Boundary condition of grounding lines prior to collapse, Larsen-B Ice Shelf, Antarctica.

Grounding zones, where ice sheets transition between resting on bedrock to full floatation, help regulate ice flow. Exposure of the sea floor by the 2002 Larsen-B Ice Shelf collapse allowed detailed morphologic mapping and sampling of the embayment sea floor. Marine geophysical data collected in 2006 reveal a large, arcuate, complex grounding zone sediment system at the front of Crane Fjord. Radiocarbon-constrained chronologies from marine sediment cores indicate loss of ice contact with the bed at this site about 12,000 years ago. Previous studies and morphologic mapping of the fjord suggest that the Crane Glacier grounding zone was well within the fjord before 2002 and did not retreat further until after the ice shelf collapse. This implies that the 2002 Larsen-B Ice Shelf collapse likely was a response to surface warming rather than to grounding zone instability, strengthening the idea that surface processes controlled the disintegration of the Larsen Ice Shelf.

The development and validation of a behavior rating scale for blood sampling with children.

This article describes the development of a behavior rating scale, which was designed to measure children's behaviors during a blood sampling procedure. Trained observers were able to reliably use the behavior rating scale while observing children's behaviors during blood sampling in a pediatric hospital. Evidence of the instrument's validity was found in a treatment study. In that experiment, youngsters were prepared for the blood sampling procedures by viewing films. Those watching coping or mastery models before blood sampling evidenced significantly higher adaptive responses on the behavior rating scale than those who watched a control film. The behavior rating scale was also significantly related to a global rating and a self-report measure, but not to a physiologic index of anxiety. In summary, the constructed behavior rating scale appears to be a reliable and valid instrument for assessing children's behavior during blood sampling procedures.