147 research outputs found
CHANGES IN BACK SQUAT BAR VELOCITY AND PERCEIVED MUSCLE SORENESS FOLLOWING A STANDARDISED RUGBY LEAGUE MATCH SIMULATION
This study examined changes in back squat bar velocity and perceived muscle soreness following a rugby league match simulation protocol. Twenty male rugby league players (age: 19.8 ± 0.7 yrs) were recruited for this study. Back squat bar velocity and perceived muscle soreness of the lower body were collected on four days surrounding a match simulation: -24 h (prior to match simulation), +0 h (after the match simulation), +24 h and +48 h. Compared to baseline (-24h), there were non-significant decreases in maximum (dz=-0.50, moderate) back squat bar velocity +0 h. There was a significant increase in perceived muscle soreness at +0h only (p=0.003). Results suggest that elevated muscle soreness may not indicate impaired neuromuscular performance and highlight the importance of monitoring fatigue via multiple measures to ensure appropriate coaching decisions are made
Investigation into feasibility of hybrid laser-GMAW process for welding high strength quenched and tempered steel
In this study, the feasibility of hybrid laser-gas metal arc welding process for replacement of conventional flux-cored arc welding procedure for welding high strength quenched and tempered steel was investigated. Experimental work focused on optimisation of process parameters to produce joint with desired properties. Hardness of the weld heat affected zone produced by both processes has been measured. Productivity and cost effectiveness of both processes were compared. It was concluded that hybrid laser-gas metal arc welding process is suitable for welding high strength quenched and tempered steel
Making data a first class scientific output : data citation and publication by NERC's Environmental Data Centres
The NERC Science Information Strategy Data Citation and Publication project aims to develop and formalise a method for formally citing and publishing the datasets stored in its environmental data centres. It is believed that this will act as an incentive for scientists, who often invest a great deal of effort in creating datasets, to submit their data to a suitable data repository where it can properly be archived and curated. Data citation and publication will also provide a mechanism for data producers to receive credit for their work, thereby encouraging them to share their data more freely
Early initiation of antiretroviral therapy and associated reduction in mortality, morbidity and defaulting in a nurse-managed, community cohort in Lesotho.
INTRODUCTION: The latest WHO guidelines recommend initiating antiretroviral therapy (ART) at CD4 cell counts less than 350 cells/μl. However, donors and national governments are reluctant to support implementation owing to uncertainty regarding feasibility and relative benefit. Lesotho has supported earlier initiation since 2008. We assessed outcomes comparing early (CD4 cell counts >200 cells/μl) and late (CD4 cell counts ≤200 cells/μl) initiation. METHODS: We describe survival probability among patients initiating ART at CD4 cell counts 200 or less and more than 200 cells/μl and assess associations between baseline CD4 cell counts and mortality, morbidity, loss to follow-up and hospitalization using Cox regression adjusting for confounders identified a priori. RESULTS: Our analysis included 1177 patients; median age was 38 years and the majority (67%) were women. Median time on ART for the overall cohort was 506 days (interquartile range 396-608). Five hundred and thirty eight patients initiated ART at a CD4 cell count 200 cells/μl or less (interquartile range 54-160) and 639 patients initiated at CD4 cell count more than 200 cells/μl (interquartile range 238-321). In multivariate analysis, we found that patients initiating at CD4 cell count more than 200 cells/μl were 68% less likely to die (adjusted hazard ratio 0.32, 95% confidence interval 0.20-0.50), and 39% less likely to be lost to follow-up (adjusted hazard ratio 0.61, 95% confidence interval 0.43-0.87). Initiating ART at CD4 cell count more than 200 cells/μl was also associated with a 27% reduction in the rate of incident morbidity (adjusted hazard ratio 0.73, 95% confidence interval 0.65-0.82) and a 63% decreased rate of hospitalization (adjusted hazard ratio 0.37, 95% confidence interval 0.19-0.73). CONCLUSION: Earlier initiation is feasible in a low resource, high HIV prevalence setting, and provides important benefits in terms of reduced mortality, morbidity, retention and hospitalization. Donors should fully support the implementation of the latest WHO recommendations
