4,470 research outputs found

    The macroevolutionary dynamics of mammalian sexual size dimorphism

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    Funding This project was funded by ERC grant no. 788203 (Innovation). Acknowledgements We thank Michael Benton and the Bristol Macroevolution lab group for early project feedback as well as Chris Law and three anonymous reviewers for thoughtful, constructive comments on previous versions of this manuscript.Peer reviewedPublisher PD

    End user voltage regulation to ease urban low-voltage distribution congestion

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    Owing to the increasing demand in the urban areas for new technologies such as heat pumps and electric vehicles (EVs), greater power capacity in low voltage (LV) distribution networks is becoming increasingly important. This study will investigate how to improve the power capacity through the implementation of point of use voltage regulation (PUVR). PUVR relies on a power electronics converter at each end-user. Most LV network cabling has a voltage limit of 1 kV, PUVR exploits this voltage rating to increase the network capacity. This study will describe and discuss the results from a viability study using data from a utility company, which shows that the capacity in the LV network could be increased by an additional 500 kVA. However, it was also found that PUVR using present off-the-shelf converters is not as cost-effective as replacing the LV network cables. Two power electronics topologies have been investigated in the simulation studies to date: the AC chopper circuit and the back-to-back inverter circuit. These two topologies were compared and the AC chopper was found to be a cheaper, more efficient topology. Therefore the AC chopper is more suitable for this application and may increase the viability of the PUVR

    Public perceptions of drinking water: A postal survey of residents with private water supplies

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    Background: In Canada, the legal responsibility for the condition of private water supplies, including private wells and cisterns, rests with their owners. However, there are reports that Canadians test these water supplies intermittently and that treatment of such water is uncommon. An estimated 45% of all waterborne outbreaks in Canada involve non-municipal systems. An understanding of the perceptions and needs of Canadians served by private water supplies is essential, as it would enable public health professionals to better target public education and drinking water policy. The purpose of this study was to investigate the public perceptions of private water supplies in the City of Hamilton, Ontario (Canada), with the intent of informing public education and outreach strategies within the population. Methods: A cross-sectional postal survey of 246 residences with private water supplies was conducted in May 2004. Questions pertained to the perceptions of water quality and alternative water sources, water testing behaviours and the self-identified need for further information. Results: Private wells, cisterns or both, were the source of household water for 71%, 16% and 13% of respondents, respectively. Although respondents rated their water quality highly, 80% also had concerns with its safety. The most common concerns pertained to bacterial and chemical contamination of their water supply and its potential negative effect on health. Approximately 56% and 61% of respondents used in-home treatment devices and bottled water within their homes, respectively, mainly due to perceived improvements in the safety and aesthetic qualities compared to regular tap water. Testing of private water supplies was performed infrequently: 8% of respondents tested at a frequency that meets current provincial guidelines. Two-thirds of respondents wanted more information on various topics related to private water supplies. Flyers and newspapers were the two media reported most likely to be used. Conclusion: Although respondents rated their water quality highly, the majority had concerns regarding the water from their private supply, and the use of bottled water and water treatment devices was extensive. The results of this study suggest important lines of inquiry and provide support and input for public education programs, particularly those related to private water testing, in this population

    Eye See Eye Learn The Benefit of Comprehensive Eye Examinations for Preschoolers

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    Objective: Undetected vision problems in children can lead to permanent vision loss, a condition known as amblyopia. Early detection and treatment of the causes of amblyopia may prevent this vision loss. The objective of this paper is to look for evidence that comprehensive eye examinations upon entry to junior Kindergarten are an effective way to identify and treat vision problems early. methods: Relevant peer-reviewed publications on amblyopia and the importance of comprehensive eye examinations were reviewed. Specific areas investigated include: the prevalence and causes of amblyopia; impact of vision problems on child development and education; impact of amblyopia and/or strabismus on quality of life; and the cost effectiveness of treating amblyopia. The validity of vision screening compared to a comprehensive eye examination was also reviewed. Synthesis:The review suggests that without a complete eye examination many eye or vision problems remain undetected at school entry. Left uncorrected these problems negatively impact child development, education and quality of life. Reduced vision due to amblyopia also restricts future employment opportunities and increases the risk of bilateral visual impairment in adulthood. Examination procedures with high sensitivity and specificity are required to accurately detect these problems. Studies show that amblyopia treatment initiated at an early age is one of the most cost-effective of all health interventions. Conclusion: There is good evidence in the literature that a full eye examination is critical to detect all cases of amblyopia. This and other visual problems can be detected and managed at an early age, which leads to better visual quality of life and economical outcomes. The Eye See Eye Learn program offers the ā€œgold standardā€ of eye care

