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McDaniel, Brent. "Intraseasonal Dynamical Evolution of the Northern Annular Mode." Diss., Georgia Institute of Technology, 2005. http://hdl.handle.net/1853/6965.
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Recent observational and modeling studies indicate a robust dynamical coupling between the stratosphere and troposphere during boreal winter. This coupling occurs in association with the Northern Annular Mode (NAM), which itself accounts for a significant fraction of the variability of the extratropical circulation. While monthly NAM dynamics have been studied previously, the mechanisms that give rise to NAM variability on short intraseasonal timescale are still unclear.
We perform regression analyses, case studies, and composites based on periods of dynamical growth/decay to investigate the roles of the different proposed mechanisms in driving the atmospheric variability observed in association with the NAM on short intraseasonal timescales. More specifically, lag-regression analyses are used to identify the mean canonical structures present during the evolution of a typical NAM event. Illustrative case studies of robust stratospheric NAM events but with different tropospheric signals are contrasted in order to identify the underlying dynamical reasons for the observed differences. Finally, composite analyses of NAM tendencies are performed to isolate the structural and dynamical evolution of NAM events. Zonal-mean and three-dimensional eddy-flux diagnoses are used to examine the role of eddy-mean flow interaction in driving the wind tendencies characteristic of the NAM. In particular, Plumb flux analyses are employed to quantify the contribution of regional stationary wave anomalies toward the zonal mean wind tendency field. Potential vorticity inversions are also used to determine the role of stratospheric anomalies in inducing tropospheric circulations.
The case study analyses indicate that preexisting tropospheric PV anomalies can mask the downward penetration of an initial stratospheric NAM signal into the troposphere. PV inversions further suggest that a minimum requirement for a direct downward stratospheric influence is that the stratospheric NAM signal be robust in the lower stratosphere.
The dynamical composites show a remarkable degree of reverse symmetry between the zonal-mean dynamical evolution of positive and negative NAM events. Anomalous Eliassen-Palm fluxes are observed in the troposphere and stratosphere, consistent with index of refraction considerations and an indirect downward influence of the stratosphere on the troposphere. The patterns of anomalous wave driving, primarily due to low-frequency planetary scale waves, provide the main forcing of the zonal mean wind tendency field. Regional wave activity fluxes indicate that the wave driving pattern represents the manifestation of planetary scale anomalies over the North Atlantic.
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Thomas, Jessica Ann. "The Tempo and Mode of Invertebrate Molecular Evolution." Thesis, University of Sussex, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.487903.
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Dorris, Mark. "Mode and tempo in the evolution of nematodes." Thesis, University of Edinburgh, 1999. http://hdl.handle.net/1842/13696.
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Extreme variation exists in hypotheses of the taxonomy, systematics and phylogeny of the phylum Nematoda. That nematodes are important and require a unified systematic approach is not in doubt; of the organisms that are not nematodes, few can avoid their influence one way or another. The vast majority of nematodes are free-living and although they have significant impact on the composition of the biota, have little measured direct impact on humans and thus remain largely unidentified. A notable exception is the model organism Caenorhabditis elegans, of which more is known than possibly any other eukaryote. Other nematodes, most notably parasites of plants and animals, have received widespread attention. In between, lie a myriad of life-history, developmental, ecological, structural, and functional relationships waiting to be resolved. This requires phylogeny. The data used to infer this phylogeny must itself be unified from all available reliable sources. In this work, current molecular tools combined with analytical observation are used to address some important junctures in nematode evolution. These are assessed in terms of temporal and spatial radiations inferred by SSUrDNA phylogeny. An objective approach to phylogeny is implemented where no a priori assumptions are made on the data. Phylogenies, and underlying evolutionary models are statistically evaluated. Morphological and ecological corroboration for observed phylogenetic patterns is sought. This combined approach is essential to help reconcile taxonomy with a systematic approach based on an effective consolidated phylogenetic perspective. Special reference is made to Strongyloidoidea and the genus Strongyloides in particular for which a strategy for extraction of quality DNA from formalin fixed Strongyloides samples is implemented.
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Monroe, Melanie. "The tempo and mode of evolution : a neontological reappraisal." Doctoral thesis, Umeå universitet, Institutionen för ekologi, miljö och geovetenskap, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-49761.
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The theory of “punctuated equilibrium” suggests that species evolve rapidly during or immediately upon speciation, “punctuating” long periods of little or no morphological evolution. Here I confirm that body size differences within clades of birds and mammals are best explained using a model of punctuated evolution. This allows me to suggest that rates of speciation and extinction are responsible for why there are more small mammals than large, as large mammals likely speciate and go extinct at a higher rate than small mammals, and hence undergo cladogenetic change more often. Likewise, mammals appear to evolve at a higher rate than birds, because mammals, as a whole, speciate and go extinct at a higher rate than birds. Furthermore I show that mass extinctions and competition, i.e. forms of natural selection, do not seem to explain differences in body size between species on a macroevolutionary scale. Taken together, these findings not only contradict the idea that apparently different rates of evolution are due to differential selection intensities, and emphasize the importance of the speciation process in evolution, but raise the intriguing question as to what limits evolution in established species. Here I suggest that phenotypic traits, dependent on one another for development and/or function may constrain evolution by exerting stabilizing selection from within the organism, as opposed to external environmental selection, which has been the main focus of evolutionary studies thus far.Teorin om "punkterad jämvikt" säger att arter utvecklas snabbt under och omedelbart efter artbildning, vilket "punkterar" långa perioder med lite eller ingen morfologisk föränding. I den här avhandlingen visar jag att skillnader i kroppsstorlek inom klader (grupp med gemensam förfader) hos fåglar och däggdjur förklaras bäst när man använder en modell med punkterad evolution. Detta gör i sin tur att jag kan föreslå att hastigheten var med artbildning och utdöende sker, förklarar varför det finns fler små däggdjur än stora, eftersom stora däggdjur sannolikt bildar nya arter och dör ut med en högre hastighet än små däggdjur. Likaså förefaller däggdjur i sin helhet att evolvera med en högre hastighet än fåglar, detta eftersom däggdjur bildar nya arter och dör ut med en högre hastighet än fåglar. Dessutom visar jag att massutdöenden och konkurrens (naturlig selektion) inte verkar förklara skillnader mellan arter över makroevolutionära skalor (över geologisk tid). Sammantaget motsäger dessa resultat inte bara idén om att skenbart olika hastighet på evolution främst beror på skillnader i selektionstryck utan understryker också vikten av artbildningsprocessen som en viktig faktor som styr evolutionens hastighet. Dessutom leder dessa resultat till frågan om vad som begränsar evolutionen hos redan etablerade arter. Här föreslår jag att fenotypiska karaktärsdrag som är beroende av varandra för sin funktion och utveckling kan begränsa evolutionen genom att utöva stabiliserande selektion inifrån organismen, i motsats till selektion från den omgivande miljön vilket har varit fokus för de flesta evolutionära studier hittills.
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Grott, Matthias. "On the evolution and simulation of strange mode instabilities." Doctoral thesis, [S.l.] : [s.n.], 2003. http://webdoc.sub.gwdg.de/diss/2003/grott/grott.pdf.
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LAMBOLEZ, ANNE-MARIE. "Evolution des formes galeniques et mode d'administration de l'insuline." Strasbourg 1, 1989. http://www.theses.fr/1989STR15029.
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Jousselin, Emmanuelle. "Evolution du mode de pollinisation dans le mutualisme ficus/agaonide." Montpellier, ENSA, 2001. http://www.theses.fr/2001ENSA0003.
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González, Mula Almudena. "Mode de vie d'Agrobacterium tumefaciens dans la tumeur." Thesis, Université Paris-Saclay (ComUE), 2017. http://www.theses.fr/2017SACLS130.
