1,689 research outputs found

    High-resolution palynology reveals the land-use history of a Sami renvall in northern Sweden

    Get PDF
    Acknowledgements: This research was funded by the Leverhulme Trust through the Footprints on the Edge of Thule project, and was written under the auspices of the ERC-funded project Arctic Domus. Thanks are offered to Audrey Innes for laboratory assistance; Ian Foster for 210Pb dating; Gordon Cook for AMS radiocarbon analyses; and Martin Konert and the late Sjoerd Bohncke for assistance with LOI and related analyses. The comments of Tim Mighall, Jeff Blackford, Mari Kuoppamaa, two anonymous referees and the editor helped to improve the paper.Peer reviewedPublisher PD

    A Holder Continuous Nowhere Improvable Function with Derivative Singular Distribution

    Full text link
    We present a class of functions K\mathcal{K} in C0(R)C^0(\R) which is variant of the Knopp class of nowhere differentiable functions. We derive estimates which establish \mathcal{K} \sub C^{0,\al}(\R) for 0<\al<1 but no KKK \in \mathcal{K} is pointwise anywhere improvable to C^{0,\be} for any \be>\al. In particular, all KK's are nowhere differentiable with derivatives singular distributions. K\mathcal{K} furnishes explicit realizations of the functional analytic result of Berezhnoi. Recently, the author and simulteously others laid the foundations of Vector-Valued Calculus of Variations in LL^\infty (Katzourakis), of LL^\infty-Extremal Quasiconformal maps (Capogna and Raich, Katzourakis) and of Optimal Lipschitz Extensions of maps (Sheffield and Smart). The "Euler-Lagrange PDE" of Calculus of Variations in LL^\infty is the nonlinear nondivergence form Aronsson PDE with as special case the \infty-Laplacian. Using K\mathcal{K}, we construct singular solutions for these PDEs. In the scalar case, we partially answered the open C1C^1 regularity problem of Viscosity Solutions to Aronsson's PDE (Katzourakis). In the vector case, the solutions can not be rigorously interpreted by existing PDE theories and justify our new theory of Contact solutions for fully nonlinear systems (Katzourakis). Validity of arguments of our new theory and failure of classical approaches both rely on the properties of K\mathcal{K}.Comment: 5 figures, accepted to SeMA Journal (2012), to appea

    Effective communications on invasive alien species: Identifying communication needs of Swedish domestic garden owners

    Get PDF
    Invasive alien species threaten biodiversity with domestic gardens acting as a major pathway for the introduction of alien species. Even though the Nordic region is not currently a hotspot for biological invasions, the number of invasions in the Nordic area has been predicted to increase due to climate change. Given a time lag between introduction and invasion, many non-invasive horticultural alien species already introduced into gardens may become invasive in the future. This study aimed to identify the communication needs of Swedish garden owners regarding their management of invasive alien species. A survey among domestic garden owners, informed by topic specialists and local area experts, and interviews with garden owners were conducted in three different bio-climatic areas in a latitudinal gradient across Sweden. The questions targeted invasive alien species and their relations to biodiversity loss and climate change, as well as measures taken to control these species. Analysing the survey data collected in relation to measures taken to control invasive species, Bayesian Additive Regression Tree (BART) modelling was used to identify geographically varying communication needs of the domestic garden owners. In all study areas, the garden owners' measures taken to control invasive alien species were correlated with their strength of beliefs in having experienced local biodiversity loss. A majority of the garden owners were, moreover, uncertain about the impact of climate change on the invasiveness of alien species. In addition, the garden owners' capacity for identifying invasive alien species was often in need of improvement, in particular with respect to the species Impatiens glandulifera, Reynoutria japonica and Rosa rugosa. The results suggest that the evidence-based guidelines for effective communications we developed, have the potential to help communicators meet the local communication needs of garden owners across Sweden, in relation to the management of invasive alien garden species

    A Maturity Assessment Framework for Conversational AI Development Platforms

    Full text link
    Conversational Artificial Intelligence (AI) systems have recently sky-rocketed in popularity and are now used in many applications, from car assistants to customer support. The development of conversational AI systems is supported by a large variety of software platforms, all with similar goals, but different focus points and functionalities. A systematic foundation for classifying conversational AI platforms is currently lacking. We propose a framework for assessing the maturity level of conversational AI development platforms. Our framework is based on a systematic literature review, in which we extracted common and distinguishing features of various open-source and commercial (or in-house) platforms. Inspired by language reference frameworks, we identify different maturity levels that a conversational AI development platform may exhibit in understanding and responding to user inputs. Our framework can guide organizations in selecting a conversational AI development platform according to their needs, as well as helping researchers and platform developers improving the maturity of their platforms.Comment: 10 pages, 10 figures. Accepted for publication at SAC 2021: ACM/SIGAPP Symposium On Applied Computin

    A nonhomogeneous boundary value problem in mass transfer theory

    Full text link
    We prove a uniqueness result of solutions for a system of PDEs of Monge-Kantorovich type arising in problems of mass transfer theory. The results are obtained under very mild regularity assumptions both on the reference set ΩRn\Omega\subset\mathbf{R}^n, and on the (possibly asymmetric) norm defined in Ω\Omega. In the special case when Ω\Omega is endowed with the Euclidean metric, our results provide a complete description of the stationary solutions to the tray table problem in granular matter theory.Comment: 22 pages, 2 figure

    Boron Isotope Effect in Superconducting MgB2_2

    Full text link
    We report the preparation method of, and boron isotope effect for MgB2_2, a new binary intermetallic superconductor with a remarkably high superconducting transition temperature TcT_c(10^{10}B) = 40.2 K. Measurements of both temperature dependent magnetization and specific heat reveal a 1.0 K shift in TcT_c between Mg11^{11}B2_2 and Mg10^{10}B2_2. Whereas such a high transition temperature might imply exotic coupling mechanisms, the boron isotope effect in MgB2_2 is consistent with the material being a phonon-mediated BCS superconductor.Comment: One figure and related discussion adde
    corecore