Дисертації з теми "String landscape"

This article is the author's PhD thesis. After a review of string vacua obtained through compactification (with and wothout fluxes), it presents and describes various aspects of the Landscape of string vacua. At first it gives an introduction and an overview of the statistical study of the set of four dimensional string vacua, giving the detailed study of one corner of this set (G2-holonomy compactifications of M-theory). Then it presents the ten dimensional approach to string vacua, concentrating on the ten dimensional description of the Type IIA flux vacua. Finally it gives two examples of models having some interesting and characteristic phenomenological features, and that belong to two different corners of the Landscape: warped compactifications of Type IIB String Theory and M-theory compactifications on G2-holonomy manifolds.

The aim of Metta Vee is to explore stylistic metamorphosis in an extended cross-generic work for electroacoustic string ensemble which combines the rich vocabulary of string writing from the Western art tradition with that found in jazz, folk and rock music. In performance this is achieved by individually expressing and then fusing the associated playing styles. In a series of supporting works different aspects of cross-genre writing for strings are explored, both in scored and sonic pieces. The final composition, Metta Vee (a phonetic abbreviation of metamorphous violin) is an evolving landscape which travels through various styles whilst retaining cohesion in the overall design. It is, as expressed in the subtitle, a stylistic journey through a landscape of string. Two violin soloists, one acoustic and one electric, convey the more intricate details of stylistic fusion, exploiting the instrument’s technical capacities and broad repertoire. The electric solo part has been scored for a 5-string violin, incorporating the low viola C string in addition to the standard tuning. Opportunities for soloing and musical exchanges between the players have been designated within the main work to showcase the cross-stylistic performance aesthetic through a series of variations generated by repeated motifs. Metta Vee is a work that faces the challenge of mixing the tonal characteristics of the electric violin with the acoustic string world so the two may be not just individually showcased, but homogenized, creating a new sonority as well as stylistic fusion.

In this thesis we provide new tools to determine and explore the Landscape of four-dimensional effective field theories originating from string and M-theory. The main aim is to introduce, within four-dimensional effective descriptions, elements that are predicted from string theory. To this end, a hierarchy of forms is introduced within the four-dimensionalN=1 supergravity theories. The inclusion of gauge three-forms delivers a dynamical way to generate flux-induced superpotentials. Instead, gauge two-forms, dual descriptions of axions, may be eventually gauged by three-forms to generate a superpotential coupling between the different chiral multiplet sectors of the theory. The mutual constraints among the background fluxes, such as tadpole cancellations, are imposed by gauge four-forms. A hierarchy of objects, to which the gauge forms couple, is then introduced: four-dimensional BPS-strings, membranes and 3-branes enlarge the Landscape, allowing the background fluxes to consistently change transversing different spacetime regions. The Freed-Witten anomaly cancellations and the changing of tadpole cancellation conditions due to background sources are neatly expressed by BPS-junctions of membranes ending on strings and 3-branes ending on membranes. Membrane-mediated domain wall transitions are studied, which determine how the scalar fields flow connecting a vacuum to another of the Landscape. According to the perturbative regime that is scanned only some transitions are allowed, with a dramatic influence on the spectrum of objects that can be consistently incorporated in the four-dimensional description.

In this thesis we present a detailed analysis of the statistical properties of the type IIB flux landscape of string theory. We focus primarily on models constructed via the Large Volume Scenario (LVS) and KKLT and study the distribution of various phenomenologically relevant quantities. First, we compare our considerations with previous results and point out the importance of Kähler moduli stabilisation, which has been neglected in this context so far. We perform different moduli stabilisation procedures and compare the resulting distributions. To this end, we derive the expressions for the gravitino mass, various quantities related to axion physics and other phenomenologically interesting quantities in terms of the fundamental flux dependent quantities $g_s$, $W_0$ and $\mathfrak{n}$, the parameter which specifies the nature of the non-perturbative effects. Exploiting our knowledge of the distribution of these fundamental parameters, we can derive a distribution for all the quantities we are interested in. For models that are stabilised via LVS we find a logarithmic distribution, whereas for KKLT and perturbatively stabilised models we find a power-law distribution. We continue by investigating the statistical significance of a newly found class of KKLT vacua and present a search algorithm for such constructions. We conclude by presenting an application of our findings. Given the mild preference for higher scale supersymmetry breaking, we present a model of the early universe, which allows for additional periods of early matter domination and ultimately leads to rather sharp predictions for the dark matter mass in this model. We find the dark matter mass to be in the very heavy range $m_{\chi}\sim 10^{10}-10^{11}\text{ GeV}$.

