125 resultados para Simulated experiment
Resumo:
Objective: We explored whether readers can understand key messages without having to read the full review, and if there were differences in understanding between various types of summary.
Design: A randomised experiment of review summaries which compared understanding of a key outcome.
Participants: Members of university staff (n = 36).
Setting: Universities on the island of Ireland.
Method: The Cochrane Review chosen examines the health impacts of the use of electric fans during heat waves. Participants were asked their expectation of the effect these would have on mortality. They were then randomly assigned a summary of the review (i.e. abstract, plain language summary, podcast or podcast transcription) and asked to spend a short time reading/listening to the summary. After this they were again asked about the effects of electric fans on mortality and to indicate if they would want to read the full Review.
Main outcome measure: Correct identification of a key review outcome.
Results: Just over half (53%) of the participants identified its key message on mortality after engaging with their summary. The figures were 33% for the abstract group, 50% for both the plain language and transcript groups and 78% for the podcast group.
Conclusions: The differences between the groups were not statistically significant but suggest that the audio summary might improve knowledge transfer compared to written summaries. These findings should be explored further using a larger sample size and with other reviews.
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This article addresses gender differences in laughter and smiling from an evolutionary perspective. Laughter and smiling can be responses to successful display behavior or signals of affiliation amongst conversational partners—differing social and evolutionary agendas mean there are different motivations when interpreting these signals. Two experiments assess perceptions of genuine
and simulated male and female laughter and amusement social signals. Results show male simulation can always be distinguished. Female simulation is more complicated as males seem to distinguish cues of simulation yet judge simulated signals to be genuine. Females judge other female’s genuine signals to have higher levels of simulation. Results highlight the importance of laughter and smiling in human interactions, use of dynamic stimuli, and using multiple methodologies to assess perception.
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Shape memory NiTi alloys have been used extensively for medical device applications such as orthopedic, dental, vascular and cardiovascular devices on account of their unique shape memory effect (SME) and super-elasticity (SE). Laser welding is found to be the most suitable method used to fabricate NiTi-based medical components. However, the performance of laser-welded NiTi alloys under corrosive environments is not fully understood and a specific focus on understanding the corrosion fatigue behaviour is not evident in the literature. This study reveals a comparison of corrosion fatigue behaviour of laser-welded and bare NiTi alloys using bending rotation fatigue (BRF) test which was integrated with a specifically designed corrosion cell. The testing environment was Hanks’ solution (simulated body fluid) at 37.5oC. Electrochemical impedance spectroscopic (EIS) measurement was carried out to monitor the change of corrosion resistance at different periods during the BRF test. Experiments indicate that the laser-welded NiTi alloy would be more susceptible to the corrosion fatigue attack than the bare NiTi alloy. This finding can serve as a benchmark for the product designers and engineers to determine the factor of safety of NiTi medical devices fabricated using laser welding.
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The First World War hit Germany severely, particularly the agricultural sector, because the outbreak came unexpected and its duration exceeded all expectations. Many resources necessary for agricultural production were required by the war economy and led to shortages and shrinking supplies. Many agricultural laborers were drafted and the blockade imposed by the allies prevented Germany from a great deal of imports. As a consequence, the nutritional situation was devastating, particularly after 1916, and hit all groups of the German society. The period under observation provides one of most drastic natural experiments in the 20th century. This study uses anthropometric data from German soldiers who served in the Second World War to trace living standards between the 1900s and the 1920s. In contrast to other approaches, this paper is able to distinguish between social groups by occupation, religious denominatio\n, regional origin, and city size. The results suggest that although all social strata were hit by famine conditions, the height of farmers, urban citizens, Catholics, and especially individuals born in the highly integrated food-import regions along the coast and the banks of the Rhine declined most.
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Wear and corrosion of metal-on-metal hip replacements results in wear debris and metal-ion release in vivo, which may subsequently cause pain and hypersensitivity for patients. Retrieved metal-on-metal hip replacements have revealed that two-body sliding wear and three-body abrasive wear are the predominant wear mechanisms. However, there is a lack of understanding of the combined effects of wear/corrosion, especially the effect of abrasion-corrosion.
This study investigates the sliding-corrosion and abrasion-corrosion performance of a cast CoCrMo alloy in simulated hip joint environments using a microabrasion rig integrated with an electrochemical cell. Tests have been conducted in 0.9% NaCl, phosphate buffered saline solution, 25% and 50% bovine serum solutions with 0 or 1 g cm(-3) SiC at 37 degrees C. Experimental results reveal that under abrasion-corrosion test conditions, the presence of proteins increased the total specific wear rate. Conversely, electrochemical noise measurements indicated that the average anodic current levels were appreciably lower for the proteinaceous solutions when compared with the inorganic solutions. A severely deformed nanocrystalline layer was identified immediately below the worn surface for both proteinaceous and inorganic solutions. The layer is formed by a recrystallisation process and/or a strain-induced phase transformation that occurs during microabrasion-corrosion. (C) 2008 Elsevier Ltd. All rights reserved.
