Development of bio-optical algorithms to estimate chlorophyll in the Great Salt Lake and New England lakes using in situ hyperspectral measurements

Chlorophyll is widely used to evaluate lake water quality, effectively integrating the chemical, physical and biological state of a lake. Assessment of chlorophyll conditions in lakes can be greatly enhanced by the use of remote sensing, allowing information to be gathered at spatial and temporal scales not possible with traditional limnological sampling methods. In order for remote sensing methods to provide accurate estimates of chlorophyll concentration, algorithms need to be developed with high-quality spectral data paired with water quality measurements and optimized for regional lake differences. In this study, in situ hyperspectral optical measurements were used to develop algorithms to estimate chlorophyll for the Great Salt Lake and New England lakes. The spectral data were used to mimic bands utilized by the MODIS, MERIS, and SeaWiFS sensors, as well as for a theoretical hyperspectral sensor with 3-nm wide bands, providing the capability to evaluate algorithm performance in all of these sensors. In addition to the traditional bands used in these algorithms, alternate band combinations were examined for both ocean color chlorophyll (OC) and maximum chlorophyll index (MCI) algorithms. A simulated 709 nm band was created for MODIS using the 754 nm band, providing a method for testing MODIS with algorithms relying on the key 705 nm to 715 nm wavelength range. In New England lakes, the most effective algorithm for hyperspectral bands (RMS = 0.206, in log decades) and MERIS (RMS = 0.218) was a version of MCI. For MODIS and SeaWiFS, the most effective algorithm used an OC approach with 489 nm as the blue band, yielding an RMS of 0.242 and 0.231, respectively. In the Great Salt Lake, the most effective algorithms for hyperspectral bands and MERIS were based on a single ratio of 709 nm / 675 nm, providing an RMS of 0.236 and 0.249, respectively. For MODIS and SeaWiFS, the most effective algorithm was the OC method using 489 nm as the blue band, which resulted in an RMS of 0.246 and 0.255, respectively

Thermal expansion and elastic anisotropy in single crystal Al2O3 and SiC reinforcements

In single crystal form, SiC and Al2O3 are attractive reinforcing components for high temperature composites. In this study, the axial coefficients of thermal expansion and single crystal elastic constants of SiC and Al2O3 were used to determine their coefficients of thermal expansion and Young's moduli as a function of crystallographic orientation and temperature. SiC and Al2O3 exhibit a strong variation of Young's modulus with orientation; however, their moduli and anisotropies are weak functions of temperature below 1000 C. The coefficients of thermal expansion exhibit significant temperature dependence, and that of the non-cubic Al2O3 is also a function of crystallographic orientation

Spacecraft System Design for an Advanced X-Ray Monitor (AXM) Mission

This paper describes a system concept for a NASA Small Explorer Mission to develop an all-skyviewing Advanced X-ray Monitor (AXM). The spacecraft is configured to be launched from a Pegasus XL vehicle. AXM is designed to provide unprecedented sensitivity to cosmic explosions seen in X-rays. These include the ejections of relativistic jets by black holes in the Galaxy, and the fireballs of gamma ray bursts that originate in distant Galaxies. Such events are captured with 31 cameras mounted on the AXM spacecraft to continuously view 97% of the celestial sphere, excluding occultations by the Earth. The camera detectors are Gas Electron Multiplier (GEM) devices, developed at CERN and used with coded masks for X-ray astronomy. The pointing orientations for the cameras presented a challenge to provide 4p steradian viewing, while accommodating spacecraft subsystems and deployable solar arrays for power. The mounting orientation resembles the 32 faces and vertices of a soccer ball, with one camera eliminated to avoid the saturating effect of solar X-rays. The objective of continuous, all-sky viewing is accomplished with a three-axis stabilized attitude control subsystem with the solar panels pointed close to the Sun. The AXM mission is designed for launch into a ~600-km altitude, circular, equatorial orbit. An approximately 1 degree spacecraft maneuver once per day will maintain the solar panels aligned with the Sun. The spacecraft is powered by solar arrays that deploy after launch and are then fixed for the mission duration. Within limitations, the AXM spacecraft has been designed to gracefully tolerate many kinds of anomalies

Analysis of the putative role of CR1 in Alzheimer’s disease: Genetic association, expression and function