    Hybrid electric aircraft : state of the art and key electrical system challenges

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    In both Europe and the USA, the aerospace sector is actively pursuing revolutionary design concepts to further improve the environmental impact of air travel. This is partly a result of increasing pressure on the industry from government and other organisations to reduce emissions , despite the continuing increase in air traffic [1] . The aggressive targets set by NASA and the EU [1, 2, 3] (e.g. the Advisory Coun cil for Aviation Research and Innovation in Europe has a target of a 75% reduction in CO2 emissions and a 90% reduction of NOx emissions by 2050) cannot be achieved through marginal improvements in turbine technology or aircraft design. Rather, disruptive technologies and more innovative aircraft must be considered

    Establishing viable fault management strategies for distributed electrical propulsion aircraft

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    Electrical propulsion has the potential to increase aircraft performance. However, this will require the design and development of an appropriate aircraft electrical system to power the propulsor motors. In order to protect this system against electrical faults, which have the potential to threaten the safety of the aircraft, a robust fault management strategy (FMS) is required. The FMS will comprise aspects of system design such as redundancy, reliability and reconfiguration and will rely on a range of protection devices deployed on the electrical system to intercept and manage faults. The electrical architecture will be shaped by the FMS as this will determine the optimal configuration to enable security of supply. The protection system is integral to the system design. Hence it must to be considered from the outset, as part of the wider aircraft concept development. This paper presents a robust framework to develop the optimal FMS for an electrical propulsion aircraft, which is subject to all the relevant aircraft constraints and incorporates the available protection devices for a chosen aircraft for a given developmental timeframe. A case study is then presented in which this protection design methodology is applied to the NASA STARC-ABL aircraft concept in order to demonstrate that the available protection for an electrical propulsion aircraft defines the possible electrical architectures

    What is the mechanism effect that links social support to coping and psychological outcome within individuals affected by prostate cancer? Real time data collection using mobile technology

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    Abstract Unmet support needs are prevalent in men affected by prostate cancer. Moreover, little is known about the optimal type of social support, or its mechanism effect between coping and emotional outcome in men affected by this disease to identify areas for clinical intervention. This study aimed to empirically test the propositions of social support theory in ā€œreal timeā€ within individual men living with and beyond prostate cancer. Purposeful sub-sample from a larger prospective longitudinal study of prostate cancer survivors, took part in real time data collection using mobile technology. Self-reports were collected for 31 days prompted by an audio alarm 3 times per day (a total of 93 data entries) for each of the 12 case studies. Electronic data were analysed using time series analysis. Majority of response rates were >90%. Men reported a lack of satisfaction with their support over time. Testing the propositions of social support theory ā€œwithin individualsā€ over time demonstrated different results for main effect, moderation and mediation pathways that linked coping and social support to emotional outcome. For two men, negative effects of social support were identified. For six men the propositions of social support theory did not hold considering their within-person data. This innovative study is one of the first, to demonstrate the acceptability of e-health technology in an ageing population of men affected by prostate cancer. Collectively, the case series provided mixed support for the propositions of social support theory, and demonstrates that ā€œone size does not fit allā€

    Common aquatic pollutants modify hemocyte immune responses in Biomphalaria glabrata.

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    Funding The studentship supporting this research was awarded by the UK Natural Environment Research Council (NERC). Acknowledgments We are grateful to Dr. David Rollinson (Natural History Museum) for providing B. glabrata snails and to Drs. Nuha Mansour and Quentin Bickle (London School of Hygiene and Tropical Medicine) for providing parasite material. We thank the UK Natural Environment Research Council (NERC) for funding.Peer reviewedPublisher PD
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