanopowders were fabricated by SPS. A novel grain growth mechanism was discovered and named as ordered coalescence (OC) of nanocrystals. This mechanism involved nanocrystals as building blocks and is distinguished from atomic layer epitaxial growth (AEG) in classical sintering theory. The results also revealed that the dominant grain growth mechanism can be changed by varying heating rates. Low rate (10°C/min) gives AEG, whereas high rates (≥ 50°C/min) yields three-dimensional coalescence of nanocrystals, i.e. OC. BaTiO3-SrTiO3 sintered bodies were made by SPS of BaTiO3 and SrTiO3 nanopowders mixtures. A novel Sr1-xBaxTiO3 “solid solution” with mosaic-like single crystal structure was manufactured by OC of the precursor crystallites. This reveals a new path for preparation of solid solution grains or composites. Si3N4 ceramics were prepared from α- or β-Si3N4 nanopowders at the same SPS conditions. The anisotropic OC of precipitated β-Si3N4 crystallites gives elongated β-Si3N4 grains at 1650°C using α-Si3N4 nanopowder. In contrast, AEG leads to the equi-axed β-Si3N4 grains using β-Si3N4 nanopowder. The metastable α- to β-Si3N4 phase transformation and OC accelerates anisotropic grain growth. Grain motions contribute to the densification process during pressureless sintered 3Y-ZrO2 (>87%TD) or SPS of SrTiO3 (>92%TD) ceramics. This extends the sintering range for active grain re-arrangement over that predicted by classical theory. In this thesis a new grain growth mechanism (OC) is proved by using SPS and nanopowders. By OC the microstructural evolution can be manipulated.

At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 2: Accepted. Paper 3: Submitted. Paper 4: Manuscript. Paper 7: Accepted.

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Biro, Daniel. « Towards intermediate complexity systems biology models of bacterial growth and evolution ». Thesis, Yeshiva University, 2018. http://pqdtopen.proquest.com/#viewpdf?dispub=10798623.

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Modern biological research is currently canalized into two main modes of research: detailed, mechanistic descriptions, or big data collection and statistical descriptions. The former has the advantage of being conceptually tractable and fitting into an existing scientific paradigm. However, these detailed descriptions can suffer from an inability to be understood in the larger context of biological phenomena. On the other hand, the big data approaches, while closer to being able to capture the full depth of biological complexity, are limited in their ability to impart conceptual understanding to researchers. We put forward examples of an intermediate approach. The goal of this approach is to develop models which can be understood as abstractions of biological phenomena, while simultaneously being conducive to modeling and computational approaches. Firstly, we attempt to examine the phenomenon of modularity. Modularity is an ubiquitous phenomenon in biological systems, but its etiology is poorly understood. It has been previously shown that organisms that evolved in environments with lower levels of stability tend to display more modular organization of their gene regulatory networks, although theoretical predictions have failed to account for this. We put forward a neutral evolutionary model, where we posit the process of genome expansion through gene duplications acts as a driver for the evolution of modularity. This process occurs through the duplication of regulatory elements alongside the duplication of a gene, causing sub-networks to be generated which are more tightly coupled internally than externally, which gives rise to a modular architecture. Finally, we also generate an experimental system by which we can verify our model of the evolution of modularity. Using a long term experimental evolution setup, we evolve E. coli under fluctuating temperature environments for 600 generations in order to test if there is a measurable increase in the modularity of the gene regulatory networks of the organisms. This data will also be used in the future to test other hypotheses related to evolution under fluctuating environments. The second such model is a computational model of the properties of bacterial growth as a function of temperature. We describe a model composed of a chain of enzyme like actions, where the output of each enzyme in the chain becomes the substrate of the following enzyme. Using well known temperature dependence curves for enzyme activity and no further assumptions, we are then able to replicate the salient properties of bacterial growth curves at varying temperatures, including lag time, carrying capacity, and growth rate. Lastly, we extend these models to attempt to describe the ability of cancer cells to alter their phenotypes in ways that would be impossible for normal cells. We term this model the phenotypically pliant cells model and show that it can encapsulate important aspects of cancer cell behavior.

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Yu, Hang Ph D. Massachusetts Institute of Technology. « Mechanisms for intrinsic stress evolution during and after polycrystalline film growth ». Thesis, Massachusetts Institute of Technology, 2013. http://hdl.handle.net/1721.1/81062.

