title: Temperature and plant genotype alter alkaloid concentrations in ryegrass infected with an epichloё endophyte and this affects an insect herbivore.

authors: Henessey, Louise M.

abstract: Asexual Epichloё endophytes colonise agricultural forage grasses in a relationship which is mutually beneficial and provides the host plant with protection against herbivorous insects. The endophyte strain AR37 (Epichloё festucae var. lolii) produces epoxy-janthitrem alkaloids and is the only endophyte known to provide ryegrass with resistance against porina larvae (Wiseana cervinata (Walker)), a major pasture pest in cooler areas of New Zealand. This study examined the effect of temperature on concentrations of epoxy-janthitrems in AR37-infected ryegrass and determined how the resulting variations in concentration affected consumption, growth and survival of porina larvae. Twenty replicate pairs of perennial (Lolium perenne L.) and Italian ryegrass (Lolium multiflorum Lam.) plants with and without endophyte were prepared by cloning, with one of each pair grown at either high (20°C) or low (7°C) temperature. After 10 weeks, herbage on each plant was harvested, divided into leaf and pseudostem, then freeze dried and ground. Leaf and pseudostem material was then incorporated separately into semi-synthetic diets which were fed to porina larvae in a bioassay over 3 weeks. Epoxy-janthitrem concentrations within the plant materials and the semi-synthetic diets were analysed by HPLC. AR37-infected ryegrass grown at high temperature contained high in planta concentrations of epoxy-janthitrem (30.6 µg/g in leaves and 83.9 µg/g in pseudostems) that had a strong anti-feedant effect on porina larvae when incorporated into their diets, reducing their survival by 25-42% on pseudostems. In comparison, in planta epoxy-janthitrem concentrations in AR37-infected ryegrass grown at low temperature were very low (0.67 µg/g in leaves and 7.4 µg/g in pseudostems) resulting in a small anti-feedant effect in perennial but not in Italian ryegrass. Although alkaloid concentrations were greatly reduced by low temperature this reduction did not occur until after 4 weeks of exposure. Alkaloid concentrations were slightly lower in Italian than in perennial ryegrass and concentrations were higher in the pseudostems when compared with the leaves. In conclusion, epoxy-janthitrems expressed by the AR37 endophyte show strong activity against porina larvae. However, when ryegrass plants are grown at a constant low temperature for an extended period of time in planta epoxy-janthitrem concentrations are greatly reduced and are less

text: Temperature and plant genotype alter alkaloid concentrations in ryegrass infected with an epichloё endophyte and this affects an insect herbivore. Asexual Epichloё endophytes colonise agricultural forage grasses in a relationship which is mutually beneficial and provides the host plant with protection against herbivorous insects. The endophyte strain AR37 (Epichloё festucae var. lolii) produces epoxy-janthitrem alkaloids and is the only endophyte known to provide ryegrass with resistance against porina larvae (Wiseana cervinata (Walker)), a major pasture pest in cooler areas of New Zealand. This study examined the effect of temperature on concentrations of epoxy-janthitrems in AR37-infected ryegrass and determined how the resulting variations in concentration affected consumption, growth and survival of porina larvae. Twenty replicate pairs of perennial (Lolium perenne L.) and Italian ryegrass (Lolium multiflorum Lam.) plants with and without endophyte were prepared by cloning, with one of each pair grown at either high (20°C) or low (7°C) temperature. After 10 weeks, herbage on each plant was harvested, divided into leaf and pseudostem, then freeze dried and ground. Leaf and pseudostem material was then incorporated separately into semi-synthetic diets which were fed to porina larvae in a bioassay over 3 weeks. Epoxy-janthitrem concentrations within the plant materials and the semi-synthetic diets were analysed by HPLC. AR37-infected ryegrass grown at high temperature contained high in planta concentrations of epoxy-janthitrem (30.6 µg/g in leaves and 83.9 µg/g in pseudostems) that had a strong anti-feedant effect on porina larvae when incorporated into their diets, reducing their survival by 25-42% on pseudostems. In comparison, in planta epoxy-janthitrem concentrations in AR37-infected ryegrass grown at low temperature were very low (0.67 µg/g in leaves and 7.4 µg/g in pseudostems) resulting in a small anti-feedant effect in perennial but not in Italian ryegrass. Although alkaloid concentrations were greatly reduced by low temperature this reduction did not occur until after 4 weeks of exposure. Alkaloid concentrations were slightly lower in Italian than in perennial ryegrass and concentrations were higher in the pseudostems when compared with the leaves. In conclusion, epoxy-janthitrems expressed by the AR37 endophyte show strong activity against porina larvae. However, when ryegrass plants are grown at a constant low temperature for an extended period of time in planta epoxy-janthitrem concentrations are greatly reduced and are less

