The Lehmann discontinuity at 220-km depth is an important global feature which occurs under both oceans and continents. It is a barrier to penetration by young lithosphere and marks the base of seismicity in regions of continent-continent collision. The strong lateral variation in upper mantle velocities occurs mainly above this depth. Continental roots extend no deeper than about 150-200 km. T...

This paper is organized as follows. In Section 2, we introduce some basic concepts. In Section 3, we explain two strategies for symmetry exploitation during search. In Section 4, we present the problem of B I B D generation. In Section 5, we formulate the B I B D generation as a CSP and give empirical results. In Section 6, we revise previous approaches to this topic. Section 7 contains conclus...

BACKGROUND Dearterialization should reduce arterial overflow to haemorrhoids. The purpose of this study was to assess the topography of haemorrhoidal arteries. METHODS Fifty patients with haemorrhoidal disease were studied. Using endorectal ultrasonography, six sectors were identified within the lower rectal circumference. Starting from the highest level (6 cm above the anorectal junction), t...

abstract methods of tillage and organic matter affect root growth and distribution and therefore nutrient uptake by plant and its growth. this study was performed consecutive two years. tillage treatments included disk harrowing + two disk harrowings as reduced tillage (15 cm plowing depth) and moldboard plowing + two disk harrowings as conventional tillage system (30 cm plowing depth). also, t...

Recent stability studies using constitutive relations of the type found by Dieterich, Ruina. and others to describe frictional slip of rocks in the laboratory have provided a new explanation of the depth cutoff of shallow crustal earthquakes. The class of friction laws discussed has the property that the sliding stress depends on normal stress. temperature, slip rate, and slip history. For slid...