940 research outputs found
Characterising the ‘in situ’ Thermal Behaviour of Selected Electrical Machine Insulation and Impregnation Materials
Borrelia, Ehrlichia, and Rickettsia spp. in Ticks Removed from Persons, Texas, USA
Some tick-borne agents may pose yet-unknown public health risks
Using Unmanned Aerial Vehicle (UAV) Imagery to Characterise Pursuit-Diving Seabird Association With Tidal Stream Hydrodynamic Habitat Features
Acknowledgments We gratefully acknowledge the support of colleagues at Marine Scotland Science, the crew and scientists of the MRV Scotia 2018 cruise (particularly Chief Scientist Adrian Tait) and ERI interns: Gael Gelis and Martin Forestier. We gratefully acknowledge the constructive comments from reviewers. Finally, we also want to thank Ella Benninghaus for providing the auk illustrations used within the paper. Funding This work was funded by the Bryden Centre project, supported by the European Union’s INTERREG VA Programme, and managed by the Special EU Programmes Body (SEUPB). The views and opinions expressed in this paper do not necessarily reflect those of the European Commission or the Special EU Programmes Body (SEUPB). Aspects of this research were also funded by a Royal Society Research Grant [RSG\R1\180430], the NERC VertIBase project [NE/N01765X/1], the UK Department for Business, Energy, and Industrial Strategy’s offshore energy Strategic Environmental Assessment programme and EPSRC Supergen ORE Hub [EP/S000747/1].Peer reviewedPublisher PD
Using laboratory experience to investigate student learning trends in chemistry
Surveys commonly utilised as part of the Advancing Science by Enhancing Learning in the Laboratory (ASELL) project have been used to investigate the perceptions of first year undergraduate chemistry students during their laboratory sessions at the University of Adelaide. From 2011, data from these surveys has provided insights into many facets of the learning experience. Quality of experiments and laboratory courses in first year undergraduate chemistry has been evaluated from the student perspective, and the effects of any revisions to past experiments and the overall laboratory course structure have been identified. Trends have been observed in the overall perception of experiments, with relation to macro, sub-micro and symbolic representations of concepts. Prominent factors contributing to the overall learning experience have been investigated, and cases in which these factors contribute most and least prominently have been observed. Reasons for relatively poor perception of experiments often appear related to effects generated by difficulty thinking beyond the macro domain of representation. Additionally, visual appeal has been seen to be a strong source of interest in experiments. The degree to which particular facets of the laboratory experience contribute to the perceived overall learning experience appears to be variable
Biogeochemical Cycling of 99Tc in Alkaline Sediments
99Tc will be present in significant quantities in radioactive wastes including intermediate-level waste (ILW). The internationally favored concept for disposing of higher activity radioactive wastes including ILW is via deep geological disposal in an underground engineered facility located ∼200–1000 m deep. Typically, in the deep geological disposal environment, the subsurface will be saturated, cement will be used extensively as an engineering material, and iron will be ubiquitous. This means that understanding Tc biogeochemistry in high pH, cementitious environments is important to underpin safety case development. Here, alkaline sediment microcosms (pH 10) were incubated under anoxic conditions under “no added Fe(III)” and “with added Fe(III)” conditions (added as ferrihydrite) at three Tc concentrations (10–11, 10–6, and 10–4 mol L–1). In the 10–6 mol L–1 Tc experiments with no added Fe(III), ∼35% Tc(VII) removal occurred during bioreduction. Solvent extraction of the residual solution phase indicated that ∼75% of Tc was present as Tc(IV), potentially as colloids. In both biologically active and sterile control experiments with added Fe(III), Fe(II) formed during bioreduction and >90% Tc was removed from the solution, most likely due to abiotic reduction mediated by Fe(II). X-ray absorption spectroscopy (XAS) showed that in bioreduced sediments, Tc was present as hydrous TcO2-like phases, with some evidence for an Fe association. When reduced sediments with added Fe(III) were air oxidized, there was a significant loss of Fe(II) over 1 month (∼50%), yet this was coupled to only modest Tc remobilization (∼25%). Here, XAS analysis suggested that with air oxidation, partial incorporation of Tc(IV) into newly forming Fe oxyhydr(oxide) minerals may be occurring. These data suggest that in Fe-rich, alkaline environments, biologically mediated processes may limit Tc mobility.Peer reviewe
Challenges Facing the Implementation of Pico-Hydropower Technologies
