869 resultados para Limit of meaning of a Scientific Theory


Relevância:

100.00% 100.00%

Publicador:

Resumo:

Discusses the termination of desegregation decrees and the elusive meaning of unitary status, first introducing the topic and then covering Jenkins III and providing an overview of desegregation scholarship including discretion, capacity, and legitima. Also discusses the evolution of equity, including English equity, American equity, and equity and desegregation. Explores the concepts of relevant rights and interests, focusing on Hohfeld, the interest theory of rights, and the application of the rights theory. The conclusion posits that what remains is a complicated and confused desegregation jurisprudence, and that the lines that separate desegregation from integration from diversity, if there ever were such lines, are blurring. A discussion of the theoretical premises underlying desegregation appears to continue to be necessary.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Quarks were introduced 50 years ago opening the road towards our understanding of the elementary constituents of matter and their fundamental interactions. Since then, a spectacular progress has been made with important discoveries that led to the establishment of the Standard Theory that describes accurately the basic constituents of the observable matter, namely quarks and leptons, interacting with the exchange of three fundamental forces, the weak, electromagnetic and strong force. Particle physics is now entering a new era driven by the quest of understanding of the composition of our Universe such as the unobservable (dark) matter, the hierarchy of masses and forces, the unification of all fundamental interactions with gravity in a consistent quantum framework, and several other important questions. A candidate theory providing answers to many of these questions is string theory that replaces the notion of point particles by extended objects, such as closed and open strings. In this short note, I will give a brief overview of string unification, describe in particular how quarks and leptons can emerge and discuss what are possible predictions for particle physics and cosmology that could test these ideas.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Quarks were introduced 50 years ago opening the road towards our understanding of the elementary constituents of matter and their fundamental interactions. Since then, a spectacular progress has been made with important discoveries that led to the establishment of the Standard Theory that describes accurately the basic constituents of the observable matter, namely quarks and leptons, interacting with the exchange of three fundamental forces, the weak, electromagnetic and strong force. Particle physics is now entering a new era driven by the quest of understanding of the composition of our Universe such as the unobservable (dark) matter, the hierarchy of masses and forces, the unification of all fundamental interactions with gravity in a consistent quantum framework, and several other important questions. A candidate theory providing answers to many of these questions is string theory that replaces the notion of point particles by extended objects, such as closed and open strings. In this short note, I will give a brief overview of string unification, describe in particular how quarks and leptons can emerge and discuss what are possible predictions for particle physics and cosmology that could test these ideas.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

We regularize compact and non-compact Abelian Chern–Simons–Maxwell theories on a spatial lattice using the Hamiltonian formulation. We consider a doubled theory with gauge fields living on a lattice and its dual lattice. The Hilbert space of the theory is a product of local Hilbert spaces, each associated with a link and the corresponding dual link. The two electric field operators associated with the link-pair do not commute. In the non-compact case with gauge group R, each local Hilbert space is analogous to the one of a charged “particle” moving in the link-pair group space R2 in a constant “magnetic” background field. In the compact case, the link-pair group space is a torus U(1)2 threaded by k units of quantized “magnetic” flux, with k being the level of the Chern–Simons theory. The holonomies of the torus U(1)2 give rise to two self-adjoint extension parameters, which form two non-dynamical background lattice gauge fields that explicitly break the manifest gauge symmetry from U(1) to Z(k). The local Hilbert space of a link-pair then decomposes into representations of a magnetic translation group. In the pure Chern–Simons limit of a large “photon” mass, this results in a Z(k)-symmetric variant of Kitaev’s toric code, self-adjointly extended by the two non-dynamical background lattice gauge fields. Electric charges on the original lattice and on the dual lattice obey mutually anyonic statistics with the statistics angle . Non-Abelian U(k) Berry gauge fields that arise from the self-adjoint extension parameters may be interesting in the context of quantum information processing.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

The 15th International Geological Congress was held in South Africa in 1929. Many interesting issues were tackled, thanks to the development of geophysical techniques, ideas about magmatic differentiation, and the origin of the Karroo System, among others. The importance of the Congress from the point of view of the history of geology lies in the fact that an ‘inflection point’ occurred as regards thinking about the continental drift theory that had been proposed by Wegener a few years earlier. It can be said that the contributions of Du Toit allowed a deepening in the theoretical bases of this scientific hypothesis, which celebrated its first hundred years in 2012.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

