Mechanical properties of calvarial bones in a mouse model for craniosynostosis

The mammalian cranial vault largely consists of five flat bones that are joined together along their edges by soft fibrous tissues called sutures. Premature closure of the cranial sutures, craniosynostosis, can lead to serious clinical pathology unless there is surgical intervention. Research into the genetic basis of the disease has led to the development of various animal models that display this condition, e.g. mutant type Fgfr2C342Y/+ mice which display early fusion of the coronal suture (joining the parietal and frontal bones). However, whether the biomechanical properties of the mutant and wild type bones are affected has not been investigated before. Therefore, nanoindentation was used to compare the elastic modulus of cranial bone and sutures in wild type (WT) and Fgfr2C342Y/+mutant type (MT) mice during their postnatal development. Further, the variations in properties with indentation position and plane were assessed. No difference was observed in the elastic modulus of parietal bone between the WT and MT mice at postnatal (P) day 10 and 20. However, the modulus of frontal bone in the MT group was lower than the WT group at both P10 (1.39±0.30 vs. 5.32±0.68 GPa; p<0.05) and P20 (5.57±0.33 vs. 7.14±0.79 GPa; p<0.05). A wide range of values was measured along the coronal sutures for both the WT and MT samples, with no significant difference between the two groups. Findings of this study suggest that the inherent mechanical properties of the frontal bone in the mutant mice were different to the wild type mice from the same genetic background. These differences may reflect variations in the degree of biomechanical adaptation during skull growth, which could have implications for the surgical management of craniosynostosis patients

Catchment subsurface water storage, mixing and flowpaths: implications for land cover change as a natural flood management strategy

Efforts are increasing globally to harness the potential of forests to alter catchment water runoff and storage dynamics as a ‘natural flood management’ (NFM) strategy, particularly given a projected rise in the frequency and severity of floods with climate change. Despite decades of research on forest hydrology, knowledge of how forests and land use control catchment runoff is still limited, especially in relation to important, though less investigated, subsurface runoff processes. This PhD research aimed to examine how forest cover interacts with soils and geology to influence runoff pathways at different spatial and temporal scales, focusing on the 67 km2 Eddleston Water NFM pilot site in the Scottish Borders. At the catchment scale, isotopic (2H and 18O)and geochemical tracers (Acid Neutralising Capacity (ANC)), conductivity and pH) were used to investigate whether forest cover is a significant control on water storage and mixing over seasonal and storm event timescales. At the hillslope scale, dense subsurface monitoring (soil moisture, groundwater and time-lapse electrical resistivity tomography (ERT)) compared improved grassland to an across-slope forest strip, similar to those promoted in NFM schemes to control runoff, to reveal water storage potential in soil underneath the forest and the downslope extent of any impacts on subsurface hydrological dynamics. The results revealed complex interactions between land cover and runoff processes at different scales. At the catchment scale, soil type and superficial geology were found to be more dominant controls on catchment storage over seasonal timescales, with land cover playing a secondary role. Dynamic storage estimates for headwater catchments underlain predominantly by glacial till were low, ranging from ~16 mm to 46 mm, and were correlated with low mean transit times, ranging from ~130 to ~210 days. There were no differences in these estimates, within the bounds of error, between catchments with up to 90% forest cover and those with much lower cover (<50%). However, there were significant differences compared to steeper catchments with low glacial till cover. In these catchments dynamic storage estimates ranged from ~160 mm to~200 mm, and were correlated with high mean transit times, ranging from ~320 to~370 days. At the storm event timescale, and comparing two adjacent catchments with similar superficial geology and soils but differences in land cover, forest cover reduced the event water runoff fraction for four high flow events. The fraction of event water runoff at peak discharge during the largest event monitored was 0.37 for the forested catchment but 0.54 for the adjacent partially forested catchment. A third catchment, with minimal glacial till and low forest cover, demonstrated very different dynamics, with much lower runoff ratios for all events, higher groundwater fractions (0.21-0.55 at peak), and ‘double-peak’ hydrographs, illustrating the impacts of geology on runoff processes. Similar relative differences in runoff fractions were found between catchments across the three winter events, with differences between storms greater than differences between catchments. These findings suggest that while catchment characteristics mediate event responses, the characteristics of the event(rainfall depth, intensity and antecedent conditions) may dominate responses, though it was not possible to disaggregate the different event characteristics with this dataset. The hillslope scale work identified significant differences in subsurface moisture dynamics underneath the forest strip over seasonal timescales: drying of the forest soils was greater, and extended deeper and for longer into the autumn compared to the adjacent grassland soils. Water table levels were also persistently lower in the forest and the forest soils responded less frequently to storm events. Downslope of the forest, soil moisture dynamics were similar to those in other grassland areas and no significant differences were observed beyond 15 m downslope, suggesting minimal impact of the forest at shallow depths downslope. The depth to the water table was greater downslope of the forest compared to other grassland areas, but during the wettest conditions there was evidence of upslope-downslope water table connectivity beneath the forest. The results indicate that forest strips provide only limited additional subsurface storage of rainfall inputs in flood events after dry conditions in this temperate catchment setting. In summary, the research results show that while forests have some seasonal impacts on subsurface moisture dynamics, soil type and underlying superficial geology are primary controls on catchment storage and mixing in temperate upland environments, suggesting limited impacts of changing land use. At storm event timescales increased forest cover has some impact on reducing the amount of event water runoff, but event characteristics are a more dominant control, so forest cover alone is unlikely to lead to significant reductions in peak flows during large flood events. Strategically placed forest cover, such as field boundary planting on hillslopes has some impacts on subsurface moisture dynamics but the effects are spatially limited and not present in winter periods. The processes leading to these findings appear to be similar at the catchment and hillslope scales. From an NFM policy perspective the findings suggest that while tree planting is not a flood management panacea, it may have benefits in certain situations, as well as significant co-benefits. This implies a need for a change in emphasis within flood risk management policy, which ‘mainstreams’ tree planting as a flood risk strategy into wider policy processes to create multifunctional landscapes. There are still many unknowns about the impacts of land cover on hydrological processes, particularly in the subsurface, and there is a need for enhanced research on these processes. This will also help to reduce some of the large uncertainties surrounding the impacts of NFM, which remain one of the key barriers to its wider implementation

