499 research outputs found

    Symptom development on two wild, perennial grasses infected by Peronosclerospora species (Family Peronosporaceae: The downy-mildew fungi)

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    The reproductive structures of the downy-mildew fungi, Peronosclerospora nobleiand Peronosclerospora eriochloae, develop only on chlorotic leaves of tall, vegetative tillers of the perennial grasses Sorghum leiocladum (wild sorghum) and Eriochloa pseudoacrotricha (early spring grass), respectively. They are never found on the leaves of flowering tillers, even when tillers of both types grow from the same tussock. The development of symptoms on infected tillers of both hosts and the morphological and anatomical changes to host tissues on infected tillers are detailed

    Evaluation of fungicides for the management of sclerotinia blight of peanut

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    Three trials were conducted in the Burnett region of southern Queensland, Australia, in the 1993–94 and 1994–95 seasons to determine the efficacy of fluazinam, procymidone, and iprodione for managing sclerotinia blight of peanut. Different combinations of rates, nozzle types, and spraying times were used in each trial. Two or 3 sprays of fluazinam at 0.75 and 1.0 kg a.i./ha, and of procymidone at 0.688 and 0.75 kg a.i./ha, were the most effective combinations that reduced disease incidence and increased yield. Iprodione at rates up to 0.5 kg a.i./ha did not significantly improve the yield compared with unsprayed treatments in any trial. In one trial at Tingoora in 1994–95, pre-infection treatments in which the first spray of fluazinam or procymidone was applied before symptoms appeared were more effective than post-infection treatments in which the first spray was applied soon after symptoms were seen. At J. Bjelke-Petersen Research Station (JBPRS) in 1994–95, a banded spray of procymidone at 0.688 kg a.i./ha using a single flat-fan 8004VB nozzle centred over the row significantly increased yield and reduced disease incidence compared with a spray using 3 hollow-cone nozzles (HB4-70) per row, with 1 nozzle over the row and 1 drop nozzle on each side of the row directed at the bases of the plants. At JBPRS in 1993–94, a band spray of fluazinam at 0.333 kg a.i./120 L.ha, applied with a single flat-fan 80015EVB nozzle immediately after the appearance of symptoms, was as effective in reducing the rate of disease development for 3 weeks, as was a directed application using three 80015EVB nozzles at the same time and concentration, but at 3 times the rate per area (1.0 kg a.i./360 L.ha)

    Quantum dot-labelled polymer beads by suspension polymerisation

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    CdSe quantum dots with polymerisable ligands have been incorporated into polystyrene beads, via a suspension polymerisation reaction, as a first step towards the optical encoding of solid supports for application in solid phase organic chemistry

    Changes in the Racial Composition of Phytophthora sojae in Australia Between 1979 and 1996

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    Surveys of commercial soybean fields, disease nurseries, and trial plots of soybean were conducted throughout eastern Australia between 1979 and 1996, and 694 isolates of Phytophthora sojae were collected and classified into races. Fourteen races, 1, 2, 4, 10, 15, and 25, and eight new races, 46 to 53, were identified, but only races 1, 4, 15, 25, 46, and 53 were found in commercial fields. Races 1 and 15 were the only races found in commercial fields in the soybean-growing areas of Australia up until 1989, with race 1 being the dominant race. Race 4 was found in central New South Wales in 1989 on cultivars with the Rps1a gene, and it is now the dominant race in central and southern New South Wales. Races 46 and 53 have only been found once, in southern New South Wales, and race 25 was identified in the same region in 1994 on a cultivar with the Rps1k gene. Only races 1 and 15 have been found in the northern soybean-growing regions, with the latter dominating, which coincides with the widespread use of cultivars with the Rps2 gene. Changes in the race structure of the P. sojae population from commercial fields in Australia follow the deployment of specific resistance genes

    Synergistic Positive Feedback Mechanisms Underlying Seizure Initiation

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    Investigations into seizure initiation, in recent years, have focused almost entirely upon alterations of interneuronal function, chloride homeostasis, and extracellular potassium levels. In contrast, little attention has been directed toward a possible role of dendritic plateau potentials in the actual ictogenic transition, despite a substantial literature dating back 40 years regarding its importance generally in epilepsy. Here, we argue that an increase in dendritic excitability, coordinated across the population of pyramidal cells, is a key stage in ictogenesis

    An examination of the relationship between social interactions and travel uncertainty

