Methane, carbon dioxide and nitrous oxide fluxes from a temperate salt marsh: grazing management does not alter global warming potential

Soil greenhouse gas emissions from cattle grazed and un-grazed temperate upper salt marsh were measured using dark static chambers, monthly for one year. Below-ground gas sampling tubes were also used to measure soil methane (CH4) concentrations. CH4 efflux from grazed and un-grazed salt marsh did not differ significantly although grazing did lead to ‘hotspots’ of underground CH4 (up to 6% of total air volume) and CH4 efflux (peak of 9 mg m−2 h−1) significantly linked to high soil moisture content, low soil temperatures and the presence of Juncus gerardii. Carbon dioxide (CO2) efflux was greater from the un-grazed marsh (mean of 420 mg m−2 h−1) than the grazed marsh (mean of 333 mg m−2 h−1) throughout most of the year and was positively correlated with the deeper water table and greater soil temperatures. Grazing was not a significant predictor of nitrous oxide (N2O) soil emissions. Global Warming Potential (GWP; over 100 years), calculated from mean yearly chamber fluxes for CH4 and CO2, did not differ significantly with grazing treatment. Seasonal variation in the key drivers of soil greenhouse gas efflux; soil temperature, moisture and water table, plus the presence or absence of aerenchymatous plants such as J. gerardii were more important to the magnitude of greenhouse gas emissions than grazing management per se

Electrocortical components of anticipation and consumption in a monetary incentive delay task

In order to improve our understanding of the components that reflect functionally important processes during reward anticipation and consumption, we used principle components analyses (PCA) to separate and quantify averaged ERP data obtained from each stage of a modified monetary incentive delay (MID) task. Although a small number of recent ERP studies have reported that reward and loss cues potentiate ERPs during anticipation, action preparation, and consummatory stages of reward processing, these findings are inconsistent due to temporal and spatial overlap between the relevant electrophysiological components. Our results show three components following cue presentation are sensitive to incentive cues (N1, P3a, P3b). In contrast to previous research, reward‐related enhancement occurred only in the P3b, with earlier components more sensitive to break‐even and loss cues. During feedback anticipation, we observed a lateralized centroparietal negativity that was sensitive to response hand but not cue type. We also show that use of PCA on ERPs reflecting reward consumption successfully separates the reward positivity from the independently modulated feedback‐P3. Last, we observe for the first time a new reward consumption component: a late negativity distributed over the left frontal pole. This component appears to be sensitive to response hand, especially in the context of monetary gain. These results illustrate that the time course and sensitivities of electrophysiological activity that follows incentive cues do not follow a simple heuristic in which reward incentive cues produce enhanced activity at all stages and substages

Establishing international best practice principles for impact assessment teaching and training

Best Practice Principles for Impact Assessment (IA) Teaching and Training were developed for the International Association for Impact Assessment (IAIA). Research conducted throughout 2018 and 2019 encompassed seven iterative steps: an initial practitioners workshop; comprehensive review of 40 years of literature on teaching IA; initial survey of teachers and trainers; follow-up interviews; development of draft set of principles; final survey of the importance of the draft principles to university teachers and professional development trainers in IA; and a final workshop at IAIA19. The resulting principles are grouped in relation to content (what is taught), pedagogy (how content is taught) and skills development. From 29 draft principles, those identified as ‘Extremely Important’ or Very Important’ (28 in total) in the final survey were included in the Principles published by IAIA. Differences in relative importance of the principles are apparent between teachers and trainers, reflecting their different teaching contexts and objectives. It is hoped that the principles can contribute to more consistent and more effective IA education, contributing in turn to improved IA practice

Grossly delayed massive subcutaneous emphysema following laparoscopic left hemicolectomy: A case report

AbstractINTRODUCTIONSurgical emphysema is a known early complication of laparoscopic surgery, common during upper gastrointestinal and gynaecological surgery; the authors present the first case of delayed subcutaneous emphysema following a laparoscopic left hemicolectomy.PRESENTATION OF CASEA 52-year-old woman underwent a laparoscopic left hemicolectomy for a sigmoid malignancy; on the third post-operative day after an uneventful procedure, she developed a massive surgical emphysema involving her face, neck and chest with associated pneumoperitoneum but without any evidence of pneumothorax. A gastrograffin enema ruled out an anastomotic leak. Apart from a borderline tachycardia, mildly low saturations and an area of erythema in her right flank, she was totally asymptomatic. The emphysema resolved spontaneously around the 6th post-operative day.DISCUSSIONMassive subcutaneous surgical emphysema after laparoscopic colorectal surgery is a rare complication and can me managed conservatively with a good outcome.CONCLUSIONTo our knowledge, this represents the first case of delayed massive surgical emphysema following colorectal surgery, the aetiology of which has still not been clearly explained, after exclusion of the most common causes

