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101.
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In this paper, we present an on-chip hand-powered membrane pump using a robust patient-to-chip syringe interface. This approach enables safe sample collection, sample containment, integrated sharps disposal, high sample volume capacity, and controlled downstream flow with no electrical power requirements. Sample is manually injected into the device via a syringe and needle. The membrane pump inflates upon injection and subsequently deflates, delivering fluid to downstream components in a controlled manner. The device is fabricated from poly(methyl methacrylate) (PMMA) and silicone, using CO2 laser micromachining, with a total material cost of ∼0.20 USD/device. We experimentally demonstrate pump performance for both deionized (DI) water and undiluted, anticoagulated mouse whole blood, and characterize the behavior with reference to a resistor-capacitor electrical circuit analogy. Downstream output of the membrane pump is regulated, and scaled, by connecting multiple pumps in parallel. In contrast to existing on-chip pumping mechanisms that typically have low volume capacity (∼5 μL) and sample volume throughput (∼1–10 μl/min), the membrane pump offers high volume capacity (up to 240 μl) and sample volume throughput (up to 125 μl/min). 相似文献
103.
This study was designed to examine the relationship between syntactic awareness and reading performance. A major concern was to provide an estimate of the effect of syntactic training that was not confounded with training that focused on semantic features of words. The training exercises used in the study focused on all levels of syntactic awareness in order that the effect of such training could be assessed on students’ performance on tasks that tapped each of the levels. Results of this study showed that syntactic awareness could be improved through training. The effect was stable, being apparent at the two post-test times. However, no evidence was found for a systematic effect of improved syntactic awareness on reading ability. Moreover, syntactic training did not show any greater effect than no treatment or semantic training on children’s grammatic comprehension, their ability to use fix-up strategies, or on their general reading ability score. Training had a different impact on the accuracy of oral reading for the syntactic and semantic training groups. Thus, in terms of the developmental sequence of syntactic awareness proposed by Gombert (1992), children trained in the cloze procedure improved at the two highest levels, whilst showing neither a corresponding change in the lower levels of awareness, nor improved functional reading performance. 相似文献
104.
The knowledge paradox suggests that high levels of investment in new knowledge do not necessarily and automatically generate the anticipated levels of competitiveness of growth. In particular, knowledge investments do not automatically translate into balanced growth and competitiveness. The purpose of this paper is to explain why knowledge investments are inherently unbalanced, so that the competitiveness and growth ensuing from knowledge are not equally spread across individuals, firms, and spatial units of observation, such as regions and countries. Based on a data set linking entrepreneurial activity to growth within the context of German regions, this paper shows that entrepreneurship serves a conduit of knowledge spillovers. 相似文献
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Max Visser 《Learning Inquiry》2008,2(2):127-137
To survive in and adapt to dynamic, turbulent, and complex environments, organizations need to engage in learning. This truism is particularly relevant for army organizations in times of war and armed conflict. In this article a case of army operations during World War II is analyzed on the basis of ?rtenblad’s integrated model of the learning organization and Argyris and Schön’s theory of action approach. Among others, it is found that survival of and adaptation to combat conditions is possible through single-loop learning, provided that this learning takes place in an open and productive learning climate. This and other conclusions have important implications for theory and practice of organizational learning under conditions of hierarchy and discipline. 相似文献
107.
The main factors associated with technology integration have been the subject of research for over a decade. However, the conditions which sustain technological developments have been less frequently investigated. This paper explores this issue in the context of the use of videoconferencing in schools in England. The research took a multiple case-study approach by returning to schools with a reputation for demonstrating innovative policy and practice in videoconferencing, which were the subject of an earlier investigation. Analysis of developments in the interim five-year period led to the construction of a five-level typology of change. Further analysis identified critical dimensions associated with the sustainability of videoconferencing. These included technical and structural factors, as well as policy frameworks and personnel status. The perceived usefulness and relevance of videoconferencing as a learning technology emerges as a central determinant of sustainability, with the conclusion that for policymakers and schools, videoconferencing has become an ‘orphan’ technology. 相似文献
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Anton E. Lawson 《科学教学研究杂志》1986,23(6):503-522
Grossberg's neural modeling principles of learning, perception, cognition, and motor control are presented as the basis for construction of a neurological model of sensory-motor problem solving. The pattern of problem solving is assumed to be universal, thus is sought in the higher-order shift from the child's use of an additive strategy to the adolescent's use of a proportions strategy to solve the Pouring Water Task (Suarez and Rhonheimer, 1974). Possible neurological principles involved in this shift and in the process of psychological equilibration are discussed as are possible educational implications. 相似文献