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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2013.
Cataloged from PDF version of thesis.
Includes bibliographical references.
Growth of polycrystalline films involves poorly understood kinetic processes that occur far from equilibrium and lead to complex co-evolution of the surface, microstructure and intrinsic stress of the films. Here we present a comprehensive study consisting of in situ stress measurements, microstructure characterization, and analytical modeling for various polycrystalline systems. We find that in systems of high atomic mobility, the stress change after polycrystalline film growth can be attributed to a fast reversible surface process and a slow irreversible bulk process. The fast process is weakly dependent on temperature and is associated with changes in the shape of grain surfaces. The slow process is strongly dependent on temperature and is mostly associated with grain growth in the bulk of the film. We also discovered a turnaround phenomenon in which, under conditions of intermediate atomic mobility, the stress evolves from a tensile toward a compressive state, and then turns around to evolve toward a tensile state. This stress turnaround phenomenon is strongly dependent on the substrate temperature and deposition rate, and can be attributed to an increase of the grain size during film deposition. Grain growth during deposition not only leads to a tensile component of the intrinsic stress, but also changes the grain size dependence of the compressive component. The compressive component results from incorporation of excess adatoms in grain boundaries, and the magnitude of the compressive stress is controlled by a competition between adatom incorporation in 2D islands and incorporation at grain boundaries. We also investigated the effect of the angle of incidence of the flux of depositing atoms on stress and structure evolution during polycrystalline film growth. We find that as the angle of incidence increases, the coalescence thickness increases and the stress becomes less compressive or more tensile. We attribute these phenomena to the enhanced surface roughness, the shadowing effect, the steering effect and the presence of Ehrlich-Schwoebel barriers during oblique angle deposition. All these effects lead to suppression of the adatom-grain boundary incorporation process. Based on this thesis work, intrinsic stresses in polycrystalline films can be categorized into three types: Type I, the intermediate type and Type II. These behaviors are observed in systems of low, intermediate and high atomic mobility, respectively. Compressive stresses develop in Type II behavior and tensile stresses develop in Type I behavior. The transition of the stress behavior from Type I, to the intermediate type and to Type II is continuous and can be achieved by adjusting deposition conditions. Whether the post-coalescence stress is tensile, or compressive, or evolving from compressive to tensile depends on the homologous temperature, the deposition rate and the angle of the incidence of the flux of depositing atoms.
by Hang Yu.
Ph.D.

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Seel, Steven Craig 1972. « Stress and structure evolution during Volmer-Weber growth of thin films ». Thesis, Massachusetts Institute of Technology, 2002. http://hdl.handle.net/1721.1/29912.

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Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2002.
Includes bibliographical references (v. 2, leaves 283-294).
To investigate stress evolution during film deposition, a novel electrical technique for in situ thin film stress measurements was developed utilizing piezoresistive silicon microcantilevers, or piezocantilevers. In addition to the thin film stress measurements of Cu made with the piezocantilevers, our collaborators at Sandia National Laboratories have studied thin film growth stresses for Al, Ag, and amorphous Ge (a-Ge) films measured using conventional laser deflectometery. A computer simulation of thin film formation by the Volmer-Weber mechanism was developed to model the nucleation and growth of individual islands that impinge and coalesce to form a continuous film. By including a size-dependent lattice contraction in pre-coalescence islands, the simulation can be used to qualitatively reproduce the measured compressive stress behavior of Al at low film thicknesses. In contrast to Al films that support stress from the very onset of deposition, Ag films exhibit no measurable stress until larger film thickness are achieved. This difference in behavior was attributed to shear occurring at the Ag-SiO2 interface, which is suppressed at the much stronger Al-SiO2 interface. Tensile stress generation resulting from island coalescence was modeled analytically and by finite element methods (FEM) as the energetic balance between interfacial energy reduction and strain energy generation resulting from grain boundary formation. The magnitude of the island-coalescence stress calculated using FEM was found to decrease dramatically with decreasing island-substrate contact angle.
(cont.) Using the contact-angle-dependent FEM calculations of island-coalescence stress, simulations closely matched the stress-thickness measurements of Al, by assuming perfect island-substrate traction, and of Ag, by assuming partial island-substrate sliding, over the range of thicknesses prior to film continuity. The compressive stress evolution during deposition of continuous films and the stress behavior during interrupts of film growth was modeled in terms of a non-equilibrium surface morphology that develops during deposition. For the resulting non-equilibrium grain shapes, the in-plane compressive stress resulting from excess surface stress was calculated using FEM. Model predictions are consistent with observed decreasing compressive stress-thickness with increasing film thickness observed experimentally for Cu and a-Ge, as well as the reversible tensile rise behavior observed during growth interrupts of Cu.
by Steven Craig Seel.
Ph.D.

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Bolter, Debra R. « Anatomical growth patterns in colobine monkeys and implications for primate evolution / ». Diss., Digital Dissertations Database. Restricted to UC campuses, 2004. http://uclibs.org/PID/11984.

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Roy, Varun Kumar. « Studying urbanism : the spatial, physical and bodily manifestations in the administrative towns of provincial Bengal 1957- c.1857 ». Thesis, University of North Bengal, 2020. http://ir.nbu.ac.in/handle/123456789/4376.

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Grytsan, Andrii. « Abdominal aortic aneurysm inception and evolution - A computational model ». Doctoral thesis, KTH, Biomekanik, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-197289.

