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The main goal of this work is to study the influence on mechanical bone behaviour using different thread profiles shapes considered in titanium dental implants. The biomechanical behaviour of bone and thread implant profile play an important role on the study of stresses and strains at bone-implant interface. The success of dental surgeries depends on the mechanical stimulus (stress, strain, strain rate, strain energy, density…) between the bone and the implant. In this work, four different threads profiles shapes were considered (Model 1 - Plateau typeA, Model 2 - Plateau typeB, Model 3 - Triangular, Model 4 - Rectangular) and for each one two internal diameters equal to 4 and 6mm. The results about the chosen thread profile shape and the diameter give additional information about the transferred stresses between bone-implant to guarantee the stability of the implant and sustain loads during or after osseointegration.

Peach fruits were collected in the period between anthesis and harvest. The relationship between histological structure, free abscisic acid (ABA) and carbohydrate content was investigated in control seeds (class A) and in the seeds of fruit that were affected by fruit-drop and that were not yet abscised from the plant (class B). The results of the histological analysis showed that seeds from class A generally showed a normal embryogenesis, whereas we did not detect any embryo and endosperm in seeds of class B because they were undergoing degeneration. The ABA level reached a positive peak during the first 75 days after anthesis in seeds of class A, whereas the seeds of class B showed a negative peak in the same period. Carbohydrate content followed a similar trend to that of ABA. Results are discussed in relation to the development of the fruits.

The Bureau National de Metrologie, Laboratoire Primaire du Temps et des Frequences (BNM-LPTF) Time Section is in charge of generating and disseminating the French atomic time scale TA(F). The latter is obtained in deferred time (1 month) as a weighted average of individual atomic clock readings using an algorithm which aims to optimize the long-term stability of the resulting time scale. With the GPS time transfer capabilities and the new commercial caesium clocks, the quality of the timing data has changed dramatically. Consequently, the time-scale algorithm was not adapted to assign a weight to the new clocks in relation to their quality. So a new algorithm (TAC) has been built, with more sensitive statistical processing than the previous one. Tests have been carried out on real clock data covering the last few years; they have shown an improvement in the stability of the time scale. Since 1 January 1997 at 00:00:00 UT, the time scale TA(F) has been obtained by the algorithm TAC. Details of this new algorithm are presented.

Graphic tools for technical communication : analyzing how they are taught and learned Difficulties concerning the teaching and learning of three graphical tools (kinematic diagram, automated function diagram and technical drawing) are analysed through a psychological model of the situated use of technical graphics in design and communication settings. Graphic communication activities in technology education are examined in respect to the different types of relations among the elements of technical communication situations : participants, graphic code, referent and context. Pedagogical suggestions are made focusing on the conditions through which students may acquire a more instrumental and generative approach to technical graphics., À l'aide d’une modélisation psychologique des situations d’utilisation d’instruments de communication et de représentation techniques, on s’interroge sur les difficultés que posent l’enseignement et l’apprentissage de trois graphismes techniques : le schéma cinématique, le Grafcet et le dessin technique. Des situations de formation sont examinées en fonction des différentes interactions possibles dans les situations de communication de référence entre les sujets interlocuteurs, l’instrument sémiotique ainsi que le référent et la tâche concernés. Des propositions cherchant à favoriser un enseignement centré sur la fonctionnalité et la générativité de l’instrument pour l’élève sont formulées., Contribución al análisis de las situaciones de enseñanza/aprendizaje de instrumentos semióticos de comunicación técnica A la ayuda de una modelización sicológica de situacioñes de utilización de instrumentos de comunicación y de representación técnicas, nos preguntamos sobre las dificultades que provocan le enseñanza y el aprendizaje de tres grafismos técnicos : el esquema cinemático, el “Grafcet” y el dibujo técnico. Situaciones de formación son examinadas en función de diferentes interacciones posibles en las situaciones de comunicación de referencia entre los sujetos interlocutores, el instrumento semiótico así que el referente y la tarea que concierne. Diferentes proposiciones, buscando favorizar una enseñanza centrada sobre la funcionalidad y la generatividad del instrumento por el alumno son formuladas., Andreucci Colette, Froment Jean-Pierre, Verillon Pierre. Contribution à l'analyse des situations d'enseignement/apprentissage d'instruments sémiotiques de communication technique. In: Aster, recherches en didactique des sciences expérimentales, n°23, 1996. Enseignement de la technologie. pp. 181-211.

Untamed ecosystems and plots of wild nature increasingly constitute large parts of contemporary urban spaces. They are often the unbidden result of a long-standing lack of maintenance as well as of the uncontrolled flourishing of weeds produced by the pesticide absolute ban. But they are also something more. Many recently implemented urban open spaces deal with wild nature to solve some of the most urgent tasks of the contemporary cities: reclaiming areas fallen into disuse, designing sustainable infrastructures, revitalizing valuable public spaces, enhancing the ecological footprint of new developments, suggesting new practices and social ritual, reducing management costs, fighting climate change, and satisfy- ing the biophilic desire of nature of urban dwellers. Thus, some questions arise: why and how can urbanity and wildlife come together? Why and how can we design and manage untamed urban landscapes? Which kind of behaviours do they encourage? Which ethical and aesthetical categories do they entail? This paper aims to inquire the role of wilderness in the urban realm, in a critical perspective. On one side, we will explore the proactive value of untamed landscapes as a priceless resource to improve urban quality. On the other, we will wonder about the risks of a possible ideological status of wilderness, as a fashionable label to renew anti-urban positions.