Assessment of vapour chamber heat spreader implementation for avionic module thermal management

Thermal management of aircraft heat loads is quickly becoming a limiting factor of vehicle performance and reliability. This paper details improvements in forced-convection cooled avionic module heat removal efficiency with the implementation of two-phase high thermal conductivity Vapour Chamber Heat Spreaders (VCHS). A bespoke test rig provides experimental thermal comparisons of an aluminium and embedded VCHS avionic heat exchanger. The experimental results validate a numerical thermal resistance network, which is utilised to simulate more representative avionic chassis geometries. The VCHS dramatically reduces thermal variation in circuit card and avionic heat exchanger exhaust temperatures. Increased isothermalisation of the heat exchanger greatly increases effective heat transfer area in comparison to a traditional aluminium chassis. The VCHS acts as a very effective thermal buffer between the avionic circuit cards and coolant airflow, allowing a more predictable avionic thermal behaviour irrespective of circuit card architecture. The improved heat rejection capability allows either a substantial increase in avionic growth capacity (increased power output for a fixed exhaust temperature) or a substantial reduction in mass flow rate (reduced demand on vehicle thermal management system). An avionic growth capacity of up to 58% is achieved with representative thermal loading conditions

Experimental assessment of vapour chamber heat spreader implementation in avionic cooling

Avionic thermal management is quickly becoming the limiting factor of aircraft performance and reliability, particularly prevalent with ageing airframes. While the increasing power density of avionic components requires a greater heat removal capacity for a given geometric module size, supplementary generation of cooling airflow is detrimental to engine and aircraft performance. This paper looks at improving the heat removal efficiency of forced convection cooled avionic modules by reducing the thermal resistance between the avionic component and module heat exchanger. The implementation of two-phase high thermal conductivity materials, such as Vapour Chamber Heat Spreaders (VCHS), embedded within the avionic module chassis act to improve heat exchanger isothermalisation, improving the effective heat transfer area. A bespoke test rig has been manufactured to experimentally compare a pure aluminium and embedded VCHS avionic chassis for heat removal capability. When considering a single circuit card, a direct mass flow rate reduction of between 22% and 65% is achieved with embedded VCHS over a pure aluminium chassis. Base plate isothermalisation is improved by 9%, generating a reduction in component temperature of 8% to 12%. As the number of heat sources increase, the performance improvements decrease. When testing with three circuit cards mass flow rate savings are reduced to between 14% and 26%. The concluding performance characteristic of the embedded VCHS avionic base plate is the insensitivity to the way thermal energy is coupled to it. Across all testing, the localised heat removal was never further than 3.5% from the averaged plate performance

The value of carbon sequestration and storage in coastal habitats

Coastal margin habitats are globally significant in terms of their capacity to sequester and store carbon, but their continuing decline, due to environmental change and human land use decisions, is reducing their capacity to provide this ecosystem service. In this paper the UK is used as a case study area to develop methodologies to quantify and value the ecosystem service of blue carbon sequestration and storage in coastal margin habitats. Changes in UK coastal habitat area between 1900 and 2060 are documented, the long term stocks of carbon stored by these habitats are calculated, and the capacity of these habitats to sequester CO2 is detailed. Changes in value of the carbon sequestration service of coastal habitats are then projected for 2000–2060 under two scenarios, the maintenance of the current state of the habitat and the continuation of current trends of habitat loss. If coastal habitats are maintained at their current extent, their sequestration capacity over the period 2000–2060 is valued to be in the region of £1 billion UK sterling (3.5% discount rate). However, if current trends of habitat loss continue, the capacity of the coastal habitats both to sequester and store CO2 will be significantly reduced, with a reduction in value of around £0.25 billion UK sterling (2000–2060; 3.5% discount rate). If loss-trends due to sea level rise or land reclamation worsen, this loss in value will be greater. This case study provides valuable site specific information, but also highlights global issues regarding the quantification and valuation of carbon sequestration and storage. Whilst our ability to value ecosystem services is improving, considerable uncertainty remains. If such ecosystem valuations are to be incorporated with confidence into national and global policy and legislative frameworks, it is necessary to address this uncertainty. Recommendations to achieve this are outlined