1,017 research outputs found

    Impact hazard protection efficiency by a small kinetic impactor

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    In this paper the ability of a small kinetic impactor spacecraft to mitigate an Earth-threatening asteroid is assessed by means of a novel measure of efficiency. This measure estimates the probability of a space system to deflect a single randomly-generated Earth-impacting object to a safe distance from the Earth. This represents a measure of efficiency that is not biased by the orbital parameters of a test-case object. A vast number of virtual Earth-impacting scenarios are investigated by homogenously distributing in orbital space a grid of 17,518 Earth impacting trajectories. The relative frequency of each trajectory is estimated by means Opik’s theory and Bottke’s near Earth objects model. A design of the entire mitigation mission is performed and the largest deflected asteroid computed for each impacting trajectory. The minimum detectable asteroid can also be estimated by an asteroid survey model. The results show that current technology would likely suffice against discovered airburst and local damage threats, whereas larger space systems would be necessary to reliably tackle impact hazard from larger threats. For example, it is shown that only 1,000 kg kinetic impactor would suffice to mitigate the impact threat of 27.1% of objects posing similar threat than that posed by Apophis

    Exploring barriers to and enablers of adequate healthcare for Indigenous Australian prisoners with cancer: a scoping review drawing on evidence from Australia, Canada and the United States

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    Published: 3 May 2016Background: International frameworks supported by national principles in Australia stipulate that prisoners should be provided with health services equivalent to those provided in the general community. However, a number of barriers unique to the prison system may hinder the provision of equitable healthcare for this population. In Australia, Indigenous people carry a greater burden of cancer mortality, which the Cancer Data and Aboriginal Disparities (CanDAD) project is seeking to address. During the course of recruiting participants to the CanDAD study, Indigenous Australian prisoners with cancer emerged as an important, under-researched but difficult to access sub-group. Methods: This scoping review sought to identify barriers and facilitators of access to adequate and equitable healthcare for Indigenous Australian prisoners with cancer in Australia. This review demonstrated a lack of research and, as such, the scoping review was extended to prisoners with cancer in Australia, New Zealand, the United States and Canada. This approach was taken in order to summarise the existing body of evidence regarding the barriers and facilitators of access to adequate and equitable healthcare for those who are incarcerated and suffering from cancer, and highlight areas that may require further investigation. Results: Eight studies or commentaries were found to meet the inclusion criteria. This limited set of findings pointed to a range of possible barriers faced by prisoners with cancer, including a tension between the prisons’ concern with security versus the need for timely access to medical care. Conclusion: Findings identified here offer potential starting points for research and policy development. Further research is needed to better elucidate how barriers to adequate cancer care for prisoners may be identified and overcome, in Australia and internationally. Furthermore, given Indigenous Australians’ over-burden of cancer mortality and over-representation in the prison system, further research is needed to identify whether there are a unique set of barriers for this group.Jessica Olds, Rachel Reilly, Paul Yerrell, Janet Stajic, Jasmine Micklem, Kim Morey and Alex Brow

    Advanced perception, navigation and planning for autonomous in-water ship hull inspection

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    Inspection of ship hulls and marine structures using autonomous underwater vehicles has emerged as a unique and challenging application of robotics. The problem poses rich questions in physical design and operation, perception and navigation, and planning, driven by difficulties arising from the acoustic environment, poor water quality and the highly complex structures to be inspected. In this paper, we develop and apply algorithms for the central navigation and planning problems on ship hulls. These divide into two classes, suitable for the open, forward parts of a typical monohull, and for the complex areas around the shafting, propellers and rudders. On the open hull, we have integrated acoustic and visual mapping processes to achieve closed-loop control relative to features such as weld-lines and biofouling. In the complex area, we implemented new large-scale planning routines so as to achieve full imaging coverage of all the structures, at a high resolution. We demonstrate our approaches in recent operations on naval ships.United States. Office of Naval Research (Grant N00014-06-10043)United States. Office of Naval Research (Grant N00014-07-1-0791

    Prenatal Prediction of Poor Maternal and Offspring Outcomes: Implications for Selection into Intensive Parent Support Programs

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    This study examined the predictive ability of mother’s age, antenatal depression, education, financial difficulties, partner status, and smoking for a range of poor maternal and offspring outcomes assessed up to 61 months postnatally. Outcomes obtained from the Avon Longitudinal Study of Parents and Children (ALSPAC) were maternal postnatal depression at 8 weeks (n = 10,070), never breastfeeding (n = 7,976), feelings of poor attachment (n = 8,253) and hostility (n = 8,159) at 47 months, and not in employment, education or training (NEET, n = 8,265) at 61 months. Only a small proportion of women with each outcome were aged less than 20 years when they were pregnant. At least half of the women experiencing these outcomes, and up to 74.7% of women with postnatal depression, could be identified if they had at least one of the predictors measured during pregnancy (age < 20, depression, education less than O level, financial difficulties, no partner, or smoking). Model discrimination was poor using maternal age only (area under the receiver operator characteristic (AUROC) curve approximately 0.52), except for never breastfeeding (0.63). Discrimination improved (AUROC: 0.80, 0.69, 0.62, 0.60, 0.66 for depression, never breastfeeding, poor attachment, hostility and NEET, respectively) when all six predictors were included in the model. Calibration improved for all outcomes with the model including all six predictors, except never breastfeeding where even age alone demonstrated good calibration. Factors other than young maternal age, including education, smoking and depression during pregnancy should be considered in identifying women and their offspring likely to benefit from parenting support interventions

