Spiralling out
نویسندگان
چکیده
منابع مشابه
Spiralling out
by human activity is easily understood, though difficult to halt: the spectacular decline in once-common species that ranged over vast areas of diverse habitats proved initially a much more difficult problem to understand. An example of this is the extraordinary reduction in numbers of three Asian vultures — the Oriental white-backed (Gyps bengalensis), long-billed (Gyps indicus) and slender-bi...
متن کاملFolding and Spiralling: The Word View
We show that for every n there are two simple curves on the torus intersecting at least n times without the two curves folding or spiralling with respect to each other.
متن کاملSpiralling and Folding: The Word View
We show that for every n there are two simple curves on the torus intersecting at least n times without the two curves folding or spiralling with respect to each other. On the other hand, two simple curves in a punctured plane that intersect at least n times (and do not create any empty bigons) must either form a spiral of depth d or a fold of width cn/(d + 1) − 1, where c only depends on the n...
متن کاملTotal Curvature and Spiralling Shortest Paths
This paper gives a partial confirmation of a conjecture of Agarwal, Har-Peled, Sharir, and Varadarajan that the total curvature of a shortest path on the boundary of a convex polyhedron in R3 cannot be arbitrarily large. It is shown here that the conjecture holds for a class of polytopes for which the ratio of the radii of the circumscribed and inscribed ball is bounded. On the other hand, an e...
متن کاملSpiralling and Folding: The Topological View
For every n, we construct two arcs in the four-punctured sphere that have at least n intersections and which do not form spirals. This is accomplished in several steps: we first exhibit closed curves on the torus that do not form double spirals, then arcs on the four-punctured torus that do not form spirals, and finally arcs in the four-punctured sphere which do not form spirals.
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Current Biology
سال: 2006
ISSN: 0960-9822
DOI: 10.1016/j.cub.2006.01.036