CLUSTERING OF CALIBRATED RADIOCARBON DATES: SITE-SPECIFIC CHRONOLOGICAL SEQUENCES IDENTIFIED BY DENSE RADIOCARBON SAMPLING

Radiocarbon ◽  
2020 ◽  
pp. 1-10
Author(s):  
Peter Demján ◽  
Peter Pavúk

ABSTRACT Calibrated radiocarbon (14C) determinations are commonly used in archaeology to assign calendar dates to a site’s chronological phases identified based on additional evidence such as stratigraphy. In the absence of such evidence, we can perform dense 14C sampling of the site to attempt to identify periods of heightened activity, separated by periods of inactivity, which correspond to archaeological phases and gaps between them. We propose a method to achieve this by hierarchical cluster analysis of the calibrated 14C dates, followed by testing of the different clustering solutions for consistency based on silhouette coefficient and statistical significance using randomization. Separate events identified in such a way can then be regarded as evidence for distinct phases of activity and used to construct a site-specific sequence. This can be in turn used as a Bayesian prior to further narrow down the distributions of the calibrated 14C dates. We assessed the validity of the method using simulated data as well as real-life archaeological data from the Bronze Age settlement of Troy. A Python implementation of the method is available online at https://github.com/demjanp/clustering_14C.

Radiocarbon ◽  
2011 ◽  
Vol 53 (1) ◽  
pp. 21-37 ◽  
Author(s):  
Y Maniatis ◽  
S Papadopoulos

The transitional period known as the Final Neolithic-Early Bronze Age in Greece, falling in terms of absolute dates within the 4th millennium BC, is an obscure and enigmatic period. Few sites in northern Greece or the southern Balkans have produced evidence of 4th millennium BC occupation, and the sites that do are mainly concentrated in the last third of the 4th millennium toward the beginning of the EBA. This paper presents archaeological evidence and radiocarbon dates from a site that covers part of the gap, Aghios Ioannis on Thassos, the northernmost Aegean island. It is a coastal site of seasonal occupation and most probably depended on organized animal husbandry plus hunting and fishing activities. From the first excavations in 1996, there was evidence that the site was occupied during the Final Neolithic to the beginning of the Early Bronze Age. The 14C dates obtained fall towards the end of the 4th millennium if not closer to the middle. The presence of human activity in this last part of the 4th millennium “gap” on Thassos is by itself an interesting discovery that enlarges our knowledge for this obscure period and is of environmental and cultural significance.


2008 ◽  
Vol 1 (2) ◽  
pp. 125-138
Author(s):  
CLARE HOLLOWELL

This paper examines girls and power in British co-educational boarding school stories published from 1928 to 1958. While feminist scholars have hailed the girls’ school story as a site of potential resistance to constricting gender roles, the same can not be said of the co-educational school story. While the genres share many tropes and characterisation, the move from an all-female world to a co-educational setting allows the characters access to a narrower range of gender roles, and renders the female characters significantly less powerful. The disciplinary structures of the co-educational schools, mirroring those in real life, operate in a supposedly progressive manner that in fact removes girls from access to power.


1998 ◽  
Vol 21 (1) ◽  
pp. 1-28
Author(s):  
John A Atkinson ◽  
Camilla Dickson ◽  
Jane Downes ◽  
Paul Robins ◽  
David Sanderson

Summary Two small burnt mounds were excavated as part of the programme to mitigate the impact of motorway construction in the Crawford area. The excavations followed a research strategy designed to address questions of date and function. This paper surveys the various competing theories about burnt mounds and how the archaeological evidence was evaluated against those theories. Both sites produced radiocarbon dates from the Bronze Age and evidence to suggest that they were cooking places. In addition, a short account is presented of two further burnt mounds discovered during the construction of the motorway in Annandale.


