El patrimoni educatiu, un element d'una pedagogia cultural i ciutadana

El present article desenvolupa els eixos de pensament que s’estan elaborant des de diferents angles sobre el patrimoni educatiu. Una revisió sobre la importància de les aportacions de les investigacions a l’entorn del patrimoni educatiu permet assenyalar els punts d’inflexió dels museus pedagògics en l’actualitat. Entre aquests destaca la influència que els museus pedagògics, a través de les seves activitats de recerca, difusió i formació, exerceixen en la conformació d’una pedagogia cultural i ciutadana. Amb la irrupció d’una pedagogia d’encuny culturalista, els museus pedagògics recuperen els fonaments i formes de creació de discurs de la pedagogia cultural sorgida a l’inici del segle XX, tot introduint les aproximacions etnogràfiques en les arrels dels estudis i investigacions. D’altra banda, també ressalta el fet que els museus pedagògics resignifiquen la seva acció a partir de les pedagogies ètiques que atorguen un paper principal als projectes de ciutadania. Així, doncs, ambdós aspectes, cultura i ciutadania, es perfilen com els trets diferencials dels museus pedagògics actuals. A més, aquesta caracterització requereix encara d’una reflexió sobre el sentit i amplitud dels canvis introduïts en els projectes museístics.

The role of aromaticity in determining the molecular structure and reactivity of (endohedral metallo)fullerenes

The encapsulation of metal clusters in endohedral metallofullerenes (EMFs) takes place in cages that in most cases are far from being the most stable isomer in the corresponding hollow fullerenes. There exist several possible explanations for the choice of the hosting cages in EMFs, although the final reasons are actually not totally well understood. Moreover, the reactivity and regioselectivity of (endohedral metallo)fullerenes have in the past decade been shown to be generally dependent on a number of factors, such as the size of the fullerene cage, the type of cluster that is being encapsulated, and the number of electrons that are transferred formally from the cluster to the fullerene cage. Different rationalizations of the observed trends had been proposed, based on bond lengths, pyramidalization angles, shape and energies of (un)occupied orbitals, deformation energies of the cages, or separation distances between the pentagon rings. Recently, in our group we proposed that the quest for the maximum aromaticity (maximum aromaticity criterion) determines the most suitable hosting carbon cage for a given metallic cluster (i.e. EMF stabilization), including those cases where the IPR rule is not fulfilled. Moreover, we suggested that local aromaticity plays a determining role in the reactivity of EMFs, which can be used as a criterion for understanding and predicting the regioselectivity of different reactions such as Diels-Alder cycloadditions or Bingel-Hirsch reactions. This review highlights different aspects of the aromaticity of fullerenes and EMFs, starting from how this can be measured and ending by how it can be used to rationalize and predict their molecular structure and reactivity

Spottier Targets Are Less Attractive to Tabanid Flies: On the Tabanid-Repellency of Spotty Fur Patterns

During blood-sucking, female members of the family Tabanidae transmit pathogens of serious diseases and annoy their host animals so strongly that they cannot graze, thus the health of the hosts is drastically reduced. Consequently, a tabanid-resistant coat with appropriate brightness, colour and pattern is advantageous for the host. Spotty coats are widespread among mammals, especially in cattle (Bos primigenius). In field experiments we studied the influence of the size and number of spots on the attractiveness of test surfaces to tabanids that are attracted to linearly polarized light. We measured the reflection-polarization characteristics of living cattle, spotty cattle coats and the used test surfaces. We show here that the smaller and the more numerous the spots, the less attractive the target (host) is to tabanids. We demonstrate that the attractiveness of spotty patterns to tabanids is also reduced if the target exhibits spottiness only in the angle of polarization pattern, while being homogeneous grey with a constant high degree of polarization. Tabanid flies respond strongly to linearly polarized light, and we show that bright and dark parts of cattle coats reflect light with different degrees and angles of polarization that in combination with dark spots on a bright coat surface disrupt the attractiveness to tabanids. This could be one of the possible evolutionary benefits that explains why spotty coat patterns are so widespread in mammals, especially in ungulates, many species of which are tabanid hosts