ABSTRACT: It may be said that the shape of sand deposition is normally cone and sand grains are oriented a certain angle of deposition repose is made. This angle is such that no stability occurs. Thus the angle of repose is somewhat correlated to the sand internal friction angle. This paper presents the results of a series of laboratory experiments performed three types of sand. For this purpos...

Wind-blown sand movement often occurs in a very complicated desert environment where sand dunes and ripples are the basic forms. However, most current studies on the theoretic and numerical models of wind-blown sand movement only consider ideal conditions such as steady wind velocity, flat sand surface, etc. In fact, the windward slope gradient plays a great role in the lift-off and sand partic...

Calligonum mongolicum is a successful pioneer shrub to combat desertification, which is widely used for vegetation restoration in the desert regions of northwest China. In order to reveal the limitations to natural regeneration of C. mongolicum by asexual and sexual reproduction, following the process of sand dune stabilization, we assessed clonal shoots, seedling emergence, soil seed bank dens...

Solutions to Monge-Kantorovich equations, expressing optimality condition in mass transportation problem with cost equal to distance, are stationary points of a critical-slope model for sand surface evolution. Using a dual variational formulation of sand model, we compute both the optimal transport density and Kantorovich potential as t → ∞ limit of evolving sand flux and sand surface, respecti...

Most of the Tylenchulus semipenetrans larvae applied on the surface of four soils in pots 14.5-cm deep moved no further downward than 6.5 crn, and remained in the upper half of the pot. The percentage of second-stage larvae that developed into adult females on 'Homosassa' sweet orange in the soils were: sandy loam, 6.8% in the same soil with inoculation holes, 8.6%; loamy sand, 5.4%; coarse san...

BACKGROUND Leishmaniasis remains a global health problem because of the substantial holes that remain in our understanding of sand fly ecology and the failure of traditional vector control methods. The specific larval food source is unknown for all but a few sand fly species, and this is particularly true for the vectors of Leishmania parasites. We provide methods and materials that could be us...

Sand fields develop different patterns, such as sandbars, sand ridges, sand ripples, sand dunes, and river dunes. These vary in shape from crescent to ridge-like patterns. They are formed in areas such as deserts, lakes and seashores, where winds or fluid flows are strong and tend to blow from one direction or oscillate. There is a great deal of order in these patterns: perhaps a simple model c...

The western sand darter Ammocrypta clara, and eastern sand darter Ammocrypta pellucida, are sand-dwelling fishes of conservation concern. Past research has emphasized the importance of studying individual populations of conservation concern, while recent research has revealed the importance of incorporating landscape scale processes that structure habitat mosaics and local populations. We exami...

ENETIC analysis implying that mutable alleles at the gene locus V account Gfor flower color variegation in a Nicotiana culture has been presented by SMITH and SAND (1957). These plants also contain stable genes for flower color and have been found useful for the study of interaction between environmental factors and genetic systems of varying stability (SAND 1957, 1962). Other work with this ma...