Oppositions-Ephemeride des Planeten (24) Themis

Limits to Ice on Asteroids (24) Themis and (65) Cybele

We present optical spectra of (24) Themis and (65) Cybele, two large mainbelt asteroids on which exposed water ice has recently been reported. No emission lines, expected from resonance fluorescence in gas sublimated from the ice, were detected. Derived limits to the production rates of water are . 400 kg s (5σ), for each object, assuming a cometary H2O/CN ratio. We rule out models in which a l...

Patent Oppositions

In recent years, patent protection has extended into new areas, giving rise to serious concern about the lack of clear guidelines for patentability. We analyze the effect of introducing a patent opposition process that would allow patent validity to be challenged directly after a patent is granted. In many cases, such a system would avoid costly litigation at a later date. In other cases, the o...

Nested Oppositions

Oppositions and quantum mechanics

In this paper we deal with two applications of the square of opposition to controversial issues in the philosophy of quantum mechanics. The first one concerns the kind of opposition represented by states in superposition. A superposition of “spin up” and “spin down” for a given spatial direction, for instance, is sometimes said to originate particular kinds of opposition such as contradictorine...

Oppositions in Rough Set Theory

The role of opposition in rough set theory is laid bare. There are two sources which generate oppositions in rough sets: approximations and relations. In the former case, we outline a hexagon and a cube of oppositions. In the second case, we define a classical square of oppositions and also a tetrahedron when considering the standpoint of two agents.