The Great Filter refers to a highly speculative theory that implicitly claims one can test, via a probability model, whether known aspects of the history of life on Earth are consistent with the hypothesis that emergence of intelligent life was very unlikely. We describe the theory and some of the many objections to it. We give a mathematical argument to show that one objection, namely that it ...

Cellulose is one of the most abundant non-degradable organic compound on earth. Near about half of the municipal and agricultural solid wastes contain cellulose or their derivatives. Saccharification or enzymatic hydrolysis of cellulosic wastes liberates glucose. In the present work, cellulase from Cellulomonas uda was extracted, partially purified by dialysis and immobilized on an organic supp...

The emergence of multi-cellular organs and their organization into complex body plans is a major cornerstone concerning origin of life on Earth. This requires that the fundamental unit of life, namely the cell, must communicate, coordinate and organize. Cell communication mediated by signal transduction pathways is essential for the development and functioning of any organism. About 20 differen...

The compounds BaLn(2)Se(4) (Ln = rare-earth metal = lanthanide = Er, Tm and Yb), namely barium di(erbium/thulium/ytterbium) tetraselenide, crystallize in the orthorhombic space group Pnma in the CaFe(2)O(4) structure type. In this structure type, all atoms possess m symmetry. The Ln atoms are octahedrally coordinated by six Se atoms. A three-dimensional channel structure is formed by the corner...

South African Palabora vermiculite was modified by ion exchange with ammonium and selected alkali metal and alkaline earth metal ions. In the exchanged vermiculite with ammonium ions, it was found that ammonia and water were the blowing agents and they were simultaneously released during thermal degradation. In the increasing ionic potential series: Na, Ba, Ca and Mg, it was found that the onse...

To address a key science research topic for the global water and energy cycle, namely measuring soil moisture under substantial vegetation canopies and to useful depths, we have developed a concept for a synthetic aperture radar (SAR) system operating simultaneously at UHF and VHF frequencies. We are currently prototyping key technology items that enable this concept under the NASA Earth Scienc...

Extraction of landscape features from LiDAR data has been studied widely in the past few years. These feature extraction methodologies have been focussed on certain types of features only, namely the bare earth model, buildings principally containing planar roofs, trees and roads. In this paper, we present a methodology to process LiDAR data through DBSCAN, a density based clustering method, wh...

The availability of high resolution remote sensing satellites, namely LANDSAT and SPOT, and the set up of efficient data delivery facilities, have enabled us to acquire and update large image data bases from any part of the earth. More over, the geometric properties of the CCD cameras shipped in those satellites allow cartographic data to be produced. ISTAR, as several other companies in the wo...

The extraction of gravity anomalies from airborne strapdown INS gravimetry has been mainly based on state-space approach (SSA), which has many advantages but displays a serious disadvantage, namely, its very limited capacity to handle space correlations (like the rigorous treatment of cross-over points). This paper examines an alternative through the well known geodetic approach, where the INS ...

It is interesting to contemplate an entangled bank, clothed with many plants of many kinds, with birds singing on the bushes, with various insects flitting about, and with worms crawling through the damp earth, and to reflect that these elaborately constructed forms, so different from each other, and dependent on each other in so complex a manner, have all been produced by laws acting around us...