From inception to implementation: an Argentine case study of teachers enacting early years inquiry-based science     

Melina Furman  Mariana Luzuriaga  Inés Taylor  María Eugenia Podestá  Diana Jarvis 《Early Years: An International Journal of Research and Development》2019,39(4):408-425

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A compressed self-index using a Ziv–Lempel dictionary     

Luís M. S. Russo  Arlindo L. Oliveira 《Information Retrieval》2008,11(4):359-388

A compressed full-text self-index for a text T, of size u, is a data structure used to search for patterns P, of size m, in T, that requires reduced space, i.e. space that depends on the empirical entropy (H _k or H ₀) of T, and is, furthermore, able to reproduce any substring of T. In this paper we present a new compressed self-index able to locate the occurrences of P in O((m + occ)log u) time, where occ is the number of occurrences. The fundamental improvement over previous LZ78 based indexes is the reduction of the search time dependency on m from O(m ²) to O(m). To achieve this result we point out the main obstacle to linear time algorithms based on LZ78 data compression and expose and explore the nature of a recurrent structure in LZ-indexes, the suffix tree. We show that our method is very competitive in practice by comparing it against other state of the art compressed indexes.

Arlindo L. OliveiraEmail:

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Analysis and conservation of modern modeling materials found in Auguste Rodin's sculptures     

Juliette Langlois  Guylaine Mary  Hélène Bluzat  Agnès Cascio  Nathalie Balcar  Yannick Vandenberghe 《文物保护研究》2017,62(5):247-265

Prior to the exhibition Portrait-making, Rodin and his models (2009), the Rodin museum wanted to restore two busts of Hanako and Clemenceau. Interestingly, these two sculptures contain pieces of modern modeling materials (MMMs) invented at the end of the nineteenth century as an alternative to clay or waxes. The poor state of conservation of the two portraits made any handling and exhibition impossible. Accordingly, the purpose of this article is twofold: to contribute to technical art history and conservation. Elemental and chemical analyses were done on samples from 12 sculptures (SEM–EDX, FTIR, GC–MS, GC–FID, XRD, synchrotron-based µXRF, µXANES, and µFTIR) aimed at identifying the composition of MMMs used by Rodin on plaster sculptures and establishing hypotheses about the origins of their degradation. This thorough study of their composition and degradation was necessary to implement an appropriate restoration plan. The development of conservation protocols adapted to such materials is rarely documented. Different tests were performed on mock-ups (pH, solubility, adhesion, consolidation, and cleaning). In particular, a protocol based on laser cleaning was developed and successfully applied to remove superficial dust and crusts so that the sculptures regained their original aspect.  相似文献   

Learning environments at the margin: Case studies of disenfranchised youth doing science in an aquarium and an after-school program   总被引：1，自引：0，他引：1  

Jrène Rahm  Doris Ash 《Learning Environments Research》2008,11(1):49-62

In this article, we explore how two informal educational contexts—an aquarium and an after-school science program—enabled disenfranchised learners to adopt an identity as insiders to the world of science. We tell the stories of four youth, relating what doing science meant to them and how they positioned themselves in relation to science. We contribute to the extensive literature on the value of learning beyond the school walls, yet focus on ethnically and linguistically diverse youth from low-income backgrounds who have often been excluded from such settings. We suggest that such out-of-school settings are particularly important to youth who have few other opportunities to interact with and relate to science in positive ways.  相似文献   

Cytocompatible cellulose nanofibers from invasive plant species Agave americana L. and Ricinus communis L.: a renewable green source of highly crystalline nanocellulose     

Evdokimova  Olga L.  Alves  Carla S.  Krsmanović Whiffen  Radenka M.  Ortega  Zaida  Tomás  Helena  Rodrigues  João 《Journal of Zhejiang University. Science. B》2021,22(6):450-461

