Publications by authors named "Sally Wilkinson"

Background: The outcome measure of neonatal hip screening is usually the radiographic acetabular index.

Objective: To assess the feasibility of magnetic resonance imaging (MRI) without sedation and compare the utility of outcome parameters measured from MRI images.

Materials And Methods: The invitation for MRI scanning at 5 years of age was incorporated into follow-up for babies who had more than one ultrasound examination during treatment or surveillance.

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Daily weather reconstructions (called "reanalyses") can help improve our understanding of meteorology and long-term climate changes. Adding undigitized historical weather observations to the datasets that underpin reanalyses is desirable; however, time requirements to capture those data from a range of archives is usually limited. Southern Weather Discovery is a citizen science data rescue project that recovered tabulated handwritten meteorological observations from ship log books and land-based stations spanning New Zealand, the Southern Ocean, and Antarctica.

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The aim of this study was to determine the relationship of tangent to the lateral roof angle (TLRA), Graf's alpha angle and percentage femoral head cover (PHC) and to observed stability, and to establish intraobserver and interobserver errors for measurement of alpha angle and TLRA. In total, 2235 babies referred to the hip review clinic over a period of 8  years. Intraobserver and interobserver errors were calculated from readings of 383 hip images by an experienced paediatric radiologist and a trainee.

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A better understanding of physiological responses of crops to drought stress is important for ensuring sustained crop productivity under climate change. Here, we studied the effect on 15-day-old maize (Zea mays L.) plants of a 6 d non-lethal period of soil drying [soil water potential (SWP) decreased from -0.

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Published maturation curves for bony acetabular roof or α angle (AA) and percentage femoral head cover (FHC) with age are sparse. We aimed to determine typical values for AA and FHC in 2236 infants referred to a selective ultrasound screening programme. There was increase in the values of first measurement of AA and FHC related to the logarithm of age.

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The mechanism of age-induced decreased stomatal sensitivity to abscisic acid (ABA) and soil drying has been explored here. Older, fully expanded leaves partly lost their ability to close stomata in response to foliar ABA sprays, and soil drying which stimulated endogenous ABA production, while young fully expanded leaves closed their stomata more fully. However, ABA- or soil drying-induced stomatal closure of older leaves was partly restored by pretreating plants with 1-methylcyclopropene (1-MCP), which can antagonize ethylene receptors, or by inoculating soil around the roots with the rhizobacterium Variovorax paradoxus 5C-2, which contains 1-aminocyclopropane-1-carboxylic acid (ACC)-deaminase.

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Two mesotrophic grassland species, Ranunculus acris and Dactylis glomerata were exposed to a range of ozone treatments (16.2-89.5 ppb 24 h mean) and two watering regimes under naturally fluctuating photosynthetically active radiation (PAR), vapour pressure deficit (VPD) and temperature.

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Here we highlight how both the root and shoot environment impact on whole plant hormone balance, particularly under stresses such as soil drying, and relate hormone ratios and relative abundances to processes influencing plant performance and yield under both mild and more severe stress. We discuss evidence (i) that abscisic acid (ABA) and ethylene act antagonistically on grain-filling rate amongst other yield-impacting processes; (ii) that ABA's effectiveness as an agent of stomatal closure can be modulated by coincident ethylene or cytokinin accumulation; and (iii) that enhanced cytokinin production can increase growth and yield by improving foliar stay-green indices under stress, and by improving processes that impact grain-filling and number, and that this can be the result of altered relative abundances of cytokinin and ABA (and other hormones). We describe evidence and novel processes whereby these phenomena are/could be amenable to manipulation through genetic and management routes, such that plant performance and yield can be improved.

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Two common (semi-) natural temperate grassland species, Dactylis glomerata and Ranunculus acris, were grown in competition and exposed to two watering regimes: well-watered (WW, 20-40% v/v) and reduced-watered (RW, 7.5-20% v/v) in combination with eight ozone treatments ranging from pre-industrial to predicted 2100 background levels. For both species there was a significant increase in leaf damage with increasing background ozone concentration.

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Ground-level ozone pollution is already decreasing global crop yields (from ∼2.2-5.5% for maize to 3.

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Competition decreased transpiration from young lettuce plants after 2 days, before any reductions in leaf area became apparent, and stomatal conductance (g(s) ) of lettuce and tomato plants was also reduced. Stomatal closure was not due to hydraulic signals or competition for nutrients, as soil water content, leaf water status and leaf nitrate concentrations were unaffected by neighbours. Competition-induced stomatal closure was absent in an abscisic acid (ABA)-deficient tomato mutant, flacca, indicating a fundamental involvement of ABA.

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Recent reports show ethylene-dependent reductions in stomatal sensitivity to abscisic acid (ABA) under ozone stress. These changes reduce stomatal control of plant water loss in drying soil. Here we review evidence that ABA and ethylene, and interactions between these two stress-induced hormones, control many of the responses of intact plants to drought and ozone stress, with emphasis on effects on stomata and shoot growth.

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Elevated atmospheric ozone concentrations (70 ppb) reduced the sensitivity of stomatal closure to abscisic acid (ABA) in Leontodon hispidus after at least 24 h exposure (1) when detached leaves were fed ABA, and (2) when intact plants were sprayed or injected with ABA. They also reduced the sensitivity of stomatal closure to soil drying around the roots. Such effects could already be occurring under current northern hemisphere peak ambient ozone concentrations.

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The apoplastic pH of intact Forsythiaxintermedia (cv. Lynwood) and tomato (Solanum lycopersicum) plants has been manipulated using buffered foliar sprays, and thereby stomatal conductance (g(s)), leaf growth rate, and plant water loss have been controlled. The more alkaline the pH of the foliar spray, the lower the g(s) and/or leaf growth rate subsequently measured.

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Increasing the nitrate (N) concentration in the rooting substrate above deficiency decreased stomatal conductance and leaf growth rate compared with sufficient N in maize seedlings (Zea mays L.) growing in drying substrate. Novel effects were detected when N in the non-deficient range was supplied directly to the xylem of detached shoots: concentrations above 2.

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Stomatal behaviour of plants in drying soil can be regulated by (long distance) chemical signals that provide the shoot with some measure of water availability. Although much emphasis has been placed on the plant hormone abscisic acid (ABA) as a central component of the signalling process, soil drying will modify the delivery to the shoot of a range of potential chemical signals. Here we consider the role that changes in the xylem sap pH might play in determining the access that ABA has to sites of action on the guard cells.

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