A first approach toward Bayesian estimation of turbulent plasma properties from reflectometry

The possibility of inferring the properties of electron density fluctuations in tokamak plasmas from a reflectometer signal by means of Bayesian methods is investigated. Within the physical optics approximation, the interaction of the probing beam with the plasma is described as reflection from a surface with stochastic properties that is simulated numerically. A Bayesian technique is outlined to solve the inverse problem to determine the surface characteristics from the power spectrum of the reflectometer signal. It is shown that satisfactory estimates of the length and timescales and the amplitude of density fluctuations can be obtained in conditions relevant to core tokamak plasmas.

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Spatial and temporal changes of prehistoric human land use in the Wei valley, northern China

Agricultural land use has been established as the dominant prehistoric human activity in early cultural centers for thousands of years. However, because of lack of data, there is still considerable debate about the amount and spatial distribution of prehistoric land use across the world. Quantitative reconstruction of it on the basis of human activity records, for example, archaeological data, is the key to resolving the issue. Here, we focus on one of the most representative regions for prehistoric human activity in northern China, the Wei River valley. Based on archaeological and environmental data, a recently developed quantitative prehistoric land use model (PLUM) is applied to reconstruct spatial and temporal changes of land use between 8 and 4 ka BP. The results reveal that in line with increases in the total number of archaeological sites (from 24 to 3222) and population (from 4000 to 1,550,000), the land area of the valley used by humans increased from 0.2% to 12% during the study interval, expanding from the gentle slopes along the lower reaches of the river to the middle and upper reaches. Meanwhile, the average population for an individual site increased from 160 to 481, but the average land use area per site decreased from 12.84 to 4.68 km2. Since 6 ka BP, the significant land use increase occurred synchronously in the Wei River valley and other key regions of agricultural origin across the world, which highlights the important role of agriculture activity in transforming the nature of global land cover during the prehistoric period.

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The European Union’s 'Comprehensive approach' in Chad: securitisation and/or compartmentalisation?

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Carbon and energy fluxes in cropland ecosystems: a model-data comparison

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Overview of the JET results

Since the installation of an ITER-like wall, the JET programme has focused on the consolidation of ITER design choices and the preparation for ITER operation, with a specific emphasis given to the bulk tungsten melt experiment, which has been crucial for the final decision on the material choice for the day-one tungsten divertor in ITER. Integrated scenarios have been progressed with the re-establishment of long-pulse, high-confinement H-modes by optimizing the magnetic configuration and the use of ICRH to avoid tungsten impurity accumulation. Stationary discharges with detached divertor conditions and small edge localized modes have been demonstrated by nitrogen seeding. The differences in confinement and pedestal behaviour before and after the ITER-like wall installation have been better characterized towards the development of high fusion yield scenarios in DT. Post-mortem analyses of the plasma-facing components have confirmed the previously reported low fuel retention obtained by gas balance and shown that the pattern of deposition within the divertor has changed significantly with respect to the JET carbon wall campaigns due to the absence of thermally activated chemical erosion of beryllium in contrast to carbon. Transport to remote areas is almost absent and two orders of magnitude less material is found in the divertor.

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Verloopt de nucleaire en cytoplasmatische maturatie van in vitro gerijpte eicellen synchroon?

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Invloed van equien groeihormoon (eCG) tijdens de in vitro maturatie van paardeneicellen

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