Resumo:
The abrasion seen on some of the retrieved CoCrMo hip joints has been reported to be caused by entrained hard particles in vivo. However, little work has been reported on the abrasion mechanisms of CoCrMo alloy in simulated body environments. Therefore. this study covers the mapping of micro-abrasion wear mechanisms of cast CoCrMo induced by third body hard particles under a wide range of abrasive test conditions. This study has a specific focus on covering the possible in vivo wear modes seen on metal-on-metal (MoM) surfaces. Nano-indentation and nano-scratch tests were also employed to further investigate the secondary wear mechanisms-nano-scale material deformation that involved in micro-abrasion processes. This work addresses the potential detrimental effects of third body hard particles in vivo such as increased wear rates (debris generation) and corrosion (metal-ion release). The abrasive wear mechanisms of cast CoCrMo have been investigated under various wear-corrosion conditions employing two abrasives, SiC (similar to 4 mu m) and Al(2)O(3) (similar to 1 mu m), in two test solutions, 0.9% NaCl and 25% bovine serum. The specific wear rates, wear mechanisms and transitions between mechanisms are discussed in terms of the abrasive size, volume fraction and the test solutions deployed. The work shows that at high abrasive volume fractions, the presence of protein enhanced the wear loss due to the enhanced particle entrainment, whereas at much lower abrasive volume fractions, protein reduced the wear loss by acting as a boundary lubricant or rolling elements which reduced the abrasivity (load per particle) of the abrasive particles. The abrasive wear rate and wear mechanisms of the CoCrMo are dependent on the nature of the third body abrasives, their entrainment into the contact and the presence of the proteins. (C) 2009 Elsevier B.V. All rights reserved.
Resumo:
Some retrieved CoCrMo hip implants have shown that abrasive wear is one of the possible wear mechanisms invoked within such joints. To date, little work has focused on the third body abrasion of CoCrMo and therefore there is a general lack of understanding of the effect of abrasive size and volume concentration on the tribo-corrosion performance of the CoCrMo alloys. The present work assessed the tribo-corrosion behaviour of cast CoCrMo (F-75) under various abrasion-corrosion conditions by using a modified microabrasion tester incorporating a three-electrode electrochemical cell. The effects of reduced abrasive size/hardness and volume concentration, as well as the role of proteins on the tribo-corrosion performance of the cast CoCrMo alloy were addressed. The correlation between electrochemical and mechanical processes for different abrasion-corrosion test conditions has been discussed in detail. Results show that the reduction in abrasive size and volume concentration can significantly affect the abrasion-corrosion wear mechanisms and the wear-induced corrosion response of the material. The finding of this study implies that the smaller/softer third body particles generated in vivo could also result in significant wear-induced corrosion and therefore potential metal ion release, which could be potentially detrimental to both the patient health and the life span of the implants. © 2009 Elsevier Ltd. All rights reserved.
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This chapter explores the history of active citizenship education in English schools in relation to the more established tradition of service learning in the US.
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A 2D sandbox style experiment was developed to compare the results of numerical modelling to physical testing for saltwater intrusion in homogeneous and heterogeneous aquifers. The sandbox consisted of a thin central viewing chamber filled with glass beads of varying diameters (780μm, 1090μm and 1325μm) under fully saturated conditions. Dyed saltwater (SW) was introduced at the side boundary and a head difference imposed across the porous media. Images of the SW wedge were recorded at intervals in order to assess the suitability of the numerical models predictions of transient SW intrusion. Numerical modelling of the experimental cases were simulated using SUTRA. Two main parameters were chosen to express the condition of the intruding SW wedge at each recorded time step; the toe penetration length (TL) and the width of the mixing zone (WMZ). The WMZ was larger under transient conditions in the heterogeneous case, while the TL was longer for the homogeneous case. The increased variability in the flow field fo the heterogeneous case resulted in increased dispersion, and thus, increased WMZ.
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Newly qualified nurses have been educated and assessed as being proficient carrying out certain procedures ,one such insertion of nasogastric feeding tube. Link between theory and practice will be explored. Highlighting the value of low fidelity simulation and peer assessment to enhance skills and competencies.
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Simulation learning is used in several health disciplines. The Department of Health defines simulation as ‘any reproduction or approximation of a real event, process or set of conditions or problems’.