Abstract: The present invention relates to methods and means for producing nitrogenase polypeptides in the mitochondria of plant cells.

Abstract: Systems and methods for identifying equivalent content items. A computer system may receive a description of a first content item, the description of the first content item comprising a first set of values for a plurality of content item characteristics. The computer system may compare the first content item to each of a plurality of content items. The comparing may comprise, for each combination of the first content item and one of the plurality of content items, identifying any characteristics from the plurality of content item characteristics for which first content item and the one of the plurality of content items has equivalent values. The computer system may identify at least one content item selected from the plurality of content items. The first content item and the at least one content item have equivalent values for a predetermined pattern of the plurality of content item characteristics.

Abstract: Systems and methods for updating user play lists in a content provider service. A computer system may receive indications of a plurality of content items to be removed from a digital content library of the content provider service. The computer system may query a user database to identify a plurality of user play lists comprising a reference to a first content item selected from the plurality of content items. Each of the plurality of user play lists may be associated with a user of the content provider service. The computer system may identify a second content item that is equivalent to the first content item. The computer system may update at least one user play list selected from the plurality of user play lists to replace references to the first content item with references to the second content item.

Abstract: Systems and methods for identifying equivalent content items. A computer system may receive a description of a first content item, the description of the first content item comprising a first set of values for a plurality of content item characteristics. The computer system may compare the first content item to each of a plurality of content items. The comparing may comprise, for each combination of the first content item and one of the plurality of content items, identifying any characteristics from the plurality of content item characteristics for which first content item and the one of the plurality of content items has equivalent values. The computer system may identify at least one content item selected from the plurality of content items. The first content item and the at least one content item have equivalent values for a predetermined pattern of the plurality of content item characteristics.