    Natural history of Arabidopsis thaliana and oomycete symbioses

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    Molecular ecology of plant–microbe interactions has immediate significance for filling a gap in knowledge between the laboratory discipline of molecular biology and the largely theoretical discipline of evolutionary ecology. Somewhere in between lies conservation biology, aimed at protection of habitats and the diversity of species housed within them. A seemingly insignificant wildflower called Arabidopsis thaliana has an important contribution to make in this endeavour. It has already transformed botanical research with deepening understanding of molecular processes within the species and across the Plant Kingdom; and has begun to revolutionize plant breeding by providing an invaluable catalogue of gene sequences that can be used to design the most precise molecular markers attainable for marker-assisted selection of valued traits. This review describes how A. thaliana and two of its natural biotrophic parasites could be seminal as a model for exploring the biogeography and molecular ecology of plant–microbe interactions, and specifically, for testing hypotheses proposed from the geographic mosaic theory of co-evolution

    Parent and child interactions with two contrasting anti-obesity advertising campaigns: A qualitative analysis

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    Background: Social marketing has been proposed as a framework that may be effectively used to encourage behaviour change relating to obesity. Social advertising (or mass media campaigning) is the most commonly used social marketing strategy to address the issue of obesity. While social advertising has the potential to effectively communicate information about obesity, some argue that the current framing and delivery of these campaigns are ineffective, and may cause more harm than good. Methods: We used a qualitative advertising reception study. 150 family groups (comprised of 159 parents and 184 children) were shown two Australian government anti-obesity advertisements: Measure Up (focused on problems associated with obesity) and Swap It (focused on solutions for obesity). Families were engaged in a discussion about the visual appeals, verbal messages and their perceptions about the impact of the advertisements on behavioural change. Open coding techniques and a constant comparative method of analysis was used to interpret the data.Results: Many parents had strong personal resonance with the visual imagery within the campaigns. While Swap It had strong ‘likeability’ with children, many children believed that the messages about overweight and obesity were less personally relevant because they did not perceive themselves to be overweight. The content and delivery style of the verbal messages (the serious risk focused message in Measure Up compared to the upbeat, fun practical message in Swap It) influenced how different audiences (parents and children) interpreted the information that was presented. Parents assimilated practical and instructive messages, while children assimilated messages about weight loss and weight gain. Parents and children recognised that the campaigns were asking individuals to take personal responsibility for their weight status, and were at times critical that the campaigns did not tackle the broader issues associated with the causes and consequences of obesity. The lack of practical tools to encourage behavioural change was a key barrier for obese parents. Conclusions: Well-funded, targeted social marketing campaigns will play an important role in the prevention and management of obesity. It is important that these campaigns are comprehensively evaluated and are backed up with structural supports to enable and encourage population subgroups to act upon messages

    Induction of humoral immune response to multiple recombinant Rhipicephalus appendiculatus antigens and their effect on tick feeding success and pathogen transmission

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    BACKGROUND: Rhipicephalus appendiculatus is the primary vector of Theileria parva, the etiological agent of East Coast fever (ECF), a devastating disease of cattle in sub-Saharan Africa. We hypothesized that a vaccine targeting tick proteins that are involved in attachment and feeding might affect feeding success and possibly reduce tick-borne transmission of T. parva. Here we report the evaluation of a multivalent vaccine cocktail of tick antigens for their ability to reduce R. appendiculatus feeding success and possibly reduce tick-transmission of T. parva in a natural host-tick-parasite challenge model. METHODS: Cattle were inoculated with a multivalent antigen cocktail containing recombinant tick protective antigen subolesin as well as two additional R. appendiculatus saliva antigens: the cement protein TRP64, and three different histamine binding proteins. The cocktail also contained the T. parva sporozoite antigen p67C. The effect of vaccination on the feeding success of nymphal and adult R. appendiculatus ticks was evaluated together with the effect on transmission of T. parva using a tick challenge model. RESULTS: To our knowledge, this is the first evaluation of the anti-tick effects of these antigens in the natural host-tick-parasite combination. In spite of evidence of strong immune responses to all of the antigens in the cocktail, vaccination with this combination of tick and parasite antigens did not appear to effect tick feeding success or reduce transmission of T. parva. CONCLUSION: The results of this study highlight the importance of early evaluation of anti-tick vaccine candidates in biologically relevant challenge systems using the natural tick-host-parasite combination
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