2,535 research outputs found

    Putting the horse before the cart: formulating and exploring methods for studying cognitive technology

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    The First International Conference on Cognitive Technology (CT'95, Hong Kong, 1995) explored a radically new way of thinking about the impact computer technology has on humans, especially on the human mind. Our main aim at that time was a consideration of these effects with respect to rendering the interface between people and computers more humane. And we exemplified our approach by pointing to existing trends and tendencies in the vast new loosely organized field of research often referred to as `HCI' (`human computer interaction'; the replacement for the politically and factually `incorrect' MMI, `man machine interface')published_or_final_versio

    K-5 Teachers' Uses of Levels of Abstraction Focusing on Design

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    Recent research with middle school and university students highlights two factors that contribute to programming success: 1) understanding the level of abstraction that you are working at, and 2) being able to move between levels. In this qualitative study, we explored levels of abstraction, and particularly the design level,with five K-5 teachers. Here we outline 11 main findings. The teachers interviewed use the design level for both programming and writing. However, the two expert computing teachers have a far greater depth of understanding of the opportunities for the use of the design level, supporting pupils to understand the level they are working at and helping them move between levels of abstraction by using designs in novel ways. Further work is needed to investigate whether our results are generalisable. Further exploration of levels of abstraction and particularly how the design level helps K-5 learners learn to program, in the same way, that planning supports novices learning to write, is warranted

    Abstraction in action: K-5 teachers' uses of levels of abstraction, particularly the design level, in teaching programming

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    Research indicates that understanding levels of abstraction (LOA) and being able to move between the levels is essential to programming success. For K-5 contexts LOA levels have been named: problem, design, code and running the code. In a qualitative exploratory study, five K-5 teachers were interviewed on their uses of LOA, particularly the design level, in teaching programming and other subjects. Using PCK elements to analyse responses, the teachers interviewed used design as an instructional strategy and for assessment. The teachers used design as an aide memoire and the expert teachers used design: as a contract for pair-programming; to work out what they needed to teach; for learners to annotate with code snippets (to transition across LOA); for learners to self-assess and to assess ‘do-ability’. The teachers used planning in teaching writing to scaffold learning and promote self-regulation revealing their insight in student understanding. One issue was of the teachers' knowledge of terms including algorithm and code; a concept of ‘emergent algorithms’ is proposed. Findings from the study suggest design helps learners learn to program in the same way that planning helps learners learn to write and that LOA, particularly the design level, may provide an accessible exemplar of abstraction in action. Further work is needed to verify whether the study's results are generalisable more widely

    Clinical and cost effectiveness of mechanical support for severe ankle sprains: design of a randomised controlled trial in the emergency department [ISRCTN 37807450]

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    Background The optimal management for severe sprains (Grades II and III) of the lateral ligament complex of the ankle is unclear. The aims of this randomised controlled trial are to estimate (1) the clinical effectiveness of three methods of providing mechanical support to the ankle (below knee cast, Aircast® brace and Bledsoe® boot) in comparison to Tubigrip®, and (2) to compare the cost of each strategy, including subsequent health care costs. Methods/design Six hundred and fifty people with a diagnosis of severe sprain are being identified through emergency departments. The study has been designed to complement routine practice in the emergency setting. Outcomes are recovery of mobility (primary outcome) and usual activity, residual symptoms and need for further medical, rehabilitation or surgical treatment. Parallel economic and qualitative studies are being conducted to aid interpretation of the results and to evaluate the cost-effectiveness of the interventions. Discussion This paper highlights the design, methods and operational aspects of a clinical trial of acute injury management in the emergency department

    Scallop swimming kinematics and muscle performance: modelling the effects of "within-animal" variation in temperature sensitivity

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    Escape behaviour was investigated in Queen scallops (Aequipecten opercularis) acclimated to 5, 10 or 15 degrees C and tested at their acclimation temperature. Scallops are active molluscs, able to escape from predators by jet-propelled swimming using a striated muscle working in opposition to an elastic hinge ligament. The first cycle of the escape response was recorded using high-speed video ( 250 Hz) and whole-animal velocity and acceleration determined. Muscle shortening velocity, force and power output were calculated using measurements of valve movement and jet area, and a simple biomechanical model. The average shortening speed of the adductor muscle had a Q(10) of 2.04, significantly reducing the duration of the jetting phase of the cycle with increased temperature. Muscle lengthening velocity and the overall duration of the clap cycle were changed little over the range 5 - 15 degrees C, as these parameters were controlled by the relatively temperature-insensitive, hinge ligament. Improvements in the average power output of the adductor muscle over the first clap cycle ( 222 vs. 139 W kg(-1) wet mass at 15 and 5 degrees C respectively) were not translated into proportional increases in overall swimming velocity, which was only 32% higher at 15 degrees C ( 0.37m s(-1)) than 5 degrees C (0.28 m s(-1))

