Short-term constituents of the secular variation, at inter-decadal (20-30 years) and sub-centennial (60-90 years) time scales, present in observatory data and main field models, are also found in the radial field evolution at core surface. The paper is focused on the sub-centennial constituent in the gufm1 model. Time-Longitude (t-λ) plots, covering the 400 years time span of the model, at various latitudes between 70°N and 70°S, show a clear westward movement of the sub-centennial constituent field features in the 20°N-20°S latitude band. The sub-centennial constituent at latitudes larger than 50°N/S stands in fact for the fine structure of high-latitude flux lobes. Since 1900 this fine structure shows a westward displacement. Time-Latitude (t-φ) plots indicate also northward and southward components of the movement. The traveling speeds of the sub-centennial constituent field are derived, on one hand, empirically based on Time-Longitude and Time-Latitude plots, and on the other, mathematically by means of the Radon transform method. Important results of this paper are related to characterization of the evolution of the radial field at core surface at sub-centennial time scales, namely (1) evidencing two types of azimuthal flow, equatorial and high latitude ones, responsible for the observed westward drift of the surface field, and (2) quantitative information on meridional displacements of the core surface magnetic flux patches.

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The emergence of separate cemeteries for disposal of the dead represents a profound shift in mortuary practice in the Late Neolithic of southeast Europe, with a new emphasis on the repeated use of a specific space distinct from, though still often close to, settlements. To help to time this shift more precisely, this paper presents 25 dates from 21 burials in the large cemetery at Cernica, in the Lower Danube valley in southern Romania, which are used to formally model the start, duration of use and end of the cemetery. A further six dates were obtained from four contexts for the nearby settlement. Careful consideration is given to the possibility of environmental and dietary offsets. The preferred model, without freshwater reservoir offsets, suggests that use of the Cernica cemetery probably began in5355–5220 cal BC (95% probability)and ended in5190–5080 cal BC (28% probability)or5070–4940 (67% probability). The implications of this result are discussed, including with reference to other cemeteries of similar age in the region, the nature of social relations being projected through mortuary ritual, and the incorporation of older, Mesolithic, ways of doing things into Late Neolithic mortuary practice.

In the present paper we discuss a few issues regarding the secular variation (SV) and secular acceleration (SA) of the geomagnetic field that have consequences on mapping them at regional scales. Data from the European network of geomagnetic observatories have been analyzed from the perspective offered by existing long time series of annual means. The existence of high-frequency ingredients in the temporal change of the main field has been taken into account too. The importance of eliminating, from observatory and main field model data, prior to any discussion on secular variation, the signal related to external variations is demonstrated. Its consequences for SV analysis and/or mapping, including the jerk concept, are shown. Also, the importance of the geographical scale at which the SV is represented is discussed. To that aim, we used gufm1, IGRF and CM4 models for the main field from which the residual external signature was eliminated. The contribution of high-frequency ingredients to the map pattern is revealed. The results of the paper set additional observational constraints to the main field and geodynamo modeling.

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