692 research outputs found

    Returning Methods of Rykyu\u27s Drifting Ships in the Qing Dynasty

    Get PDF
    The communication between Ryukyu・Okinawa and China has a long history. It has been said that the history has begun even at Ming Dynasty. Ryukyu Dynasty were canonized by Chinese king even after Satsuma clan (now Kagoshima Prefecture)\u27s invasion in the beginning of 17 century. The tributary relations between Ryukyu and China had last for 5 centuries until Ryukyu became Okinawa Prefecture by Meiji Japanese government in 1872. The relationship between China and Ryukyu basic were tributary relations. However, the main transportation mean in Ryukyu were by ship, and lots of ship encountered typhoon, lost control of their ship, and finally were drifted to China continent. You can refer to these historical documentation in the book 「Selected documentation of China-Ryukyu relations in Qing Dynasty」 which was public by China First Historical Archives. Lots of ship-drift cases are written in this book from Qianlong era to Guangxu era of Qing Dynasty. Various forms of transportation can be found form those cases. This paper will not focus on tributary ships from Ryukyu, but on the part of rescue and aid from Qing government to those who were drifted from Ryukyu

    Refining 14C dating of bone >30,000 BP : establishing an accurate chronology for the Middle to Upper Palaeolithic transition in France

    Get PDF
    his thesis aims to improve the chronology of the transition from the Middle to Upper Palaeolithic in France through the radiocarbon dating of bone collagen samples. This requires accurate calibration of the radiocarbon time scale for this time interval, reliable extraction of collagen from prehistoric bones and accurate AMS radiocarbon dating. The recent developments in radiocarbon calibration beyond 26,000 cal BP, which have resulted in the formulation of an internationally agreed calibration curve spanning back to 50,000 cal BP, are discussed in the introductory section of this thesis. The methodological section of this thesis presents the results of experiments undertaken to establish an optimal procedure for extracting collagen from bone samples for radiocarbon dating. The main objectives of these experiments were to remove contamination from the organic bone fractions, which generally results in younger ages, and to avoid the incorporation of exogenous carbon in the laboratory through careful cleaning of the equipment. In order to achieve these aims, a suite of bone pretreatment methods were adopted and the resulting collagen extracts were sent for dating to different laboratories. The radiocarbon ages obtained from two test bones cover large ranges, which fall significantly beyond measurement error. This may be due to differences in both pretreatment methods and in the set-ups of different AMS facilities. The research undertaken for the present thesis has allowed the author to establish a protocol of laboratory procedures that produces consistent ages for bone collagen older than 30,000 cal BP This protocol was implemented at the Max Planck Institute for Evolutionary Anthropology (MPI-EVA) and, in chapter 7 of the thesis, it is adopted to establish a chronological framework for the site of Les Cottés in France. This site has an almost uninterrupted sequence spanning from the Middle to the Upper Palaeolithic, including Mousterian, Châtelperronian and Aurignacian occupations. The AMS radiocarbon determinations obtained from bone collagen samples, pretreated according to the quality criteria developed in this thesis, accurately date not only the different human cultures which succeeded each other at Les Cottés, but also the climatic episodes and oscillations which characterized the Middle to Upper Palaeolithic transition. This case study demonstrates that AMS radiocarbon dating of mammal bone collagen can be reliably used for establishing the chronology of sites older than 30,000 14C years BP and with well-preserved deposits.FdA – Publicaties niet-programma gebonde

    Exploring different methods of cellulose extraction for 14C dating

    Get PDF
    In this study we aim to identify the optimal cellulose extraction protocol for 14C dating of wood, with a focus on glacial trees. To achieve this, we compare three cellulose extraction methods on the basis of cellulose yield and 14C age. The study is conducted on 12 wood samples of different species, in varying states of preservation with ages covering the full 14C age range. Cellulose is extracted from each sample following three different protocols selected from the literature: ABA-B, BABAB and 2Chlorox. The extracted cellulose was graphitised and dated with the MICADAS (Mini Carbon Dating System) at the ETH AMS laboratory. Although all three methods are considered efficient, the BABAB protocol, despite being a more aggressive procedure, allows the extraction of a sufficient amount of cellulose to be 14C dated and leads to the most reliable results, particularly for very old and background samples (samples with 14C content of zero)

    The molecular chaperone Hsp90 is a component of the cap-binding complex and interacts with the translational repressor Cup during Drosophila oogenesis

