5,282 research outputs found

    Adaptive colour change and background choice behaviour in peppered moth caterpillars is mediated by extraocular photoreception

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    Light sensing by tissues distinct from the eye occurs in diverse animal groups, enabling circadian control and phototactic behaviour. Extraocular photoreceptors may also facilitate rapid colour change in cephalopods and lizards, but little is known about the sensory system that mediates slow colour change in arthropods. We previously reported that slow colour change in twig-mimicking caterpillars of the peppered moth (Biston betularia) is a response to achromatic and chromatic visual cues. Here we show that the perception of these cues, and the resulting phenotypic responses, does not require ocular vision. Caterpillars with completely obscured ocelli remained capable of enhancing their crypsis by changing colour and choosing to rest on colour-matching twigs. A suite of visual genes, expressed across the larval integument, likely plays a key role in the mechanism. To our knowledge, this is the first evidence that extraocular colour sensing can mediate pigment-based colour change and behaviour in an arthropod

    Installation of insecticide-treated durable wall lining: evaluation of attachment materials and product durability under field conditions.

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    BACKGROUND: Insecticide-treated durable wall lining (DL) is a new method of vector control designed to supplement LLINs and overcome two inherent limitations of LLINs and IRS: nightly behavioural compliance and short residual activity, respectively. DL is a deltamethrin-treated polyethylene material, which when used to cover interior house walls, functions as long-lasting IRS. Because the DL concept anticipates minimal upkeep, a primary challenge is how to guarantee correct household installation and in situ longevity for several years. Field trials were undertaken on various wall surfaces in Ghana to identify a logistically feasible, durable and re-usable method for DL wall attachment and to pilot new methods for assessing DL durability. METHODS: Over fifty-five candidate attachment or fixing products, including mechanical fasteners, material anchors and adhesives, were evaluated for their ability to tolerate static loads (simulating long-term installation) and short-term heavy weights (imitating shock damage). Attachment products were also scored using qualitative logistical and feasibility criteria, including ease of preparation, grip of fixing to DL and possibility of re-use. RESULTS: The stress tests provided a standardised, reproducible and reliable system for assessing fixing effectiveness and DL durability, with 64% (14/22) of adhesives and 15% (2/13) of mechanical fasteners failing to meet the minimum requirements of attaching DL to mud walls for set time periods. For most fixings, less outward load (0.2-8.0 kg) was required to detach DL from the wall, compared to downward load (0.2-19.2 kg). Fixings were better able to grip DL onto concrete than clay surfaces. Using a plastic nail cap to increase DL attachment area greatly improved grip and outward load tolerance, more so than varying nail size, length or texture. CONCLUSIONS: Based on a series of systematic stress tests, optimized fixing products for polyethylene DL wall attachment were identified. In parallel, a detailed and adaptable method of DL household installation was developed for routine deployment in malaria endemic areas. These standardized stress tests will form the basis for comparative evaluations of new types of DL textile, which incorporate non-pyrethroid insecticides to control malaria transmitted by resistant mosquito populations

    Prevalence of working smoke alarms in local authority inner city housing: randomised controlled trial

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    Objectives To identify which type of smoke alarm is most likely to remain working in local authority inner city housing, and to identify an alarm tolerated in households with smokers. Design Randomised controlled trial. Setting Two local authority housing estates in inner London. Participants 2145 households. Intervention Installation of one of five types of smoke alarm (ionisation sensor with a zinc battery; ionisation sensor with a zinc battery and pause button; ionisation sensor with a lithium battery and pause button; optical sensor with a lithium battery; or optical sensor with a zinc battery). Main outcome measure Percentage of homes with any working alarm and percentage in which the alarm installed for this study was working after 15 months. Results 54.4% (1166/2145) of all households and 45.9% (465/1012) of households occupied by smokers had a working smoke alarm. Ionisation sensor, lithium battery, and there being a smoker in the household were independently associated with whether an alarm was working (adjusted odds ratios 2.24 (95% confidence interval 1.75 to 2.87), 2.20 (1.77 to 2.75), and 0.62 (0.52 to 0.74)). The most common reasons for non-function were missing battery (19%), missing alarm (17%), and battery disconnected (4%). Conclusions Nearly half of the alarms installed were not working when tested 15 months later. Type of alarm and power source are important determinants of whether a household had a working alarm

    Fishing for evidence of impact

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    In this article Gill Rowland, Hazel King, Penny Webb, Alison Cogger and Karen Vincent use seafaring imagery to portray a research project focussed on enriching mentoring within a school university initial teaching training partnership. They report on the professional development benefits gained from use of their framework for both school based mentors and university-based mentors