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Abdominal aortic aneurysm (AAA) is characterized by a bulge in the abdominal aorta. AAA development is mostly asymptomatic, but such a bulge may suddenly rupture, which is associated with a high mortality rate. Unfortunately, there is no medication that can prevent AAA from expanding or rupturing. Therefore, patients with detected AAA are monitored until treatment indication, such as maximum AAA diameter of 55 mm or expansion rate of 1 cm/year. Models of AAA development may help to understand the disease progression and to inform decision-making on a patient-specific basis. AAA growth and remodeling (G&R) models are rather complex, and before the challenge is undertaken, sound clinical validation is required. In Paper A, an existing thick-walled model of growth and remodeling of one layer of an AAA slice has been extended to a two-layered model, which better reflects the layered structure of the vessel wall. A parameter study was performed to investigate the influence of mechanical properties and G&R parameters of such a model on the aneurysm growth. In Paper B, the model from Paper A was extended to an organ level model of AAA growth. Furthermore, the model was incorporated into a Fluid-Solid-Growth (FSG) framework. A patient-specific geometry of the abdominal aorta is used to illustrate the model capabilities. In Paper C, the evolution of the patient-specific biomechanical characteristics of the AAA was investigated. Four patients with five to eight Computed Tomography-Angiography (CT-A) scans at different time points were analyzed. Several non-trivial statistical correlations were found between the analyzed parameters. In Paper D, the effect of different growth kinematics on AAA growth was investigated. The transverse isotropic in-thickness growth was the most suitable AAA growth assumption, while fully isotropic growth and transverse isotropic in-plane growth produced unrealistic results. In addition, modeling of the tissue volume change improved the wall thickness prediction, but still overestimated thinning of the wall during aneurysm expansion.
Bukaortaaneurysm (AAA) kännetecknas av en utbuktning hos aortaväggen i buken. Tillväxt av en AAA är oftast asymtomatisk, men en sådan utbuktning kan plö̈tsligt brista, vilket har hög dödlighet. Tyvärr finns det inga mediciner som kan förhindra AAA från att expandera eller brista. Patienter med upptä̈ckt AAA hålls därför under uppsikt tills operationskrav är uppnådda, såsom maximal AAA-diameter på 55 mm eller expansionstakt på 1 cm/år. Modeller för AAA-tillväxt kan bidra till att öka förståelsen för sjukdomsförloppet och till att förbättra beslutsunderlaget på en patientspecifik basis. AAA modeller för tillväxt och strukturförändring (G&R) är ganska komplicerade och innan man tar sig an denna utmaning krävs de god klinisk validering. I Artikel A har en befintlig tjockväggig modell för tillväxt av ett skikt av en AAA-skiva utö̈kats till en två-skiktsmodell. Denna modell återspeglar bättre den skiktade strukturen hos kärlväggen. Genom en parameterstudie undersö̈ktes påverkan av mekaniska egenskaper och G&R-parametrar hos en sådan modell för AAA-tillväxt. I Artikel B utvidgades modellen från Artikel A till en organnivå-modell för AAA-tillväxt. Vidare inkorporerades modellen i ett “Fluid–Solid–Growth” (FSG) ramverk. En patientspecifik geometri hos bukaortan användes för att illustrera möjligheterna med modellen. I Artikel C undersöktes utvecklingen av patientspecifika biomekaniska egenskaper hos AAA. Fyra patienter som skannats fem till åtta gånger med “Computed Tomography-Angiography” (CT-A) vid olika tillfällen analyserades. Flera icke triviala statistiska samband konstaterades mellan de analyserade parametrarna. I Artikel D undersöktes effekten av olika tillväxt-kinematik för AAA tillväxt. En modell med transversellt-isotrop-i-tjockleken-tillväxt var den bäst lämpade för AAA tillväxt, medans antagandet om fullt-isotrop-tillväxt och transversellt-isotrop-i-planet-tillväxt producerade orimliga resultat. Dessutom gav modellering av vävnadsvolymsförändring ett förbättrat väggtjockleks resultat men en fortsatt överskattning av väggförtunningen under AAA-expansionen.

QC 20161201

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Wang, Yingshuo. « Network Econometrics and the Evolution of Transport Systems ». Thesis, TransportLab, 2021. https://hdl.handle.net/2123/27158.

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This thesis systematically develops a network correlation matrix that explicitly distinguishes competitive and complementary link pairs in transportation networks. Embedding the matrix in network econometric analysis, this thesis consolidates that incorporating representative spatial information with a network perspective is capable of improving the performance of traffic forecasting models. The method is validated in the context of a real-world transport system rather than within simulated settings adopted by previous research. An Autoregressive-Distributed Lag (ARDL) model is specified, and reveals that the combination of correlation strength and magnitude of lagged flow change on correlated links is an significant predictor of future traffic flow. This thesis innovatively extends network econometric methods, previously exclusively used for traffic flow forecasting, to the domain of network structure prediction by specifying a logit model. It finds that complementary and competitive links play distinct roles in shaping the network structure. If positively correlated, a link is more likely to undergo the same structural change influential links underwent previously where the influence is measured by a combination of correlation strength and link importance, reflected by historical flow level. Additionally, this thesis establishes a digitized database of the Sydney tramway system, providing a complete set of data for more research.

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Lv, Qiming. « Stochastic modelling with applications to growth, evolution and competition in random environments ». Thesis, University of York, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.488740.

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Hampton, Samuel Job. « Growth, Structure and Evolution the Lyttelton Volcanic Complex, Banks Peninsula, New Zealand ». Thesis, University of Canterbury. Geological Sciences, 2010. http://hdl.handle.net/10092/4117.

