15 results on '"Clement, Emilie"'
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2. Assessing the impact of peat erosion on growing season CO2 fluxes by comparing erosional peat pans and surrounding vegetated haggs
- Author
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Gatis, Naomi, Benaud, Pia, Ashe, Josie, Luscombe, David J., Grand-Clement, Emilie, Hartley, Iain P., Anderson, Karen, and Brazier, Richard E.
- Published
- 2019
- Full Text
- View/download PDF
3. How does drainage alter the hydrology of shallow degraded peatlands across multiple spatial scales?
- Author
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Luscombe, David J., Anderson, Karen, Grand-Clement, Emilie, Gatis, Naomi, Ashe, Josie, Benaud, Pia, Smith, David, and Brazier, Richard E.
- Published
- 2016
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4. Evaluating ecosystem goods and services after restoration of marginal upland peatlands in South-West England
- Author
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Grand-Clement, Emilie, Anderson, Karen, Smith, David, Luscombe, David, Gatis, Naomi, Ross, Martin, and Brazier, Richard E.
- Published
- 2013
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5. The effect of drainage ditches on vegetation diversity and CO2 fluxes in a Molinia caerulea-dominated peatland
- Author
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Gatis, Naomi, Luscombe, David J., Grand-Clement, Emilie, Hartley, Iain P., Anderson, Karen, Smith, David, and Brazier, Richard E.
- Published
- 2016
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- View/download PDF
6. What does airborne LiDAR really measure in upland ecosystems?
- Author
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Luscombe, David J., Anderson, Karen, Gatis, Naomi, Wetherelt, Andrew, Grand-Clement, Emilie, and Brazier, Richard E.
- Published
- 2015
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7. Assessing the impact of peat erosion on growing season CO2 fluxes by comparing erosional peat pans and surrounding vegetated haggs.
- Author
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Gatis, Naomi, Benaud, Pia, Ashe, Josie, Luscombe, David J., Grand-Clement, Emilie, Hartley, Iain P., Anderson, Karen, and Brazier, Richard E.
- Subjects
GROWING season ,PEAT ,ATMOSPHERIC carbon dioxide ,HETEROTROPHIC respiration ,DECISION making ,WATER table - Abstract
Peatlands are recognised as an important but vulnerable ecological resource. Understanding the effects of existing damage, in this case erosion, enables more informed land management decisions to be made. Over the growing seasons of 2013 and 2014 photosynthesis and ecosystem respiration were measured using closed chamber techniques within vegetated haggs and erosional peat pans in Dartmoor National Park, southwest England. Below-ground total and heterotrophic respiration were measured and autotrophic respiration estimated from the vegetated haggs. The mean water table was significantly higher in the peat pans than in the vegetated haggs; because of this, and the switching from submerged to dry peat, there were differences in vegetation composition, photosynthesis and ecosystem respiration. In the peat pans photosynthetic CO
2 uptake and ecosystem respiration were greater than in the vegetated haggs and strongly dependent on the depth to water table (r2 > 0.78, p < 0.001). Whilst in the vegetated haggs, photosynthesis and ecosystem respiration had the strongest relationships with normalised difference vegetation index (NDVI) (r2 = 0.82, p < 0.001) and soil temperature at 15 cm depth (r2 = 0.77, p = 0.001). Autotrophic and total below-ground respiration in the vegetated haggs varied with soil temperature; heterotrophic respiration increased as water tables fell. An empirically derived net ecosystem model estimated that over the two growing seasons both the vegetated haggs (29 and 20 gC m−2 ; 95% confidence intervals of − 570 to 762 and − 873 to 1105 gC m−2 ) and the peat pans (7 and 8 gC m−2 ; 95% confidence intervals of − 147 to 465 and − 136 to 436 gC m−2 ) were most likely net CO2 sources. This study suggests that not only the visibly degraded bare peat pans but also the surrounding vegetated haggs are losing carbon to the atmosphere, particularly during warmer and drier conditions, highlighting a need for ecohydrological restoration. [ABSTRACT FROM AUTHOR]- Published