    Get PDF
    In metazoa, the spatio-temporal translation of diverse mRNAs is essential to guarantee proper oocyte maturation and early embryogenesis. The eukaryotic translation initiation factor 4E (eIF4E), which binds the 5′ cap structure of eukaryotic mRNAs, associates with either stimulatory or inhibitory factors to modulate protein synthesis. In order to identify novel factors that might act at the translational level during Drosophila oogenesis, we have undertaken a functional proteomic approach and isolated the product of the Hsp83 gene, the evolutionarily conserved chaperone Hsp90, as a specific component of the cap-binding complex. Here we report that Hsp90 interacts in vitro with the translational repressor Cup. In addition, we show that Hsp83 and cup interact genetically, since lowering Hsp90 activity enhances the oogenesis alterations linked to diverse cup mutant alleles. Hsp90 and Cup co-localize in the cytoplasm of the developing germ-line cells within the germarium, thus suggesting a common function from the earliest stages of oogenesis. Taken together, our data start elucidating the role of Hsp90 during Drosophila female germ-line development and strengthen the idea that Cup has multiple essential functions during egg chamber development

    Algorithms for the on-line travelling salesman

    Get PDF
    In this paper the problem of efficiently serving a sequence of requests presented in an on-line fashion located at points of a metric space is considered. We call this problem the On-Line Travelling Salesman Problem (OLTSP). It has a variety of relevant applications in logistics and robotics. We consider two versions of the problem. In the first one the server is not required to return to the departure point after all presented requests have been served. For this problem we derive a lower bound on the competitive ratio of 2 on the real line. Besides, a 2.5-competitive algorithm for a wide class of metric spaces, and a 7/3-competitive algorithm for the real line are provided. For the other version of the problem, in which returning to the departure point is required, we present an optimal 2-competitive algorithm for the above mentioned general class of metric spaces. If in this case the metric space is the real line we present a 1.75-competitive algorithm that compares with a \approx 1.64 lower bound

    Recent developments in calibration for archaeological and environmental samples

    Get PDF
    The curves recommended for calibrating radiocarbon (14C) dates into absolute dates have been updated. For calibrating atmospheric samples from the Northern Hemisphere, the new curve is called IntCal20. This is accompanied by associated curves SHCal20 for the Southern Hemisphere, and Marine20 for marine samples. In this “companion article” we discuss advances and developments that have led to improvements in the updated curves and highlight some issues of relevance for the general readership. In particular the dendrochronological based part of the curve has seen a significant increase in data, with single-year resolution for certain time ranges, extending back to 13,910 calBP. Beyond the tree rings, the new curve is based upon an updated combination of marine corals, speleothems, macrofossils, and varved sediments and now reaches back to 55,000 calBP. Alongside these data advances, we have developed a new, bespoke statistical curve construction methodology to allow better incorporation of the diverse constituent records and produce a more robust curve with uncertainties. Combined, these data and methodological advances offer the potential for significant new insight into our past. We discuss some implications for the user, such as the dating of the Santorini eruption and also some consequences of the new curve for Paleolithic archaeology

    The Quaternary lions of Ukraine and a trend of decreasing size in Panthera spelaea (advance online)

    Get PDF
    The fossil record of the cave lion, Panthera spelaea, suggests a gradual decrease in body size, the process peaking just before the extinction of the species at the end of the Late Pleistocene. Such an evolutionary trend appears rather unusual for a large felid species and requires further investigation. This study reviews the cave lions of Ukraine, whose fossils are known from 46 localities dated from 800 kyr to 18–17 kyr ago, with a special emphasis on size changes through time. We describe several important finds including those of Panthera spelaea fossilis from Sambir, Panthera spelaea ssp. from Bilykh Stin Cave and Panthera spelaea spelaea from Kryshtaleva Cave. We make subspecific identifications of specimens from the region and focus on their size characteristics. Our analysis of Ukrainian cave lions agrees with the temporal trend of decreasing size, particularly accelerating during MIS 2, as exemplified by the extremely small female skull from Kryshtaleva Cave. We provide a direct AMS date for this specimen (22.0–21.5 cal kyr BP), which suggests that the Kryshtaleva lioness must have belonged to a Panthera spelaea spelaea population forced south by the spreading ice sheet. We discuss some palaeoecological aspects of the evolutionary history and eventual extinction of the cave lion. Finally, we review the subfossil records of the extant lion Panthera leo known from several Ukrainian sites archaeologically dated to 6.4–2.0 kyr BP. These finds most probably represent the Persian lion Panthera leo persica
    • …
    corecore