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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
791

CORRELAZIONI TRA SVILUPPO CONCETTUALE NELL'INFANZIA E ACQUISIZIONE DELLA PRIMA LINGUA / Relationships between conceptual development and first language acquisition

VERNICH, LUCA ANTONIO TOMMASO 23 March 2015 (has links)
L'obiettivo del presente lavoro è quello di esaminare criticamente le prospettive teoriche più note sul problema delle relazioni tra sviluppo concettuale del bambino ed acquisizione della prima lingua. Per quanto il lavoro si concentri in particolare sullo sviluppo della componente lessicale, ovvero sul legame tra concetti e apprendimento delle parole con cui gli stessi vengono codificati, verranno necessariamente trattati anche alcuni aspetti relativi alla competenza morfologica e sintattica. Dopo aver presentato sinteticamente le principali teorie proposte nell'ambito della linguistica acquisizionale e della psicologia dello sviluppo, procederemo ad una problematizzazione e discussione dei punti critici delle stesse alla luce dei risultati ottenuti in sede sperimentale negli ultimi anni. Partendo dalla consapevolezza che nell'ambito della linguistica, forse ancor più che in altre discipline, il contrasto tra impostazioni teoriche diverse si traduce spesso in discrepanze significative nell'interpretazione degli stessi dati empirici, abbiamo cercato di dare lo stesso spazio ai vari orientamenti teorici. L'obiettivo di questa tesi, infatti, non è quello di dare giudizi di merito sulla validità di una teoria in quanto tale rispetto ad un'altra, quanto di discutere in modo trasversale i nodi più problematici delle varie teorie e le implicazioni delle stesse. Questo intento è particolarmente evidente nelle conclusioni della tesi, strutturate intorno ad una serie di domande di ricerca. / This work provides a critical overview of the major theoretical perspectives on the relationships between conceptual development and first language acquisition. While our focus is on lexical development (ie. on the relation between learning a word and acquiring the relevant concept), we will also touch on some aspects which pertains more specifically to morphological and syntactical development. After briefly introducing the major theories developed in the field of first language acquisition and developmental psychology, we will discuss them in the light of experimental data collected in recent years. As the same empirical findings tend to be interpreted in completely different ways, in our work we tried to give voice to authors supporting different views. Our goal is not to assess the merits of these theores as such, but to take this comparison as an opportunity to discuss the implications and issues thereof. This will be particularly clear in the Conclusions of our work, which are structured as a series of research questions.
792

Gravitational Decoherence in Macroscopic Quantum Systems

Engelhardt Önne, Niklas January 2023 (has links)
The problem of how quantum mechanics gives rise to classicality has been debated for more than a century. A commonly proposed solution is decoherence, i.e. the gradual decay of superpositions in open quantum systems due to their inevitable interaction with their environment. However, the ability of decoherence to account for all aspects of the classical world is often questioned. A recently proposed model suggests that decoherence can occur even in isolated composite systems subject to gravitational time dilation, something which has sparked a debate. In this thesis we attempt to identify the precise role of decoherence in the quantum-to-classical transition (QTCT) and then use the result to analyze the validity of the newly proposed time dilation-induced decoherence mechanism. We find that the problem of the QTCT can be divided into two parts and that decoherence solves the first of these whereas the second is unsolvable without fundamental modifications to quantum theory. Moreover, we argue that the effect is fundamentally frame-dependent and we find a general formula for the rate of decoherence of macroscopic superpositions in the case where both the system and observer use Rindler coordinates. The result suggests that the frame-dependence may be utilized to increase the strength of the effect in experimental settings. Finally, the possibilities of experimental verification are discussed and we argue that recent advances in quantum measurement techniques in gravitational-wave observatories may enable tests of gravitational decoherence in the near future, finally providing an empirical glimpse into the resolution of one of the most critical debates in all of physics. / Huruvida kvantfysiken kan ge uppkomst till den klassiska fysiken på stora skalor är ett problem som diskuterats under mer än ett århundrade. En föreslagen lösning är dekoherens, alltså det gradvisa sönderfallet av superpositioner i öppna kvantsystem på grund av den oundvikliga interaktionen med deras omgivning. Dekoherensens förmåga att förklara alla delar av den klassiska världen ifrågasätts emellertid fortfarande. De senaste åren har en ny effekt uppmärksammats som tyder på att dekoherens även kan uppstå i isolerade kompositsystem under påverkan av gravitationell tidsdilatation, något som orsakat en debatt i litteraturen. I detta arbete försöker vi identifiera dekoherensens roll i övergången från det kvantmekaniska till det klassiska, och vi använder sedan resultatet för att analysera den ovannämnda gravitationella dekoherensmekanismen. Det allmänna problemet med övergången från kvantfysik till klassisk fysik delas upp i två delar, och vi visar att dekoherens löser den första delen; den andra delen visar sig vara olösbar utan fundamentala förändringar av kvantfysikens ramverk. Vidare visas den gravitationella dekoherenseffekten vara observatörsberoende och vi härleder en allmän formel för takten med vilken makroskopiska superpositioner sönderfaller i de fall då både systemet och observatören använder Rindlerkoordinater. Resultaten tyder på att observatörsberoendet eventuellt kan utnyttjas för att öka effektens styrka i experimentalla sammanhang. Slutligen diskuteras möjligheter att experimentellt verifiera effekten; vi argumenterar för att nya genombrott inom kvantmätteknik i gravitationsvågsobservatorium kan möjliggöra tester av gravitationell dekoherens inom en snar framtid, vilket skulle ge oss en första empirisk inblick i lösningen till en av fysikens mest kritiska debatter.
793