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Le phytopathogène Agrobacterium tumefaciens est l'agent causal de la maladie appelée galle du collet, et est capable d'infecter plus de 90 familles de plantes dicotylédones. Cette ∝-protéobactérie appartient à la famille Rhizobiaceae. A. tumefaciens est un complexe de différentes espèces regroupées en 10 génomovars (G1 à G8 et G13). A. tumefaciens C58 appartient au groupe du G8. Son génome est constitué de 4 réplicons : 1 chromosome circulaire, 1 chromosome linéaire et des 2 plasmides dispensables : pAt (pour A.tumefaciens) et pTi (pour Tumor inducing, qui est requis pour la virulence). Pour explorer de nouveaux aspects du mode de vie d’A. tumefaciens, et en particulier l'interaction entre la bactérie et sa plante hôte, deux approches différentes ont été utilisées pour identifier, caractériser et analyser les gènes qui pourraient jouer un rôle dans l'adaptation des bactéries à la tumeur. Une expérience de l'évolution par des passages en série de trois souches différentes de l'agent pathogène sur la plante hôte Solanum lycopersicum a été effectuée afin de clarifier la dynamique évolutive du génome au cours de l'infection. Parallèlement, une étude de différents transcriptomes (in planta et in vitro) a été réalisée et étudiée pour élucider des gènes bactériens candidats impliqués dans l'interaction de la bactérie avec la plante et divers composés produits dans la tumeur. Ce travail tente de donner une vue plus générale du processus d'adaptation de la bactérie à la niche écologique qui est la tumeurAgrobacterium tumefaciens is the causal agent of the plant disease called crowngall, and it’s able to infect more than 90 families of dicotyledonous plants. It is an α-Proteobacterium and belongs to the Rhizobiaceae family. A. tumefaciens is a complex of different species grouped in 10 genomovars (G1 to G8, and G13). A. tumefaciens C58 belongs to the G8 group. Its genome consists in 4 replicons: 1 chromosome circular, 1 chromosome linear and 2 dispensable plasmids: pAt (for A. tumefaciens) and pTi (for Tumor inducing), which is required for virulence. To explore new aspects of the A. tumefaciens lifestyle, and in particular the interaction between the bacteria and its plant host, two different approaches have been used to identify, characterize and analyze genes that could play a role in the adaptation of the bacteria to tumor lifestyle. An evolution experiment by serial passages of three different strains of thepathogen on the host plant Solanum lycopersicum has been carried out to clarify the evolutionary dynamics of the genome during the course of infection. In parallel, a study of different transcriptomes (in planta and in vitro) was performed and studied to elucidate bacterial candidate genes involved in the interaction of the bacteria with the plant and various compounds produced in the tumor. This work attempts to give a more general view of the process of adaptation of the bacteria to the ecological niche that is the tumor
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Grosmaire, Manon. "Caractérisation du mode de reproduction pseudogame chez l’espèce de nématode Mesorhabditis belari." Thesis, Lyon, 2018. http://www.theses.fr/2018LYSE1151/document.
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Chez les espèces pseudogames, les femelles utilisent les spermatozoïdes des mâles d'autres espèces pour activer leurs ovocytes et produire de nouvelles femelles sans utiliser l'ADN paternel. Ici, nous montrons un nouveau mode de reproduction pseudogame découvert chez l'espèce de nématode Mesorhabditis belari chez qui 8% de mâles conspécifiques sont présents. Ces mâles sont nécessaires pour féconder les ovocytes mais leurs gènes ne seront transmis qu'à leur fils et non à leurs filles. En effet, les femelles produisent deux types d’ovocytes, un type amphimixique où les ADN paternel et maternel constitueront le génome du zygote qui deviendra un mâle et un type gynogénétique ou l’ADN paternel déclenchera le développement du zygote mais où seul l’ADN maternel constituera le génome du zygote qui deviendra une femelle. Ainsi, la production de mâles n'a pas d'incidence sur la diversité génétique des femelles. Par une approche de théorie des jeux, nous avons montré que la production des mâles dans une faible proportion constitue une stratégie évolutivement stable seulement si les fils sont plus enclins à se reproduire avec leurs sœurs. Nous avons validé cette prédiction par une approche expérimentale en montrant une préférence entre les frères et les soeurs pour la reproduction.En parallèle, nous nous sommes intéressés aux bases moléculaires et cellulaires soutenant un tel mode de reproduction. Dans les embryons amphimixiques, la méiose femelle produit un pronoyau haploïde et la diploïdie est restaurée grâce au pronoyau paternel également haploïde. Dans les embryons gynogénétiques, l’ADN paternel ne se décondense pas, la méiose femelle est incomplète et produit un pronoyau diploïde afin de maintenir la diploïdie du zygote. Nous avons donc étudié le développement précoce des embryons de M. belari, et essayé de comprendre le type de déterminisme du sexe présent chez cette espèceIn pseudogamous species, females use the sperm of males from another species to activate their oocytes and produce females, without using the sperm DNA. Here we report a novel reproductive strategy found in the pseudogamous nematodeMesorhabditis belari, which produces its own males at low frequency. We find that the 8% of M. belari males are necessary to fertilize all oocytes but pass on their genes only to males, and never to females. Thus, the production of males has no impact on the genetic diversity of females. Using game theory, we show that the production of males at low frequency constitutes an efficient strategy only if sons are more likely to mate with their sisters. We validate this prediction experimentally by revealing a mating preference between siblings. We uncover the remarkable reproductive strategy of parthenogenetic females that pay the cost of producing males while males do not spread their genes.In parallel, we tried to understand the cellular and molecular basis at the origin of such a reproductive mode. In amphimixis embryos, female meiosis produces an haploid pronucleus and ploidy is restored with the male haploid pronucleus. In gynogenetic embryos, paternel DNA don't decondense, female meiosis is incomplete leading to a diploid pronucleus in order to maintain the diploidy of the organism. We then studied the early development of the embryos of M. belari and the type of sex determinism in this species
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Simons, Erin L. R. "The Evolution of Forelimb Morphology and Flight Mode in Extant Birds." Ohio University / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1250094326.
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Jones, Caleb. "Evolutionary changes in development associated with a transition in larval nutritional mode in spiralians." Thesis, California State University, Long Beach, 2015. http://pqdtopen.proquest.com/#viewpdf?dispub=1596978.
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The larval nutritional mode of marine invertebrates is an important life history trait that has strong effects on their ecology and evolution. Increases in egg size and transitions from feeding to nonfeeding larvae have happened repeatedly. In Spiralia, a change in cytoplasm allocated to macromeres at the 8-cell stage (that could delay the development of a functional gut) may accompany these transitions. The first part of this thesis describes the development of the gastropod Crepidula williamsi and compares it to the closely related C. fornicata, with a focus on changes in allocation to macromeres and the development of a functional gut. The second part is a phylogenetic comparison of egg size and allocation to macromeres in 44 species of spiralians, which revealed a significant correlation between the two. A phylogenetic comparison like this one has not previously been done on the development of such diverse marine invertebrate taxa.
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Newsam, C. "Calcareous nannoplankton evolution and the Paleogene greenhouse to icehouse climate-mode transition." Thesis, University College London (University of London), 2017. http://discovery.ucl.ac.uk/1541282/.
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This thesis addresses calcareous nannoplankton evolutionary and palaeoecological response across the Paleogene greenhouse to icehouse transition using newly drilled material from Sites U1408 and U1411 (IODP Expedition 342) in the North Atlantic. Calcareous nannoplankton were the dominant oceanic phytoplankton group in the early Paleogene yet declined in diversity and underwent significant assemblage restructuring through the middle Eocene to early Oligocene, coinciding with major climatic reorganisation. However the structure and timing of this nannoplankton response is poorly constrained due to few records of appropriate stratigraphic resolution. Here, exceptionally preserved calcareous nannofossils from stratigraphically expanded packages of Paleogene clay-rich drift sediments from IODP Expedition 342 are used to document diversity loss and population shifts in order to interpret the relationship between plankton evolution and palaeoclimatic and palaeoceanographic change in the North Atlantic across this key interval, with focus on abrupt climatic change at the Middle Eocene Climatic Optimum (MECO) and the Eocene-Oligocene transition (EOT). Results indicate low speciation rates combined with relatively high extinction rates drove calcareous nannoplankton diversity loss through this interval and palaeoecological analysis highlights three key intervals; middle Eocene stability, incorporating muted assemblage response to transient warming at the MECO, the late Eocene transitional phase and the EOT and early Oligocene population restructuring, with major assemblage shifts controlled by intensified surface water cooling and increased nutrient availability. Palaeoclimatic and palaeoceanographic changes through this transition led to reduced optimal habitat space for this phytoplankton group resulting in decline and extinction in many taxa and the proliferation of select opportunists at the onset of the icehouse world.
