Controlling soil erosion in a changing climate: evaluating suitable plant species in grassed waterway design.

Soil erosion is a global problem which needs mitigating due to the on-site and off- site impacts it causes. Soil erosion is set to become an even greater problem due to climate change. Climate change is likely to increase the intensity, frequency and duration of precipitation events. This change in precipitation will increase flow erosivity and thus increase the chance of soil detachment. Grass-based erosion mitigation features will have to be able to withstand a higher volume of water as runoff volumes will increase due to climate change. An increased surface runoff rate will increase sediment transport capacity leading to more soil erosion when coupled with an increased detachment rate therefore solutions for the future need to be researched. Grass-based erosion mitigation features such as swales, buffer strips and grassed water ways (GWWs) have been shown to be effective. In this study, Festulolium Bx511 (F2), Festulolium cv Prior (F1) and a mixture of Festuca rubra and Lolium perenne (C) were used in mixtures and monocultures to investigate their efficacy in mitigating erosion. Experiment 1 used growth rooms under different climatic conditions, a summer scenario (22°C) and an autumn scenario (15°C). There were also different rainfall scenarios, drought (No rainfall), normal (100 % rainfall based on average rainfall (1981 – 2010) average rainfall (1981 – 2010) data from the Met Office) and excess (200 % of average rainfall (1981 – 2010) based on data from the Met Office) to see how they would affect the plant traits needed for erosion control. For summer establishment conditions the normal rainfall value was 49.2 mm, and the excess rainfall was 98.4 mm. For autumn establishment conditions the normal rainfall was 81.9 mm, and the excess value was 163.8 mm. A plant trait ranking system was devised, the species which showed promise were taken forward and used within hydraulic flume experiments to assess actual soil erosion mitigation potential. Plant traits linked to erosion control include both above ground (% cover, plant height, number of stems, number of tillers, stem diameter (mm), stem area density (mm² mm-²), above ground biomass (g) and below ground traits (root total length (cm), root total surface area (cm² ), root diameter (mm) and total root length (cm) of ≤0.25 mm diameter. Climate change is likely to change how grass plant traits are manifest due to the differing climatic conditions. Therefore, any solutions currently promoted that utilise grass monocultures and mixtures for erosion mitigation features such as GWWs may need to be revised to mitigate for climate change. Conclusions from Experiment 1 include that species selection for soil erosion control features such as GWWs must consider potential rainfall and temperature conditions during the grass establishment for optimal erosion control. There were, however, two species combinations which could be considered as year-round candidates, Fest_1+Fest_2+C and C. Experiment 2 was a hydraulic flume experiment where the inflow rates used were 0.2 – 1.4 l s¯¹. Significant differences in the following plant traits; number of stems, number of tillers, stem diameter (mm), stem area density (mm² mm-²), total root length (≤0.25 mm ⌀), total root surface area (cm ² ), and root diameter (mm) were observed between different treatments. Conv had a significantly higher number of stems as compared to all other experimental treatments. Fest_1 had a significantly higher number of tillers, stem diameter and stem area density as compared to all other treatments. Fest_1+Fest_2+C had a significantly higher total root length (≤0.25 mm ⌀) as compared to Conv. Fest_1+2 had a significantly higher total root surface area than the Fest_1 and Fest_1+Fest_2+C experimental treatments. Fest_1+Fest_2 had a significantly higher root diameter as compared to the Fest_1+Fest_2+C experimental treatment. However, significant differences did not manifest in sediment concentration. In conclusion, it did not matter if grass species monocultures or mixtures were used as there were no significant differences in sediment concentration between the experimental grass treatments. Experiment 3 was also a hydraulic flume experiment where the inflow rates used were 0.2 – 2.6 l s¯¹. In this experiment there was a lowered seeding rate (L) and a recommended seeding rate used (N). There were significant differences in plant traits and also in sediment concentration. The critical thresholds for the Environment Agency (EA) major event classification of 1000 mg l¯¹ to be reached were determined for Experiment 3. There were several experimental grass treatments which did not breach the limit set out by the EA (Conv N, Fest_1+2 L, Fest_1 N and Conv L). In conclusion the Conv L, Fest_1 N and Fest_1+2 L species treatments should be recommended for farmers for use in soil erosion mitigation features such as grassed waterways. This thesis was made possible thanks to the soils training and research studentship centre for doctoral training (STARS CDT). It was funded by Biotechnology and Biological Sciences Research Council (BBSRC) and Natural Environment Research Council (NERC), Grant/Award Number: NE-R010218-1.PhD in Environment and Agrifoo

