Grazing and fire and are major forces shaping patterns of native and exotic species diversity in many grasslands, yet both of these disturbances have notoriously variable effects. Few studies have examined how landscape-level heterogeneity in grassland characteristics, such as soil-based variation in biomass and species composition, may contribute to variation in the effects of fire or grazing....

PURPOSE To describe the characteristic CT, MR, and angiographic features of giant serpentine aneurysms and discuss their endovascular treatment. METHODS Thirteen patients with giant serpentine aneurysms were studied at our institution in the last 3 years. They all underwent CT and MR studies as well as cerebral angiography. More recently, some of the patients were studied with MR angiography....

BACKGROUND AND AIMS Serpentine soils provide a highly selective substrate for plant colonization and growth and represent an ideal system for studying the evolution of plant-ecotypes. In the present study the aim was to identify the genetic architecture of morphological traits distinguishing serpentine and non-serpentine ecotypes of Silene vulgaris. METHODS Using an F(2) mapping population de...

Abstract. The OH stretching vibrational properties of eight serpentine samples from veins the New Caledonian ophiolite have been investigated by Fourier-transform infrared spectroscopy (FTIR) in mid-infrared and near-infrared ranges Raman spectroscopy. were selected for their monophasic composition (Lz: lizardite; Ctl: chrysotile; Atg: antigorite) making them representative three species. Compa...

ultramafic rocks are essentially constituted by silicates of magnesium: forsterite, and/or diopside-enstatite; who’s the most common hydrothermal alteration are the serpentinization. to bou azzer, the serpentinisation affected almost all of the ultrabasic rocks. among the phenomena bound to the serpentinisation observed on the ground, we distinguish the magnesium deposits (carbonated serpentini...

In previous studies’-3 it was observed that the thioglycollate, peroxidase, neutral red, and serpentine cord tests were useful for group differentiation of M. tuberculosis, atypical acid-fast bacilli, and saprophytic mycobacteria. The present investigation was undertaken to determine further the differential potential of these procedures, and to ascertain whether the niacin test4’5 could also b...

The shock equation of state of serpentine has been determined to 150 GPa. Four distinct regions occur along the Hugoniot: a low-pressure phase, a mixed phase region, a high-pressure phase, and a very high pressure phase. The low-pressure phase (LPP) exists under shock pressures to about 40 GPa. This material exhibits shock properties that are partially consistent with those of low pressure serp...

Serpentine soils represent stressful habitats where plants have to cope with heavy metals, moisture limitation and low nutrient availability. We propose that facilitation is an important mechanism structuring plant communities under such stressful conditions. Facilitation has been shown to generate the spatial association of species, forming discrete vegetation patches of phylogenetically dista...