- 2019
- Full Text
- View/download PDF
8. Skp2-dependent reactivation of AKT drives resistance to PI3K inhibitors.
- Author
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Clement, Emilie, Inuzuka, Hiroyuki, Nihira, Naoe T., Wei, Wenyi, and Toker, Alex
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PROTEIN kinase B ,CELLULAR signal transduction ,GENETICS of breast cancer ,PHOSPHOINOSITIDE-dependent kinase-1 ,GENETIC mutation ,GENE expression - Abstract
The PI3K-AKT kinase signaling pathway is frequently deregulated in human cancers, particularly breast cancer, where amplification and somatic mutations of PIK3CA occur with high frequency in patients. Numerous small-molecule inhibitors targeting both PI3K and AKT are under clinical evaluation, but dose-limiting toxicities and the emergence of resistance limit therapeutic efficacy. Various resistance mechanisms to PI3K inhibitors have been identified, including de novo mutations, feedback activation of AKT, or cross-talk pathways. We found a previously unknown resistance mechanism to PI3K pathway inhibition that results in AKT rebound activation. In a subset of triple-negative breast cancer cell lines, treatment with a PI3K inhibitor or depletion of PIK3CA expression ultimately promoted AKT reactivation in a manner dependent on the E3 ubiquitin ligase Skp2, the kinases IGF-1R (insulin-like growth factor 1 receptor) and PDK-1 (phosphoinositide-dependent kinase-1), and the cell growth and metabolism-regulating complex mTORC2 (mechanistic target of rapamycin complex 2), but was independent of PI3K activity or PIP3 production. Resistance to PI3K inhibitors correlated with the increased abundance of Skp2, ubiquitylation of AKT, cell proliferation in culture, and xenograft tumor growth in mice. These findings reveal a ubiquitin signaling feedback mechanism by which PI3K inhibitor resistance may emerge in aggressive breast cancer cells. [ABSTRACT FROM AUTHOR]
- Published
- 2018
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9. Evaluating MODIS vegetation products using digital images for quantifying local peatland CO2 gas fluxes.
- Author
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Gatis, Naomi, Anderson, Karen, Grand-Clement, Emilie, Luscombe, David J., Hartley, Iain P., Smith, David, and Brazier, Richard E.
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- 2017
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10. The effect of drainage ditches on vegetation diversity and CO2 fluxes in a Molinia caerulea-dominated peatland.
- Author
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Gatis, Naomi, Luscombe, David J., Grand‐Clement, Emilie, Hartley, Iain P., Anderson, Karen, Smith, David, and Brazier, Richard E.
- Subjects
DRAINAGE ,PLANT diversity ,GROWING season ,PRIMARY productivity (Biology) ,CARBON dioxide ,PEATLAND ecology ,WATER table - Abstract
Peatlands are recognized as important carbon stores; despite this, many have been drained for agricultural improvement. Drainage has been shown to lower water tables and alter vegetation composition, modifying primary productivity and decomposition, potentially initiating peat loss. To quantify CO
2 fluxes across whole landscapes, it is vital to understand how vegetation composition and CO2 fluxes vary spatially in response to the pattern of drainage features. However, Molinia caerulea-dominated peatlands are poorly understood despite their widespread extent. Photosynthesis (PG600 ) and ecosystem respiration (REco ) were modelled (12 °C, 600 µmol photons m−2 s−1 , greenness excess index of 60) using empirically derived parameters based on closed-chamber measurements collected over a growing season. Partitioned below-ground fluxes were also collected. Plots were arranged ⅛, ¼ and ½ the distance between adjacent ditches in two catchments located in Exmoor National Park, southwest England. Water table depths were deepest closest to the ditch and non-significantly ( p = 0·197) shallower further away. Non- Molinia species coverage and the Simpson diversity index significantly decreased with water table depth ( p < 0·024) and increased non-significantly ( p < 0·083) away from the ditch. No CO2 fluxes showed significant spatial distribution in response to drainage ditches, arguably due to insignificant spatial distribution of water tables and vegetation composition. Whilst REco showed no significant spatial variation, PG600 varied significantly between sites ( p = 0·012), thereby controlling the spatial distribution of net ecosystem exchange between sites. As PG600 significantly co-varied with water table depths ( p = 0·034), determining the spatial distribution of water table depths may enable CO2 fluxes to be estimated across M. caerulea-dominated landscapes. © 2015 The Authors. Ecohydrology published by John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]- Published
- 2016
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11. Using airborne thermal imaging data to measure near-surface hydrology in upland ecosystems.
- Author
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Luscombe, David J., Anderson, Karen, Gatis, Naomi, Grand ‐ Clement, Emilie, and Brazier, Richard E.
