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Oberai, Amit. "Protein evolution in the membrane environment." Diss., Restricted to subscribing institutions, 2009. http://proquest.umi.com/pqdweb?did=1970613561&sid=1&Fmt=2&clientId=1564&RQT=309&VName=PQD.
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Chunco, Amanda Joan Pfennig Karin S. "Evolution in the context of the environment." Chapel Hill, N.C. : University of North Carolina at Chapel Hill, 2009. http://dc.lib.unc.edu/u?/etd,2550.
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Thesis (Ph. D.)--University of North Carolina at Chapel Hill, 2009.<br>Title from electronic title page (viewed Oct. 5, 2009). "... in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the Department of Biology." Discipline: Biology; Department/School: Biology.
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Just, Dennis William. "The Influence of Environment on Galaxy Evolution." Diss., The University of Arizona, 2012. http://hdl.handle.net/10150/265357.
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We study the influence of environment on galaxy evolution by focusing on two galaxy types known for their connection to dense environments, S0s and Brightest Cluster Galaxies (BCGs). Our goal is to identify the mechanisms responsible for the properties of galaxies in groups and clusters. We first examine the effects of environment on S0 formation over the past ~7 Gyr by tracing the increasing S0 fraction in clusters at two mass scales. We find the build-up of S0s driven by groups/clusters with velocity dispersions σ ≲ 750 km s⁻¹, suggesting mechanisms that operate most efficiently via slow encounters (e.g., mergers and tidal interactions) form S0s.With less-massive halos identified as the site for S0 formation, we test whether another route to S0 formation exists, not in isolated groups but rather in a system of four merging groups (SG1120). We place limits on how recent the S0s in that system could have formed, and finding no star formation, conclude they formed ≳ 1 Gyr prior to SG1120's current configuration, when they were in more isolated groups. We next explore cluster outskirts to constrain the number of infalling galaxies that need to be transformed and whether that process has already begun. We find the red fraction of infalling galaxies is elevated relative to the field, and that red galaxies are more clustered than blue ones, a signature of "pre-processing". We disentangle the relative strength of global versus local environment on galaxy transformation by comparing the correlation of red fraction with radius and local density. We find that both parameters are connected with the red fraction of galaxies. Finally, we measure the frequency of galaxies falling into the cluster that are bright enough to supplant the current BCG and compare the results to models. We find in ~ 85% of our clusters that the BCG is secure and remains in its priviledged state until z ~ 0.From these analyses, we find that intermediate density environments (groups and cluster outskirts) are the key site to forming S0 galaxies, and that BCGs, while not exclusively a cluster phenomenon, are well established by the redshifts we explore.
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Samani, Pedram. "Experimental evolution of yeast in a deteriorating environment." Thesis, McGill University, 2010. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=95196.
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The rapid pace of anthropogenic global change threatens global biodiversity and the integrity of ecosystems. It is now paramount to understand how organisms can adapt to these changes. Here, I review the literature on the genetic nature of stress responses in Drosophila and bacteria. Then I test how yeast populations adapted to a particular stressor, salt, can resist related stressors which they have not experienced in their recent past, freezing and sorbitol. We found that lines adapted to high salinity did not show increased resistance to sorbitol and freezing. Finally, again with yeast subjected to high salinity, I exposed populations to extremely stressful and continually deteriorating conditions to investigate how adaptation occurs. We found that beneficial mutations started to spread at intermediate stress intensities. We also found that larger populations adapt more rapidly to stress, both because they possess more beneficial mutations and because these mutations have a larger effect on growth. This research will help us understand how population can avoid extinction through adaptation and continues to stress the importance of maintaining large population to allow species survival in a changing environment.<br>Les changements anthropogéniques menacent la biodiversité et l'intégrité des écosystèmes à une échelle globale. Il est donc maintenant essentiel de comprendre comment les êtres vivants peuvent s'adapter à ces changements. Ici, je commence par présenter l'état de la recherche concernant la réponse génétique de la drosophile et des bactéries à l'imposition d'un stress. Je montre ensuite comment j'ai testé la capacité de croitre d'une population adapté à un stress donné, le sel, quand ces populations sont soumis à des stress similaires, la congélation et le sorbitol. J'ai constaté que l'adaptation au sel ne confère pas une plus grande résistance à la congélation ou au sorbitol. Finalement, encore avec la levure soumise à des conditions salées, j'ai exploré comment les populations s'adaptent à un stress important qui augmente continuellement. J'ai découvert que les mutations avec un effet bénéfique prenaient de l'importance dans la population à des niveaux de stress intermédiaires. J'ai aussi découvert que les populations plus nombreuses s'adaptaient plus rapidement parce qu'elles avaient un plus grand nombre de mutations à effet bénéfique et qu'en plus, l'effet de ces mutations était plus grand dans ces grandes populations. Ces recherches nous informent sur le processus d'adaptation et rendent clair une raisons de plus pour laquelle une grande population augmente les chances de survies de l'espèce dans un environnement changeant.
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Sköld, Emmy. "Evolution of flowering time in a changing environment." Thesis, Uppsala universitet, Institutionen för biologisk grundutbildning, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-451311.
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How come the same species of plants can naturally occur under various conditions in different parts of the world? A plant's ability to adapt in response to a changing climate hinges on the presence of genetic variation in traits, such as flowering phenology. In this study, I examine whether flowering start varies genetically within populations and compare this variation to differences between populations. This study quantifies genetic variation in flowering time in two Italian populations of Arabidopsis thaliana whilst using two Swedish populations as a reference. This was done using a randomized block design where plants were grown in a controlled climate. To characterize and measure flowering phenology, time of bolting and flowering were recorded. The experiment included four populations, a total of 150 maternal lines, and 2980 plants. One-way ANOVAs conducted separately by population indicated significant among-line variation in the two Italian populations. Flowering time differed between the Italian and Swedish populations, but not between the two Italian populations. More data would be needed to draw conclusions about the among-line variation in the Swedish populations. The results indicate that the Italian populations have the potential to respond to selection on flowering time, which is a likely consequence of a changing climate.
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Wood, Richard. "Structural evolution of environment and economy in Australia." Thesis, The University of Sydney, 2009. http://hdl.handle.net/2123/5329.
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The purpose of this research is to help understand the key relationships in an evolving economic structure that are driving resource use and greenhouse gas emissions in Australia. The approach involves looking at the factors and relationships that underpin economic growth in Australia. This research seeks to understand the changes in these factors by taking a historical perspective to the determinants of environmental impact through an investigation of structural changes over a period of 30 years. A detailed model is developed using the macro-economic tool of input-output analysis. This model makes it possible to investigate inter-relationships and intra-relationships between sectors of the environment, the economy and the population at disparate scales.
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Wood, Richard. "Structural evolution of environment and economy in Australia." University of Sydney, 2009. http://hdl.handle.net/2123/5329.
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Doctor of Philosophy (PhD)<br>The purpose of this research is to help understand the key relationships in an evolving economic structure that are driving resource use and greenhouse gas emissions in Australia. The approach involves looking at the factors and relationships that underpin economic growth in Australia. This research seeks to understand the changes in these factors by taking a historical perspective to the determinants of environmental impact through an investigation of structural changes over a period of 30 years. A detailed model is developed using the macro-economic tool of input-output analysis. This model makes it possible to investigate inter-relationships and intra-relationships between sectors of the environment, the economy and the population at disparate scales.
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Malavasi, Nicola <1987>. "The Role of the Environment in Galaxy Evolution." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2016. http://amsdottorato.unibo.it/7760/1/malavasi_nicola_tesi.pdf.
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Although the general picture of how galaxies have formed and evolved through cosmic time is already in place, still many details are missing. An example is represented by the role of environment in determining their observed properties. Local environment has been thoroughly explored through observations at low redshift and it has recently started to being investigated also in the distant Universe. Moreover, general attention has been increasingly focused on the cosmic web.
This work explores how environment is observationally related to galaxy properties such as their stellar mass, their star-formation activity, or the presence of AGN phenomena in a large redshift range (0.2 < z < 3). To perform this study, both spectroscopic redshift data sets as well as photometric redshift surveys have been deployed.
The picture that emerges is that high-density environments are favored places for galaxy evolution, showing an enhanced fraction of massive galaxies which have stopped forming stars. Galaxies in high-density environments have an increased probability of hosting radio-AGNs (belonging to the ensemble of processes that turn off the star-formation in massive galaxies) and these effects are visible since the start of the decline in the cosmic star-formation history. Large-scale structures, such as the filaments of the cosmic web, have also a role in shaping galaxy evolution and they may represent key places for the pre-processing of galaxies before they enter higher density regions such as the cluster or group environment.
As an increasing amount of observational evidence on the relation between the evolution of galaxies and their environment is gathered, a complete solution to the problem of how the local galaxy population has evolved approaches, and the history of galaxies from their formation at the dawn of time to the present day gets closer to being traced.
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Meggett, David C. "Evolution of rescue : personnel recovery for a new environment /." Thesis, Monterey, Calif. : Naval Postgraduate School, 2007. http://bosun.nps.edu/uhtbin/hyperion-image.exe/07Dec%5FMeggett.pdf.
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Thesis (M.S. in Defense Analysis)--Naval Postgraduate School, December 2007.<br>Thesis Advisor(s): Gustaitis, Peter J. "December 2007." Description based on title screen as viewed on January 23, 2008. Includes bibliographical references (p. 51-54). Also available in print.
