Reflecting on PASUC Heritage Initiatives through Time, Positionality, and Place

This paper reports on heritage initiatives associated with a 12-year-long archaeology project in Yucatan, Mexico. Our work has involved both surprises and setbacks and in the spirit of adding to the repository of useful knowledge, we present these in a frank and transparent manner. Our findings are significant for a number of reasons. First, we show that the possibilities available to a heritage project facilitated by archaeologists depend not just on the form and focus of other stakeholders, but on the gender, sexuality, and class position of the archaeologists. Second, we provide a ground-level view of what approaches work well and which do not in terms of identifying aspects of cultural heritage that are relevant to a broad swath of stakeholders. Finally, we discuss ways in which heritage projects can overcome constraints to expanding community collaboration

Using multiple chronometers to establish a long, directly-dated lacustrine record:Constraining >600,000 years of environmental change at Chew Bahir, Ethiopia

Despite eastern Africa being a key location in the emergence of Homo sapiens and their subsequent dispersal out of Africa, there is a paucity of long, well-dated climate records in the region to contextualize this history. To address this issue, we dated a ∼293 m long composite sediment core from Chew Bahir, south Ethiopia, using three independent chronometers (radiocarbon, 40Ar/39Ar, and optically stimulated luminescence) combined with geochemical correlation to a known-age tephra. The site is located in a climatically sensitive region, and is close to Omo Kibish, the earliest documented Homo sapiens fossil site in eastern Africa, and to the proposed dispersal routes for H. sapiens out of Africa. The 30 ages generated by the various techniques are internally consistent, stratigraphically coherent, and span the full range of the core depth. A Bayesian age-depth model developed using these ages results in a chronology that forms one of the longest independently dated, high-resolution lacustrine sediment records from eastern Africa. The chronology illustrates that any record of environmental change preserved in the composite sediment core from Chew Bahir would span the entire timescale of modern human evolution and dispersal, encompassing the time period of the transition from Acheulean to Middle Stone Age (MSA), and subsequently to Later Stone Age (LSA) technology, making the core well-placed to address questions regarding environmental change and hominin evolutionary adaptation. The benefits to such studies of direct dating and the use of multiple independent chronometers are discussed. Highlights • Four independent dating methods applied to ∼293 m lake core from southern Ethiopia. • Reveals 620 ka high-resolution sedimentary record near key fossil hominin sites. • Mean accumulation rate of 0.47 mm/a comparable to other African lacustrine sediments. • Accumulation rate fell to 0.1 mm/a during MIS 2, likely due to reduced sediment supply. • Use of multiple independent chronometers is a powerful approach in lake settings

Hydroclimate changes in eastern Africa over the past 200,000 years may have influenced early human dispersal

Abstract: Reconstructions of climatic and environmental conditions can contribute to current debates about the factors that influenced early human dispersal within and beyond Africa. Here we analyse a 200,000-year multi-proxy paleoclimate record from Chew Bahir, a tectonic lake basin in the southern Ethiopian rift. Our record reveals two modes of climate change, both associated temporally and regionally with a specific type of human behavior. The first is a long-term trend towards greater aridity between 200,000 and 60,000 years ago, modulated by precession-driven wet-dry cycles. Here, more favorable wetter environmental conditions may have facilitated long-range human expansion into new territory, while less favorable dry periods may have led to spatial constriction and isolation of local human populations. The second mode of climate change observed since 60,000 years ago mimics millennial to centennial-scale Dansgaard-Oeschger cycles and Heinrich events. We hypothesize that human populations may have responded to these shorter climate fluctuations with local dispersal between montane and lowland habitats

