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Aims: The 11-year solar cycle (Schwabe cycle) is the dominant pattern of solar magnetic activity reflecting the oscillatory dynamo mechanism in the Sun’s convection zone. Solar cycles have been directly observed since 1700, while indirect proxy data suggest their existence over a much longer period of time, but generally without resolving individual cycles and their continuity. Here we reconstruct individual solar cycles for the last millennium using recently obtained ¹⁴C data and state-of-the-art models. Methods: Starting with the ¹⁴C production rate determined from the so far most precise measurements of radiocarbon content in tree rings, solar activity was reconstructed in the following three physics-based steps: (1) correction of the ¹⁴C production rate for the changing geomagnetic field; (2) computation of the open solar magnetic flux; and (3) conversion into sunspot numbers outside of grand minima. All known uncertainties, including both measurement and model uncertainties, were straightforwardly accounted for by a Monte-Carlo method. Results: Cyclic solar activity is reconstructed for the period 971–1900 (85 individual cycles) along with its uncertainties. This more than doubles the number of solar cycles known from direct solar observations. We found that the lengths and strengths of well-defined cycles outside grand minima are consistent with those obtained from the direct sunspot observations after 1750. The validity of the Waldmeier rule (cycles with fast-rising phase tend to be stronger) is confirmed at a highly significant level. Solar activity is found to be in a deep grand minimum when the activity is mostly below the sunspot formation threshold for about 250 years. Therefore, although considerable cyclic variability in ¹⁴C is seen even during grand minima, individual solar cycles can hardly be reliably resolved therein. Three potential solar particle events, ca. 994, 1052, and 1279 AD, are shown to occur around the maximum phases of solar cycles. Conclusions: A new approximately 1000-year-long solar activity reconstruction, in the form of annual (pseudo) sunspot numbers with the full assessment of all known uncertainties, is presented based on new high-precision Δ¹⁴C measurements and state-of-the-art models, more than doubling the number of individually resolved solar cycles. This forms a solid basis for new, more detailed studies of solar variability.

The new radiocarbon calibration curve (IntCal20) allows us to calculate the gradient of the relationship between 14C age and calendar age over the past 55 millennia before the present (55 ka BP). The new gradient curve exhibits a prolonged and prominent maximum between 48 and 40 ka BP during which the radiocarbon clock runs almost twice as fast as it should. This radiocarbon time dilation is due to the increase in the atmospheric 14C/12C ratio caused by the 14C production rise linked to the transition into the Laschamp geomagnetic excursion centered around 41 ka BP. The major maximum in the gradient from 48 to 40 ka BP is a new feature of the IntCal20 calibration curve, with far-reaching impacts for scientific communities, such as prehistory and paleoclimatology, relying on accurate ages in this time range. To illustrate, we consider the duration of the overlap between Neanderthals and Homo sapiens in Eurasia.

The concentration of radiocarbon (14C) differs between ocean and atmosphere. Radiocarbon determinations from samples which obtained their 14C in the marine environment therefore need a marine-specific calibration curve and cannot be calibrated directly against the atmospheric-based IntCal20 curve. This paper presents Marine20, an update to the internationally agreed marine radiocarbon age calibration curve that provides a non-polar global-average marine record of radiocarbon from 0–55 cal kBP and serves as a baseline for regional oceanic variation. Marine20 is intended for calibration of marine radiocarbon samples from non-polar regions; it is not suitable for calibration in polar regions where variability in sea ice extent, ocean upwelling and air-sea gas exchange may have caused larger changes to concentrations of marine radiocarbon. The Marine20 curve is based upon 500 simulations with an ocean/atmosphere/biosphere box-model of the global carbon cycle that has been forced by posterior realizations of our Northern Hemispheric atmospheric IntCal20 14C curve and reconstructed changes in CO2 obtained from ice core data. These forcings enable us to incorporate carbon cycle dynamics and temporal changes in the atmospheric 14C level. The box-model simulations of the global-average marine radiocarbon reservoir age are similar to those of a more complex three-dimensional ocean general circulation model. However, simplicity and speed of the box model allow us to use a Monte Carlo approach to rigorously propagate the uncertainty in both the historic concentration of atmospheric 14C and other key parameters of the carbon cycle through to our final Marine20 calibration curve. This robust propagation of uncertainty is fundamental to providing reliable precision for the radiocarbon age calibration of marine based samples. We make a first step towards deconvolving the contributions of different processes to the total uncertainty; discuss the main differences of Marine20 from the previous age calibration curve Marine13; and identify the limitations of our approach together with key areas for further work. The updated values for ΔR, the regional marine radiocarbon reservoir age corrections required to calibrate against Marine20, can be found at the data base http://calib.org/marine/.