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    Recent advances in travel behaviour research hypothesise that travellers, in particular under uncertain conditions, take a number of decisions not in total independence but as members of a social network. The travel decisions could relate to a range of choices including transport mode choice and time of departure. This paper seeks to provide an answer to the following question: Do travellers, both prior and during travelling, refer to their social network when taking travel decisions in uncertain conditions? An internet-based survey was conducted with over 2000 respondents in the two United Kingdom cities of London and Glasgow. Respondents were asked to name those within their social network and to provide information on their contacts including age, gender, relationship length, car availability, and the type and frequency of social interaction. Insights are also provided from the analysis of relationships between an individual’s socio–demographic characteristics, their ego-centric social network, their social interactions and the location in which they live, through the use of clusters analysis, and how this links to two key travel behaviour aspects: who respondents would turn to in particular for advice on travel decisions, and who (and why) they would contact, if they were experiencing an uncertain situation while travelling. It is shown that the first named member of the social network member is a key person for individuals facing travel uncertainty, and that individuals will turn to others, often within their social network, for emotional as well as decision-making support. In addition, older people, those with a lower number of contacts, and those living in smaller households are more likely to decide by themselves in uncertain travel situations

    An optimal ALMA image of the Hubble Ultra Deep Field in the era of JWST: obscured star formation and the cosmic far-infrared background

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    We combine archival ALMA data targeting the Hubble Ultra Deep Field (HUDF) to produce the deepest currently attainable 1-mm maps of this key, extragalactic survey field. Combining all existing data in Band 6, our deepest map covers 4.2arcmin^2, with a beamsize of 1.49"x1.07" at an effective frequency of 243GHz (1.23mm). It reaches an rms of 4.6uJy/beam, with 1.5arcmin^2 below 9.0uJy/beam, an improvement of >5% over the best previously published map and 50% improvement in some regions. We also make a wider, but shallower map, covering 25.4arcmin^2. We detect 45 galaxies in the deep map down to 3.6sigma, including 10 more 1-mm sources than previously detected. 38 of these galaxies have a JWST ID from the JADES NIRCam imaging and the new sources are typically faint and red. A stacking analysis on the positions of ALMA-undetected JADES galaxies yields detections for z<4 and stellar masses from 10^(8.4) to 10^(10.4)Msun, extracting 10% of additional stacked signal from our map compared to previous analyses. Detected sources and stacking contribute (10.0+/-0.5)Jy/deg^2 of the cosmic infrared background (CIB) at 1.23mm. Although this is short of the (uncertain) background level of about 20Jy/deg^2, after taking into account intrinsic fluctuations in the CIB, our measurement is consistent with the background if the HUDF is a mild (~2sigma) negative fluctuation. This suggests that within the HUDF, JWST may have detected essentially all of the galaxies that contribute to the CIB. Our stacking analysis predicts that the field contains around 60 additional galaxies with 1.23mm flux densities averaging around 15uJy, and over 300 galaxies at the few uJy level. However, the contribution of these fainter more modestly-obscured objects to the background is small, and converging, as anticipated from the now well-established strong correlation between galaxy stellar mass and obscured star formation.Comment: Submitted to MNRA

    Genetic Parameters of White Striping and Meat Quality Traits Indicative of Pale, Soft, Exudative Meat in Turkeys (Meleagris gallopavo).

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    Due to the increasing prevalence of growth-related myopathies and abnormalities in turkey meat, the ability to include meat quality traits in poultry breeding strategies is an issue of key importance. In the present study, genetic parameters for meat quality traits and their correlations with body weight and meat yield were estimated using a population of purebred male turkeys. Information on live body, breast, thigh, and drum weights, breast meat yield, feed conversion ratio, breast lightness (L*), redness (a*), and yellowness (b*), ultimate pH, and white striping (WS) severity score were collected on 11,986 toms from three purebred genetic lines. Heritability and genetic and partial phenotypic correlations were estimated for each trait using an animal model with genetic line, hatch week-year, and age at slaughter included as fixed effects. Heritability of ultimate pH was estimated to be 0.34 ± 0.05 and a range of 0.20 ± 0.02 to 0.23 ± 0.02 for breast meat colour (L*, a*, and b*). White striping was also estimated to be moderately heritable at 0.15 ± 0.02. Unfavorable genetic correlations were observed between body weight and meat quality traits as well as white striping, indicating that selection for increased body weight and meat yield may decrease pH and increase the incidence of pale meat with more severe white striping. The results of this analysis provide insight into the effect of current selection strategies on meat quality and emphasize the need to include meat quality traits into future selection indexes for turkeys
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