880 resultados para Variational inequalities


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We investigate the violation of noncontextuality by a class of continuous-variable states, including variations of entangled coherent states and a two-mode continuous superposition of coherent states. We generalize the Kochen-Specker (KS) inequality discussed by Cabello [A. Cabello, Phys. Rev. Lett. 101, 210401 (2008)] by using effective bidimensional observables implemented through physical operations acting on continuous-variable states, in a way similar to an approach to the falsification of Bell-Clauser-Horne-Shimony-Holt inequalities put forward recently. We test for state-independent violation of KS inequalities under variable degrees of state entanglement and mixedness. We then demonstrate theoretically the violation of a KS inequality for any two-mode state by using pseudospin observables and a generalized quasiprobability function.

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We investigate the violation of Leggett's inequality for nonlocal realism using entangled coherent states and various types of local measurements. We prove mathematically the relation between the violation of the Clauser-Horne-Shimony-Holt form of Bell's inequality and Leggett's one when tested by the same resources. For Leggett inequalities, we generalize the nonlocal realistic bound to systems in Hilbert spaces larger than bidimensional ones and introduce an optimization technique that allows one to achieve larger degrees of violation by adjusting the local measurement settings. Our work describes the steps that should be performed to produce a self-consistent generalization of Leggett's original arguments to continuous-variable states.

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Some thermodynamical properties of solids, such as heat capacity and magnetic susceptibility, have recently been shown to be linked to the amount of entanglement in a solid. However, this entanglement may appear a mere mathematical artefact of the typical symmetrization procedure of many-body wavefunction in solid state physics. Here we show that this entanglement is physical, demonstrating the principles of its extraction from a typical solid-state system by scattering two particles off the system. Moreover, we show how to simulate this process using present day optical lattice technology. This demonstrates not only that entanglement exists in solids but also that it can be used for quantum information processing or as a test of Bell's inequalities.

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This paper explores relationships between classical and parametric measures of graph (or network) complexity. Classical measures are based on vertex decompositions induced by equivalence relations. Parametric measures, on the other hand, are constructed by using information functions to assign probabilities to the vertices. The inequalities established in this paper relating classical and parametric measures lay a foundation for systematic classification of entropy-based measures of graph complexity.

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Several studies have shown social differences in alcohol consumption, and social inequalities of harm related to alcohol use and abuse. However, relationships between the position in the socio-economic spectrum, alcohol use, and alcohol-related health problems are not clear cut. While there is some evidence of social gradients or associations between indicators of deprivation and some adolescence outcomes (e.g. externalising behaviour), the evidence regarding associations between socio-economic status and alcohol-related problems in adolescence is more conflicting. A major problem in studying socio-economic inequalities in adolescent health is related to the paucity of measures of socio-economic status in adolescence that are both conceptually and methodologically sound.
The aims of this study were to investigate socio-economic differences in pathways from onset to establishment of drinking patterns in adolescence, assess the consequences of these pathways in terms of alcohol related harm, and to consider the causal mechanisms that may contribute to socio-economic differences in drinking pathways and outcomes

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While there are many case studies looking at gender mainstreaming in national contexts, this article offers a pan-European perspective to examine how a stated commitment to gender equality at this meta-level works in practice. The European Union’s (EU) stated commitment to gender mainstreaming the Common Agricultural Policy (CAP) is critically reviewed. The article reviews theoretical literature on gender mainstreaming, considers the position of women in agriculture across Europe, and examines efforts by the EU to gender mainstream the CAP. It argues that at best, gender mainstreaming focuses on the symptoms of gender inequality in agriculture rather than the causes. Because of this, gender mainstreaming cannot be transformative in this context. Little thought has been given to the practical difficulties of actually gender mainstreaming a policy such as the CAP. The EU’s priority for the CAP focuses on the mainstream business goal of a viable agricultural industry and does not pay any heed to gender inequalities in agriculture. In short, the stated commitment to gender mainstreaming is empty rhetoric