In this study, the fibers of invasive species Agave americana L. and Ricinus communis L. were successfully used for the first time as new sources to produce cytocompatible and highly crystalline cellulose nanofibers. Cellulose nanofibers were obtained by two methods, based on either alkaline or acid hydrolysis. The morphology, chemical composition, and crystallinity of the obtained materials were characterized by scanning electron microscopy(SEM) together with energy-dispersive X-ray spectroscopy(EDX), dynamic light scattering(DLS), X-ray diffraction(XRD), and Fourier transform infrared(FTIR)spectroscopy. The crystallinity indexes(CIs) of the cellulose nanofibers extracted from A. americana and R. communis were very high(94.1% and 92.7%, respectively). Biological studies evaluating the cytotoxic effects of the prepared cellulose nanofibers on human embryonic kidney 293 T(HEK293 T) cells were also performed. The nanofibers obtained using the two different extraction methods were all shown to be cytocompatible in the concentration range assayed(i.e., 0-500 μg/mL). Our results showed that the nanocellulose extracted from A. americana and R. communis fibers has high potential as a new renewable green source of highly crystalline cellulose-based cytocompatible nanomaterials for biomedical applications.  相似文献   

The development of analogical reading in Spanish     

Núria Sebastian-Gallés  Ana Parreño Vacchiano 《Reading and writing》1995,7(1):23-38

The use and development of analogical processes in learning to read in Spanish are presented. In the first experiment, the results show that children of 6 years old show analogical effects in reading pseudowords and that the magnitude of this effect is the same as with 10 years old children. However, it is found that children of 10 years old make many lexicalizations when reading pseudowords (about 50% of the items). In experiment 2 this finding is further analyzed. The results show that 9 years old children make more lexicalizations than adult control subjects do. It is suggested that the development of analogical procedures is a fast process (6 years old children already have done it), but that the precise control of lexical information over perceptual one is a later process.  相似文献   

Identifying Changes in a Student’s Mental Models and Stimulating Intrinsic Motivation for Learning During a Dialogue Regulated by the Teachback Technique: a Case Study     

Aliberas  Joan  Gutiérrez  Rufina  Izquierdo  Mercè 《Research in Science Education》2021,51(3):617-645

Research in Science Education - The aim of this paper is to show how an innovative technique can be used to introduce a method for uncovering intrinsic mechanisms that motivate changes in...  相似文献   

Uncertain Foundations     

Ferreirós  José 《Metascience》2004,13(1):79-82

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Représentations et fonctionnements cognitifs dans une recherche de panne d’un système d’allumage en mecanique-auto     

Annie Weill-Fassina  Carinne Filleur  Marie-Hélène Poulier 《European Journal of Psychology of Education - EJPE》1989,4(1):83-102

Fault finding is a puzzling task, at work and in technical and professional training. Our purpose is to contribute to an analysis of the required competencies and mainly to a characterisation of the evolution steps in knowledge and action organisation from novice to expert. Eight grown-up preparing a professional certificate in engine mecanics were observed and filmed while they were working out the diagnosis of an ignition trouble on a real equipment. The theory of functionning registers (deducted from Piaget’s theory) is considered as a relevant frame for our activity analysis. So, four competencies patterns has been outlined on the basis of errors extension, circuit functionning representations which were infered from schema interpretations, and trouble-shooting strategies denoted by control procedures. Some consequences about training are examined.  相似文献   

Constructing and understanding of place value in numerical notation     

Anne Sinclair  Anne Garin  Chantal Tièche-Christinat 《European Journal of Psychology of Education - EJPE》1992,7(3):191-207

The purpose of this study was to investigate how children aged five to nine gradually build up an understanding of the characteristics of place-value inherent in the written number system. The task consisted in presenting collections of chips, asking children to produce the corresponding two-digit numerals, and then questioning them in a structured clinical interview about the possible numerical meaning (in terms of correspondence to a number of chips) of each of the digits in the numeral. Results show that the idea that parts of the notation must correspond to mutually exclusive parts of the collection is but slowly built up, and that subsequently it is fleshed out by the use of knowledge concerning oral numeration_— written numeration correspondences. Intuitions concerning «groups of ten» arise later. A fair proportion of eight-year-olds and all nine-years-olds saw the two-digits as corresponding to, on the one hand, a number of units, and on the other, a number of groups of units.  相似文献