We present a simple method for computing angle-domain Common Image Gathers (CIGs) using prestack reverse time migration. The proposed method is an extension of the method proposed by Rickett and Sava (2001) to compute CIGs by downward-continuation shot-profile migration. We demonstrate with a synthetic example the use of the CIG gathers for migration velocity updating. A challenge for imaging b...

We show in this paper how the application of convex duality leads to various reformulations of the classical non optimizable least squares approach to waveform prestack inversion. These reformulations search all for i) a background velocity model and ii) a re-ectivity model deened in the time domain, and linked to the usual depth reeectivity model by prestack depth migration. We show that the d...

Imaging the change in physical parameters in the subsurface requires an estimate of the long wavelength component of the same parameters in order to reconstruct the kinematics of the waves propagating in the subsurface. The model is unknown and must be estimated from the same data. One can try to reconstruct the method by matching the recorded data with modeled waveforms extrapolated in a trial...

PURPOSE To evaluate new physiologic and three-dimensional methods for monitoring leukocyte behavior in mouse retina. METHODS Endotoxin-induced uveitis (EIU) was produced in mice by footpad injection of lipopolysaccharide (LPS). Leukocytes were labeled with acridine orange (AO). Leukocyte rolling in the retinal microcirculation was evaluated in vivo with AO digital fluorography. The number of ...

Wind profiles from an operational C-band Doppler radar have been combined with data from a bird tracking radar to assess the wind profile quality during bird migration. The weather radar wind profiles (WRWPs) are retrieved using the well-known volume velocity processing (VVP) technique. The X-band bird radar performed range–height scans perpendicular to the main migration direction and bird den...

Blood suspension fails to penetrate a capillary with radius R less than 50 microm even if the capillary is perfectly wettable. This invasion threshold is attributed to three red blood cells (RBCs) segregation mechanisms--corner deflection at the entrance, the intermediate deformation-induced radial migration and shear-induced diffusion within a packed slug at the meniscus. The shear-induced rad...

The immune response of C57BL mice to a DBA/2 tumor allograft has been assessed in two assays of cell-mediated immunity, the in vitro lysis of (51)Cr-labeled target cells and the antigen-mediated inhibition of macrophage migration. Both assays were shown to be measuring a T-cell-mediated reaction. Three types of experiments suggested that distinct subpopulations of T cells mediate these reaction...

This paper explores the relationship between velocity uncertainty and AVO-related seismic attributes in a dataset from the Blake Outer Ridge, offshore from Florida and Georgia. From an initial velocity model, several realizations were generated that are perturbations of the original velocity model. Prestack wave-equation migration was applied to the data for each velocity realization. In the mi...

Ground Penetrating Radar is becoming increasingly popular to use as a non-destructive assessment method for investigating reinforced concrete structures. The large amount of data collected take significant level of experience to interpret. Ground Penetrating Radar scans of concrete produce images which are made of arc segments. The shape of each arc is determined by the shape of the object, pos...

Reverse time migration backscattering contains kinematic information that can be used to constrain velocity models. The backscattering results from the correlation between forward scattered and backscattered wavefields from sharp interfaces, i.e., sediment-salt interfaces. The synchronization between these wavefields depends on the velocity of the sediment section and the correct interpretation...