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The capacity to provide satisfactory nursing care is being increasingly compromised by current trajectories of healthcare funding and governance. The purpose of this paper is to examine how well Marxist theories of the state and its relationship with capital can explain these trajectories in this period of ever-increasing austerity. Following a brief history of the current crisis, it examines empirically the effects of the crisis, and of the current trajectory of capitalism in general, upon the funding and organization of the UK and US healthcare systems. The deleterious effect of growing income inequalities to the health of the population are also addressed. Marx’s writings on the state and its relation to the capitalist class were fragmentary, and historically and geographically specific. From them, we can extract three theoretical variants: the instrumentalist theory of the state, where the state has no autonomy from capital; the abdication theory, whereby capital abstains from direct political power and relies on the state to serve its interests; and the class-balance theory of the state, whereby the struggle between two opposed classes allows the state to assert itself. Discussion of modern Marxist interpretations include Poulantzas’s structuralist abdication theory and Miliband’s instrumentalist theory. It is concluded that, despite the pluralism of electoral democracies, the bourgeoisie do have an overweening influence upon the state. The bourgeoisie’s ownership of the means of production provides the foundation for its influence because the state is obliged to rely on it to manage the supply of goods and services and the creation of wealth. That power is further reinforced by the infiltration of the bourgeoisie into the organs of state. The level of influence has accelerated rapidly over recent decades. One of the consequences of this has been that healthcare systems have become rich pickings for the evermore confident bourgeoisie.

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In this paper we address the question of the relative importance of within and between country differences in income and material deprivation in the European Union in the context of recent suggestions that insufficient attention has been paid to the latter. In particular, we respond to the argument that the 'state bounded' relative income approach obscures the significance of EU-wide reference groups. Making use of EU-SILC 2004, we have sought to quantify the magnitude of relevant within and between country differences and their relative impact. Overall, our analysis supports the view that the predominant frame of reference is a national one. The limited impact of European reference groups observed in our analysis does not require explanation in terms of the emergence of a European social stratification system. Furthermore, the significance of such comparisons depends not only on the expectations of those affected by European inequalities but on the degree of legitimacy afforded to ensuing demands. While an EU-wide income-threshold can provide information regarding progress of the Union towards greater social cohesion, its usage for this purpose does not require a strong sense of European identity. Given the current status of the European Social Model, it would seem unwise to attribute an undue degree of policy relevance to the relatively modest impact of EU-wide reference groups revealed in our analysis.

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In this paper we seek to update findings relating to class mobility outcomes and processes in the Republic of Ireland employing data from the Living in Ireland Survey which was carried out in 1994. We also provide an evaluation of a measured variable model of the mobility process developed on an earlier data set. Our findings confirm that transformation of the class structure has been associated with substantial levels of social mobility. At the same time inequalities of opportunity as reflected in the underlying patterns of social fluidity remain substantial and are constant across cohorts. Gender differences are almost entirely a consequence of occupational segregation and there is no evidence that the underlying processes of class disadvantage operate differently for men and women.

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Attempts to explain variation in rates of psychological distress by social class have included reference to social selection, differential exposure to stress, and differential vulnerability arising from inequalities in access to resources. Our analysis draws on data from a national survey of the Republic of Ireland in order to examine these hypotheses. No evidence to support the social selection hypothesis was found. In addressing the issue of differential responsiveness, attention was focused on the interaction between unemployment and social class in their impact on psychological distress. While rather weak support for the hypothesis of differential vulnerability was found among women, our examination of the impact of husband's unemployment provided no evidence leading in this direction. Among men unemployment actually had a stronger impact for men in higher social classes. The major factors leading to social class differences in psychological distress are greater exposure to unemployment and economic deprivation. © 1994 Oxford University Press.

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Dermot Bolger's The Journey Home (1990) narrates an often hyperbolic and overblown diatribe against a litany of social and political ills, which elicited frequently critical responses to the novel from reviewers. Yet Bolger's seminal work remains both popular and controversial because of its capacity to shock and upbraid the false morality of Irish society--a society that the author considered to be riven by class inequalities and official abuses. Bolger employs sexual abuse as a metonym for political corruption in the novel, and this essay explores The Journey Home's surreal story of youth in a working-class Dublin suburb in light of more recent revelations of Ireland's legacy of institutional sexual abuse.