    Diagnostic accuracy of PAT-POPS and ManChEWS for admissions of children from the emergency department

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    Background The Pennine Acute Trust (PAT) Paediatric Observation Priority Score (PAT-POPS) is a specific emergency department (ED) physiological and observational aggregate scoring system, with scores of 0–18. A higher score indicates greater likelihood of admission. The Manchester Children’s Early Warning System (ManChEWS) assesses six physiological observations to create a trigger score, classified as Green, Amber or Red. Methods Prospectively collected data were used to calculate PAT-POPS and ManChEWS on 2068 patients aged under 16 years (mean 5.6 years, SD 4.6) presenting over 1 month to a UK District General Hospital Paediatric ED. Receiver operating characteristics (ROC) comparison, using STATA V.13, was used to investigate the ability of ManChEWS and PAT-POPS to predict admission to hospital within 72 h of presentation to the ED. Results Comparison of the area under the ROC curve indicates that the ManChEWS ROC is 0.67 (95% CI 0.64 to 0.70) and the PAT-POPS ROC is 0.72 (95% CI 0.68 to 0.75). The difference is statistically significant. At a PAT-POPS cut-off of ≄2, 80% of patients had their admission risk correctly classified ( positive likelihood ratio 3.40, 95% CI 2.90 to 3.98) whereas for ManChEWS with a cut off of ≄Amber only 71% of patients were correctly classified ( positive likelihood ratio 2.18, 95% CI 1.94 to 2.45). Conclusions PAT-POPS is a more accurate predictor of admission risk than ManChEWS. Replacing ManChEWS with PAT-POPS would appear to be clinically appropriate in a paediatric ED. This needs validation in a multicentre study

    Impact of soil conditions on hydrology and water quality for a brown clay in the north-eastern cereal zone of Australia

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    Hydrology and water quality impacts of alternative land management practices are poorly quantified for semi-arid environments in the northern Australia cropping zone, yet wide-scale changes in tillage practices and land use were being recommended based on experience from other environments. The objective of this study was to explore changes in soil profile and catchment hydrology and water quality associated with different soil surface conditions created by different tillage and grazing practices. Soil water, runoff, and suspended sediment concentrations were monitored on 4 contour bay catchments over an 18-year period. Soil conditions were described by soil moisture, soil cover, and surface roughness in order to explore functional relationships between management, hydrology, and water quality. The site was chosen to represent the drier margins of cropping in southern Queensland where clay soils with high water-holding capacity, in conjunction with fallowing to store water for later crop growth, are an essential risk management tool. Accumulation of soil water in fallows was inefficient, with fallow efficiencies ranging from 7 to 40% due to high evaporation and runoff losses. Runoff amount was determined by soil water content, which was strongly influenced by antecedent rainfall, water use, and evaporation patterns. Surface cover and roughness had subtle influences on runoff, and a greater effect on suspended sediment concentration. Runoff and suspended sediment losses were considerably lower under pasture than cropping. A participative approach between farmers and scientists was demonstrated to be an efficient method to carry out an extensive and long-term catchment study at a remote location. This study provides benchmark data for future hydrologic and water quality investigations. © CSIRO 2009

    Student conceptions about energy transformations: progression from general chemistry to biochemistry

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    Students commencing studies in biochemistry must transfer and build on concepts they learned in chemistry and biology classes. It is well established, however, that students have difficulties in transferring critical concepts from general chemistry courses; one key concept is “energy.” Most previous work on students’ conception of energy has focused on their understanding of energy in the context of physics (including the idea of “work”) and/or their understanding of energy in classical physical and inorganic chemistry contexts (particularly Gibbs Free Energy changes, the second law of thermodynamics, and equilibrium under standard conditions within a closed system). For biochemistry, students must go beyond those basic thermodynamics concepts of work, standard energy changes, and closed systems, and instead they must consider what energy flow, use, and transformation mean in living, open, and dynamic systems. In this study we explored students’ concepts about free energy and flow in biological chemical reactions and metabolic pathways by surveys and in-depth interviews. We worked with students in general chemistry classes and biochemistry courses in both an Australian and a US tertiary institution. We address three primary questions (i) What are the most common alternative conceptions held by students when they explain energy-related phenomena in biochemistry?, (ii) What information do students transfer from introductory chemistry and biology when they are asked to consider energy in a biological reaction or reaction pathway?, and (iii) How do students at varying levels of competence articulate their understandings of energy in pathways and biological reactions? The answers to these questions are used to build a preliminary learning progression for understanding “energy” in biochemistry. We also propose crucial elements of content knowledge that instructors could apply to help students better grasp this threshold concept in biochemistry
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