Given a passage classify if the passage has a definite objective/aim/goal or not. Output '1' if the passage has a defininte objective/aim/goal and output '0' if the passage does not have a definite objective/aim/goal.

To determine whether increased sequence variation occurs in regions of endogenous HIV-1 targeted by HIV-1-specific CD4 T cells. The presence of increased variation would be suggestive of immune evasion by HIV-1.', 'We performed a cross-sectional study of untreated HIV-1-infected subjects measuring HIV-1-specific interferon (IFN)-gamma-secreting CD4 T-cell responses against epitopes in Gag p17 and p24 and concurrent endogenous plasma HIV-1 RNA epitope sequence variation.', 'CD8- depleted IFNgamma enzyme-linked immunospot assays were used to identify regions of HIV-1 Gag recognized by CD4 T cells. Reverse transcriptase polymerase chain reaction and TA cloning were used to sequence endogenous plasma HIV-1 virus and identify variants.', 'CD4 T-cell epitopes in Gag p17 and p24 were identified in 5 individuals, and concurrent sequence information on endogenous HIV-1 was obtained in 4 of these individuals. Endogenous plasma HIV-1 RNA sequencing revealed no intrapatient amino acid sequence variation through identified epitopes.
1