86 research outputs found

    Improving species distribution models for invasive non‐native species with biologically informed pseudo‐absence selection

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    Aim: We present a novel strategy for species distribution models (SDMs) aimed at predicting the potential distributions of range‐expanding invasive non‐native species (INNS). The strategy combines two established perspectives on defining the background region for sampling “pseudo‐absences” that have hitherto only been applied separately. These are the accessible area, which accounts for dispersal constraints, and the area outside the environmental range of the species and therefore assumed to be unsuitable for the species. We tested an approach to combine these by fitting SDMs using background samples (pseudo‐absences) from both types of background. Location: Global. Taxon: Invasive non‐native plants: Humulus scandens, Lygodium japonicum, Lespedeza cuneata, Triadica sebifera, Cinnamomum camphora. Methods: Presence‐background (or presence‐only) SDMs were developed for the potential global distributions of five plant species native to Asia, invasive elsewhere and prioritised for risk assessment as emerging INNS in Europe. We compared models where the pseudo‐absences were selected from the accessible background, the unsuitable background (defined using biological knowledge of the species’ key limiting factors) or from both types of background. Results: Combining the unsuitable and accessible backgrounds expanded the range of environments available for model fitting and caused biological knowledge about ecological unsuitability to influence the fitted species‐environment relationships. This improved the realism and accuracy of distribution projections globally and, generally, within the species’ ranges. Main conclusions: Correlative SDMs remain valuable for INNS risk mapping and management, but are often criticised for a lack of biological underpinning. Our approach partly addresses this concern by using prior knowledge of species’ requirements or tolerances to define the unsuitable background for modelling, while also accommodating dispersal constraints through considerations of accessibility. It can be implemented with current SDM software and results in more accurate and realistic distribution projections. As such, wider adoption has potential to improve SDMs that support INNS risk assessment

    Pest risk analysis for Myriophyllum heterophyllum

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    Myriophyllum heterophyllum presents an overall high phytosanitary risk for the EPPO region with a low uncertainty rating. The overall likelihood of M. heterophyllum continuing to enter the EPPO region is high. The plant is imported into the EPPO region as a misidentified aquatic species for aquaria and ponds and is already established in Austria, Belgium, France, Germany, Hungary, the Netherlands, Spain and Switzerland. The risk of entry into other EPPO countries through import is considered high. The risk of the species establishing in additional countries is high as movement through irrigation and river systems acts to connect countries, facilitating spread regionally. Spread may be accelerated by recreational activities in water bodies invaded by the weed. Impacts of the species within the EPPO region are likely to be severe (high score rating), including aquatic plant species displacement, habitat dominance and effects on other aquatic organisms

    Pest risk analysis for Alternanthera philoxeroides

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    Alternanthera philoxeroides presents a high phytosanitary risk for the EPPO region with a low uncertainty rating. A. philoxeroides is already present in the EPPO region in France and Italy. Further spread within and between EPPO countries is considered likely. The overall likelihood of A. philoxeroides continuing to enter the EPPO region is medium. It is not clear how this species entered the EPPO region and there are no clear pathways of further introduction, as the species is not widely traded as an aquarium plant or as any other type of living plant material. There may be confusion with A. sessilis, or other Alternanthera species traded for aquarium, ornamental or food purposes. The risk of the species establishing in other EPPO countries is considered high as movement through irrigation and river systems may act to connect countries, facilitating spread regionally, especially through high energy unstable river systems that may encourage fragmentation. Spread may be significantly accelerated by water based recreational activities. The potential high impact of the species within the EPPO region should be considered similar to that seen in other countries where the species has invaded and become established; i.e. Australia and the southern states of North America. Impacts are likely to be more pronounced in countries and regions where the climate most suited to population, establishment, growth and spread

    Predicting the peak growth velocity in the individual child: validation of a new growth model

