Imagine that you are the owner of several art galleries and that you are in the process of hiring people to guard one of them. Unfortunately, with so many in your possession, you seem to have forgotten the exact shape of this particular one. In fact, all you can remember is that the art gallery is a polygon with n sides. Of course, guards have the capacity to turn around a full 360◦ and can see...

We introduce the notion of a normal gallery, a gallery in which any configuration of guards that visually covers the walls necessarily covers the entire gallery. We show that any star gallery is normal and any gallery with at most two reflex corners is normal. A polynomial time algorithm is provided deciding if, for a given gallery and a finite set of positions within the gallery, there exists ...

Fine particle clogging and faunal bioturbation are two key processes co-occurring in the hyporheic zone that potentially affect exchange through modifications sediment structure of streambeds. Clogging results from excessive fine infiltration deposition rivers, it is known to decrease matrix porosity reduce permeability. Faunal activity may compensate for negative effect by reworking sediment, ...

Nitrate enhanced bioremediation solubility of oxygen. Nitrate is more soluble than oxygen and is less expensive. The significance of the nitrate bioremediation at Traverse City is that the concentration of nitrate used in the bioremediation was below Federal drinking water standards. that when nitrate and nutrients were added, they could be evenly distributed In order to determine the effects o...