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Folgar, Carlos Eduardo. "Structure Evolution of Silica Aerogel under a Microwave Field." Diss., Virginia Tech, 2010. http://hdl.handle.net/10919/27801.
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Structure evolution of silica aerogel was studied in microwave- and conventionally processed samples over the temperature range from 25 to 1200â °C. The samples were produced using sol-gel processing and dried under carbon dioxide supercritical conditions. After drying, the monolithic samples received a thermal treatment at different programmed temperatures in two different ovens, conventional and microwave. The microwave process was performed using a single mode microwave oven at 2.45GHz. Dielectric properties were measured using the cavity perturbation method, and structural characterization was carried out using a variety of techniques, including absorption surface analysis, Helium pycnometry, Archimedes principle, Fourier transform infrared spectroscopy, X-ray diffraction, and high resolution microscopy. The data obtained revealed that structural differences do exist between microwave- and conventionally processed samples.
Three different regions were identified from the structural characterization of the samples. Regions I exhibited a structure densification at temperatures between 25 and 850â °C. Region II was characterized by a bulk densification in the temperature range from 850 to 1200â °C. Region III was represented by the onset of crystallization above 1200â °C. Explanation and possible causes behind the structural differences observed in each region are provided. In general, the structure evolution observed in microwave- and conventionally processed samples followed the same order, but occurred at lower temperature for the microwave process.Ph. D.
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Russell, Shelbi Lianne. "Mode and Fidelity of Bacterial Symbiont Transmission and Its Impact on Symbiont Genome Evolution." Thesis, Harvard University, 2016. http://nrs.harvard.edu/urn-3:HUL.InstRepos:33493576.
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Mutualistic symbioses have enabled the colonization of novel habitats and niches in a large array of eukaryotic and bacterial taxa. Reliable mechanisms of symbiont transmission between host generations are necessary to stabilize these associations over evolutionary time. Historically, symbionts have been categorized as either vertically transmitted from the parents to offspring or horizontally transmitted through the environment. The route between hosts influences how symbiont populations are connected between hosts and between geographic localities. Over evolutionary time vertical transmission leads to gene loss and genome erosion. Growing evidence from diverse associations suggests that modes utilizing both horizontal and vertical strategies exist, raising the question of how these “mixed modes” influence symbiont genome evolution. The overarching goal of my dissertation was to determine whether the mode of symbiont transmission in an obligate mutualism is consistent over evolutionary time and what impact transmission mode fidelity has on symbiont genome evolution. To test these questions, I used the chemosynthetic symbiosis between the marine bivalve Solemya velum and its gammaproteobacterial symbionts, which has been reported to transmit its symbionts vertically through the ovary, but bears none of the genomic hallmarks of strict vertical transmission.
In this work, I used population genomics of S. velum subpopulations sampled from five localities along the New England coast, from Massachusetts to North Carolina, to test for evidence of horizontal transmission in the evolutionary history of this species. These analyses revealed that symbionts and mitochondria do not exhibit concordant genealogies, divergent symbiont lineages have come into contact and recombined, and symbiont genomes have experienced large-scale structural changes mediated by mobile elements and horizontal gene transfer. In total, these lines of evidence indicate that a substantial amount of horizontal transmission has occurred in the recent history of this association. The vertical transmission route through host tissues was characterized via in situ hybridization to symbiont 16S rRNA in adult host tissues and by qPCR of the rhlE gene in spawned eggs. These data showed that symbionts are present at low abundance in the ovary, associated with the supportive cells and mature oocytes, and each spawned egg contains approximately 50-100 copies of the symbiont genome. Lastly, I tested for evidence of mixed transmission modes in symbiont populations contained within host tissues (each host gill contains more than a billion symbiont cells), by deep-coverage whole genome sequencing. Using a novel variant-calling procedure, I detected low amounts of genetic variation among symbiont genomes within a host relative to between hosts. However, the variant sites that were present were correlated in position along the genome, present on the same chromosome, and segregating in the symbiont population at large, suggesting that these variants arose via recombination with a variant symbiont genotype introduced by horizontal transmission.
In total, this work supports the existence of mixed transmission modes in symbiotic associations and indicates they have distinct consequences for symbiont evolution. Mixed modes may provide a best-of-both-worlds strategy to ensure that hosts acquire symbionts every generation while maintaining opportunities for recombination and acquisition of novel genetic elements. These results are relevant to understanding the impact of symbiont transmission mode on genome evolution in associations ranging from mutualisms to pathogenic infections.Biology, Organismic and Evolutionary
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Heslot, Sylvie. "Evolution du mode de vie dans une communauté rurale du Cambridgeshire Little Downham, 1813-1881 /." Lille 3 : ANRT, 1988. http://catalogue.bnf.fr/ark:/12148/cb37605902r.
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Liu, Paul Z. "The evolution of a developmental mode segmentation in the intermediate germband insect, Oncopeltus fasciatus (Hemiptera) /." [Bloomington, Ind.] : Indiana University, 2005. http://wwwlib.umi.com/dissertations/fullcit/3162289.
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Thesis (Ph.D.)--Indiana University, Dept. of Biology, 2005.Title from PDF t.p. (viewed Dec. 2, 2008). Source: Dissertation Abstracts International, Volume: 66-01, Section: B, page: 0152. Chair: Peter Kloosterman.
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Potel, Agathe. "Evolution du lien cadre-entreprise à travers les trentas : nature de l'échange et mode d'engagement." Thesis, Paris 2, 2011. http://www.theses.fr/2011PA020002.