Pleistocene climate variability in eastern Africa influenced hominin evolution

AbstractDespite more than half a century of hominin fossil discoveries in eastern Africa, the regional environmental context of hominin evolution and dispersal is not well established due to the lack of continuous palaeoenvironmental records from one of the proven habitats of early human populations, particularly for the Pleistocene epoch. Here we present a 620,000-year environmental record from Chew Bahir, southern Ethiopia, which is proximal to key fossil sites. Our record documents the potential influence of different episodes of climatic variability on hominin biological and cultural transformation. The appearance of high anatomical diversity in hominin groups coincides with long-lasting and relatively stable humid conditions from ~620,000 to 275,000 years bp (episodes 1–6), interrupted by several abrupt and extreme hydroclimate perturbations. A pattern of pronounced climatic cyclicity transformed habitats during episodes 7–9 (~275,000–60,000 years bp), a crucial phase encompassing the gradual transition from Acheulean to Middle Stone Age technologies, the emergence of Homo sapiens in eastern Africa and key human social and cultural innovations. Those accumulative innovations plus the alignment of humid pulses between northeastern Africa and the eastern Mediterranean during high-frequency climate oscillations of episodes 10–12 (~60,000–10,000 years bp) could have facilitated the global dispersal of H. sapiens.</jats:p

TRY plant trait database – enhanced coverage and open access

Plant traits - the morphological, anatomical, physiological, biochemical and phenological characteristics of plants - determine how plants respond to environmental factors, affect other trophic levels, and influence ecosystem properties and their benefits and detriments to people. Plant trait data thus represent the basis for a vast area of research spanning from evolutionary biology, community and functional ecology, to biodiversity conservation, ecosystem and landscape management, restoration, biogeography and earth system modelling. Since its foundation in 2007, the TRY database of plant traits has grown continuously. It now provides unprecedented data coverage under an open access data policy and is the main plant trait database used by the research community worldwide. Increasingly, the TRY database also supports new frontiers of trait‐based plant research, including the identification of data gaps and the subsequent mobilization or measurement of new data. To support this development, in this article we evaluate the extent of the trait data compiled in TRY and analyse emerging patterns of data coverage and representativeness. Best species coverage is achieved for categorical traits - almost complete coverage for ‘plant growth form’. However, most traits relevant for ecology and vegetation modelling are characterized by continuous intraspecific variation and trait–environmental relationships. These traits have to be measured on individual plants in their respective environment. Despite unprecedented data coverage, we observe a humbling lack of completeness and representativeness of these continuous traits in many aspects. We, therefore, conclude that reducing data gaps and biases in the TRY database remains a key challenge and requires a coordinated approach to data mobilization and trait measurements. This can only be achieved in collaboration with other initiatives

The genetic architecture of the human cerebral cortex

The cerebral cortex underlies our complex cognitive capabilities, yet little is known about the specific genetic loci that influence human cortical structure. To identify genetic variants that affect cortical structure, we conducted a genome-wide association meta-analysis of brain magnetic resonance imaging data from 51,665 individuals. We analyzed the surface area and average thickness of the whole cortex and 34 regions with known functional specializations. We identified 199 significant loci and found significant enrichment for loci influencing total surface area within regulatory elements that are active during prenatal cortical development, supporting the radial unit hypothesis. Loci that affect regional surface area cluster near genes in Wnt signaling pathways, which influence progenitor expansion and areal identity. Variation in cortical structure is genetically correlated with cognitive function, Parkinson's disease, insomnia, depression, neuroticism, and attention deficit hyperactivity disorder

SOCIAL DIFFERENTIATION AMONG RURAL MAYA HOUSEHOLDS IN CHUNHUAYUM, YUCATAN, MEXICO, DURING THE LATE PRECLASSIC THROUGH THE EARLY CLASSIC (300 B.C. – A.D. 600)