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EUROCHIP (European Cancer Health Indicators Project) focuses on understanding inequalities in the cancer burden, care and survival by the indicators "stage at diagnosis," "cancer treatment delay" and "compliance with cancer guidelines" as the most important indicators. Our study aims at providing insight in whether cancer registries collect well-defined variables to determine these indicators in a comparative way. Eighty-six general European population-based cancer registries (PBCR) from 32 countries responded to the questionnaire, which was developed by EUROCHIP in collaboration with ENCR (European Network of Cancer Registries) and EUROCOURSE. Only 15% of all the PBCR in EU had all three indicators available. The indicator "stage at diagnosis" was gathered for at least one cancer site by 81% (using TNM in 39%). Variables for the indicator "cancer treatment delay" were collected by 37%. Availability of type of treatment (30%), surgery date (36%), starting date of radiotherapy (26%) and starting date of chemotherapy (23%) resulted in 15% of the PBCRs to be able to gather the indicator "compliance to guidelines". Lack of data source access and qualified staff were the major reasons for not collecting all the variables. In conclusion, based on self-reporting, a few of the participating PBCRs had data available which could be used for clinical audits, evaluation of cancer care projects, survival and for monitoring national cancer control strategies. Extra efforts should be made to improve this very efficient tool to compare cancer burden and the effects of the national cancer plans over Europe and to learn from each other. © 2012 UICC.

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The solution of the time-dependent Schrodinger equation for systems of interacting electrons is generally a prohibitive task, for which approximate methods are necessary. Popular approaches, such as the time-dependent Hartree-Fock (TDHF) approximation and time-dependent density functional theory (TDDFT), are essentially single-configurational schemes. TDHF is by construction incapable of fully accounting for the excited character of the electronic states involved in many physical processes of interest; TDDFT, although exact in principle, is limited by the currently available exchange-correlation functionals. On the other hand, multiconfigurational methods, such as the multiconfigurational time-dependent Hartree-Fock (MCTDHF) approach, provide an accurate description of the excited states and can be systematically improved. However, the computational cost becomes prohibitive as the number of degrees of freedom increases, and thus, at present, the MCTDHF method is only practical for few-electron systems. In this work, we propose an alternative approach which effectively establishes a compromise between efficiency and accuracy, by retaining the smallest possible number of configurations that catches the essential features of the electronic wavefunction. Based on a time-dependent variational principle, we derive the MCTDHF working equation for a multiconfigurational expansion with fixed coefficients and specialise to the case of general open-shell states, which are relevant for many physical processes of interest. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3600397]

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The electronic and vibrational properties of CO adsorbed on Pt electrodes at different potentials have been studied, by using methods of self-consistent-charge discrete variational Xa (SCC-DV-Xa) cluster calculations and in situ FTir spectroscopy. Two new models have been developed and verified to be successful: (1) using a "metallic state cluster" to imitate a metal (electrode) surface; and (2) charging the cluster and shifting its Fermi level (e{lunate}) to simulate, according to the relation of -d e{lunate}e dE, quantitatively the variation of the electrode potential (E). It is shown that the binding of PtCO is dominated by the electric charge transfer of dp ? 2p, while that of s ? Pt is less important in this binding. The electron occupancy of the 2p orbital of CO weakens the CO bond and decreases the v. Variation of E mainly influences the charge transfer process of dp ? 2p, but hardly influences that of s ? Pt. A linear potential-dependence of v has been shown and the calculated dv/dE = 35.0 cm V. All results of calculations coincide with the ir experimental data. © 1993.

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The electronic properties of CN adsorbed on Ag electrodes at different potentials have been studied by using the method of self-consistent-charge discrete variational Xa (SCC-DV-Xa) cluster calculations. It is shown that the binding of NCAg is dominated by both electrostatic and polarization effects derived from the charge of CN, and that the transfer of s charge from CN to silver is the largest donation contribution. The electrode potential influences this charge transfer process and the interaction between CN adsorbate and silver electrode. The results of quantum chemistry calculations fit well with the experimental data of in situ spectroscopic studies on the CN/Ag electrode systems. © 1991.