Global variations in the geoid/topography admittance of venus

Global representations of geoid height and topography are used to map variations in the geoid/topography ratio (admittance) of Venus. The admittance values are permissive of two mutually exclusive models for convection-driven topography. In the first, compressive highland plateaus are expressions of present mantle downwelling, broad volcanic rises are expressions of mantle upwelling, and lowlands overlie regions with no substantial vertical motion in the mantle. In the second, compressive highland plateaus are remnants of an earlier regime of high crustal strain, and most other long-wavelength topographic variations arise from normal convective tractions at the base of the lithosphere.     

TWO-DIMENSIONAL REAL-TIME OCULAR ULTRASONOGRAPHY IN THE DOG

Two-dimensional real-time ultrasonography was performed with three different methods to determine the optimal technique for scanning canine orbital soft tissues. The three techniques included positioning the transducer on the clipped closed eyelid (eyelid contact method), directly on the cornea (corneal contact method), or on a small waterfilled balloon in direct contact with the cornea (water bath offset method). Horizontal and vertical images from the three techniques were compared and graded for diagnostic quality. The corneal contact method provided superior anatomic definition of the posterior globe and extraorbital tissues, whereas the water bath method gave higher-quality images of the anterior chamber and lens. Use of the eyelid contact method to image the eye and periorbital structures was not recommended because of multiple artifacts that severely degrade the image.