Mathematical models for water quality problems in rivers and streams are now an efficient tool in water resources management. Their basic principle is the differential equation of pollution transport, which can be integrated both in analytical and numerical form. From this equation the broad category of “fickian” models has been developed. The numerical procedures available so far are the finit...

Arid zones have been affected during the quaternary by a large hydrological and climate variability. This change of processes has shaped the landscape leaving the signature of former paleodrainage and sedimentological features. Using the radar SAR images matched with the detailed topography, obtained from the SRTM (Shuttle Radar Topography Mission) data and ERS interferometry, it is possible to...

The Protocolised Management in Sepsis (ProMISe) trial (April 2 issue) completes a trio of studies that question the further application of early, goal-directed therapy (EGDT) as suggested by Rivers et al. In particular, these trials consistently show no survival benefit with regard to the mandated use of central venous oxygen saturation (ScvO2) monitoring. However, it remains questionable wheth...

1. Compared with rivers in more humid, forested ecoregions of eastern and midwestern U.S.A., rivers in semi-arid grassland of the U.S. Great Plains tend to be relatively shallow, more variable in discharge, and characterised by high suspended sediment loads. Although critical life stages of fish in prairie rivers probably depend at least partially on zooplanktonic food, data on community and di...

Water scarcity is one of the factors limiting plant growth and development. More than onethird of the global terrestrial ecosystems is located in arid and semi-arid regions. The mostimportant limiting factor for plant growth is water shortage. Drought could significantlychange the natural vegetation cover. Rainfall reduction in Iraq, Turkey and Syria hasreduced vegetation cover so that dust sto...

study of fishes on aquatic ecosystems in many respects, including ecology, behavior, biology, conservation and management of water resources, exploitation of resources and training are important. so in the autumn 2011, the population structure of barilius mesopotamicus was studied. in this order, 69 samples of the mentioned fish from seimareh (34 samples), changoleh (20 samples) and siahgave (1...

2,4,7,9-Tetramethyl-5-decyne-4,7-diol (TMDD) is a non-ionic surfactant which is preferentially used as defoamer in paints and printing ink and for the treatment of surfaces. Effluents of wastewater treatment plants (WWTPs) have been identified as the domination point sources for TMDD in rivers since the removal rate of the compound in the WWTPs is in general less than 70%. However, the dominati...

The Neotropical Ambrysus stali La Rivers species complex is reviewed and includes A. bifidus La Rivers & Nieser, A. scolius La Rivers, A. stali La Rivers, and A. tricuspis La Rivers. Ambrysus oblongulus Montandon is removed as a member of this complex. Features uniting these species are related to male genitalia and associated structures. Ambrysus maya n. sp. is the fifth species in the complex...