Cutlery and Allied Trades Research Association knowledge which is available to everyone on a competitive fee paying basis, however CATRA will enter into dialogue with consumers and users of cutlery, knives and tools where their expertise may be of help, on a free of charge basis. Petersen's Bowhunting magazine uses CATRA to measure sharpness of arrowheads. CATRA manufactures a wide range of special purpose equipment including knife and cutlery testing machines and knife sharpening systems including the CATRAHONE and CATRASHARP machines Cutlery and Allied Trades Research Association Cutlery and Allied Trades Research Association (CATRA) is an internationally known research and technology organisation in Sheffield, England which
David ben Judah Messer Leon David ben Judah Messer Leon David ben Judah Messer Leon (c. 1470 in Venice – c. 1526 in Salonica) was an Italian rabbi, physician and writer, who defended the value of secular disciplines and the Renaissance humanities as an important part of traditional Jewish studies. David ben Judah was educated at Naples in the school of his father, Judah Messer Leon, author of "Libnat ha-Sappir", and received at the age of eighteen his rabbinical diploma from German and French Talmudic authorities. Soon afterward he went to Padua, where he studied under Judah Minz, who granted him a new rabbinical diploma.