Le paysage de la théorie des cordes est vaste et, à bien des égards, encore inexploré. Néanmoins, après compactification, il a été observé que des caractéristiques communes apparaissent, qui sont indépendantes de la compactification elle-même, et qui sont supposées être intrinsèquement liées aux effets de gravité quantique. Dans cette optique, le « Swampland program » vise à comprendre les conditions auxquelles une théorie effective des champs doit obéir afin d'être complétée de manière cohérente par la gravité quantique, pour laquelle la théorie des cordes est, à l'heure actuelle, le cadre le plus satisfaisant. Ces contraintes sont actuellement exprimées sous la forme d'une série de conjectures qui, à une énergie donnée, divisent l'espace des théories effectives en « Landscape » (à savoir, celles qui proviennent de la gravité quantique) et « Swampland » (celles qui, bien que cohérentes en tant que théories quantiques des champs, par exemple sans anomalie, ne peuvent pas être couplées de manière cohérente à la gravité quantique). Une caractéristique typique des compactifications de cordes est la présence de modules, des champs scalaires sans masse avec un potentiel plat dont le terme cinétique dans l'action de la supergravité joue le rôle d'une métrique dans l'espace paramétré par ces modules. Dans ce contexte, l'une des conjectures les plus largement acceptées, la « Distance Conjecture », stipule qu'en se déplaçant à une distance infinie dans l'espace des modules d'une théorie de la gravité quantique, une tour infinie d'états deviennent légers de façon exponentielle en la distance géodésique. Dans cette thèse, nous nous sommes concentrés sur certains aspects de cette conjecture dans des contextes spécifiques de la théorie des cordes. Tout d'abord, nous avons étudié comment ces états infiniment nombreux étendent les algèbres de symétrie dans les limites de décompactification des cordes hétérotiques et CHL sur des tores à d dimensions, qui correspondent à des théories de jauge de rang 16+d et 8+d, respectivement. Dans les deux cas, en utilisant la théorie sur la surface de la corde, nous avons montré qu'en allant à l'infini dans k ≤ d directions, les algèbres qui émergent sont la version affine de celles de la théorie de dimension supérieure 10-d+k vers laquelle nous décompactifions. De plus, nous montrons que la décompactification de la théorie CHL en théorie hétérotique, qui s'accompagne d'une augmentation du rang de la symétrie de jauge, est associée à la présence d'une version tordue de l'algèbre affine. Enfin, nous montrons que dans le cadre simple des espaces de modules symétriques (tels que ceux des compactifications toroïdales de la théorie M et de la théorie des cordes), il existe un lien naturel entre la géométrie de l'espace de modules et le spectre des cordes. Nous paramétrons la frontière de ces espaces de modules et caractérisons le comportement des géodésiques à l'infini, et en supposant un réseau d'états ainsi qu'en utilisant la complétude du spectre, nous prouvons la « Distance Conjecture » dans ces configurations
The string landscape is vast, and to many extents still unexplored. Nevertheless, in string compactifications it has been observed that common features appear, which are independent of the compactification itself, and that are believed to be deeply related to the quantum gravitational nature of the theory. Along these lines, the Swampland program aims to understand from a bottom-up perspective the conditions that an effective field theory should obey in order to be consistently UV completed to quantum gravity, for which string theory is, as of now, the most satisfactory framework. These constraints are currently expressed as a series of conjectures, which at a given energy divide the space of effective field theories into Landscape (namely, the ones that come from quantum gravity) and Swampland (the ones that despite being consistent as quantum field theories e.g. anomaly free, cannot be consistently coupled to quantum gravity). A typical feature of string compactifications is the presence of moduli, massless scalar fields with flat potential whose kinetic term in the supergravity action plays the role of a metric in a space parametrized by the moduli themselves, the so-called moduli space. Related to this, one of the most widely accepted conjectures, the Distance Conjecture, states that moving an infinite distance in the moduli space of a theory of quantum gravity, an infinite tower of states becomes exponentially light in the geodesic distance. In this thesis, we focused on some aspects of this conjecture in specific string theory settings. Firstly, we studied how these infinitely many states enhance the symmetry algebras in decompactification limits of Heterotic and CHL strings on d-dimensional tori, which correspond to gauge theories of rank 16+d and 8+d, respectively. In both cases, using the worldsheet theory we showed that taking k ≤ d radii to infinity, the algebras that emerge are the affine version of the ones in the higher 10-d+k dimensional theory we are decompactifying to. Moreover, we show that the decompactification of the CHL theory to the Heterotic one, which is accompanied by rank enhancement of the gauge symmetry, is associated with the presence of a twisted version of the affine algebra. Finally, we show that in the simple setting of symmetric moduli spaces (such as those of toroidal M- and string theory compactifications), there is a natural connection between the geometry of the moduli space and the string spectrum. We parametrize the boundary of these moduli spaces and characterize the behaviour of the geodesics at infinity, and assuming a lattice of states as well as using completeness of the spectrum we prove the Distance Conjecture in these setups

