Mackenzie Inuit Lithic Raw Material Procurement in the Lower Mackenzie Valley: The Importance of Social Factors

Oral and written historical records indicate that the Mackenzie Inuit traveled up the Mackenzie River from the Arctic Coast to procure lithic raw material in the interior from a quarry at the mouth of the Thunder River, which is known locally by the Gwich’in of the lower Mackenzie Valley as Vihtr’ii Tshik. We evaluate this proposition using non-destructive polarized energy dispersive X-ray fluorescence to compare the geochemical signatures of the lithic raw material from Vihtr’ii Tshik (MiTi-1) and flakes and tools from the Mackenzie Inuit village of Kuukpak (NiTs-1), which is located more than 400 km downriver of the quarry source. The concentrations of nine selected elements—three major elements expressed as oxides (SiO2, Fe2O3T, and K2O) and six trace elements expressed as metals (Rb, Sr, Y, Zr, Ba, and Ce)—are compared using descriptive statistics, spider diagrams, and principal components analysis. The geochemical effects of chemical weathering on the surfaces of artifacts are evaluated by measuring element concentrations before and after removal of the weathering rind from select artifacts. The results of our analyses demonstrate that the lithic raw material available at Vihtr’ii Tshik is best characterized as chert, and that 86% of the flakes and tools from Kuukpak analyzed in this study are chemically similar to the raw material from Vihtr’ii Tshik. Historical records and archaeological data indicate that the people of Kuukpak traversed a complex social landscape to obtain stone from Vihtr’ii Tshik through direct procurement.Les traditions orales et écrites historiques indiquent que les Inuits du Mackenzie remontaient le fleuve Mackenzie en quittant la côte arctique et allant vers l’intérieur des terres afin d’obtenir de la matière première lithique d’une carrière qui se trouvait près de l’embouchure de la rivière Thunder. Les Gwich’in de la basse vallée du Mackenzie appellent cet endroit Vihtr’ii Tshik. Nous évaluons ces révélations en utilisant la technique de fluorescence par rayons X en mode dispersion d’énergie (géométrie polarisante, méthode non destructive) afin de comparer les signatures géochimiques des roches trouvées à la carrière Vihtr’ii Tshik (MiTi-1) avec celles des éclats et des outils en pierre provenant d’un site villageois inuit appelé Kuukpak (NiTs-1) qui se trouve à 400 km en aval de la carrière. Les concentrations de neuf éléments chimiques — trois éléments majeurs exprimés sous la forme d’oxydes (SiO2, Fe2O3T et K2O) et six éléments traces exprimés sous la forme de métaux (Rb, Sr, Y, Zr, Ba et Ce) — sont utilisées pour calculer des statistiques descriptives et des diagrammes-araignées, et réaliser une analyse multivariée par composantes principales. Nous évaluons aussi les effets géochimiques causés par l’intempérisation de la surface des artefacts en mesurant les concentrations d’éléments avant et après l’enlèvement de celle-ci sur des artefacts sélectionnés. Les résultats de nos analyses chimiques démontrent que la roche provenant de la carrière Vihtr’ii Tshik est un chert, et que 86 % des éclats et outils analysés dans cette étude provenant du site villageois Kuukpak montrent des affinités géochimiques au chert de cette carrière. Les documents historiques et les données archéologiques nous indiquent que les gens de Kuukpak devaient naviguer à travers une géographie culturelle complexe afin de se procurer directement le chert de la carrière de Vihtr’ii Tshik

Experimental investigation of the impact of room/system design on mixed convection heat transfer

Night cooling attracts growing interest. However, architects and engineers still hesitate to apply night cooling because of the important but hard-to-predict convective heat transfer by night. Obviously, this heat transfer mechanism depends on the driving force, fluid motion and heat transfer surface and, thus, on the room and system design. Unfortunately, studies addressing this are scarce. In response, underlying experimental effort intends to instigate global parametric analyses of night cooling at room level. To this end, this study, held in a PASLINK cell, investigates how the ventilative cooling rate, thermal mass and the supply/exhaust configuration affect the convective heat transfer. The analysis is based on airflow data, such as temperature and velocity, and the related convective heat flux. The results indicate the need for an integrated room/system design. After all, the position of the supply relative to thermally massive elements predominates the night cooling performance

Experimental analysis of the impact of room/system design on night ventilation performance

Night cooling attracts growing interest. However, building designers still hesitate to apply night cooling because of the important but hard-to-predict convective heat transfer by night. This heat transfer mechanism depends on the driving force, fluid motion and heat transfer surface and, thus, on the room/system design. Unfortunately, studies addressing this for night cooling regimes are scarce. In response, this study, held in a PASLINK cell, investigates how the ventilative cooling rate, thermal mass and the supply/exhaust configuration affect the convective heat transfer. The analysis is based on airflow data, such as temperature and velocity, and the related convective heat flux. The results indicate the air supply/exhaust configuration is particularly important in case of heterogeneously distributed thermal mass. Next to it, correlations should not be used when the setup and the convection regime differ a lot from those of the corresponding experiments

