Thomas F. X. Noble, images, iconoclasm, and the carolingians, (The Middle Ages series), University of Pennsylvania Press, Philadelphia, 2009; 488 p., ISBN 978-0-8122-4141-9

Fil: Peretó Rivas, Rubén.

Niall W. Slater, Spectator Politics. Metatheatre and Performance in Aristophanes , Philadelphia, University of Pennsylvania Press, 2002, x + 362 pp.

Fil: Fernández, Claudia Nélida. Universidad Nacional de La Plata. Facultad de Humanidades y Ciencias de la Educación; Argentina.

Hunefeldt, Christine: Liberalism in the Bedroom: Quarrelling Spouses in Nineteenth -Century Lima; The Pennsylvania State University Press, University Park, Pennsylvania, 2000. XVII + 388 p.

Fil: Mallo, Josefina. Universidad Nacional de La Plata. Facultad de Humanidades y Ciencias de la Educación; Argentina.

Niall W. Slater, Spectator Politics. Metatheatre and Performance in Aristophanes , Philadelphia, University of Pennsylvania Press, 2002, x + 362 pp.

Fil: Fernández, Claudia Nélida. Universidad Nacional de La Plata. Facultad de Humanidades y Ciencias de la Educación; Argentina.

Hunefeldt, Christine: Liberalism in the Bedroom: Quarrelling Spouses in Nineteenth -Century Lima; The Pennsylvania State University Press, University Park, Pennsylvania, 2000. XVII + 388 p.

Fil: Mallo, Josefina. Universidad Nacional de La Plata. Facultad de Humanidades y Ciencias de la Educación; Argentina.

Hunefeldt, Christine: Liberalism in the Bedroom: Quarrelling Spouses in Nineteenth -Century Lima; The Pennsylvania State University Press, University Park, Pennsylvania, 2000. XVII + 388 p.

Fil: Mallo, Josefina. Universidad Nacional de La Plata. Facultad de Humanidades y Ciencias de la Educación; Argentina.

Transverse drainages of the Susquehanna River basin, Pennsylvania, USA

While large-scale transverse drainages (TDs) such as those of the Susquehanna River above Harrisburg, PA, have been recognized since the 19th century, there have been no systematic surveys done of TDs since that of Ver Steeg's in 1930. Here, the results are presented of a topographic and statistical analysis of TDs in the Susquehanna River basin using Google Earth and associated overlays. 653 TDs were identified in the study area, 95% of which contain streams with discharges of less than 10 m3/s. TD depths ranged from a 23 m deep water gap near Blain, PA, to the 539 m deep gorge of the Juniata River through Jacks Mountain. Although TD depth tended to increase with stream size, many small streams were located in deep gaps, and eight streams with discharges of 10 m3/s or less were found in gorges whose depths matched or exceeded the deepest TD of the Susquehanna, the largest stream in the basin. Streams of less than 10 m3/s made up the majority of TDs regardless of the rock type capping the breached structure. Overall, TDs through sandstone-capped ridges were deeper than those topped by shales, and TDs in both sandstones and shales displayed a lognormal distribution of depths, which may be indicative of a preferred value. Stream flow direction was primarily perpendicular to local structural strike, with 47% of streams flowing NW and 53% flowing SE. 19% of the TDs were found to be in alignment with at least one other TD, with aligned segment lengths ranging from .5 to 14.8 km. The majority of TDs were in rocks of Paleozoic age. The techniques described here allow the frequency and distribution of TDs to be quantified so that they can be integrated into models of basin evolution.

High speed railroad bridges. Conception, bases of design, typological possibilities and construction methods

Diseño conceptual de puentes de alta velocidad ferroviarios. Railroad bridges, in general, and those for high speed railways, in particular, demand very special conditions. The traffic loads are much higher than for road bridges. Loads due to braking and acceleration determine, due to their magnitude, the structural layout. Because of the speed of the vehicles there are specific dynamic effects which need to be considered. In order to ensure passenger comfort, compatible with speeds of up to 350 km/h, it is necessary to meet very demanding conditions with respect to stiffness, displacements and dynamic behavior. In this paper these conditions are briefly described and different typological possibilities to satisfy them are presented as well as the main construction methods applicable to this kind of bridges.

Effects of traffic loads on reinforced concrete railroad culverts

In the context of the present conference paper culverts are defined as an opening or conduit passing through an embankment usually for the purpose of conveying water or providing safe pedestrian and animal crossings under rail infrastructure. The clear opening of culverts may reach values of up to 12m however, values around 3m are encountered much more frequently. Depending on the topography, the number of culverts is about 10 times that of bridges. In spite of this, their dynamic behavior has received far less attention than that of bridges. The fundamental frequency of culverts is considerably higher than that of bridges even in the case of short span bridges. As the operational speed of modern high-speed passenger rail systems rises, higher frequencies are excited and thus more energy is encountered in frequency bands where the fundamental frequency of box culverts is located. Many research efforts have been spent on the subject of ballast instability due to bridge resonance, since it was first observed when high-speed trains were introduced to the Paris/Lyon rail line. To prevent this phenomenon from occurring, design codes establish a limit value for the vertical deck acceleration. Obviously one needs some sort of numerical model in order to estimate this acceleration level and at that point things get quite complicated. Not only acceleration but also displacement values are of interest e.g. to estimate the impact factor. According to design manuals the structural design should consider the depth of cover, trench width and condition, bedding type, backfill material, and compaction. The same applies to the numerical model however, the question is: What type of model is appropriate for this job? A 3D model including the embankment and an important part of the soil underneath the culvert is computationally very expensive and hard to justify taking into account the associated costs. Consequently, there is a clear need for simplified models and design rules in order to achieve reasonable costs. This paper will describe the results obtained from a 2D finite element model which has been calibrated by means of a 3D model and experimental data obtained at culverts that belong to the high-speed railway line that links the two towns of Segovia and Valladolid in Spain

Contributions from the Botanical Laboratory of the University of Pennsylvania.

1, 1892-1897

Contributions from the Botanical Laboratory of the University of Pennsylvania.

5, 1919-1920