Lithologic mapping of silicate rocks using TIMS

Common rock-forming minerals have thermal infrared spectral features that are measured in the laboratory to infer composition. An airborne Daedalus scanner (TIMS) that collects six channels of thermal infrared radiance data (8 to 12 microns), may be used to measure these same features for rock identification. Previously, false-color composite pictures made from channels 1, 3, and 5 and emittance spectra for small areas on these images were used to make lithologic maps. Central wavelength, standard deviation, and amplitude of normal curves regressed on the emittance spectra are related to compositional information for crystalline igneous silicate rocks. As expected, the central wavelength varies systematically with silica content and with modal quartz content. Standard deviation is less sensitive to compositional changes, but large values may result from mixed admixture of vegetation. Compression of the six TIMS channels to three image channels made from the regressed parameters may be effective in improving geologic mapping from TIMS data, and these synthetic images may form a basis for the remote assessment of rock composition

Geologic utility of improved orbital measurements

From a geologists point of view, the most important use of orbital cameras is probably to provide spatial or context information in remote areas. This information can be extracted even from broad-band, single channel images provided that the spatial resolution is adequate for the problem at hand. Topographic information, usually provided by stereoscopic images, is next in importance. Any satellite system designed to satisfy general geologic requirements must produce stereo images, preferably with large base/height ratios of 0.5 or more. Satellite coverage at different illumination geometries could provide low Sun angles for regions of low relief where topography must be accentuated, and high Sun angles for areas of high relief or when multispectral data are being collected. Thus a different polar orbit than that of LANDSAT would be advantageous. The extended spectral sensitivity of scanner permits interferences of the composition of rocks in the scene to be drawn directly, rather than from contextual clues

The area around the Orion Nebula observed in the CO (J = 1- 0) transition

An area 1 deg2 around the Orion Nebula has been surveyed with a 2.6 km s-1 wide single-channel receiver. The map shows considerable structure in the east including a bright spot 24' (2.8 pc) from the main CO peak

A unique facility for V/STOL aircraft hover testing

The Langley Impact Dynamics Research Facility (IDRF) was modified to obtain static force and moment data and to allow assessment of aircraft handling qualities during dynamic tethered hover flight. Test probe procedures were also established. Static lift and control measurements obtained are presented along with results of limited dynamic tethered hover flight

Internal thermal noise in the LIGO test masses : a direct approach

The internal thermal noise in LIGO's test masses is analyzed by a new technique, a direct application of the Fluctuation-Dissipation Theorem to LIGO's readout observable, $x(t)=$(longitudinal position of test-mass face, weighted by laser beam's Gaussian profile). Previous analyses, which relied on a normal-mode decomposition of the test-mass motion, were valid only if the dissipation is uniformally distributed over the test-mass interior, and they converged reliably to a final answer only when the beam size was a non-negligible fraction of the test-mass cross section. This paper's direct analysis, by contrast, can handle inhomogeneous dissipation and arbitrary beam sizes. In the domain of validity of the previous analysis, the two methods give the same answer for $S_x(f)$, the spectral density of thermal noise, to within expected accuracy. The new analysis predicts that thermal noise due to dissipation concentrated in the test mass's front face (e.g. due to mirror coating) scales as $1/r_0^2$, by contrast with homogeneous dissipation, which scales as $1/r_0$ ($r_0$ is the beam radius); so surface dissipation could become significant for small beam sizes.Comment: 6 pages, RevTex, 1 figur

Spider webs, stable isotopes and molecular gut content analysis: Multiple lines of evidence support trophic niche differentiation in a community of Hawaiian spiders

1.Adaptive radiations are typically characterized by niche partitioning among their constituent species. Trophic niche partitioning is particularly important in predatory animals, which rely on limited food resources for survival.2.We test for trophic niche partitioning in an adaptive radiation of Hawaiian Tetragnatha spiders, which have diversified in situ on the Hawaiian Islands. We focus on a community of nine species belonging to two different clades, one web-building and the other actively hunting, which co-occur in wet forest on East Maui. We hypothesize that trophic niches differ significantly both: (a) among species within a clade, indicating food resource partitioning, and (b) between the two clades, corresponding to their differences in foraging strategy.3.To assess niches of the spider species, we measure: (a) web architecture, the structure of the hunting tool, and (b) site choice, the physical placement of the web in the habitat. We then test whether differences in these parameters translate into meaningful differences in trophic niche by measuring (c) stable isotope signatures of carbon and nitrogen in the spiders\u27 tissues, and (d) gut content of spiders based on metabarcoding data.4.We find significant interspecific differences in web architecture and site choice. Importantly, these differences are reflected in stable isotope signatures among the five web-building species, as well as significant isotopic differences between web-builders and active hunters. Gut content data also show interspecific and inter-clade differences. Pairwise overlaps of web architecture between species are positively correlated with overlaps of isotopic signature.5.Our results reveal trophic niche partitioning among species within each clade, as well as between the web-building and actively hunting clades. Based on the correlation between web architecture and stable isotopes, it appears that the isotopic signatures of spiders\u27 tissues are influenced by architectural differences among their webs. Our findings indicate an important link between web structure, microhabitat preference and diet in the Hawaiian Tetragnatha

Enhancement of the stability of genetic switches by overlapping upstream regulatory domains

We study genetic switches formed from pairs of mutually repressing operons. The switch stability is characterised by a well defined lifetime which grows sub-exponentially with the number of copies of the most-expressed transcription factor, in the regime accessible by our numerical simulations. The stability can be markedly enhanced by a suitable choice of overlap between the upstream regulatory domains. Our results suggest that robustness against biochemical noise can provide a selection pressure that drives operons, that regulate each other, together in the course of evolution.Comment: 4 pages, 5 figures, RevTeX

An unusual presentation of actinomycosis in a dairy cow

A first lactation dairy cow (in late gestation) presented with a hard round swelling of the right olecranon and slight lameness. A lateromedial radiograph of the right olecranon had a mottled appearance with indistinct borders. Bone biopsy was performed post calving. Histology showed fibrosis and reactive changes, however this sample was considered too superficial and not representative of the whole lesion. Based on the differential diagnoses treatment was not possible and the cow was culled at the end of her lactation. At slaughter the forelimb was retained for further analysis. Grossly, the olecranon was severely enlarged, irregular with multiple yellow granulomas in the cortex and medulla of the bone. Histology showed multifocal pyogranulomas containing bacteria, Splendore-Hoeppli material and surrounded by remodelled bone and fibrosis. Despite displaying biochemical properties characteristic of Actinomycesspecies this could not be confirmed by partial 16s rRNA sequencing and the organism could not be definitively speciated