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    Predicting the peak growth velocity in an individual patient with adolescent idiopathic scoliosis is essential or determining the prognosis of the disorder and timing of the (surgical) treatment. Until the present time, no accurate method has been found to predict the timing and magnitude of the pubertal growth spurt in the individual child. A mathematical model was developed in which the partial individual growth velocity curve was linked to the generic growth velocity curve. The generic curve was shifted and stretched or shrunk, both along the age axis and the height velocity axis. The individual age and magnitude of the PGV were obtained from the new predicted complete growth velocity curve. Predictions were made using 2, 1.5, 1 and 0.5 years of the available longitudinal data of the individual child, starting at different ages. The predicted values of 210 boys and 162 girls were compared to the child’s own original values of the PGV. The individual differences were compared to differences obtained when using the generic growth velocity curve as a standard. Using 2 years of data as input for the model, all predictions of the age of the PGV in boys and girls were significantly better in comparison to using the generic values. Using only 0.5 years of data as input, the predictions with a starting age from 13 to 15.5 years in boys and from 9.5 to 14.5 years in girls were significantly better. Similar results were found for the predictions of the magnitude of the PGV. This model showed highly accurate results in predicting the individual age and magnitude of the PGV, which can be used in the treatment of patients with adolescent idiopathic scoliosis

    The prioritisation of a short list of alien plants for risk analysis within the framework of the Regulation (EU) No. 1143/2014

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    Thirty-seven alien plant species, pre-identified by horizon scanning exercises were prioritised for pest risk analysis (PRA) using a modified version of the EPPO Prioritisation Process designed to be compliant with the EU Regulation 1143/2014. In Stage 1, species were categorised into one of four lists – a Residual List, EU List of Minor Concern, EU Observation List and the EU List of Invasive Alien Plants. Only those species included in the latter proceeded to the risk management stage where their priority for PRA was assessed. Due to medium or high spread potential coupled with high impacts twenty-two species were included in the EU List of Invasive Alien Plants and proceeded to Stage 2. Four species (Ambrosia trifida, Egeria densa, Fallopia baldschuanica and Oxalis pes-caprae) were assigned to the EU Observation List due to moderate or low impacts. Albizia lebbeck, Clematis terniflora, Euonymus japonicus, Lonicera morrowii, Prunus campanulata and Rubus rosifolius were assigned to the residual list due to a current lack of information on impacts. Similarly, Cornus sericea and Hydrilla verticillata were assigned to the Residual List due to unclear taxonomy and uncertainty in native status, respectively. Chromolaena odorata, Cryptostegia grandiflora and Sphagneticola trilobata were assigned to the Residual List as it is unlikely they will establish in the Union under current climatic conditions. In the risk management stage, Euonymus fortunei, Ligustrum sinense and Lonicera maackii were considered a low priority for PRA as they do not exhibit invasive tendencies despite being widely cultivated in the EU over several decades. Nineteen species were identified as having a high priority for a PRA (Acacia dealbata, Ambrosia confertiflora, Andropogon virginicus, Cardiospermum grandiflorum, Celastrus orbiculatus, Cinnamomum camphora, Cortaderia jubata, Ehrharta calycina, Gymnocoronis spilanthoides, Hakea sericea, Humulus scandens, Hygrophila polysperma, Lespedeza cuneata, Lygodium japonicum, Pennisetum setaceum, Prosopis juliflora, Sapium sebiferum, Pistia stratiotes and Salvinia molesta)

    Mechanical properties of tungsten following rhenium ion and helium plasma exposure

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    Mechanical properties of Tungsten (W) samples irradiated with 2 MeV Rhenium (Re) ions and helium (He) plasma were investigated using nanoindentation. It was found that there was an increase in hardness for all samples following separate irradiation with both Re ion and He plasma. A slight increase in hardness was obtained for combined exposures. A comparable increase in hardness was observed for a pure He plasma with a sample temperature of 473 K and 1273 K. Optical interferometry was employed to compare surface modification of the samples. Grazing incidence small angle x-ray scattering confirmed He nano-bubble formation of approximately 1 nm diameter in the higher temperature sample, which was not observed with samples at the lower temperaturesPK, CC and JB acknowledge support from the Future Fellowship Scheme of the Australian Research Council (FT120100289, FT100100825 and FT130101355). This research has also been supported by the Science and Industry Endowment Fund grant (PS034)

    Integrating invasive species policies across ornamental horticulture supply-chains to prevent plant invasions

