Loggerhead sea turtle used on every confirmed nest to prevent excavation by resident red foxes. A new concern with the steel cage technique is interference with the normal development of the nestlings' magnetic sense due to the use of ferrous wire, which may disrupt the turtles' ability to navigate properly. Efforts are underway to find a nonmagnetic material that will prevent predators gnawing through the barrier. Up to 40% of nesting females around the world have wounds believed to come from shark attacks. Infectious bacteria such as "Pseudomonas" and "Salmonella" attack loggerhead hatchlings and eggs. Fungi such as "Penicillium" infect loggerhead sea turtle
History of manifolds and varieties spaces with a differentiable or topological structure, while "variety" refers to spaces with an algebraic structure, as in algebraic varieties. In Romance languages, manifold is translated as "variety" – such spaces with a differentiable structure are literally translated as "analytic varieties", while spaces with an algebraic structure are called "algebraic varieties". Thus for example, the french word "" means topological manifold. In the same vein, the Japanese word "" (tayōtai) also encompasses both manifold and variety. ("" (tayō) means various.) Ancestral to the modern concept of a manifold were several important results of 18th and 19th century mathematics. The oldest