A Five-Step Procedure for the Dimensioning of Viscous Dampers to Be Inserted in Building Structures

Viscous dampers have widely proved their effectiveness in mitigating the effects of the seismic action upon building structures. In view of the large impact that use of such dissipative devices is already having and would most likely have soon in earthquake engineering applications, this article presents a practical procedure for the seismic design of building structures equipped with viscous dampers, which aims at providing practical tools for an easy identification of the mechanical characteristics of the manufactured viscous dampers which allow to achieve target levels of performances. Selected numerical applications are developed with reference to simple, but yet relevant, cases.     

The phylogenetic relevance of the sacrum among macronarian sauropods: insights from a pelvis from the Upper Cretaceous of Patagonia,Argentina

Filippini, F.S., Otero, A. & Gasparini, Z., June 2016. The phylogenetic relevance of the sacrum among macronarian sauropods: insights from a pelvis from the Upper Cretaceous of Patagonia, Argentina. Alcheringa 41, xxx–xxx. ISSN 0311-5518.

Anatomical variation in the sacrum is useful for differentiating sauropod lineages. Morphological variation in the sacrum has been underestimated mainly because of its anatomical complexity and uncertain homologies with presacral and postsacral elements. We describe a titanosaurian sauropod pelvis (MLP 46-VIII-21-2) from Plottier (Neuquén Province, Argentina) collected in the 1940s from Coniacian–Santonian (Upper Cretaceous) strata. The degree of bone fusion in the specimen (fused vertebral centra forming a single rod, with neural arches fused to the corresponding centrum and to adjacent neural arches) indicates a late ontogenetic age. The presence of a space between the first vertebra and the anterior margin of the illium, together with a scar located on the anterior part of the preactabular process, suggest the possible presence of a sixth sacral vertebra (putative dorsosacral additional characters present in the ilium point towards affinities with Titanosauria. The completeness and good preservation of the specimen allowed us to track features along the sacral series and to compare characters with other sauropods. Within a phylogenetic context, and based on the pattern present in basal sauropodomorphs, the presence of three sacral elements attached to the rim of the acetabulum in eusauropods opens the possibility for considering such elements as primordial sacrals.

Florencia S. Filippini [florencia304@live.com.ar], División Paleontología de Vertebrados, Museo de La Plata, Paseo del Bosque s/n, La Plata, 1900, Bs. As., Argentina; Alejandro Otero [alexandros.otero@gmail.com]; Zulma Gasparini [zgaspari@fcnym.unlp.edu.ar] CONICET—División Paleontología de Vertebrados, Museo de La Plata, Paseo del Bosque s/n, La Plata, 1900, Bs. As., Argentina.     

A review of the Quaternary Tayassuidae (Mammalia,Artiodactyla) from the Tarija Valley,Bolivia

Five successive events can be widely recognized in the Tremadoc to early Arenig graptolite sequences of the world: 1, appearance of Dictyonema flabelliforme s.l. at the base; 2, appearance of Anisograptus; 3, appearance of Clonograptus and/or Adelograptus; 4, appearance of Temnograptus, Kiaerograptus, large Clonograptus and Tetragraptus; and 5, appearance of Tetragraptus approximatus at the base of the Arenig. The five events are used as a basis for distinguishing 5 successive graptolite assemblages and for correlating Tremadoc sequences. The most precisely and confidently correlated horizon is that of event 5, the appearance of T. approximatus; the next best is that based on event 4. Derivation of the biradiate Anisograptids, Clonograptus, and Adelograptus, from their presumed ancestor, Dictyonema flabelliforme, now appears to have passed through a stratigraphically, if not phyletically, intermediate stage represented by the triradiate Anisograptus, Triograptus and Bryograptus.