A theory is developed of an electrostatic probe in a fully-ionized plasma in the presence of a strong magnetic field. The ratio of electron Larmor radius to probe transverse dimension is assumed to be small. Poisson's equation, together with kinetic equations for ions and electrons are considered. An asymptotic perturbation method of multiple scales is used by considering the characteristic lengths appearing in the problem. The leading behavior of the solution is found. The results obtained appear to apply to weaker fields also, agreeing with the solutions known in the limit of no magnetic field. The range of potentials for wich results are presented is limited. The basic effects produced by the field are a depletion of the plasma near the probe and a non-monotonic potential surrounding the probe. The ion saturation current is not changed but changes appear in both the floating potential Vf and the slope of the current-voltage diagram at Vf. The transition region extends beyond the space potential Vs,at wich point the current is largely reduced. The diagram does not have an exponential form in this region as commonly assumed. There exists saturation in electron collection. The extent to which the plasma is disturbed is determined. A cylindrical probe has no solution because of a logarithmic singularity at infinity. Extensions of the theory are considered.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Thesis (Ph.D.)--University of Washington, 2016-06

Relevância:

100.00% 100.00%

Publicador:

Resumo:

In the absence of an external frame of reference-i.e., in background independent theories such as general relativity-physical degrees of freedom must describe relations between systems. Using a simple model, we investigate how such a relational quantum theory naturally arises by promoting reference systems to the status of dynamical entities. Our goal is twofold. First, we demonstrate using elementary quantum theory how any quantum mechanical experiment admits a purely relational description at a fundamental. Second, we describe how the original non-relational theory approximately emerges from the fully relational theory when reference systems become semi-classical. Our technique is motivated by a Bayesian approach to quantum mechanics, and relies on the noiseless subsystem method of quantum information science used to protect quantum states against undesired noise. The relational theory naturally predicts a fundamental decoherence mechanism, so an arrow of time emerges from a time-symmetric theory. Moreover, our model circumvents the problem of the collapse of the wave packet as the probability interpretation is only ever applied to diagonal density operators. Finally, the physical states of the relational theory can be described in terms of spin networks introduced by Penrose as a combinatorial description of geometry, and widely studied in the loop formulation of quantum gravity. Thus, our simple bottom-up approach (starting from the semiclassical limit to derive the fully relational quantum theory) may offer interesting insights on the low energy limit of quantum gravity.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

The first motivation for this note is to obtain a general version of the following result: let E be a Banach space and f : E → R be a differentiable function, bounded below and satisfying the Palais-Smale condition; then, f is coercive, i.e., f(x) goes to infinity as ||x|| goes to infinity. In recent years, many variants and extensions of this result appeared, see [3], [5], [6], [9], [14], [18], [19] and the references therein. A general result of this type was given in [3, Theorem 5.1] for a lower semicontinuous function defined on a Banach space, through an approach based on an abstract notion of subdifferential operator, and taking into account the “smoothness” of the Banach space. Here, we give (Theorem 1) an extension in a metric setting, based on the notion of slope from [11] and coercivity is considered in a generalized sense, inspired by [9]; our result allows to recover, for example, the coercivity result of [19], where a weakened version of the Palais-Smale condition is used. Our main tool (Proposition 1) is a consequence of Ekeland’s variational principle extending [12, Corollary 3.4], and deals with a function f which is, in some sense, the “uniform” Γ-limit of a sequence of functions.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Major infrastructure assets are often governed by a mix of public and private organizations, each fulfilling a specific and separate role i.e. policy, ownership, operation or maintenance. This mix of entities is a legacy of Public Choice Theory influenced NPM reforms of the late 20th century. The privatization of the public sector has resulted in agency theory based ‘self-interest’ relationships and governance arrangements for major infrastructure assets which emphasize economic efficiency but which do not do not advance non-economic public values and the collective Public Interest. The community is now requiring that governments fulfill their stewardship role of also satisfying non-economic public values such as sustainability and intergenerational responsibility. In the 21st century governance arrangements which minimize individual self-interest alone and look to also pursue the interests of other stakeholders have emerged. Relational contracts, Public-Private Partnerships (PPP’s) and hybrid mixes of organizations from the state, market and network modes (Keast et al 2006) provide options for governance which better meet the interests of contractors, government and the community there is emerging a body of research which extends the consideration of the immediate governance configuration to the metagovernance environment constituted by hierarchy, regulation, industry standards, trust, culture and values. Stewardship theory has reemerged as a valuable aid in the understanding of the features of governance configurations which establish relationships between principal and agent which maximize the agent acting in the interests of the principal, even to the detriment of the agent. This body of literature suggests that an improved stewardship outcome from infrastructure governance configurations can be achieved by the application of the emerging options as to the immediate governance configuration, and the surrounding metagovernance environment. Stewardship theory provides a framework for the design of the relationships within that total governance environment, focusing on the achievement of a better, complete stewardship outcome. This paper explores the directions future research might take in seeking to improve the understanding of the design of the governance of major, critical infrastructure assets.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