String theory offers the unique promise of unifying all the known forces in nature. However, the internal consistency of the theory requires that spacetime have more than four dimensions. As a result, the extra dimensions must be compactified in some manner and how this compactification takes place is critical for determining the low-energy physical predictions of the theory. In this thesis we examine two distinct consequences of this fact.First, almost all of the prior research in string model-building has examined the consequences of compactifying on so-called ``abelian'' orbifolds.However, the most general class of compactifications, namely those onnon-abelian orbifolds, remains almost completely unexplored. This thesis focuses on the low-energy phenomenological consequences of compactifying strings on non-abelian orbifolds. One of the main interests in pursuing these theories is that they can, in principle, naturally give rise tolow-energy models which simultaneously have N=1 super symmetry along with scalar particles transforming in the adjoint of the gauge group. These features,which are exceedingly difficult to achieve through abelian orbifolds,are exciting because they are the key ingredients in understanding how grand unification can emerge from string theory.Second, the need to compactify gives rise to a huge ``landscape'' of possible resulting low-energy phenomenologies. One of the goals of the landscape program in string theory is then to extract information about the space of string vacua in the form of statistical correlations between phenomenological features that are otherwise uncorrelated in field theory. Such correlations would thus represent features of string theory that hold independently of a vacuum-selection principle. In this thesis, we study statistical correlations between two features which are likely to be central to any potential description of nature at high-energy scales: gauge symmetries and spacetime supersymmetry. We analyze correlations between these two kinds of symmetry within the context of perturbative heterotic string vacua, and find a number of striking features. We find, for example, that the degree of spacetime supersymmetry is strongly correlated with the probabilities of realizing certain gauge groups, with unbroken supersymmetry at the string scale tending to favor gauge-group factors with larger rank. We also find that nearly half of the heterotic landscape is nonsupersymmetric and yet tachyon-free at tree level; indeed, less than a quarter of the tree-level heterotic landscape exhibits any supersymmetry at all at the string scale.

Prediction and control methodologies for ground deformation due to underground mining (commonly referred to as mine subsidence) provide engineers with the means to minimize negative effects on the surface. Due to the complexity of subsidence-related movements, numerous techniques exist for predicting mine subsidence behavior. This thesis focuses on the development, implementation, and validation of numerous enhanced subsidence prediction methodologies. To facilitate implementation and validation, the improved methodologies have been incorporated into the Surface Deformation Prediction System (SDPS), a computer program based primarily on the influence function method for subsidence prediction. The methodologies include dynamic subsidence prediction, alternative model calibration capability, and enhanced risk-based damage assessment. Also, the influence function method is further validated using measured case study data. In addition to discussion of previous research for each of the enhanced methodologies, a significant amount of background information on subsidence and subsidence-related topics is provided. The results of the research presented in this thesis are expected to benefit the mining industry, as well as initiate ideas for future research.
Master of Science

