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Vanessa Otero Joana V. Pinto Leslie Carlyle Márcia Vilarigues Marine Cotte 《文物保护研究》2017,62(3):123-149
The Winsor & NewtonTM (W&N) nineteenth century archive database includes digitised images of hand-written instructions and workshop notes for the manufacture of their artists’ materials. For the first time, all 183 production records for yellow lead chromate pigments were studied and evaluated. They revealed that W&N produced essentially three pigment types: lemon/pale based on mixed crystals of lead chromate and lead sulphate [Pb(Cr,S)O4]; middle on pure monoclinic lead chromate [PbCrO4]; and deep that contains the latter admixed with basic lead chromate [Pb2CrO5]; accounting for 53, 22, and 21% of the production, respectively. Production records for primrose (4%) were also included since the formulation results in mixed crystals with a high percentage of lead sulphate, which, according to the literature, leaves it more prone to degradation. Each pigment type is characterised by only one or two main synthetic pathways; process variations reveal a systematic and thorough search for a high-quality durable product. A comparison of the chemical composition of pigment reconstructions with early W&N oil paint tubes showed that their records entitled ‘pale’ and ‘lemon’ correlated with the pigment in their tube labelled chrome yellow and, ‘middle’ and ‘deep’ with the label chrome deep. Lemon and middle pigment formulations were made into oil paints to assess their relative photo-stability. The degradation process was followed by colorimetry and was studied by synchrotron radiation-based techniques. Based on the X-ray absorption spectroscopy data, the possibility for creating a stability index for chrome yellows is discussed. 相似文献
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Marine Cotte Emilie Checroun Wout De Nolf Yoko Taniguchi Laurence De Viguerie Manfred Burghammer 《文物保护研究》2017,62(1):2-23
The origin(s) and role(s) of metal soaps in paints are a worldwide concern today. These hybrid compounds, containing both fatty acid chains and metals associated with a carboxylate function, are increasingly identified in paints. As reviewed in the first part of this work, the presence of metal soaps in paints is differently interpreted in scientific publications: metal soaps are sometimes considered to play a positive role as anchor points, during paint drying processes; they can also be considered as responsible for many degradation processes (protrusions, efflorescences, darkening, etc.). Their origins are also interpreted in various ways. In some paintings (in particular from the twentieth century), they have sometimes introduced on purpose, as additives, to modify the physical properties of the painting materials. In older paintings, metal soaps are usually thought to result from an uncontrolled reaction of oil with lead-based pigments, in particular lead white, red lead, and lead tin yellow. In the second part of this work, the review of historical recipes of lead-based paint shows an important number of recipes based on controlled mixing of oil with lead driers. In the third part, the experimental reproduction of such traditional recipes using walnut oil and litharge (PbO) shows that lead soaps can be formed, both in about one hour at ～100°C, or in about one month at room temperature. It shows as well that after a few years, litharge is no longer detected in the paint medium, while different lead carbonates are. Finally, the micro-infrared spectroscopy and micro-X-ray diffraction re-analysis of protrusions from a nine-year model painting shows together with lead soaps, the presence of Pb5(CO3)3(OH)2O (‘synthetic plumbonacrite’), an unusual phase recently observed in a protrusion from a painting by Vincent Van Gogh. This work highlights (i) the multiple origins and roles of metal soaps in paints and (ii) the importance of combining the analysis of fragments from historical paintings with the analysis and reproduction of historical recipes. In particular, we show that the components detected today in historical paintings may severely differ from those originally used or prepared by the painter, complicating the assessment of the painter's intentions. More than the presence of metal soaps, the key questions to be tackled should be about their origins and (re)mobilization. 相似文献
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Marine Delaval Nicolas Michinov Olivier Le Bohec Benjamin Le Hénaff 《Interactive Learning Environments》2017,25(1):35-47
The aim of this study was to examine how social or temporal-self comparison feedback, delivered in real-time in a web-based training environment, could influence the academic performance of students in a statistics examination. First-year psychology students were given the opportunity to train for a statistics examination during a semester by doing online exercises in a web-based training environment. Once connected, students received in real-time either social comparison feedback (their score was compared to the mean score of all first-year students) or temporal-self comparison feedback (their score was compared, week by week, with their own previous score). The fact that students were free to connect to the web-based training environment heightened self-regulation differences such as academic procrastination, which was considered as a moderating variable in this study. Because academic performance was measured, the students’ background in mathematics and statistics was also controlled. Irrespective of the students’ background, the results reveal a positive influence of social comparison feedback on statistics exam performance, but only among students who did not delay doing exercises in the web-based training environment. By contrast, temporal-self comparison feedback did not have any effect on performance. Some recommendations for optimizing the efficacy of web-based training environments can be proposed, taking into account both social comparison feedback and academic procrastination. 相似文献
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Marine Rouchouse Aurelle De Romemont Ismail Moumouni Guy Faure 《The Journal of Agricultural Education and Extension》2015,21(4):325-342
Purpose: Approaches to build farmers' analytical capacities are said to trigger wide-ranging changes. This article reports on the communication process between participants and non-participants in one such approach, related to the technical and management skills learned by participants and the changes these participants subsequently made, and the outcomes in terms of non-participants' learning.
Design/Methodology/Approach: In this study, we analysed the following: (1) participants' learning and changes in social practices; (2) communication between participants and non-participants regarding technical and management skills and changes in social practices; (3) non-participants' learning and changes in social practices. The case study was a management advice to family farm project in three villages in Benin.
Findings: Most participants learned management skills, which led them to reassess their objectives and to reduce traditional social practices they now considered unproductive. Even in the case of frequent communication, non-participants found it difficult to learn management skills, which hindered their experiential learning. Non-participants consequently had difficulty understanding why participants changed their social practices such as reduction of their traditional gift giving, leading to limited well-argued discussion about these changes in practices between participants and non-participants.