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Actuellement les comportements décrits chez les nouvelles générations inquiètent les entreprises. Ces incompréhensions vont au-delà de difficultés de communication entre les générations : la révolution des NTIC, l’évolution du rapport au travail, à l’autorité, aux réseaux sociaux, à l’international sont autant de caractéristiques présentées comme spécifiques de la génération Y.Ce travail étudie l’engagement envers l’entreprise des cadres trentas considérés comme les aînés de la génération Y et les termes du contrat psychologique valorisés par cette population. A été mobilisé le double cadre théorique de l’échange social et du contrat psychologique d’une part, et de l’engagement organisationnel d’autre part.La démarche de recherche est qualitative de nature exploratoire. Une technique projective détournée, la« lettre à un ami » a été proposée pour cerner les dimensions émergentes, partagées et valorisées du rapport à l’entreprise. Cette lettre a été rédigée par 547 cadres français et étrangers de 30/32 ans de tous les métiers et secteurs d’une TGE française, dans le cadre privilégié d’une formation.Les résultats qualitatifs sont de trois ordres :− les cadres trentas manifestent une grande homogénéité de réponses indépendamment de leurs caractéristiques individuelles. Leurs principales préoccupations concernent le travail, la carrière et le réseau. L’analyse fine de leurs représentations permet de les considérer comme représentatifs des aînés des Y ;− leur engagement vis-à-vis de l’entreprise est lié à la perception d’un échange satisfaisant et réciproque. Les termes de l’échange concernent ce qu’offre l’entreprise et ce qu’elle attend d’eux ;− l’identification des termes de l’échange permet de préciser comment l’entreprise et le management peuvent évoluer pour rencontrer leurs attentes et favoriser leur engagement vis-à-vis de l’entreprise.En conclusion, des recommandations aux entreprises sont proposées en matière de gestion des générations montantesAt present, companies are worried about the demonstrated behaviors of the new generation. Their lack ofunderstanding goes beyond problems of communication between the generations: it now includes the ITrevolution, the evolution of individuals’ relationships with their work, authority issues, social networks andglobalization are characteristics presented as specific to generation Y.The purpose of this work is to study the commitment of thirty-year-old executives, considered as the elders ofgeneration Y, towards their companies, and to enlighten the terms of the psychological contract developed bythis population. The double theoretical frame of the social exchange and the psychological contract has beenutilized on one hand, and the organizational commitment on the other hand.This research is a qualitative one with an exploratory nature. A diverted projective technique, the "letter to afriend", has been used to define the emergent, shared and enhanced dimensions of the relationship with thecompany. This letter has been written by 547 French and foreign executives approximately around 30-32years old, from any kind of job or area of a large French company, within the dedicated frame of training.The qualitative results are of the following three natures:− The thirty-year-old executives show a distinct homogeneity in their answers independent of their personalcharacteristics. Their main concerns are about work, career and network. Through, he detailed analysis oftheir composition, they can be considered as representative of the elders of generation Y;− Their commitment towards the company is bound to the perception of a satisfying and mutual exchange. Theterms of the exchange concern what the company offers and expects from them;− The identification of the terms of the exchange helps to specify how the company and the management canevolve to meet their expectations and encourage their commitment towards the company.As a conclusion, recommendations are made to HR and managers concerning the new generation
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Erdahl, Mike. "Planned Evolution of Range Telemetry and Communications into the Public Data Network." International Foundation for Telemetering, 1994. http://hdl.handle.net/10150/611743.
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International Telemetering Conference Proceedings / October 17-20, 1994 / Town & Country Hotel and Conference Center, San Diego, CaliforniaThe area of range telemetry and communications has been under budget constraints and interoperability enhancement requirements for some time. The near-term onslaught of multimedia communications offerings by telephony and communications companies is certain to cause range engineering personnel to conduct extensive research and possibly make numerous decisions on procurements and technologies before standards are finalized. This paper will address a low-risk migration path for range telemetry to the new multimedia communications for ranges based on current capabilities. This migration path has an end goal of positioning the ranges to take advantage of future multimedia communications as they become available, while leveraging off of current products and procurements, without a major investment.
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Kushnir, Alexandra Roma Larisa. "Permeability development and evolution in volcanic systems : insights from nature and laboratory experiments." Thesis, Orléans, 2016. http://www.theses.fr/2016ORLE2006/document.
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La transition entre le comportement effusif et explosif des volcans de magma riche en silice est en partie contrôlée par la capacité des surpressions gazeuses à se dissiper hors du magma. La libération efficace des gaz est associée aux éruptions effusives tandis que la rétention de ces gaz contribue aux processus explosifs. L’une des approches pour évaluer la facilité d’échappement des gaz est de considérer l’évolution et le développement de la perméabilité dans la colonne magmatique et dans l'édifice. J'évalue dans ce travail de thèse le rôle des changements post-mise en place sur la microstructure dans des andésites basaltiques du Merapi (Indonésie). La perméabilité de ces roches est principalement contrôlée par des fissures liées à leur mise en place. Malgré l’influence importante de ces fissures post-mise en place pour dégazer à travers l'édifice, elles ne contribuent pas au dégazage intrinsique du magma en cours d’ascension. Pour s’affranchir de l'influence des microstructures post-mise en place du magma, j'étudie le développement et l'évolution in situ des réseaux perméables en déformant des magmas à deux phases (bulles de gaz et liquide silicaté) en cisaillement simple dans une presse Paterson selon des viscosités et des vitesses de déformation réalistes pour la partie haute des conduits des strato-volcans. Le développement de la perméabilité est confirmé in situ et se développe à des vitesses de déformation supérieures à 4,5 x 10⁻⁴ s⁻¹. À des vitesses de déformation élevées (> 5 x 10⁻⁴ s⁻¹) le magma est fragile et l’échappement du gaz est lente, facilitée par l'interconnexion de courtes fractures de Mode I. À des vitesses de déformation < 5 × 10⁻⁴ s⁻¹, le magma se comporte à la fois de manière fragile et visqueuse et la perméabilité se développe lorsque la déformation est importante; le gaz s’échappe rapidement par de longues fractures de Mode I bien développées. Les fractures de Mode I sont idéalement orientées pour le dégazage du conduit central et sont, surtout, soumises à peu de déformation jusqu'à ce qu'elles soient réorientées dans la direction de cisaillement. Ces caractéristiques de dégazage peuvent, à long terme, favoriser un dynamisme éruptif effussifThe transition from effusive to explosive behaviour at silicic volcanoes is, in part, governed by how efficiently gas overpressures are dissipated from the volcanic plumbing. Efficient gas release is associated with effusive eruptions while inadequate outgassing contributes to explosive processes. One approach to assessing the facility of gas escape is by considering how permeability develops and evolves in the magma column and surrounding edifice. Here, I appraise the role of post-emplacement changes to microstructure in edifice-forming basaltic andesites from Merapi (Indonesia). The permeability of these rocks is dominantly crack-controlled and while these features exert important controls on gas escape through the edifice, they do not represent the escape pathways available to gas within ascending magma. To avoid the influence of postemplacement microstructure, I investigate the development and evolution of permeable networks in magmas by deforming initially impermeable two-phase magmas in simple shear. This is done in a Paterson apparatus at viscosities and shear strain rates appropriate to upper conduits in stratovolcanoes. Permeability development is confirmed in situ and develops at moderate to high shear strain rates (> 4.5 × 10⁻⁴ s⁻¹). At very high strain rates (> 5 × 10⁻⁴ s⁻¹) the magma behaves in a brittle manner and gas egress is slow, facilitated by the interconnection of short, Mode I fractures. At moderate shear strain rates (< 5 × 10⁻⁴ s⁻¹), the magma displays both brittle and viscous behaviour and permeability develops at high strain; gas escape is rapid owing to long, well-developed, sample-length Mode I fractures. Mode I fractures are ideally oriented for outgassing of the central conduit and, critically, accommodate little deformation until they are rotated into the direction of shear, making them long-lived outgassing features that may favour volcanic effusion
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Majda, Stephan [Verfasser], and Jens [Akademischer Betreuer] Boenigk. "Evolution in Chrysophyceae regarding the nutritional mode and intraspecific variation based on comparative genomics / Stephan Majda ; Betreuer: Jens Boenigk." Duisburg, 2020. http://d-nb.info/1233199943/34.
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Devaux, Ophélie. "Analysis and optimization of mixed-mode conical adhesively bonded joints under thermo-mechanical loadings." Thesis, Brest, 2015. http://www.theses.fr/2015BRES0048/document.
