Extensional flow of blood analog solutions in microfluidic devices     

P. C. Sousa  F. T. Pinho  M. S. N. Oliveira    M. A. Alves 《Biomicrofluidics》2011,5(1)

In this study, we show the importance of extensional rheology, in addition to the shear rheology, in the choice of blood analog solutions intended to be used in vitro for mimicking the microcirculatory system. For this purpose, we compare the flow of a Newtonian fluid and two well-established viscoelastic blood analog polymer solutions through microfluidic channels containing both hyperbolic and abrupt contractions∕expansions. The hyperbolic shape was selected in order to impose a nearly constant strain rate at the centerline of the microchannels and achieve a quasihomogeneous and strong extensional flow often found in features of the human microcirculatory system such as stenoses. The two blood analog fluids used are aqueous solutions of a polyacrylamide (125 ppm w∕w) and of a xanthan gum (500 ppm w∕w), which were characterized rheologically in steady-shear flow using a rotational rheometer and in extension using a capillary breakup extensional rheometer (CaBER). Both blood analogs exhibit a shear-thinning behavior similar to that of whole human blood, but their relaxation times, obtained from CaBER experiments, are substantially different (by one order of magnitude). Visualizations of the flow patterns using streak photography, measurements of the velocity field using microparticle image velocimetry, and pressure-drop measurements were carried out experimentally for a wide range of flow rates. The experimental results were also compared with the numerical simulations of the flow of a Newtonian fluid and a generalized Newtonian fluid with shear-thinning behavior. Our results show that the flow patterns of the two blood analog solutions are considerably different, despite their similar shear rheology. Furthermore, we demonstrate that the elastic properties of the fluid have a major impact on the flow characteristics, with the polyacrylamide solution exhibiting a much stronger elastic character. As such, these properties must be taken into account in the choice or development of analog fluids that are adequate to replicate blood behavior at the microscale.  相似文献   

Maintaining quality document delivery service with off-site storage facilities.     

Melanie J Norton  Adam S Vardaman 《Journal of the Medical Library Association》2005,93(3):394-397

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Karl Pearson and statistics: the social origins of scientific innovation     

Norton BJ 《Social studies of science》1978,8(1):3-34

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‘Now that’s the feedback I want!’ Students’ reactions to feedback on graded work and what they do with it     

Edd Pitt  Lin Norton 《Assessment & Evaluation in Higher Education》2017,42(4):499-516

Since the introduction of the National Student Survey (NSS) in 2005, like many other institutions, the university where this study took place has expended substantial effort in improving the quality of feedback to students. However, despite much research, changes in pedagogical approaches and shifts in conceptual understanding related to feedback practice, assessment and feedback still receive the lowest satisfaction ratings in the NSS. Lecturers are discouraged when students fail to take note of their feedback, or sometimes do not collect assignments that have been marked. Understanding why feedback is not always acted upon remains an important area for researchers. This paper reports on an in-depth interview study with 14 final year undergraduates, reflecting on their perceptions of feedback written on marked assignments, by selecting examples of what they considered to be ‘good’ and ‘bad’ work. Findings suggested that emotional reactions play a significant part in determining how students will act on the feedback they receive, and the concept of ‘emotional backwash’ is introduced.  相似文献   

Lecturers’ views of assessment design,marking and feedback in higher education: a case for professionalisation?     

Lin Norton  Sarah Floyd  Bill Norton 《Assessment & Evaluation in Higher Education》2019,44(8):1209-1221

Abstract

Research on professional assessment practice in higher education does not always take account of lecturers’ perceptions and experiences, or their disciplinary context. This questionnaire study was designed to explore lecturers’ views about three inter-related elements of professional assessment practice: assessment design, marking and feedback. It consisted of two questionnaires: the Assessment Design Inventory (ADI), previously published, and the Assessment, Marking and Feedback Inventory (AMFI) which was newly developed for this study. The two main purposes of the research were to: i) establish the validity of these two questionnaires as research tools, ii) explore the existence of professional practice in assessment and analyse any perceived hindrances as well as possible effects of participants’ subject discipline. 356 lecturers from two UK universities, with a range of teaching experience and representing soft and hard disciplines, took part. Results indicated that the ADI and the AMFI were robust instruments. Findings showed evidence of assessment professionalism, but also some areas where it was lacking, together with a perceived need for formal training. Participants recognised that there were certain hindrances in putting their pedagogical beliefs into practice. The implications of this study are discussed in terms of advancing the sector’s understanding of assessment professionalism.  相似文献   

