824 research outputs found
Accurate crop yield predictions from modelling tree-crop interactions in gliricidia-maize agroforestry
Agroforestry systems, containing mixtures of trees and crops, are often promoted because the net effect of interactions between woody and herbaceous components is thought to be positive if evaluated over the long term. From a modelling perspective, agroforestry has received much less attention than monocultures. However, for the potential of agroforestry to impact food security in Africa to be fully evaluated, models are required that accurately predict crop yields in the presence of trees. The positive effects of the fertiliser tree gliricidia (Gliricidia sepium) on maize (Zea mays) are well documented and use of this tree-crop combination to increase crop production is expanding in several African countries. Simulation of gliricidia-maize interactions can complement field trials by predicting crop response across a broader range of contexts than can be achieved by experimentation alone. We tested a model developed within the APSIM framework. APSIM models are widely used for one dimensional (1D), process-based simulation of crops such as maize and wheat in monoculture. The Next Generation version of APSIM was used here to test a 2D agroforestry model where maize growth and yield varied spatially in response to interactions with gliricidia. The simulations were done using data for gliricidia-maize interactions over two years (short-term) in Kenya and 11 years (long-term) in Malawi, with differing proportions of trees and crops and contrasting management. Predictions were compared with observations for maize grain yield, and soil water content. Simulations in Kenya were in agreement with observed yields reflecting lower observed maize germination in rows close to gliricidia. Soil water content was also adequately simulated, except for a tendency for slower simulated drying of the soil profile each season. Simulated maize yields in Malawi were also in agreement with observations. Trends in soil carbon over a decade were similar to those measured, but could not be statistically evaluated. These results show that the agroforestry model in APSIM Next Generation adequately represented tree-crop interactions in these two contrasting agro-ecological conditions and agroforestry practices. Further testing of the model is warranted to explore tree-crop interactions under a wider range of environmental conditions
Diastolic Ventricular Interaction in Heart Failure With Preserved Ejection Fraction
Background Exerciseâinduced pulmonary hypertension is common in heart failure with preserved ejection fraction (HFpEF). We hypothesized that this could result in pericardial constraint and diastolic ventricular interaction in some patients during exercise. Methods and Results Contrast stress echocardiography was performed in 30 HFpEF patients, 17 hypertensive controls, and 17 normotensive controls (healthy). Cardiac volumes, and normalized radius of curvature (NRC) of the interventricular septum at endâdiastole and endâsystole, were measured at rest and peakâexercise, and compared between the groups. The septum was circular at rest in all 3 groups at endâdiastole. At peakâexercise, endâsystolic NRC increased to 1.47±0.05 (P<0.001) in HFpEF patients, confirming development of pulmonary hypertension. Endâdiastolic NRC also increased to 1.54±0.07 (P<0.001) in HFpEF patients, indicating septal flattening, and this correlated significantly with endâsystolic NRC (Ï=0.51, P=0.007). In hypertensive controls and healthy controls, peakâexercise endâsystolic NRC increased, but this was significantly less than observed in HFpEF patients (HFpEF, P=0.02 versus hypertensive controls; P<0.001 versus healthy). There were also small, nonâsignificant increases in endâdiastolic NRC in both groups (hypertensive controls, +0.17±0.05, P=0.38; healthy, +0.06±0.03, P=0.93). In HFpEF patients, peakâexercise endâdiastolic NRC also negatively correlated (r=â0.40, P<0.05) with the change in left ventricular endâdiastolic volume with exercise (ie, the FrankâStarling mechanism), and a trend was noted towards a negative correlation with change in stroke volume (r=â0.36, P=0.08). Conclusions Exercise pulmonary hypertension causes substantial diastolic ventricular interaction on exercise in some patients with HFpEF, and this restriction to left ventricular filling by the right ventricle exacerbates the preâexisting impaired FrankâStarling response in these patients
Using e-learning to support international students' dissertation preparation
Purpose: A research paper on the design and implementation of an e-learning resource responding to the globalisation of education. The purpose of this paper is to focus on the challenges presented in learning and teaching on how to support international postgraduate (PG) students undertaking the specific task of a dissertation.
Design/methodology/approach: Using findings from 250 PG students, 40 supervisors and two module tutors the research identified the content and language issues faced by students and recognised the need to design an enabler supporting the latter as independent learners and the academic staff delivering support.
Findings: The e-learning tool provides an independent learning tool which addresses student concerns relating to the process and content of structuring a dissertation and the function of language. Initial responses have been positive from both staff and students in respect to providing a source of student support and feedback.
