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"Measuring instruments History"
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The earliest human occupation of the high-altitude Tibetan Plateau 40 thousand to 30 thousand years ago
Human colonization of the high-altitude Tibetan Plateau has generally been thought to have been confined to the past few thousand years of the Holocene. Zhang et al. report an investigation of the Nwya Devu archaeological site in central Tibet, 4600 meters above sea level, with Paleolithic occupation dates of ∼40 thousand to 30 thousand years ago (see the Perspective by Zhang and Dennell). The site has yielded a range of stone tools, indicating the adaptive ability of early modern humans to the harsh environment of the “roof of the world.” The findings also suggest that people from Tibet and Siberia may have interacted at this time. Science , this issue p. 1049 ; see also p. 992 The Nwya Devu Paleolithic site in Tibet, 4600 meters above sea level, preserves evidence of early human high-altitude adaptation. The Tibetan Plateau is the highest and one of the most demanding environments ever inhabited by humans. We investigated the timing and mechanisms of its initial colonization at the Nwya Devu site, located nearly 4600 meters above sea level. This site, dating from 40,000 to 30,000 years ago, is the highest Paleolithic archaeological site yet identified globally. Nwya Devu has yielded an abundant blade tool assemblage, indicating hitherto-unknown capacities for the survival of modern humans who camped in this environment. This site deepens the history of the peopling of the “roof of the world” and the antiquity of human high-altitude occupations more generally.
Journal Article
Future Directions for Incorporating Intersectionality Into Quantitative Population Health Research
Intersectionality, an analytical approach rooted in Black feminist theory and praxis, has become more widely used in population health research. The majority of quantitative population health studies have used intersectionality as a theoretical framework to investigate how multiple social identities rather than social inequalities simultaneously influence health inequities. Although a few researchers have developed methods to assess how multiple forms of interpersonal discrimination shape the health of multiply marginalized groups and others have called for the use of multilevel modeling to examine the role of intersecting dimensions of structural discrimination, critical qualitative, multidisciplinary, and community-based participatory research approaches are needed to more fully incorporate the core ideas of intersectionality—including social inequality, relationality, complexity, power, social context, and social justice—into quantitative population health research studies or programs. By more comprehensively capturing and addressing the influence of intersecting structural factors, social and historical processes, and systems of power and oppression on the health of multiply marginalized individuals, quantitative population health researchers will more fully leverage intersectionality’s transformational power and move one step closer to achieving social justice and health equity.
Journal Article
Age estimates for hominin fossils and the onset of the Upper Palaeolithic at Denisova Cave
Denisova Cave in the Siberian Altai (Russia) is a key site for understanding the complex relationships between hominin groups that inhabited Eurasia in the Middle and Late Pleistocene epoch. DNA sequenced from human remains found at this site has revealed the presence of a hitherto unknown hominin group, the Denisovans
1
,
2
, and high-coverage genomes from both Neanderthal and Denisovan fossils provide evidence for admixture between these two populations
3
. Determining the age of these fossils is important if we are to understand the nature of hominin interaction, and aspects of their cultural and subsistence adaptations. Here we present 50 radiocarbon determinations from the late Middle and Upper Palaeolithic layers of the site. We also report three direct dates for hominin fragments and obtain a mitochondrial DNA sequence for one of them. We apply a Bayesian age modelling approach that combines chronometric (radiocarbon, uranium series and optical ages), stratigraphic and genetic data to calculate probabilistically the age of the human fossils at the site. Our modelled estimate for the age of the oldest Denisovan fossil suggests that this group was present at the site as early as 195,000 years ago (at 95.4% probability). All Neanderthal fossils—as well as Denisova 11, the daughter of a Neanderthal and a Denisovan
4
—date to between 80,000 and 140,000 years ago. The youngest Denisovan dates to 52,000–76,000 years ago. Direct radiocarbon dating of Upper Palaeolithic tooth pendants and bone points yielded the earliest evidence for the production of these artefacts in northern Eurasia, between 43,000 and 49,000 calibrated years before present (taken as
ad
1950). On the basis of current archaeological evidence, it may be assumed that these artefacts are associated with the Denisovan population. It is not currently possible to determine whether anatomically modern humans were involved in their production, as modern-human fossil and genetic evidence of such antiquity has not yet been identified in the Altai region.