Selecting plant traits for soil erosion control in grassed waterways under a changing climate: A growth room study

Grassed waterways are used to mitigate the offsite transport of sediment generated by soil erosion. This study used a novel trait‐based ranking approach as a method to screen potential candidate grass monocultures and mixes based on their theoretical performance in reducing (1) detachment via rainsplash, (2) detachment via scouring due to concentrated flow and (3) sediment transport and deposition processes. Selected grass species were grown under simulated UK summer and autumn establishment conditions under three different replicated rainfall scenarios: drought, normal rainfall and excess rainfall. The grass species used were the novel hybrid species Festulolium cv Prior (Fest_1), Festulolium Bx511 (Fest_2) and a conventional mixture of Lolium perenne and Festuca rubra (Conv). Monocultures and mixtures of these species were studied. Plant traits pertinent to control of soil erosion by water were measured. Above ground traits included plant height, percentage ground cover, above ground biomass, stem diameter, stem area density and number of tillers. Below ground traits included total root length, root total surface area, below ground biomass, root diameter and % fine roots ≤0.25 mm. For summer conditions, the species treatments which had the highest overall soil erosion mitigation potential were Conv, Fest_1 + 2 + Conv and Fest_2. For autumn conditions, the best treatments were Fest_1 + 2, Fest_1 + 2 + Conv and Conv. The Fest 1 + 2 + conv had more desirable traits for erosion control than mono Festulolium treatments for the autumn conditions. The conventional mixture had more desirable traits for erosion control than mono Festulolium treatments in both climate scenarios. The results indicate that the trait‐based ranking approach utilised in this study can be used to inform rapid screening of candidate grass species for soil erosion control

Importance of small fishes and invasive crayfish in otter Lutra lutra diet in an English chalk stream

The diet composition of the European otter Lutra lutra was assessed using spraint analysis in the Hampshire Avon, a lowland chalk stream in Southern England, over an 18 month period. Small cyprinid fishes were the main prey item taken in all seasons, with bullhead Cottus gobio and stone loach Barbatula barbatula also important; there were relatively few larger fishes of interest to fisheries found. There were significant seasonal differences in diet composition by season, with signal crayfish Pacifastacus leniusculus only being prominent prey items in warmer months and amphibians in winter, revealing that non-fish resources were seasonally important dietary components. Reconstructed body lengths of prey revealed the only species present in diet >350 mm was pike Esox lucius. These dietary data thus provide important information for informing conservation conflicts between otters and fishery interest

Partnership for Research on Ebola VACcination (PREVAC): protocol of a randomized, double-blind, placebo-controlled phase 2 clinical trial evaluating three vaccine strategies against Ebola in healthy volunteers in four West African countries

International audienceAbstract Introduction The Ebola virus disease (EVD) outbreak in 2014–2016 in West Africa was the largest on record and provided an opportunity for large clinical trials and accelerated efforts to develop an effective and safe preventative vaccine. Multiple questions regarding the safety, immunogenicity, and efficacy of EVD vaccines remain unanswered. To address these gaps in the evidence base, the Partnership for Research on Ebola Vaccines (PREVAC) trial was designed. This paper describes the design, methods, and baseline results of the PREVAC trial and discusses challenges that led to different protocol amendments. Methods This is a randomized, double-blind, placebo-controlled phase 2 clinical trial of three vaccine strategies against the Ebola virus in healthy volunteers 1 year of age and above. The three vaccine strategies being studied are the rVSVΔG-ZEBOV-GP vaccine, with and without a booster dose at 56 days, and the Ad26.ZEBOV,MVA-FN-Filo vaccine regimen with Ad26.ZEBOV given as the first dose and the MVA-FN-Filo vaccination given 56 days later. There have been 4 versions of the protocol with those enrolled in Version 4.0 comprising the primary analysis cohort. The primary endpoint is based on the antibody titer against the Ebola virus surface glycoprotein measured 12 months following the final injection. Results From April 2017 to December 2018, a total of 5002 volunteers were screened and 4789 enrolled. Participants were enrolled at 6 sites in four countries (Guinea, Liberia, Sierra Leone, and Mali). Of the 4789 participants, 2560 (53%) were adults and 2229 (47%) were children. Those < 18 years of age included 549 (12%) aged 1 to 4 years, 750 (16%) 5 to 11 years, and 930 (19%) aged 12–17 years. At baseline, the median (25th, 75th percentile) antibody titer to Ebola virus glycoprotein for 1090 participants was 72 (50, 116) EU/mL. Discussion The PREVAC trial is evaluating—placebo-controlled—two promising Ebola candidate vaccines in advanced stages of development. The results will address unanswered questions related to short- and long-term safety and immunogenicity for three vaccine strategies in adults and children. Trial registration ClinicalTrials.gov NCT02876328 . Registered on 23 August 2016