Entanglement Entropy in Cosmology and Emergent Gravity

Akhil Jaisingh Sheoran (15348844) 25 April 2023 (has links)
<p>Entanglement entropy (EE) is a quantum information theoretic measure that quantifies the correlations between a region and its surroundings. We study this quantity in the following two setups : </p> <ul> <li>We look at the dynamics of a free minimally coupled, massless scalar field in a deSitter expansion, where the expansion stops after some time (i.e. we quench the expansion) and transitions to flat spacetime. We study the evolution of entanglement entropy (EE) and the Rényi entropy of a spatial region during the expansion and, more interestingly, after the expansion stops, calculating its time evolution numerically. The EE increases during the expansion but the growth is much more rapid after the expansion ends, finally saturating at late times, with saturation values obeying a volume law. The final state of the subregion is a partially thermalized state, reminiscent of a Gibbs ensemble. We comment on application of our results to the question of when and how cosmological perturbations decohere.</li> <li>We study the EE in a theory that is holographically dual to a BTZ black hole geometry in the presence of a scalar field, using the Ryu-Takayangi (RT) formula. Gaberdiel and Gopakumar had conjectured that the theory of N free fermions in 1+1 dimensions, for large N, is dual to a higher spin gravity theory with two scalar fields in 2+1 dimensions. So, we choose our boundary theory to be the theory of N free Dirac fermions with a uniformly winding mass, m e<sup>iqx</sup>, in two spacetime dimensions (which describes for instance a superconducting current in an N-channel wire). However, to O(m<sup>2</sup>), thermodynamic quantities can be computed using Einstein gravity. We aim to check if the same holds true for entanglement entropy (EE). Doing calculations on both sides of the duality, we find that general relativity does indeed correctly account for EE of single intervals to O(m<sup>2</sup>).</li> </ul>
794

Mirrors And Vanities

Salas, Leslie 01 January 2013 (has links)
Mirrors and Vanities is a multi-modal collection which showcases the diversity of working in long and short storytelling forms. Featured in this thesis are fiction, nonfiction, graphic narrative, and screenplay. Using unconventional approaches to storytelling in order to achieve emotional resonance with the audience while maintaining high standards for craft, these stories and essays explore the costs inherent to the subtle nuances of interpersonal relationships. The fiction focuses on the complications of characters keeping secrets. A husband discovers the truth behind his wife’s miscarriage. A girl visits her fiancé in purgatory. A boy crosses a line and loses his best friend. Meanwhile, the nonfiction centers on self-discovery and gender roles associated with power struggles. A schizophrenic threatens to ruin my mother’s wedding. I rediscover my relationship with my father through food writing. Sword-work teaches me to fail and succeed at making martial art. The title work of the thesis is a collaged story highlighting the tribulations of a physicist fixated on recovering his lost love by manipulating the multiverse. The multi-modal format implicates the nebulosity of physics theories and how different aspects of the narrative can be presented in various formats to best suit the nature of the storytelling. Through the interactions of characters in mundane and extraordinary circumstances, the works in this thesis examine the consequences of choice, the contrast between reality and expectation, coming of age, and the Truth of narrative.
795

