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Denisovans are members of a hominin group who are currently only known directly from fragmentary fossils, the genomes of which have been studied from a single site, Denisova Cave 1 – 3 in Siberia. They are also known indirectly from their genetic legacy through gene flow into several low-altitude East Asian populations 4 , 5 and high-altitude modern Tibetans 6 . The lack of morphologically informative Denisovan fossils hinders our ability to connect geographically and temporally dispersed fossil hominins from Asia and to understand in a coherent manner their relation to recent Asian populations. This includes understanding the genetic adaptation of humans to the high-altitude Tibetan Plateau 7 , 8 , which was inherited from the Denisovans. Here we report a Denisovan mandible, identified by ancient protein analysis 9 , 10 , found on the Tibetan Plateau in Baishiya Karst Cave, Xiahe, Gansu, China. We determine the mandible to be at least 160 thousand years old through U-series dating of an adhering carbonate matrix. The Xiahe specimen provides direct evidence of the Denisovans outside the Altai Mountains and its analysis unique insights into Denisovan mandibular and dental morphology. Our results indicate that archaic hominins occupied the Tibetan Plateau in the Middle Pleistocene epoch and successfully adapted to high-altitude hypoxic environments long before the regional arrival of modern Homo sapiens . Fossil evidence indicates that Denisovans occupied the Tibetan Plateau in the Middle Pleistocene epoch and successfully adapted to this high-altitude hypoxic environments long before the regional arrival of modern Homo sapiens .

The study of prehistoric hunter-gatherer subsistence strategies on the Tibetan Plateau is important for understanding the mechanisms and processes of human adaption to high altitude environments. But to date, only a few Paleolithic sites have been found on the Tibetan Plateau with clear stratigraphy and reliable dating. These sites are mainly distributed in the Qinghai Lake Basin on the northeastern part of the plateau, and the sporadic fauna and flora remains excavated provide limited information about the subsistence strategies of hunter-gatherers. In 2014, relatively abundant animal remains were unearthed in the Lower Cultural Layer (LCL, 15400–13100 cal yr BP) of the “151 site” located in the Qinghai Lake Basin, providing important information about human subsistence strategies on the Tibetan Plateau during the Last Deglaciation. Zooarchaeological analysis of these faunal remains indicates that hunter-gatherers at the “151 site” mainly targeted large ungulates of Bos and wild horse/ass, and only brought back the most nutritious parts of animal carcasses including upper and intermediate limb bones, heads, and trunks (ribs and vertebrae). People then processed and consumed the carcasses around single hearths. Our comprehensive analyses of contemporaneous sites in the Qinghai Lake Basin show that a subsistence strategy involving opportunistic hunting of ungulates, high mobility, and short occupation of campsites was used by terminal Pleistocene hunter-gatherers to adapt to the high-altitude environment on the Tibetan Plateau. This subsistence strategy may have been a first step of gradual hunter-gatherer adaptation to the extreme conditions on the Tibetan Plateau after the Last Glacial Maximum, and laid the foundation for the widespread distribution of hunter-gatherers on the plateau during the Holocene.

Prehistoric human history on the Tibetan Plateau is a hotly debated topic. Archaeological research on the plateau during the past few decades has enormously improved our understanding of the topic and makes it possible for us to consider the processes and mechanisms of prehistoric human migration to the region. By reviewing the published archaeological research on the Tibetan Plateau, we propose that the first people on the plateau initially spread into the He-Huang region from the Chinese Loess Plateau, and then moved to the low elevation Northeastern Tibetan Plateau and perhaps subsequently to the entire plateau. This process consisted of four stages. （1） During the climatic amelioration of the Last Deglacial period （15-11.6 ka BP）, Upper Paleolithic hunter-gatherers with a developed microlithic technology first spread into the Northeastern Tibetan Plateau. （2） In the early-mid Holocene （11.6-6 ka BP）, Epipaleolithic microlithic hunter-gatherers were widely distributed on the northeastern plateau and spread southwards to the interior plateau, possibly with millet agriculture developed in the neigh- boring low elevation regions. （3） In the mid-late Holocene （6-4 ka BP）, Neolithic millet farmers spread into low elevation river valleys in the northeastern and southeastern plateau areas. （4） In the late Holocene （4-2.3 ka BP）, Bronze Age barley and wheat farmers further settled on the high elevation regions of the Tibetan Plateau, especially after 3.6 ka BP. Finally, we sug- gest that all of the reported Paleolithic sites earlier than the LGM on the Tibetan Plateau need further examination.

