With no explanation, label text_A→text_B with either "not_related" or "related".
text_A: John Connally was a Secretary of the Treasury.
text_B: Canopy conductance , commonly denoted , is a dimensionless quantity characterizing radiation distribution in tree canopy .. dimensionless quantity. dimensionless quantity. canopy. Canopy ( biology ). By definition , it is calculated as a ratio of daily water use to daily mean vapor pressure deficit -LRB- VPD -RRB- .. vapor pressure deficit. vapor pressure deficit. Canopy conductance can be also experimentally obtained by measuring sap flow and environmental variables .. Stomatal conductance may be used as a reference value to validate the data , by summing the total stomatal conductance of all leaf classes within the canopy .. canopy. Canopy ( biology ). Stomatal conductance. Stomatal conductance. leaf classes. Leaf shape
not_related.