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Luther, David A. Wiley R. Haven. "The evolution of communication in a complex acoustic environment." Chapel Hill, N.C. : University of North Carolina at Chapel Hill, 2008. http://dc.lib.unc.edu/u?/etd,1636.
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Thesis (Ph. D.)--University of North Carolina at Chapel Hill, 2008.<br>Title from electronic title page (viewed Sep. 16, 2008). "... in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the Curriculum of Ecology." Discipline: Ecology; Department/School: Ecology.
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Dusi, Eike. "Experimental Host-Parasite Co-Evolution in a Changing Environment." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-199218.
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Parasites with exclusive vertical transmission from host parent to offspring are an evolutionary puzzle. Any fitness costs for infected hosts risk the selective elimination of these parasites because their fitness is linked to host reproduction. One of the main evolutionary transitions from parasitism towards beneficial or mutualistic associations may therefore encompass a change from horizontal transmission to vertical transmission. In this thesis, the experimental evolution study on Paramecium and Holospora supports this hypothesis. The parasite nearly entirely lost horizontal transmission capacity in a treatment favouring vertical transmission and low virulence. However, many vertically transmitted parasites e.g. Caedibacter taeniospiralis impose detectable costs to their hosts. This endosymbiont imposes context-dependent costs to its host Paramecium tetraurelia. Fitness of infected paramecia was reduced in resource-limited conditions at all experimentally tested temperatures (16-32°C).
These universal fitness costs along the temperature gradient necessitate universal cost compensation that can be the ‘killer trait’ that eliminates uninfected competitors. At acute heat stress the loss of infection indicates that cost compensation is impossible, thereby restricting conditions for parasite persistence. Surprisingly, the parasite persists in permanent stress and optimal temperature conditions. Caedibacter was able to adapt to high temperature conditions by increasing its number in the populations but without reducing virulence in high temperature conditions. Acute and intense stress harms the parasite and causes its extinction but the parasite was able to evolve and adapt to stress conditions. Moreover, the parasite reacts exactly in the opposite direction as it was expected. They do not suffer from stressful conditions, they benefit.
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Testa, Charl Rudolph. "Urban memory and the evolution of the urban environment." Master's thesis, University of Cape Town, 2009. http://hdl.handle.net/11427/17125.
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An individual's connection to the world is facilitated by memory as it envelops every feature of human experience. In the absence of memory, meaning collapses. In architectural terms, if memory exists as the foundation upon which meaning is built, if a person is to find and experience meaning in their built environment, architecture must necessarily engage its temporality. The focus of this project is architecture's peculiar mnemonic capacity as it relates to memory and place. Associated themes are explored through theoretical, technological and design components. Included here are brief descriptions of the three components. The purpose of the technology and theory components was to test and develop my understanding of the dynamics of memory in the built environment and the implications of these dynamics for design and thought about architecture. Conclusions and discoveries then materialise in a design proposition.
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Štangl, Rastislav. "Procurement application solutions in cloud environment, evolution and trends." Master's thesis, Vysoká škola ekonomická v Praze, 2013. http://www.nusl.cz/ntk/nusl-199230.
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The goal of the presented thesis is to screen market and to assess the Procurement application solutions provided in cloud with focus on SMB companies. Understanding of Procurement process is base for identification of key functions and requirements on Procurement applications. Market research results in initial high level picture about the Procurement applications available with attention to cloud. Procurement applications assessment determines conclusions on market evolution and trends. The first part of the thesis introduces theoretical background of Procurement process and cloud computing. This part is completed by the list of key functions and requirements, of expected benefits, and of the steps that are important during assessment and selection of Procurement application in business. The second part investigates the Procurement application market and vendors. The screening is oriented on application features, client set, delivery models, and on other characteristics. Eight Procurement application solutions were selected for detailed assessment: Bellwether ePMX, Compleat Spend Control, Coupa, eBid eXchange, Ion Wave Technologies, PurchaseControl, Trade Interchange (ARCUS), and Xtenza. Assessment of the applications results in comparative data that are presented in predefined structure. The primary focus is on application features and Procurement functions supported. Other important evaluation categories are delivery models, security, underlying infrastructure, approval workflows, and commercials. Communication with application vendors contributed to the assessment. This part is finalized with evolution and trend conclusions focusing on cloud proliferation dynamics, and on forecast of new application functions and features that will result in new business benefits.
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ANNUNZIATELLA, MARIANNA. "Environment-driven evolution of galaxies in CLASH-VLT clusters." Doctoral thesis, Università degli Studi di Trieste, 2016. http://hdl.handle.net/11368/2908070.
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The analysis of data from recent large spectroscopic and photometric surveys has shown that galaxy properties have a bimodal distribution (e.g., Kauffmann et al. 2003). Two main populations of galaxies can be identified, the bulge-dominated, high-mass, red galaxies with low star formation rate (SFR), and the disk-dominated, low-mass, blue, and high-SFR galaxies. Blue galaxies are the dominant population at high redshifts and in low-density environments, while red galaxies take over at lower redshifts and in high-density environments. One of the key question in this context is whether these correlations are intrinsic of the galaxy populations from their formation epoch (’nature’ hypothesis) or they are the result of an environment- driven evolution (’nurture’ scenario). In this context, the analysis of galaxy popu- lations in massive clusters, characterized by the highest number densities in the Universe, is an ideal tool to shed some light on galaxy evolution, since clusters offer rather extreme physical conditions for the galaxies they host.
My work has been focused on investigating the mechanisms which drive the evolu- tion of galaxies in clusters from the Cluster Lensing And Supernova survey with Hubble (CLASH; http://www.stsci.edu/ postman/CLASH/Home.html, P.I.: M. Postman) sample and, more specifically, in the subsample of clusters with spectro- scopic follow-up from the CLASH-VLT survey (P.I.: P. Rosati) in the redshift range z ∼ 0.2 − 0.5,. These spectroscopic data are complemented by wide-field images obtained with Subaru in five photometric bands (B, V, R, I and z) and by Hubble Space Telescope ACS and WFC3 observations in 16 optical/IR bands in the central regions of clusters.This thesis is organized as follows.
In Chapter 2 I present the data used in this thesis. In particular I introduce the CLASH survey and its follow-up survey, CLASH-VLT. I describe how I derived the galaxy properties used in this work, focusing in particular on the data available for two of the CLASH clusters: MACS1206-0847 (hereafter M1206) and Abell 209 (here- after A209) .
In Chapter 3 I focus on how the environment shapes the galaxy stellar mass function in the higher redshift cluster M1206. I also compare the number, stellar and total density profiles in this cluster. By combining these informations, I set con- straints on the evolutionary processes at work in M1206.
In Chapter 4 I analyze the distribution of galaxy stellar masses and the mass density profiles in the cluster Abell 209 at lower redshift than M1206. I also study some properties of the ICL in A209, in order to shed some light on which processes form the ICL and what type of galaxies are its progenitors.
To investigate further the evolution of galaxies in A209, I also carry out the dynam- ical analysis of the orbits of passive galaxies.
To discriminate between different quenching mechanisms into shaping the evolu- tion of galaxies in this cluster, I also analyze the distribution of galaxy sizes.
In Chapter 5 I summarize the results obtained in the two clusters and draw my conclusion on which are the main processes that shape galaxy evolution on how they depend on redshift.
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Calvi, Rosa. "Groups of galaxies: a key environment for galaxy evolution." Doctoral thesis, Università degli studi di Padova, 2012. http://hdl.handle.net/11577/3422550.
