The retinae of many bird species contain a depression with high photoreceptor density known as the fovea. Many species of raptors have two foveae, a deep central fovea and a shallower temporal fovea. Birds have six types of photoreceptors: rods, active in dim light, double cones that are thought to mediate achromatic discrimination, and four types of single cones mediating color vision. To maxi...

Gouvêa and Mazur made a precise conjecture about slopes of modular forms. Weaker versions of this conjecture were established by Coleman and Wan. In this Note, we exhibit examples contradicting the full conjecture as it currently stands. To cite this article: K. Buzzard, F. Calegari, C. R. Acad. Sci. Paris, Ser. I 338 (2004).  2004 Académie des sciences. Published by Elsevier SAS. All rights r...

Observations of antipredator behavior in two troops of free-ranging Lemur catta were made during a 13-month study o f L. cattafeeding ecology. Both responses to and frequency o f encounters with other species were recorded. Ringtailed lemur antipredator calls differentiated between terrestrial and avian predators. L. catta responded to the Madagascar harrier hawk (Polyboroides radiatus) and the...

Intraguild predation (IGP) is a commonly recognized mechanism influencing the community structure of predators, but the complex interactions are notoriously difficult to disentangle. The mesopredator suppression hypothesis predicts that a superpredator may either simultaneously repress two mesopredators, restrain the dominant one and thereby release the subdominant mesopredator, or elicit diffe...

A hollow cylinder apparatus was used to investigate the inherent anisotropy and membrane penetration of Leighton Buzzard sand test-specimens. The degree of inherent anisotropy was found to be independent of the mean effective stress but dependent on the initial relative density of the test-specimen. In the vertical-tohorizontal directions, the degree of inherent anisotropy decreases with increa...

Abstract Statistical data on aircraft collisions with birds of prey (Falconiformes and Accipitriformes) are analyzed. The basis the analysis was results study at Severtsov Institute Ecology Evolution, Russian Academy Sciences (IPEE RAS). reasons factors attracting to airfields considered. In period from 2005 2022, seven species involved in 29 were identified. largest number birdstrikes occur Co...

The McMullen-Sullivan holomorphic motion for topologically conjugate, complex polynomials with connected Julia set follows level sets of the Böttcher coordinate. The Buzzard-Verma holomorphic motion for hyperbolic, unstably connected, polynomial diffeomorphisms of C follows level sets of the Bedford-Smillie solenoid map. It follows that this solenoid map is a conjugacy for those Hénon maps that...