7,585 research outputs found

    Allocation: A Collective Responsibility

    Get PDF

    On The Simulated Annealing In Rd\mathbf{R}^d

    Full text link
    Using a localization procedure and the result of Holley-Kusuoka-Stroock [7] in the torus, we widely weaken the usual growth assumptions concerning the success of the continuous-time simulated annealing in Rd\mathbf{R}^d. Our only assumption is the existence of an invariant probability measure for a sufficiently low temperature. We also prove, in an appendix, a non-explosion criterion for a class of time-inhomogeneous diffusions.Comment: 22 page

    The Biology of Canadian Weeds. 126. \u3cem\u3eAmaranthus albus\u3c/em\u3e L., \u3cem\u3eA. blitoides\u3c/em\u3e S. Watson and \u3cem\u3eA. blitum\u3c/em\u3e L.

    Get PDF
    A review of biological information is provided for three species of the genus Amaranthus: A. albus L., A. blitoides S. Watson and A. blitum L. The last species has been revised taxonomically and a new subspecies for Canada is presented—A. blitum subsp. emarginatus (Moq. ex Uline & Bray) Carretero, Munoz Garmendia & Pedrol. Amaranthus albus and A. blitoides are native to the U.S.A. and introduced to Canada. Both species are annual ruderal and agrestal weeds. During the past 100 yr the two species have spread across most provinces of Canada, but the greatest frequency and abundance have been recorded in Saskatchewan. Originating from Europe, Asia and North Africa, A. blitum was initially considered a non-persistent species. The present study shows that A. blitum especially, subsp. emarginatus, has continued to spread in QuĂ©bec. The three species are alternate hosts to many insects, nematodes, viruses, bacteria and fungi that affect cultivated plants. In other areas (U.S.A., Europe and Asia), the three species have developed multiple resistance to triazine and acetolactate-synthase-inhibiting herbicides

    The Biology of Canadian Weeds. 131. \u3cem\u3ePolygonum aviculare\u3c/em\u3e L.

    Get PDF
    A review and assessment of biological information as well as personal data are provided for Polygonum aviculare in Canada. The species has been revised taxonomically and the six subspecies that occur in Canada are presented. Three of the subspecies, P. aviculare subsp. aviculare, P. aviculare subsp. neglectum and P. aviculare subsp. depressum are weeds introduced to Canada from Europe. A fourth subspecies, P. aviculare subsp. buxiforme is apparently native to North America. The geographical distribution of the latter four subspecies is very wide. Plants exhibit a high phenotypic plasticity and genetic variability, and they easily adapt to a multitude of agrestal and ruderal habitats. The seeds have a variable dormancy and polymorphic germination as a result of heterocarpy, genetic and environmental factors. In other areas (Europe), the species has developed resistance to triazines. Plants are hosts to nematodes, viruses, and fungi that also affect cultivated plants

    The Biology of Canadian Weeds. 133. \u3cem\u3eCuscuta campestris\u3c/em\u3e Yuncker, \u3cem\u3eC. gronovii\u3c/em\u3e Willd. ex Schult., \u3cem\u3eC. umbrosa\u3c/em\u3e Beyr. ex Hook., \u3cem\u3eC. epithymum\u3c/em\u3e (L.) L. and \u3cem\u3eC. epilinum\u3c/em\u3e Weihe

    Get PDF
    Cuscuta spp. (dodders) are rootless, holoparasitic herbs with filiform stems attached to the host by numerous haustoria. In Canada, Cuscuta gronovii is the most common native species of the genus followed by Cuscuta campestris and C. umbrosa. Cuscuta epithymum and C. epilinum, both introduced species in Canada, occur occasionally. Infestation by Cuscuta spp. can result in serious yield losses and dodders are listed as noxious weeds in British Columbia, Ontario and Québec, and as restricted weeds in Alberta. These plants have evolved special adaptations to ensure their success: germination occurs late in the season when potential hosts are already established; seedlings selectively forage in plant communities and they may survive relatively long periods during the autotrophic stage. Invasion occurs via extremely elaborate mechanisms designed to match the biological processes of their host and bypass defense mechanisms. The principal means of dispersal of Cuscuta weeds world-wide (including Canada) has been through contaminated seeds of previously infested forage legumes. In other areas (e.g., Israel), C. campestris has developed resistance to ALS inhibitors (chlorsulfuron, and sulfometuron-methyl) and AABI herbicides. Complete descriptions and illustrations are provided for discussed species
    • 

    corecore