Land use partnerships for addressing climate change: What are they, why use them, and how do they work?

Policy brief produced to inform the Scottish Government's Regional Land Use Partnership programme.Reducing greenhouse gas emissions and achieving climate change adaptation objectives in the land sector will rely on effective collaboration bridging scales and sectors. Many approaches to ‘partnership’ working have been developed in the sector, working at different scales and focussed on a range of issues. Scotland has committed to the development of Regional Land Use Partnerships (RLUPs) to help deliver a more integrated approach to land use change and management, and meet its target of net zero by 2045. Stakeholders have different expectations about what RLUPs can deliver and how they might function. Success will rely in part on there being a clear vision for how they work. This brief explores how existing land use partnerships work and the learning they provide for how RLUPs might be designed to meet their multiple objectives

The Impact of Quark/Gluon Tagging on Searches for Dark Matter in Dijet Event Data with the ATLAS Detector

Differentiating between quark-and-gluon initiated events can be a useful tool for increasing the signal to noise ratio in searches of new physics. This thesis presents an analysis of the impact of quark-gluon tagging on the dijet invariant mass spectrum. Monte Carlo simulated data were compared with the ATLAS data from Run-2 of the LHC at 13 TeV. Truth information from the simulations was used to make a simple quark-gluon tagger based on the sum of the multiplicities of the two leading jets in a dijet event. A range of gluon-gluon selection efficiencies were applied to a H′ signal and 95% CL upper limits were found and compared between tagged and untagged samples. No improvements in the H′ upper limits were observed for any tested efficiency

Perspectives of Intensive Care patients and family members on competencies for Advanced Intensive Care nurses in Europe

