Paleobotanical evidence for near present-day levels of atmospheric Co2 during part of the tertiary.

Understanding the link between the greenhouse gas carbon dioxide (CO(2)) and Earth's temperature underpins much of paleoclimatology and our predictions of future global warming. Here, we use the inverse relationship between leaf stomatal indices and the partial pressure of CO(2) in modern Ginkgo biloba and Metasequoia glyptostroboides to develop a CO(2) reconstruction based on fossil Ginkgo and Metasequoia cuticles for the middle Paleocene to early Eocene and middle Miocene. Our reconstruction indicates that CO(2) remained between 300 and 450 parts per million by volume for these intervals with the exception of a single high estimate near the Paleocene/Eocene boundary. These results suggest that factors in addition to CO(2) are required to explain these past intervals of global warmth.

An interface to enhance mobility for people with hemispatial neglect.

The objective was to develop and test a control interface to enable people with hemispatial neglect to maneuver a powered wheelchair with increased attention to their environment. A single case study was conducted using a female (aged 72 years) who had a right cerebro vascular accident five years earlier. She drove a powered wheelchair through 20 different test courses (mazes) while a computer recorded frequency of looking to the left (left checks) and an observer recorded visual targets missed and wheelchair collisions with walls and obstacles. The Mann-Whitney test was used to determine significant differences in left checks, left collisions, right collisions, and percent left checks targets missed between baseline and strategy phases. With the interface strategy, the subject significantly increased the number of left checks and missed fewer left targets in the test course. These results indicate that a powered-wheelchair control interface shows promise in enabling people with mild hemispatial neglect to maneuver a powered chair with greater environmental awareness and ease.

A new basis for recognizing the paleocene/eocene boundary in Western interior north america.

Fossil pollen grains from Paleocene-Eocene rocks of the Bighorn Basin of Wyoming allow important sequences of terrestrial vertebrate fossils to be correlated with standard marine microfossil zonations. The Paleocene/Eocene boundary as based on pollen evidence falls within the Wasatchian land mammal age, much higher than the boundary used by some fossil mammal workers. This discrepancy partly results from multiple definitions of the Paleocene/Eocene boundary but may also indicate faulty mammal-based correlations to the type Sparnacian of France.