Renormalization of Gauge Theories and Gravity

Prinz, David Nicolas 22 November 2022 (has links)
Wir studieren die perturbative Quantisierung von Eichtheorien und Gravitation. Unsere Untersuchungen beginnen mit der Geometrie von Raumzeiten und Teilchenfeldern. Danach diskutieren wir die verschiedenen Lagrangedichten in der Kopplung der (effektiven) Quanten-Allgemeinen-Relativitätstheorie zum Standardmodell. Desweiteren studieren wir den zugehörigen BRST-Doppelkomplex von Diffeomorphismen und Eichtransformationen. Danach wenden wir Connes--Kreimer-Renormierungstheorie auf die perturbative Feynmangraph-Entwicklung an: In dieser Formulierung werden Subdivergenzen mittels des Koprodukts einer Hopfalgebra strukturiert und die Renormierungsoperation mittels einer algebraischen Birkhoff-Zerlegung beschrieben. Dafür verallgemeinern und verbessern wir bekannte Koprodukt-Identitäten und ein Theorem von van Suijlekom (2007), das (verallgemeinerte) Eichsymmetrien mit Hopfidealen verbindet. Insbesondere lässt sich unsere Verallgemeinerung auf Gravitation anwenden, wie von Kreimer (2008) vorgeschlagen. Darüberhinaus sind unsere Resultate anwendbar auf Theorien mit mehreren Vertexresuiden, Kopplungskonstanten und ebensolchen mit einer transversalen Struktur. Zusätzlich zeigen wir Kriterien für die Kompatibilität dieser Hopfideale mit Feynmanregeln und dem gewählten Renormierungsschema. Als nächsten Schritt berechnen wir die entsprechenden Gravitations-Materie Feynmanregeln für alle Vertexvalenzen und mit einem allgemeinen Eichparameter. Danach listen wir alle Propagator- und dreivalenten Vertex-Feynmanregeln auf und berechnen die entsprechenden Kürzungsidentitäten. Abschließend stellen wir geplante Folgeprojekte vor: Diese schließen eine Verallgemeinerung von Wigners Klassifikation von Elementarteilchen für linearisierte Gravitation ein, ebenso wie die Darstellung von Kürzungsidentitäten mittels Feynmangraph-Kohomologie und eine Untersuchung der Äquivalenz verschiedener Definitionen des Gravitonfeldes. Insbesondere argumentieren wir, dass das richtige Setup um perturbative BRST-Kohomologie zu studieren eine differentialgraduierte Hopfalgebra ist. / We study the perturbative quantization of gauge theories and gravity. Our investigations start with the geometry of spacetimes and particle fields. Then we discuss the various Lagrange densities of (effective) Quantum General Relativity coupled to the Standard Model. In addition, we study the corresponding BRST double complex of diffeomorphisms and gauge transformations. Next we apply Connes--Kreimer renormalization theory to the perturbative Feynman graph expansion: In this framework subdivergences are organized via the coproduct of a Hopf algebra and the renormalization operation is described as an algebraic Birkhoff decomposition. To this end, we generalize and improve known coproduct identities and a theorem of van Suijlekom (2007) that relates (generalized) gauge symmetries to Hopf ideals. In particular, our generalization applies to gravity, as was suggested by Kreimer (2008). In addition, our results are applicable to theories with multiple vertex residues, coupling constants and such with a transversal structure. Additionally, we also provide criteria for the compatibility of these Hopf ideals with Feynman rules and the chosen renormalization scheme. We proceed by calculating the corresponding gravity-matter Feynman rules for any valence and with a general gauge parameter. Then we display all propagator and three-valent vertex Feynman rules and calculate the respective cancellation identities. Finally, we propose planned follow-up projects: This includes a generalization of Wigner's classification of elementary particles to linearized gravity, the representation of cancellation identities via Feynman graph cohomology and an investigation on the equivalence of different definitions for the graviton field. In particular, we argue that the appropriate setup to study perturbative BRST cohomology is a differential-graded Hopf algebra.
796

我國保險代位理論與法制之再建構 / A Study on the Reconstruction of Insurance Subrogation in Taiwan