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The Lyttelton Volcanic Complex, north-western Banks Peninsula, New Zealand, is comprised of five overlapping volcanic cones. Two magma systems are postulated to have fed Banks Peninsula’s basaltic intraplate volcanism, with simultaneous volcanism occurring in both the north-western and south-eastern regions of Banks Peninsula, to form Lyttelton and Akaroa Volcanic Complexes respectively. The elongate form of Banks Peninsula is postulated to relate to the upward constraining of magmatism in a north-west / south-east fault bounded zone. The Lyttelton Volcanic Complex resulted from the development of a pull-apart basin, with a number of releasing bend faults, controlling the location of eruptive sites. Cone structure further influenced the pathway magma propagated, with new eruptive sites developing on the un-buttressed flanks, resulting in the eruption and formation of a new cone, or as further cone growth recorded as an eruptive package. Each cone formed through constructional or eruptive phases, termed an eruptive package. Eruptive packages commonly terminate with a rubbly a’a to blocky lava flow, identified through stratigraphic relationships, lava flow trends and flow types, a related dyking regime, and radial erosional features (i.e. ridges and valleys). Within the overall evolving geochemical trend of the Lyttelton Volcanic Complex, are cyclic eruptive phases, intrinsically linked to eruptive packages. Within an eruptive package, crystal content fluctuates, but there is a common trend of increasing feldspar content, with peak levels corresponding to a blocky lava flow horizon, indicating the role of increased crystalinity and lava flow rheology. Cyclic eruptive phases relate to discreet magma batches within the higher levels of the edifice, with crystal content increasing as each magma batch evolves, limiting the ability of the volcanic system, over time, to erupt. Evolving magmas resulted in explosive eruptions following effusive eruptives, and / or result in the intrusion of hypabyssal features such as dykes and domes, of more evolved compositions (i.e. trachyte). Each eruptive package hosts a radial dyke swarm, reflecting the stress state of a shallow level magma chamber or a newly developed stress field due to gravitational relaxation in the newly constructed edifice, at the time of emplacement. Two distinct erosional structures are modelled; radial valleys and cone-controlled valleys. Radial valleys reflect radial erosion about a cone’s summit, while cone-controlled valleys are regions where eruptive packages and cones from different centres meet, allowing stream development. Interbedded epiclastic deposits within the Lyttelton lava flow sequences indicate volcanic degradation during volcanic activity. As degradation of the volcanic complex progressed, summit regions coalesced, later becoming unidirectional breached, increasing the area of the drainage basin and thus the potential to erode and transport extensive amounts of material away, ultimately forming Lyttelton Harbour, Gebbies Pass, and the infilled Mt Herbert region. Epiclastic deposits on the south-eastern side of Lyttelton Harbour indicate a paleo-valley system (paleo-Lyttelton Harbour) existed prior to 8.1 Ma, while the morphology of the Lyttelton Volcanic Complex directed the eruptive sites, style and resultant morphology of the proceeding volcanic groups.

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Wong, Mak Yin-yuk Vanessa, et 黃麥燕玉. « The evolution and revolution of a rapid growth firm in Hong Kong ». Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1987. http://hub.hku.hk/bib/B31263951.

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Lioupis, Alexandros. « Studies on non-primate growth hormones : molecular evolution and structure-function relationships ». Thesis, University of Sussex, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.263869.

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Kuo, Eva Grotkopp. « Genome size evolution, seedling relative growth rate, and invasiveness in pines (Pinus) / ». For electronic version search Digital dissertations database. Restricted to UC campuses. Access is free to UC campus dissertations, 2003. http://uclibs.org/PID/11984.

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Xue, Xia. « Genomics and Transcriptomics of Antarctic Nematodes Reveal Drivers of Life History Evolution and Genome Evolution ». BYU ScholarsArchive, 2018. https://scholarsarchive.byu.edu/etd/7422.

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Elemental stoichiometry defines a critical understanding of the relationship between nutrient availability and usage throughout different levels of the biological community. We found there is a link between available phosphorus (P), cellular phosphorus, and nematode development as postulated by the growth rate hypothesis (GRH). I predicted that in a P-poor environment, cellular RNA concentrations would be lower than they are in P-rich environment, and thus the 18s rRNA expression level will have reduced. To most efficiently regulate the uptake of limited P, I predicted that nematodes in P-poor environments would decrease the number of copies of the 18s rRNA gene in their genome. I measured life history traits as well as rRNA gene expression and gene copy number. We found that elemental stoichiometry predicts evolutionary changes consistent with the Growth Rate Hypothesis. We sequenced and assembled a draft genome of P. murrayi. Although we expected to find genes responsible for stress tolerance, we hypothesized that in response to strong selection pressure associated with living in a simplified ecosystem, over time the genome of P. murrayi should have undergone significant decay (gene loss) relative to species in ecosystems structured more strongly by biotic interactions. We found significantly fewer genes in P. murrayi. To compare patterns of gene expression between two highly divergent Antarctic nematode species, we sequenced and assembled the transcriptomes of S. lindsayae and P. murrayi. Under laboratory conditions at 4˚C, S. lindsayae had significantly lower rates of gene expression but expressed a significantly larger number of genes. We speculate that the differences in gene expression are correlated with life history traits (developmental rates) while the differences in the number of genes expressed can be explained by their different genetic systems (S. lindsayae is amphimictic, P. murrayi is parthenogenic) and the soil environments to which they are adapted. Since we previously showed that differences in available P content can influence the evolution of gene expression via gene copy number, and that this ultimately influences growth rate, we wondered how much of this response is driven by genetics versus how strongly these patterns are driven by temperature. To better understand this, we maintained wild type populations of P. murrayi in P-rich and P-poor conditions at 5˚C, 10˚C and 15˚C in the laboratory for over 40 generations and sequenced the transcriptomes prepared from each treatment group. We found that nutrient levels played an important role in gene expression when the temperature is optimal for P. murrayi culturing and that temperature is more important in gene expression when the available P is limited. This work underscores the utility of using principles of elemental stoichiometry coupled with genomic and transcriptomics research tools to make and test predictions about life history evolution. The results of my work also inform inferences about the ways in which nutrient availability also drives the organization of trophic interactions and ultimately ecosystems.

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Wolfe, Malory Mae. « Salt Adaptation for Enhanced Growth and Sucrose Production in Cyanobacteria ». Miami University / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=miami1626360418183729.

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Thorén, Kent. « Realizing a fast growth strategy : a case study of the evolution of management control systems in a fast growing firm / ». Stockholm : Institutionen för industriell ekonomi och organisation, Tekniska högsk. : Arvinius, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-1812.