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Galaxy groups are the most common structure in the universe and, as they span a wide range in local density, showing properties which range from cluster-like to field-like represent the ideal place to investigate galaxy evolution. In particular, on these scales can be active fundamental pre-processes responsible of galaxy transformations; thus, they can have a profound effect on the overall galaxy population since about 50% of all galaxies are in groups by z ~ 0. The aim of the thesis has been to explore the properties of galaxies in groups and to understand whether and how they vary as function of global environment in which they reside. In this thesis I first present the construction and the characteristics of a new catalog of groups and galaxies representative of the general field population at low redshift, the Padova Millennium Galaxy and Group Catalogue (PM2GC). The group building method used to identify galaxy groups is based on a Friends-of-Friends algorithm which takes advantage of two available quantities in observational galaxy catalogs: the projected separation in the sky and the velocity difference in the redshift space. Non-group galaxies were subdivided into “binary” systems of two bright close companions, and “single” galaxies with no companion, in order to identify different environments useful scientific analysis. I compared galaxy groups properties with those of more isolated galaxies in other environments in PM2GC and with cluster galaxies from the WIde-field Nearby Galaxy cluster Survey (WINGS). I performed a morphological analysis studying the relation between morphology and mass among single, binaries, group and cluster galaxies. I found a very smooth trend of all morphological types with environment except for S0 galaxies in clusters. Moreover, I shown that the morphological fraction depends strongly on galaxy stellar mass at very high masses. Finally, I investigated the galaxy stellar mass function (MF) to understand if the observed variations in the galaxy morphology can be explained by the dependence of the galaxy mass itself on environment. I found that at low redshift, contrary to expectations, the mass function of general field is indistinguishable from that of galaxy clusters while the difference becomes evident only considering lowest mass haloes, i.e. single galaxies. I also found indication that there is a dependence of the upper mass limit of samples on environment with the most massive galaxies only hosted by the most massive haloes. All these results represent a very important indications that not only stellar mass but also the environment in which a galaxy resides play a role in galaxy evolution. Moreover, they highlight that exist a cluster specific effect which acts on the classes of spirals and S0s galaxies since a significant number of S0s in clusters has a different origin with respect to S0s in other environments. This means that S0 population in clusters probably are closely related to spiral one<br>I gruppi di galassie sono le strutture pi ù comuni nell’universo e, poiché abbracciano una vasta gamma di densità locali mostrando proprietà che si estendono da quelle tipiche degli ammassi a quelle tipiche del campo, rappresentano il luogo ideale per indagare l’evoluzione delle galassie. In particolare, i pre-processi responsabili delle trasformazioni delle galassie possono avvenire su queste scale; per tale motivo, essi possono avere un profondo effetto sulla popolazione complessiva di galassie in quanto pi ù del 50 per cento di tutte le galassie dell’universo oggi sono in gruppi. Lo scopo della tesi è stato quindi quello di esplorare le proprietà delle galassie nei gruppi e capire se e come esse variano in funzione dell’ambiente in cui risiedono. In questa tesi presento innanzitutto la costruzione e le caratteristiche di un nuovo catalogo di gruppi e di galassie rappresentativo della popalazione di campo a basso redshift, il Padova Millennium Galaxy and Group Catalog (PM2GC). Il metodo utilizzato per identificare i gruppi di galassie si basa sull’algoritmo ”Friends-of-Friends” che sfrutta due quantità disponibili nei cataloghi osservativi delle galassie: la separazione proiettata nel cielo e la differenza di velocità nello spazio dei redshift. Le galassie che non risultano essere membri dei gruppi sono state suddivise in galssie appartenenti a sistemi ”binari” costituiti da due oggetti vicini molto luminosi e galassie ”singole” senza alcun compagno, al fine di identificare diversi ambienti utili per l’analisi scientifica. Ho confrontato le proprietà delle galassie nei gruppi con quelle di galassie più isolate appartenenti ad altri ambienti nel catalogo PM2GC e con galassie di ammasso prese dalla WIde-field Nearby Galaxy cluster Survey (WINGS). Ho quindi eseguito un’analisi morfologica studiando la relazione tra morfologia e massa tra le galassie singole, binarie, di gruppo e di ammasso. Ho trovato un andamento molto regolare in funzione dell’ambiente per tutti i tipi morfologici fatta eccezione per le galassie S0 negli ammassi. Inoltre, ho mostrato che la frazione morfologica dipende fortemente dalla massa delle galassie soprattutto per masse molto grandi. Infine, ho esaminato la funzione di massa stellare delle galassie (MF) per capire se le variazioni che abbiamo osservato nelle proprietà morfologiche delle galassie possono essere spiegate dalla dipendenza della massa stessa della galassia dall’ambiente. Ho scoperto che a basso redshift, contrariamente alle aspettative, la funzione di massa delle galassie di campo è indistinguibile da quella degli ammassi di galassie e tale differenza diventa evidente solo considerando aloni con masse pi ù basse, vale a dire le galassie singole. Ho anche trovato indicazione che vi è una dipendenza del limite di massa superiore dei diversi campioni di galassie dall’ambiente con le galassie pi ù massicce che sono ospitate dagli aloni più massicci. Tutti questi risultati ci danno importanti indicazioni che non solo la massa stellare ma anche l’ambiente in cui esse risiedono gioca un ruolo nell’evoluzione delle galassie. Inoltre, essi evidenziano che esiste un effetto specifico degli ammassi di galassie che agisce esclusivamente sulle classi di galassie S0 e spirali poiché un numero significativo di galassie S0 negli ammassi ha un’origine diversa rispetto alle S0 in altri ambienti. Questo significa che probabilmente la popolazione di galassie S0 negli ammassi è strettamente collegata a quella delle spirali
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Montanier, Jean-Marc. "Environment-driven Distributed Evolutionary Adaptation for Collective Robotic Systems." Thesis, Paris 11, 2013. http://www.theses.fr/2013PA112033/document.
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Cette thèse décrit une partie du travail effectué dans le cadre du projet européen Symbrion 1 . Ce projet vise à la réalisation de tâches complexes nécessitant la coopération de multiples robots dans un cadre de robotique en essaim (au moins 100 robots opérant ensemble). De multiples problèmes sont étudiés par le projet dont : l’auto-assemblage de robots en structures complexes et l’auto-organisation d’un grand nombre de robots afin de réaliser une tâche commune. Le principal sujet porte sur les mécanismes d’auto-adaptation pour la robotique modulaire et en essaim, avec un intérêt pour des capacités de forte coordination et de coopération à l’échelle de l’essaim.Les difficultés rencontrées dans la réalisation de ce projet sont dues à l’utilisation de robots dans des environnements ouverts restant inconnus jusqu’à la phase de déploiement. Puisque les conditions d’opérations ne peuvent être prédites à l’avance, des algorithmes d’apprentissage en ligne doivent être utilisés pour élaborer les comportements utilisés. Lorsqu’un grand nombre de robots sont utilisés, plusieurs considérations doivent être prise en compte : capacité de communication réduite, faible mémoire, faible capacité de calcul. Par conséquent les algorithmes d’apprentissage en ligne doivent être distribués à travers l’essaim.De multiples approches ont déjà été proposées pour faire face aux problèmes posés par l’apprentissage en ligne décentralisé de comportements robotiques, parmi lesquels la robotique probabiliste, l’apprentissage par renforcement, et la robotique évolutionnaire. Cependant, le problème abordé dans le cadre de cette thèse se caractérise par le fait que l’on considère un groupe de robots (en lieu et place d’un seul et unique robot). De plus, dû à la nature ouverte de l’environnement, il n’est pas possible de supposer que l’ingénieur humain ait les connaissances nécessaires pour définir les éléments indispensables aux processus d’apprentissage.Assurer l’intégrité de l’essaim est placé en tant que premier élément d’une feuille de route visant à définir un ensemble d’étapes nécessaires à la réalisation d’une tâche par un groupe de robot dans un environnement ouvert :– Étape 1 : Assurer l’intégrité de l’essaim.– Étape 2 : Maintenir les robots disponibles en tant que service à l’utilisateur.– Étape 3 : Réaliser la tâche définie par l’utilisateur.Dans le cadre de cette thèse nous travaillons à la réalisation de l’étape 1 de cette feuille de route, et assumons l’hypothèse de travail suivante :Hypothèse de travail : Dans un cadre de robotique collective en environnement ouvert, la réalisation d’une tâche définie par l’utilisateur implique tout d’abord un comportement auto-adaptatif.Le sujet de cette thèse est la réalisation de solutions algorithmiques décentralisées pouvant garantir l’in- tégrité d’un essaim de robots en environnement ouvert lorsque un système robotique collectif utilise une communication locale. La principale difficulté à sa résolution est le besoin de prendre en compte l’envi- ronnement. En effet, en fonction de l’environnement courant, les robots peuvent avoir à démontrer une grande variété de comportements à l’échelle globale comme la coopération, la spécialisation, l’altruisme, ou la division du travail.Dans cette thèse nous introduisons et définissons le problème de l’Adaptation Evolutionnaire Distribuée Guidée par l’Environnement. Nous proposons un algorithme pour résoudre ce problem. Cet algorithme a été validé aussi bien en simulation que sur des robots réels. Il a été utilisé pour étudier le problème de l’auto-adaptation dans les environnements suivants :– Environnement où l’émergence de consensus comportementaux est nécessaire.– Environnements où la robustesse face à des changements environnementaux est nécessaires.– Environnements où des comportements altruistes sont nécessaires<br>Cette thèse décrit une partie du travail effectué dans le cadre du projet européen Symbrion 1 . Ce projet vise à la réalisation de tâches complexes nécessitant la coopération de multiples robots dans un cadre de robotique en essaim (au moins 100 robots opérant ensemble). De multiples problèmes sont étudiés par le projet dont : l’auto-assemblage de robots en structures complexes et l’auto-organisation d’un grand nombre de robots afin de réaliser une tâche commune. Le principal sujet porte sur les mécanismes d’auto-adaptation pour la robotique modulaire et en essaim, avec un intérêt pour des capacités de forte coordination et de coopération à l’échelle de l’essaim.Les difficultés rencontrées dans la réalisation de ce projet sont dues à l’utilisation de robots dans des environnements ouverts restant inconnus jusqu’à la phase de déploiement. Puisque les conditions d’opérations ne peuvent être prédites à l’avance, des algorithmes d’apprentissage en ligne doivent être utilisés pour élaborer les comportements utilisés. Lorsqu’un grand nombre de robots sont utilisés, plusieurs considérations doivent être prise en compte : capacité de communication réduite, faible mémoire, faible capacité de calcul. Par conséquent les algorithmes d’apprentissage en ligne doivent être distribués à travers l’essaim.De multiples approches ont déjà été proposées pour faire face aux problèmes posés par l’apprentissage en ligne décentralisé de comportements robotiques, parmi lesquels la robotique probabiliste, l’apprentissage par renforcement, et la robotique évolutionnaire. Cependant, le problème abordé dans le cadre de cette thèse se caractérise par le fait que l’on considère un groupe de robots (en lieu et place d’un seul et unique robot). De plus, dû à la nature ouverte de l’environnement, il n’est pas possible de supposer que l’ingénieur humain ait les connaissances nécessaires pour définir les éléments indispensables aux processus d’apprentissage.Assurer l’intégrité de l’essaim est placé en tant que premier élément d’une feuille de route visant à définir un ensemble d’étapes nécessaires à la réalisation d’une tâche par un groupe de robot dans un environnement ouvert :– Étape 1 : Assurer l’intégrité de l’essaim.– Étape 2 : Maintenir les robots disponibles en tant que service à l’utilisateur.– Étape 3 : Réaliser la tâche définie par l’utilisateur.Dans le cadre de cette thèse nous travaillons à la réalisation de l’étape 1 de cette feuille de route, et assumons l’hypothèse de travail suivante :Hypothèse de travail : Dans un cadre de robotique collective en environnement ouvert, la réalisation d’une tâche définie par l’utilisateur implique tout d’abord un comportement auto-adaptatif.Le sujet de cette thèse est la réalisation de solutions algorithmiques décentralisées pouvant garantir l’in- tégrité d’un essaim de robots en environnement ouvert lorsque un système robotique collectif utilise une communication locale. La principale difficulté à sa résolution est le besoin de prendre en compte l’envi- ronnement. En effet, en fonction de l’environnement courant, les robots peuvent avoir à démontrer une grande variété de comportements à l’échelle globale comme la coopération, la spécialisation, l’altruisme, ou la division du travail.Dans cette thèse nous introduisons et définissons le problème de l’Adaptation Evolutionnaire Distribuée Guidée par l’Environnement. Nous proposons un algorithme pour résoudre ce problem. Cet algorithme a été validé aussi bien en simulation que sur des robots réels. Il a été utilisé pour étudier le problème de l’auto-adaptation dans les environnements suivants :– Environnement où l’émergence de consensus comportementaux est nécessaire.– Environnements où la robustesse face à des changements environnementaux est nécessaires.– Environnements où des comportements altruistes sont nécessaires
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Farkas, Alex Miklós. "Program construction and evolution in a persistent integrated programming environment /." Title page, contents and abstract only, 1995. http://web4.library.adelaide.edu.au/theses/09PH/09phf229.pdf.
