Cities of God? Medieval urban forms and their Christian Symbolism

Situated in the context of recent geographical engagements with 'landscape', this paper combines 'morphological' and 'iconographic' landscape interpretations to examine how urban forms were perceived in late medieval Europe. To date, morphological studies have mapped the medieval city either by classifying urban layouts according to particular types, or by analysing plan forms of particular towns and cities to reveal their spatial evolution. This paper outlines a third way, an 'iconographic' approach, which shows how urban forms in the Middle Ages conveyed Christian symbolism. Three such 'mappings' explore this thesis: the first uses textual and visual representations which show that the city was understood as a scaled-down world â?? a microcosm â?? linking city and cosmos in the medieval mind; the second 'mapping' develops this theme further and suggests that urban landscapes were inscribed with symbolic form through their layout on the ground; while the third looks at how Christian symbolism of urban forms was performed through the urban landscape in perennial religious processions. Each of these 'mappings' points to the symbolic, mystical significance urban form had in the Middle Ages, based on religious faith, and they thus offer a deepened appreciation of how urban landscapes were represented, constructed and experienced at the time.

Ovariole number - a predictor of differential reproductive success among worker subfamilies in queenless honeybee (Apis mellifera L.) colonies

A honeybee queen normally mates with 10-20 drones, and reproductive conflicts may arise among a colony's different worker patrilines, especially after a colony has lost its single queen and the workers commence egg laying. In this study, we employed microsatellite markers to study aspects of worker reproductive competition in two queenless Africanized honeybee colonies. First, we determined whether there was a bias among worker patrilines in their maternity of drones and, second, we asked whether this bias could be attributed to differences in the degree of ovary activation of workers. Third, we relate these behavioral and physiological factors to ontogenetic differences between workers with respect to ovariole number. Workers from each of three (colony A) and one (colony B) patrilineal genotypes represented less than 6% of the worker population, yet each produced at least 13% of the drones in a colony, and collectively they produced 73% of the drones. Workers representing these genotypes also had more developed follicles and a greater number of ovarioles per ovary. Across all workers, ovariole development and number were closely correlated. This suggests a strong effect of worker genotype on the development of the ovary already in the postembryonic stages and sets a precedent to adult fertility, so that

CO multipulse TAP studies of 2% Pt/CeO2 catalyst: Influence of catalyst pretreatment and temperature on the number of active sites observed

CO multipulse temporal analysis of products (TAP) experiments were used to characterize a ceria-supported platinum catalyst after various oxidative and reductive pretreatments using O-2, H2O, CO2, and H-2. Based on the amount of CO consumed, using the final CO-saturated catalyst composition as the common state point, the oxidatively pretreated catalyst could be described using a general scale. From a kinetic analysis of the CO multipulse responses, two kinetic regimes corresponding to two types of active sites could be identified. As the temperature was raised, the number of the most active sites did not change while the amount of the less active site increased. Comparison of the number of active sites determined from the TAP data reported herein with that determined by a previous steady-state isotope transient kinetic analysis experiment showed excellent agreement. This correlation indicates that the (very fast response) TAP experiments can provide information regarding the number and type of active sites that are relevant to a catalyst under real reaction conditions. (c) 2007 Elsevier Inc. All rights reserved.

Finding the magic number

Paul Wilson and Colin Cooper investigate methods used to extract the number of factors in a factor analysis