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Williams, Devin N. « The Association of Size Variation in the Dental Arch to Third Molar Agenesis for a Modern Population ». Scholar Commons, 2018. http://scholarcommons.usf.edu/etd/7247.

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The frequency with which individuals do not develop their third molars, or wisdom teeth, is increasing worldwide. This current topic of human evolution is relevant to the research of anthropologists, geneticists, dentists, and other researchers involved in the study of human dentition. Many explanations have been offered to account for the prevalence of molar agenesis including, evolutionary, environmental, and genetic theories. The purpose of this research project is to determine the frequency of third molar agenesis and investigate the relationship between third molar agenesis and maxillomandibular jaw dimensions in a sample of orthodontic patients. This research tests the hypotheses that: H1: Individuals with agenesis of third molars will be significantly different in maxillomandibular dimensions than individuals without agenesis, H2: The agenesis of maxillary third molars is associated with the anteroposterior dimensions of the maxilla, and H3: The agenesis of mandibular third molars is not associated with the anteroposterior dimensions of the mandible. Therefore, the null hypothesis for this research is H0: An individual’s sex and the presence/absence of the third molar are independent. The sample for this research project includes 543 individuals from the University of New Mexico’s Maxwell Museum of Anthropology Orthodontics Case File System. This study examines panoramic radiographs of the dentition for each individual to ascertain whether any of the third molars was congenitally absent, and records the cephalometric measurements for each case for statistical analysis. This study uses descriptive statistics, crosstabulation analysis, chi-square tests, non-parametric Kruskal-Wallis tests, and logistic regression analysis to investigate any associations between third molar agenesis and maxillomandibular jaw dimensions. The results show that Native Americans (9.2%), Hispanics (8.46%), and European Americans (8.37%) have a higher frequency of third molar agenesis than African Americans (0.17%) and Asians (0.17%). This finding is consistent with the published body of work on third molar agenesis, in spite of the small sample sizes for diverse populations. There is a significant difference in the number of molars missing among groups. For the present study, based on crosstabulation analysis, most individuals are missing two molars (34.9%), followed by one absent (31.7%), a lack of four molars (25.3%), and finally a lack of 3 molars (7.9%). Individuals with third molar agenesis are nearly twice as likely to be missing a molar from the mandible (62.8%) than the maxilla (36.9%). This study uses crosstabulation analysis, chi-square analysis, non-parametric Kruskal-Wallis tests, and logistic regression analysis to assess the association between third molar agenesis and measurements of the dental arcade. This study did not find an association between an individual’s maxillomandibular dimensions and third molar agenesis. Therefore, this study did not find support for the hypothesis that individuals with third molar agenesis would have smaller maxillomandibular dimensions than individuals without agenesis. Based on the findings of this study, an association between the size of an individual’s mouth and third molar agenesis does not exist in the sample analyzed. Third molar agenesis is not occurring due to a lack of room in the mouth, but possibly results from heredity. Therefore, it may be more likely that genetic variation influences third molar agenesis, rather than an evolutionary change in diet.

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黃詠嫻 et Wing-han Wong. « The initial growth and evolution of microstructure of YBa2Cu3O7-8 thinand ultrathin films ». Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1995. http://hub.hku.hk/bib/B31213789.

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Vinayak, Aasis. « Towards a better understanding of the evolution of senescence, apoptosis and tumour growth ». Thesis, University of Surrey, 2015. http://epubs.surrey.ac.uk/809347/.

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Senescence (ageing) and apoptosis (programmed cell death) are phenomena that have troubled theoreticians and experimentalists. Previous research showed that the mortality curve of the yeast population followed the Gompertz-Makeham equation. We develop a generalised theoretical model which shows that the mortality of the organism can be expressed as a function of Ageing Factors such as ERCs. We use this idea to explain why senescence leads to apoptosis. Antagonistic pleiotropy and disposable soma theory suggest that senescence (and accordingly apoptosis) is a `side effect'. Although the altruistic benefits of apoptosis have been suggested before, we are attempting to show that in a resource-restricted environment, apoptosis can be a strategic choice. We show that the interactions between apoptotic and non-apoptotic organisms can be modelled using game theory and differential equations. We find that switching to apoptotic mode gives the organism an advantage over the non-apoptotic organisms in a resource-restricted environment. Mathematical analysis indicates that apoptosis is a stable strategy provided the conditions remain the same. We also find that one apoptotic organism can invade a population of non-apoptotic organisms. This begs the question - why do tumours (which are non-apoptotic) occur if apoptosis is the best strategy? We show that apoptosis and angiogensis play a significant role in the development of tumours. We studied the effects of these two parameters on the dynamics of tumour and apoptotic populations. We find that the mixed strategy of avoidance of apoptosis and angiogenesis gives neoplasms an advantage over apoptotic organisms in certain conditions. Accordingly, the tumour organisms can invade apoptotic tissues. We also find that this strategy is not beneficial in the long-term.

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Griffin, Christopher T. « The evolution of intraspecific variation, growth, and body size in early theropod dinosaurs ». Thesis, Virginia Tech, 2016. http://hdl.handle.net/10919/73682.

