948 resultados para Model driven developments


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A scanning tunneling microscope can probe the inelastic spin excitations of a single magnetic atom in a surface via spin-flip assisted tunneling in which transport electrons exchange spin and energy with the atomic spin. If the inelastic transport time, defined as the average time elapsed between two inelastic spin flip events, is shorter than the atom spin-relaxation time, the scanning tunnel microscope (STM) current can drive the spin out of equilibrium. Here we model this process using rate equations and a model Hamiltonian that describes successfully spin-flip-assisted tunneling experiments, including a single Mn atom, a Mn dimer, and Fe Phthalocyanine molecules. When the STM current is not spin polarized, the nonequilibrium spin dynamics of the magnetic atom results in nonmonotonic dI/dV curves. In the case of spin-polarized STM current, the spin orientation of the magnetic atom can be controlled parallel or antiparallel to the magnetic moment of the tip. Thus, spin-polarized STM tips can be used both to probe and to control the magnetic moment of a single atom.

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Purpose: The P23H rhodopsin mutation is an autosomal dominant cause of retinitis pigmentosa (RP). The degeneration can be tracked using different anatomical and functional methods. In our case, we evaluated the anatomical changes using Spectral-Domain Optical Coherence Tomography (SD-OCT) and correlated the findings with retinal thickness values determined by immunocytochemistry.Methods: Pigmented rats heterozygous for the P23H mutation, with ages between P18 and P180 were studied. Function was assessed by means of optomotor testing and ERGs. Retinal thicknesses measurements, autofluorescence and fluorescein angiography were performed using Spectralis OCT. Retinas were studied by means of immunohistochemistry. Results: Between P30 and P180, visual acuity decreased from 0.500 to 0.182 cycles per degree (cyc/deg) and contrast sensitivity decreased from 54.56 to 2.98 for a spatial frequency of 0.089 cyc/deg. Only cone-driven b-wave responses reached developmental maturity. Flicker fusions were also comparable at P29 (42 Hz). Double flash-isolated rod-driven responses were already affected at P29. Photopic responses revealed deterioration after P29.A reduction in retinal thicknesses and morphological modifications were seen in OCT sections. Statistically significant differences were found in all evaluated thicknesses. Autofluorescence was seen in P23H rats as sparse dots. Immunocytochemistry showed a progressive decrease in the outer nuclear layer (ONL), and morphological changes. Although anatomical thickness measures were significantly lower than OCT values, there was a very strong correlation between the values measured by both techniques.Conclusions: In pigmented P23H rats, a progressive deterioration occurs in both retinal function and anatomy. Anatomical changes can be effectively evaluated using SD-OCT and immunocytochemistry, with a good correlation between their values, thus making SD-OCT an important tool for research in retinal degeneration.

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There is a certain arrogance in the affirmation that a “European model” of regional integration and of compliance with international law should be adopted anywhere in the world, and in Asia in particular. This article argues on the contrary that Asia and Europe are in fundamentally different situations vis-à-vis international law. Based on an analysis of recent events and latest legal developments in Europe, it puts the “European model” of regional integration and the European selective compliance with international law in perspective with regard to the Asian context. Without denying that “civilizations” should learn from one another and that the European experience may be relevant to some extent in Asia, this article concludes that the tools developed in Europe should be used differently in Asia.

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The significant gains in export market shares made in a number of vulnerable euro-area crisis countries have not been accompanied by an appropriate improvement in price competitiveness. This paper argues that, under certain conditions, firms consider export activity as a substitute for serving domestic demand. The strength of the link between domestic demand and exports is dependent on capacity constraints. Our econometric model for six euro-area countries suggests domestic demand pressure and capacity-constraint restrictions as additional variables of a properly specified export equation. As an innovation to the literature, we assess the empirical significance through the logistic and the exponential variant of the non-linear smooth transition regression model. We find that domestic demand developments are relevant for the short-run dynamics of exports in particular during more extreme stages of the business cycle. A strong substitutive relationship between domestic and foreign sales can most clearly be found for Spain, Portugal and Italy, providing evidence of the importance of sunk costs and hysteresis in international trade.

