62 research outputs found

    An Ancient Relation between Units of Length and Volume Based on a Sphere

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    The modern metric system defines units of volume based on the cube. We propose that the ancient Egyptian system of measuring capacity employed a similar concept, but used the sphere instead. When considered in ancient Egyptian units, the volume of a sphere, whose circumference is one royal cubit, equals half a hekat. Using the measurements of large sets of ancient containers as a database, the article demonstrates that this formula was characteristic of Egyptian and Egyptian-related pottery vessels but not of the ceramics of Mesopotamia, which had a different system of measuring length and volume units

    Conception et évaluation d'un nouvel outil de diagnostic utilisant l'Ektacytométrie à gradient osmolaire

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    The ability of red blood cells (RBC) to change their shape under varying conditions is a crucial property allowing these cells to go through capillaries narrower than their own diameter. Ektacytometry is a technique for measuring deformability by exposing a highly diluted blood sample to shear stress and evaluating the resulting elongation in RBC shape using a laser diffraction pattern. This work contributes to the design and evaluation of a new diagnostic technique based on osmotic scan ektacytometry, using a microfluidic method. It allows the measurement of deformability of an RBC population, as a function of varying medium osmolality. This measurement makes possible a differential diagnosis for any one of a number of RBC disorders presenting similar symptoms. It also permits the physician to follow the effects of treatments. Both theoretical aspects based on flow equations and a proof of principle are discussed. This new technique opens up the possibility of building a simple, small footprint instrument described in this work that can be used with finger prick amounts of bloodLa capacité des globules rouges à modifier leur forme en fonction de conditions externes spécifiques représente une propriété fondamentale permettant aux cellules de traverser des capillaires de diamètres plus petits que leur propre diamètre. L’ektacytométrie est une technique utilisée pour mesurer la déformabilité des globules rouges en exposant un échantillon très dilué de sang à des contraintes de cisaillement et en mesurant l’élongation resultante des globules par l'analyse de la figure de diffraction laser. Ce travail contribue à la conception et l’évaluation d’un nouveau dispositif de diagnostic basé sur la méthode microfluidique d'ektacytométrie à gradient osmolaire. Elle permet de mesurer la déformabilité d'une population de globules rouges (RBC), en fonction de l'osmolalité de milieu. Cette mesure permet un diagnostic différentiel d'un certain nombre de troubles de globules rouges présentant des symptômes similaires. Elle permet également de suivre les effets de certains traitements. Des aspects théoriques qui s’appuient sur les équations des écoulements et une preuve de principe sont discutés. Cette nouvelle technique ouvre la possibilité de construire un instrument simple et peu encombrant, décrit dans ce travail, ne nécessitant qu'un prélèvement de sang au bout du doig

    Design and evaluation of a new diagnostic instrument for osmotic gradient ektacytometrie

    No full text
    La capacité des globules rouges à modifier leur forme en fonction de conditions externes spécifiques représente une propriété fondamentale permettant aux cellules de traverser des capillaires de diamètres plus petits que leur propre diamètre. L’ektacytométrie est une technique utilisée pour mesurer la déformabilité des globules rouges en exposant un échantillon très dilué de sang à des contraintes de cisaillement et en mesurant l’élongation resultante des globules par l'analyse de la figure de diffraction laser. Ce travail contribue à la conception et l’évaluation d’un nouveau dispositif de diagnostic basé sur la méthode microfluidique d'ektacytométrie à gradient osmolaire. Elle permet de mesurer la déformabilité d'une population de globules rouges (RBC), en fonction de l'osmolalité de milieu. Cette mesure permet un diagnostic différentiel d'un certain nombre de troubles de globules rouges présentant des symptômes similaires. Elle permet également de suivre les effets de certains traitements. Des aspects théoriques qui s’appuient sur les équations des écoulements et une preuve de principe sont discutés. Cette nouvelle technique ouvre la possibilité de construire un instrument simple et peu encombrant, décrit dans ce travail, ne nécessitant qu'un prélèvement de sang au bout du doigtThe ability of red blood cells (RBC) to change their shape under varying conditions is a crucial property allowing these cells to go through capillaries narrower than their own diameter. Ektacytometry is a technique for measuring deformability by exposing a highly diluted blood sample to shear stress and evaluating the resulting elongation in RBC shape using a laser diffraction pattern. This work contributes to the design and evaluation of a new diagnostic technique based on osmotic scan ektacytometry, using a microfluidic method. It allows the measurement of deformability of an RBC population, as a function of varying medium osmolality. This measurement makes possible a differential diagnosis for any one of a number of RBC disorders presenting similar symptoms. It also permits the physician to follow the effects of treatments. Both theoretical aspects based on flow equations and a proof of principle are discussed. This new technique opens up the possibility of building a simple, small footprint instrument described in this work that can be used with finger prick amounts of bloo

    Reduction of Friction in Oil Pipelines by Polymer Additives

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    Absolute Chronology of Megiddo, Israel, in the Late Bronze and Iron Ages: High-Resolution Radiocarbon Dating

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    International audienceMegiddo (Israel) is a key site for the study of the stratigraphy, chronology, and history of the Bronze andIron ages in the Levant. The article presents a Bayesian chronological model for seven ceramic typology phases and 10stratigraphic horizons at this site, covering the Late Bronze and much of the Iron Age. The model is based on 78 samples,which provided 190 determinations—the most thorough set of radiocarbon determinations known so far in a single site in theLevant. This set of data provides a reliable skeleton for the discussion of cultural processes and historical events in the regionand beyond, including the periods of the Egyptian Empire in Canaan and the Northern Kingdom of Israel

    Algorithmic handwriting analysis of the Samaria inscriptions illuminates bureaucratic apparatus in biblical Israel.

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    Past excavations in Samaria, capital of biblical Israel, yielded a corpus of Hebrew ink on clay inscriptions (ostraca) that documents wine and oil shipments to the palace from surrounding localities. Many questions regarding these early 8th century BCE texts, in particular the location of their composition, have been debated. Authorship in countryside villages or estates would attest to widespread literacy in a relatively early phase of ancient Israel's history. Here we report an algorithmic investigation of 31 of the inscriptions. Our study establishes that they were most likely written by two scribes who recorded the shipments in Samaria. We achieved our results through a method comprised of image processing and newly developed statistical learning techniques. These outcomes contrast with our previous results, which indicated widespread literacy in the kingdom of Judah a century and half to two centuries later, ca. 600 BCE
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