Chronic activation of the complement system and induced inflammation are associated with neuropathology in Alzheimer's disease (AD). Recent large genome wide association studies (GWAS) have identified single nucleotide polymorphisms (SNPs) in the C3b/C4b receptor (CR1 or CD35) that are associated with late onset AD. Here, anti-CR1 antibodies (Abs) directed against different epitopes of the receptor, were used to localize CR1 in brain, and relative binding affinities of the CR1 ligands, C1q and C3b, were assessed by ELISA. Most Abs tested stained red blood cells in blood vessels but showed no staining in brain parenchyma. However, two monoclonal anti-CR1 Abs labeled astrocytes in all of the cases tested, and this reactivity was preabsorbed by purified recombinant human CR1. Human brain-derived astrocyte cultures were also reactive with both mAbs. The amount of astrocyte staining varied among the samples, but no consistent difference was conferred by diagnosis or the GWAS-identified SNPs rs4844609 or rs6656401. Plasma levels of soluble CR1 did not correlate with diagnosis but a slight increase was observed with rs4844609 and rs6656401 SNP. There was also a modest but statistically significant increase in relative binding activity of C1q to CR1 with the rs4844609 SNP compared to CR1 without the SNP, and of C3b to CR1 in the CR1 genotypes containing the rs6656401 SNP (also associated with the larger isoform of CR1) regardless of clinical diagnosis. These results suggest that it is unlikely that astrocyte CR1 expression levels or C1q or C3b binding activity are the cause of the GWAS identified association of CR1 variants with AD. Further careful functional studies are needed to determine if the variant-dictated number of CR1 expressed on red blood cells contributes to the role of this receptor in the progression of AD, or if another mechanism is involved

Logistic support provided to Australian disaster medical assistance teams: results of a national survey of team members

Background: It is likely that calls for disaster medical assistance teams (DMATs) continue in response to international disasters. As part of a national survey, the present study was designed to evaluate the Australian DMAT experience and the need for logistic support.\ud \ud Methods: Data were collected via an anonymous mailed survey distributed via State and Territory representatives on the Australian Health Protection Committee, who identified team members associated with Australian DMAT deployments from the 2004 Asian Tsunami disaster.\ud \ud Results: The response rate for this survey was 50% (59/118). Most of the personnel had deployed to the South East Asian Tsunami affected areas. The DMAT members had significant clinical and international experience. There was unanimous support for dedicated logistic support with 80% (47/59) strongly agreeing. Only one respondent (2%) disagreed with teams being self sufficient for a minimum of 72 hours. Most felt that transport around the site was not a problem (59%; 35/59), however, 34% (20/59) felt that transport to the site itself was problematic. Only 37% (22/59) felt that pre-deployment information was accurate. Communication with local health providers and other agencies was felt to be adequate by 53% (31/59) and 47% (28/59) respectively, while only 28% (17/59) felt that documentation methods were easy to use and reliable. Less than half (47%; 28/59) felt that equipment could be moved easily between areas by team members and 37% (22/59) that packaging enabled materials to be found easily. The maximum safe container weight was felt to be between 20 and 40 kg by 58% (34/59).\ud \ud Conclusions: This study emphasises the importance of dedicated logistic support for DMAT and the need for teams to be self sufficient for a minimum period of 72 hours. There is a need for accurate pre deployment information to guide resource prioritisation with clearly labelled pre packaging to assist access on site. Container weights should be restricted to between 20 and 40 kg, which would assist transport around the site, while transport to the site was seen as problematic. There was also support for training of all team members in use of basic equipment such as communications equipment, tents and shelters and water purification systems

A new milliped of the genus Colactis from Mexico (Chordeumida, Lysiopetalidae). American Museum novitates ; no. 1673

4 p. : ill. ; 24 cm.Includes 1 bibliographical reference (p. [1])

International Engineering Foundation Conference on the Plastic Deformation of Ceramics

This proceedings volume, "Plastic Deformation of Ceramics," constitutes the papers of an international symposium held at Snowbird, Utah from August 7-12, 1994. It was attended by nearly 100 scientists and engineers from more than a dozen countries representing academia, national laboratories, and industry. Two previous conferences on this topic were held at The Pennsylvania State University in 1974 and 1983. Therefore, the last major international conference focusing on the deformation of ceramic materials was held more than a decade ago. Since the early 1980s, ceramic materials have progressed through an evolutionary period of development and advancement. They are now under consideration for applications in engineering structures. The contents of the previous conferences indicate that considerable effort was directed towards a basic understanding of deformation processes in covalently bonded or simple oxide ceramics. However, now, more than a decade later, the focus has completely shifted. In particular, the drive for more efficient heat engines has resulted in the development of silicon-based ceramics and composite ceramics. The discovery of high-temperature cupric oxide-based superconductors has created a plethora of interesting perovskite-Iike structured ceramics. Additionally, nanophase ceramics, ceramic thin films, and various forms of toughened ceramics have potential applications and, hence, their deformation has been investigated. Finally, new and exciting areas of research have attracted interest since 1983, including fatigue, nanoindentation techniques, and superplasticity