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    1.Ornamental horticulture is the primary pathway for invasive alien plant introductions. We critically appraise published evidence on the effectiveness of four policy instruments that tackle invasions along the horticulture supply chain: pre-border import restrictions, post-border bans, industry codes of conduct and consumer education. 2.Effective pre-border interventions rely on rigorous risk assessment and high industry compliance. Post-border sales bans become progressively less effective when alien species become widespread in a region. 3.A lack of independent performance evaluation and of public disclosure, limits the uptake and effectiveness of voluntary codes of conduct and discourages shifts in consumer preference away from invasive alien species. 4.Policy implications. Closing the plant invasion pathway associated with ornamental horticulture requires government-industry agreements to fund effective pre- and post-border weed risk assessments that can be subsequently supported by widely adopted, as well as verifiable, industry codes of conduct. This will ensure producers and consumers make informed choices in the face of better targeted public education addressing plant invasions

    Taking the Measure of the Universe: Precision Astrometry with SIM PlanetQuest

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    Precision astrometry at microarcsecond accuracy has application to a wide range of astrophysical problems. This paper is a study of the science questions that can be addressed using an instrument that delivers parallaxes at about 4 microarcsec on targets as faint as V = 20, differential accuracy of 0.6 microarcsec on bright targets, and with flexible scheduling. The science topics are drawn primarily from the Team Key Projects, selected in 2000, for the Space Interferometry Mission PlanetQuest (SIM PlanetQuest). We use the capabilities of this mission to illustrate the importance of the next level of astrometric precision in modern astrophysics. SIM PlanetQuest is currently in the detailed design phase, having completed all of the enabling technologies needed for the flight instrument in 2005. It will be the first space-based long baseline Michelson interferometer designed for precision astrometry. SIM will contribute strongly to many astronomical fields including stellar and galactic astrophysics, planetary systems around nearby stars, and the study of quasar and AGN nuclei. SIM will search for planets with masses as small as an Earth orbiting in the `habitable zone' around the nearest stars using differential astrometry, and could discover many dozen if Earth-like planets are common. It will be the most capable instrument for detecting planets around young stars, thereby providing insights into how planetary systems are born and how they evolve with time. SIM will observe significant numbers of very high- and low-mass stars, providing stellar masses to 1%, the accuracy needed to challenge physical models. Using precision proper motion measurements, SIM will probe the galactic mass distribution and the formation and evolution of the Galactic halo. (abridged)Comment: 54 pages, 28 figures, uses emulateapj. Submitted to PAS

    The IÄžB protein BCL3 controls osteogenesis and bone health

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    Objective: IÄžB protein B-cell lymphoma 3-encoded protein (BCL3) is a regulator of the NF-ÎșB family of transcription factors. NF-ÎșB signalling fundamentally influences the fate of bone-forming osteoblasts and bone-resorbing osteoclasts, but the role of BCL3 in bone biology has not been investigated. The objective of this study was to evaluate BCL3 in skeletal development, maintenance and osteoarthritic pathology. Methods: To assess the contribution of BCL3 to skeletal homeostasis, neonatal mice (n = 6-14) lacking BCL3 (Bcl3−/−) and WT controls were characterised for bone phenotype and density. To reveal the contribution to bone phenotype by the osteoblast compartment in Bcl3−/− mice, transcriptomic analysis of early osteogenic differentiation and cellular function (n = 3-7) were assessed. Osteoclast differentiation and function in Bcl3−/− mice (n = 3-5) was assessed. Adult 20-week Bcl3−/− and WT mice bone phenotype, strength and turnover were assessed. A destabilisation of the medial meniscus (DMM) model of osteoarthritic ostephytogenesis was utilised to understand adult bone formation in Bcl3−/− mice (n = 11-13). Results: Evaluation of Bcl3−/− mice revealed congenitally increased bone density, long bone dwarfism, increased bone biomechanical strength and altered bone turnover. Molecular and cellular characterisation of mesenchymal precursors showed that Bcl3−/− cells display an accelerated osteogenic transcriptional profile that leads to enhanced differentiation into osteoblasts with increased functional activity; which could be reversed with a mimetic peptide. In a model of osteoarthritis-induced osteophytogenesis, Bcl3−/− mice exhibit decreased pathological osteophyte formation (P < 0.05). Conclusion: Cumulatively, these findings demonstrate that BCL3 controls developmental mineralisation to enable appropriate bone formation, whilst in a pathological setting it contributes to skeletal pathology
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