534 research outputs found
Paper Session I-A - DOD Research and Development
Current and proposed DoD programs require a broader on-orbit space test support capability and the availability of space based assets to support non-space, ground or sea based RDT&E and OT&E programs. These programs include Strategic Defense Initiative Organization, National Aeronautics and Space Administration (NASA), Army, Navy, and Air Force systems existing, planned, or being developed. The proliferation of these systems brings about new problems and concerns for safety. They increase the number of on-orbit objects and increase the complexity of coordinating and integrating missions with a resulting increase in potential hazards to operational and R&D space systems. Future testing requirements will require better control of debris and spent vehicles reentering the atmosphere to avoid additional risk to people and property on the earth\u27s surface. Laser and beam systems in space will introduce new challenges for developing well-established and documented procedures for minimizing any safety risks.
With the concern for safety, the high cost of world-wide testing of space systems makes it imperative that more efficient use be made of existing and new test resources. A central coordinating agency is required to schedule and integrate use of increasingly complex multi-range support to avoid duplication of test support resources among the existing DoD ranges and satellite control systems
Southern pine beetle infestation probability mapping using weights of evidence analysis
Weights of Evidence (WofE) spatial analysis was used to predict probability of southern pine beetle (Dendroctonus frontalis) (SPB) infestation in Angelina, Nacogdoches, San Augustine and Shelby Co., TX. Thematic data derived from Landsat imagery (1974–2002 Landsat 1–7) were used. Data layers included: forest covertype, forest age, forest patch size and percent slope. WofE predicted infestation probabilities were signifi cantly higher at infestation locations, versus random locations (p\u3c0.0001). Signifi cantly more infestations occurred in the higher probability areas (p=0.002). Infestation size was not signifi cantly correlated with probability (p=0.0528). Correlations were found between WofE probability and traditional SPB hazard rating, calculated from forest inventory data, using the Mason (1981) system (p\u3c0.0001). WofE probability maps were used to produce current SPB three and fi ve-class hazard rating maps for the study area. WofE was effective for predicting SPB hazard, utilizing existing, remotely-sensed data sets
New records of biting and predaceous midges from Florida, including species new to the fauna of the United States (Diptera: Ceratopogonidae)
We provide new records of biting and predaceous midges (Diptera: Ceratopogonidae) from Florida, including the first documented United States records of Atrichopogon (Atrichopogon) caribbeanus Ewen, Dasyhelea griseola Wirth, D. scissurae Macfie, and Brachypogon (Brachypogon) woodruffi Spinelli and Grogan. Atrichopogon (Meloehelea) downesi Wirth, Forcipomyia (Thyridomyia) monilicornis (Coquillett), F. (T.) nodosa Saunders, Ceratoculicoides blantoni Wirth and Ratanaworabhan, Mallochohelea albibasis (Malloch), Bezzia (Bezzia) imbifida Dow and Turner and B. (B.) mallochi Wirth are recorded for the first time from Florida. Forcipomyia (Thyridomyia) johannseni Thomsen, Bezzia (Bezzia) expolita (Coquillett), and B. (B.) pulverea (Coquillett) are deleted from the ceratopogonid fauna of Florida. Dasyhelea koenigi Delécolle and Rieb is a junior objective synonym of Dasyhelea scissurae Macfie (NEW SYNONYM). The total number of Ceratopogonidae recorded from Florida is now 249 species contained within 27 genera
Current Brazilian forest management guidelines are unsustainable for Swietenia, Cedrela, Amburana, and Copaifera: A response to da Cunha and colleagues
Multitemporal Analysis Using Landsat Thematic Mapper (TM) Bands for Forest Cover Classification in East Texas
Land cover maps have been produced using satellite imagery to monitor forest resources since the launch of Landsat 1. Research has shown that stacking leaf-on and leaf-off imagery (combining two separate images into one image for processing) may improve classification accuracy. It is assumed that the combination of data will aid in differentiation between forest types. In this study we explored potential benefits of using multidate imagery versus single-date imagery for operational forest cover classification as part of an annual remote sensing forest inventory system. Landsat Thematic Mapper (TM) imagery was used to classify land cover into four classes. Six band combinations were tested to determine differences in classification accuracy and if any were significant enough to justify the extra cost and increased difficulty of image acquisition. The effects of inclusion/exclusion of the moisture band (TM band 5) also were examined. Results show overall accuracy ranged from 72 to 79% with no significant difference between single and multidate classifications. We feel the minimal increase (3.06%) in overall accuracy, coupled with the operational difficulties of obtaining multiple (two), useable images per year, does not support the use of multidate stacked imagery. Additional research should focus on fully utilizing data from a single scene by improving classification methodologies
Long-distance dispersal helps germinating mahogany seedlings escape defoliation by a specialist caterpillar
