Experimental Reintroduction of American Hart’s-Tongue Fern (Asplenium scolopendrium var. americanum): Factors Affecting Successful Establishment of Transplants

This study analyzed biological and microclimatic factors affecting the post-reintroduction survival and growth of laboratory-propagated American hart’s-tongue ferns (Asplenium scolopendrium var. americanum, AHTF), a rare and threatened fern species with a fragmented distribution across the eastern United States and Canada. In total, 1,925 AHTF transplants, representing four life history stages (protonemata, gametophytes, sporelings, and immature sporophytes) were reintroduced into three sites determined to be ideal habitats within Onondaga County, New York. Factors that resulted in higher rates of survival included more rigorous acclimatization of transplants, better transplant vigor at the time of transplanting, and higher humidity at reintroduction sites. Analysis of wind speed and direction provided implications of low spore dispersal, and therefore low gene flow, between extant AHTF populations. Insights from this research contribute to a growing, yet still understudied, body of knowledge regarding fern species reintroductions and inform best practices for future AHTF reintroductions

High-Speed Noninvasive Eye-Tracking System

The figure schematically depicts a system of electronic hardware and software that noninvasively tracks the direction of a person s gaze in real time. Like prior commercial noninvasive eye-tracking systems, this system is based on (1) illumination of an eye by a low-power infrared light-emitting diode (LED); (2) acquisition of video images of the pupil, iris, and cornea in the reflected infrared light; (3) digitization of the images; and (4) processing the digital image data to determine the direction of gaze from the centroids of the pupil and cornea in the images. Relative to the prior commercial systems, the present system operates at much higher speed and thereby offers enhanced capability for applications that involve human-computer interactions, including typing and computer command and control by handicapped individuals,and eye-based diagnosis of physiological disorders that affect gaze responses