840 million people living in rural areas across the world lack access to electricity, creating a large imbalance in the development potential between urban and rural areas. Pico-hydropower offers a cost-effective way of accessing electricity, where the resource exists. This paper discusses and critically examines several challenges that remain in implementing pico-hydropower systems, such as local manufacturing, maintenance and repair of turbines, low-head solutions, dealing with variation in the water flow between seasons, the ability to deal with income generating loads and low system power and capacity factor. The solutions to many of these problems exist; several low head turbine systems are appearing on the market, and new power electronic packages are able to improve the system capacity factor. Some turbines are now being designed for local construction using design for manufacturing rules, so only basic workshop tools and process are required to build turbine systems and components, and enabling turbines to be locally repaired. Through the commercialisation and implementation of these solutions, the proliferation of pico-hydropower systems can take place providing low cost sustainable electricity for remote communities, but this requires a stronger emphasis in social awareness and policy. Three critical enabling factors for the success of pico-hydropower projects are identified through this analysis: understanding the local context, financial sustainability and stakeholder awareness
Vertical integration and firm boundaries : the evidence
Since Ronald H. Coase's (1937) seminal paper, a rich set of theories has been developed that deal with firm boundaries in vertical or input–output structures. In the last twenty-five years, empirical evidence that can shed light on those theories also has been accumulating. We review the findings of empirical studies that have addressed two main interrelated questions: First, what types of transactions are best brought within the firm and, second, what are the consequences of vertical integration decisions for economic outcomes such as prices, quantities, investment, and profits. Throughout, we highlight areas of potential cross-fertilization and promising areas for future work
The agreement between cervical abnormalities identified by cytology and detection of high-risk types of human papillomavirus
Objectives and design. Human papillomavirus (HPV) is causally associated with cervical cancer. Using the Digene Hybrid Capture 2 high-risk HPV test (HC2), we investigated the prevalence of high-risk HPV in cervical specimens, and compared results with those of Papanicolaou (Pap) smears taken concurrently Subjects and setting. Cervical specimens were obtained from women attending hospitals/community health centres in the Western Cape province of South Africa. They were participating in a case-control study of the association of hormonal contraceptives and invasive cervical cancer.
Results. Of 1 491 women tested, 254 (17%) were HPV DNA positive. The age-specific prevalence of HPV was 36/97 (37.1%) in those aged < 30 years, 78/369 (21.1%) in those aged 30 - 39 years, 78/603 (12.9%) in those aged 40 - 49 years and 62/422 (14.7%) in those aged 50 - 59 years. In women with normal cytology the prevalence of HPV was 10.9% (138/1 264); in those with abnormal squamous cells of unknown significance (AS-CUS) it was 30.8% (36/117); in those with low-grade squamous intraepithelial lesions (LSIL) it was 63.2% (36/57), and in those with high-grade squamous intraepithelial lesions (HSIL) it was 83% (44/53). The odds ratio between HPV and HSIL in women aged 40 - 59 years was 57.1 (confidence interval 22.4 - 170.7).
Conclusions. HC2 detected a high prevalence of HPV (17%) in this population. Most women with HSIL (83%) were positive, indicating that HPV testing of AS-CUS women may aid in management. When costs decrease, HC2 could be introduced as an adjunct to Pap smears in identifying women at risk for high-grade cervical disease and could be useful in the maintenance of cervical health in those who remain Pap smear negative
Inter- and intra-observer reliability of the Baumann angle of the humerus in children with supracondylar humeral fractures
The Baumann angle of the humerus has been commonly used as an outcome measure for supracondylar fractures in children. However, there is limited or no information about the reliability of this measurement. The purpose of this study was to determine the inter-observer reliability (IEOR) and intra-observer reliability (IAOR) of the Baumann angle of the humerus. The Baumann angle of the humerus was measured by five observers on the anteroposterior radiographs of 35 children’s elbows, all of which had sustained a nondisplaced supracondylar humeral fracture. The values of IEOR and IAOR were calculated using a Pearson coefficient of correlation. Ranges of differences in the measurement of the Baumann angle of the humerus were established, and the percentage of agreement between observers was then calculated using those ranges. The Baumann angle of the humerus is a simple, repeatable and reliable measurement that can be used for the determination of the outcome of supracondylar humeral fractures in the paediatric population. An excellent IEOR was found for the measurement of the Baumann angle (r = 0.78, p = 0.0001). When the difference between observers in the reported measurement of the Baumann’s angle was calculated to be within seven degrees of each other, at least four of the five observers agreed 100% of the time. Similarly, excellent values of IAOR were found for the measurement of the Baumann’s angle (r = 0.80, p = 0.0001). Level of evidence for this study was III
- …