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This study analyzes the Turkish case as a model country for the state-building processes in the Arab world in the aftermath of the Arab revolts that took place in Tunisia, Egypt and Libya. To this end, it deals with the Turkish case in three phases: the founding of the Turkish Republic, political developments until 2002, and the post-2002 Justice and Development Party period. The study focuses on state-society relations manifested in the form of a secular-religious cleavage intertwined with problematic civil-military relations. Each phase of Turkey’s history is compared to cleavages and civil-military relations in Egypt, Tunisia and Libya. After analyzing the constitution-making processes in the latter three countries following the Arab revolts, the study concludes by discussing the viability of the Turkish model in the light of Turkey’s search for a new constitution.

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The question of Kosovo's status is currently one of the most important issues in international politics. Since 1999, Kosovo has been an international protectorate which was created in the aftermath of the NATO intervention to stop the brutal pacification of the Albanian insurgency by Serb forces. The province has since de facto become independent of Serbia. Resolution 1244 of the UN Security Council, which established the protectorate, does not preclude any possible outcome as regards its status. Aware that after the crimes of 1999, any attempt to re-integrate Kosovo into Serbia would lead to a massive Albanian uprising, the West has decided that the best solution would be to award Kosovo internationally supervised independence, while at the same time granting very wide autonomy to the Kosovo Serbs. Serbia and Russia rejected the solution proposed by the West, and so Kosovo became an arena of international rivalry for influence in the Western Balkans as well as another element of rivalry, transcending the regional dimension, between Russia and the West. Russia has been using the Kosovo case to build a new model of its relations with the United States and the EU. Since there is a group of countries sceptical about, or even opposed to, Kosovo's independence within the EU, the Kosovo settlement will be a test of the EU's ability to speak with one voice with regard to its external policy.

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Four alternative macroeconomic scenarios for southern Mediterranean countries are quantified in this study with the use of GEM-E3, a general equilibrium model. These are i) the continuation of current policies (business-as-usual scenario), ii) southern Mediterranean–EU cooperation (Euro-Mediterranean Union scenario), iii) a global opening of the southern Mediterranean countries and cooperation with the rest of the Middle East and other developing countries like China (Euro-Mediterranean alliance scenario), and iv) a deterioration in the regional political climate and a failure of cooperation (Euro-Mediterranean under threat scenario). Explicit assumptions on trade integration, infrastructure upgrade, population and governance developments are adopted in each scenario. The simulation results indicate that an infrastructure upgrade and governance improvements in the context of southern Mediterranean–EU cooperation could benefit most of the countries under consideration. The analysis remains important in light of ongoing regional developments and the need to design the best policies to pursue in the aftermath of the Arab spring.

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This paper explores the incentives political and bureaucratic actors face in the institutional setting of EU technology policy. In examining the implications and assumptions of neoclassical and evolutionary theories of technological change, it tries to answer why certain theories do not obtain importance in the political wor1d. By focusing on the positive approach to policymaking, the paper examines why policy learning does not occur m certain institutional settings. In referring to EU technology programs, I show which conceptual and functional shortcomings limit the policies in question. As evaluation and oversight mechanisms have not been sufficiently developed and accepted within the institutional setting, there is much room for inefficiency. I discuss this setting within a simple agency model using two political actors and two firms performing R&D. It is easy to show that when asymmetric information applies, the firms receive positive rents and the political agent gains reputation. The outcome suggests changing the evaluation practices and embedding results in political decision making. Regarding this point, recent U.S. developments seem to have led to more efficiency. Moreover, the paper suggests delegating technology policy to other actors and discussing the empowerment of different principals on the political plane.

