Distribution of Recreational Boating across Lakes: Do Landscape Variables Affect Recreational Use?

1. Because people impact lake ecosystems, it is important to consider factors influencing the human use of freshwater resources. We investigated the influence of the landscape position, as well as lake area, recreational facilities, and distance to highways and urban centres, on lake use by boaters in the Northern Highland Lake District of Wisconsin, U.S.A. 2. In aerial surveys of ninety-nine randomly selected lakes, we did not see boats on over half of the lakes. Of the lakes with boats, we found a strong correlation between the number of boats and lake area. Recreational boats tended to be found on large, accessible lakes with good boating facilities. Boats were not seen on small, stained lakes with few recreational facilities. 3. Regression models showed that lake size and landscape position explained 63% of the variability in the average number of boats per lake and landscape position explained 24% of the variability in boat density on all ninety-nine lakes. Social variables representing the quality of boating facilities and the perception of good fishing explained 70% of the variability in number of boats per lake and 54% of the variation in boat density on all lakes. A combined model using both physical and social variables increased the explanatory power for both number and density. Lake use by boaters was correlated with landscape position, the quality of fishing and the availability of recreational facilities. When the analysis was restricted to the forty-six lakes where boats were found, only the availability of recreational facilities proved a significant predictor of boat density. 4. Our results suggest that lake choice by recreational boaters may be best predicted by a combination of the location of a lake in a regional hydrologic landscape, and considerations of available facilities and perceptions regarding fishing

A Review of the Implementation of the Embryonic Stem Cell Test (EST)

The EST has been developed as an in vitro screening test for evaluating the potential embryotoxic effects of substances, to allow their classification into three major classes: non-embryotoxic; weakly embryotoxic; and strongly embryotoxic). It is biologically based on the assumption that chemicals with an embryotoxic potential will block the spontaneous development of embryonic stem cells into beating cardiac muscle cells within the first 10 days of embryonic development . In 2002, the assay was endorsed by the ECVAM Scientific Advisory Committee (ESAC) as scientifically validated and ready to be considered for regulatory acceptance and application. the workshop has reviewed the post validated status of the EST so far.JRC.DDG.I.3-In-vitro method