Operator related attenuation effects in radiometric surveys

Radiometric surveys using airborne, vehicular mounted or backpack detector systems are increasingly used to identify and evaluate complex distributions of radioactivity in the environment. The signals detected depend on the energy and spatial distribution of radioactive sources, the material properties of the environment and the specific properties of the detector systems employed. Materials in close vicinity to the detector such as housings, and intermediate materials may have a critical impact on detection efficiency, and must therefore be taken into account in calibration. This study evaluates the effect of shielding by the body of the operator in backpack surveys. Controlled experiments using point sources and absorbers, chosen to represent the form and composition of human tissue, were conducted, and coupled to an analytical radiation transport model to estimate attenuation factors for mapping of 137Cs. In this way generic factors to correct for this effect using portable spectrometers have been determined. The results compare well with observations at sampled calibration sites in Fukushima and the Solway area in Scotland. Reductions of the 137Cs full-energy peak intensity between 20% and 30% may be expected depending on operator stature and the offset position of backpack systems. Similar effects may be present for other radiometric systems carried by a human operator

Geographic variation in baseline innate immune function does not follow variation in aridity along a tropical environmental gradient

Geographic variation in aridity determines environmental productivity patterns, including large-scale variability in pathogens, vectors and associated diseases. If disease risk decreases with increasing aridity and is matched by immune defense, we predict a decrease in innate immune function along a gradient of increasing aridity from the cool-wet forest to the hot-dry Sahel, from south to north in Nigeria. We sampled blood and measured five innate immune indices from 286 Common Bulbuls Pycnonotus barbatus between 6 and 13 degrees N. We sampled in the dry season; we resampled the first location (Jos) also as the last sample location to test temporal change in immune function. Immune indices did not decrease with aridity. One immune index, nitric oxide concentration showed a weak quadratic pattern. In Jos, ovotransferrin concentration, haemagglutination and haemolysis titres increased 12 weeks into the dry season, contrary to expectations that immune indices should decrease with increased dryness. In this tropical system, innate immune function does not decrease with increasing aridity but temporal factors within a location may influence immune function more strongly than spatial variation in aridity, suggesting that immune variation does not follow a simple environmental productivity pattern. Consequently, caution should probably be exercised in predicting effects of climate variability on immune function or disease risk

Demonstration of lightweight gamma spectrometry systems in urban environments

Urban areas present highly complex radiation environments; with small scale features resulting from different construction materials, topographic effects and potential anthropogenic inputs from past industrial activity or other sources. Mapping of the radiation fields in urban areas allows a detailed assessment of exposure pathways for the people who live and work there, as well as locating discrete sources of activity that may warrant removal to mitigate dose to the general public. These areas also present access difficulties for radiometric mapping using vehicles or aircraft. A lightweight portable gamma spectrometry system has been used to survey sites in the vicinity of Glasgow to demonstrate the possibilities of radiometric mapping of urban areas, and to investigate the complex radiometric features such areas present. Variations in natural activity due to construction materials have been described, the presence of 137Cs used to identify relatively undisturbed ground, and a previously unknown NORM feature identified. The effect of topographic enclosure on measurements of activity concentration has been quantified. The portable system is compared with the outputs that might be expected from larger vehicular or airborne systems. For large areas airborne surveys are the most cost effective approach, but provide limited spatial resolution, vehicular surveys can provide sparse exploratory data rapidly or detailed mapping of open areas where off-road access is possible. Backpack systems are ideally suited to detailed surveys of small areas, especially where vehicular access is difficult

Incidence of abortion-related near-miss complications in Zambia: cross-sectional study in Central, Copperbelt and Lusaka Provinces