陳俊元, Chen, Chun-Yuan Unknown Date (has links)
保險代位之本質,可說是整個保險代位體系之核心所在。本文乃以保險代位之本質—亦即求償模式為重心,對於保險代位之相關問題,依序加以討論。本文首先自保險代位存在之法理、以及學說上對其之批評加以分析、並提出回應。在保險代位之求償模式方面,我國傳統以來循大陸法系之傳統,採取法定債權移轉理論,而與英美法有所不同;英美法之架構近年來漸受學說之重視,甚至對其有所爭議,故實有釐清之必要。本文乃對英美保險代位之本質、架構加以探索,並對其與擬制信託之融合詳加分析,以求釐清其法律關係。除了英美以外,本文亦對其他主要國家之立法例詳加分析,並歸納為大陸法系與英美法系兩大系統。而中國大陸與台灣均屬於繼受法之地位,關於保險代位求償模式、名義等,亦可見受不同立法例所影響之軌跡;其許多條款與學說見解亦有疑義,值得我國引以為戒。於分析英美法與各國立法例,並審酌我國之背景後,本文乃嘗試對我國提出「保險代位求償模式相對論」—即原則上仍採取法定債權移轉理論,但在保險人與被保險人有特定具體之特約時,則可約定採取英美法之模式、或是自行約定其他求償模式。 另外,關於不足額保險、而應負責之第三人資力不足時,保險人與被保險人之間受償順序之問題,本文將由傳統的法釋義學方法出發,藉由對立法例、實務與學說見解的分析,以重新思考相關的法理基礎。本文也將使用法律經濟分析的方法,以經濟模型重新考量代位求償過程中可能的因素,重新驗證被保險人優先受償模式對於被保險人的效用。就結論而言,在損失填補原則的架構下,被保險人優先受償模式仍應為最適的解決方案。但此原則應有以法規或嚴格意定予以排除、修正之空間。在判斷順序上,可依三階段判斷:先檢視法規有無特別規定,再檢視當事人間是否有特別約定,若均無再適用被保險人優先受償模式以分配之。 對於特別保險—如全民健康保險法、勞工保險條例、強制汽車責任保險法等中之代位體系,本文亦加以分析,並同樣認為於適當之類型中,本文之保險代位模式求償相對論亦應可加以適用。在再保險與保險代位之適用問題上,本文肯認保險人對第三人之求償無庸扣除再保險之給付。而對於再保險是否、如何適用於保險代位,本文則認為可以三階段判斷之:首先,就再保險之類型為判斷;再判斷原保險人是否欲向第三人求償;如再保險之類型適合、又原保險人不欲向第三人求償時,則應允許再保險人向第三求償。最後,總結全文提出結論;並分三階段對於我國法提出相關建議,以供未來進一步之參酌。 / The nature of subrogation can be regarded as the core of the subrogation system. This research put stress on the nature of subrogation which was the subrogation. Regarding the related problems of subrogation, they will be discussed orderly. The article firstly starts to analyze from the existence of subrogation and the criticism for the theory to provide the responses. In the aspect of the way how subrogation operates, our country traditionally follows the Continental Law System to adopt the “legal assignment theory” which is different the Anglo-American Law System. The structure of Anglo-American Law System is stressed by the theory and is very controversial. Consequently, it is necessary to figure out the truth. This research is aimed at exploring the nature and structure of common law subrogation theory and analyzes other integration of the constructive trust to figure out the law relationship. Except for Anglo-American countries, this research also analyzes the lawmaking of other countries and induces the two main systems which are Continental Law System and Anglo-American Law System. Mainland China and Taiwan belong to the status of Succession Law. Regarding the subrogation and nominal, it can be seen that the orbit is affected by different ways of lawmaking. Understandings of many clauses and theories are still uncertain. Our country should learn a lesson from it. With analyzing the ways of lawmaking of common law and each country, and considering the background of our country, the research attempts to address the “relativity theory of insurance subrogation” to our country. In principle, it still adopts legal assignment theory. However, when the insurer and insured have specific agreement, they can negotiate to adopt the Anglo-American model or make other subrogation model by themselves. Other problems can arise with regard to payment priority between the insurer and the insured, particularly in cases of underinsurance and when the responsible third party has insufficient funds to make up the difference. The present study takes the traditional rechtsdogmatik approach as its starting point, analyzing legislative precedents, practical aspects and academic theories to re-examine the underlying legal principles. The paper also makes use of economic analysis of law techniques, employing economic models to reconsider the factors that may be involved in the subrogation process, and re-examining the efficacy of the insured-whole doctrine from the point of view of the insured. The main conclusions reached are that, within the framework created by the principle of indemnity, the insured-whole doctrine is still the optimal solution; however, there may be situations in which the insured-whole doctrine must be rejected or modified in light of legal or regulatory requirements or strict interpretation. Determination can be made in three stages. Firstly, the relevant laws and regulations should be examined to determine whether any special provisions apply. Then, an examination should be made to determine whether any special agreements exist between the parties concerned. If no special legal or regulatory provisions apply and no special agreements exist, then the insured-whole doctrine can be applied. For the subrogation systems in special insurances—for examples, the National Health Insurance, Labor Insurance, and Compulsory Automobile Liability Insurance, the research also analyzes them and considers that in the proper type, the relativity theory of insurance subrogation can be adopted. About the problems about reinsurance and subrogation, this research admits that insurer asks for subrogation for the third party not need to deduct from settlement of reinsurance. For reinsurer and how to apply to the subrogation, the research considers that it can be judged from three stages. If the type of reinsurance is suitable and the original insurer does not want to claim against the third party, it should be allowed that the reinsurer can claim against the third party directly. Finally, the research makes the conclusion and provides related suggestions to the law of our country to be viewed as the future reference.
797

