Historically, rivers have served as sources of drinking water, fisheries resources, transportation routes, irrigation supplies, and waste removal systems. Human civilization has had many major effects on rivers, dating back more than 5000 years when Egyptians built dams on the Nile to supply water for crops and human consumption. Today, management of large rivers requires a balance between huma...

1. We used field surveys to compare the density and mesohabitat-scale distribution of the native coastrange sculpin (Cottus aleuticus) and the prickly sculpin (C. asper) in coastal rivers in north-western California, U.S.A., with and without an introduced piscivorous fish, the Sacramento pikeminnow, Ptychocheilus grandis. We also measured mortality of tethered prickly sculpin in a field experim...

the rotor of enegelberg whitener was equipped with a screw conveyor to reduce broken rice percentage. according to preliminary experiments this modification could reduce broken rice percentage about 2.5%. further experiment was performed to determine the effect of rotor speeds and blade positions on white rice quality. to do this, five rotor speeds, consisting 500, 600, 700, 800 and 900 r.p.m a...

Ship locks on mountain rivers usually experience difficulties owing to harsh flow conditions such as strong oblique and backflow, which significantly affect navigation safety efficiency. To improve conditions, a structural measure involving pile-foundation permeable dislocation-type diversion vanes, new type of structure, is proposed by analyzing the features working mechanisms existing structu...

the ph.d. entrance examinations of islamic azad university in iran are administered annually to select the best applicants for ph.d. programs. in consideration of the important decisions, which are made on the basis of the results of these examinations, the present study was conducted to provide a qualitative evaluation of field-specific language subtests (flss) of four entrance examinations ad...