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Bamford, Steven Peter. "The evolution of massive disc galaxies with environment and redshift." Thesis, University of Nottingham, 2006. http://eprints.nottingham.ac.uk/10200/.
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This thesis examines the evolution of massive disc galaxies as a function of cosmic time and environment by analysing a sample of luminous disc galaxies, located in the field and rich clusters at intermediate redshifts. The data utilised for this study are two-dimensional optical spectra obtained with the FORS2 instrument on the VLT, along with imaging from a variety of sources. From these we measure absolute rest-frame B-band magnitudes, stellar scalelengths (r_d,phot), rotation velocities (V_rot), emission-line scalelengths (r_d,spec) and emission-line equivalent widths, resulting in estimates of gas-phase oxygen abundance, current star formation rate (SFR) and dust extinction. We investigate evolution of the field Tully-Fisher relation (TFR) using a sample of 89 galaxies covering the redshift range 0.1-1. We find evidence that these luminous spiral galaxies are increasingly offset from the local TFR with redshift, reaching a brightening of -1.0+-0.5 mag, at a given V_rot, by z ~ 1. We argue that, due to likely selection effects, this observed evolution represents an upper limit. Previous studies have used an observed correlation between TFR residuals and V_rot to argue that low mass galaxies have evolved significantly more than those with higher mass. However, we demonstrate that such a correlation does not necessarily indicate a physical difference in the evolution of galaxies with different V_rot. Interpreting the luminosity evolution derived from the TFR as due to evolution in the SFR of these luminous spiral galaxies, we find that SFR(z) is proportional to (1+z)^(1.7+-1.1). Although the uncertainties are large, this evolution, which is probably an upper limit, appears to be slower than that derived for the overall field galaxy population. This suggests that the rapid evolution of the SFR density of the universe observed since z ~ 1 is not in general driven by the evolution of the SFR in individual bright spiral galaxies. The measured emission-line equivalent widths, diagnostic ratios, oxygen abundances, star formation rates and dust extinctions for a sample of 40 luminous, massive (V_rot > 80 km/s), star-forming, field disc galaxies, with redshifts z=0.2-0.8, cover similar ranges to those observed across a large sample of local galaxies. However, at a given galaxy luminosity, many of our galaxies have oxygen abundances significantly lower than local galaxies with similar luminosities. The galaxies in this luminous, metal-poor subsample exhibit physical conditions similar to those of local faint and metal-poor star-forming galaxies. Lower-metallicity systems are ~2 mag brighter, and have star formation rates an order of magnitude higher, compared with similar metallicity galaxies today. Oxygen abundances are not found to correlate with the emission scale length size of galaxies, and the rotation velocity--metallicity relation, while perhaps present, is unclear. This suggests that massive field galaxies at intermediate redshifts are diverse in terms of their interstellar gas properties and stellar content. To examine variations in the TFR with environment, matched samples of 58 field and 22 cluster galaxies are constructed, selected in a homogeneous manner and covering similar ranges in redshift (0.25 < z < 1.0) and luminosity (M_B < -19.5 mag). The distributions of M_B, V_rot and scalelength are found to be comparable for the two samples. However, we find that the TFR of the cluster galaxies is systematically offset with respect to the field sample by -0.7+-0.2 mag. This offset is significant at 3-sigma and persists when we account for an evolution of the field TFR with redshift. Tests are performed to investigate potential differences in the observed emission lines and derived parameters of the cluster and field samples. However, no such differences which could account for the offset are found. Offsets are also found between cluster and field samples in the relations of M_B and V_rot versus r_d,phot and r_d,spec, although these are difficult to interpret. Our cluster galaxies are found to have ratios of emission-line to stellar scalelengths (r_d,spec / r_d,phot) significantly lower than for our field galaxies: 0.88 +- 0.08 versus 1.15 +- 0.05, respectively. This indicates that star formation is more centrally concentrated in the cluster galaxies. The comparison of interstellar gas properties between 16 bright, star-forming, cluster disc galaxies at intermediate redshifts (0.3 < z < 0.6, <z> = 0.42) and their counterparts in the coeval field, reveals that both samples are generally similar. However, on average the cluster galaxies have emission-line equivalent widths that are significantly lower than for the field galaxies. A contrasting fraction of the distant cluster galaxies, though, appears to have much higher emission-line equivalent widths, comparable to the highest seen in the field. This tentatively implies a bimodality in the star formation rates per unit luminosity of distant cluster galaxies, which is not present for our field sample. However we find no substantial difference in the long term star formation histories of these cluster and field galaxies, as indicated by their gas-phase metallicities. The most likely explanation for the results of our cluster versus field comparison is that spiral galaxies entering intermediate-redshift clusters often experience a short-lived enhancement of their star formation rate, followed by a decline, which we would expect to be accompanied by a transformation to S0 morphology.
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Qutieshat, Enas M. "Traditional contract law in the electronic environment : evolution or revolution?" Thesis, University of Aberdeen, 2010. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=158831.
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This thesis will examine issues related to the formation and validity of electronic contracts on a comparative basis between the English, American and UNCITRAL approaches. When examining the English approach, reference will be made to relevant EC Directives in relation to the subject matter. This thesis has four main objectives. First, to assess the impact of using electronic communication tools to reach agreement. Second, to identify some key points that should be considered when examining the formal validity of electronic contracts. Third, to establish a foundation for having a valid contract in which rights and obligations could arise accordingly. Finally, this thesis aims to identify whether the traditional contract law rules are able to meet the challenges that are brought by the use of electronic communication tools, or whether they require reform. It will be noticed throughout that electronic contracts come in different types. This leads to difficulty with introducing one rule to cover all types of electronic contracts. Furthermore, some concerns arise when electronic communication tools are used to form contracts as to the exact time of contracting. Other concerns arise when trying to fulfil some legal formalities such as writing and signature. This is because of the special and dual nature of electronic data and the possibility of using different types of signature methods in cyberspace. Finally, it is important to consider taking steps to update some of the current contract law rules to work alongside the electronic technology revolution. Some aspects of the traditional contract law rules become challenging when applied to electronic contracts. For example, the issues of contract formation and the use of electronic and intelligent software require direct attention when considering the issue of e-contracts. The reference to such challenging well-established contract law rules is necessary throughout this thesis, however, since the current rules which deal with electronic commerce in general and electronic contracts in particular do not cover all the issues that are related to electronic contracts. Lastly, this thesis will sound the alarm on the need to raise the legal awareness of both online users and website developers when contracting online. <i>Chapter Two</i> will assess the use of electronic communication tools to form such contracts, and the sorts of problems that could arise as a consequence. <i>Chapter Three</i> will highlight whether or not electronic contracts can be considered written and signed when the law imposes such requirement. This chapter will also seek to determine whether there is a need for such formalities in cyberspace. <i>Chapter Four</i> is designed to deal with selected issues of material validity of electronic contracts. This chapter is essential when considering all types of electronic contracts, including formal ones. It will consider issues that are related to mutual assent in cyberspace, and the problems that could arise with web-based contracts in relation to these.
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Chalasani, Pallavi. "Engineering for evolution of a Software to a Production Environment." The Ohio State University, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=osu1398952564.
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Ross, Caroline Ann. "Life-history strategies of primates." Thesis, University College London (University of London), 1989. http://discovery.ucl.ac.uk/1349897/.
