Averages of ratios vs. ratios of averages: An empirical analysis of four levels of aggregation     

Vincent Larivière  Yves Gingras 《Journal of Informetrics》2011,5(3):392-399

In the recent debate on the use of averages of ratios (AoR) and ratios of averages (RoA) for the compilation of field-normalized citation rates, little evidence has been provided on the different results obtained by the two methods at various levels of aggregation. This paper provides such an empirical analysis at the level of individual researchers, departments, institutions and countries. Two datasets are used: 147,547 papers published between 2000 and 2008 and assigned to 14,379 Canadian university professors affiliated to 508 departments, and all papers indexed in the Web of Science for the same period (N = 8,221,926) assigned to all countries and institutions. Although there is a strong relationship between the two measures at each of these levels, a pairwise comparison of AoR and RoA shows that the differences between all the distributions are statistically significant and, thus, that the two methods are not equivalent and do not give the same results. Moreover, the difference between both measures is strongly influenced by the number of papers published as well as by their impact scores: the difference between AoR and RoA is greater for departments, institutions and countries with low RoA scores. Finally, our results show that RoA relative impact indicators do not add up to unity (as they should by definition) at the level of the reference dataset, whereas the AoR does have that property.  相似文献   

Analysis of gene expression at the single-cell level using microdroplet-based microfluidic technology     

Mary P  Dauphinot L  Bois N  Potier MC  Studer V  Tabeling P 《Biomicrofluidics》2011,5(2):24109

  相似文献   

Fostering parents-professional collaboration for facilitating the school inclusion of students with ASD: design of the “ToGather” web-based prototype     

Mazon  Cécile  Etchegoyhen  Kattalin  Saint-Supery  Isabeau  Amestoy  Anouck  Bouvard  Manuel  Consel  Charles  Sauzéon  Hélène 《Educational technology research and development : ETR & D》2022,70(1):231-262

Educational technology research and development - In recent years, many psycho-educational technologies were studied to address the school-related difficulties encountered by students with autism...  相似文献   

Differences in Brain Activation Between Novices and Experts in Science During a Task Involving a Common Misconception in Electricity     

Steve Masson  Patrice Potvin  Martin Riopel  Lorie‐Marlène Brault Foisy 《Mind, Brain, and Education》2014,8(1):44-55

Science education studies have revealed that students often have misconceptions about how nature works, but what happens to misconceptions after a conceptual change remains poorly understood. Are misconceptions rejected and replaced by scientific conceptions, or are they still present in students' minds, coexisting with newly acquired scientific conceptions? In this study, we use functional magnetic resonance imaging (fMRI) to compare brain activation between novices and experts in science when they evaluate the correctness of simple electric circuits. Results show that experts, more than novices, activate brain areas involved in inhibition when they evaluate electric circuits in which a bulb lights up, even though there is only one wire connecting it to the battery. These findings suggest that experts may still have a misconception encoded in the neural networks of their brains that must be inhibited in order to answer scientifically.  相似文献   

Training educational administrators in Central America     

Jean-François Bernède 《Prospects》1977,7(1):113-117

  相似文献   

A tapered channel microfluidic device for comprehensive cell adhesion analysis, using measurements of detachment kinetics and shear stress-dependent motion     

Rupprecht P  Golé L  Rieu JP  Vézy C  Ferrigno R  Mertani HC  Rivière C 《Biomicrofluidics》2012,6(1):14107-1410712

