Soil heterogeneity is an important driver of divergent natural selection in plants. Neotropical forests have the highest tree diversity on earth, and frequently, soil specialist congeners are distributed parapatrically. While the role of edaphic heterogeneity in the origin and maintenance of tropical tree diversity is unknown, it has been posited that natural selection across the patchwork of s...

Consider a reflecting diffusion in a domain in R that acquires drift in proportion to the amount of local time spent on the boundary of the domain. We show that the stationary distribution for the joint law of the position of the reflecting process and the value of the drift vector has a product form. Moreover, the first component is the symmetrizing measure on the domain for the reflecting dif...

We introduce a notion of viscosity solutions for a nonlinear degenerate diffusion equation with a drift potential. We show that our notion of solutions coincide with the weak solutions defined via integration by parts. As an application of the viscosity solutions theory, we show that the free boundary uniformly converges to the equilibrium as t grows. In the case of a convex potential, an expon...

The current concept for high-level radioactive waste disposal at Yucca Mountain is for the waste to be placed in underground tunnels (or drifts) in the middle of a thick unsaturated zone. Flow modeling and field testing have shown that not all flow encountering a drift will seep into the drift. The underlying reason for the diversion of unsaturated flow around a drift is that capillary forces i...

sensitivity of an electromagnetic type metal detector is directly related to stability, the higher the required sensitivity, the more frequently the rebalancing controls will have to be adjusted. thus, for maximum sensitivity in the head ,the use of automatic drift compensation network is necessary in order to cancel out the signal resulting from a slow drift in the coil system due to the tempe...

Most studies of active aeolian processes on Mars have focused on dust [1], i.e., particles -1 [tm in diameter that are transported in suspension by wind. The presence of sand dunes on Mars [2-8] indicates that larger grains ( >60 _tm, transported primarily in saltation) are also present. Although indirect evidence suggests that some dunes may be active [9], definitive evidence is lacking. Nonet...

Groundwater, being a vital resource, needs to be developed with proper understanding about its occurrence in time and space. Unscientific sand mining is a dominant environmental issue in this humid tropical river basin namely Bharathapuzha river basin geographically on central part of Kerala state, southwest part of India. The sandy layers along the river course declines its water holding capac...

Leishmaniasis is a vector-borne disease transmitted by bites of phlebotomine sand flies. During Leishmania transmission, sand fly saliva is co-inoculated with parasites into the skin of the mammalian host. Sand fly saliva consists of roughly thirty different salivary proteins, many with known roles linked to blood feeding facilitation. Apart from the anti-hemostatic capacity of saliva, several ...

[1] In this work we combine existing ideas on gravel and sand entrainment into a simulation model for flows that flush sand from the surface and subsurface of a gravel riverbed. A flume experiment is conducted to provide a test of the flushing model. The primary advance represented in this paper is incorporation of a two-fraction entrainment approach into a routing model to account for the effe...

A study was carried out to investigate correlation between presence of specific microalgal species and Leptoconops biting midge larvae in its breeding habitats. Sand samples containing microalgae were collected from the beach where the midges were most commonly biting and from sand beaches which are potential as breeding habitats of Leptoconops. The survey covered sand beaches from 12 seperate ...