Applications of the wave packet method to resonant transmission and reflection gratings

Scattering of femtosecond laser pulses on resonant transmission and reflection gratings made of dispersive (Drude metals) and dielectric materials is studied by a time-domain numerical algorithm for Maxwell's theory of linear passive (dispersive and absorbing) media. The algorithm is based on the Hamiltonian formalism in the framework of which Maxwell's equations for passive media are shown to be equivalent to the first-order equation, $\partial \Psi/\partial t = {\cal H}\Psi$, where ${\cal H}$ is a linear differential operator (Hamiltonian) acting on a multi-dimensional vector $\Psi$ built of the electromagnetic inductions and auxiliary matter fields describing the medium response. The initial value problem is then solved by means of a modified time leapfrog method in combination with the Fourier pseudospectral method applied on a non-uniform grid that is constructed by a change of variables and designed to enhance the sampling efficiency near medium interfaces. The algorithm is shown to be highly accurate at relatively low computational costs. An excellent agreement with previous theoretical and experimental studies of the gratings is demonstrated by numerical simulations using our algorithm. In addition, our algorithm allows one to see real time dynamics of long leaving resonant excitations of electromagnetic fields in the gratings in the entire frequency range of the initial wide band wave packet as well as formation of the reflected and transmitted wave fronts.Comment: 23 pages; 8 figures in the png forma

Caractérisation des propriétés mécaniques de vernis photopolymères par micro-indentation et simulation par éléments finis.

Afin de caractériser les propriétés mécaniques de vernis photopolymérisés d’épaisseurs 15 et 80 µm, des essais par Analyse Mécanique Dynamique (D.M.A.) et par micro-indentation ont été menés. Les résultats expérimentaux sont confrontés au moyen de simulations par éléments finis (Abaqus). Un premier modèle viscoélastique a permis de simuler correctement la charge et le plateau de fluage, mais s’avère insuffisant pour simuler la décharge

Direct Translocation as Major Cellular Uptake for CADY Self-Assembling Peptide-Based Nanoparticles

Cell penetrating peptides constitute a potent approach to overcome the limitations of in vivo siRNA delivery. We recently proposed a peptide-based nanoparticle system, CADY, for efficient delivery of siRNA into numerous cell lines. CADY is a secondary amphipathic peptide that forms stable complexes with siRNA thereby improving both their cellular uptake and biological response. With the aim of understanding the cellular uptake mechanism of CADY:siRNA complexes, we have combined biochemical, confocal and electron microscopy approaches. In the present work, we provide evidence that the major route for CADY:siRNA cellular uptake involves direct translocation through the membrane but not the endosomal pathway. We have demonstrated that CADY:siRNA complexes do not colocalize with most endosomal markers and remain fully active in the presence of inhibitors of the endosomal pathway. Moreover, neither electrostatic interactions with cell surface heparan sulphates nor membrane potential are essential for CADY:siRNA cell entry. In contrast, we have shown that CADY:siRNA complexes clearly induce a transient cell membrane permeabilization, which is rapidly restored by cell membrane fluidity. Therefore, we propose that direct translocation is the major gate for cell entry of CADY:siRNA complexes. Membrane perturbation and uptake are driven mainly by the ability of CADY to interact with phospholipids within the cell membrane, followed by rapid localization of the complex in the cytoplasm, without affecting cell integrity or viability

Stability in a network economy: The role of institutions

We consider an economy in which agents are embedded in a network of potential value-generating relationships. Agents are assumed to be able to participate in three types of economic interactions: Autarkic self-provision; bilateral interaction; and multilateral collaboration through endogenously provided platforms. We introduce two stability concepts and provide sufficient and necessary conditions on the network structure that guarantee existence, in cases of the absence of externalities, link-based externalities and crowding externalities. We show that institutional arrangements based on socioeconomic roles and leadership guarantee stability. In particular, the stability of more complex economic outcomes requires more strict and complex institutional rules to govern economic interactions. We investigate strict social hierarchies, tiered leadership structures and global market places

Indentation de films minces Ti1-xAlxN (0=x=1) : analyse mécanique et structurale

Des films minces Ti1-xAlxN (0 x 1) ont été étudiés par DRX, puis par microindentation associée à de la simulation par éléments finis. Les empreintes d'indentation sont analysées à partir d'images MET sur des lames amincies par FIB. Les résultats montrent des relations entre la structure cristalline, le mode de croissance et l'endommagement des couches en fonction de x. La forte proportion de joints de grains dans les films riches en Ti permet un glissement des zones cristallines sous l'effet des contraintes de cisaillement. Les films riches en Al sont plus texturés et fragiles

State of the art on full scale testing and dynamic data analysis for building energy performance characterisation

The paper gives an overview and evaluation of previous and ongoing in situ test activities to characterize energy performance of building components and whole buildings. Examples of full scale test facilities available at different institutes over the world are presented. An overview is given of common methods to analyse dynamic data, with their advantages and drawbacks