1,955 research outputs found

    Bistability and regular spatial patterns in arid ecosystems.

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    A variety of patterns observed in ecosystems can be explained by resource–concentration mechanisms. A resource–concentration mechanism occurs when organisms increase the lateral flow of a resource toward them, leading to a local concentration of this resource and to its depletion from areas farther away. In resource–concentration systems, it has been proposed that certain spatial patterns could indicate proximity to discontinuous transitions where an ecosystem abruptly shifts from one stable state to another. Here, we test this hypothesis using a model of vegetation dynamics in arid ecosystems. In this model, a resource– concentration mechanism drives a positive feedback between vegetation and soil water availability. We derived the conditions leading to bistability and pattern formation. Our analysis revealed that bistability and regular pattern formation are linked in our model. This means that, when regular vegetation patterns occur, they indicate that the system is along a discontinuous transition to desertification. Yet, in real systems, only observing regular vegetation patterns without identifying the pattern-driving mechanism might not be enough to conclude that an ecosystem is along a discontinuous transition because similar patterns can emerge from different ecological mechanisms

    Нейтрализация ономастической семантики как фактор поэтики: об одном собственном имени в рок-тексте Б. Гребенщикова

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    Исследуется мотивированность поэтонима Аделаида в тексте песни Б. Гребенщикова. Данное имя, являющееся ключевым словом текста, мотивировано на различных текстовых уровнях. Выдвижение собственного имени, производимое на фонетическом и метрическом уровнях и сопровождаемое целенаправленной нейтрализацией его ономастической семантики, способствует превращению данного поэтонима в символ и делает его ключевым словом данного текста.На матеріалі имені Аделаіда у статті були розглянуті лінгвістичні механізми символічногоформування значення. Його символічне значення формується засобами фонетичного та метричного наголоса та нейтралізації деяких онімічних семантичних компонентів.The linguistic mechanisms of symbolic meaning's forming are being studied on the material of name Adelaide. Its symbolic meaning forms by means of phonetic and metrical emphasis and neutralization some of onym's semantic components

    Production and Resource Use of Winter Feed Crops in New Zealand

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    In the South Island of New Zealand (NZ), dairy cow numbers have increased from 1.4 to 2.1 million since 2005 (Statistics, New Zealand, 2014). This has led to a strong demand for winter feed crops in place of pasture, and also for supplementing pasture during lactation. Yields of 19–35 t DM/ha are reported for fodder beet (Beta vulgaris L.) in NZ (Chakwizira et al., 2014) compared with 14–25 t DM/ha for forage kale (Brassica oleracea L.) (Chakwizira et al., 2009) and 18–25 t DM/ha for maize (Zea mays L.). Fodder beet has only recently been widely adopted for its ease of feeding and provision a high energy feed (Matthew et al., 2011). Choice of crop is based on yield potential, feed value and suitability for winter feed management. Nitrogen fertiliser and irrigation practices affect the productivity, profitability, and dynamics of resource use during crop growth; and losses of N during winter in situ feeding. Optimized systems with high water and N use efficiency are sought to reduce potential adverse environmental effects. The objectives were to compare efficiency of water and N use of fodder beet, kale and maize and assess their value to growers

    Sowing Date Affects Dry Matter Yield of Fodder Beet (\u3ci\u3eBeta vulgaris\u3c/i\u3e L.) Crops and Farm Profitability

