BACKGROUND The Drosophila eye is composed of about 800 ommatidia, each of which becomes dorsoventrally polarised in a process requiring signalling through the Notch, JAK/STAT and Wingless pathways. These three pathways are thought to act by setting up a gradient of a signalling molecule (or molecules) often referred to as the 'second signal'. Thus far, no candidate for a second signal has been ...

In this paper attempts have been done to create a mortar with relatively high uniaxial compressive strength (UCS), easy casting, high flexibility, instant hardening, low cost and easy availability. The main use of this material is to physically model the mechanical behavior of jointed rock-like blocks. The effect of four parameters such as joint roughness coefficient (JRC), bridge length (L), b...

The molecular basis of segmentation and regional growth during morphogenesis of Drosophila legs is poorly understood. We show that four-jointed is not only required for these processes, but also can direct ectopic growth and joint initiation when its normal pattern of expression is disturbed. These effects are non-autonomous, consistent with our demonstration of both transmembrane and secreted ...

In this paper an attempt is made to offer insights into local slope failure mechanisms from the perspective of hydrogeology. The hypothesis examined envisages that the hydraulic conductivity distribution in a weathered profile includes a relatively high hydraulic conductivity zone associated with the jointed rock mass near rockhead. There is evidence locally for such a condition. The groundwate...

The main rock mass classification systems make use of similar rock mass parameters. Due to lack of comprehensive estimation systems, determining the real specifications of jointed rocks faces some difficulties. A vast number of parameters with various degrees of impact are involved in such definitions. Combination impact of all the effective parameters is to be figured out in order to come up w...

Fluid flow in jointed rock mass with impermeable matrix is often controlled by joint properties, including aperture, orientation, spacing, persistence and etc. On the other hand, since the rock mass is made of heterogeneous and anisotropic natural materials, geometric properties of joints may have dispersed values. One of the most powerful methods for simulation of stochastic nature of geometri...

Uniaxial compressive and Brazilian tensile strengths (UCS and BTS) of rocks are considered important properties in the design of most the geotechnical projects that interact with rock such as slope stability and underground excavation. Measuring UCS and BTS using standard laboratory tests are time consuming, tedious and expensive. Moreover, it requires a large number of well-prepared rock cores...

The results form the application of the method of homogenization for the transport of solute in a porous medium with microscale pores and the rock matrix are applied to examine the dispersion characteristics of a solute in a porous rock matrix with parallel fractures including the retardation in the rock matrix and the decay effects. By using the solutions to a boundary value problem the effect...