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This thesis examines variation in the life-history parameters of primates using comparative techniques. Several theories of life-history evolution are introduced in the first chapter, together with a summary of the previous work on this topic. Scaling methods are used to separate variation in life-history parameters that is correlated with body weight from that which cannot be predicted from an animal's size. These methods are described in detail in Chapter 2. Chapter 3 describes the variation found in body size and basal metabolic rate and correlations with phylogeny, diet, habitat and other aspects of ecology. Patterns of variation in reproductive parameters, particularly reproductive rates (as measured by the intrinsic rate of natural increase, r_{max}) and reproductive effort (as measured by prenatal and postnatal infant growth rates), are described and compared with patterns reported in other studies. Possible reasons for the scaling relationships found are suggested and the influences of metabolic rate, phylogeny, diet, habitat and other aspects of ecology are investigated. This is carried out for all primates in Chapters 4-6 and in Chapter 7 there is a closer look at the cercopithecine monkeys. It is suggested that r_{max} is influenced by the predictability of the environment, with more unpredictable environments being associated with a higher r_{max} that more predictable environments. However, this is only found when body weight effects are removed from the r_{max} data. Growth rates do not appear to be correlated with environmental predictability but are mainly correlated with body size and relative metabolic rate. There is some indication that the degree of parental care may also be correlated with relative growth rates. It is concluded that no single theory of life-history evolution can amount for the variation found in primate life-histories, but that some aspects of several theories may be useful in describing the patterns found.
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Boussau, Bastien. "Evolution Profonde et Phylogénie." Phd thesis, Université Claude Bernard - Lyon I, 2008. http://tel.archives-ouvertes.fr/tel-00345743.
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Durant cette thèse je me suis intéressé à l'évolution profonde du vivant, depuis le dernier ancêtre commun universel (LUCA) jusqu'aux ancêtres des trois grands royaumes, les Archées, les Bactéries et les Eucaryotes. J'ai notamment cherché à placer quelques organismes dans l'arbre de la vie, tels que la bactérie Aquifex aeolicus et l'archée Cenarchaeum symbiosum, et j'ai également étudié l'évolution des températures de croissance il y a plusieurs milliards d'années. Pour ce faire, j'ai développé des algorithmes afin de reconstruire l'évolution de séquences géniques, puis j'ai utilisé ces séquences pour prédire les températures optimales de croissances d'organismes aujourd'hui éteints. Mes collègues et moi-même estimons que LUCA ne vivait pas à très haute température, mais que ses directs descendants les ancêtres des Bactéries et du groupe comprenant les Archées et les Eucaryotes vivaient dans des environnements plus chauds. Cela signifie que les deux lignées venant de LUCA ont subi le même type d'évolution en parallèle, qui pourrait avoir été causée par une seule et même pression de sélection. Cette pression pourrait être le résultat d'un intense bombardement météoritique il y a 3.8 milliards d'années, et avoir été accompagnée d'un changement depuis un génome à ARN pour LUCA vers des génomes à ADN pour ses descendants. Ensuite, dans la lignée des Bactéries, les températures optimales de croissance ont chuté, ce qui pourrait correspondre à l'évolution de la température des océans au cours des 3.5 derniers milliards d'années.
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Hallsson, Lára R. "Quantitative Trait Evolution in a Changing Environment in a Seed Beetle." Doctoral thesis, Uppsala universitet, Zooekologi, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-159284.
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During the last decades the climate has been changing more rapidly than in the preceding periods. This is for instance characterized by an increase in temperature. Interestingly, such changes in the environment are not necessarily constant over time as they often show high levels of fluctuation. Organisms are exposed to these changes and respond to them and a recent theoretical model predicts that fluctuations in the environment are important for populations’ response to climate change. The aim of this thesis is to investigate how populations respond to a changing environment, including fluctuations. My thesis is based on the previously mentioned theoretical model and I used a suite of laboratory experiments on the seed beetle Callsosobruchus maculatus, to test the model predictions in a quantitative genetic framework. First, I assessed the genetic architecture of several life history and morphological traits in order to verify that there is sufficient additive genetic variation for the population to respond to changes in the environment. Second, I tested the detailed model predictions explicitly, by investigating whether different types of environmental fluctuations matter for a population’s response. Third, I investigated changes in quantitative genetic variation after i) a rapid shift in temperature and ii) long term selection under increasing temperature including fluctuations. Fourth, I concentrated on sex differences in response to temperature, and finally, I assessed the relative importance of genetic and nongenetic inheritance for traits that differ in their plastic response to a change in the environment. I found that environmental fluctuations are highly important for a population’s response to environmental change. I could detect changes in a set of quantitative genetic parameters, suggesting that a population’s potential to respond to selection, environmental sensitivity and the evolution of phenotypic plasticity are affected by the selective past. I also found that sexes differ in additive genetic variation and plasticity and that parental effects may play an important role in the evolutionary process. Therefore, future studies would benefit greatly from considering details of the selective past and especially environmental fluctuations during attempts to predict how populations respond to a changing environment, particularly with regards to climate change.
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Jaffe, Yara Lorena. "The formation and evolution of galaxies as a function of environment." Thesis, University of Nottingham, 2012. http://eprints.nottingham.ac.uk/12453/.
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This thesis investigates the role of environment on galaxy formation and evolution, giving particular focus to the transformation of star forming spirals into passive S0s. The data utilised for this study comes from photometric and spectroscopic observations of galaxies at 0 < z < 1 in different environments from the ESO Distant Cluster Survey. We first study the formation history of (172) cluster ellipticals (Es) and S0s, the oldest types of galaxies in the local universe. We examine their colour-magnitude relation (CMR), and find a very small intrinsic colour scatter. Only 7% of the galaxies are significantly bluer than the CMR. The scarcity of blue S0s indicates that, if they are the descendants of spirals, these were already red when they became S0s. We observe no dependence of the CMR scatter with z or cluster velocity dispersion. This implies that by the time cluster E/S0s achieve their morphology, the vast majority have already joined the red sequence. We estimate the galaxy formation redshift z_F for each cluster and find that while it does not depend on the cluster velocity dispersion, it increases weakly with cluster redshift. This suggests that, at any given z, in order to have a population of fully-formed E and S0s they needed to have formed most of their stars ≃2–4Gyr prior to observation. In other words, the galaxies that already have early-type morphologies also have reasonably-old stellar populations. This is partly a manifestation of the "progenitor bias", but also a consequence of the fact that the vast majority of the E/S0s in clusters (in particular the massive ones) were already red by the time they achieved their morphology. Moreover, E and S0 galaxies exhibit very similar colour scatter, implying similar stellar population ages. We also find that fainter E/S0s finished forming their stars later, consistent with the cluster red sequence being built over time and the brightest galaxies reaching the red sequence earlier than fainter ones. Finally, we find that the E/S0s cluster galaxies must have had their star formation truncated over an extended period ∆t ≿1 Gyr. We then move our focus to the evolution of star-forming galaxies. We investigate the effect of the environment on the transformation of star-forming spirals into passive S0s by studying the properties of the gas and the stars in a sample of 422 emission-line galaxies in different environments. We identify galaxies with kinematical disturbances (in their gas disks), and find that they are more frequent in clusters than in the field. The fraction of kinematically-disturbed galaxies increases with cluster velocity dispersion and decreases with distance from the cluster centre, but remains constant with projected galaxy density. We also studied morphological disturbances in the stellar light, finding that the fraction of morphologically disturbed galaxies is independent of environment. Moreover, there is little correlation between the presence of kinematically-disturbed gas and morphological distortions. For the kinematically-undisturbed galaxies, we find that the cluster and field B-band Tully-Fisher relations are remarkably similar. Additionally, we find that the kinematically-disturbed galaxies show a suppressed specific star formation rate. There is also evidence indicating that the gas disks in cluster galaxies have been truncated, and therefore their star formation is more concentrated than in low-density environments. If spirals are the progenitors of cluster S0s, our findings imply that the physical mechanism transforming cluster galaxies efficiently disturbs the star forming gas and reduces their specific star formation rate. This star-forming gas is either removed more efficiently from the outskirts of the galaxies or it is driven towards the centre (or both). In any case, this makes any remaining star formation more centrally concentrated, helping to build the bulges of S0s. All this evidence, together with the fact that the transformation mechanism does not seem to induce strong morphological disturbances on the galaxies, suggests that the physical processes involved are related to the intracluster medium, with galaxy-galaxy interactions playing only a limited role in clusters. Interestingly, in analogy with the "blue" early-type galaxies found in the CMR study in clusters, we have also found several emission-line E/S0 galaxies with extended rotating star-forming gas disks.
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Penny, Samantha J. "The origin and evolution of dwarf galaxies in the cluster environment." Thesis, University of Nottingham, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.537633.
