Lindblad Approach to Nonlinear Jaynes-Cummings Dynamics of a Trapped Ion

The Lindblad approach to open quantum systems is introduced for studying the dynamics of a single trapped ion prepared in nonclassical motional states and subjected to continuous measurement of its internal population. This results in an inhibition of the dynamics similar to the one occurring in the quantum Zeno effect. In particular, modifications to the Jaynes-Cummings collapses and revivals arising from an initial coherent state of motion in various regimes of interaction with the driving laser are dealt in detail.Comment: 5 Pages, 3 figures available upon request; Plain REVTeX; to be published in Physical Review

Network-aware video streaming for future media Internet

272 p

Pragmatism and the Writing of History

The contributions presented in this symposium explore, from different perspectives, the relationship between pragmatism and history, that is, the empirical study of the human past. These connections run deep, and may be assessed on several counts. First of all, many pragmatist philosophers have devoted a great deal of attention to investigating the nature of historical knowledge and its relevance to philosophy. Classical pragmatists such as Peirce, Dewey and Mead laid a strong emphasis on pro..

Measured Quantum Dynamics of a Trapped Ion

The measurement process is taken into account in the dynamics of trapped ions prepared in nonclassical motional states. The induced decoherence is shown to manifest itself both in the inhibition of the internal population dynamics and in a damping of the vibrational motion without classical counterpart. Quantitative comparison with present experimental capabilities is discussed, leading to a proposal for the verification of the predicted effects.Comment: 5 Pages, no figures; Plain REVTeX; to be published in the 1st May issue of Phys. Rev. A, Rap. Commun. (1997

Retention performance of green roofs in representative climates worldwide

The ongoing process of global urbanization contributes to an increase in stormwater runoff from impervious surfaces, threatening also water quality. Green roofs have been proved to be innovative stormwater management measures to partially restore natural states, enhancing interception, infiltration and evapotranspiration fluxes. The amount of water that is retained within green roofs depends not only on their depth, but also on the climate, which drives the stochastic soil moisture dynamic. In this context, a simple tool for assessing performance of green roofs worldwide in terms of retained water is still missing and highly desirable for practical assessments. The aim of this work is to explore retention performance of green roofs as a function of their depth and in different climate regimes. Two soil depths are investigated, one representing the intensive configuration and another representing the extensive one. The role of the climate in driving water retention has been represented by rainfall and potential evapotranspiration dynamics. A simple conceptual weather generator has been implemented and used for stochastic simulation of daily rainfall and potential evapotranspiration. Stochastic forcing is used as an input of a simple conceptual hydrological model for estimating long-term water partitioning between rainfall, runoff and actual evapotranspiration. Coupling the stochastic weather generator with the conceptual hydrological model, we assessed the amount of rainfall diverted into evapotranspiration for different combinations of annual rainfall and potential evapotranspiration in five representative climatic regimes. Results quantified the capabilities of green roofs in retaining rainfall and consequently in reducing discharges into sewer systems at an annual time scale. The role of substrate depth has been recognized to be crucial in determining green roofs retention performance, which in general increase from extensive to intensive settings. Looking at the role of climatic conditions, namely annual rainfall, potential evapotranspiration and their seasonality cycles, we found that they drive green roofs retention performance, which are the maxima when rainfall and temperature are in phase. Finally, we provide design charts for a first approximation of possible hydrological benefits deriving from the implementation of intensive or extensive green roofs in different world areas. As an example, 25 big cities have been indicated as benchmark case studies

Modeling mitral valve stenosis:A parametric study on the stenosis severity level

New computational techniques providing more accurate representation of human heart pathologies could help uncovering relevant physical phenomena and improve the outcome of medical therapies. In this framework, the present work describes an efficient computational model for the evaluation of the ventricular flow alteration in presence of mitral valve stenosis. The model is based on the direct numerical simulation of the Navier–Stokes equations two-way coupled with a structural solver for the left ventricle and mitral valve dynamics. The presence of mitral valve stenosis is mimicked by a single-parameter constraint acting on the kinematics of the mitral leaflets. Four different degrees of mitral valve stenosis are considered focusing on the hemodynamic alterations occurring in pathologic conditions. The mitral jet, generated during diastole, is seen to shrink and strengthen when the stenosis gets more severe. As a consequence, the kinetic energy of the flow, the tissues shear stresses, the transvalvular pressure drop and mitral regurgitation increase. It results that, as the stenosis severity level increases, the geometric and effective orifice areas decrease up to 50% with respect the normal case due to the reduced leaflets mobility and stronger blood acceleration during the diastolic phase. The modified intraventricular hemodynamics is also related to a stronger pressure gradient that, for severe stenosis, can be more than ten times larger than the healthy valve case. These computational results are fully consistent with the available clinical literature and open the way to the virtual assessment of surgical procedures and to the evaluation of prosthetic devices

Comparative Public Law and Water Crisis. Environmental Cost, Participation, and Alternative Dispute Resolution

Environmental degradation and anthropogenic climate change severely affect natural resources, thus fostering the need for effective tools to cope with multiple concerns. Within this scenario, the article aims to address public law policies and legislation in reference to water management, with a focus on three specific issues: 1) environmental cost, 2) participation and water management, 3) alternative dispute resolutions (adr s) and water disputes. The first part is based on the analysis of environmental cost related to the degradation and exhaustion of water ecosystems as a result of an activity (e.g., as a result of withdrawal and/or pollution), as well as related to the supply scarcity. The second part deals with participation, co-participation and multi-level governance systems in the context of deliberative decision-making processes. The third part highlights the key role of participation and proximity in resolving disputes within local communities through the analysis of specific cases (i.e., the Tribunal de las Aguas, the Sudovi za vodu, and the Médiateur de l’eau

High-fidelity model of the human heart:An immersed boundary implementation

Computer simulations of cardiovascular flows can be key to improving the predicting capabilities of standard diagnostic tools, to refine surgical techniques and perform virtual tests of innovative prosthetic devices. The reliability of simulations, however, depends on the fidelity level of the model, which, for the heart, involves the interconnected multiphysics dynamics of the various systems: the human heart is among the most complex organs, and simulating its dynamics is an ambitious undertaking from both the modeling and computational viewpoints. In this paper we present a multiphysics computational model of the human heart accounting simultaneously for the electrophysiology, the elasto-mechanics, and the hemodynamics, including their multiway coupled interactions referred to as fluid-structure-electro interaction (FSEI). The developed tool embodies accuracy, versatility, and computational efficiency, thus allowing cardiovascular simulations of physiologic and pathologic configurations within a time to solution compatible with the clinical practice and without resorting to large-scale supercomputers. Results are shown for healthy conditions and for myocardial infarction with the aim of assessing the reliability of the model and proving its predicting capabilities, which could be used to anticipate the outcome of surgical procedures or support clinical decisions