Science with the Cherenkov Telescope Array

213 pages, including references and glossary. Version 2: credits and references updated, some figures updated, and author list updatedInternational audienceThe Cherenkov Telescope Array, CTA, will be the major global observatory for very high energy gamma-ray astronomy over the next decade and beyond. The scientific potential of CTA is extremely broad: from understanding the role of relativistic cosmic particles to the search for dark matter. CTA is an explorer of the extreme universe, probing environments from the immediate neighbourhood of black holes to cosmic voids on the largest scales. Covering a huge range in photon energy from 20 GeV to 300 TeV, CTA will improve on all aspects of performance with respect to current instruments. The observatory will operate arrays on sites in both hemispheres to provide full sky coverage and will hence maximize the potential for the rarest phenomena such as very nearby supernovae, gamma-ray bursts or gravitational wave transients. With 99 telescopes on the southern site and 19 telescopes on the northern site, flexible operation will be possible, with sub-arrays available for specific tasks. CTA will have important synergies with many of the new generation of major astronomical and astroparticle observatories. Multi-wavelength and multi-messenger approaches combining CTA data with those from other instruments will lead to a deeper understanding of the broad-band non-thermal properties of target sources. The CTA Observatory will be operated as an open, proposal-driven observatory, with all data available on a public archive after a pre-defined proprietary period. Scientists from institutions worldwide have combined together to form the CTA Consortium. This Consortium has prepared a proposal for a Core Programme of highly motivated observations. The programme, encompassing approximately 40% of the available observing time over the first ten years of CTA operation, is made up of individual Key Science Projects (KSPs), which are presented in this document

Effect of general anaesthesia on functional outcome in patients with anterior circulation ischaemic stroke having endovascular thrombectomy versus standard care: a meta-analysis of individual patient data

Background: General anaesthesia (GA) during endovascular thrombectomy has been associated with worse patient outcomes in observational studies compared with patients treated without GA. We assessed functional outcome in ischaemic stroke patients with large vessel anterior circulation occlusion undergoing endovascular thrombectomy under GA, versus thrombectomy not under GA (with or without sedation) versus standard care (ie, no thrombectomy), stratified by the use of GA versus standard care. Methods: For this meta-analysis, patient-level data were pooled from all patients included in randomised trials in PuMed published between Jan 1, 2010, and May 31, 2017, that compared endovascular thrombectomy predominantly done with stent retrievers with standard care in anterior circulation ischaemic stroke patients (HERMES Collaboration). The primary outcome was functional outcome assessed by ordinal analysis of the modified Rankin scale (mRS) at 90 days in the GA and non-GA subgroups of patients treated with endovascular therapy versus those patients treated with standard care, adjusted for baseline prognostic variables. To account for between-trial variance we used mixed-effects modelling with a random effect for trials incorporated in all models. Bias was assessed using the Cochrane method. The meta-analysis was prospectively designed, but not registered. Findings: Seven trials were identified by our search; of 1764 patients included in these trials, 871 were allocated to endovascular thrombectomy and 893 were assigned standard care. After exclusion of 74 patients (72 did not undergo the procedure and two had missing data on anaesthetic strategy), 236 (30%) of 797 patients who had endovascular procedures were treated under GA. At baseline, patients receiving GA were younger and had a shorter delay between stroke onset and randomisation but they had similar pre-treatment clinical severity compared with patients who did not have GA. Endovascular thrombectomy improved functional outcome at 3 months both in patients who had GA (adjusted common odds ratio (cOR) 1·52, 95% CI 1·09–2·11, p=0·014) and in those who did not have GA (adjusted cOR 2·33, 95% CI 1·75–3·10, p&lt;0·0001) versus standard care. However, outcomes were significantly better for patients who did not receive GA versus those who received GA (covariate-adjusted cOR 1·53, 95% CI 1·14–2·04, p=0·0044). The risk of bias and variability between studies was assessed to be low. Interpretation: Worse outcomes after endovascular thrombectomy were associated with GA, after adjustment for baseline prognostic variables. These data support avoidance of GA whenever possible. The procedure did, however, remain effective versus standard care in patients treated under GA, indicating that treatment should not be withheld in those who require anaesthesia for medical reasons