Polar Bear, Polar Bear

The Stream Cipher Polar Bear

We propose a new stream cipher called “Polar Bear”. It combines constructions used successfully in other situations. The key initialization uses Rijndael, the steady state uses a dynamic table as in RC4 and we guarantee a long period through the use of a linear feedback shiftregister. The efficiency for short messages is better than that of RC4 while for long messages Polar Bear is about a fact...

The Polar Bear — Ursus maritimus

Is polar bear hair fiber optic?

New direct measurement of high optical attenuation rates in polar bear hairs--2-8 dB/mm in the visible--and reanalysis of the data of Tributsch et al. [Sol. Energy Mater. 21, 219 (1990)] seem to rule out the UV waveguiding proposed by Grojean et al. [Appl. Opt. 19, 339 (1980)]. The case against fiber-optic polar bear hairs is summarized, and four conditions are given that any variation of the m...

Polar Bear Population Status in the Southern Beaufort Sea

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Biomechanical Consequences of Rapid Evolution in the Polar Bear Lineage

The polar bear is the only living ursid with a fully carnivorous diet. Despite a number of well-documented craniodental adaptations for a diet of seal flesh and blubber, molecular and paleontological data indicate that this morphologically distinct species evolved less than a million years ago from the omnivorous brown bear. To better understand the evolution of this dietary specialization, we ...