Can students be helped to learn how to learn? An evaluation of an Approaches to Learning programme for first year degree students     

Linda S. Norton  Catherine M. Crowley 《Higher Education》1995,29(3):307-328

This study reports on an attempt to improve the quality of student learning by integrating an Approaches to Learning programme, consisting of 8 workshops, into the first year Psychology curriculum. Written accounts of students' conceptions of learning were collected at the beginning and end of the programme. Content analysis showed that there was a significant shift from naive to more sophisticated conceptions (29% to 60%) in students who had attended more than half the workshops, by the end of the programme. The programme also showed several significant benefits on students' academic performance. Students who attended all the workshops on essay writing and examination taking, obtained higher essay and examination marks than students who did not attend these workshops.However, when we looked at the effects on academic performance of taking a deep approach and holding a more sophisticated conception of learning, the findings were not so clear cut. Depending on the measure used, there was conflicting evidence about whether examination performance or essay performance benefitted the most. The implications of these results are discussed with particular reference to the role of assessment, in enhancing the quality of student learning.  相似文献   

Where is higher education in Francophone West Africa heading?     

João Batista Araujo e Oliveira 《Prospects》1987,17(4):503-527

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Student satisfaction in higher education: a meta-analytic study     

Fernando de Oliveira Santini  Wagner Junior Ladeira  Claudio Hoffmann Sampaio  Gustavo da Silva Costa 《Journal of Marketing for HIGHER EDUCATION》2017,27(1):1-18

This paper discusses the results of a meta-analysis performed to identify key antecedent and consequent constructs of satisfaction in higher education. We offer an integrated model to achieve a better understanding of satisfaction in the context of higher education. To accomplish this objective, we identified 83 studies that were valid and relevant to the research objective of the current study, generating a total of 469 observations. We identified studies published from 1986 to 2016 and analyzed six antecedent dimensions (perceived value of educational services, resources provided to the student, service quality perception, marketing orientation, identity of the higher education institution, university environment) and one consequent dimension related to satisfaction. The 7 dimensions exhibited a total of 51 relationships. We believe that the originality of the findings clearly contributes to future academic research in higher education.  相似文献   

Studying abroad: developing a model for the decision process of international students     

Diana Branco Oliveira 《Journal of Higher Education Policy & Management》2016,38(2):126-139

Attracting international students is increasingly important for higher education institutions. In order to contribute to the understanding of how international students choose a university, we conducted a qualitative study in a public university in the north of Portugal. Results show that students seek an international experience mainly for personal, academic and professional development reasons, relying on personal contacts as information sources and support groups. Academic reputation and quality are the most important attraction factors. We develop a theoretical model of the studying abroad decision process, including the main motivations to leave the country of origin, the information sources and the decision factors.  相似文献   

The effects of an educational video game on mathematical engagement     

Mido Chang  Michael A. Evans  Sunha Kim  Anderson Norton  Kirby Deater-Deckard  Yavuz Samur 《Education and Information Technologies》2016,21(5):1283-1297

In an effort to maximizing success in mathematics, our research team implemented an educational video game in fifth grade mathematics classrooms in five schools in the Eastern US. The educational game was developed by our multi-disciplinary research team to achieve a hypothetical learning trajectory of mathematical thinking of 5th grade students. In this study, we examined overall engagement and three sub-domains of engagement as outcome variables after ten sessions of treatment with fifth grade students. The results showed that both male and female the video game group had slight increases in all engagement levels while students, particularly male, in the paper-and-pencil drill group displayed large decreases in all engagement levels. Implications of the study are 1) more fine-grained evidence of engagement in three sub-domains after implementing an educational video game, and 2) a consideration of gender differences in engagement levels in mathematics in the adoption of a video games.  相似文献