Uniform definitions of term are predicated on a uniform method of determining gestational age. The work group provided a method for determination of gestational age ( 5 ) that, like other similar methods ( 6 ), focused on a hierarchy of clinical and ultrasonographic criteria. Individual methods may differ in the details of when and how ultrasonographic biometry should be used to change estimated date of delivery based on last menstrual period; however, it is not the purpose of this document to establish the priority of one method over another. The College and SMFM are working with other expert groups to establish evidence-based consensus on criteria for determining gestational age.
There are many theoretical ideas behind abstract art. While some have taken the idea of 'art for art’s sake' (that art should be purely about the creation of beautiful effects), others have proposed art can or should be like music, in that just as music is patterns of sound, art’s effects should be created by pure patterns of form, colour and line. The idea, derived from the ancient Greek philosopher Plato, that the highest form of beauty lies not in the forms of the real world but in geometry, is also used in discussion of abstract art, as is the idea that abstract art, since it does not represent the material world, can be seen to represent the spiritual.