1,721,317 research outputs found
A combined method for DNA analysis and radiocarbon dating from a single sample
Full text linkCurrent protocols for ancient DNA and radiocarbon analysis of ancient bones and teeth call for multiple destructive samplings of a given specimen, thereby increasing the extent of undesirable damage to precious archaeological material. Here we present a method that makes it possible to obtain both ancient DNA sequences and radiocarbon dates from the same sample material. This is achieved by releasing DNA from the bone matrix through incubation with either EDTA or phosphate buffer prior to complete demineralization and collagen extraction utilizing the acid-base-acid-gelatinization and ultrafiltration procedure established in most radiocarbon dating laboratories. Using a set of 12 bones of different ages and preservation conditions we demonstrate that on average 89% of the DNA can be released from sample powder with minimal, or 38% without any, detectable collagen loss. We also detect no skews in radiocarbon dates compared to untreated samples. Given the different material demands for radiocarbon dating (500 mg of bone/dentine) and DNA analysis (10–100 mg), combined DNA and collagen extraction not only streamlines the sampling process but also drastically increases the amount of DNA that can be recovered from limited sample material
Extension of the Swiss Lateglacial tree-ring chronologies
No full textFossil wood finds reveal a high resolution paleoclimatic proxy record of Lateglacial and Early Holocene. Eighty-one
buried fossil pine stumps have been excavated on the construction site (Gaenziloo) of the A4-highway tunnel through
Uetliberg near Zurich (Switzerland). The trees were buried during their lifetime by loamy alluvia washed down from
the upper part of the slopes. The stumps have remained well preserved for more than 13,500 years. The cross sections
of the trunks were analyzed dendrochronologically. The sections were dated by 14C, and 14C age vs. ring number were
obtained from decadal sample segments.
Three floating chronologies were built. They cover a time span of 428 years in the Mid-Allerød (GAEALLCH_A),
561 years in the Late-Allerød (GAEALLCH_D) and 212 years in the Younger Dryas (GAEYD_A). Visual
synchronization, t-values, percentages of parallel variation (‘Gleichlaeufigkeit’) and radiocarbon wiggle matching
(14C age determinations on a decadal scale) as well as a check by the program Cofecha support the validity of the
resulting chronologies.
The two Allerød-chronologies from Gaenziloo were linked with two chronologies from Daettnau (DAEALCH_1
and DAEALCH_2) published by Kaiser, K.F. (1993. Beitra ̈ ge zur Klimageschichte vom Hochglazial bis ins fru ̈ he
Holoza ̈ n, rekonstruiert mit Jahrringen und Molluskenschalen aus verschiedenen Vereisungsgebieten. Ziegler Druck-
und Verlags-AG, Winterthur. 206pp). They extend the existing floating Swiss chronology in the Late-Allerød by a total
of 186 years. Unfortunately independent chronology GAEYD_A does not overlap with the actual absolute chronology
developed by the tree-ring laboratory of the University of Hohenheim (Friedrich, M. et al., 2004. The 12,460 year
Hohenheim oak and pine tree-ring chronology from Central Europe – A unique annual record for radiocarbon
calibration and paleo-environment reconstructions. Radiocarbon 46(3), 1111–22.)
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Exploring different methods of cellulose extraction for 14C dating
Full text linkIn this study we aim to identify the optimal cellulose extraction protocol for 14C dating of wood, with a focus on glacial trees. To achieve this, we compare three cellulose extraction methods on the basis of cellulose yield and 14C age. The study is conducted on 12 wood samples of different species, in varying states of preservation with ages covering the full 14C age range. Cellulose is extracted from each sample following three different protocols selected from the literature: ABA-B, BABAB and 2Chlorox. The extracted cellulose was graphitised and dated with the MICADAS (Mini Carbon Dating System) at the ETH AMS laboratory. Although all three methods are considered efficient, the BABAB protocol, despite being a more aggressive procedure, allows the extraction of a sufficient amount of cellulose to be 14C dated and leads to the most reliable results, particularly for very old and background samples (samples with 14C content of zero)
Palaeoenvironments during the period of the Neanderthals settlement in Chagyrskaya cave (Altai Mountains, Russia)
Full text link© 2015 Elsevier B.V.The Altai Mountains, situated in the middle of Asia, have been inhabited by human groups since prehistoric times. Many Middle Palaeolithic sites (open-air sites and caves) are located in the northwestern part of the Altai Mountains. The uniqueness of this area is in the simultaneous habitation of different human species, such as Neanderthals, Sapiens and Denisovians. The material culture of the Altai Middle Palaeolithic is mostly homogeneous; however, two caves are distinguished from other sites—Okladnikov Cave and the recently studied Chagyrskaya Cave, located in the Charysh River valley. Palaeolithic assemblages from both caves are comparable with the Mousterian industries recorded in certain regions of Eurasia and represent a special variant of the Altai Middle Palaeolithic industries, known as the Sibiryachikha facies. Anthropological data from these caves suggest that the Sibiryachikha variant was associated with Neanderthals. In this study, we reconstruct the palaeoenvironmental conditions of the period of the Neanderthals settlement in the northwestern part of the Altai Mountains based on bioproxies, such as pollen records and large mammal remains. The time of the Neanderthals settlement of Chagyrskaya Cave is attributed to the termination of MIS4 and is characterised by an arid and continental climate. Dry steppe communities were widespread in the Charysh River valley. It is possible that the Chagyrskaya Cave represents a long-term hunting camp where butchering and processing of game animals were carried out. In the following warmer and more humid period the Neanderthals left the cave. This was around the same time when anatomically modern humans began appearing in Western Siberia
Back to the future: The advantage of studying key events in human evolution using a new high resolution radiocarbon method
Full text linkRadiocarbon dating is the most widely applied dating method in archaeology, especially in human evolution studies, where it is used to determine the chronology of key events, such as the replacement of Neanderthals by modern humans in Europe. However, the method does not always provide precise and accurate enough ages to understand the important processes of human evolution. Here we review the newest method developments in radiocarbon dating (‘Radiocarbon 3.0’), which can lead us to much better chronologies and understanding of the major events in recent human evolution. As an example, we apply these new methods to discuss the dating of the important Palaeolithic site of Bacho Kiro (Bulgaria)
Mutamenti e persistenze nei rituali funerari eneolitici in Emilia-Romagna: studio antropologico e ricerca archeologica a confronto
No full textDirect dating confirms the presence of otter and badger in early Holocene Ireland
No full textThe origin of Ireland’s fauna is an unresolved issue in the history of the island. Although researchers once considered Ireland’s mammals to have spread to Ireland during the early postglacial from 11,700 cal BP, research has increasingly suggested humans translocated many of these species to Ireland. However, due to sparse evidence, the origin of Ireland’s purported native mustelid species remains unanswered. In this study, we shed light on the history of otter and badger in Ireland by directly dating suspected early examples of these species from Derragh, Co. Longford, a late Mesolithic campsite. The results demonstrate that both of these species have been present in Ireland for at least 7000–8000 years. It is not clear if they represent self-colonisers or Mesolithic anthropogenic translocations. Although these finds do not rule out local extinction and later reintroduction, they show that we can no longer assume they are solely late Holocene introductions
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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