956 resultados para Modern portfolio theory
Resumo:
High temperature superconductivity in the cuprates remains one of the most widely investigated, constantly surprising and poorly understood phenomena in physics. Here, we describe briefly a new phenomenological theory inspired by the celebrated description of superconductivity due to Ginzburg and Landau and believed to describe its essence. This posits a free energy functional for the superconductor in terms of a complex order parameter characterizing it. We propose that there is, for superconducting cuprates, a similar functional of the complex, in plane, nearest neighbor spin singlet bond (or Cooper) pair amplitude psi(ij). Further, we suggest that a crucial part of it is a (short range) positive interaction between nearest neighbor bond pairs, of strength J'. Such an interaction leads to nonzero long wavelength phase stiffness or superconductive long range order, with the observed d-wave symmetry, below a temperature T-c similar to zJ' where z is the number of nearest neighbors; d-wave superconductivity is thus an emergent, collective consequence. Using the functional, we calculate a large range of properties, e. g., the pseudogap transition temperature T* as a function of hole doping x, the transition curve T-c(x), the superfluid stiffness rho(s)(x, T), the specific heat (without and with a magnetic field) due to the fluctuating pair degrees of freedom and the zero temperature vortex structure. We find remarkable agreement with experiment. We also calculate the self-energy of electrons hopping on the square cuprate lattice and coupled to electrons of nearly opposite momenta via inevitable long wavelength Cooper pair fluctuations formed of these electrons. The ensuing results for electron spectral density are successfully compared with recent experimental results for angle resolved photo emission spectroscopy (ARPES), and comprehensively explain strange features such as temperature dependent Fermi arcs above T-c and the ``bending'' of the superconducting gap below T-c.
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Be the strong coupling constant alpha(s) from the tau hadronn width using a renormalization group summed (RGS) expansion of the QCD Adler lunction. The main theoretical uncertainty in the extraction of as is due to the manner in which renormalization group invariance is implemented, and the as yet uncalculated higher order terms in the QCD perturbative series. We show that new expansion exhibits good renormalization group improvement and the behavior of the series is similar to that of the standard RGS expansion. The value of the strong coupling in (MS) over bar scheme obtained with the RCS expansion is alpha(s) (M-tau(2)) = 0.338 +/- 0.010. The convergence properties of the new expansion can be improved by Bond transformation and analytic continuation in t he Bond plane. This is discussed elsewhere in these issues.
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Investigando a apresentação das ideias em Sobre versos de Virgílio, a tese demonstra como sua estruturação ambígua, onde tudo é constantemente negado por seus contrários, leva a um contínuo estado de confusão e perplexidade, tornando impossível a determinação lógica dos conceitos e conduzindo a um progressivo esvaziamento do texto enquanto signo direto do pensamento do autor. Por outro lado, partindo de uma perspectiva hermenêutica influenciada pela anatomia, a análise mostra que o uso sistemático e criativo das instâncias narrativas (autor, narrador, signatário), juntamente com a reunificação textual de diferentes Montaignes (presentes nos diversos estágio editoriais do ensaio), acaba por dissolver a própria noção de identidade a si do autor, tendo por consequência imediata sua disseminação em vários sujeitos diversos e contraditórios e, por fim, colocando em xeque a clássica percepção dos Ensaios com o nascimento da subjetividade moderna.
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Hartle's model provides the most widely used analytic framework to describe isolated compact bodies rotating slowly in equilibrium up to second order in perturbations in the context of General Relativity. Apart from some explicit assumptions, there are some implicit, like the "continuity" of the functions in the perturbed metric across the surface of the body. In this work we sketch the basics for the analysis of the second order problem using the modern theory of perturbed matchings. In particular, the result we present is that when the energy density of the fluid in the static configuration does not vanish at the boundary, one of the functions of the second order perturbation in the setting of the original work by Hartle is not continuous. This discrepancy affects the calculation of the change in mass of the rotating star with respect to the static configuration needed to keep the central energy density unchanged.