Final report on project SP1210: Lowland peatland systems in England and Wales – evaluating greenhouse gas fluxes and carbon balances
Lowland peatlands represent one of the most carbon-rich ecosystems in the UK. As a result of widespread habitat modification and drainage to support agriculture and peat extraction, they have been converted from natural carbon sinks into major carbon sources, and are now amongst the largest sources of greenhouse gas (GHG) emissions from the UK land-use sector. Despite this, they have previously received relatively little policy attention, and measures to reduce GHG emissions either through re-wetting and restoration or improved management of agricultural land remain at a relatively early stage. In part, this has stemmed from a lack of reliable measurements on the carbon and GHG balance of UK lowland peatlands. This project aimed to address this evidence gap via an unprecedented programme of consistent, multi year field measurements at a total of 15 lowland peatland sites in England and Wales, ranging from conservation managed ‘near-natural’ ecosystems to intensively managed agricultural and extraction sites. The use of standardised measurement and data analysis protocols allowed the magnitude of GHG emissions and removals by peatlands to be quantified across this heterogeneous data set, and for controlling factors to be identified. The network of seven flux towers established during the project is believed to be unique on peatlands globally, and has provided new insights into the processes the control GHG fluxes in lowland peatlands. The work undertaken is intended to support the future development and implementation of agricultural management and restoration measures aimed at reducing the contribution of these important ecosystems to UK GHG emissions
Treatment Outcomes and Cost-Effectiveness of Shifting Management of Stable ART Patients to Nurses in South Africa: An Observational Cohort
Lawrence Long and colleagues report that “down-referring” stable HIV patients from a doctor-managed, hospital-based ART clinic to a nurse-managed primary health facility provides good health outcomes and cost-effective treatment for patients
Estimation and validation of InSAR-derived surface displacements at temperate raised peatlands
Peatland surface motion derived from satellite-based Interferometry of Synthetic Aperture Radar (InSAR) is potentially a proxy for groundwater level variations and greenhouse gas emissions from peat soils. Ground validation of these motions at equivalent temporal resolution has proven problematic, either because of limitations of traditional surveying methods or because of limitations with past InSAR time-series approaches. Novel camera-based instrumentation has enabled in-situ measurement of peat surface from mid-2019 to mid-2022 at two large temperate raised bogs undergoing restoration – Cors Fochno and Cors Caron, in mid-Wales, United Kingdom. The cameras provided continuous measurements at sub-millimetre precision and sub-daily temporal resolution. From these data and Sentinel-1 acquisitions spanning mid-2015 to early-2023, we demonstrate that accurate peat surface motion can be derived by InSAR when a combination of interferometric networks with long and short temporal baselines is used. The InSAR time series data closely match the in-situ data at both bogs, and in particular recover well the annual peat surface oscillations of 10-40 mm. Pearson's values for the point-wise correlation of in-situ and InSAR displacements are 0.8–0.9, while 76% of differences are < ±5 mm and 93% are < ±10 mm. RMSE values between multi-annual in-situ and InSAR peat surface displacement rates are ~7 mm·yr−1 and decrease to ∼3.5 mm for individual peat surface motion measurements. Larger differences mainly occur during drought periods. Multi-annual displacement velocities rates based on InSAR indicate long-term subsidence at Cors Caron (maximum −7 mm·yr−1), while Cors Fochno exhibits subsidence at the centre and uplift at the margins (−9 mm·yr−1 to +5 mm·yr−1). Because of the annual peat surface oscillations, however, more robust ground validation of the long-term peat surface motion rates derived from InSAR requires longer time-series of in-situ measurements than are presently available. Nonetheless, the InSAR-derived surface motion rates correlate well spatially with both peat dome elevation and peat thickness. In addition, the annual oscillations in surface motion are synchronous with or lag slightly behind groundwater level changes. A coarse ratio of 10:1 is observed between annual changes in groundwater level and peat surface displacement. Satellite-based InSAR derived from a fusion of short- and long-term temporal baseline networks can thus enable accurate monitoring of hydrologically driven surface motions of moderately degraded to intact temperate raised peatlands
