definiens: means, with respect to a particular Collaboration Target, ( a ) with respectto the first Contract Year, the period beginning on the date such Collaboration Target is accepted into theCollaboration ( or, in the case of the first Co\laboration Target, the Effective Date ) and ending on-4 - December 31 ofthe calendar year in which such acceptance takes place ( which.in the case of the firstCollaboration Target is December 31, 2006 ) ( such period, the ), and ( b ) with respectto cach subsequcnt Contract Year, the twelve ( 12 ) month pcriod bcginning on the day following the endof the First Contract Year and each succceding twelve ( 12 ) month period thereafter . Each Contract Year(other than the First and last Contract Years, as applicable ) shall bc.divided into four ( 4 ) comprised of successive three ( 3 ) month periods . In the First Contract Year, the first ContractQuarter shall begin on the first day of the First Contract Year and sball end on the last day of the calendarquarter in which the relevant Collaboration Target is accepted into the Collaboration ( which in the case ofthe first Collaboration Target is December 31,2006 )