1,150 research outputs found

    Distribution in Australia and seed transmission of tobacco streak virus in parthenium hysterophorus

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    Distribution in Australia and seed transmission of Tobacco streak virus in Parthenium hysterophorus. Plant Dis. 93:708-712. Tobacco streak virus (TSV) was found to commonly occur in Parthenium hysterophorus, as symptomless infections, in central Queensland, Australia across a large area infested with this weed. Several isolates of TSV collected across the geographic range of P. hysterophorus were found to share identical coat protein sequence with each other and with TSV from crop plants in the same area. Seed transmission of TSV in P. hysterophorus was found to occur at rates of 6.8 to 48%. There was almost no change in the rate of TSV seed transmission when P. hysterophorus seed was stored for up to 241/2 months. Implications of this relationship between TSV and P. hysterophorus for the development of virus disease epidemics in surrounding crops are discussed. Ā© 2009 The American Phytopathological Society

    Natural host range, thrips and seed transmission of distinct Tobacco streak virus strains in Queensland, Australia

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    Diseases caused by Tobacco streak virus (TSV) have resulted in significant crop losses in sunflower and mung bean crops in Australia. Two genetically distinct strains from central Queensland, TSV-parthenium and TSV-crownbeard, have been previously described. They share only 81% total-genome nucleotide sequence identity and have distinct major alternative hosts, Parthenium hysterophorus (parthenium) and Verbesina encelioides (crownbeard). We developed and used strain-specific multiplex Polymerase chain reactions (PCRs) for the three RNA segments of TSV-parthenium and TSV-crownbeard to accurately characterise the strains naturally infecting 41 hosts species. Hosts included species from 11 plant families, including 12 species endemic to Australia. Results from field surveys and inoculation tests indicate that parthenium is a poor host of TSV-crownbeard. By contrast, crownbeard was both a natural host of, and experimentally infected by TSV-parthenium but this infection combination resulted in non-viable seed. These differences appear to be an effective biological barrier that largely restricts these two TSV strains to their respective major alternative hosts. TSV-crownbeard was seed transmitted from naturally infected crownbeard at a rate of between 5% and 50% and was closely associated with the geographical distribution of crownbeard in central Queensland. TSV-parthenium and TSV-crownbeard were also seed transmitted in experimentally infected ageratum (Ageratum houstonianum) at rates of up to 40% and 27%, respectively. The related subgroup 1 ilarvirus, Ageratum latent virus, was also seed transmitted at a rate of 18% in ageratum which is its major alternative host. Thrips species Frankliniella schultzei and Microcephalothrips abdominalis were commonly found in flowers of TSV-affected crops and nearby weed hosts. Both species readily transmitted TSV-parthenium and TSV-crownbeard. The results are discussed in terms of how two genetically and biologically distinct TSV strains have similar life cycle strategies in the same environment

    First report ofTobacco streak virus in sunflower (Helianthus annuus), cotton (Gossypium hirsutum), chickpea (Cicer arietinum) and mung bean (Vigna radiata) in Australia

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    Tobacco streak virus (genusIlarvirus) is recorded on sunflower (Helianthus annuus), cotton (Gossypium hirsutum), chickpea (Cicer arietinum) and mung bean (Vigna radiata) in Australia for the first time

    Field evaluation of tolerance to Tobacco streak virus in sunflower germplasm, and observations of seasonal disease spread

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    Strong statistical evidence was found for differences in tolerance to natural infections of Tobacco streak virus (TSV) in sunflower hybrids. Data from 470 plots involving 23 different sunflower hybrids tested in multiple trials over 5 years in Australia were analysed. Using a Bayesian Hierarchical Logistic Regression model for analysis provided: (i) a rigorous method for investigating the relative effects of hybrid, seasonal rainfall and proximity to inoculum source on the incidence of severe TSV disease; (ii) a natural method for estimating the probability distributions of disease incidence in different hybrids under historical rainfall conditions; and (iii) a method for undertaking all pairwise comparisons of disease incidence between hybrids whilst controlling the familywise error rate without any drastic reduction in statistical power. The tolerance identified in field trials was effective against the main TSV strain associated with disease outbreaks, TSV-parthenium. Glasshouse tests indicate this tolerance to also be effective against the other TSV strain found in central Queensland, TSV-crownbeard. The use of tolerant germplasm is critical to minimise the risk of TSV epidemics in sunflower in this region. We found strong statistical evidence that rainfall during the early growing months of March and April had a negative effect on the incidence of severe infection with greatly reduced disease incidence in years that had high rainfall during this period

    Global Standards in Action: Insights from Anti-Money Laundering Regulation

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    As organizations have come under the increasing influence of global rules of all sorts, organization scholars have started studying the dynamics of global regulation. The purpose of this article is to identify and evaluate the contribution to this interdisciplinary field by the ā€˜Stockholm Centre for Organisational Researchā€™. The latterā€™s key proposition is that while global regulation often consists of voluntary best practice rules it can nevertheless become highly influential under certain conditions. We assess how innovative this approach is using as a benchmark the state of the art in another field of relevance to the study of global regulation, i.e. ā€˜International Relationsā€™. Our discussion is primarily theoretical but we draw on the case of global anti-money laundering regulation to illustrate our arguments and for inspirations of how to further elaborate the approach

