Is Information Content a Single, Static Quantity?

Before information may be measured it must first manifest as a specific kind of information, and that manifestation always occurs within a fixed context. If any critical element of the context is changed, the information that is manifested also changes. The implication of that is significant: information is \emph{not} a single, static entity but instead is a variable, dynamic entity that acquires fixed definition only within a context.

Total and Static Quantity Measurements in Unsteady Flow — Effect of Unsteadiness

The effects of unsteadiness both on high-response dynamic measurements and on time-averaged measurements with slow-response probes are analytically investigated separately from the response characteristics of the measuring system. The approach is based on physical similarity and dimensional analysis. The potential errors from flow unsteadiness and the major parameters which influence the measurement results are discussed. In the case of five sensor spherical probes a quantitative investigation for inviscid, incompressible, irrotational flow is carried out with the help of potential theory.

Dispersion formulas for real- and imaginary-frequency-dependent hyperpolarizabilities

The dynamic second hyperpolarizability for real frequencies, [Formula: see text] in the limit ωi → 0 can be expressed as [Formula: see text] where ωL2 = ωσ2 + ω12 + ω22 + ω32 and [Formula: see text] is the frequency-independent (static) quantity; the parallel sutsscript [Formula: see text] indicates that the polarization and electric fields all lie along the same axis. In this paper the coefficient [Formula: see text] is evaluated exactly for the H atom and very accurately for H−, He, and Li+. A similar analysis is carried out for [Formula: see text] in the limit ω → ∞. Key words: nonlinear optics, hyperpolarizabilities, dispersion formulas.On peut exprimer la deuxième hyperpolarisabilité dynamique de fréquences réelles, [Formula: see text] dans la limiteωi → 0, peut être exprimée sous la forme [Formula: see text], dans laquelle ωL2 = ωσ2 + ω12 + ω22 + ω32 et [Formula: see text] est la quantité (statique) indépendant de la fréquence; l'indice parallèle [Formula: see text] indique que la polarisation et les champs électriques sont situés dans le même axe. Dans ce travail, on a fait une évaluation exacte de [Formula: see text] pour l'atome d'hydrogène et d'une façon précise pour H−, He et Li+. On a effectué une analyse semble pour [Formula: see text]dans la limite ω → ∞. Mots clés : optique non linéaire, hyperpolarisabilités, formules de dispersion. [Traduit par la rédaction]

Bestimmung des zerebralen Blutflusses mittels des 81 Rb/81 mKr-Generatorsystems

A method is being developed which not only measures cerebral blood flow as a static quantity but also its changes with time. For that purpose a semiconductor device ascertains the proportion of intracerebral81 Rb and 81mKr activities. By opening the haemato-encephalic barrier in animal experiments a sufficient concentration of intracerebral81 Rb could be attained and the modified blood circulation after step-wise ligature of all brain arteries brought into relation to the corresponding Rb/Kr quotient. Over the range from undisturbed to completely interrupted cerebral blood flow this quotient varied up to 25% of its initial value.