31 research outputs found

    New Radiocarbon Ages on Percussion-Fractured and Flaked Proboscidean Limb Bones from Yukon, Canada

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    Proboscidean limb bones discovered in Yukon during the 1960s and 1970s exhibit fracture patterns, notches, and bone flakes that are characteristic of percussion. Because of the unique properties of thick cortical proboscidean bone (probably woolly mammoth Mammuthus primigenius or less likely American mastodon Mammut americanum), some researchers hypothesized that these fracture patterns represent intentional hammerstone modification by humans for marrow extraction and bone tool production. As such, these fracture patterns represent evidence of early human dispersal into Eastern Beringia. Radiocarbon dating in the late 1980s indicated that the bone breakage occurred between about 25 000 and 40 000 radiocarbon years before present (14C yr BP). We report 11 new radiocarbon ages using ultra-filtration methods on a different sample of similarly fractured and flaked bones from Yukon. Only two of the radiocarbon ages fall within the expected range of 25 000 to 40 000 14C yr BP. Six other ages are non-finite, with five being more than 49 100 14C yr BP. Three finite ages range between 46 500 and 50 500 14C yr BP with large standard deviations, and these ages may also be non-finite. Two testable hypotheses to explain the observed breakage patterns were developed, the first being that humans broke the bones and the second that some presently unknown geological process broke the bones. Further research is needed to test these two hypotheses.Des ossements de membres de proboscidiens découverts au Yukon dans les années 1960 et 1970 présentent des structures de fractures, des encoches et des traces d’enlèvements d’éclats caractéristiques de la percussion. En raison des propriétés uniques de l’os cortical proboscidien (provenant probablement d’un mammouth laineux Mammuthus primigenius ou, ce qui est moins probable, d’un mastodonte américain Mammut americanum), certains chercheurs ont avancé une hypothèse selon laquelle ces structures représentent des modifications intentionnelles faites au marteau en pierre par des humains, à des fins d’extraction de la moelle et de production d’outils en os. En tant que telles, ces structures de fractures témoignent de la présence ancienne d’humains dans l’est de la Béringie. Vers la fin des années 1980, la datation au radiocarbone a permis de déterminer que les fractures auraient été faites il y a environ 25 000 à 40 000 années radiocarbones avant le présent (14C ans BP). Nous faisons état de 11 nouveaux âges au radiocarbone établis au moyen de méthodes d’ultrafiltration sur un échantillon différent d’os provenant également du Yukon et présentant de semblables fractures et traces d’enlèvements d’éclats. Seulement deux des âges au radiocarbone font partie de la gamme attendue variant entre 25 000 et 40 000 14C ans BP. Six autres âges sont non finis, dont cinq ayant plus de 49 100 14C ans BP. Trois âges finis varient entre 46 500 et 50 500 14C ans BP et ont d’importants écarts-types, et ces âges pourraient également être non finis. Deux hypothèses testables ont été émises afin d’expliquer les structures de fractures observées, la première étant que les fractures ont été causées par des humains et la seconde étant que les fractures sont le résultat d’un processus géologique inconnu à ce jour. Des recherches plus approfondies s’imposent afin de mettre ces deux hypothèses à l’épreuve

    Endogenous production of IL-1B by breast cancer cells drives metastasis and colonisation of the bone microenvironment

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    Background: Breast cancer bone metastases are incurable highlighting the need for new therapeutic targets. After colonizing bone, breast cancer cells remain dormant, until signals from the microenvironment stimulate outgrowth into overt metastases. Here we show that endogenous production of IL-1B by tumor cells drives metastasis and growth in bone. Methods: Tumor/stromal IL-B and IL-1R1 expression was assessed in patient samples and effects of the IL-1R antagonist, Anakinra or the IL-1B antibody Canakinumab on tumor growth and spontaneous metastasis were measured in a humanized mouse model of breast cancer bone metastasis. Effects of tumor cell-derived IL-1B on bone colonisation and parameters associated with metastasis were measured in MDA-MB-231, MCF7 and T47D cells transfected with IL-1B/control. Results: In tissue samples from >1300 patients with stage II/III breast cancer, IL-1B in tumor cells correlated with relapse in bone (hazard ratio 1.85; 95% CI 1.05-3.26; P=0.02) and other sites (hazard ratio 2.09; 95% CI 1.26-3.48; P=0.0016). In a humanized model of spontaneous breast cancer metastasis to bone, Anakinra or Canakinumab reduced metastasis and reduced the number of tumor cells shed into the circulation. Production of IL-1B by tumor cells promoted EMT (altered E-Cadherin, N-Cadherin and G-Catenin), invasion, migration and bone colonisation. Contact between tumor and osteoblasts or bone marrow cells increased IL-1B secretion from all three cell types. IL-1B alone did not stimulate tumor cell proliferation. Instead, IL-1B caused expansion of the bone metastatic niche leading to tumor proliferation. Conclusion: Pharmacological inhibition of IL-1B has potential as a novel treatment for breast cancer metastasis

    Review of \u3ci\u3eFolsom: New Archaeological Investigations of a Classic Paleoindian Bison Kill\u3c/i\u3e. By David J. Meltzer.

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    Well written and well researched, Folsom is appropriate for both avocational and professional audiences as well as for general readers with an interest in archaeology. I was especially drawn to the historical aspects of the research and the analysis of old museum collections. The figures and tables are appropriate, and the artifact illustrations in chapter 8 are of high quality. This excellent book should be in every major public library and in the personal library of everyone interested in Paleoindian studies, the early peopling of the Americas, and the history of archaeology. It is destined to become a classic

    Crossroads of culture: anthropology collections at the Denver Museum of Nature & Science

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    Includes bibliographical references and index.The hectic front of the Denver Museum of Nature & Science hides an unseen back of the museum that is also bustling. Less than 1 percent of the museum's collections arc on display at any given time, and the Department of Anthropology alone cares for more than 50,000 objects from every corner of the globe not normally available to the public. This lavishly illustrated book presents and celebrates rarely seen baskets, jewelry, sculptures, clothing, and other highlights from the Denver Museum of Nature & Science's exceptional anthropology collections. The book presents 123 full-color images to highlight the Museum's cultural treasures. Selected for their individual beauty, historic value, and cultural meaning, these objects connect different places, times, and people. From the mammoth hunters of the Plains to the first American pioneer settlers to the flourishing Hispanic and Asian diasporas in downtown Denver, the Rocky Mountain region has been home to a breathtaking array of cultures. Many objects tell this story of the Rocky Mountains' fascinating and complex past, whereas others serve to bring enigmatic corners of the globe to modern-day Denver. Crossroads of Culture serves as a behind-the-scenes tour of the museum's anthropology collections. All the royalties from this publication will benefit the collections of the Denver Museum of Nature & Science's Department of Anthropology.--Book jacket.One of the great institutions: an introduction -- American ethnology collection -- American archaeology collection -- World archaeology collection -- World ethnology collection -- "Never finished": the anthropology collections today and tomorrow
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