OBJECTIVES: To describe the magnitude and severity of abortion-related complications in health facilities and calculate the incidence of abortion-related near-miss complications at the population level in three provinces in Zambia, a country where abortion is legal but stigmatized. STUDY DESIGN: We conducted a cross-sectional study in 35 district, provincial and tertiary hospitals over 5 months. All women hospitalized for abortion-related complications were eligible for inclusion. Cases of abortion-related near-miss, moderate and low morbidity were identified using adapted World Health Organization (WHO) near-miss and the prospective morbidity methodology criteria. Incidence was calculated by annualizing the number of near-misses and dividing by the population of women of reproductive age. We calculated the abortion-related near-miss rate, abortion-related near-miss ratio and the hospital mortality index. RESULTS: Participating hospitals recorded 26,723 births during the study. Of admissions for post-abortion care, 2406 (42%) were eligible for inclusion. Near-misses constituted 16% of admitted complications and there were 14 abortion-related maternal deaths. The hospital mortality index was 3%; the abortion-related near-miss rate for the three provinces was 72 per 100,000 women, and the near-miss ratio was 450 per 100,000 live births. CONCLUSIONS: Abortion-related near-miss and mortality are challenges for the Zambian health system. Adapted to reflect health systems capabilities, the WHO near-miss criteria can be applied to routine hospital records to obtain useful data in low-income settings. Reducing avoidable maternal mortality and morbidity due to abortion requires efforts to de-stigmatize access to abortion provision, and expanded access to modern contraception. IMPLICATIONS: The abortion-related near-miss rate is high in Zambia compared with other restrictive contexts. Our results suggest that near-miss is a promising indicator of unsafe abortion; can be measured using routine hospital data, conveniently defined using the WHO criteria; and can be incorporated into the frequently utilized prospective morbidity methodology

Breeding limits foraging time : evidence of interrupted foraging response from body mass variation in a tropical environment

Funds were received from the Ubbo Emmius grant, Univ. of Groningen and also from the Univ. of St Andrews.Birds should store body reserves if starvation risk is anticipated; this is known as an ‘interrupted foraging response’. If foraging remains unrestricted, however, body mass should remain low to limit the predation risk that gaining and carrying body reserves entails. In temperate environments mass gain in female birds during breeding is often attributed to egg formation and mass loss after incubation to flight adaptation or the effect of reproductive workload, rather than as a result of an adaptive interrupted foraging response to the limited foraging time or unpredictable foraging conditions that breeding demands. In tropical environments, foraging conditions vary more within the breeding season than in temperate environments, and so studies in tropical environments are more suited to decouple the potentially confounded effects of increase in body reserves versus egg formation on the body mass of breeding birds. In this study, we test whether breeding results in an interrupted foraging response in a tropical savannah system using body mass data collected over a 15-year period from female Common Bulbuls Pycnonotus barbatus. This species breeds both in the wet and dry season, despite fewer resources being available in the dry season. Breeding stage predicted female body mass: body mass peaked abruptly during incubation, but was not closely associated with the egg-laying stage, and declined during brood rearing. Breeding females were heavier in the dry season than in the wet season. In the dry season, heavier birds were more likely to incubate eggs or brood chicks. These observations suggest that increased body reserves are required to buffer the consequence of limited foraging time or impoverished foraging conditions, which may be most pronounced during incubation and in the dry season, respectively. Such mass increases are consistent with an interrupted foraging response, which may apply to temperate zone birds experiencing foraging restrictions during breeding.PostprintPeer reviewe

The effect of flight line spacing on radioactivity inventory and spatial feature characteristics of airborne gamma-ray spectrometry data

Airborne Gamma Spectrometry (AGS) is well suited to the mapping of radioactivity in the environment. Flight parameters (e.g. speed and line spacing) directly affect the rate of area coverage, cost, and data quality of any survey. The influences of line spacing have been investigated for data from inter‐tidal, coastal and upland environments with a range of <sup>137</sup>Cs activity concentrations and depositional histories. Estimates of the integrated <sup>137</sup>Cs activity (‘inventory’) within specified areas and the shapes of depositional features were calculated for subsets of the data at different line spacings. Features with dimensions greater than the line spacing show variations in inventory and area of less than 3%, and features with dimensions less than the line spacing show larger variations and a decreased probability of detection. The choice of line spacing for a task is dependent on the dimensions of the features of interest and required edge definition. Options for line spacing for different tasks are suggested. It is noted that for regional mapping, even 5–10 km line spacing can produce useful data