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Dans I'industrie spatiale, I'optimisation des structures composites du point de vue cycles de fabrication, gain de masse et amélioration des performances passe aujourd'hui par I'introduction de jonctions collées en remplacement/complément de liaisons boulonnées ou rivetées. Les lanceurs sont des structures complexes qui nécessitent de prendre en compte les contraintes liées à la fabrication de structures de grandes tailles, I'influence des conditions de transport et de stockage, ainsi que les différents spectres de chargements thermo-mécaniques rencontrés au cours de la phase de lancement. Le but de ce travail a été de développer un outil prédictif du comportement mécanique de I'adhésif Hysol EA-9321, matériau utilisé dans cette étude, à tout instant du cycle de vie de la structure sur lequel il est utilisé, la structure SYLDA. La caractérisation et la modélisation d'un couplage thermo-cinétique d'un tel adhésif ont tout d'abord été réalisées en vue de déterminer la distribution du taux de polymérisation et de la température dans un assemblage collé quel que soit le chargement thermique appliqué. Le comportement mécanique de l'adhésif a ensuite été étudié expérimentalement via I'essai Arcan Evolution, ce qui a constitué une base de données expérimentales à divers taux de polymérisation adaptée à I'identification du modèle de comportement. Plusieurs modèles élasto-plastique et élasto-visco-plastique basés sur celui de Mahnken-Schlimmer ont été implantés dans un code de calcul éléments finis afin de prédire le comportement 3D de l'adhésif Hysol EA-9321. Une procédure globale d'identification, basée sur un couplage entre calculs éléments finis et une procédure d'optimisation, a permis d'identifier les différents paramètres des lois de comportement. Une extension de ces modèles à la visco-élasticité a été numériquement proposée. Enfin, une comparaison numérique entre une liaison conique et une liaison semblable à celle trouvée sur la structure spatiale étudiée a permis de proposer un essai représentatif du comportement de I'adhésif sur un tel assemblage. Cet essai servira, dans une étude complémentaire, à valider les modèles de comportement développésIn the aerospace industry, composite structures are nowadays optimized with adhesively bonded joints supplemented by/or completed with mechanical fasteners such as bolts, rivets or welds. The structural design of launch vehicles is complex and must take into account lot of constraints related to large-scale structures, influence by environment conditions during storage, transport stages and thermo-mechanical stresses applied during launcher's flight. The purpose of this work was to provide a numerical tool for predicting the mechanical behaviour of the Adhesive Hysol EA-9321 in a spatial bonded assembly such as the SYLDA structure during its life course. First of all, a thermo-kinetic coupling was experimentally and numerically investigated to describe the couple (curing degree-temperature) in a bonded assembly regardless of the thermal load applied. Then, an experimental database was made by studying the mechanical behaviour of the adhesive under proportional loadings, using the Arcan Evolution experimental device. Cure-dependent elastoplastic and elasto-visco-plastic model based on Mahnken-Schlimmer constitutive laws were proposed in order to describe the 3D mechanical behaviour of the adhesive Hysol EA-9321. A global identification strategy allowed identifying material parameters by coupling finite element computations and optimization procedure. An extension of those models to the visco-elasticity was evenly provided. At last, a conical bonded joint and a bonded assembly in the SYLDA structure were numerically compared to propose a test representative of the adhesive behaviour in the SYLDA. The latter will aim at validating the constitutive laws established
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DESCHAMPS, HENRI DOMINIQUE. "Hypersensibilite sino-carotidienne : evolution a moyen et a long terme des patients traites par stimulation cardiaque monochambre ventriculaire (mode v.v.i.)." Clermont-Ferrand 1, 1988. http://www.theses.fr/1988CLF11027.
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Feichtner, Thorsten [Verfasser], Bert [Gutachter] Hecht, and Tobias [Gutachter] Brixner. "Optimal Design of Focusing Nanoantennas for Light : Novel Approaches: From Evolution to Mode-Matching / Thorsten Feichtner ; Gutachter: Bert Hecht, Tobias Brixner." Würzburg : Universität Würzburg, 2016. http://d-nb.info/1147681929/34.
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Parsy, François. "Contribution à l'intégration d'un isolateur optique sur verre : fonctions réciproques et non réciproques de contrôle de la polarisation." Thesis, Grenoble, 2013. http://www.theses.fr/2013GRENT106/document.
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L'essor des télécommunications sur fibres a conduit depuis quarante ans au développement des composants optiques intégrés. Cependant, en raison de difficultés technologiques, un dispositif n'a pas encore été réalisé de façon satisfaisante : il s'agit de l'isolateur optique, dont la fonction est de propager la lumière dans un seul sens. Ces travaux s'inscrivent dans cette problématique puisqu'ils visent à l'intégration d'un isolateur grâce à la technologie de l'échange d'ions Na+/Ag+ sur verre. La configuration adoptée se compose de trois éléments sur puce : un séparateur de polarisation et deux rotateurs de polarisation à 45 °, l'un réciproque et l'autre non. Le séparateur de polarisation a été réalisé sous la forme d'une jonction Y asymétrique. Après une étude théorique, nous présentons le procédé de fabrication ainsi que les résultats expérimentaux obtenus. Les diaphonies mesurées sont à l'état de l'art, elles dépassent (31,1 ± 0,4) dB et (32,7 ± 0,4) dB en mode TE et TM sur une plage spectrale supérieure à 70 nm. Nous avons mené l'étude du rotateur Faraday en collaboration avec le Laboratoire Télécom Claude Chappe de Saint Etienne pour la partie magnéto-optique. La structure employée est un guide d'onde à enterrage différentiel sur lequel est déposé un matériau magnéto-optique par un procédé sol-gel. Un angle de rotation non-réciproque de 50 ° a été mesuré, validant ainsi l'approche hybride. Un nouveau procédé de fabrication est également présenté pour un rotateur réciproque à évolution de mode adiabatique. Celui-ci consiste en un enterrage sous champ présentant une inhomogénéité transverse. Nous proposons finalement une méthode de fabrication de l'isolateur complet basée sur l'intégration monolithique des différents élémentsFor the past forty years, the growth of fiber telecommunications has led to the development of integrated optical components. However, due to technological issues, a device has not yet been realized: the optical isolator, which propagates light in a single direction. Our work fits into this context. It deals with the integration of an isolator using the Na+/Ag+ ion-exchange technology. The configuration we adopted consists of three elements on chip: a polarization splitter and two 45 ° polarization rotators, one is reciprocal and the other is not. The polarization splitter has been realized in the shape of an asymmetrical Y junction. After a theoretical study, we present the fabrication process and experimental results. State-of-the-art diaphonies of (31.1 ± 0.4) dB and (32.7 ± 0.4) dB have been measured in TE and TM mode over a bandwidth larger than 70 nm. The magneto-optical part of the study has been undertaken in collaboration with the Laboratoire Télécom Claude Chappe (LT2C) from Saint Etienne, France. The Faraday rotator is a selectively buried waveguide on which a magneto-optical material has been deposited using a sol-gel process. A non-reciprocal rotation of 50 ° has been measured, hence validating the hybrid approach. A novel fabrication process is presented for a reciprocal mode-evolution polarization rotator. The process consists in the burring of a waveguide under an electric field presenting a transverse inhomogeneity. We finally propose a fabrication method of the complete optical isolator. It is based on the monolithic integration of the three elements
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Volland-Tuduri, Nathalie. "Nature et mode d'assemblage des constituants minéraux et organiques dans des Ferralsols de la région des Cerrados (Brésil). Evolution après mise en culture." Phd thesis, Université d'Orléans, 2005. http://tel.archives-ouvertes.fr/tel-00009347.
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Les Ferralsols se caractérisent par une microstructure très développée dont dépend étroitement leur fertilité. Cette microstructure repose sur des microagrégats très stables, de 50 à 800 µm de diamètre. Sous végétation naturelle comme sous pâturage, la densité apparente des sols, la taille et le mode d'assemblage des microagrégats, ainsi que la caractérisation de la matière organique, ont permis de mettre en évidence d'importantes variations avec la profondeur. Nous avons établi une typologie du mode d'assemblage des microagrégats ainsi qu'un modèle mettant en relation structure et porosité. La matière organique se singularise, en pyrolyse, par une composante de haute température, d'origine conjecturale, mais très probablement due à un effet de matrice minérale. L'ensemble des variations observées ne peuvent a priori s'expliquer par des différences d'usage du sol, mais plutôt grâce à l'activité des insectes sociaux qui sont vraisemblablement à l'origine des microagrégats.
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PALLIER, MARDON LAURENCE. "Sida : evolution du mode de transmission chez les femmes ; etude entre 1988 et 1991 pour les bouches-du-rhone et la ville de paris." Aix-Marseille 2, 1992. http://www.theses.fr/1992AIX20106.