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The strength model of self-control assumes that all acts of self-control (e.g., emotion regulation, persistence) are empowered by a single global metaphorical strength that has limited capacity. This strength can become temporarily depleted after a primary self-control act, which, in turn, can impair performance in subsequent acts of self-control. Recently, the assumptions of the strength model of self-control also have been adopted and tested in the field of sport and exercise psychology. The present review paper aims to give an overview of recent developments in self-control research based on the strength model of self-control. Furthermore, recent research on interventions on how to improve and revitalize self-control strength will be presented. Finally, the strength model of self-control has been criticized lately, as well as expanded in scope, so the present paper will also discuss alternative explanations of why previous acts of self-control can lead to impaired performance in sport and exercise.

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Both long-term environmental changes such as those driven by the glacial cycles and more recent anthropogenic impacts have had major effects on the past demography in wild organisms. Within species, these changes are reflected in the amount and distribution of neutral genetic variation. In this thesis, mitochondrial and microsatellite DNA was analysed to investigate how environmental and anthropogenic factors have affected genetic diversity and structure in four ecologically different animal species. Paper I describes the post-glacial recolonisation history of the speckled-wood butterfly (Pararge aegeria) in Northern Europe. A decrease in genetic diversity with latitude and a marked population structure were uncovered, consistent with a hypothesis of repeated founder events during the postglacial recolonisation. Moreover, Approximate Bayesian Computation analyses indicate that the univoltine populations in Scandinavia and Finland originate from recolonisations along two routes, one on each side of the Baltic. Paper II aimed to investigate how past sea-level rises affected the population history of the convict surgeonfish (Acanthurus triostegus) in the Indo-Pacific. Assessment of the species’ demographic history suggested a population expansion that occurred approximately at the end of the last glaciation. Moreover, the results demonstrated an overall lack of phylogeographic structure, probably due to the high dispersal rates associated with the species’ pelagic larval stage. Populations at the species’ eastern range margin were significantly differentiated from other populations, which likely is a consequence of their geographic isolation. In Paper III, we assessed the effect of human impact on the genetic variation of European moose (Alces alces) in Sweden. Genetic analyses revealed a spatial structure with two genetic clusters, one in northern and one in southern Sweden, which were separated by a narrow transition zone. Moreover, demographic inference suggested a recent population bottleneck. The inferred timing of this bottleneck coincided with a known reduction in population size in the 19th and early 20th century due to high hunting pressure. In Paper IV, we examined the effect of an indirect but well-described human impact, via environmental toxic chemicals (PCBs), on the genetic variation of Eurasian otters (Lutra lutra) in Sweden. Genetic clustering assignment revealed differentiation between otters in northern and southern Sweden, but also in the Stockholm region. ABC analyses indicated a decrease in effective population size in both northern and southern Sweden. Moreover, comparative analyses of historical and contemporary samples demonstrated a more severe decline in genetic diversity in southern Sweden compared to northern Sweden, in agreement with the levels of PCBs found.

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

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The dynamical properties of an extended Hubbard model, which is relevant to quarter-filled layered organic molecular crystals, are analyzed. We have computed the dynamical charge correlation function, spectral density, and optical conductivity using Lanczos diagonalization and large-N techniques. As the ratio of the nearest-neighbor Coulomb repulsion, V, to the hopping integral, t, increases there is a transition from a metallic phase to a charge-ordered phase. Dynamical properties close to the ordering transition are found to differ from the ones expected in a conventional metal. Large-N calculations display an enhancement of spectral weight at low frequencies as the system is driven closer to the charge-ordering transition in agreement with Lanczos calculations. As V is increased the charge correlation function displays a collective mode which, for wave vectors close to (pi,pi), increases in amplitude and softens as the charge-ordering transition is approached. We propose that inelastic x-ray scattering be used to detect this mode. Large-N calculations predict superconductivity with d(xy) symmetry close to the ordering transition. We find that this is consistent with Lanczos diagonalization calculations, on lattices of 20 sites, which find that the binding energy of two holes becomes negative close to the charge-ordering transition.