Nanoindentation Of Si Nanostructures: Buckling And Friction At Nanoscales

A nanoindentation system was employed to characterize mechanical properties of silicon nanolines (SiNLs), which were fabricated by an anisotropic wet etching (AWE) process. The SiNLs had the linewidth ranging from 24 nm to 90 nm, having smooth and vertical sidewalls and the aspect ratio (height/linewidth) from 7 to 18. During indentation, a buckling instability was observed at a critical load, followed by a displacement burst without a load increase, then a full recovery of displacement upon unloading. This phenomenon was explained by two bucking modes. It was also found that the difference in friction at the contact between the indenter and SiNLs directly affected buckling response of these nanolines. The friction coefficient was estimated to be in a range of 0.02 to 0.05. For experiments with large indentation displacements, irrecoverable indentation displacements were observed due to fracture of Si nanolines, with the strain to failure estimated to be from 3.8% to 9.7%. These observations indicated that the buckling behavior of SiNLs depended on the combined effects of load, line geometry, and the friction at contact. This study demonstrated a valuable approach to fabrication of well-defined Si nanoline structures and the application of the nanoindentation method for investigation of their mechanical properties at the nanoscale.Microelectronics Research Cente

Investigating and learning lessons from early experiences of implementing ePrescribing systems into NHS hospitals:a questionnaire study

Background: ePrescribing systems have significant potential to improve the safety and efficiency of healthcare, but they need to be carefully selected and implemented to maximise benefits. Implementations in English hospitals are in the early stages and there is a lack of standards guiding the procurement, functional specifications, and expected benefits. We sought to provide an updated overview of the current picture in relation to implementation of ePrescribing systems, explore existing strategies, and identify early lessons learned.Methods: a descriptive questionnaire-based study, which included closed and free text questions and involved both quantitative and qualitative analysis of the data generated.Results: we obtained responses from 85 of 108 NHS staff (78.7% response rate). At least 6% (n = 10) of the 168 English NHS Trusts have already implemented ePrescribing systems, 2% (n = 4) have no plans of implementing, and 34% (n = 55) are planning to implement with intended rapid implementation timelines driven by high expectations surrounding improved safety and efficiency of care. The majority are unclear as to which system to choose, but integration with existing systems and sophisticated decision support functionality are important decisive factors. Participants highlighted the need for increased guidance in relation to implementation strategy, system choice and standards, as well as the need for top-level management support to adequately resource the project. Although some early benefits were reported by hospitals that had already implemented, the hoped for benefits relating to improved efficiency and cost-savings remain elusive due to a lack of system maturity.Conclusions: whilst few have begun implementation, there is considerable interest in ePrescribing systems with ambitious timelines amongst those hospitals that are planning implementations. In order to ensure maximum chances of realising benefits, there is a need for increased guidance in relation to implementation strategy, system choice and standards, as well as increased financial resources to fund local activitie

Novel deployment of a covered duodenal stent in open surgery to facilitate closure of a malignant duodenal perforation

<p>Abstract</p> <p>Background</p> <p>Its a dilemma to attempt a palliative procedure to debulk the tumour and/or prevent future obstructive complications in a locally advanced intra abdominal malignancy.</p> <p>Case presentation</p> <p>A 38 year old Vietnamese man presented with a carcinoma of the colon which had invaded the gallbladder and duodenum with a sealed perforation of the second part of the duodenum. Following surgical exploration, it was evident that primary closure of the perforated duodenum was not possible due to the presence of unresectable residual tumour.</p> <p>Conclusion</p> <p>We describe a novel technique using a covered duodenal stent deployed at open surgery to aid closure of a malignant duodenal perforation.</p