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Datzmann, Thomas [Verfasser], and Frieder [Akademischer Betreuer] Mayer. "Reconstruction of the mode and tempo of the evolution of bats with diverse molecular markers: Morphological convergences in adaptive radiations / Thomas Datzmann. Betreuer: Frieder Mayer." Erlangen : Universitätsbibliothek der Universität Erlangen-Nürnberg, 2012. http://d-nb.info/1022931512/34.
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Vázquez, Molinero Ramón. "Comparative anatomy of Henkelotherium guimarotae (Holotheria), a late Jurassic small mammal, and its relevance for the evolution of the mode of locomotion of modern mammals." [S.l.] : [s.n.], 2004. http://www.diss.fu-berlin.de/2004/12/index.html.
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Roger, Frédéric. "Mode d’évolution et taxonomie au sein du genre Aeromonas : que nous apprend l'étude de la diversité génétique et génomique ?" Thesis, Montpellier 1, 2012. http://www.theses.fr/2012MON13504/document.
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L'étude des bactéries pathogènes opportunistes d'origine environnementale ayant des modes de vie variés, libre et autonome ou contraint à une niche spécifique représentée par l'hôte, présente un intérêt dans la compréhension de l'adaptation des bactéries à leurs hôtes et de l'apparition de nouveaux pathogènes. Le genre Aeromonas regroupe des bactéries communes des milieux aquatiques, principalement des eaux douces. Elles sont capables d'entretenir différents types de relations avec leurs hôtes (parasitisme/symbiose) et peuvent être hébergées par un large spectre d'organismes. Chez l'homme, elles sont la cause d'une large variété d'infections (gastroentérite, bactériémie, infection de la peau et des tissus mous, etc.) mais les difficultés d'identification des souches et une taxonomie confuse engendrent une méconnaissance de la pathogénicité réelle des différentes espèces décrites.Le but de ce travail était d'étudier les mécanismes d'évolution génomique et génétique à l'origine de la remarquable capacité d'adaptation des Aeromonas à leurs hôtes, notamment à l'homme. Une analyse comparative de la diversité génétique et génomique d'une large collection de 195 souches représentative des différentes espèces du genre et d'origines variées (humaine, animale et environnementale) a été menée. La diversité génétique a été appréhendée au moyen d'une approche multilocus incluant l'étude des séquences de 7 gènes de ménage (dnaK, gltA, gyrB, radA, rpoB, tsf, zipA). En parallèle, nous avons étudié la variabilité des copies multiples du gène rrs en explorant leur diversité génétique par une méthode d'électrophorèse en condition dénaturante (PCR-TTGE) et la variabilité du nombre et de la répartition des opérons rrn dans le chromosome de ces bactéries par électrophorèse en champ pulsé.Ces différentes approches nous ont permis de mettre en évidence : i) une diversité très élevée des 7 gènes de ménage analysés ainsi que l'existence de transferts latéraux, ii) l'existence de sous-groupes de souches adaptées à un hôte ou à une localisation anatomique particulière, iii) un nombre important d'opérons rrn (8 à 11), iv) l'existence de profils de distribution chromosomique des opérons rrn spécifique d'espèce ou de groupes d'espèces proches, v) une forte proportion (41,5%) des souches présentant une hétérogénéité de séquences des différentes copies du gène rrs. Nos résultats montrent également la valeur taxonomique de l'étude de la diversité génétique et génomique à l'aide des approches proposées au sein du genre Aeromonas.Nous montrons que : i) l'ARN ribosomique 16S est un marqueur informatif pour étudier les modes d'évolution et conduire des études de taxonomie mixte et consensuelle dans le genre Aeromonas à condition d'étudier la diversité de ses multiples copies, ii) A. caviae présente des caractéristiques génétiques particulières témoignant d'un processus d'adaptation en cours à une niche écologique que nous supposons être l'intestin humain. Nos résultats supportent également un mode d'évolution des bactéries du genre Aeromonas dit en complexes d'espèces accompagné de phénomènes de spéciation pouvant en partie expliquer les difficultés rencontrées pour établir une taxonomie claire du genre AeromonasAbstract :Studying opportunistic pathogenic bacteria with an environmental origin and a wide variety of lifestyles, either free-living or host-adapted, is useful to improve the understanding of bacterial adaptation to hosts and the emergence of novel pathogens. The genus Aeromonas groups water-living bacteria, mainly in freshwater. They are able to support several types of relations with their hosts (parasitism/ symbiosis) and are harbored by a large spectrum of hosts. In human, they are involved in a wide range of infections (gastroenteritis, bacteraemia, wound and soft tissue infection, etc.) but difficulties in identifying strains and a confused taxonomy results in incomplete knowledge of the real strain pathogenicity of each described species.The aim of this work was to study the mechanisms of genomic and genetic evolution related to the outstanding ability of Aeromonas adaptation to host, including human. We led a comparative analysis of the genetic and genomic diversity on a large strain collection (195 strains) representative of the species of the genus and from various sources (human, animal, environmental). We studied the genetic diversity using a 7 housekeeping gene multilocus strain analysis (dnaK, gltA, gyrB, radA, rpoB, tsf, zipA). We also described the variability in the i) rrs multiple gene copies using a PRC-TTGE method and ii) the number and distribution of the rrn operons within the chromosome using a pulse field gel electrophoresis. Our results also showed the taxonomic value of the study of genetic and genomic diversity using the approaches proposed in the genus Aeromonas.These various approaches enabled us to highlight: i) a high genetic diversity in the housekeeping genes together with horizontal gene transfers events, ii) some clusters that were either host-adapted or adapted to particular anatomical locations, iii) a high number of rrn operons (from 8 to 11), iv) the presence of patterns of rrn operon that were either species-specific or specific to groups of closely related species, v) a high frequency (41,5%) of strains harboring sequence heterogeneities between rrs copies. We showed that: i) 16 rRNA is a valuable marker for studying the modes of evolution of aeromonads and the taxonomy within the genus Aeromonas provided that multiple copy diversity is taken into account, ii) A. caviae displays particular genetic characteristic that suggested an ongoing process of adaptation to a niche that we supposed to be human digestive tract. Our results also support an evolution mode in complex of species with some speciation process that could at least in part explain difficulties for determining a clarified taxonomy within the genus Aeromonas
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Grimm, Guido W. "Tracing the mode and speed of intrageneric evolution a phylogenetic case study on genus Acer L. (Aceraceae) and genus Fagus L. (Fagaceae) using fossil, morphological, and molecular data /." [S.l. : s.n.], 2005. http://deposit.ddb.de/cgi-bin/dokserv?idn=974014982.
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Krob, Florian [Verfasser], and Ulirch A. [Akademischer Betreuer] Glasmacher. "The Neoproterozoic to recent evolution of SW Gondwana - From an orogen to a passive continental margin environment induced by the "plate" and "plume mode". / Florian Krob ; Betreuer: Ulirch A. Glasmacher." Heidelberg : Universitätsbibliothek Heidelberg, 2020. http://d-nb.info/1218599421/34.
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He, Amaranth Wei. "Model evolution." Thesis, McGill University, 2006. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=98721.
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"Model Driven Software Development" is a recent trend in development of software-intensive systems. In the Model Driven Software Development process, all knowledge pertaining to the software system to be built is represented in the form of models, in the right formalism(s) and at the right level of abstraction. At the highest level of abstraction, domain models, rather than generic models are used. Although the idea of developing the software system at a higher abstraction level is appealing, many fundamental questions remain unresolved. Many issues such as how to define the syntax and semantics of models, how to represent and store models and how to trace model evolution should be addressed properly. In this thesis, the focus is on model transformations and the open problems related to it. In particular, how to compare models, how to trace model evolution (with as a goal to undo and redo model changes), how to deal with meta-model evolution, and ultimately with semantics evolution are explored. For each issue, we analyze problems, and propose some solutions. We use small case studies to make issues more concrete. All case studies are developed in AToM3 (A Tool for Multi-formalism and Meta-Modeling), developed in the Modeling, Simulation and Design Lab (MSDL) in the School of Computer Science of McGill University.
