53 resultados para Koninklikje Akademie van Wetenschappen (Netherlands)
em QUB Research Portal - Research Directory and Institutional Repository for Queen's University Belfast
Resumo:
Two cores of mid-Holocene raised-bog deposits from the Netherlands were 14C wiggle-match dated at high precision. Changes in local moisture conditions were inferred from the changing species composition of consecutive series of macrofossil samples. Several wet-shifts were inferred, and these were often coeval with major rises in the D14C archive (probably caused by major declines in solar activity). The use of D14C as a proxy for changes in solar activity is validated. This paper adds to the increasing body of evidence that solar variability forced climatic changes during the Holocene.
Resumo:
Recently, Bayesian statistical software has been developed for age-depth modeling (wiggle-match dating) of sequences of densely spaced radiocarbon dates from peat cores. The method is described in non-statistical terms, and is compared with an alternative method of chronological ordering of 14C dates. Case studies include the dating of the start of agriculture in the northeastern part of the Netherlands, and of a possible Hekla-3 tephra layer in the same country. We discuss future enhancements in Bayesian age modeling.
Resumo:
Lessen uit een lang vergeten crisis voor hedendaagse beleidsmakers en banken.
Resumo:
Recent years have seen the emergence of a markedly more critical discourse in the Netherlands as regards European integration. Concerns over both the size of the net national contribution to the European Union budget and the implications for the country of EU enlargement have given rise to high-profile public debates. An explicitly articulated discourse of national interest, centred on but not limited to the Liberal VVD, has become a staple of political debate. At the same time, movements with clearly Eurosceptic agendas (the Pim Fortuyn List and the Socialist Party) have enjoyed unparalleled levels of electoral success. Although not of significant electoral salience, 'Europe' has nevertheless emerged as an issue in Dutch politics. The present article examines these stirrings of dissent in an EU member state which had long been regarded as one of the most enthusiastic supporters of further integration.
Resumo:
: Static calculation and preliminary kinetic Monte Carlo simulation studies are undertaken for the nucleation and growth on a model system which follows a Frank-van der Merwe mechanism. In the present case, we consider the deposition of Ag on Au(100) and Au(111) surfaces. The interactions were calculated using the embedded atom model. The kinetics of formation and growth of 2D Ag structures on Au(100) and Au(111) is investigated and the influence of surface steps on this phenomenon is studied. Very different time scales are predicted for Ag diffusion on Au(100) and Au(111), thus rendering very different regimes for the nucleation and growth of the related 2D phases. These observations are drawn from the application of a model free of any adjustable parameter.
Resumo:
The chaotic profile of dust grain dynamics associated with dust-acoustic oscillations in a dusty plasma is considered. The collective behaviour of the dust plasma component is described via a multi-fluid model, comprising Boltzmann distributed electrons and ions, as well as an equation of continuity possessing a source term for the dust grains, the dust momentum and Poisson's equations. A Van der Pol–Mathieu-type nonlinear ordinary differential equation for the dust grain density dynamics is derived. The dynamical system is cast into an autonomous form by employing an averaging method. Critical stability boundaries for a particular trivial solution of the governing equation with varying parameters are specified. The equation is analysed to determine the resonance region, and finally numerically solved by using a fourth-order Runge–Kutta method. The presence of chaotic limit cycles is pointed out.