Radiocarbon ◽  
2015 ◽  
Vol 57 (5) ◽  
pp. 807-823 ◽  
Author(s):  
Yannis Maniatis ◽  
Nerantzis Nerantzis ◽  
Stratis Papadopoulos

Radiocarbon dates obtained for the coastal hilltop settlement of Aghios Antonios Potos in south Thasos are statistically treated to define the absolute chronology for the start and the end of the various habitation and cultural phases at the site. The location was first occupied during the Final Neolithic (FN) between 3800 and 3600 BC, extending this much contested phase to the lowest up to now record for Thasos and the northern Greece. The site is continuously inhabited from Early Bronze Age I until the early Late Bronze Age (LBA; 1363 BC) when it was abandoned. Comparison with other sites in Thasos and particularly with the inland site of Kastri Theologos showed that the first occupation at Aghios Antonios came soon after the abandonment of Kastri in the beginning of the 4th millennium. In fact, after the decline and abandonment of Aghios Antonios in the LBA, the site of Kastri was reinhabited, leading to the hypothesis that part of the coastal population moved inland. The presumed chronological sequence of alternate habitation between the two settlements may evoke explanations for sociocultural and/or environmental dynamics behind population movements in prehistoric Thasos. A major conclusion of the project is that the 4th millennium occupation gap attested in many sites of Greece, especially in the north, is probably bridged in south Thasos, when the data from all sites are taken together. The mobility of people in Final Neolithic south Thasos may explain the general phenomenon of limited occupational sequences in the FN of north Greece.


1989 ◽  
Vol 9 (4) ◽  
pp. 1507-1512 ◽  
Author(s):  
H Zhu ◽  
H Conrad-Webb ◽  
X S Liao ◽  
P S Perlman ◽  
R A Butow

All mRNAs of yeast mitochondria are processed at their 3' ends within a conserved dodecamer sequence, 5'-AAUAAUAUUCUU-3'. A dominant nuclear suppressor, SUV3-I, was previously isolated because it suppresses a dodecamer deletion at the 3' end of the var1 gene. We have tested the effects of SUV3-1 on a mutant containing two adjacent transversions within a dodecamer at the 3' end of fit1, a gene located within the 1,143-base-pair intron of the 21S rRNA gene, whose product is a site-specific endonuclease required in crosses for the quantitative transmission of that intron to 21S alleles that lack it. The fit1 dodecamer mutations blocked both intron transmission and dodecamer cleavage, neither of which was suppressed by SUV3-1 when present in heterozygous or homozygous configurations. Unexpectedly, we found that SUV3-1 completely blocked cleavage of the wild-type fit1 dodecamer and, in SUV3-1 homozygous crosses, intron conversion. In addition, SUV3-1 resulted in at least a 40-fold increase in the amount of excised intron accumulated. Genetic analysis showed that these phenotypes resulted from the same mutation. We conclude that cleavage of a wild-type dodecamer sequence at the 3' end of the fit1 gene is essential for fit1 expression.


2007 ◽  
Vol 14 (1) ◽  
pp. 79-88 ◽  
Author(s):  
D. V. Divine ◽  
F. Godtliebsen

Abstract. This study proposes and justifies a Bayesian approach to modeling wavelet coefficients and finding statistically significant features in wavelet power spectra. The approach utilizes ideas elaborated in scale-space smoothing methods and wavelet data analysis. We treat each scale of the discrete wavelet decomposition as a sequence of independent random variables and then apply Bayes' rule for constructing the posterior distribution of the smoothed wavelet coefficients. Samples drawn from the posterior are subsequently used for finding the estimate of the true wavelet spectrum at each scale. The method offers two different significance testing procedures for wavelet spectra. A traditional approach assesses the statistical significance against a red noise background. The second procedure tests for homoscedasticity of the wavelet power assessing whether the spectrum derivative significantly differs from zero at each particular point of the spectrum. Case studies with simulated data and climatic time-series prove the method to be a potentially useful tool in data analysis.


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