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Cordonnier, Marie-Michèle. "Application de l'immunochimie a l'etude des proprietes du phytochrome, recepteur de la photomorphogenese chez les plantes." Paris 6, 1987. http://www.theses.fr/1987PA066316.
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Le phytochrome, chromoproteine, sert de photorecepteur pour une vaste gamme de reponses developpementales des plantes a la lumiere, existe sous deux formes interconvertibles par la lumiere. Des techniques immunologiques, en particulier la technologie des anticorps monoclonaux, se sont reveles tres utiles pour determiner les relations entre structure et fonction de la chrmoproteine: les differences entre le phytochrome inactif (pr) et le phytochrome actif (pfr), les domaines moleculaires conserves, potentiellement importants pour le mode d'action du pigment et l'existence de populations multiples de phytochrome pouvant jouer des roles differents dans la morphogenese
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ELGADI, MOHAMMED. "Elaboration et evolution en temperature de l'alliage amorphe tb::(65)cu::(35) : etude de l'ordre atomique a courte et moyenne distance et de l'ordre magnetique existant a basse temperature en relation avec le mode d'elaboration." Paris 6, 1986. http://www.theses.fr/1986PA066398.
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L'alliage est obtenu par pulverisation cathodique ou par trempe ultrarapide, et l'etat amorphe est tres stable. Mesure par diffraction de neutrons des distances entre premiers voisins. Mise en evidence d'une grande coordinence entre les atomes de pb et faible autour des atomes de cu. Observation de bulles de tb disposees en ruban ayant a basse temperature une forte aimantation. Entre les bulles, il existe des fluctuations de concentration et d'aimantation. Analyse microstructurale de l'alliage
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Fuchs, Alexander Tinelli C. "Evolving model evolution." [Iowa City, Iowa] : University of Iowa, 2009. http://ir.uiowa.edu/etd/361.
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Fuchs, Alexander. "Evolving model evolution." Diss., University of Iowa, 2009. https://ir.uiowa.edu/etd/361.
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Automated theorem proving is a method to establish or disprove logical theorems. While these can be theorems in the classical mathematical sense, we are more concerned with logical encodings of properties of algorithms, hardware and software. Especially in the area of hardware verification, propositional logic is used widely in industry. Satisfiability Module Theories (SMT) is a set of logics which extend propositional logic with theories relevant for specific application domains. In particular, software verification has received much attention, and efficient algorithms have been devised for reasoning over arithmetic and data types. Built-in support for theories by decision procedures is often significantly more efficient than reductions to propositional logic (SAT). Most efficient SAT solvers are based on the DPLL architecture, which is also the basis for most efficient SMT solvers. The main shortcoming of both kinds of logics is the weak support for non-ground reasoning, which noticeably limits the applicability to real world systems.
The Model Evolution Calculus (ME) was devised as a lifting of the DPLL architecture from the propositional setting to full first-order logic. In previous work, we created the solver Darwin as an implementation of ME, and showed how to adapt improvements from the DPLL setting. The first half of this thesis is concerned with ME and Darwin. First, we lift a further crucial ingredient of SAT and SMT solvers, lemma-learning, to Darwin and evaluate its benefits. Then, we show how to use Darwin for finite model finding, and how this application benefits from lemma-learning.
In the second half of the thesis we present Model Evolution with Linear Integer Arithmetic (MELIA), a calculus combining function-free first-order logic with linear integer arithmetic (LIA). MELIA is based on ME and supports similar inference rules and redundancy criteria. We prove the correctness of the calculus, and show how to obtain complete proof procedures and decision procedures for some interesting classes of MELIA's logic. Finally, we explain in detail how MELIA can be implemented efficiently based on the techniques employed in SMT solvers and Darwin.
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Frisch, Walter. "Co-Evolution of Information Revolution and Spread of Democracy. 33. Jahrestagung der Gesellschaft für Informatik an der Johann Wolfgang Goethe-Universität in Frankfurt am Main 29.9. - 2.10. 2003." Gesellschaft für Informatik, 2003. http://epub.wu.ac.at/3209/1/CO%2DEvolution%2DWFRISCH.pdf.
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This is a short summary of a recent survey [FR03] focusing on the observed evidence, that Internet connectivity is positively correlated with spread of democracy at high levels of significance. The results of multivariate correlation analysis and probabilities regression estimate models are based on the combined analysis of mid - 1991's, to 2001 data series of the Eurostat's and US Census
Bureau, the World Bank, and OECD's statistical data service which track the growth of information technology and rating of freedom and democracy worldwide.(author's abstract)
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Hardin, Thomas J. 1988. "Kinetic metallic glass evolution model." Thesis, Massachusetts Institute of Technology, 2018. http://hdl.handle.net/1721.1/120206.
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Thesis: Ph. D., Massachusetts Institute of Technology, Department of Materials Science and Engineering, 2018.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 213-227).
The structure of metallic glass controls its mechanical properties; this structure can be altered by thermomechanical processing. This manuscript presents a model for this structural evolution of metallic glass under thermal and mechanical stimuli. The foundation of this model is a potential energy landscape; this consists of three pieces: a function for the energy of any given stable state, a density of states function across the landscape, and a model for the energetic barriers between stable states. All three of these pieces are parameterized in terms of the configurational potential energy of the glass, which is split into isochoric and dilatative degrees of freedom. Under a thermal or mechanical stimulus, the glass traverses the potential energy landscape by way of isotropic relaxation or excitation events, and by shear transformations. The rates of these events are calculated using transition state theory. This model is first implemented in homogeneous form, treating the glass nanostructure as a statistical distribution; this implementation, while devoid of spatial detail, is nonetheless able to fit many of the experimental results on homogeneous flow previously in the literature. The second implementation of the model is in a mesoscale discrete shear transformation zone dynamics framework; this couples the model's rate equations to discrete points in a finite element model under realistic thermomechanical loading, and propagates the effects of local events via static elasticity. Emphasis is placed on efficient computer implementation of the new model's physics, improving on the previous state of the art with stiffness matrix factor caching and geometric multigrid methods. These numerical improvements produce a 200x speedup over previous algorithms, enable rapid simulations of glass with evolving elastic properties, and facilitate the first-ever metallic glass simulations of physical nanomechanical experiments with matching length and time scales.
by Thomas James Hardin.
Ph. D.
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Chouli, Souad. "Structures optiques dissipatives en cavité laser à fibre." Phd thesis, Université de Bourgogne, 2011. http://tel.archives-ouvertes.fr/tel-00692049.
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Cette thèse concerne l'étude de la dynamique des structures optiques dissipatives observées dans une cavité à gestion de dispersion utilisant l'évolution non linéaire de la polarisation comme technique de blocage de modes. Nous avons montré expérimentalement l'existence d'une transition graduelle entre le régime de fonctionnement continu et le régime de fonctionnement multi-impulsionnel. Nous nous sommes intéressés à l'état intermédiaire où il nous a été possible d'obtenir divers régimes inédits et d'étudier ainsi le comportement collectif des solitons dissipatifs en présence d'un fond continu. La dynamique de "la pluie de solitons" est une manifestation complexe et fascinante constituée de trois composantes de champ : le fond continu, les solitons de dérive et la phase condensée. Elle s'accompagne d'une circulation d'énergie à travers ces trois composantes. Le mouvement relatif des solitons de dérive ainsi que l'asymétrie temporelle présentent les caractéristiques majeures qui distinguent cette dynamique des autres. D'autres types d'auto-organisation ont été observés et étudiés, comme "le relargage des solitons de la phase condensée" ou bien encore "la vobulation du train de solitons". Nous nous sommes intéressés aussi à la propagation d'une seule impulsion dans la cavité. Pour la première fois, une importante dynamique de respiration spectrale a été prédite dans une cavité à gestion de la dispersion. Nous avons montré qu'une compression temporelle de l'impulsion est accompagnée d'un élargissement spectral d'une grande ampleur dans la partie passive de la cavité et que la largeur de l'impulsion peut dépasser la largeur de la bande passante du milieu amplificateur. Nous avons étudié la dynamique de la respiration spectrale, l'extraction et l'optimisation du signal laser en fonction des paramètres de la cavité et nous avons présenté les caractéristiques d'une cavité qui permet la génération d'une impulsion dont sa largeur spectrale est supérieure à la largeur de la bande passante de l'amplificateur d'un facteur de 2.4. Les dynamiques présentées dans cette thèse témoignent de la complexité et de la richesse de la dynamique dissipative des lasers à fibre fonctionnant en régime de blocage de modes passif par évolution non linéaire de la polarisation.
