Notes on Amandinea Petermannii Comb.nov. (Physciaceae) from Antarctica

The new combination Amandinea petermannii (Hue) Matzer, Mayrh. & Scheidegger; is proposed. The taxonomy, morphology, anatomy, chemistry, ecology and distribution of this lichen are discussed. Rinodina convoluta D. C. Lindsay is synonym of A. petermanni

Complex Fluids and Hydraulic Fracturing

Nearly 70 years old, hydraulic fracturing is a core technique for stimulating hydrocarbon production in a majority of oil and gas reservoirs. Complex fluids are implemented in nearly every step of the fracturing process, most significantly to generate and sustain fractures and transport and distribute proppant particles during and following fluid injection. An extremely wide range of complex fluids are used: naturally occurring polysaccharide and synthetic polymer solutions, aqueous physical and chemical gels, organic gels, micellar surfactant solutions, emulsions, and foams. These fluids are loaded over a wide range of concentrations with particles of varying sizes and aspect ratios and are subjected to extreme mechanical and environmental conditions. We describe the settings of hydraulic fracturing (framed by geology), fracturing mechanics and physics, and the critical role that non-Newtonian fluid dynamics and complex fluids play in the hydraulic fracturing process

Numerical Modeling of Fluid Flow in Solid Tumors

A mathematical model of interstitial fluid flow is developed, based on the application of the governing equations for fluid flow, i.e., the conservation laws for mass and momentum, to physiological systems containing solid tumors. The discretized form of the governing equations, with appropriate boundary conditions, is developed for a predefined tumor geometry. The interstitial fluid pressure and velocity are calculated using a numerical method, element based finite volume. Simulations of interstitial fluid transport in a homogeneous solid tumor demonstrate that, in a uniformly perfused tumor, i.e., one with no necrotic region, because of the interstitial pressure distribution, the distribution of drug particles is non-uniform. Pressure distribution for different values of necrotic radii is examined and two new parameters, the critical tumor radius and critical necrotic radius, are defined. Simulation results show that: 1) tumor radii have a critical size. Below this size, the maximum interstitial fluid pressure is less than what is generally considered to be effective pressure (a parameter determined by vascular pressure, plasma osmotic pressure, and interstitial osmotic pressure). Above this size, the maximum interstitial fluid pressure is equal to effective pressure. As a consequence, drugs transport to the center of smaller tumors is much easier than transport to the center of a tumor whose radius is greater than the critical tumor radius; 2) there is a critical necrotic radius, below which the interstitial fluid pressure at the tumor center is at its maximum value. If the tumor radius is greater than the critical tumor radius, this maximum pressure is equal to effective pressure. Above this critical necrotic radius, the interstitial fluid pressure at the tumor center is below effective pressure. In specific ranges of these critical sizes, drug amount and therefore therapeutic effects are higher because the opposing force, interstitial fluid pressure, is low in these ranges

II - Le bilan sensori-moteur de l'enfant : éléments théoriques et cliniques

Theoretical advances in the field of child psychology have modified our understanding of developmental processes and have thus brought about the elaboration of new clinical practices. From an instrumental point of view, the sensori-motor approach proposes original contributions for a better understanding of the developing child. This perspective also allows to redefine some aspects of the clinical practices, especially by considering the clinical examination as part of a long term psycho-pedagogic process.Les progrès théoriques réalisés dans le domaine de la psychologie de l'enfant ont transformé notre compréhension du développement et nous ont amené à développer des pratiques cliniques nouvelles. Abordée dans une perspective instrumentale, la sensor i-mo triché offre des propositions originales pour comprendre l'enfant en développement. Cette approche permet également de redéfinir certains aspects de la démarche clinique, notamment en situant l'examen dans un processus psycho-éducatif à long terme.Bullinger André, de Santa Ana I., Grivel P., Millan R., Scheidegger Pascal, Schmid Pons N., Tschopp Ch. II - Le bilan sensori-moteur de l'enfant : éléments théoriques et cliniques. In: Enfance, n°1, 1996. pp. 41-50