Intensive chemical weathering in the Arctic during the Miocene Climatic Optimum

The Arctic today has shallow, chemically immature, and frost-dominated weathering regimes. At Sokli, Finland (68°N), a 70 m deep palaeo-weathering profile is developed in a Devonian carbonatite pipe that represents fundamentally different past weathering environments. Formation of the apatite-francolite P-ore likely began under Palaeogene warm, humid climates. Later, cryptomelane (K-Mn oxide) crusts developed within the ore that have yielded peak 40Ar/39Ar ages of 16.20 ± 0.13 Ma (2σ)., The crusts formed at the redox front during the Miocene Climatic Optimum (∼16.9–14.7 Ma) under mean annual temperatures ∼12–14 °C warmer than today. The presence of the cryptomelane crust at shallow depth (15 m) indicates very low erosion rates since formation, consistent with its position on a tectonically stable Archaean craton and in the cold-based ice-divide zone of successive Fennoscandian ice sheets. The Miocene Climatic Optimum triggered a pulse of intensive weathering in mid- and low latitudes; the Sokli cryptomelane ages demonstrate that intensive chemical weathering extended into the Arctic.</p

Angkor Borei and Protohistoric Trade Networks: A View from the Glass and Stone Bead Assemblage

40 pages. Published by University of Hawai'i Press: Carter, A.K., Dussubieux, L., Stark, M.T., & Gilg, H.A. (2021). Angkor Borei and Protohistoric Trade Networks: A View from the Glass and Stone Bead Assemblage. Asian Perspectives 60(1), 32-70. doi:10.1353/asi.2020.0036.Angkor Borei, Cambodia was an important urban center related to the early first millennium C.E. polity known as Funan. Excavations in the protohistoric period Vat Komnou Cemetery site uncovered over 1300 glass and stone beads, which are important material indicators of trade. In this article, we review data from earlier studies and add new previously unpublished data on glass and stone beads from this collection as well as previously unpublished glass compositional analyses from the nearby site of Oc Eo, Vietnam. Examinations of the glass beads highlight the presence of large quantities of high alumina mineral soda glass associated with Sri Lankan or South Indian bead production as well as smaller quantities of other glass types in circulation throughout Southeast Asia. Compositional and morphological studies of agate/carnelian beads show strong affinities with the Indian bead industry, while the garnet beads came from raw material sources in southern India. Overall, Angkor Borei's bead collection shows strong contacts with different regions of South Asia. Comparison with the bead assemblages of other contemporaneous sites demonstrate strong affinities with sites farther inland, such as Phum Snay and Prei Khmeng, Cambodia and Ban Non Wat, Thailand rather than other maritime coastal sites in Southeast Asia. We argue that the stone and glass beads at Angkor Borei are related to intensified interaction with South Asia and that elites at Angkor Borei used these exotic prestige goods to build alliances with sites farther inland forming an intraregional exchange network we call the Mekong Interaction Sphere.The authors wish to thank the Ministry of Culture and Fine Arts in Cambodia which facilitated the study of the beads from Angkor Borei. Thanks also to Seth Quintus for discussion of Bayesian modeling of the Vat Komnou cemetery dates and Mike Shand for assistance with Figure 2. Thanks to Pierre-Yves Manguin for providing materials from Oc Eo and information on his work at this site. Carter's research was funded by the Henry Luce Foundation/ACLS Grants in East and Southeast Asian Archaeology and Early History Dissertation Fellowship, The Bead Society of Los Angeles, The Portland Bead Society, The Bead Study Trust, Graduate Women in Science–Beta Chapter, and the Geological Society of America. SEM was undertaken at the University of Wisconsin Department of Animal Sciences Microscopy Laboratories and the University of Oregon CAMCOR laboratory

Intensive chemical weathering in the Arctic during the Miocene Climatic Optimum

The Arctic today has shallow, chemically immature, and frost-dominated weathering regimes. At Sokli, Finland (68°N), a 70 m deep palaeo-weathering profile is developed in a Devonian carbonatite pipe that represents fundamentally different past weathering environments. Formation of the apatite-francolite P-ore likely began under Palaeogene warm, humid climates. Later, cryptomelane (K-Mn oxide) crusts developed within the ore that have yielded peak 40Ar/39Ar ages of 16.20 ± 0.13 Ma (2σ)., The crusts formed at the redox front during the Miocene Climatic Optimum (∼16.9–14.7 Ma) under mean annual temperatures ∼12–14 °C warmer than today. The presence of the cryptomelane crust at shallow depth (15 m) indicates very low erosion rates since formation, consistent with its position on a tectonically stable Archaean craton and in the cold-based ice-divide zone of successive Fennoscandian ice sheets. The Miocene Climatic Optimum triggered a pulse of intensive weathering in mid- and low latitudes; the Sokli cryptomelane ages demonstrate that intensive chemical weathering extended into the Arctic

The influence of water on the strength of Neapolitan Yellow Tuff, the most widely used building stone in Naples (Italy)

International audienc

COVID-19 symptoms at hospital admission vary with age and sex: results from the ISARIC prospective multinational observational study

Background: The ISARIC prospective multinational observational study is the largest cohort of hospitalized patients with COVID-19. We present relationships of age, sex, and nationality to presenting symptoms. Methods: International, prospective observational study of 60 109 hospitalized symptomatic patients with laboratory-confirmed COVID-19 recruited from 43 countries between 30 January and 3 August 2020. Logistic regression was performed to evaluate relationships of age and sex to published COVID-19 case definitions and the most commonly reported symptoms. Results: ‘Typical’ symptoms of fever (69%), cough (68%) and shortness of breath (66%) were the most commonly reported. 92% of patients experienced at least one of these. Prevalence of typical symptoms was greatest in 30- to 60-year-olds (respectively 80, 79, 69%; at least one 95%). They were reported less frequently in children (≤ 18 years: 69, 48, 23; 85%), older adults (≥ 70 years: 61, 62, 65; 90%), and women (66, 66, 64; 90%; vs. men 71, 70, 67; 93%, each P &lt; 0.001). The most common atypical presentations under 60 years of age were nausea and vomiting and abdominal pain, and over 60 years was confusion. Regression models showed significant differences in symptoms with sex, age and country. Interpretation: This international collaboration has allowed us to report reliable symptom data from the largest cohort of patients admitted to hospital with COVID-19. Adults over 60 and children admitted to hospital with COVID-19 are less likely to present with typical symptoms. Nausea and vomiting are common atypical presentations under 30 years. Confusion is a frequent atypical presentation of COVID-19 in adults over 60 years. Women are less likely to experience typical symptoms than men

Determinants of axial osmotic gradients in the differentiating countercurrent system

The renal medullary countercurrent system differentiates into its final segmental nephron function and geometry during perinatal development. The influence of these changes on the medullary longitudinal osmotic gradient cannot be evaluated by experimental studies. Therefore, a computation analysis using a differential equation model of the renal countercurrent system was applied to quantitate the effect of medullary architecture and solute transport on the concentration profiles for salt and urea in tubules (loop of Henle and collecting duct) and in the central core along the entire medulla during ontogeny. The results indicate that both the changing distribution of loop segments within the medulla and the increase in active salt transport of the individual thick ascending loop determine the magnitude and slope of the axial medullary solute gradients. </jats:p