Herbivores and pathogens with acute host specificity may promote high tree diversity in tropical forests by causing distance- and density-dependent mortality of seedlings, but evidence is scarce. Although Lepidoptera larvae are the most abundant and host-specific guild of herbivores in these forests, their impact upon seedling distributions remains largely unknown. A firm test of the mechanism underpinning the Janzen-Connell hypothesis is difficult, even for a single tree species, because it requires more than just manipulating seeds and seedlings and recording their fates. Experimental tests require: (1) an insect herbivore that is identified and highly specialised, (2) linkage to an in situ measure (or prevention) of herbivory, and (3) evaluation and confirmation among many conspecific adult trees across years. Here we present experimental evidence for a spatially explicit interaction between newly germinating seedlings of a Neotropical emergent tree, big-leaf mahogany (Swietenia macrophylla, Meliaceae), and caterpillars of a noctuid moth (Steniscadia poliophaea). In the understory of a southeastern Amazon forest, the proportion of attacks, leaf area lost, and seedling mortality due to this specialised herbivore peaked near Swietenia trees, but declined significantly with increasing distance from mature fruiting trees, as predicted by the Janzen-Connell hypothesis. We conclude that long-distance dispersal events (>50m) provided an early survival advantage for Swietenia seedlings, and propose that the role of larval Lepidoptera as Janzen-Connell vectors may be underappreciated in tropical forest
Hemoprotein Catalyzed Oxygenations: P450s, UPOs and Progress Towards Scalable Reactions
The selective oxygenation of non-activated carbon atoms is an ongoing synthetic challenge and biocatalysts, particularly hemoprotein oxygenases, continue to be investigated for their potential, given both their sustainable chemistry credentials and also their superior selectivity. However, issues of stability, activity and complex reaction requirements often render these biocatalytic oxygenations problematic with respect to scalable industrial processes. A continuing focus on Cyto-chromes P450 (P450s), which require a reduced nicotinamide cofactor and redox protein partners for electron transport, has now led to better catalysts and processes with a greater understanding of process requirements and limitations for both in vitro and whole-cell systems. However, the discovery and development of unspecific peroxygenases (UPOs) has also recently provided valuable complementary technology to P450-catalyzed reactions. UPOs need only hydrogen peroxide to effect ox-ygenations but are hampered by their sensitivity to peroxide and also by limited selectivity. In this perspective we survey recent developments in the engineering of proteins, cells and processes for oxygenations by these two groups of hemopro-teins and evaluate their potential and relative merits for scalable reactions
Visual histological grading system for the evaluation of in vitro-generated neocartilage
Here we present the development of a visual evaluation system for routine assessment of in vitro-engineered cartilaginous tissue. Neocartilage was produced by culturing human articular chondrocytes in pellet culture systems or in a scaffold-free bioreactor system. All engineered tissues were embedded in paraffin and were sectioned and stained with Safranin O-fast green. The evaluation of each sample was broken into 3 categories (uniformity and intensity of Safranin O stain, distance between cells/amount of matrix produced, and cell morphology), and each category had 4 components with a score ranging from 0 to 3. Three observers evaluated each sample, and the new system was independently tested against an objective computer-based histomorphometry system. Pellets were also assessed biochemically for glycosaminoglycan (GAG) content. Pellet histology scores correlated significantly with GAG contents and were in agreement with the computer-based histomorphometry system. This system allows a valid and rapid assessment of in vitro-generated cartilaginous tissue that has a relevant association with objective parameters indicative of cartilage quality
Biocatalytic Synthesis of Moclobemide Using the Amide Bond Synthetase McbA Coupled with an ATP Recycling System
The biocatalytic synthesis of amides from carboxylic acids and primary amines in aqueous media can be achieved using the ATP-dependent amide bond synthetase McbA, via an adenylate intermediate, using only 1.5 equivalents of the amine nucleophile. Following earlier studies that characterized the broad carboxylic acid specificity of McbA, we now show that, in addition to the natural amine substrate 2-phenylethylamine, a range of simple aliphatic amines, including methylamine, butylamine and hexylamine and propargylamine are coupled efficiently to the native carboxylic acid substrate 1-acetyl-9H-β-carboline-3-carboxylic acid by the enzyme, to give amide products with up to >99% conversion. The structure of wild-type McbA in its ami-dation conformation, coupled with modeling and mutational studies, reveal an amide access tunnel and a possible role for residue D201 in amide activation. Amide couplings were slower with anilines and alicyclic secondary amines such as pyrrolidine and piper-idine. The broader substrate specificity of McbA was exploited in the synthesis of the monoamine oxidase A inhibitor moclobe-mide, through the reaction of 4-chlorobenzoic acid with 1.5 equivalents of 4-(2-aminoethyl)morpholine, and utilizing polyphos-phate kinases SmPPK and AjPPK in the presence of polyphosphoric acid and 0.1 equivalents of ATP, required for recycling of the cofactor
Reduction of Murine Cutaneous UVB-Induced Tumor-Infiltrating T Lymphocytes by Dietary Canthaxanthin
The effect of dietary canthaxanthin, retinyl palmitate, or their combination on the tumor-infiltrating T-lymphocyte response (T-TIL) in de novo murine ultraviolet type B irradiation-induced tumors was investigated to elucidate potential mechanisms of action of these compounds. We found that dietary canthaxanthin greatly reduced the number of tumor-infiltrating helper/inducer, suppressor/cytotoxic, and interleukin-2 receptor-positive T lymphocytes and also observed a concomitant statistically significant increase in tumour incidence in canthaxanthin-fed animals. The addition of retinyl palmitate to the canthaxanthin diet ameliorated this negative effect on TIL and the development of skin tumors. We conclude that dietary retinyl palmitate and canthaxanthin can modulate the host T-cell immune response within a growing tumor and may affect tumorigenicity
- …