Many processes in seismic data analysis and seismic imaging can be identified with solution operators of evolution equations. These include data downward continuation and velocity continuation. We have addressed the question of whether isochrons defined by imaging operators can be identified with wavefronts of solutions to an evolution equation. Rays associated with this equation then would pro...

Phytoplankton requires light for photosynthesis, but most phytoplankton species are heavier than water and sink. How can these sinking species persist? Here we show, by means of an advection-di usion-reaction equation of light-limited phytoplankton, that the answer lies in the turbulent motion of water that re-disperses phytoplankton over the vertical water column. More speci cally, we show tha...

A major fraction of particulate organic carbon (POC) in the deep ocean remains molecularly uncharacterized. In an effort to determine the chemical characteristics and source(s) of sinking POC, we studied a nonhydrolyzable fraction of sinking POC using C NMR (nuclear magnetic resonance) spectroscopy and analytical pyrolysis. C NMR spectra and products from analytical pyrolysis of the nonhydrolyz...

BACKGROUND The syndrome of the sinking skin flap (SSSF) with delayed sensorimotor deficits after craniectomy is not well known and often neglected. Among various postulated causes, there is evidence that disturbed brain perfusion may be related to the observed symptoms, and that cranioplasty reliably alleviates these symptoms. We report a case of sinking skin flap syndrome (SSFS) with recovery ...

The Costa Rica Dome is a picophytoplankton-dominated, open-ocean upwelling system in the Eastern Tropical Pacific that overlies the ocean's largest oxygen minimum zone. To investigate the efficiency of the biological pump in this unique area, we used shallow (90-150 m) drifting sediment traps and 234Th:238U deficiency measurements to determine export fluxes of carbon, nitrogen and phosphorus in...

As a transportation hub connecting sea and land, the seismic safety of an undersea tunnel is very important. Based on structural stress characteristics shield tunnel, response analysis coastal nuclear power plant under complex foundation carried out in this paper. Firstly, adopting lateral longitudinal displacement methods, authors study variation distribution features rate diameter change join...

Export of Particulate Organic Carbon (POC) is mainly driven by gravitational sinking. Thus, traditionally, it thought that larger, faster-sinking particles make up most the POC export flux. H...