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As one facet of an effort to tie the pollen record of central Gulf of California deep cores to modern analogs, pollen was analyzed in the uppermost 150-200 years of varved core 7807-1410 taken nearby. Sampling at 2- to 8-year resolution yielded a noncomplacent record, suggesting pollen in these sediments may be a potential high resolution proxy record of short-term climatic events. The pollen spectrum as a whole matches that of upper-most DSDP Site 480 (means of all samples). Lack of a ratio or influx shift following damming of local rivers and a surplus of low-spine Compositae pollen relative to mainland sites support Baumgartner's theory that terrigenous influx to the site is largely aeolian and also suggest that a significant fraction of the pollen influx may come from Baja California.
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Fun and exciting textbook on the mathematics underpinning the most dynamic areas of modern science and engineering.
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In order to resist lateral loads, modern methods of timber construction are reliant on the in-plane shear strength of the walls orientated parallel to the applied action. In closed panel systems, the shear stresses are transferred to the foundations by the sole plate through the sheathing board, which is usually mechanically jointed to the timber frame. Since closed panels are delivered to site as single units, access to the internal bottom rail is rather restricted and novel, efficient solutions to secure the panel to the substrate are required. Sole plate fixing components for open and closed panel systems were tested in isolation and combination in order to validate a simplistic version of the weakest link theory. As a result, findings were embedded into a software database with a direct link to a previously developed sole plate and racking design application. This integrated process facilitates the structural optimization of the sole plate detail.
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My text is an attempt to apply Charles Taylor’s theory, dealing with the origins of the modern self, to Czech autobiographical literature originating in Romanticism. Taking a cue from Jean Starobinski and Philippe Lejeune’s concepts of modern autobiography, I analyse Karel Hynek Mácha’s personal diary from 1835 and try to find and emphasize its narrative and compositional aspects, which anticipate the poetics of modern poetic diaries.
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This Thesis is an exploration of potential enhancement in effectiveness, personally, professionally and organisationally through the use of Theory as an Apparatus of Thought. Enhanced effectiveness was sought by the practitioner (Subject), while in transition to becoming Chief Executive of his organization. The introduction outlines the content and the structure of the University College Cork DBA. Essay One outlines what Theory is, what Adult Mental Development is and an exploration of Theories held in the Authors past professional practice. Immunity to change is also reflected on. Essay Two looks at the construct of the key Theories used in the Thesis. Prof. Robert Kegan’s Theory of Adult Mental Development was used to aid the generation of insight. The other key Theories used were The Theory of The Business, Theory of the Co‐operative and a Theory of Organisational Leadership. Essay Three explores the application of the key Theories in a professional setting. The findings of the Thesis were that the subject was capable of dealing with increased environmental complexity and uncertainty by using Theory as an Apparatus of Thought, which in turn enhanced personal, professional and organisational effectiveness. This was achieved by becoming more aware of the Theories held by the practitioner, the experiences from the application of those Theories, which then led to greater insight. The author also found that a detailed understanding of the Theory of the Business and a Theory of Leadership would support any new CEO in the challenging early part of their tenure.
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In an attempt to provide an analytical entry point into my compositional practice, I have identified eight themes which are significantly recurrent: reduction – the selection of a small number of elements; imperfection – a damaged or warped characteristic of sound; hierarchy – a concern with the roles of instruments with regard to their relative prominence; motion – apparently static sound masses consist of fine internal movement; listener perception – expectations for change influence the experience of affect; translation – the transitioning of electronic sounds to the acoustic realm, and vice versa; immersion – the creation of an accommodating soundscape; blurring – smearing and overlapping sounds or genres. Each of these eight factors is associated with relevant precedents in the history and theory of music that have been influential on my work. These include the minimalist compositions of Steve Reich and Arvo Pärt; the lo-fi aesthetic of Boards of Canada and My Bloody Valentine; concerns with political hierarchy in the work of Louis Andriessen; the variations of dynamics and microtonal shifts of Giacinto Scelsi; Leonard B. Meyer's account of expectation in music; cross-fertilisation of the acoustic and electronic in pieces by Gérard Grisey and Gyorgy Ligeti; the immersive technique of Brian Eno's ambient music; and the overlapping sounds of Aphex Twin. These eight factors are variously applicable to the eleven submitted pieces, which are individually analysed with reference to the most significant of the categories. Together they form a musical language that sustains the interaction of a variety of techniques, concepts and genres.
