Following fertilization of the egg of the sand dollar Echinarachnius parma, tritiated thymidine (H(3)TDR) was taken up independently by the male and female pronuclei beginning within about 15 to 20 minutes, and the labeled pronuclei fused at about 30 to 40 minutes. At cleavage 90 minutes later the labeled nuclear material was distributed to both daughter cells. Unfertilized eggs and sperm expos...

Avalanches of various sizes occur due to instability during sand dune dynamics. A physically viable equation to model sand dune dynamics is a first order nonlinear difference equation. To visualize the size distribution of avalanches, sand dune dynamics has been numerically simulated by changing the strength of nonlinearity parameter (λ) that shows different impacts on dune dynamics. An equatio...

BACKGROUND In Turkey, vector control programs are mainly based on indoor residual spraying with pyrethroids against mosquitoes. No special control program is available for sand flies. Most insecticide susceptibility tests were done for mosquitoes but not for sand flies. We therefore aimed to determine the insecticide susceptibility against two commonly used insecticides; deltamethrin and permet...

[1] Measurements of sand flux and water flow in the Mississippi River are presented for a portion of the system 35–50 km upstream from the head of its subaerial delta. These data are used to provide insight into how nonuniform flow conditions, present in the lower reaches of large alluvial rivers, affect the timing and magnitude of sand transport near the river outlet. Field surveys during both...

Substrate-borne vibration for locating mates, predators and prey is widespread in the animal kingdown. Antlion larvae dig funnel-shaped traps to catch ants and they are totally immersed in dry sand. We used a playback setup reproducing an ant walking on sand to clearly demonstrate that antlions use sand-borne vibrations to locate their prey. Half the tested animals moved towards the stimulus so...

A laboratory-based methodology to launch cylindrical sand slugs at high velocities is developed. The methodology generates well-characterised soil ejecta without the need for detonation of an explosive; this laboratory-based tool thereby allows for the experimental investigation of the soil-structure events. The experimental set-up comprises a launcher with a cylindrical cavity and a piston to ...

Within areas of the Chihuahuan Desert dominated by honey mesquite bushes (Prosopis glandulosa), soil erosion causes open eroded patches and the formation of large coppice dunes. The airflow patterns around the dunes and through the open areas are correlated with sand flux and erosion. This study uses wind velocity simulations from the Quick Urban and Industrial Complex (QUIC) model in combinati...

Phlebotomine sand flies transmit Leishmania, phlebo-viruses and Bartonella to humans. A prominent gap in our knowledge of sand fly biology remains the ecology of their immature stages. Sand flies, unlike mosquitoes do not breed in water and only small numbers of larvae have been recovered from diverse habitats that provide stable temperatures, high humidity and decaying organic matter. We descr...

In this paper, we summarize the recent advances on the electrification of wind-blown sand. Some of the outstanding questions, such as the interpretation of the electrification of wind-blown sand, measurements on and models of the features of the wind-blown sand E-fields, as well as their effect on the wind-blown sand flux and electromagnetic wave propagation, are reviewed. We end by highlightin...

The behavior of sand crushing will appear when the confining pressure is up to a certain value, which results in disappearing of the positive dilatancy of sand. Adopting a new hardening parameter with the crushing stress, an elastoplastic constitutive model considering sand crushing is proposed. Comparing the conventional triaxial compression test results with the model prediction, it shows tha...