Eddy covariance flux measurements of net ecosystem carbon dioxide exchange from a lowland peatland flux tower network in England and Wales
Peatlands store disproportionately large amounts of soil carbon relative to other terrestrial ecosystems. Over recent
decades, the large amount of carbon stored as peat has proved vulnerable to a range of land use pressures as well
as the increasing impacts of climate change. In temperate Europe and elsewhere, large tracts of lowland peatland
have been drained and converted to agricultural land use. Such changes have resulted in widespread losses of
lowland peatland habitat, land subsidence across extensive areas and the transfer of historically accumulated soil
carbon to the atmosphere as carbon dioxide (CO2). More recently, there has been growth in activities aiming
to reduce these impacts through improved land management and peatland restoration. Despite a long history of
productive land use and management, the magnitude and controls on greenhouse gas emissions from lowland
peatland environments remain poorly quantified.
Here, results of surface-atmosphere measurements of net ecosystem CO2 exchange (NEE) from a network
of seven eddy covariance (EC) flux towers located at a range of lowland peatland ecosystems across the United
Kingdom (UK) are presented. This spatially-dense peatland flux tower network forms part of a wider observation
programme aiming to quantify carbon, water and greenhouse gas balances for lowland peatlands across the
UK. EC measurements totalling over seventeen site years were obtained at sites exhibiting large differences in
vegetation cover, hydrological functioning and land management.
The sites in the network show remarkable spatial and temporal variability in NEE. Across sites, annual
NEE ranged from a net sink of -194 ±38 g CO 2-C m-2 yr-1 to a net source of 784 ±70 g CO2-C m-2 yr-1. The
results suggest that semi-natural sites remain net sinks for atmospheric CO2. Sites that are drained for intensive
agricultural production range from a small net sink to the largest observed source for atmospheric CO2 within the
flux tower network. Extensively managed grassland and a site that was restored from intensive arable land use
represent modest CO2 sources. Temporal variations in CO2 fluxes at sites with permanent vegetation cover are
coupled to seasonal and interannual variations in weather conditions and phenology. The type of crop produced
and agricultural management drive large temporal differences in the CO2 fluxes of croplands on drained lowland peat soils. The main environmental controls on the spatial and temporal variations in CO2 exchange processes will be discussed
Tropical peat surface oscillations are a function of peat condition at North Selangor peat swamp forest, Malaysia
Tropical peatland condition across southeast Asia is deteriorating as a result of conversion to agriculture and urban zones. Conversion begins by lowering the water table, which leads to peat decomposition, subsidence and increased risk of large-scale forest fires. Associated changes in mechanical peat properties impact the magnitude and timing of changes in peatland surface motion, making them a potential proxy for peatland condition. However, such a relationship is yet to be observed in a tropical peatland setting. This study aimed to establish whether patterns of tropical peatland surface motion were a function of peat condition at North Selangor Peat Swamp Forest in Selangor, Malaysia. Results showed that subsidence was greatest at fire-affected scrubland sites, whilst the lowest mean water table levels were found at smallholder oil palm sites. Peat condition and magnitude of tropical peat surface oscillation were significantly different between peat condition classes, whilst peat condition differed with depth. More degraded tropical peats with high bulk density throughout the peat profile due to high surface loading and low mean water table levels showed greater surface oscillation magnitudes. The dominant peat surface oscillation mechanisms present at all sites were compression and shrinkage from changes in water table level. Mean water table level and subsidence rate were related to surface oscillation magnitude. However further work towards measuring surface and within-water table range bulk densities and surface loading is required to better understand the controls on surface oscillation magnitudes
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