1,430 research outputs found
Individualised reflexivity and corporate social responsibility: perspectives on the consumer
Development and Assessment of an Updated Tool for the Design of Soil and Water Conservation Structures in the Sugar Industry of South Africa
Sugarcane in South Africa is grown on wide-ranging soils, sometimes in non-ideal climates and on steep topographies where soils are vulnerable to erosion. Sugarcane fields are protected against erosion through, inter alia, the use of engineered waterways, contour banks and spill-over roads. A comparison of design norms in the National Soil Conservation Manual and norms used in the sugar industry clearly shows discrepancies that need to be investigated. Furthermore, the sugar industry design nomograph was developed based on an unsustainable soil loss limit, does not include any regional variations of climate and the impact on soil erosion and runoff and does not include vulnerability during break cropping. The aim of this research was to develop and assess updated design norms for soil and water conservation structures in the sugar industry of South Africa. The Agricultural Catchments Research Unit (ACRU) model estimates event-based erosion and the ACRU was used to conduct simulations for the different practices in the sugar industry and the outcome used to build the updated tool for the design of soil and water conservation structures in the sugar industry of South Africa, using MS Access with a graphical user interface. The updated tool is robust, based on sustainable soil loss limits, includes regional variations of climate and their impact on soil erosion and runoff and also includes vulnerability during break cropping. It is more representative of conditions in the sugar industry of South Africa and therefore recommended for use in place of the current sugar industry design norms
Constraining Dark Matter in the MSSM at the LHC
In the event that R-Parity conserving supersymmetry (SUSY) is discovered at
the LHC, a key issue which will need to be addressed will be the consistency of
that signal with astrophysical and non-accelerator constraints on SUSY Dark
Matter. This issue is studied for the SPA benchmark model based on measurements
of end-points and thresholds in the invariant mass spectra of various
combinations of leptons and jets. These measurements are used to constrain the
soft SUSY breaking parameters at the electroweak scale in a general MSSM model.
Based on these constraints, we assess the accuracy with which the Dark Matter
relic density can be measured.Comment: 21 pages, 12 figure
Epidemiology of Subpatent Plasmodium Falciparum Infection: Implications for Detection of Hotspots with Imperfect Diagnostics.
At the local level, malaria transmission clusters in hotspots, which may be a group of households that experience higher than average exposure to infectious mosquitoes. Active case detection often relying on rapid diagnostic tests for mass screen and treat campaigns has been proposed as a method to detect and treat individuals in hotspots. Data from a cross-sectional survey conducted in north-western Tanzania were used to examine the spatial distribution of Plasmodium falciparum and the relationship between household exposure and parasite density. Dried blood spots were collected from consenting individuals from four villages during a survey conducted in 2010. These were analysed by PCR for the presence of P. falciparum, with the parasite density of positive samples being estimated by quantitative PCR. Household exposure was estimated using the distance-weighted PCR prevalence of infection. Parasite density simulations were used to estimate the proportion of infections that would be treated using a screen and treat approach with rapid diagnostic tests (RDT) compared to targeted mass drug administration (tMDA) and Mass Drug Administration (MDA). Polymerase chain reaction PCR analysis revealed that of the 3,057 blood samples analysed, 1,078 were positive. Mean distance-weighted PCR prevalence per household was 34.5%. Parasite density was negatively associated with transmission intensity with the odds of an infection being subpatent increasing with household exposure (OR 1.09 per 1% increase in exposure). Parasite density was also related to age, being highest in children five to ten years old and lowest in those >β40 years. Simulations of different tMDA strategies showed that treating all individuals in households where RDT prevalence was above 20% increased the number of infections that would have been treated from 43 to 55%. However, even with this strategy, 45% of infections remained untreated. The negative relationship between household exposure and parasite density suggests that DNA-based detection of parasites is needed to provide adequate sensitivity in hotspots. Targeting MDA only to households with RDT-positive individuals may allow a larger fraction of infections to be treated. These results suggest that community-wide MDA, instead of screen and treat strategies, may be needed to successfully treat the asymptomatic, subpatent parasite reservoir and reduce transmission in similar settings
Scallop swimming kinematics and muscle performance: modelling the effects of "within-animal" variation in temperature sensitivity
Escape behaviour was investigated in Queen scallops (Aequipecten opercularis) acclimated to 5, 10 or 15 degrees C and tested at their acclimation temperature. Scallops are active molluscs, able to escape from predators by jet-propelled swimming using a striated muscle working in opposition to an elastic hinge ligament. The first cycle of the escape response was recorded using high-speed video ( 250 Hz) and whole-animal velocity and acceleration determined. Muscle shortening velocity, force and power output were calculated using measurements of valve movement and jet area, and a simple biomechanical model. The average shortening speed of the adductor muscle had a Q(10) of 2.04, significantly reducing the duration of the jetting phase of the cycle with increased temperature. Muscle lengthening velocity and the overall duration of the clap cycle were changed little over the range 5 - 15 degrees C, as these parameters were controlled by the relatively temperature-insensitive, hinge ligament. Improvements in the average power output of the adductor muscle over the first clap cycle ( 222 vs. 139 W kg(-1) wet mass at 15 and 5 degrees C respectively) were not translated into proportional increases in overall swimming velocity, which was only 32% higher at 15 degrees C ( 0.37m s(-1)) than 5 degrees C (0.28 m s(-1))
Latent cluster analysis of ALS phenotypes identifies prognostically differing groups
BACKGROUND
Amyotrophic lateral sclerosis (ALS) is a degenerative disease predominantly affecting motor neurons and manifesting as several different phenotypes. Whether these phenotypes correspond to different underlying disease processes is unknown. We used latent cluster analysis to identify groupings of clinical variables in an objective and unbiased way to improve phenotyping for clinical and research purposes.
METHODS
Latent class cluster analysis was applied to a large database consisting of 1467 records of people with ALS, using discrete variables which can be readily determined at the first clinic appointment. The model was tested for clinical relevance by survival analysis of the phenotypic groupings using the Kaplan-Meier method.
RESULTS
The best model generated five distinct phenotypic classes that strongly predicted survival (p<0.0001). Eight variables were used for the latent class analysis, but a good estimate of the classification could be obtained using just two variables: site of first symptoms (bulbar or limb) and time from symptom onset to diagnosis (p<0.00001).
CONCLUSION
The five phenotypic classes identified using latent cluster analysis can predict prognosis. They could be used to stratify patients recruited into clinical trials and generating more homogeneous disease groups for genetic, proteomic and risk factor research
Choice of activity-intensity classification thresholds impacts upon accelerometer-assessed physical activity-health relationships in children
It is unknown whether using different published thresholds (PTs) for classifying physical activity (PA) impacts upon activity-health relationships. This study explored whether relationships between PA (sedentary [SED], light PA [LPA], moderate PA [MPA], moderate-to-vigorous PA, vigorous PA [VPA]) and health markers differed in children when classified using three different PTs
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