BackgroundOne output from the International Nursing Advanced Competency-based Training for Intensive Care (INACTIC) collaboration is a set of core competencies for advanced practice Intensive Care Unit (ICU) nurses across Europe. Some European countries, such as the UK, have identified such competencies, however, these advanced practice roles are rarely practiced across the rest of Europe. The INACTIC competencies were developed with an expert panel of 184 ICU nurses from 20 countries. It is also important to examine what patients and relatives with experience of intensive care felt about these competencies. AimTo examine the views of recovered ICU patients and relatives regarding the INACTIC competencies.MethodsThree patient and relative focus groups were conducted in England (n=5), Scotland (n=4) and Greece (n=4) to discuss a lay version of the INACTIC competencies. Discussions were open ended, followed a topic guide, recorded and transcribed verbatim. Analysis followed a conventional thematic approach, with the findings discussed iteratively among the authors.ResultsThe feedback from across the focus groups resulted in three themes: 1) the importance of nurses being empowered to advocate for the patient; 2) the centrality of communication; and, 3) the impact of variability in ICU practices. There was a notable difference with the Greek focus group; because of restricted family visiting policies, relatives did not feel encouraged to participate in patient care.ConclusionsThe perspectives of patients and relatives largely aligned with the consensus of the INACTIC expert panel. Local differences in ICU experience highlight the changes that some ICUs would need to make for the INACTIC competencies to be embedded

How does geological heterogeneity control floodplain groundwater dynamics?

Upland floodplains provide an important function in regulating river flows and controlling the coupling of hillslope runoff with rivers. A floodplain in an upland area of the River Tweed catchment, Scotland, was characterised using geophysics, 3D geological mapping, hydrogeological testing and geochemical sampling, and monitored from September 2011 to February 2013 for variations in groundwater levels, river stage, soil moisture and meteorological parameters, including a period of nine months of exceptionally high rainfall. The floodplain contains an unconsolidated, permeable alluvial and glaciofluvial aquifer 8 to 15 m thick, with transmissivity 50 to 1000 m2/d, which is coupled to the hillslope by permeable solifluction deposits. The floodplain aquifer is a significant store of, and conduit for, catchment water. It gains recharge from the river and the adjacent hillslope, transmitting groundwater downstream and acting as a buffer to restrict water flowing from the hillslope from directly entering the river. Floodplain groundwater level fluctuations are driven primarily by changes in river level and the propagation of pressure waves through the floodplain aquifer. There is significant lateral variation in floodplain groundwater response. Most of the floodplain aquifer is hydraulically connected to the river, but groundwater at the edge of the floodplain is strongly controlled by hillslope sub-surface flow. The geological structure and lithology of the hillslope-floodplain transition is an important hydrological control. It can enhance the influence of subsurface hillslope runoff to the floodplain, which has implications for runoff modelling, flood prevention interventions on hillslopes aimed at reducing runoff, and development at floodplain edges. Vertical heterogeneity in hydrological properties within the floodplain aquifer alters hydrological response, causing different depths of the floodplain to respond differently to hillslope and river inputs. These vertical variations need to be better taken into account in floodplain and hillslope-floodplain studies. This research demonstrates the importance of understanding the 3D geology and hydrogeology of floodplains in order to advance catchment research and effective flood management measures

Land cover influence on catchment scale subsurface water storage investigated by multiple methods:Implications for UK Natural Flood Management

Study region: United Kingdom (UK). Study Focus: ‘Natural flood management’ (NFM) schemes manipulating land use and other catchment features to control runoff are increasingly promoted across the UK. Catchment water storage and mixing processes influence runoff, but our understanding of the effects of land cover change on these processes is still limited. This study combined hydrometric, isotopic and geochemical measurements to investigate land cover versus potential topographic, soil and geological controls. It compared storage-discharge dynamics in nine nested catchments within a 67 km2 managed upland catchment in southern Scotland. Storage and mixing dynamics were characterised from hydrometric data using recession analysis and from isotopic data using mean transit time and young water fraction estimates. To give information on water sources, groundwater fraction was estimated from end member mixing analysis based on acid neutralising capacity.New hydrological insights: The analysis showed low but variable sub-catchment scale dynamic storage (16–200 mm), mean transit times (134–370 days) and groundwater fractions (0.20–0.52 of annual stream runoff). Soil hydraulic conductivity was most significantly positively correlated with storage and mixing measures, whilst percentage forest cover was inversely correlated. Any effects of forest cover on increasing catchment infiltration and storage are masked by soil hydraulic properties even in the most responsive catchments. This highlights the importance of understanding dominant controls on catchment storage when using tree planting as a flood management strategy