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Understanding the changes undergone during the life of an organism is often crucial to properly interpreting the evolutionary history of a group. For extinct organisms, this process can only be directly studied through growth series of fossils representing individuals at different stages of maturity. The growth patterns of the earliest dinosaurs (230–190 million years ago), in particular the morphological changes undergone during the life history of an individual (i.e., ontogeny) is poorly understood. To tackle this problem, I studied the changes undergone during growth of two early theropod dinosaurs, Coelophysis bauri and Megapnosaurus rhodesiensis. To reconstruct the growth of these dinosaurs I used ontogenetic sequence analysis (OSA). I found that, unlike living birds, early dinosaurs possessed an extremely high amount of intraspecific variation in growth. This variation had been previously interpreted as sexual difference; however, I found no evidence of this. Because this variation is widespread among early dinosaurs and their relatives, I hypothesize that this is the ancestral condition of dinosaurian growth, and that this was lost along the evolution to birds. These ontogenetic events are conserved through evolution, and I used this to assess the maturity of large Triassic theropods: I suggest that all known large-bodied Triassic theropods were still growing rapidly at death, and that the maximum body size of Triassic theropods was higher than previously supposed. Theropods were large before the end Triassic mass extinction, unlike what has been previously hypothesized.
Master of Science

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Abadias, G., L. E. Koutsokeras, P. A. Patsalas, W. Leroy, D. Depla, S. V. Zlotsi et V. V. Uglov. « In situ stress evolution during growth of transition metal nitride films and nanocomposites ». Thesis, Видавництво СумДУ, 2011. http://essuir.sumdu.edu.ua/handle/123456789/20742.

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The issue of stress evolution during growth of hard transition metal nitride (TMN) based coatings is of vital importance to understand origin of intrinsic stress development and to control stress level in order to avoid mechanical failure of coated components and devices. By using in situ and real-time wafer curvature measurements based on a multiple- beam optical stress sensor (MOSS), basic insights on the atomistic mechanisms at the origin of stress development and stress relaxation can be obtained. In the present paper, a review of recent advances on stress development during reactive magnetron sputter-deposition of binary TMN films (TiN, ZrN, TaN) as wells as ternary systems (TiZrN, TiTaN) will be presented. The influence of growth energetics on the build-up of compressive stress will be addressed. A correlation between stress, texture and film morphology is demonstrated. Finally, illustration will be given for quaternary TiZrAlN nanocomposites. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/20742

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CARPENTER, WILLIAM JOSEPH. « Dust Grain Growth and Disk Evolution of a Set of Young Stellar Objects ». University of Cincinnati / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1204639846.

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Wilson, John O. S. « Firm size and growth and the evolution of market structure in European banking ». Thesis, Bangor University, 1999. https://research.bangor.ac.uk/portal/en/theses/firm-size-and-growth-and-the-evolution-of-market-structure-in-european-banking(9447e95a-4c1f-4a35-9df9-f035ecfff6c6).html.

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This thesis examines the size-growth relationship for banking and manufacturing firms. In particular it tests the Law of Proportionate Effect (LPE) which suggests that there is no relationship between firm size and growth. Tests of the LPE are carried out for eight European banking markets (Belgium, Denmark, France, Germany, Italy, Netherlands, Spain and the United Kingdom) and for three bank types (commercial, co-operative and savings) over the period 1990 to 1994. Employing three measures of size (total assets, equity and off balance sheet business) models are estimated that test for size effects on growth, and the influences of previous growth, bank type and country membership. In the majority of cases, bank growth is independent of bank size, so the LPE holds. However, small banks grew faster than their larger counterparts (in terms of assets and equity) in France, Italy and Spain. The LPE is also investigated for a sample of European manufacturing firms drawn from five countries and eleven industry groups. In contrast to the banking industry there is less evidence that the LPE holds. In most cases small firms grew proportionately faster than their larger counterparts. Using stochastic simulation techniques, the effects of firm growth, entry, exit and merger activity on the evolution of bank sizes and market concentration is examined. Using a simulated industry in which the LPE holds as the benchmark, the implications of various alternative assumptions regarding bank growth were examined. Superimposition of entry leads to a lower mean bank size and lower levels of concentration. Exit leads to higher mean bank size and increased concentration. Mergers lead to increases in mean bank size and concentration in all simulated industries. Using the simulations methodology, hypothetical projections as to the future structure of the banking markets in France, Germany, Italy, Spain and the UK are carried out. Overall, the simulations suggest that bank numbers are likely to decrease in all countries. The market shares of the largest banks are also projected to decline in all countries with the exception of the UK.

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Rujopakarn, W., K. Nyland, G. H. Rieke, G. Barro, D. Elbaz, R. J. Ivison, P. Jagannathan, J. D. Silverman, V. Smolčić et T. Wang. « Cospatial Star Formation and Supermassive Black Hole Growth in z ∼ 3 Galaxies : Evidence for In Situ Co-evolution ». IOP PUBLISHING LTD, 2018. http://hdl.handle.net/10150/627111.

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We present a sub-kiloparsec localization of the sites of supermassive black hole (SMBH) growth in three active galactic nuclei (AGNs) at z similar to 3 in relation to the regions of intense star formation in their hosts. These AGNs are selected from Karl G. Jansky Very Large Array (VLA) and Atacama Large Millimeter/submillimeter Array (ALMA) observations in the Hubble Ultra-Deep Field and COSMOS, with the centimetric radio emission tracing both star formation and AGN, and the sub/millimeter emission by dust tracing nearly pure star formation. We require radio emission to be >= 5 x more luminous than the level associated with the sub/millimeter star formation to ensure that the radio emission is AGN-dominated, thereby allowing localization of the AGN and star formation independently. In all three galaxies, the AGNs are located within the compact regions of gas-rich, heavily obscured, intense nuclear star formation, with R-e = 0.4-1.1 kpc and average star formation rates of similar or equal to 100-1200 M(circle dot)yr(-1). If the current episode of star formation continues at such a rate over the stellar mass doubling time of their hosts, similar or equal to 0.2 Gyr, the newly formed stellar mass will be of the order of 10(11)M(circle dot). within the central kiloparsec region, concurrently and cospatially with significant growth of the SMBH. This is consistent with a picture of in situ galactic bulge and SMBH formation. This work demonstrates the unique complementarity of VLA and ALMA observations to unambiguously pinpoint the locations of AGNs and star formation down to similar or equal to 30 mas, corresponding to; 230 pc at z = 3.

