Scientists Spy on Treefrogs Using Plastic Pipes in Trees

Spy Game in trees and grids

In the Spy game, a spy is placed first at some vertex of a graph G. Then, k > 0 guards are also occupying some vertices of G. At each turn, the spy moves at speed s ≥ 2, i.e., along at most s edges and then, each guard moves at speed 1. The spy and any number of guards may occupy the same vertex. The goal of the guards is to control the spy at distance d ≥ 0, i.e., to ensure that, at every turn...

Modeling of Transient Flow in Plastic Pipes

We present a numerical code for calculating transient flow in plastic pipes, especially in the polyethylene pipe, to analysis water hammer phenomena. The set partial differential equations to be solved is obtained using conservation laws and behavior for the fluid and the pipe wall, associated with constitutive equations of the two media, and relationships compatibility of interfaces on velocit...

Permeation of benzene, trichloroethene and tetrachloroethene through plastic pipes

Spy-Game on Graphs

We define and study the following two-player game on a graph G. Let k ∈ N∗. A set of k guards is occupying some vertices of G while one spy is standing at some node. At each turn, first the spy may move along at most s edges, where s ∈ N∗ is his speed. Then, each guard may move along one edge. The spy and the guards may occupy same vertices. The spy has to escape the surveillance of the guards,...

How embryos escape from danger: the mechanism of rapid, plastic hatching in red-eyed treefrogs.

Environmentally cued hatching allows embryos to escape dangers and exploit new opportunities. Such adaptive responses require a flexibly regulated hatching mechanism sufficiently fast to meet relevant challenges. Anurans show widespread, diverse cued hatching responses, but their described hatching mechanisms are slow, and regulation of timing is unknown. Arboreal embryos of red-eyed treefrogs,...