Cut mark analysis of protohistoric bison remains from EfPm-27 utilizing the scanning electron microscope

EfPm-27 is a Protohistoric bison pound and processing site located in Fish Creek Park in Calgary, Alberta. The site exhibited the presence of metal tools and macroscopically deceptive cut marks suggesting the potential for the presence of both metal and stone cut marks. Moulds of selected cut marks from the assemblage were made and examined with the scanning electron microscope (SEM) to verify or negate the use of metal tools for butchery at the site. SEM images of the cut mark moulds reveal micromorphology that is similar to experimental and published stone tool cut mark SEM images. No evidence for the use of metal tools for butchering was identified. Protohistoric sites research could benefit from the use of SEM analysis of cut marks to distinguish between stone and metal tool use. This would provide important secondary evidence for metal trade items in scenarios where such artifacts may be beyond recovery. Conversely, the presence of metal artifacts at a site does not necessarily imply that they were used for butchery and this assertion must be verified by the presence of metal cut marks

Predator scent and presence alter mammal assemblages in the Missouri Ozarks, USA

Species that are vulnerable to predation exhibit a host of behavioral and physiological adaptations toward the avoidance of this outcome: Heightened awareness of surroundings through visual, olfactory, and auditory senses are common ways in which these species avoid detection by predators. While links between direct predator-prey relationships are well established, less is known about how predators can shape overall community structure or the populations of secondary or less frequently consumed prey items. As humans expand into rural areas, the frequency of wildlife conflicts rises. In response, humans look to prevent these events with a variety of methods. One such method is deterrence of nuisance species with olfactory cues from predator urines. However, the efficacy of this method remains unknown. In this thesis, I present two projects. In Section 1, I used data gathered from the Ozark Research Field Station to assess predator urine avoidance by nuisance wildlife (primarily raccoons) at the Missouri S&T Ozark Research Field Station, Newburg, Missouri. I found that the presence of predator urine deterred raccoons from consumption of high-quality food sources. In Section 2, I used a dataset from Tyson Environmental Research Center, Eureka, Missouri to determine mammal community structure in response to captive predator presence. I established concentric buffers around a captive predator zone and examined differences in mammal communities within each buffer. Mammal communities changed as distance from the predator enclosure changed. These results have implications for management of nuisance, game, and predator species in Missouri Ozark ecosystems and extend our understanding of ecological interactions among predators and their prey items --Abstract, page iv

On the Controllability of Parabolic Systems with a Nonlinear Term Involving the State and the Gradient

We present some results concerning the controllability of a quasi-linear parabolic equation (with linear principal part) in a bounded domain of ${\mathbb R}^N$ with Dirichlet boundary conditions. We analyze the controllability problem with distributed controls (supported on a small open subset) and boundary controls (supported on a small part of the boundary). We prove that the system is null and approximately controllable at any time if the nonlinear term $f( y, \nabla y)$ grows slower than $|y| \log^{3/2}(1+ |y| + |\nabla y|) + |\nabla y| \log^{1/2}(1+ |y| + |\nabla y|)$ at infinity (generally, in this case, in the absence of control, blow-up occurs). The proofs use global Carleman estimates, parabolic regularity, and the fixed point method

Null controllability of the heat equation with boundary Fourier conditions: the linear case

In this paper, we prove the global null controllability of the linear heat equation completed with linear Fourier boundary conditions of the form ∂y ∂n + β y = 0. We consider distributed controls with support in a small set and nonregular coefficients β = β(x, t). For the proof of null controllability, a crucial tool will be a new Carleman estimate for the weak solutions of the classical heat equation with nonhomogeneous Neumann boundary conditions.Ministerio de Educación y Cienci

Exact controllability to the trajectories of the heat equation with Fourier boundary conditions: the semilinear case

This paper is concerned with the global exact controllability of the semilinear heat equation (with nonlinear terms involving the state and the gradient) completed with boundary conditions of the form ∂y ∂n + f(y) = 0. We consider distributed controls, with support in a small set. The null controllability of similar linear systems has been analyzed in a previous first part of this work. In this second part we show that, when the nonlinear terms are locally Lipschitz-continuous and slightly superlinear, one has exact controllability to the trajectories.Ministerio de Educación y Cienci

Some controllability results for the N-Dimensional Navier-Stokes and Boussinesq systems with N-1 scalar controls

In this paper we deal with some controllability problems for systems of the Navier-Stokes and Boussinesq kind with distributed controls supported in small sets. Our main aim is to control N-dimensional systems (N + 1 scalar unknowns in the case of the Navier–Stokes equations) with N − 1 scalar control functions. In a first step, we present some global Carleman estimates for suitable adjoint problems of linearized Navier–Stokes and Boussinesq systems. In this way, we obtain null controllability properties for these systems. Then, we deduce results concerning the local exact controllability to the trajectories. We also present (global) null controllability results for some (truncated) approximations of the Navier–Stokes equations.Ministerio de Educación y Cienci

Mantle upwellings and convective instabilities revealed by seismic tomography and helium isotope geochemistry beneath eastern Africa

International audienceThe relationship between intraplate volcanism and continental tectonics has been investigated for North and East Africa using a high resolution three-dimensional anisotropic tomographic model derived from seismic data of a French experiment ''Horn of Africa'' and existing broadband data. The joint inversion for seismic velocity and anisotropy of the upper 400 km of the mantle, and geochemical data reveals a complex interaction between mantle upwellings, and lithosphere. Two kinds of mantle upwellings can be distinguished: The first one, the Afar ''plume'' originates from deeper than 400 km and is characterized by enrichment in primordial 3 He and 3 He/ 4 He ratios higher than those along mid-ocean ridges (MOR). The second one, associated with other Cenozoic volcanic provinces (Darfur, Tibesti, Hoggar, Cameroon), with 3 He/ 4 He ratios similar to, or lower than MOR, is a consequence of shallower upwelling. The presumed asthenospheric convective instabilities are oriented in an east-west direction, resulting from interaction between south-north asthenospheric mantle flow, main plume head and topography on the base of lithosphere

L'utilisation des moteurs de recherche par les jeunes : Impact des connaissances du domaine et des connaissances procédurales sur les stratégies d'exploration visuelle

International audienceDans une expérimentation conduite avec 53 élèves de CM2 utilisant la technique de l'oculométrie, nous tentons de mieux comprendre les stratégies d'exploration visuelle utilisées par de très jeunes usagers lors d'une tâche de recherche d'information sur le Web. Plus précisément, notre étude vise d'une part, à déterminer si plusieurs types de stratégies d'exploration visuelle d'une page de résultats proposés par un moteur de recherche (ou SERP) peuvent être déterminés et d'autre part, si des facteurs psychologiques (ici, les connaissances du domaine et les connaissances procédurales) peuvent influencer ces stratégies. Nos résultats ont principalement montré d'une part, que quatre stratégies d'exploration visuelle peuvent effectivement être distinguées et d'autre part, que le niveau de connaissances procédurales influence ces mêmes stratégies

Biofuel Policies in the Presence of Environmental Externalities Preliminary Version (Please do not quote)

Abstract The objective of this paper is to compare, in a general equilibrium setting with three goods, the relative efficiency of biofuel subsidy and biofuel mandate policies with the laissez-faire solution. The outcomes of these institutional arrangements are also compared to that of the optimal solution. This analysis takes into account several environmental externalities such as those associated with the production of biofuels. Our numerical results, applied to the biodiesel policy of France in 2006, show that both policies decrease the utility of the representative consumer compared to the laissez-faire solution. The biofuel subsidy policy also increases overall emissions