The discrimination of geoforensic trace material from close proximity locations by organic profiling using HPLC and plant wax marker analysis by GC

There is a need to develop a wider empirical research base to expand the scope for utilising the organic fraction of soil in forensic geoscience, and to demonstrate the capability of the analytical techniques used in forensic geoscience to discriminate samples at close proximity locations. The determination of wax markers from soil samples by GC analysis has been used extensively in court and is known to be effective in discriminating samples from different land use types. A new HPLC method for the analysis of the organic fraction of forensic sediment samples has also been shown recently to add value in conjunction with existing inorganic techniques for the discrimination of samples derived from close proximity locations. This study compares the ability of these two organic techniques to discriminate samples derived from close proximity locations and finds the GC technique to provide good discrimination at this scale, providing quantification of known compounds, whilst the HPLC technique offered a shorter and simpler sample preparation method and provided very good discrimination between groups of samples of different provenance in most cases. The use of both data sets together gave further improved accuracy rates in some cases, suggesting that a combined organic approach can provide added benefits in certain case scenarios and crime reconstruction contexts

Up and away: ontogenic transference as a pathway for aerial dispersal of microplastics

Microplastics (MPs) are ubiquitous pollutants found in marine, freshwater and terrestrial ecosystems. With so many MPs in aquatic systems it is inevitable that they will be ingested by aquatic organisms, and be transferred up through the food chain. However, to date, no study has considered whether MPs can be transmitted by means of ontogenic transference i.e. between life stages that utilise different habitats. Here, we determine whether fluorescent polystyrene beads could transfer between Culex mosquito life stages and, particularly, could move into the flying adult stage. We show for the first time that MPs can be transferred ontogenically from a feeding (larva) into a non-feeding (pupa) life stage and subsequently into the adult terrestrial life stage. However, transference is dependent on particle size, with smaller 2 µm MPs transferring readily into pupae and adult stages, whilst 15 µm MPs transferred at a significantly reduced rate. Microplastics appear to accumulate in the Malpighian tubule renal excretion system. The transfer of MPs to the adults represents a potential aerial pathway to contamination of new environments. Thus, any organism that feeds on terrestrial life phases of freshwater insects could be impacted by MPs found in aquatic ecosystems

The effect of the introduction of a standard monitoring protocol on the investigations performed on the metabolic control of type 2 diabetes at Addington Hospital Medical Outpatients Department, Durban, South Africa

Background: A comprehensive approach to the control of type 2 diabetes is required to reduce mortality and morbidity. To improve diabetes management, in 2005 a protocol for the monitoring and management of type 2 diabetes, aligned to the 2003 Society for Endocrinology, Metabolism and Diabetes of South Africa (SEMDSA) guidelines, was introduced atAddington Hospital Medical Outpatients Department, Durban, South Africa.Method: Data were collected from 120 randomly selected patients with type 2 diabetes. The number of glycated haemoglobin (HbA1c) and lipid estimations, blood pressure (BP) measurements and body mass indices (BMIs) recorded in 2005 was compared with those recorded in 2008 and 2009. The mean levels of these parameters and the number of patients reaching goal in 2008 were compared with the figures for 2009.Results: In 2005, 18.8% of patients had HbA1c levels measured compared with 82.9% in 2009 (P < 0.01). The mean HbA1c was 6.9% (± 1.9) in 2008 and 6.4% (± 2.0) in 2009 (P = 0.1). BP and BMI was measured in over 93% of patients in 2005, 2008 and 2009. BP goals were attained by 21% of patients in 2008 and 30% in 2009 (P = 0.65). The mean BMI in 2008was 29.4 kg/m2 (24% achieved goal), and in 2009 it was 28.6kg/m2 (29% achieved goal; P = 0.267). Lipid estimations rose significantly from 26% in 2005 to 73% in 2009 (P < 0.01). There was no improvement in the number of patients reaching target lipid levels between 2008 and 2009.Conclusion: The monitoring protocol improved adherence to the SEMDSA 2003 guidelines from 2005 to 2009. Overall glycaemic control was within target, but attainment of most nonglycaemic goals was suboptimal and did not improve over the study period

Space Power Program, Instrumentation and Control System Architecture, Pre-conceptual Design, for Information

The purpose of this letter is to forward the Prometheus preconceptual Instrumentation and Control (I&C) system architecture (Enclosure (1)) to NR for information as part of the Prometheus closeout work. The preconceptual 1&C system architecture was considered a key planning document for development of the I&C system for Project Prometheus. This architecture was intended to set the technical approach for the entire I&C system. It defines interfaces to other spacecraft systems, defines hardware blocks for future development, and provides a basis for accurate cost and schedule estimates. Since the system requirements are not known at this time, it was anticipated that the architecture would evolve as the design of the reactor module was matured

Tobacco and alcohol use among healthcare workers in three public hospitals in KwaZulu-Natal, South Africa