Imprecise chronology has entailed a fuzzy kind of prehistory. Prehistorians should no longer be content with timeframes that employ successive units of 200 years or more duration, or with slow change over the long term as their dominant chronological and interpretative perspective. The means to get away from very generalised accounts of the past is formal chronological modelling in a Bayesian framework. The Bayesian approach in general is outlined, with emphasis on its interpretive and iterative nature. The approach combines calibrated radiocarbon dates with knowledge of the archaeological contexts from which they are derived to produce a series of formal, probabilistic date estimates. Stringent demands are made of both the radiocarbon dates and our archaeological understanding of stratigraphy, associations, sample taphonomy and context in general. The Bayesian process at Alsónyék involved assessment of existing dates, careful definition of aims and objectives, the construction of a rigorous sampling strategy, with an explicit hierarchy of suitable samples, precise understanding of the contexts from which samples are derived, and simulation to achieve cost-effective use of resources. The principal material dated at Alsónyék was human and animal bone. Potential age offsets from non-vegetarian diets are carefully considered; ‘perfect pairs’ of human and animal bone samples from the same contexts indicate that human bone samples are not subject to wide-scale freshwater reservoir effects. Dietary inputs are estimated formally using a series of Bayesian mixing models. The sequence of iterative sampling submissions between 2012 and 2015 is described, and the procedures of the five laboratories involved are detailed. Procedures for model construction, validation and comparison are discussed. Finally, we consider how we can use precise timings to reveal the web of connections and successions that made up past lives, adding plot and context to a more precise chronicle to create narratives for peopling the past., Bericht der Römisch-Germanischen Kommission, Bd. 94. 2013 (2016): Bericht der Römisch-Germanischen Kommission

Combining atmospheric ∂14CO2 data sets from different networks or laboratories requires secure knowledge on their compatibility. In the present study, we compare ∂14CO2 results from the Heidelberg low-level counting (LLC) laboratory to 12 international accelerator mass spectrometry (AMS) laboratories using distributed aliquots of five pure CO2 samples. The averaged result of the LLC laboratory has a measurement bias of –0.3±0.5‰ with respect to the consensus value of the AMS laboratories for the investigated atmospheric ∂14C range of 9.6 to 40.4‰. Thus, the LLC measurements on average are not significantly different from the AMS laboratories, and the most likely measurement bias is smaller than the World Meteorological Organization (WMO) interlaboratory compatibility goal for ∂14CO2 of 0.5‰. The number of intercomparison samples was, however, too small to determine whether the measurement biases of the individual AMS laboratories fulfilled the WMO goal.