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Johnson, Sarah Stewart. "Mars in the late Noachian : evolution of a habitable surface environment." Thesis, Massachusetts Institute of Technology, 2008. http://hdl.handle.net/1721.1/45605.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 2008.<br>This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.<br>Includes bibliographical references.<br>This dissertation addresses whether simple life forms might have existed on Mars during the late Noachian epoch, and whether those life forms, or their traces, can be detected today. It begins by analyzing the ancient Martian climate in light of new evidence that sulfur chemistry played a prominent role in the planet's early evolution. It finds that sulfur-induced greenhouse warming could have periodically heated the planet enough to support liquid water, thereby creating warm, wet, clement conditions. Moreover, it finds that those warming pulses, while short-lived over geologic time, may have persisted for hundreds of years. If sulfur helped create environmental conditions capable of hosting life, however, it also created conditions that were adverse to sustaining it. In particular, dissipation of sulfur volatiles cooled the climate, and sulfur rainout contributed to the acidity of Martian surface waters. The dissertation therefore proceeds to analyze the potential for persistence and detection of life in terrestrial environments with Mars-like characteristics. It first investigates the potential for detecting ancient life by searching for lipid biomarkers in sulfur-rich acid salt lakes, concluding that a variety of biomarkers may be more resistant to decay than previously believed. It then analyzes soil samples from permafrost, discovering the oldest independently authenticated viable organisms ever found, and positing low-level metabolic activity and DNA repair as a survival mechanism in ancient cells. Finally, the dissertation uses deep sequencing to examine prokaryotic diversity in a terrestrial Mars-like river characterized by low pH and high concentrations of iron and sulfur, with results considered in light of the implications for life detection approaches incorporating new, in situ "PCR in a chip" technology. The dissertation concludes by proposing future work, including the ultimate goal of developing a life detection instrument for Mars.<br>by Sarah Stewart Johnson.<br>Ph.D.
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Yeh, Pamela Jean. "Evolution of a bird population following establishment in a novel environment /." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2004. http://wwwlib.umi.com/cr/ucsd/fullcit?p3142459.
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Fraguio, Gisela. "A programming environment for the reuse and evolution of abstract models." FIU Digital Commons, 1989. https://digitalcommons.fiu.edu/etd/3407.
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The PEREAM system is a software engineering environment that supports the design and implementation of object-oriented software components. Software development in the system is accomplished by the continuous evolution of a concept from an early specification to a final implementation. PEREAM supports the ability to incrementally specify software components. It provides for the reusing, browsing, and editing of the software components at any stage of their development history.
Concepts in the PEREAM system are modeled with a uniform data structure. The development of the software components is maintained in a graph structure. The concepts are manipulated using the Smalltalk-80 Class Browser or the PEREAM GRAPHICAL EDITOR.
This thesis describes the concepts and design behind the PEREAM system and the PEREAM MODELING TECHNIQUE. It also discusses the design and implementation of a graphical editor for the PEREAM environment which manipulates the software components graphically.
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CAVALLARI, Nicola. "EVOLUTION OF THE CIRCADIAN CLOCK IN EXTREME ENVIRONMENT: LESSONS FROM CAVEFISH." Doctoral thesis, Università degli studi di Ferrara, 2010. http://hdl.handle.net/11392/2389352.
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Evolution has been strongly influenced by the daily cycles of temperature and light imposed by the rotation of the Earth. Fascinating demonstrations of this are seen in extreme environments such as caves where some animals have remained completely isolated from the day-night cycle for millions of years. Most of these species show convergent evolution, sharing a range of striking physical properties such as eye loss. One fundamental issue is whether “hypogean” species retain a functional circadian clock. This highly conserved, physiological timing mechanism allows organisms to anticipate daily environmental changes and is synchronized primarily by light. The Somalian cavefish, Phreatichthys andruzzii does possess a circadian clock that is entrained by a daily regular feeding time but strikingly, not by light. Under constant conditions the P. andruzzii clock oscillates with an extremely long period and also lacks normal temperature compensation. We document multiple mutations affecting a light-induced clock gene, Period2 as well as the genes encoding the extra-retinal photoreceptors Melanopsin (Opn4m2) and TMT-opsin. Remarkably, we show that ectopic expression of zebrafish homologs of these opsins rescues light induced clock gene expression in P. andruzzii cells. Thus, by studying this natural mutant we provide direct evidence for a peripheral light-sensing function of extra-retinal opsins in vertebrates. Furthermore, the properties of this cavefish illustrate that evolution in constant darkness leads not only to anatomical changes but also to loss of gene function linked with the detection and anticipation of the day-night cycle.
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Pracy, Michael Benjamin Physics Faculty of Science UNSW. "The properties and evolution of galaxy populations in the rich cluster environment." Awarded by:University of New South Wales. Physics, 2006. http://handle.unsw.edu.au/1959.4/23033.
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This thesis is concerned with the role the rich cluster environment plays in the evolution of its galaxy population. We approach this issue from two angles, first we use deep wide-field imaging to investigate the effect of the cluster environment on the spatial and luminosity distribution of galaxies. Secondly, we focus on one particularly interesting class of galaxy, the enigmatic E+A galaxies, using a combination of state-of-the-art telescopes and novel instrumentation to elucidate the physical mechanisms and environmental influences causing the rapid change in star-formation activity in these galaxies. We present results from a deep photometric study of the rich galaxy cluster Abell 2218 (z=0.18) based on Hubble Space Telescope images. These have been used to derive the cluster luminosity function to extremely faint limits. We find the faint-end slope of the luminosity function to vary with environment within the cluster - in the sense that the ratio of `dwarf' galaxies to `giant' galaxies increases in the lower-density outskirt regions. Using imaging obtained with the Isaac Newton Telescope (INT) we confirm the presence of luminosity segregation in Abell 2218. However, luminosity segregation in clusters does not appear to be ubiquitous, with two other clusters studied with the INT (A119 at z=0.04 and A2443 at z=0.11) showing no sign of luminosity segregation of their galaxy populations. We use integral field spectroscopy of a sample of E+A galaxies in intermediate redshift clusters, obtained with the FLAMES system on the European Southern Observatory's VLT and the GMOS instrument on Gemini-North, to determine the radial variation in the strength of Hdelta absorption in these galaxies, and hence map out the distribution of the recently formed stellar population. We find a diversity of behaviour amongst these galaxies in terms of the radial variation in Hdelta absorption: with gradients that are either negative, flat, or positive. By comparing with numerical simulations we suggest that the first of these different types of radial behaviour provides evidence for a merger/interaction origin, whereas the latter two types of behaviour are more consistent with the truncation of star formation in normal disk galaxies.
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Miner, Benjamin G. "Evolution of phenotypic plasticity insights from echinoid larvae /." Connect to this title online, 2003. http://purl.fcla.edu/fcla/etd/UFE0001450.
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Perry, Elizabeth. "Gene, Organism and Environment: Understanding Patterns of Genome Evolution in Bacteria and Bacteriophage." Thesis, University of Oregon, 2013. http://hdl.handle.net/1794/13275.
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For my dissertation research, I used a model system of bacteria and bacteriophage to study patterns of genome evolution. I performed whole-genome sequencing of replicate populations to determine the genetic changes responsible for a repeatable pattern of coevolution between bacteria and phage. I found that genetic changes conferring resistance in bacteria negatively impacted other traits such as growth rates and sensitivity to antibiotic. Different resistance mutations varied in the magnitude of their pleiotropic costs, and this resulted in a fixation bias favoring mutations that minimized pleiotropic effects. I manipulated the environment and found that differential pleiotropy between environments drove repeatable evolution at different genetic scales. Finally, I explored theoretically how bacteria, phage, and resource interact through a dynamic system of feedbacks. I used a mathematical model to describe priority effects in evolution, where the expected fate of a beneficial mutation varies depending upon whether it appears before or after a competing mutation.<br>10000-01-01
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Marcello, Angelica. "Contemplating the evolution of attachment and cognition in a collaborative learning environment." Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2006. http://wwwlib.umi.com/cr/ucsd/fullcit?p3213074.
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Thesis (Ph. D.)--University of California, San Diego, 2006.<br>Title from first page of PDF file (viewed June 26, 2006). Available via ProQuest Digital Dissertations. Vita. Includes bibliographical references (p. 192-213).
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Bergman, Elisabeth Anne, and Elisabeth Anne Bergman. "Conquering the terrestrial environment: the evolution of xylem anatomy in early tracheophytes." Thesis, The University of Arizona, 2017. http://hdl.handle.net/10150/626731.
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Since the first land plants appeared 480-360 million years ago, natural selection has resulted in continued colonization into increasingly drier and harsher environments. The evolution of traits associated with water transport and avoidance of embolisms allowed plants to conquer increasingly more seasonal and drier terrestrial environments. However, it is unclear just how the xylem anatomy of the first Embryophytes differed from extant (living) taxa and if these differences translated to differences in plant functioning. I measured and compared hydraulic traits from stem cross-sections from extant plants and extinct fossil specimens. For 231 stems comprising 115 extant and 116 extinct taxa, measures of xylem conduit diameter/frequency and segment diameter were measured. Comparing these measures of xylem conductive traits indicates that extant plants, for their size, have more and wider conduits leading to a larger total conductive area and higher rates of water conductance. Further, the combination of xylem traits found in extinct paleo plants suggests that they were less efficient at water transport and likely more restricted to less seasonal and more wet environments. Together, these results reveal a unique insight into the functioning of extinct paleo plants and the evolution of xylem form and function.
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Seth, Anil Kumar. "On the relations between behaviour, mechanism, and environment : explorations in artificial evolution." Thesis, University of Sussex, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.340800.
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Wilkins, Helen. "The evolution of the built environment : complexity, human agency and thermal performance." Thesis, The University of Sydney, 2006. https://hdl.handle.net/2123/29246.