    Virtual reality:a tool for investigating camouflage

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    Disruptive camouflage utilises high-contrast patches, typically positioned at the margins of an object to impede the detection and/or recognition of a perceiver. To date, the predominant methods for examining camouflage strategies are computer-based (i.e., detection experiments), field-based (e.g., survival analyses) and camouflage choice experiments using dynamically coloured organisms (e.g., cephalopods). Recent advances in virtual reality (VR) technology present the opportunity to create novel environments for testing camouflage theory. VR can combine the control of lab-based research with the ecological validity of field-based studies. Here, we develop an experimental paradigm that enables camouflage testing within a virtual reality environment. The environment comprised a spherical target that can be wrapped with different camouflage patterns and a domed background, upon which a natural image can be projected. Participants were positioned within the centre of the dome and were tasked with finding and shooting at targets randomly positioned across a bounded range within the environment. We manipulated the luminance contrast (0ā€“2 steps of 2.5 L *) of disruptive and edge-enhancement (EE) components of the camouflage patterning to examine their impact on participant response time. Having high, but not extreme, contrast resulted in increased camouflage effectiveness. The EE component had no effect independently but interacted with the DC component. Specifically, when using EE alongside DC, a lower contrast EE component is more effective than a higher contrast EE component. Our results demonstrate that VR is a viable research tool for testing camouflage theory

    On high-speed turning of a third-generation gamma titanium aluminide

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    Gamma titanium aluminides are heat-resistant intermetallic alloys predestined to be employed in components suffering from high mechanical stresses and thermal loads. These materials are regarded as difficult to cut, so this makes process adaptation essential in order to obtain high-quality and defect-free surfaces suitable for aerospace and automotive parts. In this paper, an innovative approach for longitudinal external high-speed turning of a third-generation Ti-45Al-8Nb- 0.2C-0.2B gamma titanium aluminide is presented. The experimental campaign has been executed with different process parameters, tool geometries and lubrication conditions. The results are discussed in terms of surface roughness/integrity, chip morphology, cutting forces and tool wear. Experimental evidence showed that, due to the high cutting speed, the high temperatures reached in the shear zone improve chip formation, so a crack-free surface can be obtained. Furthermore, the use of a cryogenic lubrication system has been identified in order to reduce the huge tool wear, which represents the main drawback when machining gamma titanium aluminides under the chosen process condition

    Fishing on Silba

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    From olden times fishermen from Silba have used different techniques of fishing, depending on weather conditions and season: nets, hooks, tridents and traps. Men matted traps from thatch and used them in the summertime. Hooks, tied on a line and a cane stick, are used when fishing on the shore, or from a boat on the sea. Several hooks on a line (parangal) are used for fishing from a boat in motion, and so is the trident, but in the night-time. The most significant is fish hunting with nets of different forms and names. The catch is sorted according to quality and size, and then better fish is taken to the market of Zadar, and the other is consumed or sold on the island and the neighboring island of Olib

    Real-world clinical experience in the ConnectĀ® chronic lymphocytic leukaemia registry: a prospective cohort study of 1494 patients across 199 US centres.

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    The clinical course of chronic lymphocytic leukaemia (CLL) is heterogeneous, and treatment options vary considerably. The ConnectĀ® CLL registry is a multicentre, prospective observational cohort study that provides a real-world perspective on the management of, and outcomes for, patients with CLL. Between 2010 and 2014, 1494 patients with CLL and that initiated therapy, were enrolled from 199 centres throughout the USA (179 community-, 17 academic-, and 3 government-based centres). Patients were grouped by line of therapy at enrolment (LOT). We describe the clinical and demographic characteristics of, and practice patterns for, patients with CLL enrolled in this treatment registry, providing patient-level observational data that represent real-world experiences in the USA. Fluorescence in situ hybridization (FISH) analyses were performed on 49Ā·3% of patients at enrolment. The most common genetic abnormalities detected by FISH were del(13q) and trisomy 12 (45Ā·7% and 20Ā·8%, respectively). Differences in disease characteristics and comorbidities were observed between patients enrolled in LOT1 and combined LOT2/ā‰„3 cohorts. Important trends observed include the infrequent use of genetic prognostic testing, and differences in patient characteristics for patients receiving chemoimmunotherapy combinations. These data represent experiences of patients with CLL in the USA, which may inform treatment decisions in everyday practice

    In situ XAFS of acid-resilient iridate pyrochlore oxygen evolution electrocatalysts under operating conditions

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    Pyrochlore iridates (Na,Ca)2-xIr2O6?H2O are acid-stable electrocatalysts that are candidates for use in electrolysers and fuel cells. Ir LIII-edge X-ray absorption fine structure spectroscopy in 1 M H2SO4 at oxygen evolution conditions suggests the involvement of the electrons from the conduction band of the metallic particles, rather than just surface iridium reacting
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