Under det senaste årtiondet har 97 % av den totala folkökningen tillkommit inom fem kilometer från kusten, främst kring storstadsregionerna. Tyresö kommun är en av Stockholms förorter. Kommunen har under åren köpt loss tomter i ett kustnära område vid Tyresö strand. Ekologigruppen ab har på uppdrag av kommunen gjort bedömningar av områdets naturvärden såväl som rekreativa värden. Bedömningarna är tänkta att kunna vila som beslutsunderlag för planering såväl som byggnationer i området. Utgångspunkter för uppsatsen är teorier, principer/begrepp och riktlinjer från främst bevarandeekologi, men även fysisk planering. Syftet med uppsatsen är att belysa konsekvenser som bebyggelse kan medföra på naturmiljön samt att utefter den förvärvade kännedomen ge rekommendationer för framtida byggnationer. Rekommendationerna fokuseras på områden som uppmärksammats som särskilt värdefulla/känsliga. De skyddsvärda naturmiljöer som identifierats är främst eklundarna och andra ädellövträd samt de grunda mjukbottnarna. Dessa miljöer kan skyddas och stärkas genom en god planering som bidrar till områdena begränsas intrång samt att man strävar efter att bevara en sammanhängande grönstruktur. De grunda bottnarna kan delvis skyddas genom en omlokalisering av planområdets befintliga båtklubb. Även de rekreativa värdena skulle stärkas genom båtklubbens flytt genom att vattenkontakten för allmänheten förbättras. Vattenkontakten och promenadmöjligheterna skulle även kunna stärkas av gångbryggor längs strandlinjen.

Over the past decade in Sweden, 97 % of total population growth has occurred within five kilometres of the coast, primarily round the urbanized regions. The municipality of Tyresö is a suburb of Stockholm and has, purchased land in a coastal region in Tyresö strand. Ekologigruppen ab was commissioned by the municipality to carry out an evaluation of the environmental and recreational values of the area. The evaluations are intended to form a basis for future planning and construction work. This essay is based on theories, principles/concepts/guidelines from the field of conservation-ecology and physical planning. The aim of the essay is to shed light on the consequenses that construction and development can entail for the environment and to make recommendations for future development on the basis on knowledge acquried. The recommendations will mainly focus on those areas which have been designated as being particularly valuable/sensitive. Such areas are primarily the oak-groves and other valuable deciduous trees as well as shallow water with soft bottom sea-beds. These environments can be protected and strengthened by appropriate planning which can help limit encroachment as well as promote efforts to preserve a coherent green-structure.The shallow sea-beds may be partly protected by relocating the areas boat club. Relocating the boat club would also enhance recreational values since it would provide the public with improved access to the water. Bridges along the shoreline would further enhance water-access and provide greater opportunities for walking.

Karl- Erik Nordström 2018. A strong and sacred Landscape. Central Places and Cosmology during the Iron Age   This study intends to address a specific aspect of the landscape, not only as something that can be linked to economic, political and legal factors but also spiritual and cosmological. Much of these thoughts have been taken from certain studies of "the strong landscape" that shape the beliefs and identities. Such ethnoarchaeological approach has grown to a great extent in recent decades and is represented internationally by several authors from the 70s and 80s, who in their Bronze Age studies highlight the importance of contemporary world of imagination.   Something that characterized much of the research tradition in the period after 1945 is building history and research around central places. The central site concept, which includes "a place of specific qualities", was not developed until the 1970s.   One thing that can not be avoided in this case is the adaptation to the harsh climate and the environmental problems that develop during the Iron Age, which in many cases have been devastating but can also involve reorganization, better use of resources and a more centralized structure. The emerging economic, political, legal and religious centers that the central places make up can be seen as an expression of this. Here, spiritual and cosmological performances about landscapes, towns, farms and houses have also been developed.   This aspect of the landscape as a cosmological unit I intend to study closer to the rich iron age community in Sundhede outside Hudiksvall. Here, a number of villages and smaller regions are grouped around a high-rise city center and here we also find outfields, which extract the substance that had an important significance during this time and also gave a spiritual cosmological significance, namely the iron. With this I hope to contribute to further knowledge of the role played by the landscape during the Iron Age, not least metaphysical.

