frankly consider him a great virtuoso, " said Italian painter Guercino of Rembrandt van Rijn. Guercino (1591–1666) was referring to the legendary master not as painter or portraitist but as etcher because it was etchings that built Rembrandt's reputation during his lifetime (1). The fi rst to fully exploit this technique, which dates back to 14th-century armor ornamentation, he left behind some...

“K thyself” resonated with Rembrandt van Rijn. More than any other artist of his caliber at any time, he explored his own image in as many as 90 self-portraits, some 60 of them paintings, an extraordinary record of self-examination. He was so frank with his depictions he could not have been motivated by narcissism. He may have taken up portraiture for its connection to history painting, a lifel...

This two-part article reviews selected problems in the theory of cellular automata, aiming to locate this theory with respect to the theory of complex systems in general. To appear in the journal "Complexity". 1 Figure 1: De schelp (conus marmoreus) This Rembrandt (1650) etching describes a shell bearing markings similar to those produced by some cellular automata.

The surface of Mercury has been heavily modified by impact cratering and volcanic plains since the initial formation of its lithosphere and crust. As in the case of the Moon, the origin of early plains deposits has been difficult to determine because ponded impact basin ejecta and impact melt deposits can mimic the topography and texture of extrusive volcanic plains. In order to understand bett...

Mercury’s Debussy Quadrangle (H14) lies between 0–90° E and 22.5–65° S. Here we use MESSENGER data to produce the first geological map of this quadrangle at a scale 1:3,000,000, based on linework completed 1:300,000. We distinguish crater units plains units. For compatibility with historic recent maps other Mercury quadrangles, global (Main Map), have made two versions map, craters classified a...