We have developed a method for studying cellular adhesion by using a custom-designed microfluidic device with parallel non-connected tapered channels. The design enables investigation of cellular responses to a large range of shear stress (ratio of 25) with a single input flow-rate. For each shear stress, a large number of cells are analyzed (500–1500 cells), providing statistically relevant data within a single experiment. Besides adhesion strength measurements, the microsystem presented in this paper enables in-depth analysis of cell detachment kinetics by real-time videomicroscopy. It offers the possibility to analyze adhesion-associated processes, such as migration or cell shape change, within the same experiment. To show the versatility of our device, we examined quantitatively cell adhesion by analyzing kinetics, adhesive strength and migration behaviour or cell shape modifications of the unicellular model cell organism Dictyostelium discoideum at 21 °C and of the human breast cancer cell line MDA-MB-231 at 37 °C. For both cell types, we found that the threshold stresses, which are necessary to detach the cells, follow lognormal distributions, and that the detachment process follows first order kinetics. In addition, for particular conditions’ cells are found to exhibit similar adhesion threshold stresses, but very different detachment kinetics, revealing the importance of dynamics analysis to fully describe cell adhesion. With its rapid implementation and potential for parallel sample processing, such microsystem offers a highly controllable platform for exploring cell adhesion characteristics in a large set of environmental conditions and cell types, and could have wide applications across cell biology, tissue engineering, and cell screening.  相似文献   

Δ-distance: A family of dissimilarity metrics between images represented by multi-level feature vectors     

Marta Rukoz  Maude Manouvrier  Geneviève Jomier 《Information Retrieval》2006,9(6):633-655

This article presents the Δ-distance, a family of distances between images recursively decomposed into segments and represented by multi-level feature vectors. Such a structure is a quad, a quin or a nona-tree resulting from a fixed and arbitrary image partition or from an image segmentation process. It handles positional information of image features (e.g. color, texture or shape). Δ-distance is the generalized form of dissimilarity measures between multi-level feature vectors. Using different weights on tree nodes and different distances between nodes, distances between trees or visual similarity between images can be computed based on the general definition of Δ. In this article, we present three Δ-based distance families: two families of distances between tree structures, called -distance( for Tree) and -distance ( for Segment), and a family of visual distances between images, called ( for Visual). The -distance visually compares two images using their tree representation and the other two distances compare the tree structures resulting from image segmentation. Moreover, we show how existing distances between multi-level feature vectors appear to be particular cases of the Δ-distance  相似文献   

Coherence in professional education: does it foster dedication and identification?     

Kåre Heggen  Lars Inge Terum 《Teaching in Higher Education》2013,18(6):656-669

This article examines the impact of professional education on students' dedication to and identification with a profession. The premise is that professional education is not only about knowledge acquisition and reasoning but also about attitudes and aspirations. In fostering dedication and identification, students' experiences of relevance seem to be important. The concept of coherence seen as an expression of relevance is introduced and measured by four kinds of interactions: Theory–practice interaction, teacher–student interaction, peer interaction and supervisor–student interaction. Analysis indicates that coherence, particularly as theory–practice interaction, peer interaction and supervisor–student interaction, has a significant impact on dedication to and identification with a profession. Longitudinal survey data – collected from students in colleges for teaching, nursing and social work – are analysed.  相似文献   

Whisper it softly,professors are really academic developers too     

Michèle Saint‐Jean 《International Journal for Academic Development》2013,18(2):181-183

  相似文献   

Spelling,Reading Abilities and Speech Perception in Deaf Children with a Cochlear Implant     

Marie Simon  Lauren A. Fromont  Marie-Thérèse Le Normand 《Scientific Studies of Reading》2013,17(6):494-508

ABSTRACT

This study aims to compare word spelling outcomes for French-speaking deaf children with a cochlear implant (CI) with hearing children who matched for age, level of education and gender. A picture written naming task controlling for word frequency, word length, and phoneme-to-grapheme predictability was designed to analyze spelling productions. A generalized linear mixed model on the percentage of correct spelling revealed an effect of participant’s reading abilities, but no effect of hearing status. Word frequency and word length, but not phoneme-to-grapheme predictability, contributed to explaining the spelling variance. Deaf children with a CI made significantly less phonologically plausible errors and more phonologically unacceptable errors when compared to their hearing peers. Age at implantation and speech perception scores were related to deaf children’s errors. A good word spelling level can be achieved by deaf children with a CI, who nonetheless use less efficiently the phoneme-to-grapheme strategy than do hearing children.  相似文献