5,995 research outputs found
Homophily, Cultural Drift and the Co-Evolution of Cultural Groups
In studies of cultural differentiation, the joint mechanisms of homophily and
influence have been able to explain how distinct cultural groups can form.
While these mechanisms normally lead to cultural convergence, increased levels
of heterogeneity can allow them to produce global diversity. However, this
emergent cultural diversity has proven to be unstable in the face of "cultural
drift"- small errors or innovations that allow cultures to change from within.
We develop a model of cultural differentiation that combines the traditional
mechanisms of homophily and influence with a third mechanism of 2network
homophily", in which network structure co-evolves with cultural interaction. We
show that if social ties are allowed to change with cultural influence, a
complex relationship between heterogeneity and cultural diversity is revealed,
in which increased heterogeneity can reduce cultural group formation while
simultaneously increasing social connectedness. Our results show that in
certain regions of the parameter space these co-evolutionary dynamics can lead
to patterns of cultural diversity that are stable in the presence of cultural
drift.Comment: (8 pages, 8 figures
Didactic strategies for comprehension and learning of structural concepts
p. 926-937In previous papers we have established the convenience of formulating educational
strategies at the university level for both disciplines: Civil Engineering and Architecture,
which involves academic topics of mutual interest by means of shared practices. As a
particular matter of this approach, the application of physical experimental models is
considered of special usefulness, in order to understand in better ways the performance of materials and structural systems.
Several strategies of selection and development of such physical models will be discussed in this work, considering as a first step, the establishment of its correspondence with the different levels of structural complexity studied in curriculum plan: statics, strength of materials and structural design, among others.
This task constitutes a part of the work program of the Laboratory of Structural Models,
which is an academic project that develops and applies different didactic prototypes to
structure courses in the Universidad Autónoma Metropolitana, campus Azcapotzalco, in
Mexico City, project we have already presented in recent forums.
Two different modes of application are implemented in classroom sessions and in
structures workshop: the devices for functional demonstration of typical cases of structural work as well as the experimentation with student's own designs of destructible models where certain typologies are tested up to its failure limit.
The first one allows teachers to explain adequately the theoretical principles and formulas
(that usually are expressed on the blackboard) by means of didactic models identified in
accordance to specific cases of the curriculum on variable level of complexity. This kind of practice allows the students of architecture and civil engineering to realize in better ways the possibilities of use and application of the different structural typologies. Such
experimental models are part of more than fifty devices of the Laboratory's catalog.
In the same sense, the possibility of observation of structural work of their own
architectural designs, allows future professionals to achieve a better conception of the
structural solutions that affect positively their designs. Based on specific predefined guides, the students develop their own architectural-structural projects and subject them to diverse loads, observing their behavior under the influence of variable stresses leading up the experiment to its last resistance.
From both experiences a significant learning is obtained for the student's formation and
training, who will be capable in his future professional work to use better tools of
comprehension of the structural concepts applied to architecture as well as of increasing his conscience of the benefits and convenience of multidisciplinary work.Moreno, C.; Abad, A.; Gerdingh, JG.; Garcia M., C.; Gonzalez C., O. (2010). Didactic strategies for comprehension and learning of structural concepts. Editorial Universitat Politècnica de València. http://hdl.handle.net/10251/695
About the linearity of the color-magnitude relation of early-type galaxies in the Virgo cluster
We revisit the color-magnitude relation (CMR) of the Virgo cluster early-type
galaxies in order to explore its alleged non-linearity. To this aim, we
reanalyze the relation already published from data obtained within the ACS
Virgo Cluster Survey of the Hubble Space Telescope, and perform our own
photometry and analysis of the images of the 100 early-type galaxies observed
as part of this survey. In addition, we compare our results with those reported
in the literature from data of the Sloan Digital Sky Survey. We have found that
when the brightest galaxies and untypical systems are excluded from the sample,
a linear relation arises in agreement with what is observed in other groups and
clusters. The central regions of the brightest galaxies also follow this
relation. In addition, we notice that Virgo contains at least four compact
elliptical galaxies besides the well known object VCC 1297 (NGC 4486B). Their
locations in the -luminosity diagram define a different trend to that
followed by normal early-type dwarf galaxies, setting an upper limit in
effective surface brightness and a lower limit in effective radius for their
luminosities. Based on the distribution of different galaxy sub-samples in the
color-magnitude and -luminosity diagrams we draw some conclusions on
their formation and the history of their evolution.Comment: 21 pages, 4 figures, 2 tables. Accepted for publication in Ap
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