Observations on Arctic and Red-throated Loons at Storkersen Point, Alaska

Habitat requirements of arctic loons (Gavia arctica) and red-throated loons (Gavia stellata) were studied at Storkersen Point on the Arctic coastal plain of Alaska from 1971 to 1975. Nest success ranged from 28 to 92 per cent and 33 to 78 per cent for arctic and red-throated loons, respectively. Loons were ecologically isolated in their feeding habits and use of wetlands. Arctic loons fed to their young invertebrates captured in the nest pond, and red-throated loons fed to theirs fish captured from the Beaufort Sea. Both species preferred islands as nest substrates, but arctic loons utilized large ponds with stands of Arctophila fulva wetlands for nesting, whereas, red-throated loons used smaller, partially-drained basins most frequently

The Geomorphology of Teshekpuk Lake in Relation to Coastline Configuration of Alaska's Coastal Plain

Observations on a drained and a partially drained lake basin adjacent to Teshekpuk Lake led to the conclusion that the drainage was a result of erosion produced by the moat-current phenomenon of Teshekpuk Lake. The processes of shoreline erosion and lake-capture seem to be responsible for the growth and configuration of Teshekpuk Lake. Similar phenomena between large lakes and the Beaufort Sea may also have influenced the shoreline configuration of vast coastal areas such as Admiralty Bay, Dease Inlet and Harrison Bay

Identification of Tundra Land Cover near Teshekpuk Lake, Alaska Using SPOT Satellite Data

Tundra vegetation in the Teshekpuk Lake area of the Alaskan Arctic Coastal Plain was mapped to assess distribution and abundance of waterfowl habitats. Three SPOT satellite scenes were acquired and registered to a 20 m Universal Transverse Mercator grid. Two clustering techniques were used to develop statistical parameters by which the SPOT data were spectrally classified. A maximum likelihood algorithm that correlated spectral classes with land cover types was applied to the SPOT data. Field data were used to assist in spectral class labeling and vegetation descriptions. Twelve cover classes were mapped. The most common type was moist sedge meadow tundra (13.5%); the least common was moss/peat shoreline (0.2%). The moss/peat shoreline type, important to moulting geese and other waterfowl, was spectrally identified using supervised clustering techniques. All other land cover types were identified using unsupervised clustering techniques. Cover classes were described, and a tundra landscape profile produced.Key words: tundra land cover mapping, SPOT satellite data, Teshekpuk Lake, AlaskaOn a dressé une carte de la végétation de toundra dans la région du lac Teshekpuk de la plaine côtière arctique de l'Alaska afin d'évaluer la distribution et l'abondance de l'habitat de la sauvagine. On s'est procuré trois scènes prises par le satellite SPOT, qu'on a alignées sur un quadrillage de 20 m de la projection transverse universelle de Mercator. On a utilisé deux techniques d'agrégation pour élaborer des paramètres statistiques grâce auxquels on a classé en fonction du spectre les données provenant du SPOT. On a appliqué aux données du SPOT un algorithme de vraisemblance maximale corrélant les classes spectrales avec les types de couvert végétal. On a utilisé des données de terrain pour aider à nommer les classes spectrales et à décrire la végétation. On a cartographié 12 classes de couvert végétal, le plus commun étant la toundra de prairie à laîches humide (13,5 p. cent), et le moins abondant étant le littoral de mousse/tourbe (0,2 p. cent). On s'est servi de techniques d'agrégation dirigées pour identifier en fonction du spectre le type de mousse/tourbe, important pour les oies en période de mue et autre sauvagine. Tous les autres types de couvert végétal ont été identifiés à l'aide de techniques d'agrégation non dirigées. On a décrit les classes de couvert et établi un profil de paysage de toundra.Mots clés: cartographie du couvert végétal de la toundra, données provenant du satellite SPOT, lac Teshekpuk, Alask

Avian influenza at both ends of a migratory flyway: characterizing viral genomic diversity to optimize surveillance plans for North America