Computational Bayesian techniques applied to cosmology

Hee, Sonke January 2018 (has links)
This thesis presents work around 3 themes: dark energy, gravitational waves and Bayesian inference. Both dark energy and gravitational wave physics are not yet well constrained. They present interesting challenges for Bayesian inference, which attempts to quantify our knowledge of the universe given our astrophysical data. A dark energy equation of state reconstruction analysis finds that the data favours the vacuum dark energy equation of state $w {=} -1$ model. Deviations from vacuum dark energy are shown to favour the super-negative ‘phantom’ dark energy regime of $w {< } -1$, but at low statistical significance. The constraining power of various datasets is quantified, finding that data constraints peak around redshift $z = 0.2$ due to baryonic acoustic oscillation and supernovae data constraints, whilst cosmic microwave background radiation and Lyman-$\alpha$ forest constraints are less significant. Specific models with a conformal time symmetry in the Friedmann equation and with an additional dark energy component are tested and shown to be competitive to the vacuum dark energy model by Bayesian model selection analysis: that they are not ruled out is believed to be largely due to poor data quality for deciding between existing models. Recent detections of gravitational waves by the LIGO collaboration enable the first gravitational wave tests of general relativity. An existing test in the literature is used and sped up significantly by a novel method developed in this thesis. The test computes posterior odds ratios, and the new method is shown to compute these accurately and efficiently. Compared to computing evidences, the method presented provides an approximate 100 times reduction in the number of likelihood calculations required to compute evidences at a given accuracy. Further testing may identify a significant advance in Bayesian model selection using nested sampling, as the method is completely general and straightforward to implement. We note that efficiency gains are not guaranteed and may be problem specific: further research is needed.
798

Twentieth-century poetry and science : science in the poetry of Hugh MacDiarmid, Judith Wright, Edwin Morgan, and Miroslav Holub

Gibson, Donald January 2015 (has links)
The aim of this thesis is to arrive at a characterisation of twentieth century poetry and science by means of a detailed study of the work of four poets who engaged extensively with science and whose writing lives spanned the greater part of the period. The study of science in the work of the four chosen poets, Hugh MacDiarmid (1892 – 1978), Judith Wright (1915 – 2000), Edwin Morgan (1920 – 2010), and Miroslav Holub (1923 – 1998), is preceded by a literature survey and an initial theoretical chapter. This initial part of the thesis outlines the interdisciplinary history of the academic subject of poetry and science, addressing, amongst other things, the challenges presented by the episodes known as the ‘two cultures' and the ‘science wars'. Seeking to offer a perspective on poetry and science more aligned to scientific materialism than is typical in the interdiscipline, a systemic challenge to Thomas Kuhn's The Structure of Scientific Revolutions (1962) is put forward in the first chapter. Additionally, the founding work of poetry and science, I. A. Richards's Science and Poetry (1926), is assessed both in the context in which it was written, and from a contemporary viewpoint; and, as one way to understand science in poetry, a theory of the creative misreading of science is developed, loosely based on Harold Bloom's The Anxiety of Influence (1973). The detailed study of science in poetry commences in Chapter II with Hugh MacDiarmid's late work in English, dating from his period on the Shetland Island of Whalsay (1933 – 1941). The thesis in this chapter is that this work can be seen as a radical integration of poetry and science; this concept is considered in a variety of ways including through a computational model, originally suggested by Robert Crawford. The Australian poet Judith Wright, the subject of Chapter III, is less well known to poetry and science, but a detailed engagement with physics can be identified, including her use of four-dimensional imagery, which has considerable support from background evidence. Biology in her poetry is also studied in the light of recent work by John Holmes. In Chapter IV, science in the poetry of Edwin Morgan is discussed in terms of its origin and development, from the perspective of the mythologised science in his science fiction poetry, and from the ‘hard' technological perspective of his computer poems. Morgan's work is cast in relief by readings which are against the grain of some but not all of his published comments. The thesis rounds on its theme of materialism with the fifth and final chapter which studies the work of Miroslav Holub, a poet and practising scientist in communist-era Prague. Holub's work, it is argued, represents a rare and important literary expression of scientific materialism. The focus on materialism in the thesis is not mechanistic, nor exclusive of the domain of the imagination; instead it frames the contrast between the original science and the transformed poetic version. The thesis is drawn together in a short conclusion.

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