Certain Models (certain + models)

Distribution by Scientific Domains
Humanities and Social Sciences40%

Selected Abstracts

Parameter estimation accuracy analysis for induction motors

EUROPEAN TRANSACTIONS ON ELECTRICAL POWER, Issue 2 2005
E. Laroche
Abstract Various analytical dynamic models of induction machines, some of which take magnetic saturation and iron loss into account, are available in the literature. When parameter estimation is required, models must not only be theoretically identifiable but allow for accurate parameter estimation as well. This paper presents a comparison of parameter estimation accuracies obtained using different models and sets of measurements in the case of steady-state sinusoidal measurements. An explicit expression of estimation error is established and evaluated with respect to several measurement and modelling errors. This study will show that certain models are better suited for identification purposes than others and that certain sensors are bound to be more accurate than others. Lastly, an optimal experimental design procedure is implemented in order to derive an improved measurement set that leads to reduced estimation errors. Copyright © 2005 John Wiley & Sons, Ltd. [source]

Tutors and Pupils: International Organizations, Central European Elites, and Western Models

GOVERNANCE, Issue 2 2001
Wade Jacoby
In the past decade, political elites in Central and Eastern Europe have often sought to imitate Western organizational and institutional models, while organizations like the EU and NATO have often acted as "institutional tutors" in the region. Using evidence from Hungary and the Czech Republic, this paper demonstrates why imitating Western structures has been both administratively expedient and useful in building political coalitions. It also stresses that the short-term benefits of doing so are followed by longer-term costs. The paper answers four questions: How have certain models been held up to CEE elites? Why might some such models be targets for elites to imitate? How does such imitation occur? And what results from imitation? Contrary to expectations that institutional modeling would be merely technocratic and used only yearly in the transformation, the paper's threefold heuristic of templates, thresholds, and adjustments shows that the process is both politically contentious and sustained. [source]

Non-homogeneous Navier,Stokes systems with order-parameter-dependent stresses

MATHEMATICAL METHODS IN THE APPLIED SCIENCES, Issue 13 2010
Helmut Abels
Abstract We consider the Navier,Stokes system with variable density and variable viscosity coupled to a transport equation for an order-parameter c. Moreover, an extra stress depending on c and ,c, which describes surface tension like effects, is included in the Navier,Stokes system. Such a system arises, e.g. for certain models of granular flows and as a diffuse interface model for a two-phase flow of viscous incompressible fluids. The so-called density-dependent Navier,Stokes system is also a special case of our system. We prove short-time existence of strong solution in Lq -Sobolev spaces with q>d. We consider the case of a bounded domain and an asymptotically flat layer with a combination of a Dirichlet boundary condition and a free surface boundary condition. The result is based on a maximal regularity result for the linearized system. Copyright © 2010 John Wiley & Sons, Ltd. [source]

WHAT DIFFERENCE DOES IT MAKE?

RATIO, Issue 4 2006
THE NATURE AND SIGNIFICANCE OF THEISTIC BELIEF
Theism is often supposed to be distinguished from atheism by the heavy weight of metaphysical belief that it carries. This paper argues that this is not as illuminating a way of distinguishing the theist's from the atheist's outlook as is often supposed. The key divergence consists not so much in matters of theoretical belief or philosophical argument as in practical differences in affective response and in the adoption of certain models for living. Two characteristically religious virtues, humility and hope, and two distinctively religious responses, awe and thanksgiving, are discussed in order to illustrate this. The paper's conclusion, while not denying a cognitive core to theism, argues that warranted assent to the metaphysical truth of God's existence cannot be a precondition for theistic hermeneusis and praxis.1 [source]

Downregulation of cell survival signalling pathways and increased cell damage in hydrogen peroxide-treated human renal proximal tubular cells by alpha-erythropoietin

CELL PROLIFERATION, Issue 4 2009
M. Andreucci
Objective:, Erythropoietin has been shown to have a protective effect in certain models of ischaemia-reperfusion, and in some cases the protection has been correlated with activation of signalling pathways known to play a role in cell survival and proliferation. We have studied whether erythropoietin would overcome direct toxic effects of hydrogen peroxide (H2O2) treatment to human renal proximal tubular (HK-2) cells. Materials and methods:, HK-2 cells were incubated with H2O2 (2 mm) for 2 h with or without erythropoietin at concentrations of 100 and 400 U/ml, and cell viability/proliferation was assessed by chemical reduction of MTT. Changes in phosphorylation state of the kinases Akt, glycogen synthase kinase-3, (GSK-3,), mammalian target of rapamycin (mTOR) and extracellular signal-regulated kinase 1 and 2 (ERK1/ERK2) were also analysed. Results:, Cells incubated with H2O2 alone showed a significant decrease in viability, which did not significantly change by addition of erythropoietin at concentration of 100 U/ml, but was further reduced when concentration of erythropoietin was increased to 400 U/ml. Phosphorylation state of the kinases Akt, GSK-3,, mTOR and ERK1/ERK2 of H2O2 -treated HK-2 cells was slightly altered in the presence of erythropoietin at concentration of 100 U/ml, but was significantly less in the presence of erythropoietin at a concentration of 400 U/ml. Phosphorylation of forkhead transcription factor FKHRL1 was diminished in cells incubated with H2O2 and erythropoietin at a concentration of 400 U/ml. Conclusions:, Erythropoietin, at high concentrations, may significantly increase cellular damage in HK-2 cells subjected to oxidative stress, which may be due in part to decrease in activation of important signalling pathways involved in cell survival and/or cell proliferation. [source]