Kinematics of diving Atlantic puffins (Fratercula arctica L.): evidence for an active upstroke.
To examine the propulsion mechanism of diving Atlantic puffins (Fratercula arctica), their three-dimensional kinematics was investigated by digital analysis of sequential video images of dorsal and lateral views. During the dives of this wing-propelled bird, the wings are partly folded, with the handwings directed backwards. The wings go through an oscillating motion in which the joint between the radius-ulna and the hand bones leads the motion, with the wing tip following. There is a large rotary motion of the wings during the stroke, with the wings being pronated at the beginning of the downstroke and supinated at the end of the downstroke/beginning of the upstroke. Calculated instantaneous velocities and accelerations of the bodies of the birdsAs Beyoncé’s art has grown outwardly political and pro-black throughout the decade, she has increasingly called upon African-born artists to participate in and inform her work. She did this with Tofo Tofo, the Mozambican pantsula dancers who appeared in her 2011 “Run the World (Girls)” video. In her self-titled era, she sampled Nigerian feminist writer Chimamanda Ngozi Adichie on 2013’s “***Flawless,” and Griot vocalist Ismael Kouyaté on the Afro-inspired “Grown Woman.” The Lemonade film, which was threaded by excerpts of Somali-British poet Warsan Shire’s work, featured ritual Yoruba body makeup work by Nigerian-American artist Laolu Senbanjo. During her 2018 set at Global Citizen Fest South Africa, she recruited a local choir to add Zulu backing vocals to a performance of “Halo.” And later that year, her headlining Coachella