South American non-marine shells : further remarks and descriptions / Fritz Haas.

v.34:no.9(1952)

Some remarkable shells of a South American fresh-water mussel [by] Fritz Haas

v.31:no.3(1945)

On some small collections of inland shells from South America / Fritz Haas.

v.34:no.35(1955)

Remarks on and descriptions of South American non-marine shells.

v.31:no.46(1951)

Non-marine shells from Borneo, collected by the Borneo Zoological expedition, 1950.

v.31:no.52(1951)

On non-marine shells from Northeastern Brazil and Peru.

v.37:no.10(1955)

Type fossil Miscellanea (worms, problematica, conoidal shells, trace fossils) in Field Museum / Gerald Glenn Forney --, Daniel T. Jenkins -- and Matthew H. Nitecki --.

v.37:no.1(1977)

Three new land shells from Peru.

v.31:no.23(1947)

Hyperplasia of elastic tissue in hepatic schistosomal fibrosis

Elastic tissue hyperplasia, revealed by means of histological, immunocytochemical and ultrastructural methods, appeared as a prominent change in surgical liver biopsies taken from 61 patients with schistosomal periportal and septal fibrosis. Such hyperplasia was absent in ecperimental murine schistosomiasis, including mice with "pipe-stem" fibrosis. Displaced connective tissue cells in periportal areas, such as smooth muscle cells, more frequently observed in human material, could be the site of excessive elastin synthesis, and could explain the differences observed in human and experimental materials. Elastic tissue, sometimes represented by its microfibrillar components, also appeared to be more condensed in areas of matrix (collagen) degradation, suggesting a participation of this tissue in the remodelling of the extracellular matrix. By its rectratile properties elastic tissue hyperplasia in hepatic schistosomiasis can cause vascular narrowing and thus play a role in the pathogenesis of portal hypeertension.

An objective anisotropic elastic plastic model and Algorithm applicable to bone mechanics

The implicit projection algorithm of isotropic plasticity is extended to an objective anisotropic elastic perfectly plastic model. The recursion formula developed to project the trial stress on the yield surface, is applicable to any non linear elastic law and any plastic yield function.A curvilinear transverse isotropic model based on a quadratic elastic potential and on Hill's quadratic yield criterion is then developed and implemented in a computer program for bone mechanics perspectives. The paper concludes with a numerical study of a schematic bone-prosthesis system to illustrate the potential of the model.

Permeability estimates from poro-elastic dispersion analyses of sonic logs

Modern sonic logging tools designed for shallow environmental and engineering applications allow for P-wave phase velocity measurements over a wide frequency band. Methodological considerations indicate that, for saturated unconsolidated sediments in the silt to sand range and source frequencies ranging from approximately 1 to 30 kHz, the observable poro-elastic P-wave velocity dispersion is sufficiently pronounced to allow for reliable first-order estimations of the underlying permeability structure. These predictions have been tested on and verified for a surficial alluvial aquifer. Our results indicate that, even without any further calibration, the thus obtained permeability estimates as well as their variabilities within the pertinent lithological units are remarkably close to those expected based on the corresponding granulometric characteristics.