Integration of airborne thematic mapper simulator (TMS) data and digitized aerial photography via an ISH transformation

Abstract

In water sampling it is very common to use human experience to determine sampling locations. We present results from a neural network analysis of multispectral imaging data from the Compact Airborne Spectrographic Imager (casi) to determine significant water sampling locations. In this study Lake Tegel in Berlin, Germany, was overflown on different days. The analysis of the remote sensing data results in a clustering of the overflown water body for each pass. The neural network clusters found for each pass have been related to each other. This procedure enables us to optimize the number and location of water sampling stations.     

Recognizable primary volcanic and sedimentary features in a low-strain domain of the highly deformed, oldest known (≈ 3.7–3.8 Gyr) Greenstone Belt, Isua, West Greenland

A low-strain domain has been identified in the metamorphosed, mostly highly deformed volcanic and sedimentary rocks of the early Archaean Isua supracrustal belt. This domain contains well-preserved volcanic and sedimentary features, including basaltic pillow lavas, pillow breccia, heterogeneous volcanic breccia, amygdules in metabasalt, and polymict conglomerate dominated by recrystallized chert and volcanic clasts. The low-strain domain is bounded by highly deformed rocks mostly derived from basalt, chert, and banded iron formation. These discoveries demonstrate that some primary features have escaped the pervasive metasomatism dominant in other parts of the belt and, furthermore, strengthen the characterization of the Isua supracrustals as a typical greenstone belt.     

Chronology and evolution of the Middle Proterozoic Albany‐Fraser Orogen,Western Australia

Geochemical and Sm‐Nd isotopic data, and 19 ion‐microprobe U‐Pb zircon dates are reported for gneiss and granite from the eastern part of the Albany‐Fraser Orogen. The orogen is dominated by granitic rocks derived from sources containing both Late Archaean and mantle‐derived components. Four major plutonic episodes have been identified at ca 2630 Ma, 1700–1600 Ma, ca 1300 Ma and ca 1160 Ma. Orthogneiss, largely derived from ca 2630 Ma and 1700–1600 Ma granitic precursors, forms a belt along the southeastern margin of the Yilgarn Craton. These rocks, together with gabbro of the Fraser Complex, were intruded by granitic magmas and metamorphosed in the granulite facies at ca 1300 Ma. They were then rapidly uplifted and transported westward along low‐angle thrust faults over the southeastern margin of the Yilgarn Craton. Between ca 1190 and 1130 Ma, granitic magmas were intruded throughout the eastern part of the orogen. These new data are integrated into a review of the geological evolution of the Albany‐Fraser Orogen and adjacent margin of eastern Antarctica, and possibly related rocks in the Musgrave Complex and Gawler Craton.     

Effects of antifouling biocides to the germination and growth of the marine macroalga, Hormosira banksii (Turner) Desicaine

The International Maritime Organisation's (IMO) ban on the use of tributyltin in antifouling paints has inevitability increased the use of old fashioned antifoulants and/or the development of new paints containing 'booster biocides'. These newer paints are intended to be environmentally less harmful, however the broader environmental effects of these 'booster biocides' are poorly known. Germination and growth inhibition tests using the marine macroalga, Hormosira banksii (Turner) Desicaine were conducted to evaluate the toxicity of four new antifouling biocides in relation to tributyltin-oxide (TBTO). Each of the biocides significantly inhibited germination and growth of Hormosira banksii spores. Toxicity was in increasing order: diuron < zineb < seanine 211< zinc pyrithione < TBTO. However, the lack of knowledge on partitioning in the environment makes it difficult to make a full assessment on whether the four biocides tested offer an advantage over organotin paints in terms of environmental impact.     

The Cosmic Lens All-Sky Survey – II. Gravitational lens candidate selection and follow-up

We report the final results of the search for gravitationally lensed flat-spectrum radio sources found in the combination of CLASS (Cosmic Lens All-Sky Survey) and JVAS (Jodrell Bank VLA Astrometric Survey). VLA (Very Large Array) observations of 16 503 sources have been made, resulting in the largest sample of arcsec-scale lens systems available. Contained within the 16 503 sources is a complete sample of 11 685 sources which have two-point spectral indices between 1.4 and 5 GHz flatter than −0.5, and 5-GHz flux densities  ≥30 mJy  . A subset of 8958 sources form a well-defined statistical sample suitable for analysis of the lens statistics. We describe the systematic process by which 149 candidate lensed sources were picked from the statistical sample on the basis of possessing multiple compact components in the 0.2-arcsec resolution VLA maps. Candidates were followed up with 0.05-arcsec resolution MERLIN and 0.003-arcsec VLBA observations at 5 GHz and rejected as lens systems if they failed well-defined surface brightness and/or morphological tests. To illustrate the candidate elimination process, we show examples of sources representative of particular morphologies that have been ruled out by the follow-up observations. 194 additional candidates, not in the well-defined sample, were also followed up. Maps for all the candidates can be found on the World Wide Web at http://www.jb.man.ac.uk/research/gravlens/index.html . We summarize the properties of each of the 22 gravitational lens systems in JVAS/CLASS. 12 are double-image systems, nine are four-image systems and one is a six-image system. 13 constitute a statistically well-defined sample giving a point-source lensing rate of  1:690 ± 190  . The interpretation of the results in terms of the properties of the lensing galaxy population and cosmological parameters will be published elsewhere.     

Chemical Telemetry of OH Observed to Measure Interstellar Magnetic Fields

We present models for the chemistry in gas moving towards the ionization front of an HII region. When it is far from the ionization front, the gas is highly depleted of elements more massive than helium. However, as it approaches the ionization front, ices are destroyed and species formed on the grain surfaces are injected into the gas phase. Photodissociation removes gas phase molecular species as the gas flows towards the ionization front. We identify models for which the OH column densities are comparable to those measured in observations undertaken to study the magnetic fields in star forming regions and give results for the column densities of other species that should be abundant if the observed OH arises through a combination of the liberation of H₂O from surfaces and photodissociation. They include CH₃OH, H₂CO, and H₂S. Observations of these other species may help establish the nature of the OH spatial distribution in the clouds, which is important for the interpretation of the magnetic field results.     

Galaxy evolution: Inhomogeneous halo collapse

In an effort to study the halo globular clusters we perform a simulation of inhomogeneous halo collapse using a SPH/N-body code. We include dark matter particles, (cooling) gas, and stars. Supernova feedback is included as a heat source for the gas in the local environment of star forming regions. We find this model cannot reproduce the age distribution and spatial distribution of halo globular clusters. This revised version was published online in August 2006 with corrections to the Cover Date.