Background: Tobacco use is a risk factor for most of the leading causes of death in the world. Healthcare workers (HCWs) can play an important role in assisting patients to stop smoking, but this role is undermined if they themselves smoke. The study determined the prevalence of tobacco smoking and alcohol use among HCWs in public hospitals in KwaZulu-Natal, South Africa.Methods: In a cross-sectional study, 650 self-administered anonymous questionnaires (primary and secondary questionnaires) were administered to participants between December 2009 and June 2010. Six hundred and twenty primary questionnaires (on smoking) and 630 secondary questionnaires (on alcohol use) were returned, giving a response rate of 95% and 97% respectively. The Pearson chi-square test was used to test for statistical significance.Results: Eleven per cent of the participants were current smokers and 7.1% former smokers, while 27% of neversmokers were constantly exposed to second-hand smoke. Males were 13 times more likely to smoke than their female counterparts (P < 0.001). Never-smokers more frequently counselled their smoking patients to quit compared to former and current smokers (47.5%, 39.5% and 25.8% respectively). Alcohol use problems were reported by 22% of participants (P < 0.001). Current smokers were six times more likely to drink excessively than never-smokers (P < 0.001) and males were ten times more likely than females to drink excessively (P < 0.001).Conclusion: The smoking rate among HCWs is still high, although lower than the national average of 21.4%. A large number of participants reported exposure to second-hand smoke and alcohol use problems. Less than half of the HCWs counselled smoking patients to quit smoking.Keywords: health care worker, tobacco use, alcohol use, patient education for smoking cessatio

Probabilistic Analysis of Optimization Problems on Generalized Random Shortest Path Metrics

Simple heuristics often show a remarkable performance in practice for optimization problems. Worst-case analysis often falls short of explaining this performance. Because of this, "beyond worst-case analysis" of algorithms has recently gained a lot of attention, including probabilistic analysis of algorithms. The instances of many optimization problems are essentially a discrete metric space. Probabilistic analysis for such metric optimization problems has nevertheless mostly been conducted on instances drawn from Euclidean space, which provides a structure that is usually heavily exploited in the analysis. However, most instances from practice are not Euclidean. Little work has been done on metric instances drawn from other, more realistic, distributions. Some initial results have been obtained by Bringmann et al. (Algorithmica, 2013), who have used random shortest path metrics on complete graphs to analyze heuristics. The goal of this paper is to generalize these findings to non-complete graphs, especially Erd\H{o}s-R\'enyi random graphs. A random shortest path metric is constructed by drawing independent random edge weights for each edge in the graph and setting the distance between every pair of vertices to the length of a shortest path between them with respect to the drawn weights. For such instances, we prove that the greedy heuristic for the minimum distance maximum matching problem, the nearest neighbor and insertion heuristics for the traveling salesman problem, and a trivial heuristic for the $k$-median problem all achieve a constant expected approximation ratio. Additionally, we show a polynomial upper bound for the expected number of iterations of the 2-opt heuristic for the traveling salesman problem.Comment: An extended abstract appeared in the proceedings of WALCOM 201

Inorganic Salt Catalysed Hydrothermal Carbonisation (HTC) of Cellulose

The presence of inorganic salts either as part of the substrate or added to the reaction medium are known to significantly affect the reaction pathways during hydrothermal carbonisation (HTC) of biomass. This work aims to understand the influence of salts on hydrothermal carbonisation by processing cellulose in the presence of one or more inorganic salts with different valency. Batch experiments and Differential Scanning Calorimetry were used to investigate the change in reaction pathways during hydrothermal conversion. The effect of salts on the rate of HTC of cellulose can be correlated with the Lewis acidity of the cation and the basicity of the anion. The effect of the anion was more pH-dependent than the cation because it can protonate during the HTC process as organic acids are produced. The introduction of salts with Lewis acidity increases the concentration of low molecular weight compounds in the process water. The addition of a second salt can influence the catalytic effect of the first salt resulting in greater levulinic acid yields at the expense of hydrochar formation. Salts also play an important role in cellulose dissolution and can be used to modify the yield and composition of the hydrochars

Organic Carbon Emissions from the Co-firing of Coal and Wood in a Fixed Bed Combustor

Co-firing of biomass and coal and biomass reduces the emission of pollutants and the overall effects have been extensively studied, but many aspects of the detailed mechanism remain uncertain. A number of studies have been previously made by us of emissions from the combustion in a fixed-bed furnace of bituminous coal and wood, both individually and together, and it was observed that biomass produced less soot and lower NOX emissions. These data are combined with recent measurements of emissions of black carbon (BC) and organic carbon (OC), which are an important source of climate forcing, from the combustion of a number of solid fuels. Conclusion are drawn about the nature of the OC and how the values are dependent on the measurement technique used. Complementary analytical-scale combustion and pyrolysis experiments were also carried out. The results of the analysis of emissions and reaction products, mainly by gas chromatography–mass spectrometry (GC–MS), were interpreted so as to construct a model for pollutant formation during co-firing

Probabilistic Analysis of Facility Location on Random Shortest Path Metrics

The facility location problem is an NP-hard optimization problem. Therefore, approximation algorithms are often used to solve large instances. Such algorithms often perform much better than worst-case analysis suggests. Therefore, probabilistic analysis is a widely used tool to analyze such algorithms. Most research on probabilistic analysis of NP-hard optimization problems involving metric spaces, such as the facility location problem, has been focused on Euclidean instances, and also instances with independent (random) edge lengths, which are non-metric, have been researched. We would like to extend this knowledge to other, more general, metrics. We investigate the facility location problem using random shortest path metrics. We analyze some probabilistic properties for a simple greedy heuristic which gives a solution to the facility location problem: opening the $\kappa$ cheapest facilities (with $\kappa$ only depending on the facility opening costs). If the facility opening costs are such that $\kappa$ is not too large, then we show that this heuristic is asymptotically optimal. On the other hand, for large values of $\kappa$, the analysis becomes more difficult, and we provide a closed-form expression as upper bound for the expected approximation ratio. In the special case where all facility opening costs are equal this closed-form expression reduces to $O(\sqrt[4]{\ln(n)})$ or $O(1)$ or even $1+o(1)$ if the opening costs are sufficiently small.Comment: A preliminary version accepted to CiE 201