The wind–water erosion crisscross region, where the topography is complicated, most severe area of soil on Loess Plateau. wind and terrain both have an impact water process. In order to evaluate effects sand cover runoff loss characteristics, a series experiments was conducted in two contrasting treatments. One treatment bare loess slope serving as control, others were sand-covered slopes with ...

A new species of abertellid sand dollar, Abertella miskellyi n. sp., is described from the Miocene Camarones Formation of Patagonia, southern Argentina. The new taxon corroborates the existence of the genus in South America, given that Abertella is most common in the southeastern USA and the eastern coast of Central America. It is characterized by a unique basicoronal circle, in which the inter...

a r t i c l e i n f o Ripples and transverse dunes in areas of abundant sand supply increase in height and spacing as a function of time, grain size, and excess shear velocity. How and why each of these factors influence ripple and transverse dune size, however, is not precisely known. In this paper, the controls on the height and spacing of ripples and transverse dunes in areas of abundant san...

the study was carried out to investigate the effective soil and topographic features on distribution of plant types in sanib taftan watershed in sistan-and-balouchestan province, iran. initially, land units map was specified by combining three maps of slope, aspect and altitude. five types including artemisia santolina- hammada salicornica, artemisia sieberi- amygdalus lycioides, artemisia lehm...

Augmenting water availability using water-harvesting structures is of importance in arid and semi-arid regions (ASARs). This paper provides an overview examines challenges prospects the sand dam application dry riverbeds ASARs. The technology filters protects from contamination evaporation with low to no maintenance cost. Sand dams improve socio-economy community help cope drought climate chang...

in order to sustainable use of rangelands, it is necessary to recognize water, soil, and vegetation cover and analyze their relationships. physical and chemical properties of soil are effective in distribution of plant species in local area. to determine the effects of some soil properties on species distribution of eurotia ceratoides and stipa barbata in baghedar summer region of bafgh, three ...

a r t i c l e i n f o Geologists, physicists, and mathematicians have studied ripples and dunes for more than a century, but despite considerable effort, no general model has been proposed to explain perhaps the most fundamental property of their morphology: why are some bedforms straight, continuous, parallel, and uniform in planform geometry (i.e. two-dimensional) whereas others are irregular...

Cellular automata provide a fascinating class of dynamical systems capable of diverse complex behavior. These include simpliied models for many phenomenaseen in nature. Among other things, they provide insight into self-organized critical-ity, wherein dissipative systems naturally drive themselves to a critical state with important phenomena occurring over a wide range of length and time scales...

Organisms with external fertilization are often sperm limited, and in echinoids, larger eggs have a higher probability of fertilization than smaller eggs. This difference is thought to be a result of the more frequent sperm-egg collisions experienced by larger targets. Here we report how two components of egg target size, the egg cell and jelly coat, contributed to fertilization success in a se...

A soil nailing system is a proven effective and economic method used to stabilize earth slopes from the external (factors increasing shear stress) internal decreasing material strength) failure causes. The laboratory models with scales of 1:10 are study behavior nailed slope different building foundation parameters. consist Perspex strips as facing steel bars increase stability slope. sand beds...