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Abstract: Many basement-involved fault-related folds are thought to form by reactivation of pre-existing faults. Although oblique slip is expected on such structures it is often difficult to identify because the underlying faults are blind, paleomagnetic records are ambiguous, and mesoscopic deformation patterns in the associated monoclines are often incompletely exposed or difficult to interpret. This study seeks to establish a relationship between oblique slip on a basement reverse fault and the deformation patterns in the overlying folded rock layers. Using scaled physical models of wet clay overlying a rigid basement, we create a suite of Laramide-style folds over basement faults with variable obliquity. Precise displacements and strains on the surface of the clay are recorded using close-range photogrammetry. We use these measurements to predict deformation patterns that we would expect to find in analogous natural structures. The results of our models show that there are three general strain zones that form in monoclines that form above oblique-slip faults. The upper-hinge region of the monocline is dominated by extension, the lower-hinge region by contraction, and the middle of the fold limb is dominated by shear strains. The boundaries of these three zones, as well as the magnitude of strain in each of the zones vary with the amount of oblique slip and fault throw. Deformation should be dominated by joints and extensional faults in the extensional zone, by contractional faults and cleavage in the contractional zone, and may contain extensional, contractional, or strike-slip faults along with joints and cleavage arranged in Riedel style geometries in the shear strain dominated zone. At fault obliquities above 45° there is significant overlap of the different strain zones and deformation patterns in these regions can consequently be very complex, involving reactivation or overprinting of earlier structures, or the formation of mixed-mode structures. Displacements on the surface of our model monoclines suggest that previous paleomagnetic interpretations of vertical axis rotations on natural monoclines may need to be re-evaluated. Although such rotations increase with increasing fault obliquity, the magnitude of these rotations will vary significantly with position across a monocline. [Copyright &y& Elsevier]

Physical models have been widely used to study geological structures for more than one hundred years. The greatest benefit of physical models is that with proper scaling of model dimensions and materials, researchers can directly observe structural or tectonic processes that take millions of years to occur naturally. Despite this benefit, however, use of physical models is not widespread because their construction and analysis is commonly labor-intensive work that yields largely qualitative information on structural geometry and limited quantitative information on displacement and strain. This paper describes how close-range photogrammetry can be used to obtain quantitative information on the geometry, displacement, and strain patterns in an evolving physical model. The technique is an inexpensive, high-resolution, noninvasive, and efficient method that uses standard commercial software and a digital camera to determine the x, y, z positions of high-contrast markers placed on the model surface. The model geometry at any given time is defined by the positions of all the markers, whereas strain and displacement are obtained by comparing, or tracking, the positions of the markers at different times during an experiment. We present as an example application of the technique, an analysis of scaled physical models of monoclimes that form above basement-involved reverse faults with differing displacement distributions. Using close-range photogrammetry, we are able to link fault displacement and lateral propagation history to unique, evolving, three-dimensional (3-D) geometries and deformation patterns that are unlikely to be revealed by other analysis techniques. [ABSTRACT FROM AUTHOR]

The article focuses on the identification and management of porto-systemic shunts which resulted from cirrhotic liver disease complicated by portal hypertension. The authors discuss the case of a patient with nonalcoholic steatohepatitis who developed an unusual porto-systemic shunt. They conclude that unrecognized portal hypertension and resultant porto-systemic shunts may be identified as vascular masses and lead to catastrophic surgical effects if these are not preoperatively characterized.

The article discusses Pseudocirrhosis which resembles cirrhosis but lacks the histopathological markers of cirrhosis and is also seen in patients going through chemotherapy.

Background: Cirrhotic liver disease commonly is complicated by portal hypertension, and the resultant porto-systemic shunts are an important cause of morbidity and mortality in cirrhotic patients. Identification of these shunts and their management is an important part of the medical care provided to this population.Case: We present the case of a patient with nonalcoholic steatohepatitis or nonalcoholic fatty liver disease and resultant portal hypertension who developed an unusual porto-systemic shunt, which at first was thought to represent a highly vascular gynecologic mass. The splanchnic blood was shunted through a recanalized vein interconnecting the splenic vein with the parametrial venous plexus.Conclusion: Unrecognized portal hypertension and resultant porto-systemic shunts may mask themselves as vascular masses and result in catastrophic surgical outcomes if not fully characterized preoperatively. [ABSTRACT FROM AUTHOR]