The excited states of polyatomic systems are rather complex, and often exhibit meta-stable dynamical behaviors. Static analysis of reaction pathway often fails to sufficiently characterize excited state motions due to their highly non-equilibrium nature. Here, we proposed a time series guided clustering algorithm to generate most relevant meta-stable patterns directly from ab initio dynamic trajectories. Based on the knowledge of these meta-stable patterns, we suggested an interpolation scheme with only a concrete and finite set of known patterns to accurately predict the ground and excited state properties of the entire dynamics trajectories, namely, the prediction with ensemble models (PEM). As illustrated with the example of sinapic acids, The PEM method does not require any training data beyond the clustering algorithm, and the estimation error for both ground and excited state is very close, which indicates one could predict the ground and excited state molecular properties with similar accuracy. These results may provide us some insights to construct molecular mechanism models with compatible energy terms as traditional force fields.

Climatic change that affects biological productivity is often argued to be a primary force influencing human activities during the glacial period. To test this assumption, we combine in-site pollen, paleoclimatic, and archaeological data from the Dadiwan site and nearby areas on the western Loess Plateau (WLP) that date to Marine Oxygen Isotope Stage (MIS) 3. Our comparison of multiple datasets suggests that regional human activities increased when the vegetation around the Dadiwan area shifted from forest steppe in the early MIS 3 (59–46.7 ka) to steppe in the middle to late MIS 3 (46.7–29.5 ka). Our results indicate that regional human activities increased again during the late MIS 3 when the amount of precipitation was higher, as indicated by the lower Artemisia proportion. We suggest that increased precipitation on the WLP enhanced the above-ground biomass production and may be responsible for an increase in human activity and population in this region.

While N,N′ -dialkylimidazolium ionic liquids (ILs) have been well-established as effective solvents for dissolution and processing of cellulose, the detailed mechanism at the molecular level still remains unclear. In this work, we present a combined quantum chemistry and molecular dynamics simulation study on how the ILs dissolve cellulose. On the basis of calculations on 1-butyl-3-methylimidazolium chloride, one of the most effective ILs dissolving cellulose, we further studied the molecular behavior of cellulose models (i.e. cellulose oligomers with degrees of polymerization n  = 2, 4, and 6) in the IL, including the structural features and hydrogen bonding patterns. The collected data indicate that both chloride anions and imidazolium cations of the IL interact with the oligomer via hydrogen bonds. However, the anions occupy the first coordination shell of the oligomer, and the strength and number of hydrogen bonds and the interaction energy between anions and the oligomer are much larger than those between cations and the oligomer. It is observed that the intramolecular hydrogen bond in the oligomer is broken under the combined effect of anions and cations. The present results emphasize that the chloride anions play a critically important role and the imidazolium cations also present a remarkable contribution in the cellulose dissolution. This point of view is different from previous one that only underlines the importance of the chloride anions in the cellulose dissolution. The present results improve our understanding for the cellulose dissolution in imidazolium chloride ILs.

Hot holes in Pt‐Cu alloy clusters can act as catalyst to accelerate the intrinsic aerobic oxidation reactions. It is described that under visible light irradiation the synergistic alcohol catalytic oxidation on Pt‐Cu alloy clusters (≈1.1 nm)/TiO2 nanobelts could be significant promoted by interband‐excitation‐generated long‐lifetime hot holes in the clusters.

The accurate radiocarbon dating of loess-soil sequences plays an essential role in the reconstruction of the environmental and climatic changes in continental settings during the last glaciation and Holocene. However, our knowledge about the reliability of radiocarbon ages of various fractions of soil and loess samples is still insufficient. Here, we present our study results on radio- carbon ages based on bulk organic matter, humin fraction, and carbonate of samples collected from a loess-paleosol section in the western Chinese Loess Plateau. We compare these observations with the optically stimulated luminescence ages and charcoal radiocarbon ages to evaluate the reliability of these fractions. We observed that the radio- carbon ages of humin fraction are very close to those of charcoal and are consistent with the optically stimulated luminescence ages within the experimental errors. We observed a significant deviation in the radiocarbon ages of carbonate and bulk organic matter from those of charcoal and optically stimulated luminescence ages, likely due to the dilution of these fractions during the pedogenetic process. Our results reveal that, except for charcoal, the humin fraction may yield reliable laC ages for the Chinese loess-soil sequence.

Intensive research on China's Western Loess Plateau has located 63 Palaeolithic deposits, which together allow the authors to present a general model of hominin occupation from 80 000 to 18 000 years ago. Tools, subsistence and settlement correlate nicely with the climate: the warm wet MIS3 seeing expansion and more organised acquisition of quartz, and the Late Glacial Maximum that followed, a reduction in human presence but possibly an increase in ingenuity.