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Atlee, David W. « A Multiwavelength Comparison of the Growth of Supermassive Black Holes and Their Hosts in Galaxy Clusters ». The Ohio State University, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=osu1313508144.

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Ellens, Elizabeth Rose. « Evolution of the Growth Hormone Receptor : Insights Into the Molecular Basis of the Physiologically Pleiotropic Nature of the Growth Hormone Receptor ». Thesis, North Dakota State University, 2014. https://hdl.handle.net/10365/26654.

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One of the oldest, extant, lineages of vertebrates, the sea lamprey, was used to clarify the evolutionary origin and divergence of the growth hormone receptor (GHR) family. A single, full-length, cDNA, and a second, partial, cDNA were identified and shown to encode proteins that share amino acid identity with GHRs and prolactin receptors (PRLR s) previously identified. The complexity of the dynamic signaling system, with special emphasis on this system in fish and in the context of the evolution of this system, is discussed in the first chapter. The second chapter integrates the new insights gained by these studies. Included is a newly proposed phylogenetic analysis and revised nomenclature-system for vertebrate GHRs that better represents the evolutionary history of the receptor family. The molecular evolution of the receptors is, furthermore, highlighted as the backdrop for the continued discussion regarding how the GH-family of hormones exhibit such coordinated and pleiotropic actions.

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Juneau, Stephanie. « Connecting Galaxy and Supermassive Black Hole Growth During the Last 8 Billion Years ». Diss., The University of Arizona, 2011. http://hdl.handle.net/10150/202989.

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It has become increasingly clear that a complete picture of galaxy evolution requires a better understanding of the role of Active Galactic Nuclei (AGN). In particular, they could be responsible for regulating star formation and galaxy growth via feedback processes. There are also competing views about the main modes of stellar growth and supermassive black hole growth in galaxies that need to be resolved. With high infrared luminosities (thus star formation rates) and a frequent occurrence of AGN, galaxies selected in the far-infrared wavebands form an ideal sample to search for a connection between AGN and star formation. The first part of this thesis contains a detailed analysis of the molecular gas properties of nearby infrared luminous and ultraluminous infrared galaxies (LIRGs and ULIRGs). We find that the enhanced molecular gas density in the most IR-luminous systems can be explained by major galaxy mergers, and that AGN are more likely to reside in higher-density systems. While the frequent concurrence of AGN and galaxy mergers in ULIRGs was already established, this work provides a coherent framework that explains trends observed with five molecular gas tracers with a broad range of critical densities, and a comparison with simulations that reproduce observed molecular line ratios without invoking AGN-induced chemistry. The second part of the thesis presents an analysis of the AGN content of intermediate redshift galaxies (0.3

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Fuller, Christopher L. « Growth and stoichiometry of diptera in response to changes in resource stoichiometry ». Thesis, University of Central Arkansas, 2014. http://pqdtopen.proquest.com/#viewpdf?dispub=1549934.

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Microbial biofilms on leaf litter can assimilate nutrients, thus altering the elemental composition (i.e. stoichiometric composition) of detritus. Aquatic macroinvertebrates consuming stoichiometrically-altered detritus may increase, decrease, or not change growth rates depending upon their body stoichiometry. Invertebrates with high body phosphorus (P) can allocate more P to rRNA, increasing protein production and growth. Thus, if diet nutrient limitation is alleviated, high P invertebrates are expected to increase growth rates. Conversely, low P invertebrates might not respond or decrease growth rates, due to the metabolic costs of eliminating excess nutrients. Diptera from two families were used in growth studies and fed either maple or oak leaves with different levels of carbon:phosphorus (C:P) to determine if diet P influenced growth rates and body stoichiometry of these high P organisms.

Tipula abdominalis from the family Tipulidae, were hypothesized to increase growth and consumption rates, and decrease body C:P as diet C:P decreased. It was also hypothesized that the proportion of consumed material composed of a particular element used in growth would increase (GGE), and that the diet ratio at which neither C or P is limiting, and at which maximum growth would occur, would decrease as diet C:P decreased (TERC:P). It was observed that T. abdominalis growth and consumption varied based on leaf type and elemental composition. Tipula abdominalis fed oak had high growth (5.4% day-1) and consumption (1.98mg mg tipulid-1 day-1) compared to maple diets, while individuals fed maple increased growth (2.6 to 5.0% day-1) and consumption (1.1 to 2.1mg mg tipulid-1 day-1) across treatments as maple C:P decreased. Tipula abdominalis were overall homeostatic in body stoichiometry. Contrary to expectations, GGEs decreased as diet C:P decreased, maintaining stoichiometric homeostasis. Also, current TER calculations were not representative of observed growth rates. Thus, results indicate that leaf stoichiometry and leaf type interact to influence growth rates.

