Seasat altimeter calibration: initial results

Preliminary analysis of radar altimeter data indicates that the instrument has met its specifications for measuring spacecraft height above the ocean surface (+/- 10 centimeters) and significant wave height (+/- 0.5 meter). There is ample evidence that the radar altimeter, having undergone development through three earth orbit missions [Skylab, Geodynamics Experimental Ocean Satellite 3 (GEOS-3), and Seasat], has reached a level of precision that now makes possible its use for important quantitative oceanographic investigations and practical applications.     

Soil resources: What is needed and how do we maintain these resources

The soil as a resouce in potato production must be maintained if potato production is to be sustained into the 21st century. Increased pest resistance, resource scarcity, and increased input costs will all be important in determining the availability of technology in the future. As demands to maintain and improve environmental quality increase, our ability to overcome poor soil management by increased inputs may be restricted. j To sustain soil as a resource more attention must be given to soil organic matter, structure, and water holding capacity. Cropping systems that increase crop residue returned to the soil and reduce tillage can increase soil organic matter levels and improve soil physical properties. Greenmanure crops may also help reduce pathogen populations. Soil compaction, soil erosion, and salinization represent the most significant threats to maintaining the soil resource. Compaction can significantly limit the soil’s ability to supply water and nutrients to the plant by limiting water holding capacity and root growth. Limiting rooting depth increases the potential for nitrates to be leached below the rooting zone. Erosion, through the removal of the most productive topsoil, has the potential to destroy soil productivity. The actual impact of erosion over time is very difficult to measure and has been compensated for by increased inputs. Salinization throughout history has decreased productivity of irrigated soils. The sustainability of the soil resource depends upon the development and use of Best Management Practices that maintain or improve soil physical properties, while minimizing soil compaction and erosion. These practices will have to be developed within the parameters established by changing human needs and expectations.     

Antioxidant Properties of Chitosan Coatings on Frozen Atlantic Salmon Fillet Portions

Atlantic salmon contain omega-3 fatty acids, which play important roles in promoting human health but are highly susceptible to oxidation. Chitosan has been shown to have antioxidant properties which could be beneficial in extending the shelf life of Atlantic salmon; however, the effects of chitosan molecular size on oxidation of salmon fillets have not been reported. The primary objective of this study was to evaluate the effects of chitosan coatings on lipid oxidation of Atlantic salmon fillet portions during 5 months frozen storage. The effects of chitosan molecular weight (high molecular weight, low molecular weight, and enzymatically degraded chitosan), concentration (0.5 and 1.0%), and the addition of 1% ascorbic acid to the chitosan coating were evaluated. Chitosan molecular weight significantly affected oxidation as evaluated by propanal levels and changes in L* values of the fillet portions. The chitosan treatment with added ascorbic acid resulted in the lowest propanal levels during 5 months of frozen storage. Manipulation of chitosan molecular weight and incorporation of natural antioxidants into chitosan coatings can provide an effective method of reducing lipid oxidation during extended frozen storage of seafood products.     

Incorporating information on bottlenose dolphin distribution into marine protected area design

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Sequencing of Culex quinquefasciatus establishes a platform for mosquito comparative genomics

Culex quinquefasciatus (the southern house mosquito) is an important mosquito vector of viruses such as West Nile virus and St. Louis encephalitis virus, as well as of nematodes that cause lymphatic filariasis. C. quinquefasciatus is one species within the Culex pipiens species complex and can be found throughout tropical and temperate climates of the world. The ability of C. quinquefasciatus to take blood meals from birds, livestock, and humans contributes to its ability to vector pathogens between species. Here, we describe the genomic sequence of C. quinquefasciatus: Its repertoire of 18,883 protein-coding genes is 22% larger than that of Aedes aegypti and 52% larger than that of Anopheles gambiae with multiple gene-family expansions, including olfactory and gustatory receptors, salivary gland genes, and genes associated with xenobiotic detoxification.