1,721,002 research outputs found
Teachers' interpretations of a proposal on "motion and force" in secondary school. Transformations of didactic intentions.
No full textThis qualitative research study, within the EU STTIS Project, investigates how teachers in different countries interpret the
description/instructions of a proposal for secondary schools called “Motion and Force” (M+F), which addresses: kinematics,
introduction to force and to force and motion, friction. A small sample of Italian (6), Spanish (3) and French (3) teachers have
been interviewed about a document (“M+F Instructions” MFI) that presents didactic intentions, rationale, activities, and
comments.
The study uncovered some gaps between teachers’ interpretations and the designers’ didactic intentions, together with
similarities/differences amongst the groups. The Italian teachers’ interest is focused on kinematics, that of the Spanish and
French teachers on the force area. Friction is globally overlooked. The path “From Real Phenomena to Ideal Cases/Models”,
one of (M+F)’s main features, is valued but only for the “observation of real phenomena” part; focus on observation of
regularities and modelling is lacking. Real-time experimentation is valued by the Italian teachers, more as a motivating than
as a cognitive tool, while the French teachers seem quite critical towards the use of real-time apparatuses. These differences
may well derive from specific curricula situations in EU countries and in the different degrees of familiarity with real-time
apparatuses.
These results indicate criteria and yield specific suggestions for improving the design/implementation of teacher training
programs and materials
Mechanical stability of Mt. Vesuvius Volcano: effects of asymmetries on the stress field
No full textThe effect of nonaxisymmetric elasticheterogeneities on the mechanical stability of a nearly axisymmetric volcanic structure, with particular reference to Mt. Vesuvius (Italy) is investigated. This is done solving numerical models using a finite element code in the framework of linear elasticity. The models include gravity,anisotropic depth-dependent regional stress, the edifice, the possible presence of a pressurized feeding system and of heterogeneities in the elastic behavior of country rocks. The criteria to assess instability are the development of tensile stresses and, in compression, the Navier–Coulomb criterion. The presence of asymmetric heterogeneous structures with lateral elastic contrast has been considered by solving three-dimensional (3D) models. To have computationally tractable models, axis-symmetric models were solved first, considering lateral symmetric heterogeneities of different shapes and sizes around the symmetry axis. This allowed us to assess the minimum size of smaller models (submodels) to be developed in 3D. The submodels were then solved including asymmetrical heterogeneities. In all the analyzed cases, the main characteristics of the instabilities/stabilities found with the 3D asymmetric models are very similar to those found by the analogous symmetric models. Moreover, the presence of sharp lateral elastic contrast at shallow depth appear to produce a greater instability on the flanks of the volcanic edifice
The influence of regional stress on mechanical stability of volcanic systems: Stromboli (Italy)
No full textTeachers' interpretations of a proposal on "motion and force" in secondary school. Transformations of didactic intentions.
No full textMeccanismi di inquinamento di acquiferi alluvionali determinati dalla ricaduta a terra dei vapori provenienti da cicli di lavorazione industriali. Il caso del fiume Chienti (Marche).
No full text
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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