Bayesian modelling of chronometric, stratigraphic and genetic data from Denisova Cave provides a chronological framework for understanding Neanderthal and Denisovan presence at the site, as well as interactions between these groups.
Journal Article
The timing and effect of the earliest human arrivals in North America
The peopling of the Americas marks a major expansion of humans across the planet. However, questions regarding the timing and mechanisms of this dispersal remain, and the previously accepted model (termed ‘Clovis-first’)—suggesting that the first inhabitants of the Americas were linked with the Clovis tradition, a complex marked by distinctive fluted lithic points
1
—has been effectively refuted. Here we analyse chronometric data from 42 North American and Beringian archaeological sites using a Bayesian age modelling approach, and use the resulting chronological framework to elucidate spatiotemporal patterns of human dispersal. We then integrate these patterns with the available genetic and climatic evidence. The data obtained show that humans were probably present before, during and immediately after the Last Glacial Maximum (about 26.5–19 thousand years ago)
2
,
3
but that more widespread occupation began during a period of abrupt warming, Greenland Interstadial 1 (about 14.7–12.9 thousand years before
ad
2000)
4
. We also identify the near-synchronous commencement of Beringian, Clovis and Western Stemmed cultural traditions, and an overlap of each with the last dates for the appearance of 18 now-extinct faunal genera. Our analysis suggests that the widespread expansion of humans through North America was a key factor in the extinction of large terrestrial mammals.
A Bayesian age model suggests that human dispersal to the Americas probably began before the Last Glacial Maximum, overlapping with the last dates of appearance for several faunal genera.
Journal Article
Temple occupation and the tempo of collapse at Angkor Wat, Cambodia
The 9th–15th century Angkorian state was Southeast Asia’s greatest premodern empire and Angkor Wat in the World Heritage site of Angkor is one of its largest religious monuments. Here we use excavation and chronometric data from three field seasons at Angkor Wat to understand the decline and reorganization of the Angkorian Empire, which was a more protracted and complex process than historians imagined. Excavation data and Bayesian modeling on a corpus of 16 radiocarbon dates in particular demand a revised chronology for the Angkor Wat landscape. It was initially in use from the 11th century CE with subsequent habitation until the 13th century CE. Following this period, there is a gap in our dates, which we hypothesize signifies a change in the use of the occupation mounds during this period. However, Angkor Wat was never completely abandoned, as the dates suggest that the mounds were in use again in the late 14th–early 15th centuries until the 17th or 18th centuries CE. This break in dates points toward a reorganization of Angkor Wat’s enclosure space, but not during the historically recorded 15th century collapse. Our excavation data are consistent with multiple lines of evidence demonstrating the region’s continued ideological importance and residential use, even after the collapse and shift southward of the polity’s capital. We argue that fine-grained chronological analysis is critical to building local historical sequences and illustrate how such granularity adds nuance to how we interpret the tempo of organizational change before, during, and after the decline of Angkor.
Journal Article
Unifying Perspectives: All-encompassing Reality vs. All-inclusive Physics
This article 1 presents a two-part proposal aimed at exploring “reality” through unifying perspectives and universally consistent foundations. Both parts are inspired by Erwin Schrödinger’s principle of objectivation, particularly the function of the ‘Subject of Cognizance’ embedded within it, and the (seemingly unresolvable, yet inescapable!) issue of the ‘location’ of the boundary between the ‘observed’ and the ‘observer’ that arises in the interpretation of quantum theory. In the first part, it is argued that different interpretations of quantum theory could be viewed as complementary rather than as alternatives, for each interpretation provides insight into different aspects of reality, and thus, integrating perspectives from multiple quantum interpretations can offer a more holistic understanding of reality than relying on a single interpretation. The plausibility of this argument is explained with a brief reference to the phenomenon of electron double-slit interference. The second part of the proposal asserts that, it is essential to eliminate any discrepancy between the way in which the terms ‘physics’ and ‘reality’ are regarded in scientific inquiry, for developing a universal, all-encompassing and consistent world view of the latter — emphasising that not only the ‘observed’ but also the ‘observer’ (considered here as the measuring instrument or apparatus) and the ‘Subject of Cognizance’ (viewed here as the conscious observer) are integral parts of the whole reality. This assertion is supported by some specific remarks of Richard Feynman and David Bohm.