Originality/value: The research shows how the Dissertation Game Model (DGM), evolved into an e-learning resource supporting student understanding of the content, structure, planning and writing of a dissertation. The e-learning tool focuses on helping international students understand what the generic contents of each chapter of a dissertation should contain and supports them in engaging in research as a transferable skill
Online training courses on Expert Knowledge Elicitation (EKE)
This report summarises the training courses delivered under the contract OC/EFSA/AMU/2021/02 EKE: âDevelop and conduct online training courses on Expert Knowledge Elicitation (EKE)â. The objective of the courses was to develop and conduct online training courses on applying the methodology described in the EFSA Guidance on Expert Knowledge Elicitation in Food and Feed Safety Risk Assessmentâ for EFSA staff and experts, as well as corresponding experts from EU member states. In addition to the three standard EKE methods (Sheffield, Delphi and Cooke), the training included a semi-formal method of EKE. All these methods may be used when EKE is performed within an existing EFSA working group to support uncertainty analysis as outlined in âThe principles and methods behind EFSA's Guidance on Uncertainty Analysis in Scientific Assessmentâ. In total, 12 courses were organised: two on âSteering an Expert Knowledge Elicitationâ, two on âConduct of the Sheffield protocol for an EKEâ, one on âConduct of the Cooke protocol for an EKEâ, one on âConduct of the Delphi protocol for an EKEâ, two on âConduct of a Semi-formal EKEâ, two on âReporting an Expert Knowledge Elicitationâ and two on âWriting an Evidence Dossier for an Expert Knowledge Elicitationâ. The courses had in total 149 participants and received very good feedback from the participants with a mean value of 4.2 of 5 possible, considering all numerical questions in the feedback questionnaire. Recommendations for future activities on training EKE methodologies are provided
LHCb Upgraded RICH 1 Engineering Design Review Report
During the Long Shutdown 2 of the LHC, the LHCb collaboration will replace the upstream
Ring Imaging Cherenkov detector (RICH 1). The magnetic shield of the current RICH 1
will be modified, new spherical and plane mirrors will be installed and a new gas enclosure
will be manufactured. New photon detectors (multianode photomultiplier tubes) will be
used and these, together with their readout electronics, require a new mechanical support
system. This document describes the new optical arrangement of RICH 1, its engineering
design, installation and alignment. A summary of the project schedule and institute
responsibilities is provided
LHCb Upgraded RICH 1 Engineering Design Review Report
During the Long Shutdown 2 of the LHC, the LHCb collaboration will replace the upstream
Ring Imaging Cherenkov detector (RICH 1). The magnetic shield of the current RICH 1
will be modified, new spherical and plane mirrors will be installed and a new gas enclosure
will be manufactured. New photon detectors (multianode photomultiplier tubes) will be
used and these, together with their readout electronics, require a new mechanical support
system. This document describes the new optical arrangement of RICH 1, its engineering
design, installation and alignment. A summary of the project schedule and institute
responsibilities is provided
Present and Future CP Measurements
We review theoretical and experimental results on CP violation summarizing
the discussions in the working group on CP violation at the UK phenomenology
workshop 2000 in Durham.Comment: 104 pages, Latex, to appear in Journal of Physics
The role of school level protective factors in overcoming cumulative risk for behaviour difficulties in children with special educational needs and disabilities
The study investigated whether school level protective factors could moderate the effects cumulative risk has upon behaviour difficulties in children with Special Educational Needs and Disabilities (SEND). The sample comprised 4288 children identified with SEND: 2660 pupils within 248 primary schools, and 1628 pupils within 57 secondary schools. Risk factors associated with increases in behaviour difficulties over an 18-month period were summed to a cumulative risk score. Various school level factors were added to multi-level models, with interaction terms computed between cumulative risk and these variables to assess their potential protective effects. The primary school model revealed a significant interaction between cumulative risk and school academic achievement in predicting behaviour difficulties. Higher levels of achievement in primary schools help reduce behaviour difficulties for children most at risk. The secondary school model evidenced a significant interaction between cumulative risk and school percentage of students eligible for free school meals (FSM). Lower proportions within a school of children eligible for FSM were associated with reductions in behaviour difficulties for children at high levels of risk. Interventions aimed at improving school level academic achievement and targeting high-risk students attending schools with large proportions of children eligible for FSM would be beneficial
Effects of antiplatelet therapy on stroke risk by brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases: subgroup analyses of the RESTART randomised, open-label trial
Background
Findings from the RESTART trial suggest that starting antiplatelet therapy might reduce the risk of recurrent symptomatic intracerebral haemorrhage compared with avoiding antiplatelet therapy. Brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases (such as cerebral microbleeds) are associated with greater risks of recurrent intracerebral haemorrhage. We did subgroup analyses of the RESTART trial to explore whether these brain imaging features modify the effects of antiplatelet therapy
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