    Abstraction and Common Classroom Activities

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    In popularizing computational thinking, Wing notes that ‘abstraction is described as underlying computational thinking and computational thinking is described as fundamental to computing.’ Emerging curricular now require educators to incorporate computational thinking and abstraction into their teaching. Many refer to Piaget’s work as evidence of an age-related ceiling preventing younger pupils from being able to abstract. However, more recent evidence suggests that pupils use elements of abstraction in their general process of learning, and that the skill of abstraction can be explicitly taught. We draw on personal classroom experience to illustrate the points made in the literature. Common classroom activities such as using labelled diagrams, concept maps and storyboards are aligned to features of abstraction. We argue that abstraction can and should be taught to young pupils

    Estimating risk of C. difficile transmission from PCR positive but cytotoxin negative cases

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    Background: The use of molecular methods to diagnose Clostridium difficile infection (CDI) has improved diagnostic yield compared to conventional methods. However, PCR testing can detect colonization and has introduced several practical challenges pertaining to need for treatment and isolation of cases. Methods: For all new cases detected by real-time PCR, concurrent cytotoxin assay was performed and genetic characterization with MLVA (multi-locus variable number tandem repeat analysis) was done to determine relatedness. We used PCR cycle threshold (Ct) of detection as surrogate marker for bacterial burden in stool. Results: Overall, 54 cases of CDI were detected during the study period. 42 were concurrently tested by CYT and characterized by MLVA. MLVA analysis revealed marked genetic diversity with no ongoing outbreaks; four cases were due to NAP1 strain. CYT-/PCR + cases had a higher median Ct value of detection compared to CYT+/PCR + cases (28.2 vs 22.5; p = 0.01). Among 25 strains that were genetically related, 9/11 isolates in this dominant cluster were positive by CYT compared to 4/14 in non-dominant clusters (p = 0.02). Conclusion: CYT-/PCR+ cases contribute to hospital based transmission. However, the risk of transmission of C. difficile from CYT +/PCR+ cases may be higher than those that are CYT-/PCR+. © 2014 Kamboj et al

    Inhibition of HIV-1 gene expression by Sam68ΔC: multiple targets but a common mechanism?

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    Two recent publications have explored the mechanisms by which a mutant of the host protein Sam68 blocks HIV-1 structural protein synthesis and expands its activity to encompass Nef. Although the two studies propose different mechanisms for the responses observed, it is possible that a common activity is responsible. Understanding how this Sam68 mutant discriminates among the multiple viral mRNAs promises to reveal unique properties of HIV-1 RNA metabolism

    Error growth in the Mesosphere and Lower Thermosphere Based on Hindcast Experiments in a Whole Atmosphere Model

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    The capability to forecast conditions in the mesosphere and lower thermosphere is investigated based on 30‐day hindcast experiments that were initialized bimonthly during 2009 and 2010. The hindcasts were performed using the Whole Atmosphere Community Climate Model with thermosphere‐ionosphere eXtension (WACCMX) with data assimilation provided by the Data Assimilation Research Testbed (DART) ensemble Kalman filter. Analysis of the WACCMX+DART hindcasts reveals several important features that are relevant to forecasting the middle atmosphere. The results show a clear dependence on spatial scale, with the slowest error growth occurring in the zonal mean and the fastest error growth occurring for small‐scale waves. The error growth rate is also found to be significantly greater in the upper mesosphere and lower thermosphere compared to in the upper stratosphere to lower mesosphere, suggesting that the forecast skill decreases with increasing altitude. The results demonstrate that the errors in the lower thermosphere reach saturation, on average, in less than 5 days, at least with the current version of WACCMX+DART. A seasonal dependency to the error growth is found at high latitudes in the Northern and Southern Hemispheres but not in the tropics or global average. We additionally investigate the error growth rates for migrating and nonmigrating atmospheric tides and find that the errors saturate after ∼5 days for tides in the lower thermosphere. The results provide an initial assessment of the error growth rates in the mesosphere and lower thermosphere and are relevant for understanding how whole atmosphere models can potentially improve space weather forecasting

    Major surgery in an osteosarcoma patient refusing blood transfusion: case report

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    We describe an unusual case of osteosarcoma in a Jehovah's Witness patient who underwent chemotherapy and major surgery without the need for blood transfusion. This 16-year-old girl presented with osteosarcoma of the right proximal tibia requiring proximal tibia resection, followed by endoprosthesis replacement. She was successfully treated with neoadjuvant chemotherapy and surgery with the support of haematinics, granulocyte colony-stimulating factor, recombinant erythropoietin and intraoperative normovolaemic haemodilution. This case illustrates the importance of maintaining effective, open communication and exploring acceptable therapeutic alternative in the management of these patients, whilst still respecting their beliefs
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