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For centuries Cork’s Shawlies, working-class women, survived by trading on public streets. My study explores how the first Irish Free State government, and Cork’s local authority, limited the rights of poor women to earn by subsistence trading with The Street Trading Act, 1926. The government insisted this would regulate street trading. In practice it further marginalised the women economically and socially, containing them outside the privileged, commercial city centre. In Cork the legislation facilitated the gradual disappearance of the Shawlies amid entrenched social processes and relations, contingencies that allowed for the abuse of their rights in the service of amalgamated business interests. This study address the role of discourses in deepening this marginalisation. My theoretical framework is designed to demonstrate how a seemingly innocuous piece of legislation would, in practice, do this. I set out the concepts of ‘Thriving State’, ‘Prosperous State’, and state of ‘Best Intentions’ that uses gentrification to meet these goals. The existing knowledge on women in trade is then examined, highlighting the gaps in what is known about the Shawlies. Chapter 3 details the theory behind my genealogical method. The legislation, debate, and other data produced at the national level is then examined, before moving to the local data. Chapter 6 is devoted to the Shawlies, setting their stories in the larger context of the debates. An examination of studies of contemporary women street traders in poor nations follows, along with a brief history of the decline of street trading in New York city under gentrification. Points of convergence between that process and the one in Cork are identified, along with convergences between contemporary traders and the Shawlies. The conclusion sets out my methodological, theoretical and substantive discoveries, and comments on current nostalgic renderings of the Shawlies in Cork’s newly gentrified Corn Market Street.
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A growing number of software development projects successfully exhibit a mix of agile and traditional software development methodologies. Many of these mixed methodologies are organization specific and tailored to a specific project. Our objective in this research-in-progress paper is to develop an artifact that can guide the development of such a mixed methodology. Using control theory, we design a process model that provides theoretical guidance to build a portfolio of controls that can support the development of a mixed methodology for software development. Controls, embedded in methods, provide a generalizable and adaptable framework for project managers to develop their mixed methodology specific to the demands of the project. A research methodology is proposed to test the model. Finally, future directions and contributions are discussed.
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Hannah Arendt's theory of political judgment has been an ongoing perplexity among scholars who have written on her. As a result, her theory of judgment is often treated as a suggestive but unfinished aspect of her thought. Drawing on a wider array of sources than is commonly utilized, I argue that her theory of political judgment was in fact the heart of her work. Arendt's project, in other words, centered around reestablishing the possibility of political judgment in a modern world that historically has progressively undermined it. In the dissertation, I systematically develop an account of Arendt's fundamentally political and non-sovereign notion of judgment. We discover that individual judgment is not arbitrary, and that even in the complex circumstances of the modern world there are valid structures of judgment which can be developed and dependably relied upon. The result of this work articulates a theory of practical reason which is highly compelling: it provides orientation for human agency which does not rob it of its free and spontaneous character; shows how we can improve and cultivate our political judgment; and points the way toward the profoundly intersubjective form of political philosophy Arendt ultimately hoped to develop.
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Modern forms of speculative philosophy continue to creep ‘unsuspectingly’ into our understanding of contemporary media/electronic arts, despite (or perhaps even because of) the attempts by Latour, Badiou, or Agamben especially when addressing the zero/one as if a contradictory ‘binary’ rather than as a kind of 'slice’ or (to use Deleuze and Guattari) an immanent plane of immanence. We argue that by playing with and against Neitzsche, Einstein, Godel, and Deleuze, a rather different story of art, not to mention philosophy, can be told. [From conference programme]