1. The rate of urine production in the terrestrial crabs Gecarcinus lateralis (Freminville) and Cardisoma guanhumi Latreille maintained on s.w.-moist sand was measured by inulin clearance. 2. The inulin U/B ratios in both species rose to about unity after 48 h, and remained at this level. It was concluded that neither species withdrew water from the primary urine. 3. The relatively high rate of...

in desert areas high temperature and low precipitation limit growth and development of plants. under this circumstances wind becomes the most important erosion and transportation factor in these areas. there are four great sand masses in the central part of dasht-e-kavir namely rig-e-jen, rig-e-sargardan (shotori or halvan), rig-e-kharturan, and rig-e- chah-e-jam. these great sandy masses show ...

An increase in intracellular Ca2+ concentration ([Ca2+]) and morphological were simultaneously observed by epifluorescence and differential interference contrast (DIC) microscopy during fertilization of the sand dollar, Clypeaster japonicus. [Ca2+], which was detected by a Ca2+ indicator, Fluo-3, initially increased just beneath the sperm-attached site on the egg surface 8.6 sec after attachmen...

We summarize information concerning Recent and Pleistocene-Holocene Uruguayan sand dollars (Mellitidae), as well as Miocene taxa (Monophorasteridae). Recent and Pleistocene-Holocene species (Encope emarginata, Mellita quinquiesperforata, and Leodia sexisperforata) are at their southernmost limits of distribution, with only E. emarginata recorded further south than Uruguay. Lower temperatures to...

Many larvae and other plankton have complex and variable morphologies of unknown functional significance. We experimentally and theoretically investigated the functional consequences of the complex morphologies of larval sand dollars, Dendraster excentricus (Eschscholtz), for hydrodynamic interactions between swimming and turbulent water motion. Vertical shearing flows (horizontal gradients of ...

This young man presented initially and repeatedly over a period of twenty years with symptoms of irritability, depressed and withdrawn mood, impulsivity, out-of-control behavior, and suicidal ideation and behavior. These symptoms occurred with disabling intensity at ages 3 year, 6 1/2 years, and 8 1/2 years, when he had not yet been adequately diagnosed and treated with appropriate psychopharma...

Sand dripping in 1 dimensional Sand Pile Model is rst studied. Patterns and signals appear. Their behaviors and interactions are explained and asymptotic approximations are made. The total collapsing time of a single stack of sand is linear in function of the number of grains.