The excavations at Alsónyék revealed numerous Starčevo features, over 50 in the southern part of subsite 10B and some 500 in subsite 5603. The overwhelming majority of the features uncovered were individual pits and pit complexes. Traces of houses or above-ground structures were recorded, but no certain house plans could be identified; numerous hearths and ovens were found. 25 Starčevo burials have been identified, with some in disused pits and ovens. The occupation excavated in subsite 5603 was substantial, the largest yet discovered in Transdanubia. The north-west distribution of the Early Neolithic cultural complex of the northern Balkans – the Starčevo, Körös and Criş cultures – represents the first food-producing communities in many parts of the Carpathian basin. Starčevo sites are now known in the southern part of western Hungary up to Lake Balaton, but there are many unresolved questions about the precise chronology of the Early Neolithic in Transdanubia and beyond, in the Starčevo-Körös-Criş complex as a whole, and about the character and identity of the first farmers of the region. This paper presents 34 radiocarbon dates from 33 samples, interpreted within a Bayesian framework, for the dating of the Starčevo occupation at Alsónyék. 18 samples of human and animal bone were selected as part of the OTKA-funded project Alsónyék: from the beginnings of food production to the end of the Neolithic in collaboration with the ERC- funded The Times of Their Lives project, in conjunction with 15 existing dates from human burials. The programme aimed to date Starčevo occupation and burials at Alsónyék, and in so doing to contribute to further understanding of the character and pace of the spread of the Neolithic way of life in the region. The Bayesian model presented estimates that Starčevo activity probably began in 5775–5740 cal BC (68% probability), probably lasted for 190–245 years (68% probability), and probably ended in 5560–5525 cal BC (68% probability). The transition from pottery Style group 1 to 2 probably occurred in 5760–5730 cal BC (68% probability), with the transition from pottery Style group 2 to 3 probably in 5595–5570 cal BC (68% probability).The implications of these estimates for the character of the Starčevo occupation at Alsónyék are discussed, as well as for the wider development of the Starčevo culture and of the Early Neolithic in the region as a whole. The current picture suggests the densest Starčevo presence in south-east Transdanubia within the Hungarian distribution of the culture, with a gradual spread to the north later on. The results also demonstrate that Early Neolithic settlements in western Hungary lasted for a substantial period of time, across several human generations., Bericht der Römisch-Germanischen Kommission, Bd. 94. 2013 (2016): Bericht der Römisch-Germanischen Kommission

The Greenland Stadial 1 (GS-1; ~12.9 to 11.65 kyr cal BP) was a period of North Atlantic cooling, thought to have been initiated by North America fresh water runoff that caused a sustained reduction of North Atlantic Meridional Overturning Circulation (AMOC), resulting in an antiphase temperature response between the hemispheres (the 'bipolar seesaw'). Here we exploit sub-fossil New Zealand kauri trees to report the first securely dated, decadally-resolved atmospheric radiocarbon ((14)C) record spanning GS-1. By precisely aligning Southern and Northern Hemisphere tree-ring (14)C records with marine (14)C sequences we document two relatively short periods of AMOC collapse during the stadial, at ~12,920-12,640 cal BP and 12,050-11,900 cal BP. In addition, our data show that the interhemispheric atmospheric (14)C offset was close to zero prior to GS-1, before reaching 'near-modern' values at ~12,660 cal BP, consistent with synchronous recovery of overturning in both hemispheres and increased Southern Ocean ventilation. Hence, sustained North Atlantic cooling across GS-1 was not driven by a prolonged AMOC reduction but probably due to an equatorward migration of the Polar Front, reducing the advection of southwesterly air masses to high latitudes. Our findings suggest opposing hemispheric temperature trends were driven by atmospheric teleconnections, rather than AMOC changes.

This paper presents formally modelled date estimates,within a Bayesian chronological frame-work, for the sequence of deposits and material at the great Neolithic tell of Vinca-Belo Brdo near Belgrade, Serbia, on the basis of the first excavations, led by Miloje Vasic (1908-1934). This is part of a three-strand approach to dating the occupation and finds from the tell that is being undertaken as part of The Times of Their Lives project. A total of 85 radiocarbon measurements are now available from known depths through the Vasic sequence at Vinca. A Bayesian chronological model is constructed, using a poisson-process depositional model.