Practical Implications: This study shows that, due to the limited learning process of non-participants communicating with participants, there is a need to design and test approaches to achieve capacity-building while including more participants at a similar cost, and to stimulate explicit discussion at village level about the changes in values and social practices that these approaches may trigger.
Originality/Value: The article analyses both participants and non-participants' experiential learning, and looks at the two sides of the interaction between the communication processes and non-participants' learning. 相似文献
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Marine Hascoët Pascal Pansu Thèrèse Bouffard Nadia Leroy 《European Journal of Psychology of Education - EJPE》2018,33(4):615-628
When children perceive a conditional support, they only feel loved and encouraged for their ability to meet others’ standards. This may lead them to develop high sensitivity to errors and anxiety and low perception of competence. In this study, we examined the relationship between the perceived conditional support from teacher and children’s self-perception of school competence. We tested the mediating effect of sensitivity to errors and test anxiety in the relationship between teacher conditional support and children’s perception of school competence. Participants were 524 elementary school students (aged 9–10 years). The results showed that the greater the extent to which the children perceived conditional support from their teacher, the lower their self-perceived scholastic competence. They also confirm that this relationship was mediated by sensitivity to errors and test anxiety. 相似文献
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Melanie A. Robinson Jean-François Soublière Marine Agogué Denis A. Grégoire Tuvana Rua Yves Plourde 《Decision Sciences Journal of Innovative Education》2023,21(3):167-176
Most graduate programs in management require students to carry out a substantive research project. However, few management students have a comfortable command of the statistical techniques needed to realize such quantitative projects. This can lead to student anxiety and stress, which challenges instructors to devise ways to build students’ self-efficacy with statistical analysis. Drawing on game-based learning principles, we developed an exercise to help students in a graduate-level research methods course practice these statistical techniques. Designed around a series of four gamified challenges, students perform basic statistical analyses (correlations, t-tests, and simple linear regression) to solve puzzles and unlock a reward hidden in a mysterious red envelope. We used the exercise on seven occasions (five times in the methods course and twice in a graduate program preparatory course). After launching it in fall 2021, we observed that students were engaged and enthusiastic about the exercise. To ascertain its effectiveness more systematically, we collected data in five subsequent sections using a pretest/posttest design (N = 84) which showed that perceptions of statistics self-efficacy increased following the exercise. We conclude by suggesting that our exercise can be tailored to other learning contexts such as management and statistics-centered courses. 相似文献
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Laurent Vigouroux Marine Devise Théo Cartier Clément Aubert Eric Berton 《Journal of sports sciences》2019,37(8):886-894
Pull-ups are often used by sport-climbers and other athletes to train their arm and back muscle capabilities. Sport-climbers use different types of holds to reinforce finger strength concomitantly. However, the effect of grip types on pull-up performance had not previously been investigated. A vertical force platform sensor measured the force exerted by climbers when performing pull-ups under six different grip conditions (gym-bar, large climbing hold, and four small climbing holds: 22mm, 18mm, 14mm, and 10mm). The electromyography of finger flexors and extensor muscles were recorded simultaneously. The maximal arm power and summed mechanical work were computed. The results revealed that the number of pull-ups, maximal power, and summed mechanical work decreased significantly with the size of the climbing hold used, even if no differences were found between a large climbing hold and a gym-bar. Electromyography of the forearm muscles revealed that the use of a climbing hold generated finger flexor fatigue and that the level of cocontraction was impacted by the different segment coordination strategies generated during the pull-ups. These findings are likely to be useful for quantifying training loads more accurately and designing training exercises and programs. 相似文献
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J. Roger Guard Ralph F. Brueggemann William K. Fant John J. Hutton John R. Kues Stephen A. Marine Gregory W. Rouan Leslie C. Schick 《Journal of the Medical Library Association》2004,92(2):171-178
The University of Cincinnati (UC) has been active in the National Library of Medicine''s Integrated Advanced Information Management Systems (IAIMS) program since IAIMS'' inception in 1984. UC received IAIMS planning and modeling grants in the 1980s, spent the 1990s practicing its own form of “iaims” and refining its vision, and, in May 2003, received an IAIMS operations grant in the first round of awards under “the next generation” program. This paper discusses the history of IAIMS at UC and describes the goals, methods, and strategies of the current IAIMS program. The goals of UC''s IAIMS program are to: improve teaching effectiveness by improving the assessment of health professional students and residents in laboratory and clinical teaching and learning environments; improve the ability of researchers, educators, and students to acquire and apply the knowledge required to be more productive in genomic research and education; and increase the productivity of researchers and administrators in the pre-award, post-award, and compliance phases of the research lifecycle. 相似文献
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James C. Hearn Carolyn P. Griswold Ginger M. Marine 《Research in higher education》1996,37(3):141-178
This paper reports on an investigation of differences and similarities across the 50 states in approaches to the pricing and discounting, via student aid, of undergraduate education. To examine national patterns in tuition and aid policies, the analysis used recent state-by-state data and multivariate statistical methods. The results suggest that region, social and economic resources, and postsecondary governance arrangements each have distinctive connections to the nature of states' tuition and aid policies. Of particular interest are the results relating to high-tuition/high-aid policies at the state level, an approach termed by proponents therationalization of tuition and aid policy. Multiple regression analysis revealed rationalization to be primarily a regionally driven phenomenon concentrated in the Northeast and Midwest. Rationalization showed weaker, but still significant, connections to the states' population, personal income levels, extent of reliance on private postsecondary institutions, and governance arrangements. Implications of these findings for theory and policy are discussed. 相似文献