This article attempts to explore the concept of scientific community at the macro-national level in the context of Iran. Institutionalisation of science and its professional growth has been constrained by several factors. The article first conceptualises the notion of science community as found in the literature in the context of Iran, and attempts to map through some indicators. The main focus, however, lies in mapping some institutional problems through empirical research. This was undertaken in 2002–04 in order to analyse the structure of the scientific community in Iran in the ‘exact sciences’ (mathematics, physics, chemistry, biology and earth sciences). The empirical work was done in two complementary perspectives: through a questionnaire and statistical analysis of it, and through semistructured interviews with the researchers. There are number of problems confronting scientists in Iran. Facilities provided by institutions is one of the major problems of research. Another is the tenuous cooperation among scientists. This is reported by most of the researchers, who deplore the lack of cooperation among their group. Relationships are mostly with the Ph.D. students and only marginally with colleagues. Our research shows that the more brilliant the scientists, the more frustrated they are from scientific institutions in Iran. Medium-range researchers seem to be much happier about the scientific institution to which they belong than the brighter scholars. The scientific institutions in Iran seem to be built for the needs of the former rather than the latter. These institutions seem not to play a positive role in the case of the best scientists. On the whole, many ingredients of the scientific community, at least at its inception, are present among Iranian scientists: the strong desire for scientific achievement in spite of personal, institutional and economic problems.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Poor workplace relations are an issue of concern in many workplaces and this phenomenon is not restricted to the nursing profession. The issue of workplace violence in nursing is well documented and there are an increasing number of studies which have investigated the notion of horizontal violence amongst graduate nurses. The impact that poor workplace relations has on the development of a professional identity by nursing students in the off-campus clinical setting is significant in light of the current global shortage of nurses. There is a dearth of knowledge in understanding how Australian undergraduate nursing students experience the off-campus clinical setting and subsequently develop a professional identity as a nurse. Therefore the aim of this study was to discover and describe the phenomena in order to develop a substantive theory that explains the experiences of the undergraduate nursing students in a regional setting. Constructivist grounded theory methods were utilised in the conduct of the study. A sample of 29 participants was recruited permitting the formulation of a substantive theory regarding the development of a professional identity in nursing students. This substantive theory contributes knowledge relevant to the undergraduate nursing students, nurse educators, nursing workforce planners, and the tertiary educational institutions offering nursing. This is achieved through discovering, describing and explaining the phenomenon of ‘anxiety’ which the nursing students experience as a result of the interrelationship and interactions of tradition bearing, staff and student performance. These interactions intersect to form expectations of where the student fits within the hierarchy of the facility and the nursing profession in general. An understanding of the issues associated with tradition bearing, staff performance, and student performance and the impact that the interaction of these conditions has upon the student’s developing professional identity as a nurse is necessary to allow for the implementation of corrective strategies.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

the (dis)orientation of thought in its encounter with art can be understood as the direct result of an encounter with indeterminacy as a lack in meaning. As an artist I am aware of how this indeterminacy impacts on the perceived value and authority of the artistic voice and in particular its value as a research voice. This paper explores this indeterminacy of meaning, as a profound and disturbing unknowing characteristic of the sublime and argues its value to advanced thought and for any methodological understanding of practice-led research. Lyotard described the sublime as an ‘understanding’ through which art and its associated practices may be able to resist an all too easy assimilation by the public as just a consumer commodity. His thought represents an attempt to both politically and philosophically understand art’s, and particularly abstract painting’s, affect as a state of profound and positive unknowing. To talk of the sublime in art is to speak of the suspension of any comfortable certainty in being and instead to engage with the real as a limit to meaning and knowing. It is to talk of the presentation of the unpresentable as a momentary but significant dissolution of representation. This understanding of the sublime is then further explored through the cultural phenomena of the monochrome painting and applied to the work of the two contemporary artists, Franz Erhard Walter and Günter Umberg. Initially the monochrome was understood as an attempt to go beyond traditional representation and present the unpresentable. In the one hundred years or so since that initial move this understanding has broadened. The monochrome now presents itself as a genre or even project within visual art but it still has much to teach us. In the concretely abstract and performative artworks of Franz Erhard Walter and Günter Umberg, traces of this ambition remain and their work can be seen to pose questions probing our understandings and experiences of artistic meaning, its value and the real.