Information-theoretic sensitivity analysis: a general method for credit assignment in complex networks

Most systems can be represented as networks that couple a series of nodes to each other via one or more edges, with typically unknown equations governing their quantitative behaviour. A major question then pertains to the importance of each of the elements that act as system inputs in determining the output(s). We show that any such system can be treated as a ‘communication channel’ for which the associations between inputs and outputs can be quantified via a decomposition of their mutual information into different components characterizing the main effect of individual inputs and their interactions. Unlike variance-based approaches, our novel methodology can easily accommodate correlated inputs

Mass transfer and star formation in the early-type galaxy of a mixed pair, am 0327-285

We present evidence for a young stellar population component in the early-type member of the E+S galaxy pair AM 0327-285. This young population is consistent with the occurrence of cross-fueling in this interacting system. We used spectroscopy, optical imaging, IRAS data, and stellar population synthesis to study the stellar content in the early-type galaxy. We also attempted to date episodes of star formation in its nuclear region, from population synthesis and basic dynamical considerations. The dominant population is old and metal-rich ([Z/Z]Θ=0.3) while ~ 10% of the flux at 5870 Å arises from a superimposed young stellar population with age <_ 5 x 10⁸ yr. This age is close to several estimates of the characteristic timescale of the interaction, suggesting that the mass influx associated with this star formation occurred as a result of an earlier phase of the interaction and not as a result of the present geometry of the pair

Mass transfer and star formation in the early-type galaxy of a mixed pair, am 0327-285

We present evidence for a young stellar population component in the early-type member of the E+S galaxy pair AM 0327-285. This young population is consistent with the occurrence of cross-fueling in this interacting system. We used spectroscopy, optical imaging, IRAS data, and stellar population synthesis to study the stellar content in the early-type galaxy. We also attempted to date episodes of star formation in its nuclear region, from population synthesis and basic dynamical considerations. The dominant population is old and metal-rich ([Z/Z]Θ=0.3) while ~ 10% of the flux at 5870 Å arises from a superimposed young stellar population with age <_ 5 x 10⁸ yr. This age is close to several estimates of the characteristic timescale of the interaction, suggesting that the mass influx associated with this star formation occurred as a result of an earlier phase of the interaction and not as a result of the present geometry of the pair