Journal Article
Climate influence on the early human occupation of South America during the late Pleistocene
The settlement of South America marks one of the final steps in human expansion. This study examines the impact of climate change on this process, focusing on two millennial-scale climatic phases—the Antarctic Cold Reversal and Younger Dryas. Using Bayesian chronological modelling, a cultural timeline was constructed from approximately 150 archaeological sites and 1700 dates, and compared against paleoclimatic records. Findings suggested that human activity likely began in regions most affected by the Antarctic Cold Reversal, specifically in southernmost and high-altitude areas. Together with estimates indicating that the onset of megafaunal exploitation and bifacial point technology occurred before or during the Antarctic Cold Reversal, results suggested that cold conditions did not likely hinder human settlement. Key factors likely included accumulated cultural adaptation and relatively milder climatic changes in the Southern Hemisphere. More widespread occupation likely occurred during or, more likely, after the Younger Dryas as conditions stabilised. Results highlighted the western Andes as a crucial dispersal route and questioned the role of humans and climatic shifts on megafaunal extinctions. An analysis of the compiled archaeo-chronometric dataset revealed significant underrepresentation and reporting gaps, highlighting the need for expanded research and rigorous documentation to improve the reliability of the cultural timeline.
Here, the author presents a Bayesian chronological model based in 1700 radiocarbon dates that traces human occupation South America in the late Pleistocene and describes the potential impact of climate changes on occupation patterns.
Journal Article
Chronometric data and stratigraphic evidence support discontinuity between Neanderthals and early Homo sapiens in the Italian Peninsula
The process by which Palaeolithic Europe was transformed from a Neanderthal-dominated region to one occupied exclusively by
Homo sapiens
has proven challenging to diagnose. A blurred chronology has made it difficult to determine when Neanderthals disappeared and whether modern humans overlapped with them. Italy is a crucial region because here we can identify not only Late Mousterian industries, assumed to be associated with Neanderthals, but also early Upper Palaeolithic industries linked with the appearance of early
H. sapiens
, such as the Uluzzian and the Aurignacian. Here, we present a chronometric dataset of 105 new determinations (74 radiocarbon and 31 luminescence ages) from four key southern Italian sites: Cavallo, Castelcivita, Cala, and Oscurusciuto. We built Bayesian-based chronometric models incorporating these results alongside the relative stratigraphic sequences at each site. The results suggest; 1) that the disappearance of Neanderthals probably pre-dated the appearance of early modern humans in the region and; 2) that there was a partial overlap in the chronology of the Uluzzian and Protoaurignacian, suggesting that these industries may have been produced by different human groups in Europe.
Here, the authors present 74 radiocarbon and 31 luminescence age determinations from four sites in southern Italy. They use these data to suggest that Neanderthal disappearance in the region predated the appearance of early modern humans, a previously unclear chronology
Journal Article
Ice stream subglacial access for ice-sheet history and fast ice flow: the BEAMISH Project on Rutford Ice Stream, West Antarctica and initial results on basal conditions
Three holes were drilled to the bed of Rutford Ice Stream, through ice up to 2154 m thick, to investigate the basal processes and conditions associated with fast ice flow and the glacial history of the West Antarctic Ice Sheet. A narrative of the drilling, measuring and sampling activities, as well as some preliminary results and initial interpretations of subglacial conditions, is given. These were the deepest subglacial access holes ever drilled using the hot-water drilling method. Samples of bed and englacial sediments were recovered, and a number of instruments were installed in the ice column and the bed. The ice–bed interface was found to be unfrozen, with an existing, well-developed subglacial hydrological system at high pressure, within ~1% of the ice overburden. The bed itself comprises soft, water-saturated sediments, consistent with previous geophysical interpretations. Englacial sediment quantity varies significantly between two locations ~2 km apart, and possibly over even shorter (~20 m) distances. Difficulties and unusual observations encountered while connecting to the subglacial hydrological system in one hole possibly resulted from the presence of a large clast embedded in the bottom of the ice.
Journal Article