231 research outputs found

    Breeding of CMS-F1-Hybrids in \u3cem\u3eLolium Perenne\u3c/em\u3e With Improved Nitrogen Use Efficiency

    Get PDF
    The environmental pollution by nitrogen losses from dairy farms can be reduced by improving the nitrogen use efficiency (NUE) of grass varieties. The main goal is to develop varieties with a better nitrogen utilisation. These low input varieties can produce acceptable yields at a low level of N-fertilisation. High input varieties express their high yield potential only at high N-supply. These varieties are less preferable, because N- losses increase at higher levels of nitrogen application. The breeding of CMS-F1-Hybrids can be a successful strategy for developing varieties with a higher NUE. In F1-Hybrid varieties higher heterosis effects can be achieved than in populations or synthetic varieties

    Systematic review of the behavioural assessment of pain in cats

    Get PDF
    Objectives The objectives were to review systematically the range of assessment tools used in cats to detect the behavioural expression of pain and the evidence of their quality; and to examine behavioural metrics (considering both the sensory and affective domains) used to assess pain. Methods A search of PubMed and ScienceDirect, alongside articles known to the authors, from 2000 onwards, for papers in English was performed. This was followed by a manual search of the references within the primary data sources. Only peer-reviewed publications that provided information on the assessment tool used to evaluate the behavioural expression of pain in cats, in conscious animals (not anaesthetised cats), were included. Results No previous systematic reviews were identified. One hundred papers were included in the final assessment. Studies were primarily related to the assessment of pain in relation to surgical procedures, and no clear distinction was made concerning the onset of acute and chronic pain. Ten broad types of instrument to assess pain were identified, and generally the quality of evidence to support the use of the various instruments was poor. Only one specific instrument (UNESP-Botucatu scale) had published evidence of validity, reliability and sensitivity at the level of a randomised control trial, but with a positive rather than placebo control, and limited to its use in the ovariohysterectomy situation. The metrics used within the tools appeared to focus primarily on the sensory aspect of pain, with no study clearly discriminating between the sensory and affective components of pain. Conclusions and relevance Further studies are required to provide a higher quality of evidence for methods used to assess pain in cats. Furthermore, a consistent definition for acute and chronic pain is needed. Tools need to be validated that can detect pain in a range of conditions and by different evaluators (veterinary surgeons and owners), which consider both the sensory and emotional aspects of pain

    Fluid management and vasopressor use during colorectal surgery: the search for the optimal balance

    Get PDF
    BackgroundAlthough it is known that excessive intraoperative fluid and vasopressor agents are detrimental for anastomotic healing, optimal anesthesiology protocols for colorectal surgery are currently lacking.ObjectiveTo scrutinize the current hemodynamic practice and vasopressor use and their relation to colorectal anastomotic leakage.DesignA secondary analysis of a previously published prospective observational study: the LekCheck study.Study settingAdult patients undergoing a colorectal resection with the creation of a primary anastomosis.Outcome measuresColorectal anastomotic leakage (CAL) within 30 days postoperatively, hospital length of stay and 30-day mortality.ResultsOf the 1548 patients, 579 (37%) received vasopressor agents during surgery. Of these, 201 were treated with solely noradrenaline, 349 were treated with phenylephrine, and 29 received ephedrine. CAL rate significantly differed between the patients receiving vasopressor agents during surgery compared to patients without (11.8% vs 6.3%, p < 0.001). CAL was significantly higher in the group receiving phenylephrine compared to noradrenaline (14.3% vs 6%, p < 0.001). Vasopressor agents were used more often in patients treated with Goal Directed Therapy (47% vs 34.6%, p < 0.001). There was a higher mortality rate in patients with vasopressors compared to the group without (2.8% vs 0.4%, p = 0.01, OR 3.8). Mortality was higher in the noradrenaline group compared to the phenylephrine and those without vasopressors (5% vs. 0.4% and 1.7%, respectively, p < 0.001). In multivariable analysis, patients with intraoperative vasopressor agents had an increased risk to develop CAL (OR 2.1, CI 1.3-3.2, p = 0.001).ConclusionThe present study contributes to the evidence that intraoperative use of vasopressor agents is associated with a higher rate of CAL. This study helps to create awareness on the (necessity to) use of vasopressor agents in colorectal surgery patients in striving for successful anastomotic wound healing. Future research will be required to balance vasopressor agent dosage in view of colorectal anastomotic leakage

    Information scent, searching and stopping : modelling SERP level stopping behaviour

    Get PDF
    Current models and measures of the \emph{Interactive Information Retrieval (IIR)} process typically assume that a searcher will always examine the first snippet in a given \emph{Search Engine Results Page (SERP)}, and then with some probability or cutoff, he or she will stop examining snippets and/or documents in the ranked list (snippet level stopping). Prior work has however shown that searchers will form an initial impression of the SERP, and will often abandon a page without clicking on or inspecting in detail any snippets or documents. That is, the \emph{information scent} affects their decision to continue. In this work, we examine whether considering the information scent of a page leads to better predictions of stopping behaviour. In a simulated analysis, grounded with data from a prior user study, we show that introducing a SERP level stopping strategy can improve the performance attained by simulated users, resulting in an increase in gain across most snippet level stopping strategies. When compared to actual search and stopping behaviour, incorporating SERP level stopping offers a closer approximation than without. These findings show that models and measures that na\"{i}vely assume snippets and documents in a ranked list are actually examined in detail are less accurate, and that modelling SERP level stopping is required to create more realistic models of the search process

    Uncertainty in Simulating Wheat Yields Under Climate Change

    Get PDF
    Projections of climate change impacts on crop yields are inherently uncertain1. Uncertainty is often quantified when projecting future greenhouse gas emissions and their influence on climate2. However, multi-model uncertainty analysis of crop responses to climate change is rare because systematic and objective comparisons among process-based crop simulation models1,3 are difficult4. Here we present the largest standardized model intercomparison for climate change impacts so far. We found that individual crop models are able to simulate measured wheat grain yields accurately under a range of environments, particularly if the input information is sufficient. However, simulated climate change impacts vary across models owing to differences in model structures and parameter values. A greater proportion of the uncertainty in climate change impact projections was due to variations among crop models than to variations among downscaled general circulation models. Uncertainties in simulated impacts increased with CO2 concentrations and associated warming. These impact uncertainties can be reduced by improving temperature and CO2 relationships in models and better quantified through use of multi-model ensembles. Less uncertainty in describing how climate change may affect agricultural productivity will aid adaptation strategy development and policymaking
    • …
    corecore