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Lin, Yuehua. "A model transformation approach to automated model evolution." Birmingham, Ala. : University of Alabama at Birmingham, 2007. http://www.mhsl.uab.edu/dt/2007p/lin.pdf.
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Dukkipati, Ambedkar. "ACE-Model: A Conceptual Evolutionary Model For Evolutionary Computation And Artificial Life." Thesis, Indian Institute of Science, 2002. http://hdl.handle.net/2005/47.
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Darwinian Evolutionary system - a system satisfying the abstract conditions: reproduction with heritable variation, in a finite world, giving rise to Natural Selection encompasses a complex and subtle system of interrelated theories, whose substantive transplantation to any artificial medium let it be mathematical model or computational model - will be very far from easy. There are two motives in bringing Darwinian evolution into computational frameworks: one to understand the Darwinian evolution, and the other is to view Darwinian evolution - that carries out controlled adaptive-stochastic search in the space of all possible DNA-sequences for emergence and improvement of the living beings on our planet - as an optimization process, which can be simulated in appropriate frameworks to solve some intractable problems. The first motive led to emerging field of study commonly referred to as Artificial Life, and other gave way to emergence of Evolutionary Computation, which is speculated to be the only practical path to the development of ontogenetic machine intelligence. In this thesis we touch upon all the above aspects.
Natural selection is the central concept of Darwinian evolution and hence capturing natural selection in computational frameworks which maintains the spirit of Darwinian evolution in the sense of conventional, terrestrial and biological perspectives is essential. Naive models of evolution define natural selection as a process which brings in differential reproductive capabilities in organisms of a population, and hence, most of the evolutionary simulations in Artificial Life and Evolutionary Computation implement selection by differential reproduction: the Attest members of the population are reproduced preferentially at the expense of the less fit members of the population. Formal models in evolutionary biology often subdivide selection into components called 'episodes of selection' to capture the different complex mechanisms of nature by which Darwinian evolution can occur. In this thesis we introduce the concept of 'episodes of selection' into computational frameworks of Darwinian evolution by means of A Conceptual Evolutionary model (ACE-model). ACE-model is proposed to be simple and yet it captures the essential features of modern evolutionary perspectives in evolutionary computation framework.
ACE-model is rich enough to offer abstract and structural framework for evolutionary computation and can serve as a basic model for evolutionary algorithms. It captures selection in two episodes in two phases of evolutionary cycle and it offers various parameters by which evolutionary algorithms can control selection mechanisms. In this thesis we propose two evolutionary algorithms namely Malthus evolutionary algorithms and Malthus Spencer evolutionary algorithms based on the ACE-model and we discuss the relevance of parameters offered by ACE-model by simulation studies.
As an application of ACE-model to artificial life we study misconceptions involved in defining fitness in evolutionary biology, and we also discuss the importance of introducing fitness landscape in the theories of Darwinian evolution.
Another important and independent contribution of this thesis is: A Mathematical Abstraction of Evolutionary process. Evolutionary process is characterized by Evolutionary Criteria and Evolutionary Mechanism which are formalized by classical mathematical tools. Even though the model is in its premature stage to develop any theory based on it, we develop convergence criteria of evolutionary process based on this model.
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Kögel, Maximilian [Verfasser]. "Operation-based Model Evolution / Maximilian Kögel." München : Verlag Dr. Hut, 2011. http://d-nb.info/1016531532/34.
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Keller, Benjamin J. "An algebraic model of software evolution." Thesis, This resource online, 1990. http://scholar.lib.vt.edu/theses/available/etd-03122009-040841/.
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Bleu, Josefa. "Étude expérimentale et intégrative des coûts et bénéfices de la viviparité chez le lézard vivipare." Phd thesis, Université Pierre et Marie Curie - Paris VI, 2011. http://tel.archives-ouvertes.fr/tel-00687672.
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La viviparité, qui consiste à mettre au monde directement des jeunes vivants, a évolué de nombreuses fois à partir de l'oviparité, qui consiste à pondre des oeufs, en particulier chez les lézards et les serpents (les squamates). Ce groupe est celui où l'on observe le plus grand nombre d'évolutions indépendantes de la viviparité, ainsi que des évolutions récentes et à des niveaux taxonomiques faibles. Le lézard vivipare est une des rares espèces au sein de laquelle l'oviparité et la viviparité coexistent. J'ai donc utilisé cette espèce pour mon étude sur les coûts et les bénéfices de la viviparité. Je me suis d'abord intéressée aux ajustements de l'investissement dans la reproduction ainsi qu'aux coûts de la gestation. J'ai observé une absence d'ajustement post-ovulatoire de la taille de portée, de la masse de portée et de la masse du jeune. Cependant, j'ai montré que les femelles ajustent ces paramètres en fonction de leur environnement pendant la vitellogenèse, ainsi qu'en fonction de leur corpulence et de leur date de mise bas de l'année passée. J'ai ensuite étudié les coûts de la gestation de manière expérimentale, en contrôlant les accouplements, en manipulant la taille de portée, et en comparant des femelles ovipares à des femelles vivipares. Ces études ont mis en évidence, selon le contexte, des effets de la gestation sur le système immunitaire, sur le comportement de thermorégulation, sur l'endurance, et sur la perte de poids des femelles ; mais pas d'effet sur leur survie après la mise bas. L'étude comparative a montré que les coûts de la reproduction sont plus importants pour les femelles ovipares que les vivipares avant la gestation. Par ailleurs, la gestation est une période non seulement associée à des coûts mais aussi à des effets maternels. J'ai montré que la croissance des jeunes après la naissance dépend de la taille de portée pendant la gestation. Cependant, comme c'est souvent le cas, le mécanisme de cet effet maternel n'est pas connu. Afin de mettre en évidence les facteurs à l'origine des effets maternels, j'ai développé une approche expérimentale qui repose sur l'incubation in vitro d'embryons de lézards vivipares. Les résultats préliminaires sont prometteurs étant donné que ce processus permet d'obtenir des jeunes vivants. Finalement, j'ai montré l'existence d'effets de l'âge grand-maternel chez les lézards vivipares. Il s'agit de la première mise en évidence d'effets de l'âge grand-maternel en populations naturelles.
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Garza, Núñez Dagoberto. "An industry evolution model incorporating strategic interaction." Diss., Georgia Institute of Technology, 2002. http://hdl.handle.net/1853/30753.
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Rambidis, Anastasios X. "Security issues for the software evolution model." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1998. http://handle.dtic.mil/100.2/ADA346067.
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Thesis (M.S. in Computer Science) Naval Postgraduate School, March 1998."March 1998." Thesis advisor(s):, Bert Lundy, LuQu. Includes bibliographical references (p. 101-102). Also available online.
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Dubb, Lindsey. "A likelihood model of gene family evolution /." Thesis, Connect to this title online; UW restricted, 2005. http://hdl.handle.net/1773/10264.
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Avogadro, di Collobiano Simone. "Tangled Nature : a model on ecological evolution." Thesis, Imperial College London, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.271963.
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Blackburne, Benjamin P. "Functional model proteins : structure, function and evolution." Thesis, University of Nottingham, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.405144.
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Luchetti, Andrea <1976>. "Evolution of repetitive DNA in model arthropods." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2007. http://amsdottorato.unibo.it/338/.
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