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    Fodder beet (Beta vulgaris L.) is a high yielding and high energy supplementary ruminant feed. Including the crop in a pasture system means loss in production and additional costs during crop establishment, but economic benefits may be recovered with increased seasonal productivity and feed quality. In this study, the Agricultural Production Systems sIMulator was used to estimate herbage production of a typical dairy farm in the Canterbury region of New Zealand based on using a ryegrass (Lolium perenne L.)-clover (Trifolium repens L.) pasture (“Pasture only”) or pasture in combination with fodder beet as winter feed (“Pasture+Fodder beet (FB)”). Mean yields of pasture were used to estimate the potential pasture yield lost from spraying out paddocks 1 month before establishing fodder beet. Fodder beet (‘Rivage’) yields from a 2014 sowing date trial: 19 September (Sep-FB), 17 October (Oct-FB), 17 November (Nov-FB), and 15 December (Dec-FB) were used. Dry matter (DM) yield was determined on 15 June 2015. Yield was 27 t DM/ha for both Sep-FB and Oct-FB and was reduced by 23 and 32% in Nov-FB and Dec-FB, respectively. The total annual yield for “Pasture only” was 16.7 t DM/ha compared with adjusted yield of 29.5, 30.2, 25.7 and 24.9 t DM/ha for “Pasture+Sep-FB”, “Pasture+Oct-FB”, “Pasture+Nov-FB” and “Pasture+Dec-FB”, respectively. Production cost was NZ0.08/kgDMeachforPasture+SepFBandPasture+OctFB,whichwaslowerthanNZ0.08/kg DM each for “Pasture+Sep-FB” and “Pasture+Oct-FB”, which was lower than NZ0.09/kg DM for “Pasture only”. Production costs increased to NZ0.11/kgDMforPasture+NovFBandNZ0.11/kg DM for “Pasture+Nov-FB” and NZ0.12/kg DM for “Pasture+Dec-FB”, but revenue from sale of surplus feed partially offset these costs. Our results show that sowing in October was the most profitable option. Yield gains from sowing fodder beet in September are unlikely because of low temperatures limiting crop growth. Delaying sowing can increase production costs and yield penalty, but potential returns are greater, compared with “Pasture only”

    Building a corpus of multimodal interaction in your field site

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    Research on video- and audio-recordings of spontaneous naturally-occurring conversation in English has shown that conversation is a rule-guided, practice-oriented domain that can be investigated for its underlying mechanics or structure. Systematic study could yield something like a grammar for conversation. The goal of this task is to acquire a corpus of video-data, for investigating the underlying structure(s) of interaction cross-linguistically and cross-culturally

    Options for Improved Biomass Production in Feeding Systems for Dairying in High Rainfall Environments in New Zealand

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    New Zealand dairy production has expanded into marginal climates and soil types on the premise of excellent profitability and efficient utilisation of forage. Annual pasture production in the cool West Coast of the South Island (rainfall 2042-2933 mm) is15,000 kg. Increased farm production and feeding of high quality biomass, from imported feed or supplementary feed crops grown on- farm, are needed to improve milk solid output. Small plot trials with spring and early summer-sown brassicas, cereals and maize were the focus for development of systems to maximise and manage the seasonal feed supply. The effect of sowing time, fertiliser timing and rate of N and K fertiliser application were studied to quantify the risks of crop failure in the high rainfall and low radiation environment. The aim was to increase forage supply/ha in a predominantly grass-based system and reduce associated risks to environmental sustainability

    Brain Activation by Visual Food-Related Stimuli and Correlations with Metabolic and Hormonal Parameters: A fMRI Study

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    Regional brain activity in 15 healthy, normal weight males during processing of visual food stimuli in a satiated and a hungry state was examined and correlated with neuroendocrine factors known to be involved in hunger and satiated states. Two functional Magnetic Resonance Imaging (fMRI) sessions were performed with a one week interval, after overnight fasting or 1 hour after a standardized meal. Blood samples and appetite assessment were obtained after each fMRI session. Main effects of processing food versus non-food stimuli were observed in the ventral visual stream, including the fusiform gyrus and hippocampal areas bilaterally, significantly more in the fasting state. Leptin concentration correlated negatively with activity in the left hippocampal area and right insula during the satiation condition. A positive correlation between ghrelin and "thought of food" hunger scores were found. The positive correlation between ghrelin and food related activation in the insula areas and the right hippocampus during fasting did not reach significance. Conclusion: The increased activation of food vs non-food pictures in the ventral visual stream reflects increased salience of food pictures when subjects are hungry. Leptin was associated with activations in areas involved in processing of new information and emotion. © Jakobsdottir et al

    Liver microwave ablation:a systematic review of various FDA-approved systems

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    ObjectivesThe aim of the present study is to analyze preclinical and clinical data on the performance of the currently US Food and Drug Administration (FDA)-approved microwave ablation (MWA) systems.MethodsA review of the literature, published between January 1, 2005, and December 31, 2016, on seven FDA-approved MWA systems, was conducted. Ratio of ablation zone volume to applied energy R(AZ:E) and sphericity indices were calculated for ex vivo and in vivo experiments.ResultsThirty-four studies with ex vivo, in vivo, and clinical data were summarized. In total, 14 studies reporting data on ablation zone volume and applied energy were included for comparison R(AZ:E). A significant correlation between volume and energy was found for the ex vivo experiments (r=0.85,

    Building a corpus of spontaneous interaction

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    This revised version supersedes all previous versions (e.g., Field Manual 2010)
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