In the Next Linear Collider design [1], the positron capture system includes a positron production target, followed by a short solenoid with a strong magnetic field (flux concentrator), a 250 MeV linac with solenoidal focusing, a 1.73 GeV linac with quadrupole focusing and an energy compressor system before injection into the positron pre-damping ring (see Fig. 1 for initial part of collector)....

The Levant vole, Microtus guentheri, is a pest of most of the field crops in Israel. It lives in gallery systems, the openings of which are clearly visible, and is active above ground mainly at night. Its activity was assessed by plugging the burrow openings (holes) and, after three nights, counting the number of reopened holes. The efficacy of control by whole wheat toxic baits was determined ...

Directed acyclic graphs have been used fruitfully to represent causal structures (Pearl 1988). However, in the social sciences and elsewhere models are often used which correspond both causally and statistically to directed graphs with directed cycles (Spirtes 1995). Pearl (1993) discussed predicting the effects of intervention in models of this kind, so-called linear non-recursive structural e...