Keratinous horn sheaths of the extinct Harrington's mountain goat, Oreamnos harringtoni, were recovered at or near the surface of dry caves of the Grand Canyon, Arizona. Twenty-three separate specimens from two caves were dated nondestructively by the tandem accelerator mass spectrometer (TAMS). Both the TAMS and the conventional dates indicate that Harrington's mountain goat occupied the Grand...

Some scientists consider the loss of the American chestnut from forests in the eastern United States as one of the greatest forest ecological disasters in the 20th century. The American Chestnut Foundation has been attempting to restore chestnut by backcrossing blight-resistant Chinese chestnut to American chestnut and selecting those strains with blight resistance. Third-generation backcross s...

Marine Isotope Stage (MIS) 5 and 4 are periods of major cultural innovations in the Middle Stone Age (MSA) southern Africa. While extensive data is available for coast, far less known about interior, particular its central plateau. This likely due to large geographic extent this area a general paucity caves rock shelters that can provide long stratigraphic sequences environmental records. The l...

Seven new species of the spider genus Ochyrocera from cave areas in Floresta Nacional de Carajás (state of Pará, northern Brazil) are described: Ochyrocera varyssp. n., Ochyrocera atlachnachasp. n., Ochyrocera laracnasp. n., Ochyrocera aragoguesp. n., Ochyrocera misspidersp. n., Ochyrocera charlottesp. n., and Ochyrocera ungoliantsp. n. Two groups of the species are discussed, the quinquivittat...

In the aftermath of a nuclear attack, shelters can offer potentially important protection. How well they fill that role depends on a set of interdependent decisions made by the individuals and organizations that must prepare and use them. We look at three such decisions. For each, we begin with formal analysis of the consequences expected from different possible actions. Those analyses are, the...