Large dams degrade the integrity of a wide variety of ecosystems, yet direct downstream effects of dams have received the most attention from ecosystem managers and researchers. We investigated indirect upstream effects of dams resulting from decimation of migratory freshwater shrimp and fish populations in Puerto Rico, USA, in both high- and low-gradient streams. In high-gradient streams above...

In the fall of 1982 we were contacted by a local radio announcer for information about a phenomenon he referred to as “backmasking.” However, his question did not concern the well-studied phenomenon of visual persistence (see DiLollo, 1980; Sakitt, 1976); the announcer wanted to know what were the effects on a listener of messages that allegedly had been recorded backward into popular rock musi...

Rundschau 85(1): 65{70. Abstract Erosion is a complex process consisting of many components, like surface runoo, impact of raindrops, wind forces, soil, and rock mechanics, etc. Trying to integrate all these processes into a physical model seems to be hopeless. In order to understand the variety of natural shapes and patterns produced by erosion we present an integrated statistical approach. Ou...

The four asteroids visited by spacecraft, Gaspra, Ida, Mathilde, and Eros, have shapes and surface morphologies dominated by the effects of impact cratering. The presence of impactderived regolith has been inferred on S-class asteroids Gaspra, Ida, and Eros from photometry, morphological features, and subtle color variations related to optical maturation of surface materials. Grooves and ridges...

Lithological characteristics, mineral composition, physical properties of water and physical and mechanical properties, weathering zone distribution and other factors of bedrock weathering zone in coal-seam roof determine the strength of its watertight performance, while its performance has a direct impact on impermeable overlying loose surface water aquifers as well as the possible collapse in...

A low-clearance tunnel portal in the shallow-buried, joint-developed, broken, and loose surrounding rock slope deposit may cause safety issues during construction. In this study, Guanyin Mountain Tunnel of Chong-Ai expressway was taken as a case characteristics broken rocks, their low clearance, shallow buried bias were comprehensively studied. The three-dimensional numerical model section cons...

In constructing high-geo-stress soft rock tunnels, the major deformation disaster of surrounding has always been main problem faced during construction. The research on and loose zone characteristics large tunnels positive significance for safe rapid construction tunnels. Therefore, based Yuntunpu tunnel, this article first analyzes geological tunnel site area in response to deformation. Subseq...

European Journal of Information Systems (2010) 19, 379–381. doi:10.1057/ejis.2010.40 In this issue of the European Journal of Information Systems (EJIS), we have a Special Section on I.S. in Interorganizational Networks and four more Opinion papers. The papers in I.S. in Interorganizational Networks were edited by Diederik W. van Liere, Peter H.M. Vervest, Benn Konsynski and Chris Holland. Than...

Longitudinal connectivity is a fundamental characteristic of rivers that can be disrupted by natural and anthropogenic processes. Dams are significant disruptions to streams. Over 2,000,000 low-head dams (<7.6 m high) fragment United States rivers. Despite potential adverse impacts of these ubiquitous disturbances, the spatial impacts of low-head dams on geomorphology and ecology are largely un...