Ista'oorta aloy waa bir ay bir bir ah oo leh walxo kala duwan oo wadarta guud ee u dhexeeya 1.0% iyo 50% miisaanka si loo wanaajiyo hantida farsamada. Stels stels waxaa loo kala jabay laba kooxood: stors-ka hoose ee alfoonka yar iyo stores-ka sare ee loo yaqaan 'potoy'. Farqiga u dhexeeya labada waa la muransan yahay. Smith iyo Hashemi ayaa qeexaya farqiga u dhexeeya 4.0%, halka Degardo, et al., Qeexdaa boqolkiiba 8.0%. [1] [2] Inta badan, weedha "aloy bir" waxaa loola jeedaa stors-ka yar-yar.