6 research outputs found

    Lateglacial–Holocene environments and human occupation in the Upper Lena region of Eastern Siberia derived from sedimentary and zooarchaeological data from Lake Ochaul

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    In the current study, different geochemical and biological proxies, including pollen, non-pollen palynomorphs, ostracods and molluscs, from an AMS radiocarbon-dated sediment core from Lake Ochaul (54°14′N, 106°28′E; 641 m a.s.l.) are presented and discussed. Ochaul is a fresh-water lake and an archaeological site situated ca. 100 km northwest of Lake Baikal in the upper reaches of the Lena River. The 260-cm-long sedimentary record presented here spans the Lateglacial–Holocene interval, between ca. 13,500 cal yr BP and the present. The reconstructions of the postglacial vegetation and lake system development are discussed along with the regional climate dynamics and the hemispheric-scale environmental changes. During the Allerød interstadial the region around Lake Ochaul was dominated by sparse taiga forests. Cooling during the Younger Dryas led to a more open tundra landscape where trees formed patchy forest stands in climatically favourable environments. This facilitated a rapid spread of forests at the onset of the Early Holocene during which the study region was probably characterized by seasonally dry climate controlled by the interplay of higher insolation, lower global sea levels and remaining ice sheets in the North Atlantic region. After thermal and moisture optimum conditions and a maximum spread of forests during the Middle Holocene, continuous cooling and a trend to more open forests landscapes marked the Late Holocene. These long-term trends were interrupted by several relatively short episodes of change in the vegetation and algal records, which coincide with short-term (centennial-scale) Northern Hemisphere cooling/drying phases. This shows that the regional vegetation reacted sensitively to these climate oscillations. Six AMS radiocarbon dates of bone material of large herbivorous animals from the Ochaul archaeological site located at the northern shore of the lake provide important information about prehistoric hunter-gatherers and indicate that activities at the site took place at ca. 27,780–27,160 cal yr BP (95% probability range) as well as during the Mesolithic (ca. 8850–8450 cal yr BP), Early, Middle and Late Neolithic (between ca. 6840 and 5490 cal yr BP) and the Iron Age (ca. 2120–1930 cal yr BP). Our results demonstrate that despite major environmental transformations following the Last Glacial Maximum, Lake Ochaul and the Malaya Anga River valley remained attractive for large herbivores and for prehistoric hunter-gatherers, even during the Middle Neolithic cultural “hiatus” (ca. 6660–6060 cal yr BP) in Cis-Baikal, as documented by the published archaeological records

    Lateglacial–Holocene environments and human occupation in the Upper Lena region of Eastern Siberia derived from sedimentary and zooarchaeological data from Lake Ochaul

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    In the current study, different geochemical and biological proxies, including pollen, non-pollen palynomorphs, ostracods and molluscs, from an AMS radiocarbon-dated sediment core from Lake Ochaul (54°14′N, 106°28′E; 641 m a.s.l.) are presented and discussed. Ochaul is a fresh-water lake and an archaeological site situated ca. 100 km northwest of Lake Baikal in the upper reaches of the Lena River. The 260-cm-long sedimentary record presented here spans the Lateglacial–Holocene interval, between ca. 13,500 cal yr BP and the present. The reconstructions of the postglacial vegetation and lake system development are discussed along with the regional climate dynamics and the hemispheric-scale environmental changes. During the Allerød interstadial the region around Lake Ochaul was dominated by sparse taiga forests. Cooling during the Younger Dryas led to a more open tundra landscape where trees formed patchy forest stands in climatically favourable environments. This facilitated a rapid spread of forests at the onset of the Early Holocene during which the study region was probably characterized by seasonally dry climate controlled by the interplay of higher insolation, lower global sea levels and remaining ice sheets in the North Atlantic region. After thermal and moisture optimum conditions and a maximum spread of forests during the Middle Holocene, continuous cooling and a trend to more open forests landscapes marked the Late Holocene. These long-term trends were interrupted by several relatively short episodes of change in the vegetation and algal records, which coincide with short-term (centennial-scale) Northern Hemisphere cooling/drying phases. This shows that the regional vegetation reacted sensitively to these climate oscillations. Six AMS radiocarbon dates of bone material of large herbivorous animals from the Ochaul archaeological site located at the northern shore of the lake provide important information about prehistoric hunter-gatherers and indicate that activities at the site took place at ca. 27,780–27,160 cal yr BP (95% probability range) as well as during the Mesolithic (ca. 8850–8450 cal yr BP), Early, Middle and Late Neolithic (between ca. 6840 and 5490 cal yr BP) and the Iron Age (ca. 2120–1930 cal yr BP). Our results demonstrate that despite major environmental transformations following the Last Glacial Maximum, Lake Ochaul and the Malaya Anga River valley remained attractive for large herbivores and for prehistoric hunter-gatherers, even during the Middle Neolithic cultural “hiatus” (ca. 6660–6060 cal yr BP) in Cis-Baikal, as documented by the published archaeological records

    High-resolution pollen record of the last 13,500 years derived from AMS radiocarbon dated sediments of Lake Ochaul in Cis-Baikal (Eastern Siberia)

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    A 260-cm-long section of a sediment core from Lake Ochaul (54°14'N, 106°28'E; 641 m a.s.l.), a freshwater lake in the Cis-Baikal region, ca. 100 km northwest of Lake Baikal, was analysed for pollen and non-pollen palynomorphs. This high-resolution AMS-dated record covers the Lateglacial and Holocene interval between ca. 13,500 cal yr BP and the present. A total of 84 samples from the Och18-II-1 and Och18-II-2 sections have been treated using dense media separation to extract pollen and non-pollen palynomorphs (e.g. fern and moss spores, Chironomidae remains, Botryococcus and Pediastrum green algae colonies) for further microscopic analysis

    Nutritional Sensor REDD1 in Cancer and Inflammation: Friend or Foe?

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    Regulated in Development and DNA Damage Response 1 (REDD1)/DNA Damage-Induced Transcript 4 (DDIT4) is an immediate early response gene activated by different stress conditions, including growth factor depletion, hypoxia, DNA damage, and stress hormones, i.e., glucocorticoids. The most known functions of REDD1 are the inhibition of proliferative signaling and the regulation of metabolism via the repression of the central regulator of these processes, the mammalian target of rapamycin (mTOR). The involvement of REDD1 in cell growth, apoptosis, metabolism, and oxidative stress implies its role in various pathological conditions, including cancer and inflammatory diseases. Recently, REDD1 was identified as one of the central genes mechanistically involved in undesirable atrophic effects induced by chronic topical and systemic glucocorticoids widely used for the treatment of blood cancer and inflammatory diseases. In this review, we discuss the role of REDD1 in the regulation of cell signaling and processes in normal and cancer cells, its involvement in the pathogenesis of different diseases, and the approach to safer glucocorticoid receptor (GR)-targeted therapies via a combination of glucocorticoids and REDD1 inhibitors to decrease the adverse atrophogenic effects of these steroids
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