82 resultados para morphological types


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Change in morphological and physiological parameters in response to phosphorus (P) supply was studied in 11 perennial herbaceous legume species, six Australian native (Lotus australis, Cullen australasicum, Kennedia prorepens, K. prostrata, Glycine canescens, C. tenax) and five exotic species (Medicago sativa, Lotononis bainesii, Bituminaria bituminosa var albomarginata, Lotus corniculatus, Macroptilium bracteatum). We aimed to identify mechanisms for P acquisition from soil. Plants were grown in sterilised washed river sand; eight levels of P as KH2PO4 ranging from 0 to 384 μg P g−1 soil were applied. Plant growth under low-P conditions strongly correlated with physiological P-use efficiency and/or P-uptake efficiency. Taking all species together, at 6 μg P g−1 soil there was a good correlation between P uptake and both root surface area and total root length. All species had higher amounts of carboxylates in the rhizosphere under a low level of P application. Six of the 11 species increased the fraction of rhizosphere citrate in response to low P, which was accompanied by a reduction in malonate, except L. corniculatus. In addition, species showed different plasticity in response to P-application levels and different strategies in response to P deficiency. Our results show that many of the 11 species have prospects for low-input agroecosystems based on their high P-uptake and P-use efficiency.

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Culex pipiens s.l. is one of the primary vectors of West Nile Virus in the USA and Continental Europe. The seasonal abundance and eco-behavioural characteristics of the typical form, Cx. pipiens pipiens, make it a key putative vector in Britain. Surveillance of Culex larvae and adults is essential to detect any changes to spatial and seasonal activity or morphological traits that may increase the risk of disease transmission. Here we report the use of the modified Reiter gravid box trap, which is commonly used in the USA but scarcely used in the UK, to assess its suitability as a tool for British female Culex mosquito surveillance. Trapping was carried out at 110 sites in urban and rural gardens in Berkshire in May, July and September 2013. We tested if reproductively active adult female Culex are more abundant in urban than rural gardens and if wing characteristic traits and egg raft size are influenced by location and seasonal variations. Gravid traps were highly selective for Culex mosquitoes, on average catching significantly more per trap in urban gardens (32.4 ± 6.2) than rural gardens (19.3 ± 4.0) and more in July than in May or September. The majority of females were caught alive in a good condition. Wing lengths were measured as an indicator of size. Females flying in September were significantly smaller than females in May or July. Further non-significant differences in morphology and fecundity between urban and rural populations were found that should be explored further across the seasons.

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Three sludge types from the same treatment stream (undigested liquid, anaerobically digested liquid and dewatered, anaerobically digested cake) were used in a field based tub study. Amendments (4, 8, and 16 Mg dry solid (ds)ha(-1)) were incorporated into the upper 15 cm of a sandy loam soil prior to sowing with rye-grass (Lolium perenne L.). Nitrogen transformations in the soil were determined for the 80 d period following incorporation. Nitrogen uptake and crop yield were measured in the cut sward 35 and 70 d after sowing. The study showed that application of sewage sludge at rates as low as 4 Mgha(-1) can have a nutritional benefit to rye-grass over the two harvests. Differences in N transformation, and hence crop nutritional benefit, between sludge types were evident throughout the experiment. In particular, the dewatering process changed the mineral N characteristics of the anaerobically digested sludge, which, when not dewatered, outperformed the other sludges in terms of yield and mineralisation rate at both harvests. The dewatered sludge produced the lowest yield of rye-grass. The undigested liquid sludge had the lowest foliar N and soil NO(3)-N concentrations, possibly immobilised as the large oxidisable C component of this sludge was metabolised by the microbial biomass. Correlation data support the concept of preferential uptake of NH(4)-N over NO(3)-N in Lolium perenne. Results are discussed in the context of managing sludge type and application for a plant nutrient source and NO(3)-N release.

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Ιn the eighteenth century the printing of Greek texts continued to be central to scholarship and discourse. The typography of Greek texts could be characterised as a continuation of French models from the sixteenth century, with a gradual dilution of the complexity of ligatures and abbreviations, mostly through printers in the Low Countries. In Britain, Greek printing was dominated by the university presses, which reproduced conservatively the continental models – exemplified by Oxford's Fell types, which were Dutch adaptations of earlier French models. Hindsight allows us to identify a meaningful development in the Greek types cut by Alexander Wilson for the Foulis Press in Glasgow, but we can argue that in the middle of the eighteenth century Baskerville was considering Greek printing the typographic environment was ripe for a new style of Greek types. The opportunity to cut the types for a New Testament (in an twin edition that included a generous octavo and a large quarto version) would seem perfect for showcasing Baskerville's capacity for innovation. His Greek type maintained the cursive ductus of earlier models, but abandoned complex ligatures and any hint of scribal flourish. He homogenised the modulation of the letter strokes and the treatment of terminals, and normalised the horizontal alignments of all letters. Although the strokes are in some letters too delicate, the narrow set of the style composes a consistent, uniform texture that is a clean break from contemporaneous models. The argument is made that this is the first Greek typeface that can be described as fully typographic in the context of the technology of the time. It sets a pattern that was to be followed, without acknowledgement, by Richard Porson nearly a century and a half later. The typeface received little praise by typographic historians, and was condemned by Victor Scholderer in his retrospective of Greek typography. A survey of typeface reviews in the surrounding decades establishes that the commentators were mostly reproducing the views of an arbitrary typographic orthodoxy, for which only types with direct references to Renaissance models were acceptable. In these comments we detect a bias against someone considered an arriviste in the scholarly printing establishment, as well as a conservative attitude to typographic innovation.