A 7-year-long data set of integrated high-precision 14CO(2) observations combined with occasional hourly 14CO(2) flask data from the Heidelberg sampling site is presented. Heidelberg is located in the highly populated and industrialized upper Rhine valley in southwestern Germany. The 14CO(2) data are used in combination with hourly carbon monoxide (CO) observations to estimate regional hourly fossil fuel CO2 (delta FFCO2) mixing ratios. We investigate three different 14C calibration schemes to calculate delta FFCO2: (1) the long-term median delta CO/delta FFCO2 ratio of 14.6 ppb ppm-1 (mean: 15.5 +/- 5.6 ppb ppm-1), (2) individual (2-)week-long integrated delta CO/delta FFCO2 ratios, which take into account the large week-to-week variability of +/- 5.6 ppb ppm-1 (1 Sigma; interquartile range: 5.5 ppb ppm-1), and (3) a calibration which also includes diurnal changes of the delta CO/delta FFCO2 ratio. We show that in winter a diurnally changing delta CO/delta FFCO2 ratio provides a much better agreement with the direct 14C-based hourly delta FFCO2 estimates whereas summer values are not significantly improved with a diurnal calibration. Using integrated 14CO(2) samples to determine weekly mean delta CO/delta FFCO2 ratios introduces a bias in the CO-based delta FFCO2 estimates which can be corrected for with diurnal grab sample data. Altogether our 14C-calibrated CO-based method allows determining delta FFCO2 at a semi-polluted site with a precision of approximately +/- 25%.

Muscheler et al.1 claim that the solar activity affecting cosmic rays was much higher in the past than we deduced2 from 14C measurements. However, this claim is based on a problematic normalization and is in conflict with independent results, such as the 44Ti activity in meteorites and the 10Be concentration in ice cores.

The radiocarbon calibration curve ImCal04 extends back to 26 cal kyr BP. While several high-resolution records exist beyond this limit, these data sets exhibit discrepancies of up, to several millennia. As a result, no calibration curve for the time range 26-50 cal kyr BP can be recommended as yet, but in this paper the IntCal04 working group compares the available data sets and offers a discussion of the information that they hold.

The first meeting of the IntCal04 working group took place at Queen's University Belfast from April 15 to 17, 2002. The participants are listed as co-authors of this report. The meeting considered criteria for the acceptance of data into the next official calibration dataset, the importance of including reliable estimates of uncertainty in both the radiocarbon ages and the cal ages, and potential methods for combining datasets. This preliminary report summarizes the criteria that were discussed, but does not yet give specific recommendations for inclusion or exclusion of individual datasets.

Type-2 autoimmune hepatitis is a subgroup of chronic hepatitis characterized by the presence of liver/kidney microsomal autoantibodies type 1 (LKM-1). A frequent association with chronic hepatitis C suggests that hepatitis virus might trigger autoimmune reactivity. LKM-1-positive chronic hepatitis is not uncommon in southern Europe but is rarely seen in the USA and the UK. The prevalence in Scandinavia is hitherto unknown.We used an automated prototype LKM-1 immunometry-based assay (IMx) to detect LKM-1 antibodies in sera from 350 Swedish patients with chronic liver diseases (100 with primary biliary cirrhosis, 80 with primary sclerosing cholangitis, 100 with hepatitis C, and 70 patients with various forms of chronic hepatitis, including 36 autoimmune cases), and from 17 children with autoimmune hepatitis. Sera reactive in the IMx assay were subjected to immunofluorescence testing.No clearly LKM-reactive sera were detected. Serum samples from 29 patients were borderline reactive in the IMx assay but tested negative in the confirmatory immunofluorescence test. Positive tests in the former assay were likely caused by reactivity against microsomal antigens other than LKM-1/cytochrome P450IID6.LKM-1-positive type-2 autoimmune hepatitis is very rare in Sweden. Furthermore, chronic hepatitis C did not trigger this type of autoimmune reactivity in our patients, probably owing to genetic insusceptibility.