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UPLANDS ,ECOSYSTEMS ,PEAT industry ,THERMOGRAPHY ,EMISSIVITY - Abstract
Upland ecosystems are recognized for their importance in providing valuable ecosystem services including water storage, water supply and flood attenuation alongside carbon storage and biodiversity. The UK contains 10-15% of the global resource of upland blanket peatlands, the hydrology and ecology of which are highly sensitive to external anthropogenic and climatic forcing. In particular, drainage of these landscapes for agricultural intensification and peat extraction has resulted in often unquantified damage to the peatland hydrology, and little is understood about the spatially distributed impacts of these practices on near-surface wetness. This paper develops new techniques to extract spatial data describing the near-surface wetness and hydrological behaviour of drained blanket peatlands using airborne thermal imaging data and airborne Light Detection and Ranging (LiDAR) data. The relative thermal emissivity (Ɛ
r ) of the ground surface is mapped and used as a proxy for near-surface wetness. The results show how moorland drainage and land surface structure have an impact on airborne measurements of thermal emissivity. Specifically, we show that information on land surface structure derived from LiDAR can help normalize signals in thermal emissivity data to improve description of hydrological condition across a test catchment in Exmoor, UK. An in situ field hydrological survey was used to validate these findings. We discuss how such data could be used to describe the spatially distributed nature of near-surface water resources, to optimize catchment management schemes and to deliver improved understanding of the drivers of hydrological change in analogous ecosystems. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]- Published
- 2015
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12. Continental-scale measurement of the soil organic carbon pool with climatic, edaphic, and biotic controls.
- Author
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Wynn, Jonathan G., Bird, Michael I., Vellen, Lins, Grand-Clement, Emilie, Carter, John, and Berry, Sandra L.
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SOIL testing ,SOIL texture ,SOIL science ,TREES ,GRASSES ,WATER supply - Abstract
We present data on soil organic carbon (SOC) inventory for 7050 soil cores collected from a wide range of environmental conditions throughout Australia. The data set is stratified over the spatial distribution of trees and grass to account for variability of Soc inventory with vegetation distribution. We model controls on SOC inventory using an index of water availability and mean annual temperature to represent the climatic control on the rate of C input into the SOC pool and decomposition of SOC, in addition to the fraction of soil particles <63 μm in diameter as a measure of textural control on SOC stabilization. soc inventories in the top 30 cm of soil increase from 35 mg/cm² in the driest regions to a modeled plateau with respect to a threshold of water availability at 335 mg/cm², excluding variables controlling soc decomposition. Above this threshold, decomposition factors begin to control soc inventory, which we attribute to energetic control on microbial decomposition rates, and relatively weak stabilization of soc in association with fine particles. When combined, these relationships provide an overall prediction of SOC inventory that accounts for 89–90% of the variance observed in the measured data set. Deviations from this relationship are most likely due to additional factors that also control decomposition rate such as hydrochemical and soil drainage conditions not accounted for by soil texture. Outliers within this data set are explained with respect to these conditions. [ABSTRACT FROM AUTHOR]
- Published
- 2006
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13. Patterns in routinely collected, high frequency water quality data in rivers supplying drinking water treatment works.
- Author
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Ashe, Josie, Grand-Clement, Emilie, Luscombe, David J., Graham, Hugh, Savic, Dragan A., and Brazier, Richard E.
- Subjects
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WATER quality , *WATER purification , *WELLHEAD protection , *WATERWORKS , *WATER supply , *DRINKING water - Abstract
The increased use of high temporal resolution in-stream sensors, deployed operationally in industry or for research, produces a large volume of high frequency data. Records generated may contain information value additional to the original purpose, which is not generally explored; and so the full value of these large datasets is rarely realised. Records are available at a frequency and volume that increases the visibility of previously hidden patterns. Alongside targeted research, these data may provide additional insight into hydrochemical behaviour in rivers, and therefore support an improved understanding of both landscape and in-stream processes which can affect drinking water resources.This study investigates the relationships between high frequency water quality parameters and rainfall-runoff driven water quality events in rivers within predominantly rural catchments in the UK. The research improves understanding of the pattern-processes information content of routine data collected from high frequency in-situ sensors in the context of the potential impact on drinking water treatment. The catchments investigated were selected as part of a wider programme of interventions and monitoring for drinking water protection, including farm advise and landscape restoration. Archives for in-situ sensors operated as part of drinking water source monitoring and treatment over the period of the study (2012 - ongoing) contain records for water quality indicators (including; ammonia, colour, conductivity, dissolved oxygen, pH, turbidity) at 5 minute frequency. Additional data (flow, stage, rainfall) from the environmental regulator and from targeted research-based monitoring by the authors were also obtained. The time series datasets were quality controlled using a series of filters written and adapted in R. This was followed by the identification and extraction of rainfall-runoff driven water quality events, which was automated using a base flow separation recursive digital filter and threshold based rainfall-runoff pairing script. A range of visualisation and multivariate techniques were used to identify and investigate patterns, with a focus on hysteresis and both long term and abrupt changes in recorded colour and turbidity. [ABSTRACT FROM AUTHOR]
- Published
- 2019
14. Water quality at catchment scale: how a tiered monitoring approach can highlight multiple benefits.
- Author
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Grand-Clement, Emilie, Ashe, Josie, Carless, Donna, Henderson, Paul, and Brazier, Richard E.