year: 2016

title: Risks and challenges of non-domestic data centres for isolated countries

authors: Wanyonyi, Peter

abstract: Small and isolated nations have been significant early adopters of Cloud Computing services, driven in part by the potential for cost savings and the convenience of not having to build their own Internet and computing infrastructure. This move into the Cloud has not been without challenges - indeed, while these services offer scalability, flexibility, and cost-efficiency, they also expose these nations to unique risks and vulnerabilities. Many of these nations are at significant distances from the Data Centres whose services they consume, introducing unavoidable transmission challenges as well as legal and geopolitical issues for these nations, given their lack of control or enforcement capability over the foreign-hosted data centres whose services they consume.
As case studies, in this work we identify, measure and investigate some of the technical challenges posed by reliance on foreign Cloud Data Centres, and also analyse and discuss the non-technical challenges faced by nations that rely on such facilities. In those case studies, this work also explores how small and isolated nations can navigate these challenges, and recommends courses of action that provide actionable options for such nations. This dissertation also examines the disadvantages and risks associated with the reliance on nondomestic data centres by small, geographically or politically isolated nations where studies of such characteristics are possible, such as New Zealand and Taiwan.

text: Risks and challenges of non-domestic data centres for isolated countries Small and isolated nations have been significant early adopters of Cloud Computing services, driven in part by the potential for cost savings and the convenience of not having to build their own Internet and computing infrastructure. This move into the Cloud has not been without challenges - indeed, while these services offer scalability, flexibility, and cost-efficiency, they also expose these nations to unique risks and vulnerabilities. Many of these nations are at significant distances from the Data Centres whose services they consume, introducing unavoidable transmission challenges as well as legal and geopolitical issues for these nations, given their lack of control or enforcement capability over the foreign-hosted data centres whose services they consume.
As case studies, in this work we identify, measure and investigate some of the technical challenges posed by reliance on foreign Cloud Data Centres, and also analyse and discuss the non-technical challenges faced by nations that rely on such facilities. In those case studies, this work also explores how small and isolated nations can navigate these challenges, and recommends courses of action that provide actionable options for such nations. This dissertation also examines the disadvantages and risks associated with the reliance on nondomestic data centres by small, geographically or politically isolated nations where studies of such characteristics are possible, such as New Zealand and Taiwan.

year: 2024

title: Impact of tephra fall and environmental change: a 1000 year record from Matakana Island, Bay of Plenty, North Island, New Zealand.

authors: Giles, Teresa M.

abstract: Palynological evidence was used to determine the development of vegetation communities on Matakana Island, North Island, New Zealand, over the last 1000 radiocarbon years. The pollen record indicates that changes occurred in the vegetation immediately following fallout deposition of the Kaharoa Tephra approximately 100 km from source at c. 665 years BP. Such changes may be a direct response to the impact of tephra fall, although the possibility of anthropogenic disturbance cannot be discounted. As a result of the eruption some taxa (Leucopogon fasciculatus and Tupeia antarctica) became at least temporarily extinct from the area. Two phases of anthropogenic influence on the environment are recorded in the pollen record: Polynesian, followed by European inhabitation of the island, giving a detailed history of human influence in the area for the millennium.

text: Impact of tephra fall and environmental change: a 1000 year record from Matakana Island, Bay of Plenty, North Island, New Zealand. Palynological evidence was used to determine the development of vegetation communities on Matakana Island, North Island, New Zealand, over the last 1000 radiocarbon years. The pollen record indicates that changes occurred in the vegetation immediately following fallout deposition of the Kaharoa Tephra approximately 100 km from source at c. 665 years BP. Such changes may be a direct response to the impact of tephra fall, although the possibility of anthropogenic disturbance cannot be discounted. As a result of the eruption some taxa (Leucopogon fasciculatus and Tupeia antarctica) became at least temporarily extinct from the area. Two phases of anthropogenic influence on the environment are recorded in the pollen record: Polynesian, followed by European inhabitation of the island, giving a detailed history of human influence in the area for the millennium.

year: 1999-01-01