ORCID Profile
0000-0003-3486-4109
Current Organisation
University of Oxford
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Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 06-05-2016
Abstract: The Stroke Impact Scale ( SIS ) is a stroke‐specific, quality of life measure recommended for research and clinical practice. Completion rates are suboptimal and could relate to test burden. We derived and validated a short form SIS (SF‐SIS). We examined data from the Virtual International Stroke Trial Archive, generating derivation and validation populations. We derived an SF ‐ SIS by selecting 1 item per domain of SIS , choosing items most highly correlated with total domain score. Our validation described agreement of SF ‐ SIS with original SIS and the SIS ‐16 and correlation with Barthel Index, modified Rankin Scale, National Institutes of Health Stroke Scale, and Euro‐QoL 5 dimensions visual analog scales. We assessed discriminative validity (associations between SF ‐ SIS and factors known to influence outcome [age, physiological parameters, and comorbidity]). We assessed face validity and acceptability by sharing the SF ‐ SIS with a focus group of stroke survivors and multidisciplinary stroke healthcare staff. From 5549 acute study patients (mean age 68.5 [ SD 13] years, mean SIS 64 [ SD 32]) and 332 rehabilitation patients (mean age 65.7 [ SD 11] years, mean SIS 61 [ SD 11]), we derived an 8‐item SF ‐ SIS that demonstrated good agreement with original SIS and good correlation with our chosen functional and quality of life measures (all ρ .70, P .0001). Significant associations were seen with our chosen predictors of stroke outcome in the acute group ( P .0001). The focus group agreed with the choice of items for SF ‐ SIS across 7 of 8 domains . Using multiple, complementary methods, we have derived an SF‐ SIS and demonstrated content, convergent, and discriminant validity. This shortened SIS should allow collection of robust quality of life data with less associated test burden.
Publisher: CSIRO Publishing
Date: 2020
DOI: 10.1071/SR19314
Abstract: No-till (NT) farming has been widely adopted to assist in reducing erosion, lowering fuel costs, conserving soil moisture and improving soil physical, chemical and biological characteristics. Improvements in soil characteristics are often driven by the greater soil organic matter accumulation (as measured by soil organic carbon (SOC)) in NT compared to conventional tillage (CT) farming systems. However, to fully understand the effect of NT it is important to understand temporal changes in SOC by monitoring over an extended period. We investigated the long-term effect of NT and stubble retention (SR) on changes in SOC and total soil nitrogen (STN) using results from an experiment that has been running for 50 years in a semi-arid subtropical region of north-eastern Australia. In this experiment, the effects of tillage (CT vs NT), residue management (stubble burning (SB) vs SR), and nitrogen (N) fertiliser (0 and 90 kg-N ha–1) were measured in a balanced factorial experiment on a Vertisol (Ustic Pellusert). The use of NT, SR and N fertiliser generally improved SOC (by up to 12.8%) and STN stocks (by up to 31.7%) in the 0–0.1 m layer relative to CT, SB and no N fertiliser, with the greatest stocks observed where all three treatments were used in combination. However, declines in SOC (up to 20%) and STN (up to 25%) occurred in all treatments over the course of the experiment, indicating that changes in management practices were unable to prevent a loss of soil organic matter over time in this farming system. However, the NT and SR treatments did lose less SOC than CT and SB treatments, and SR also reduced STN loss. The δ13C analysis of s les collected in 2008 and 2015 highlighted that crop residues have significantly contributed to SOC stocks at the site and that their contribution is increasing over time.
Publisher: Elsevier BV
Date: 10-2021
Publisher: MDPI AG
Date: 02-02-2023
DOI: 10.3390/SU15032679
Abstract: The present investigation evaluated the effect of continuous application ( years) of organic and inorganic fertilisers on soil aggregate stability, aggregate size distribution, aggregate-associated carbon and its fractions, and total macro-nutrient content under the soybean–wheat cropping system in vertisols of the semi-arid region. Seven contrasting treatments consisted of T1 (50% NPK), T2 (100% NPK), T3 (150% NPK), T4 (100% NP), T5 (100% N), T6 (100% NPK + FYM) and T7 Control (crop raised without addition of any nutrient). The highest and lowest percentage of large macroaggregates (11.3%) was found in T6 and T7 treatments. The NPK + FYM (T6) treatments substantially increased the proportion of the macroaggregate fractions ( mm and 2–0.25 mm) than other treatments. However, different manure and fertilisation treatments did not affect the proportion of silt + clay aggregates. Long-term application of 100% NPK + FYM increased mean weight diameter (MWD) and stable water aggregates (WSA) by 35.7 and 6.01% over control. The aggregate-associated SOC followed the trend of large macroaggregates microaggregates small macroaggregates silt + clay fractions. Application of long-term manure plus inorganic fertiliser (T6) has also increased Walkley Black soil organic carbon (WBSC), permanganate oxidisable carbon (KMnO4-C), soil microbial biomass carbon (SMBC), carbon mineralisation (CM), total soil carbon (TSC), total soil N (TSN), total soil phosphorus (TSP) and total soil potassium (STK) by 82.1, 71.6, 182, 42.4, 23.9, 41.6, 117 and 18.4%, respectively, over control (T7). The lowest metabolic quotient (MetQ) value of 5.13 mg CO2–C mg−1 MBC h−1 was obtained in the control treatment (T7). The lowest MetQ was recorded in the integrated application of manure + inorganic fertiliser, i.e., 100% NPK + FYM (T6). Similarly, microbial quotient (MiQ) was also higher in treatment T6 (100% NPK + FYM) and lower in T7 (control). It is concluded that the application of inorganic fertiliser alone is insufficient to maintain soil health and sustainability so, combined application of manure plus inorganic fertilisation is the most important nutrient management practice for long-term soil sustainability because it maintains SOC levels in soils for long periods and ultimately ensures the soil health of soybean–wheat cropping systems in the vertisols of semi-arid regions.
Publisher: Wiley
Date: 03-05-2017
DOI: 10.1002/LDR.2689
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Somasundaram Jayaraman.