1,721,077 research outputs found
Linguaggio, mente, mondo. Saggi di filosofia del linguaggio, filosofia della mente e metafisica
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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
Towards a general model of space weathering of S-complex asteroids and ordinary chondrites
No full textContext: The effect of the space weathering on the spectral properties of the S-complex asteroids has been widely discussed in recent times, and a systematic reddening due to the exposure to the various influxes has been found. The evolution of spectral properties is also affected by other processes, such as close encounters with planetary bodies.
Aims: In this paper we present our model of asteroidal space weathering, combining the previous analyses and using an increased dataset. We also provide a link with ordinary chondrite meteorites.
Methods: We revise also some age estimates in terms of dynamical and physical considerations.
Results: The present analysis qualitatively confirms the previous results, but a by far more refined and reliable slope-exposure relation is obtained, capable to include in a unique scenario the ordinary chondrite meteorites, NEOs, Mars Crossers and Main Belt asteroids. Moreover, we show that, on the basis of spectroscopic properties, Mars Crossers should be, on the average, significantly younger than Main Belt asteroids of the same size. Finally, we find that the solar ion flux is the most relevant source of the asteroidal space weathering.
Conclusions: . The properties of ordinary chondrite meteorites, NEOs, Mars Crossers and Main Belt asteroids can be included in a unique scenario. This has unveiled the relevant processes - some newly discovered - which play an important role in determining the evolution of the spectral properties of these bodies over time
Space weathering of asteroids: similarities and discrepancies between Main Belt asteroids and NEOs.
No full textBusiness game-based learning in management education
No full textBusiness Games are a specific typology of serious games which combine business simulations and games to support management and entrepreneurial training. This volume presents the theory and teaching methodology of business games. Active learning is the foundation of business game-based learning which places learners at the centre of the educational process: the interactive nature of games stimulates learning, and learning by doing through simulations prepares students to face and understand the ambiguities and uncertainties of the real working environment. With its balance of theoretical and practical content this book aims to meet the needs of lecturers and other education professionals interested in the use and development of business games. High school teachers and other education providers can learn how to correctly design a management course enriched by the use of a business game. The book also deals with the design and development of models that can be used in the creation of new software
A Unique Spectral Slope-Exposure Relation for Silicate-Rich Main Belt and Near-Earth Asteroids
No full textSpace environment acts on optical properties of silicate-rich asteroid surfaces: older asteroids are expected to be generally redder and darker than the younger ones. The space weathering depends mainly on the age, but it may depend also on the distance from the Sun, especially if the Sun-dependent effects (for example, ion bombardment) are assumed as dominant.
With the aid of a new method to compute the asteroids ages, we obtain a general and statistically significant relation between the spectral slope of the silicate-rich Main Belt and near Earth asteroids (NEAs) and the ``exposure" to space weathering, computed taking also into account the distance from the Sun.
The age estimates depend on various parameters and in particular, for near Earth asteroids, on the assumed rate of the Yarkovsky-driven orbital mobility. We show that the range of values of the Yarkovsky effect parameter allowing to obtain a unique slope-age or slope--exposure relation for Main Belt asteroids and NEAs is consistent with the recent experimental measurements
Discovery of Vesta Analogues among Near-Earth Objects
No full textIt is commonly agreed that most of near--Earth asteroids (NEAs) originate from the main asteroid belt, through a complex dynamical evolution involving the major dynamical resonances. However it is not easy to obtain reliable hints on the origin and following dynamical evolution pertaining to every individual near--Earth body. The evolution within the resonant regions, which is typically chaotic, and the possible close encounters with one or more of the inner planets usually destroy every significant memory of the original orbit. Only in the rare cases in which the spin vector is known, it may be used to evaluate the probability of having the body come from either of the main resonant channels (3:1 or nu6). Thus the most relevant and commonly available information on the possible origin comes out from the spectroscopic observations and taxonomic assessment. In this work we report the observations of four NEAs showing, for the first time, a striking spectroscopic similarity with the main belt (MB) asteroid 4 Vesta, which we can safely identify as their parent body
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