Some minerals as new natural models of ferrites

Summary The electron density distribution in the intermediateE-F layer is determined by developing theN(z) profile into a power series. The unknown coefficients are found by means of the boundary conditions for transition towards theE andF1 layers as well as by the value of the maximum electron density in the intermediate layer. In case that stratiform layers in theE-F layer which can be sounded are not available, the measured value for the nondeviative absorption at short waves reflected by theF layer is made use of. The comparisons show the reliable accuracy of the method when seven terms are used in the power series.     

The use of airborne laser scanning to develop a pixel-based stratification for a verified carbon offset project

Background  

The voluntary carbon market is a new and growing market that is increasingly important to consider in managing forestland. Monitoring, reporting, and verifying carbon stocks and fluxes at a project level is the single largest direct cost of a forest carbon offset project. There are now many methods for estimating forest stocks with high accuracy that use both Airborne Laser Scanning (ALS) and high-resolution optical remote sensing data. However, many of these methods are not appropriate for use under existing carbon offset standards and most have not been field tested.     

Seismically active fracture zones related to the western segment of the hellenic subduction

Summary A system of 12 seismically active fracture zones was delineated on the basis of the distribution of earthquake foci in the continental lithosphere in the western domain of the Hellenic area. The position and width of the outcrop, thickness, dip and maximum depth of the individual fracture zones were estimated and complemented by tectonic and geological evidence. The existence of the fracture zones was confirmed by the occurrence of historical disastrous earthquakes.     

ISOCAM Observations of the Centre of M31

We present ISOCAM images and CVF observations of the centre of the Andromeda Galaxy. The images were taken in the LW1, LW2, LW3 and LW6 filters. They show an elliptical contribution of the stars and the spatial distribution of dust. The dust distribution follows a spiral structure identical to the distribution of absorption at optical wavelengths. The spectrum of the dust as seen from the CVF observations shows only one broad emission band at 11.3 μmwhile other PAH features at 6.2, 7.7 and 8.6 μm are absent or very faint. This seems to correspond to infrared emission of combinations of neutral polycyclic aromatic hydrocarbons. This revised version was published online in July 2006 with corrections to the Cover Date.     

Teachers’ Concepts of Map-Skill Development

Maps are an increasingly used source of information and it is therefore essential to develop map skills in students. A fundamental factor affecting the choice of map skills and the way they are developed is the teacher and his/her concept of map work. Based on the results of a survey and semi-structured interviews among Czech teachers, this study identifies three basic conceptual types of teachers: “Navigators” and “Problem-Oriented” and “Source-Oriented” teachers. Similarities with teachers’ concepts of map-skill development identified in previous studies are discussed together with means of improvement.     

Geochemistry and mineralogy of bentonites from Ishirini (Libya)

Smectites from the Ishirini bentonite deposit (Libya) were analysed for their oxygen and hydrogen isotopic ratios. Based on published isotopic fractionation data, the results indicate a predominantly meteoric origin of the fluids responsible for the transformation of pyroclastic rocks to bentonite at temperatures ranging from 30 to 90 °C. The thermal effect of the subsequent emplacement of volcanic intrusions was further evaluated by a detailed study of δ¹⁸O isotopic composition of smectites and fluid inclusions in quartz separated from silicified rings produced by the thermal action of a basalt dike. Five different groups of fluids were distinguished based on salinity and homogenization temperatures.

The contact zone of bentonite affected by high concentrated saline solution exhibit mineralogical changes. High salinity and high temperature also remarkably influence the technical parameters of bentonites and reduce, for example, the cation exchange capacity (CEC) or microporosity.