Patterns of larval abundance and early juven~le recru~tment of the sea urchins Strongylocentrotus franciscanus and S p u~p~l r a t u s were examined throughout spring and summer of 1994 and 1995 a t 2 s~t e sIn southern Oregon, USA, lying within the northern reglon of the California Current System. Sea temperature and coastal wind records were used as lnd~cators of local upwelling and relaxation events and combined with a method of aging young sea urchin recruits to link specific settlement events with hydrographic events. In 1994 sea urchin larvae were found in plankton collections from April to July, while in 1995 larvae were found from March to July and occurred in a higher percentage of the collections than in 1994. At the 2 sites, settlement occurred from April to August, was variable between years and sites, but most consistently occurred In June. Larval occurrences in the plankton and settlement events in 1994 and 1995 were associated with water masses between 11 and 12°C. Peak settlement in both years 'ivas associated with warm water rvcnts characterized by a mixed watcr column and northward w~n d stress Settlement rates were 10127 durlng warm events characterized by a s t r a t~f~e d water column and low wlnd stress. Dunng the summer flow regime, onshore transport of larvae may be linked to relaxation events forced by wind from the south and onshore Ekman flow.

Magnetic resonance imaging (MRI) should be a powerful tool for characterization of spinal cord pathology in animal models. We evaluated the utility of medium-field MRI for the longitudinal assessment of progression of spinal cord injury (SCI) in a rat model. Thirteen adult rats were subjected to a 6.25 or 25 g-cm unilateral cervical SCI, and underwent MRI and behavioral tests during a 3-week study period. MRI was also performed post-mortem. Quantification of cord swelling, hypointense and hyperintense signal, and lesion length were the most valuable parameters to determine and were highly correlated to behavioral and histopathological measures. Immediately after injury, MRI showed loss of gray matter-white matter differentiation, presence of scattered hyperintense signal and local hypointense signal, and cord swelling in both groups. At 7 days after injury, the spinal cord in the 25 g-cm group was significantly larger than that of the 6.25 g-cm group (p = 0.02). Contrast enhancement of the lesion was seen at 24 h in the 6.25 g-cm group, and at 24 h and 7 days in the 25 g-cm group. The volume of hypointense signal, representing hemorrhage, throughout the lesion region was significantly larger in the 25 g-cm compared to the 6.25 g-cm group at both 14 and 21 days after SCI (p,