Lottia digitalis Point on the California coast, "L. digitalis" coexists with the similar species, "Lottia scabra", but each occupies a slightly different habitat. "L. digitalis" tends to occupy vertical rock faces or overhangs and certain horizontal ones clothed by algae and barnacles. "L. digitalis" clump together more often, prefer wave-exposed areas, occupy sites further up the shore and are seldom found in rock pools. Both species move about freely when the tide is up but "L. digitalis" settles in a different location at each low tide whereas "L. scabra" tends to home to the same spot. "L. scabra" has a more rugged
Derive (computer algebra system) Derive (computer algebra system) Derive was a computer algebra system, developed as a successor to muMATH by the Soft Warehouse in Honolulu, Hawaii, now owned by Texas Instruments. Derive was implemented in , also by Soft Warehouse. The first release was in 1988 for DOS. It was discontinued on June 29, 2007 in favor of the TI-Nspire CAS. The last and final version is Derive 6.1 for Windows. Since Derive required comparably little memory, it was suitable for use on older and smaller machines. It was available for the DOS and Windows platforms and was used also in TI pocket