L’esthétique du vide en photographie est aussi ancienne que le médium lui-même. Son origine remonte aux premiers balbutiements de la technique qui, visant à obtenir une représentation exacte de la nature, s’est retrouvé confrontée aux forces résistives du réel. À l’insu de tous, cette esthétique émergea d’une tension entre le geste de l’inventeur, du créateur, qui souhaite accomplir son projet – forcer la “nature” à son dessein – et le réel qui résiste et entrave les tentatives. Toute la photographie “primitive” est marquée plastiquement par ce tiraillement entre des forces antagonistes. L’illusion, tant souhaitée, d’une représentation fidèle se déroba, laissant à la postérité la beauté de ces images sans pareille, ouvrant l’espace aux possibles. Les zones obscures, troubles et vides ont participé activement à doter ces photographies d’une aura, plongeant les spectateurs dans des contemplations et des rêveries sans fin. La phénoménalité du monde a marqué de son sceau l’esthétique photographique, transformant paradoxalement les projets technicistes, épris de précision, en aventures plastiques singulières et étranges. Ce grand écart entre désir d’appréhension et résistance du réel a produit des effets, des traces tangibles de l’étrangeté même du monde. La maturité du médium et de ses acteurs aidant, il n’y a eu, ensuite, qu’un pas à franchir pour que coïncident ces traces et les questionnements philosophiques qui en résultent. Le vide, élément majeur de cette esthétique, fut repris à bon escient comme stratégie au service du sentiment du sublime. Pour mettre en scène ces problématiques, nous convoquons l’histoire du médium photographique et, avec elle, ses plus illustres acteurs. Cela nous servira de fil d’Ariane pour parcourir les deux siècles qui nous séparent de l’invention de la photographie et voir comment, au cours de l’histoire de ce médium, des photographes ont réactivé cette esthétique. Cette thèse se propose, à travers de riches analyses historiques, techniques et théoriques, d’évaluer les résonances de l’esthétique du vide en photographie, qui consiste à vider l’espace représentatif plutôt qu’à le remplir. Par des études de cas, pratique raisonnée de prises de vue à l’appui, nous tenterons aussi de démontrer comment la photographie est devenue, au fil du temps, un médium privilégié de contemplation, d’observation, d’examen critique des espaces laissés vacants au sein du tissu urbain et comment la dialectique entre lieux réels et représentations photographiques permet, en retour, une réflexion sur les enjeux paysagers de nos espaces urbains
The aesthetic of emptiness in photography is as old as the medium itself. Its origin goes back to the early days of the technique, which, aimed at obtaining an exact representation of nature, was confronted with the resistive forces of reality. Unbeknownst to all, this aesthetic emerged from a tension between the act of the inventor, the creator, who wishes to accomplish his project - to force "nature" to his design - and the real that resists and hinders attempts. All "primitive" photography is plastically marked by this tension between antagonistic forces. The illusion, so much desired, of a faithful representation fainted, leaving to posterity the beauty of these unique images, opening space to possibilities. The dark, troubled and empty areas actively participated in endowing these photographs with an aura, plunging viewers into contemplations and endless reveries. The phenomenality of the world has marked with his seal the photographic aesthetics, paradoxically transforming technicist projects, loving precision, in singular and strange plastic adventures. This great gap between the desire for apprehension and the resistance of reality has produced effects, tangible traces of strangeness of the world. The maturity of the medium and its actors helping, there was, then, only a step to cross to coincide these traces and philosophical questions that result. The emptiness, a major element of this aesthetic, was appropriately used as a strategy in the service of the feeling of the sublime.To stage these issues, we convene together the history of the photographic medium and most famous actors. This will serve as a clue to glance to the two centuries that separate us from the invention of photography and see how, in the history of the medium, photographers have reactivated this aesthetic. This thesis proposes, through rich historical, technical and theoretical analyzes, to evaluate the resonances of the vacuum aesthetic in photography, which consists in emptying the representative space rather than filling it. Through case studies, reasoned practice of shooting in support, we will also try to demonstrate how photography has become, over time, a privileged medium of contemplation, observation, critical examination of spaces left vacant within the urban fabric and how the dialectic between real places and photographic representations allows, in return, a reflection on the landscape issues of our urban spaces

The existing world is becoming more disrupted and is falling apart. For its resurrection and restoration, a new way of thinking is necessary. This new type of thinking is needed to be able to open up its mind and to think about the process of thinking itself; it must understand what is happening in other systems, where processes seem to be taking place by themselves without any other visible interference. First Chaos is the title for an intermedia installation which contains 90 black and white photographs, both digital and analogue, all of which were taken between the years 2008 and 2012. Together, the photographs create one coherent piece – a kind of sculpture. They can evoke a "still film" with a non-linear, cyclical storyline, whilst the images can simultaneously function individually, without any connection to other photographs.

