The Maya “Protoclassic” from the Perspective of Recent Research at Nakum,Peten, Guatemala

Recently, the Maya site of Nakum has been the subject of intensive research by the Institute of Archaeology of the Jagiellonian University, Kraków, Poland. This work has significantly enriched our knowledge of the ancient Maya of northeastern Guatemala, especially during the so-called Terminal Preclassic or Protoclassic period (ca. 100 b.c.–a.d. 300), when many Maya centers suffered decline. The Protoclassic covers the transitional moment between two important periods of Maya chronology, the Preclassic and Classic, but so far, the typical ceramic components of this phase have been found in only a handful of Maya sites. Our research indicates that Nakum underwent important building programs and stable cultural growth during the discussed period. Here we discuss evidence of architectural and cultural activity at Nakum during the Terminal Preclassic within a wider geographic context. Our research highlights the role that Nakum played within Maya geopolitics in northeastern Guatemala and also contributes to the understanding of socio-cultural processes that the Maya civilization was undergoing during the as-yet poorly understood Protoclassic period.     

Experimental characterization of the constitutive materials composing an old masonry vaulted tunnel of the Paris subway system

A significant proportion of the Paris metro tunnels comprise a masonry vault built out of stone blocks and mortar joints, and sidewalls and slabs made of unreinforced concrete. In order to provide the necessary data for future structural evaluation, an extensive laboratory testing programme has been conducted to characterize the materials of the tunnel separately, i.e., mortar, stone, and concrete. The tests, carried out on specimens taken from cores extracted from a 1930s tunnel, enabled to determine the mechanical properties, including direct tensile, shear strength, and mode I fracture energy, as well as the properties of the stone-mortar interface. Results show that the masonry mortar joints could reach 10 cm in width, and that blocks of stone varied in composition and porosity, thus producing a wide range of mechanical properties. The concrete was composed of large-sized aggregates and showed low stiffness and strength. Based on these experimental results, ratios between mechanical characteristics are hereby proposed. Perspectives on the use of this experimental data in a finite element model are then discussed.     

Le Quartier: Étude Géographique Et Psycho-Sociologique

Les problèmes de la vie sociale en milieu urbain doivent être étudiés non dans un espace géographique au sens étroit, ni dans un espace social indépendent de l'espace géographique mais dans un espace socio-géographique qu'il importe de définir pour chaque agglomération. (P.-H. Chombart de Lauwe, Des hommes et des villes , p. 41)