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The thermal environments created by buildings provide the context within which social life operates. Adjustable built environments generate diverse thermal conditions. That is, they possess the thermal capacity to produce enhanced levels of thermal choices and thermal control. Classes and assemblages of buildings that generate diverse thermal environments will increase the range of social options that the building milieu can accommodate, compared with less adjustable classes and assemblages, because they are more readily able to accommodate changing social options and circumstances. A relationship therefore exists between the thermal operational adjustability (combining thermal choices and thermal control) associated with classes of buildings and the capacity for operational adjustability possessed by communities. This means that a class of building or an assemblage of buildings, eg. a ‘pueblo’ form, that provides a highly adjustable milieu is more likely to be occupied for longer periods of time, because it can accommodate more internal social changes prior to undergoing a system—level alteration into a different class of building or settlement. Conversely, an inflexible building milieu is more likely to be occupied for shorter periods of time prior to a system-level alteration, in which change will be observed in the class of building or settlement.
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Christlein, Daniel. "Disentangling luminosity, morphology, star formation, stellar mass, and environment in galaxy evolution." Diss., The University of Arizona, 2004. http://hdl.handle.net/10150/280595.
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We present a study of the photometric and spectroscopic properties of galaxies in a sample of six nearby, rich galaxy clusters. We examine the variations of fundamental galaxy properties, such as luminosity, morphology, and star formation rates with environment, providing new constraints on the mechanisms that drive the evolution of galaxies. This study also introduces a new maximum likelihood algorithm to recover the true distribution function of galaxies from an incomplete sample. This algorithm is ideally suited for modern-day surveys that gather a large amount of information about each object. The R-band luminosity function (GLF) shows no variation among clusters or between the field and clusters, with the exception of an enhancement of the luminous tip of the GLF in clusters. However, the GLF of quiescent galaxies steepens significantly between the field and clusters and is not universal in clusters either, suggesting that star formation properties may be more strongly correlated than the luminosity function with environment. The U-band GLF in clusters is slightly steeper than the R-band GLF, indicating that cluster galaxies are bluer at fainter magnitudes and that the GLF is thus weakly sensitive to star formation, dust, or metallicity effects. To constrain the mechanisms that shape the morphologies of cluster galaxies, we have calculated separate R-band luminosity functions for galaxy bulges and disks. Their distribution as a function of morphology and environment indicates that intermediate- and early-type galaxies can be generated from late-type galaxies by increasing the luminosity of the bulge, but not by fading the disks alone, favoring galaxy-galaxy interactions or mergers as the primary morphological transformation mechanism. Finally, we find a residual correlation of star formation with environment even after accounting for environmental variations of morphology, stellar mass, and stellar age. Thus, the star formation gradient in clusters is not just another aspect of the morphology-density relation, and cannot be solely the result of initial conditions, but must partly be due to subsequent evolution through a mechanism (or mechanisms) sensitive to environment. These results thus constitute a true "smoking gun" pointing to the effect of environment on the later evolution of galaxies.
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Ganesan, Shankaranarayanan. "Dynamic schema evolution in a heterogeneous database environment: A graph theoretic approach." Diss., The University of Arizona, 1998. http://hdl.handle.net/10150/282767.
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The objective of this dissertation is to create a theoretical framework and mechanisms for automating dynamic schema evolution in a heterogeneous database environment. The structure or schema of databases changes over time. Accommodating changes to the schema without loss of existing data and without significantly affecting the day to day operation of the database is the management of dynamic schema evolution. To address the problem of schema evolution in a heterogeneous database environment, we first propose a comprehensive taxonomy of schema changes and examine their implications. We then propose a formal methodology for managing schema evolution using graph theory with a well-defined set of operators and graph-based algorithms for tracking and propagating schema changes. We show that these operators and algorithms preserve the consistency and correctness of the schema following the changes. The complete framework is embedded in prototype software system called SEMAD (Schema Evolution Management ADvisor). We evaluate the system for its usefulness by conducting exploratory case studies using two different heterogeneous database domains, viz., a University database environment and a scientific database environment that is used by atmospheric scientists and hydrologists. The results of the exploratory case studies supported the hypothesis that SEMAD does help database administrators in their tasks. The results indicate that SEMAD helps the administrators identify and incorporate changes better than performing these tasks manually. An important overhead cost in SEMAD is the creation of the semantic data model, capturing the meta data associated with the model, and defining the mapping information that relates the model and the set of underlying databases. This task is a one-time effort that is performed at the beginning. The subsequent changes are incrementally captured by SEMAD. However, the benefits of using SEMAD in dynamically managing schema evolution appear to offset this overhead cost.
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Duivenvoorden, Steven. "Unravelling the influence of environment, redshift and confusion on the star formation in dusty galaxies." Thesis, University of Sussex, 2018. http://sro.sussex.ac.uk/id/eprint/77363/.
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Over the last three decades, the far-infrared emission from distant galaxies has been revealed to us. This far-infrared light is emitted by dust clouds heated by UV radiation from young stars. This reveals to us some of the most remarkable and highly star-forming galaxies in the Universe. The Herschel space observatory was able to capture this light. With this thesis I have attempted to get a better understanding of the underlying galaxy population. I have done this by observing the most extreme forms of star formation in the early Universe seen in maps obtained by the SPIRE instrument and using prior information from deep high resolution surveys. In particular I have examined the dependencies of dusty galaxy properties on their environment. I have confirmed that star formation is primarily dependent on both galaxy mass and whether a galaxy lies in the "blue cloud". Environment is the primary influence on the fraction of galaxies lying in the blue cloud and has a minor, but significant, affect on the average star formation rate of star forming galaxies. The highest redshift galaxies directly detected in the Herschel SPIRE maps are very rare, but due to the large area of the HerMES surveys we are able to find a statistical significant sample. With the addition of longer wavelength SCUBA-2 data I further confine the redshift of the dusty galaxies and find that the star formation rates of those sources are extremely high and exceed 1000 M_ a year. The observed number counts of these extremely bright sources have been a problem for galaxy evolution models. I am able to explain the observed number count of red SPIRE sources by adding correlated confusion noise and Gaussian instrumental noise to simulated galaxy catalogues. My results emphasise that it is crucial to correct for noise and selection effects for comparison with simulations. I exploit a novel way of fitting the full SPIRE maps using prior information from deep high resolution surveys, obtained from wavelengths ranging from optical to radio. In doing so I obtain the most accurate values of the cosmic infrared background (CIB) at the SPIRE wavelengths. With these results we have a better indication of which sources are producing the CIB, and therefore the bulk of star formation. My results indicate that future large area surveys like LSST are likely to resolve a substantial fraction of the population responsible for the CIB at 250 μm ≤ λ ≤ 500 μm.
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Rafieferantsoa, Mika Harisetry. "Neutral hydrogen in galaxies, its content and the effect of environment on its evolution." University of the Western Cape, 2018. http://hdl.handle.net/11394/6581.
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Philosophiae Doctor - PhD<br>Using two hydrodynamic galaxy formation simulations from the Mufasa project that I helped
develop, we aim to better understand the relationship between galaxy evolution and its cold gas
content commonly known as the neutral hydrogen or Hi. We first look at the environmental
properties of the simulated galaxies and compare to those that are available observationally. As
a proxy, we specifically quantify the so-called galactic conf ormity, which is the concordance
between the properties of galaxies neighbouring the primaries, in chapter 2. We show that the
Hi, the specific star formation rate (sSFR) and the colour of galaxies show galactic conformity
in qualitative agreement with previous observed data, i.e. the Hi-rich primary galaxies are surrounded
by Hi-richer galaxies than the Hi-poor primary galaxies, and similarly for the sSFR
and the colour. We find that environment, quantified by the number of neigbouring galaxies
within a fixed aperture, stellar age and molecular hydrogen (H2) also show conformity. Galactic
conformity also depends on the dark matter halo mass of the primary galaxy. The galactic
conformity signal from the primaries of smaller haloes is weak but extends out to several virial
radii of those structures, whereas the signal is very strong for high mass haloes but lowers
quickly with distances from the primaries. We also find the galactic conformity only emerges
in the later half of cosmic evolution. We next quantify the gas content and star formation
depletion timescales in chapter 3. We use two carefully chosen groups of simulated galaxies
and find that timescales are affected by both the mass of the virialised structure of the first
infall and the galaxy stellar mass at infall: the higher the halo mass or the stellar mass the
shorter the timescale. The gas or Hi depletion timescale is concordant to that of the star formation
quenching, indicative of direct decrease of SFR due to depletion of the extended cold
gas reservoir. The neutral atomic or molecular hydrogen consumption timescale depends on
the Hubble time. Galaxies tend to form stars more efficiently at lower redshift. While the halo
mass of infall affects the consumption timescale of the Hi, it does not correlate with the H2. We
lastly develop machine learning tools to use galaxy photometric data to predict a galaxy’s Hi
mass in chapter 4, to allow predictions for Hi from much larger optical photometric surveys.
The training and testing of the algorithms are done first with the simulated data from Mufasa.
We show that our model performs better than previously done with ad hoc data fitting
approaches. Random Forest (RF) followed by the Deep Neural Networks (DNN) perform best
among the explored machine learning techniques. Extending the trained models to observed
data, namely the Arecibo Legacy Fast ALFA (ALFALFA) and REsolved Spectroscopy Of a Local
VolumE (RESOLVE) survey data, we show the overall performance is slightly reduced relative
to the simulated testing set owing to the small inconsistency between definition of galaxy properties
between simulation and observational data, and DNN perfoms the best in this case. The
application of our methods is useful for galaxy-by-galaxy predictions and anticipated to correct
for incompletness in the upcoming Hi deep surveys done with MeerKAT and eventually
the Square Kilometre Array (SKA).
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Corris, Amanda B. "Organism-Environment Codetermination: The Biological Roots of Enactivism." University of Cincinnati / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1593266129358889.