This dissertation explores various facets of the low-energy solutions in string theory known as the string landscape. Three separate questions are addressed - the tunneling dynamics between these vacua, the statistics of their location in moduli space, and the potential realization of slow-roll inflation in the flux potentials generated in string theory. We find that the tunneling transitions that occur between a certain class of supersymmetric vacua related to each other via monodromies around the conifold point are sensitive to the details of warping in the near-conifold regime. We also study the impact of warping on the distribution of vacua near the conifold and determine that while previous work has concluded that the conifold point acts as an accumulation point for vacua, warping highly dilutes the distribution in precisely this regime. Finally we investigate a novel form of inflation dubbed spiral inflation to see if it can be realized near the conifold point. We conclude that for our particular models, spiral inflation seems to rely on a de Sitter-like vacuum energy. As a result, whenever spiral inflation is realized, the inflation is actually driven by a vacuum energy.

This thesis investigates the work of the twentieth-century Finnish modernist architect Alvar Aalto (1898-1976), as involved and intertwined with ideas and experiences of landscape. Late in his life, Aalto said that from his earliest years the Finnish landscape ‘was there all around me, all the time.’ Aalto has been regarded historically as the modernist misfit, a Northern humanist outlier working at the margins of rational modern architecture. Aalto’s architecture arguably extends, expands and evolves modernism to embrace a body-based humanism, informed by a socio-ethical agenda supporting the everyday ‘little man’, confronted by twentieth-century modernity. Aalto’s alternative or heterodox architecture is argued in this study as based in the historically acknowledged, yet largely unexplored, involvement of his work with landscape, evident in the conceptualisation, siting, design, details, and the experience of his work. This thesis investigates the significance of landscape in Aalto’s work by conceptualising his architecture in terms of its relationship to landscape, addressing the lack of a sustained study of the significance of landscape in Aalto’s work. This historical-theoretical study investigates Aalto’s architecture, in buildings, details and elements, drawings, unbuilt projects, and architectural images, from the 1920s to the 1970s. Through these selected historical examples, the involvement of landscape in Aalto’s work emerges as an essential difference, distinguishing his heterodox practice from the orthodoxy of twentieth-century modern architecture. The study innovatively organises Aalto’s work into three landscape-related historical themes, of White, Waves and Ruins. While landscape offered a topic for investigating landscape in Aalto’s work in this author’s MPhil(Arch) research into prospect-refuge symbolism (2010), these three themes emerged as relevant to investigating landscape through research articles published or presented by this author between 2010-2018. This study makes its particular contribution to architectural scholarship through a series of close readings of Aalto’s work, interpreting landscape in his architecture with reference to key phenomenological concepts of Place, Atmosphere and Embodiment. The study investigates renowned Aalto works such as Villa Mairea, Muuratsalo House and Aalto Atelier, along with lesser-known works such as Summa House, Alajärvi Town Hall and Seinäjoki Theatre, as well as sketches, images and details of Aalto works. The thesis describes, analyses and interprets the significance of both Aalto’s architecture in the landscape, and landscape elements in his architecture, with reference to Aalto’s ‘own words’, to the wider Aalto literature, and to interdisciplinary literature on the phenomenology of Place, Atmosphere and Embodiment. Aalto’s lifelong familiarity with the Finnish landscape and his experience of its topography, geology, vegetation, water, weather mythology gave him a unique capacity to involve his work with landscape. Aalto’s familiarity with landscape was further informed by his interests in biology, art, history and literature, and was driven in part by his empathy for the ‘little man’, the everyday person struggling with the conflicts and changes of the twentieth century. The analysis of the study refers to the thinking of Norberg-Schulz and Pallasmaa on architectural phenomenology. It builds also on Wylie’s geographical theorisation of the phenomenology of landscape, and is based indirectly on the phenomenological philosophies of Merleau-Ponty and of Heidegger, through architectural readings of their work. The study uses recent theoretical and historical work – including Malpas on place, Böhme on atmosphere, and Goldhagen on embodiment – to locate Aalto’s work within recent and contemporary thinking on phenomenology in landscape and architecture. Landscape is argued through the thesis as giving an ontological basis to Aalto’s method. Landscape emerges as forming a fundamental, originary architectural beginning, without which Aalto could not have imagined and created his architecture, without which experience of his work could not be fully described or investigated, and without which contemporary understanding of his work would remain less comprehensive. As such, landscape, categorised into historical themes of White, Waves and Ruins and read through phenomenological concepts of Place, Atmosphere and Embodiment, offers a unique resource for investigating the meaning and significance of Aalto’s architecture. As an investigation of landscape through its close reading of Aalto’s work, the present study aims to expand understanding of Aalto’s complex and enduring modern architecture, and of the broader significances of landscape for contemporary architectural thinking and practice.