This dissertation addresses social differentiation among rural residents of Chunhuayum, an ancient Maya village in northwest Yucatan, from the Late Preclassic to the Late Early Classic (300 B.C. – A.D. 600/630). The three axes of social differentiation investigated are household wealth, occupation, and social connectivity to external networks. Using a practice theory approach, my research seeks to identify how material and social practices shaped and expressed social differentiation among Chunhuayum households, as well as how these may have shaped the particular history of Chunhuayum within its regional context. Throughout Chunhuayum’s occupation, residential architecture was the most salient marker of wealth disparities, although nuanced variation found among households’ possessions, including decorated and serving ware, obsidian, and shell, suggest households also differed in occupation, social connectivity, and local authority. I argue wealth inequalities emerged during the Preclassic, likely based on household size as larger labor pools could produce and transmit greater social and material resources to later generations. Chunhuayum’s Early Classic residents continued shaping locally meaningful differences through both habituated uses of everyday objects and innovative action. The greater resources accumulated by two households, N148 and N141, enabled them to engage in locally innovative strategies of socio-material wellbeing during the late Early Classic—shell crafting and group oriented ritual orchestration—that ultimately had different outcomes. N148 hosted village-wide, group oriented, rituals within their household compound starting in the Late Preclassic through the Early Classic. These rituals not only benefited the N148 household in establishing greater authority and wealth within the village, but also likely supported the community’s longevity by fostering inter-household obligations and a shared sense of place that would continue into the Postclassic. Crafters at N141 made disks out of conch shell using some of the large amounts of obsidian they procured, which they likely traded outside of Chunhuayum. N141’s more “open” livelihood strategy enabled this household to increase their social connectivity and portable wealth during the Early Classic, yet did not enable the household’s to maintain their wealth or social connectivity into the Late Classic. This dissertation adds to the growing literature underlining the rich and multifaceted lives of ancient rural populations and supports a number of points concerning ancient Maya rurality. Notwithstanding their shared commonalities, people were active and at times innovative in shaping social differences locally and beyond. While Chunhuayum lacks the archaeological proxies often associated with elite social identity, rural residents shaped locally intelligible differences through the materials, skills, ritual spaces, and social relations available to them. Moreover, following the disintegration of the Uc. polity during the Early Classic, residents actively engaged in increasingly complex relations within and beyond their village and strengthened local forms of authority, suggesting that local processes are inherent to rural complexity, which cannot be simply understood as a trickling-down of normative hierarchical structures. Finally, Chunhuayum presents an example of how most rural communities were neither wholly dependent nor fully isolated from larger centers but instead practiced a combination of open and closed-community strategies. The varied practices and relationships of rural residents, including strategies in facing new circumstances, led to diverging outcomes for both households and the community at large. Understanding how people distinguished themselves within a rural context challenges underlying cultural hierarchies concerning rural populations— embedded in archaeological research as they are in society writ-large—and highlights the nuanced ways a variety of people partake in social processes

Key words. Phosphatases, cdc25C, S-phase, Human Cells

International audienceIn view of the common regulatory mechanism that induces transcription of the mitotic phosphatase cdc25C and cyclin A at the beginning of S-phase, we investigated whether cdc25C was required for S-phase transit. Here, we show that in both nontransformed human fibroblasts and HeLa cells, cdc25C protein levels significantly increased concomitant with S-phase onset and cyclin A synthesis. Activity measurements on immunoprecipitates from synchronized HeLa cells revealed a sharp rise in cdc25C-associated phosphatase activity that coincided with S-phase. Microinjection of various antisense-cdc25C molecules led to inhibition of DNA synthesis in both HeLa cells and human fibroblasts. Furthermore, transfection of small interfering RNA directed against cdc25C specifically depleted cdc25C in HeLa cells without affecting cdc25A or cdc25B levels. Cdc25C RNA interference was also accompanied by S-phase inhibition. In cells depleted of cdc25C by antisense or siRNA, normal cell cycle progression could be re-established through microinjection of wild-type cdc25C protein but not inactive C377S mutant protein. Taken together, these results show that cdc25C not only plays a role at the G2/M transition but also in the modulation of DNA replication where its function is distinct from that of cdc25A

The addressing fragment of mitogaligin: first insights into functional and structural properties.

International audienceMitogaligin is a mitochondrion-targeting protein involved in cell death. The sequence of the protein is unrelated to that of any known pro- or antiapoptotic protein. Mitochondrial targeting is controlled by an internal sequence from residues 31 to 53, and although this sequence is essential and sufficient to provoke cell death, the precise mechanism of action at the mitochondrial membrane remains to be elucidated. Here, by focusing on the [31-53] fragment, we first assessed and confirmed its cell cytotoxicity by microinjection. Subsequently, with the aid of membrane models, we evaluated the impact of the membrane environment on the 3D structure of the peptide and on how the peptide is embedded and oriented within membranes. The fragment is well organized, even though it does not contain a canonical secondary structure, and adopts an interfacial location. Structural comparison with other membrane-interacting Trp-rich peptides demonstrated similarities with the antimicrobial peptide tritrpcidin