Three genera of Chironomidae (Chironomus, Polypedilum, Micropsectra ) were fed a gradient of diet C:P to determine if there are differences in taxon-specific growth responses to changes in diet stoichiometry. It was hypothesized that genera with higher body P would increase growth more than genera with lower body P, and that body P in high P genera would increase as they consumed more dietary P. The three genera had different growth responses to decreased diet C:P that did not appear to be influenced by organism body stoichiometry or diet stoichiometry. Chironomus fed maple and oak and Micropsectra fed maple had similar growth rates (17.5% day^-1), while having significantly different body C:P, 141 and 249 for Chironomus fed oak and maple, respectively, and 359 for Micropsectra fed maple. Despite similarities in diet C:P ranges (1000 to 8000), Chironomus and Polypedilum had different growth responses: Chironomus had high growth, while Polypedilum fed maple did not grow and lost mass (- 4.8% day^-1), and Polypedilum fed oak exhibited relatively low growth rates (5.9% day^-1). Leaf type and genus identity appear to be important factors in determining growth response. However, most Dipterans in this study either increased growth or had no response to dietary P enrichment. Understanding how organism genus identity interacts with leaf type and leaf stoichiometry to influence growth rates will allow more accurate predictions of community changes in nutrient enriched systems.

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Ker, Louise Moira. « Radio AGN evolution with low frequency radio surveys ». Thesis, University of Edinburgh, 2013. http://hdl.handle.net/1842/7616.

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Supermassive black holes are leading candidates for the regulation of galaxy growth and evolution over cosmic time, via ‘feedback’ processes, whereby outflows from the Active Galactic Nuclei (AGN) halt star formation within the galaxy. AGN feedback is generally thought to occur in two modes, high-excitation (HERG, or ‘quasar-mode’) and low-excitation (LERG or ’radio-mode’) each having a different effect on the host galaxy. LERGs curtail the growth of the most massive galaxies, whereas HERGs are thought to be activated by mergers/interactions, switching off star formation at high redshift. A critical problem in current extragalactic astrophysics lies in understanding the precise physical mechanisms by which these feedback processes operate, and how they evolve over cosmic time. Radio-loud AGN are an essential tool for studying major feedback mechanisms, as they are found within the largest ellipticals, and hence are beacons for the most massive black holes across the bulk of cosmic time. In this thesis I develop and study existing complete radio samples with extensive new multi-wavelength data in the radio, optical and infrared, aiming to investigate the evolution of AGN feedback modes, and methods to locate and study such systems at the very highest redshifts. This will serve to inform further studies of radio-AGN planned with next generation radio instruments such as the LOw Frequency ARray (LOFAR). Very few radio-loud AGN systems are currently known at high redshifts, and the effectiveness of traditional high redshift selection techniques, such as selection based on steep spectral index, have not been well quantified. A purely evidence-based approach to determining the efficiency of various high redshift selection techniques is presented, using nine highly spectroscopically complete radio samples; although weak correlations are confirmed between spectral index and linear size and redshift, selection first of infrared-faint radio sources remains by far the most efficient method of selecting high-z radio galaxies from complete samples. Radio spectral curvature in four of the complete samples is analysed and the effect of radio spectral shape on the measurement of the radio luminosity function (RLF) of steep-spectrum radio sources is investigated. Below z=1, curvature has negligible effect on the measurement of the RLF, however at higher redshifts, where source numbers are low, the shape of the radio spectrum should be taken into account, as individual source luminosities can change up to 0.1-0.2 dex, and this can in some cases introduce errors in space density measurements of up to a factor of 2-3 where source numbers are low. Building upon these samples, the very first independent determinations of the separate RLFs for high and low excitation radio sources across the bulk of cosmic time are made, out to z=1. Here it is shown that HERGs show very clear signs of strong evolution, in line with theoretical predictions. LERGs also show some very weak evolution with redshift, showing increases in space density of typically around a factor of 2. These measurements are also used to estimate the contribution of LERGs, which typically show weak or no emission lines to the ‘missing redshift’ population, which are sources within the complete samples not identifiable spectroscopically. Complementary to this, a pilot study is presented in selecting ‘missing redshift’ sources which are classed as infra-red faint (IFRS), which show no optical or near-IR identification, and are compact in the radio. Follow up spectroscopy on these candidate high z sources detected no line emission. Finally, work carried out towards the testing and commissioning of the new LOFAR telescope is presented. The findings from this thesis will serve to both streamline and inform high redshift radio-AGN searches and studies planned to be carried out with LOFAR and other multi-wavelength complementary surveys in the near future, and help to open up an as yet unexplored epoch in radio-AGN formation and evolution.

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Sonnweber-Ribic, Petra [Verfasser]. « Grain growth and texture evolution in copper thin films / vorgelegt von Petra Sonnweber-Ribic ». Stuttgart : Max-Planck-Inst. für Metallforschung, 2010. http://d-nb.info/1012645266/34.

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Jang, Ha Won. « Phases of capital accumulation in Korea and evolution of government growth strategy, 1963-1990 ». Thesis, University of Oxford, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.307330.

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Ma, Yingxiao. « Experimental investigation and computer simulation of grain growth and microstructur evolution in 2D polycristals / ». Dortmund : Wulff, 2008. http://bvbr.bib-bvb.de:8991/F?func=service&doc_library=BVB01&doc_number=017070274&line_number=0001&func_code=DB_RECORDS&service_type=MEDIA.

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Wong, Wing-han. « The initial growth and evolution of microstructure of YBa2Cu3O7-8 thin and ultrathin films / ». Hong Kong : University of Hong Kong, 1995. http://sunzi.lib.hku.hk/hkuto/record.jsp?B1748957X.

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Thèses sur le sujet « Growth and evolution »

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