Have you driven someplace, walked or climbed or jumped in from two miles up? Have you travelled thousands of kilometres world-wide by motor vehicle, round mazes of freeways and off the beaten track? Set against this activity are interruptions, intended or unintended; a necessary fuel stop, an unforeseen accident, R&R, times to debrief, reflect and record. On the road, this duality is a constant. It seemed that a focal point for exploring these opposing forces could be the SERVICE STATION - a place of brief stops and encounters, but also of continual movement -of machinery, vehicles, work; of coming, stopping and going. It was on this premise that this ballad opera was based.

Metagenomics, or genomic sequence of the community of microbiota (bacteria, fungi, virus), enables an investigation of the full complement of genetic material, including virulence, antibiotic resistance, and strain differentiating markers. The granularity to distinguish between closely related strains is important as within one species, these strains possess distinct functions and relationships to a host. To analyze metagenomic samples, I developed a reference-based approach that utilizes both single nucleotide variants and genetic content to assign species and strain-level designations. After refining this approach with complex simulated communities, I utilized it to analyze the microbial communities present in skin samples from healthy and diseased individuals. First, to investigate strain-level heterogeneity in healthy adults, I focused on the common skin commensals Propionibacterium acnes and Staphylococcus epidermidis with well-documented sequence variation. Results indicated that an individual’s strains of P. acnes are shared across multiple sites of his or her body, and that those strains are more similar within than between individuals. For S. epidermidis, in addition to individual site similarities, there were also site-specific strains. Overall these results emphasize that both individuality and site specificity shape our bodies’ microbial communities. Based on longitudinal data, an individual’s strain signatures remain stable for up to a year despite external, environmental perturbations. I then used metagenomic data to explore microbial temporal dynamics in atopic dermatitis (AD; eczema), an inflammatory skin disease commonly associated with Staphylococcal species. Species-level investigation of AD flares demonstrated a microbial dichotomy in which S. aureus predominated on more severely affected patients while S. epidermidis predominated on less severely affected patients. Strain-level analysis determined that S. aureus-predominant patients were monocolonized with distinct S. aureus strains, while all patients had heterogeneous S. epidermidis strain communities. To assess the host immunologic effects of these species, I topically applied patient-derived strains to mice. AD strains of S. aureus were sufficient to elicit a skin immune response, characteristic of AD patients. This suggests a model whereby staphylococcal strains contribute to AD progression through activation of the host immune system. Overall, this strain-level analysis of healthy and disease communities provides previously unexplored resolution of human skin microbiome.
2018-03-24T00:00:00Z

When a liquid is cooled below its equilibrium freezing temperature, it becomes supercooled and the molecular motions slow down until the system becomes kinetically arrested, forming a glass, at the glass transition temperature. These amorphous materials have the mechanical properties of a solid while retaining the structural properties of a liquid, but do not exhibit the usual features of a thermodynamic phase transition. As such, they present a number of important challenges to our understanding of the dynamics and thermodynamics of condensed phases. For example, supercooled liquids are classified on the basis of the temperature dependence of their transport properties and structural relaxations times. Strong liquids display an Arrhenius behavior, with the logarithm of their viscosity growing linearly with inverse temperature. Fragile liquids behave in a super-Arrhenius manner, where the viscosity appears to diverge at temperatures above absolute zero, suggesting the possibility of an underlying thermodynamic origin to the glass transition. Some complex, network forming liquids, such as water and silica have also been shown to have a dynamical crossover from fragile to strong liquid behavior as the temperature is decreased. The potential energy landscape paradigm, combined with inherent structure formalism, provide a framework for connecting the way particles pack together with the thermodynamics and dynamics of the liquid and glassy phases. However, the complexity of this multi-dimensional surface makes it difficult to fully characterize and rigorous relationships between the nature of particle packing and glass forming properties have not been established. The goal of this thesis is to study some of the general features of glass transition and find the connection between the dynamics and the thermodynamics of glass forming liquids. To this end, the packing landscapes of quasi-one-dimensional hard discs and hard spheres are studied. A two dimensional system of hard discs with diameter σ, confined between two hard walls (lines) of length L, separated by a distance 1