- Subjects
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WATER quality , *WATER quality management , *WATER utilities , *WATER quality monitoring , *POINT sources (Pollution) , *DRINKING water , *WATERSHEDS - Abstract
Catchment management has increasingly become the chosen approach to reduce both point source and diffuse pollution from agriculture in freshwater. In the UK, water companies are, to some extent, driving this movement: investments in pollution reduction upstream are thought to provide a sustainable alternative to increased capital spending for water treatment downstream. However, evidence of both water quality improvement at catchment scale and of the potential financial benefits to water companies and their customers from diffuse pollution reduction are lacking. This knowledge gap is being addressed using the catchment management programme set up by South West Water, the water utility company in southwest England, as a case study. Our work focuses on 9 catchments where the treatment and production of drinking water is being affected by water quality issues from a combination of parameters (i.e. dissolved organic carbon and colour, nutrients, sediments, pesticides, algae, geosmin and 2-MIB) and which are subject to a range of on-farm intervention measures. Overall, the monitoring programme aims to both quantify the extent of the catchment management measures (i.e. farm intervention mapping) and water quality change in associated watercourses. For each catchment, a bespoke, tiered, monitoring programme was set up to quantify water quality change at several spatial and temporal scales. Data collection included: (1) local, intervention-based, monitoring of water quality (i.e. before/after or upstream/downstream), (2) sub-catchment, in-situ and event-based, monitoring of reservoir feeder streams and upstream of abstraction in rivers, and (3) continuous monitoring using data that are routinely collected by the water utility company at catchment scale. Our work shows that, as a first step, mapping of the type, cost, geographical location and extent of catchment interventions is required in order to link interventions and water quality change. However, it only provided a partial understanding of the impact of catchment management on water quality. We show that data at multiple scales (water treatment works and contributing catchments) are needed to evidence the effect of catchment management measures on water quality and inform water utility decision making. Therefore, an appropriate, tiered, monitoring strategy to capture change at these scales is needed. We propose that such strategy is tailored for each catchment and parameters of interest, using techniques that are appropriate depending on the change to be detected, and the type of data required.Process-based modelling techniques of water movements through the catchment may help evaluate a catchment scale understanding of change. However, with sporadic or low-temporal and spatial resolution data, some catchment processes are poorly represented. In addition, change may take longer than expected. Therefore, results remain indicative in the short-term, and are potentially unrepresentative of long-term effects. Overall, the tiered monitoring approach built around operational and regulatory monitoring by the water company and in-situ sampling provided a breadth of data at different spatial and temporal scales. Such a monitoring approach that combines different types and sources of datasets and monitoring strategies at different scales was found to be the most cost-effective way to provide a holistic understanding of change without duplicating efforts. [ABSTRACT FROM AUTHOR]
- Published
- 2019
15. Managing peatland vegetation for drinking water treatment.
- Author
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Ritson, Jonathan P., Bell, Michael, Brazier, Richard E., Grand-Clement, Emilie, Graham, Nigel J. D., Freeman, Chris, Smith, David, Templeton, Michael R., and Clark, Joanna M.
- Abstract
Peatland ecosystem services include drinking water provision, flood mitigation, habitat provision and carbon sequestration. Dissolved organic carbon (DOC) removal is a key treatment process for the supply of potable water downstream from peat-dominated catchments. A transition from peat-forming Sphagnum moss to vascular plants has been observed in peatlands degraded by (a) land management, (b) atmospheric deposition and (c) climate change. Here within we show that the presence of vascular plants with higher annual above-ground biomass production leads to a seasonal addition of labile plant material into the peatland ecosystem as litter recalcitrance is lower. The net effect will be a smaller litter carbon pool due to higher rates of decomposition, and a greater seasonal pattern of DOC flux. Conventional water treatment involving coagulation-flocculation-sedimentation may be impeded by vascular plant-derived DOC. It has been shown that vascular plant-derived DOC is more difficult to remove via these methods than DOC derived from Sphagnum, whilst also being less susceptible to microbial mineralisation before reaching the treatment works. These results provide evidence that practices aimed at re-establishing Sphagnum moss on degraded peatlands could reduce costs and improve efficacy at water treatment works, offering an alternative to 'end-of-pipe' solutions through management of ecosystem service provision. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
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