Hummingbirds use compensatory eye movements to stabilize both rotational and translational visual motion.

To maintain stable vision, behaving animals make compensatory eye movements in response to image slip, a reflex known as the optokinetic response (OKR). Although OKR has been studied in several avian species, eye movements during flight are expected to be minimal. This is because vertebrates with laterally placed eyes typically show weak OKR to nasal-to-temporal motion (NT), which simulates typical forward locomotion, compared with temporal-to-nasal motion (TN), which simulates atypical backward locomotion.

Encoding of Global Visual Motion in the Avian Pretectum Shifts from a Bias for Temporal-to-Nasal Selectivity to Omnidirectional Excitation across Speeds.

The pretectum of vertebrates contains neurons responsive to global visual motion. These signals are sent to the cerebellum, forming a subcortical pathway for processing optic flow. Global motion neurons exhibit selectivity for both direction and speed, but this is usually assessed by first determining direction preference at intermediate velocity (16-32°/s) and then assessing speed tuning at the preferred direction.

The spatiotemporal richness of hummingbird wing deformations.

Animals exhibit an abundant diversity of forms, and this diversity is even more evident when considering animals that can change shape on demand. The evolution of flexibility contributes to aspects of performance from propulsive efficiency to environmental navigation. It is, however, challenging to quantify and compare body parts that, by their nature, dynamically vary in shape over many time scales.

Elevated Anti-Xa in the Setting of Prophylactic Unfractionated Subcutaneous Heparin Administration.

Venous thromboembolism prophylaxis with subcutaneous unfractionated heparin or low molecular weight heparin is a common practice in hospitalized patients. Typically, prophylactic doses of these medications have poor bioavailability and thus do not reach therapeutic serum concentrations. However, in certain circumstances, heparin binding proteins may become saturated.