We consider a physical system constituted by a finite chain of point masses consecutively linked by linear springs and dashpots. At one of the end points acts an external control force aligned with the chain and the system is observable by the position of the other end point. We show that, whatever is the number of the point masses, if the sequence of the elastic constants is proportional to th...

Minisuperspace Quantum Cosmology is an approach by which it possible to infer initial conditions for dynamical systems can suitably represent observable and non-observable universes. Here we discuss theories of gravity which, from various points view, extend Einstein’s General Relativity. Specifically, the Hamiltonian formalism f(R), f(T), f(G) gravity, with R, T, G being curvature, torsion Gau...

An edge-colored directed graph is observable if an agent that moves along its edges from node to node is able to determine his position in the graph after a sufficiently long observation of the edge colors, and without accessing any information about the traversed nodes. When the agent is able to determine his position only from time to time, the graph is said to be partly observable. Observabi...

The idea that reciprocal cooperation can be obtained in a one-shot game if the players observe each other’s strategies before taking action has attracted many authors. From a strictly logical perspective, however, there cannot be such games. Nevertheless, there are games in which each player can observe which class, out of a collection of classes smaller than the number of strategies, the oppon...

The aim of the present study was to investigate in detail the variation of the intrinsic spatial resolution across the useful field of view (UFOV) of gamma-cameras and to explore whether this variation could lead to observable effects in clinical images. Two gamma-cameras were used, without their collimators, to acquire 560 (99m)Tc point source images at different points across their UFOVs, in ...

Abstract. Whereas the traditional liveness property for Petri nets guarantees that each transition can always occur again, observable liveness requires that, from any reachable marking, each observable transition can be forced to fire by choosing appropriate controllable transitions; hence it is defined for Petri nets with distinguished observable and controllable transitions. We introduce obse...

This paper reviews the developmental/reproductive toxicity of commercial polychlorinated biphenyl (PCB) mixtures in animals and reports on the "no-observable-adverse-effect levels" (NOAELs) and "lowest-observable-adverse-effect levels" (LOAELs) from these studies. Identification of the lowest effective doses for reproductive toxicity of PCB mixtures is difficult because a variety of reproductiv...