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Heilmayer, Olaf. "Environment, adaptation and evolution: scallop ecology across the latitudinal gradient = Umwelt, Anpassung und Evolution: Ökologie der Jakobsmuscheln im latitudinalen Gradienten /." Bremerhaven : Alfred-Wegener-Inst. für Polar- und Meeresforschung, 2004. http://www.gbv.de/dms/bs/toc/385417098.pdf.
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Toyonaga, Yuko. "Evolution of flowering time control in response to heterogeneous environment in Arabidopsis thaliana /." View online version; access limited to Brown University users, 2005. http://wwwlib.umi.com/dissertations/fullcit/3174683.
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Levy, Lorenza Rose James A. "The effect of cluster environment on galaxy evolution in the Pegasus I Cluster." Chapel Hill, N.C. : University of North Carolina at Chapel Hill, 2007. http://dc.lib.unc.edu/u?/etd,1136.
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Thesis (Ph. D.)--University of North Carolina at Chapel Hill, 2007.<br>Title from electronic title page (viewed Mar. 27, 2008). "... in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the Department of Physics & Astronomy." Discipline: Physics and Astronomy; Department/School: Physics and Astronomy.
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Geach, James Edward. "Obscured activity and the role of environment on galaxy evolution at high redshift." Thesis, Durham University, 2007. http://etheses.dur.ac.uk/2473/.
Full textAbstract:
A significant amount of activity in the Universe is obscured by dust, produced in the final phases of stellar evolution and in the detonation of Type II supernovae. Re-processed radiation from starlight is emitted from this dust at infrared wavelengths, and this must be taken into consideration when performing surveys of star formation (and nuclear activity) in order to form an unbiased picture of galaxy evolution. It is also clear that the star formation histories of galaxies are significantly modified by their local environment, the outcome of which is the characteristic galaxy populations observed in rich clusters and in the field in the local Universe. In this thesis I examine galaxy evolution in the context of environment from z ~ 0.5 to 2 ~ 3, paying attention to obscured activity revealed by observations in the rest-frame infrared. A mid-infrared (24μm) survey of two intermediate redshift clusters reveals a population of luminous infrared galaxies (LIRGs) which are missed in optical surveys (or significantly underestimated in terms of their star formation rates). Despite there being a large difference between the number of LIRGs detected in the two clusters (likely due to varying global cluster properties controlling the survival of starbursts in the cluster environment), these could be a potentially important population of galaxies. Their large star formation rates mean that they could evolve into local passive S0s by the present day. Although the S0s must be assembled after z ~ 0.5, local clusters are also dominated by massive elliptical galaxies which are mostly already in place by z ~ 0.5, and therefore must have assembled their stellar mass at much higher redshifts (z ≥3). At z = 3.1 I examine the nature of extreme activity in a rich, primitive environment - an example of a progenitor of a rich cluster of galaxies, and therefore the likely site of formation of local massive ellipticals. A number of giant (100 kpc-scale) Lyman-α emission-line nebulae (LABs) in the SA 22 protocluster contain bright submillimeter (850μm) galaxies (SMGs). Their extremely luminous rest-frame far-infrared emission suggest very high star formation rates and/or nuclear activity. Given that a large fraction of LABs seem to contain these active galaxies, it is plausible to link LABs' formation with feedback events such as superwind outflows from starburst regions. Indeed, a weak correlation between the SMGs' bolometric luminosity and the LABs' Lya luminosities appears to suggest that SMGs are powering these extended haloes. Although feedback from active galaxies appears to be important at early times, it remains a significant factor in galaxy-environment symbiosis at all epochs. The most profound effect a galaxy can have on its surroundings is to impart energy to the surrounding medium. In clusters, this is important for preventing the cooling of baryons and therefore the truncation of star formation. I investigate the environments of four low-power (L(_1.4GHz) ≤ 10(^25) WHz (^-1)) radio galaxies in the Subaru-XMM-Newton Deep Field at z ~ 0.5. The environments are all found to be moderately rich groups, and at least one shows evidence that it is in a stage of cluster assembly via sub-group merging. The conclusion is that the radio loud active galactic nuclei are triggered by galaxy-galaxy interactions within sub-groups, prior to cluster virialisation. These radio galaxies are destined to become brightest cluster galaxies, providing a low-power, but high-duty cycle feedback on gas in high-density regions at low redshift - necessary to suppress star formation in massive ellipticals at z ~ 0. The hostility of clusters to star formation (or at least the observation that it is suppressed in the highest density regions of the local Universe) is thought to be in part responsible for the rapid decline in the global volume averaged star formation rate (SFRD) since 2 ~ 1. Tracking the evolution of the SFRD beyond z ~ 1 is hard, because optical tracers (e.g. Ha) used in the local Universe become redshifted into the near-infrared, and up until recently the cameras suitable for large surveys have not been available. I have performed the largest ever near-infrared narrowband blank field survey for Hα emission at z = 2.23. Understanding the evolution of the SFRD before its decline to the present day is essential if we are to find the 'epoch' of galaxy formation. I present the Hα luminosity function and measure the SFRD at this epoch, finding little evolution in the time between z = 1.3 and z = 2.23. This is consistent with a flattening of the SFRD, indicating that this is the peak era of star formation in the Universe, before the gradual suppression of activity during the build up of groups and clusters to the present day.
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Thomas, Michael Andrew. "Framework for Cohesive Zone Model Based Multiscale Damage Evolution in a Fatigue Environment." Wright State University / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=wright1308257790.
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Thomason, Stuart. "An architecture to support the configuration and evolution of software components in a distributed runtime environment." Thesis, Keele University, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.325857.
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Liu, Ruimin. "An agent-based service-oriented approach to evolving legacy software systems into a pervasive computing environment." Thesis, De Montfort University, 2010. http://hdl.handle.net/2086/4023.
Full textAbstract:
This thesis focuses on an Agent-Based Service-Oriented approach to evolving legacy system into a Pervasive Computing environment. The methodology consists of multiple phases: using reverse engineering techniques to comprehend and decompose legacy systems, employing XML and Web Services to transform and represent a legacy system as pervasive services, and integrating these pervasive services into pervasive computing environments with agent based integration technology. A legacy intelligent building system is used as a case study for experiments with the approach, which demonstrates that the proposed approach has the ability to evolve legacy systems into pervasive service environments seamlessly. Conclusion is drawn based on analysis and further research directions are also discussed.
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Kolwa, Sthabile. "The effects of environment on radio-loud AGN activity in Stripe 82." University of the Western Cape, 2016. http://hdl.handle.net/11394/5318.
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>Magister Scientiae - MSc<br>We investigate the link between environment and radiative accretion efficiency using a sample of 8946 radio-loud AGN detected at 1 − 2 GHz in the SDSS Stripe 82 region. We quantify their environments using the surface-density parameter, ƩN, which measures galaxy density based on distances to Nth nearest neighbours. Comparing Ʃ2 and Ʃ5 between AGN and control galaxies, we obtain relative densities that quantify the degree of galaxy clustering around each AGN. Using this, we examine the relation between density and the HERG-LERG dichotomy (accretion-modes) classified using a 1.4 GHz luminosity (L1.4GHz) threshold. Our results indicate that, in the low-redshift interval (0.1 < z < 0.2), LERGs occupy environments denser than the field. At intermediate redshifts (0.2 < z < 1.2), both LERGs and HERGs occupy regions denser than the field. Spearman’s rank tests show that correlations between density and L1.4GHz in both redshift intervals are weak. We conclude that the absence of a strong correlation is confirmation of the idea that galaxy density plays a more secondary role on AGN activity and also, accretion-mode classification (both measured using L1.4GHz). It is likely that the rate of gas accretion or properties of galactic-scale magnetic fields correlate more strongly with L1.4GHz, hence being primarily influential.<br>National Research Foundation (NRF)
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Tang, Zhiqiang, and Yue Peng. "Assessment of IxLoad in an MPG Environment." Thesis, Linköpings universitet, Institutionen för datavetenskap, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-96440.
Full textAbstract:
Long Term Evolution (LTE) is the latest mobile network technology published by the Third Generation Partnership Project (3GPP). It might become a dominant technology for the next generation and it is attract-ing a great deal of attention from the top global corporations. IxLoad is a real-world traffic emulator, designed by the test solution provider Ixia. Mobile Packet Gateway (MPG) has been developed by Ericsson and is a commercial network equipment to provide a smart interface between mobile network (Global System for Mobile Communi-cation (GSM), Wideband Code Division Multiple Access (WCDMA), LTE) and internet for operators’ network. In this thesis, MPG is utilized to assess the capacity and LTE functionality of IxLoad. Capacity estima-tion will verify the maximum simulated users that can be supported by IxLoad and will test the maximum throughput IxLoad can achieve with a particular number of simulated users, under conditions involving a particular application scenario such as browsing HTTP. In addition to Session Management some other features such as Track Area Update and Handover, Busy Hour Functionality, Deep Packet Inspection, Mul-tiple Access Point Names (APNs) and Dynamic Quality of Service Enforcement are also covered in the functionality assessment. Moreover, this thesis gives a brief introduction to Evolved Packet Sys-tem (EPS), Evolved Packet Core (EPC), and to the functionality of MPG in addition to the role of MPG in EPS. Meanwhile the newest features of IxLoad are also presented in this document. Finally, as the outcome of this thesis, several suggestions are proposed in relation to improve-ments for IxLoad and MPG.