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. 2020 Oct 14;15(10):e0239622. doi: 10.1371/journal.pone.0239622

Fig 4. Biplot of the principal component analysis of the USAPS.

Fig 4

USAPS–Unesp-Botucatu sheep acute composite pain scale. Confidence ellipses were built according to the perioperative moments and pain scores. Moments: M1—preoperative; M2—postoperative, before rescue analgesia; M3—postoperative, after rescue analgesia; M4 - 24h after surgery. Ellipses were constructed according to the moments of pain assessment (M1—green, M2—red, M3 –blue, and M4—yellow). The ellipse referring to the time when sheep were in severe pain (M2) was positioned at the right side of the figure; on the opposite side are the ellipses corresponding to the moments in which sheep were probably not in pain (M1 and M4). The moment of moderate pain (M3) is positioned in the middle. All items on the scale are influenced by moments of pain (M2 and M3) since their vectors are positioned in the direction of these ellipses.