Upside-down swimming behaviour of free-ranging narwhals

Upside-down swimming catfish and utricle

s The upside-down swimming catfish (Synodontis nigriventris) has unique behavior, i.e., it frequently shows a stable upside-down posture during swimming and resting. To examine whether the unique postural control in S. nigriventris results from the characteristics of the vestibular organ, we observed the morphological aspects of the otolith and the orientation of sensory hair cells in the utric...

Management of suicidal behaviour: is the world upside down?

Swimming Behaviour and Energetics of Free-ranging Sharks: New Directions in Movement Analysis

There is now a general agreement that sharks, and pelagic sharks in particular, are facing widespread declines in population level due to fishing activity (Pauly et al., 2003). Recent studies suggest dramatic reductions in relative abundance of up to 80% have occurred in as little as 15 years for some species (Baum et al., 2003; Myers et al., 2006), trends most likely linked to greater target c...

Biosonar behaviour of free-ranging porpoises.

Detecting objects in their paths is a fundamental perceptional function of moving organisms. Potential risks and rewards, such as prey, predators, conspecifics or non-biological obstacles, must be detected so that an animal can modify its behaviour accordingly. However, to date few studies have considered how animals in the wild focus their attention. Dolphins and porpoises are known to activel...

Ramanujan Series Upside-down

We prove that there is a correspondence between Ramanujan-type formulas for 1/π and formulas for Dirichlet L-values. Our method also allows us to reduce certain values of the Epstein zeta function to rapidly converging hypergeometric functions. The Epstein zeta functions were previously studied by Glasser and Zucker.