Although continental populations of avian influenza viruses are genetically distinct, transcontinental reassortment in low pathogenic avian influenza (LPAI) viruses has been detected in migratory birds. Thus, genomic analyses of LPAI viruses could serve as an approach to prioritize species and regions targeted by North American surveillance activities for foreign origin highly pathogenic avian influenza (HPAI). To assess the applicability of this approach, we conducted a phylogenetic and population genetic analysis of 68 viral genomes isolated from the northern pintail (Anas acuta) at opposite ends of the Pacific migratory flyway in North America. We found limited evidence for Asian LPAI lineages on wintering areas used by northern pintails in California in contrast to a higher frequency on breeding locales of Alaska. Our results indicate that the number of Asian LPAI lineages observed in Alaskan northern pintails, and the nucleotide composition of LPAI lineages, is not maintained through fall migration. Accordingly, our data indicate that surveillance of Pacific Flyway northern pintails to detect foreign avian influenza viruses would be most effective in Alaska. North American surveillance plans could be optimized through an analysis of LPAI genomics from species that demonstrate evolutionary linkages with European or Asian lineages and in regions that have overlapping migratory flyways with areas of HPAI outbreaks

Prevalence of Influenza A viruses in wild migratory birds in Alaska: Patterns of variation in detection at a crossroads of intercontinental flyways

<p>Abstract</p> <p>Background</p> <p>The global spread of the highly pathogenic avian influenza H5N1 virus has stimulated interest in a better understanding of the mechanisms of H5N1 dispersal, including the potential role of migratory birds as carriers. Although wild birds have been found dead during H5N1 outbreaks, evidence suggests that others have survived natural infections, and recent studies have shown several species of ducks capable of surviving experimental inoculations of H5N1 and shedding virus. To investigate the possibility of migratory birds as a means of H5N1 dispersal into North America, we monitored for the virus in a surveillance program based on the risk that wild birds may carry the virus from Asia.</p> <p>Results</p> <p>Of 16,797 birds sampled in Alaska between May 2006 and March 2007, low pathogenic avian influenza viruses were detected in 1.7% by rRT-PCR but no highly pathogenic viruses were found. Our data suggest that prevalence varied among sampling locations, species (highest in waterfowl, lowest in passerines), ages (juveniles higher than adults), sexes (males higher than females), date (highest in autumn), and analytical technique (rRT-PCR prevalence = 1.7%; virus isolation prevalence = 1.5%).</p> <p>Conclusion</p> <p>The prevalence of low pathogenic avian influenza viruses isolated from wild birds depends on biological, temporal, and geographical factors, as well as testing methods. Future studies should control for, or sample across, these sources of variation to allow direct comparison of prevalence rates.</p

Growth factors in multiple myeloma: a comprehensive analysis of their expression in tumor cells and bone marrow environment using Affymetrix microarrays

<p>Abstract</p> <p>Background</p> <p>Multiple myeloma (MM) is characterized by a strong dependence of the tumor cells on their microenvironment, which produces growth factors supporting survival and proliferation of myeloma cells (MMC). In the past few years, many myeloma growth factors (MGF) have been described in the literature. However, their relative importance and the nature of the cells producing MGF remain unidentified for many of them.</p> <p>Methods</p> <p>We have analysed the expression of 51 MGF and 36 MGF receptors (MGFR) using Affymetrix microarrays throughout normal plasma cell differentiation, in MMC and in cells from the bone marrow (BM) microenvironment (CD14, CD3, polymorphonuclear neutrophils, stromal cells and osteoclasts).</p> <p>Results</p> <p>4/51 MGF and 9/36 MGF-receptors genes were significantly overexpressed in plasmablasts (PPC) and BM plasma cell (BMPC) compared to B cells whereas 11 MGF and 11 MGFR genes were overexpressed in BMPC compared to PPC. 3 MGF genes (AREG, NRG3, Wnt5A) and none of the receptors were significantly overexpressed in MMC versus BMPC. Furthermore, 3/51 MGF genes were overexpressed in MMC compared to the the BM microenvironment whereas 22/51 MGF genes were overexpressed in one environment subpopulation compared to MMC.</p> <p>Conclusions</p> <p>Two major messages arise from this analysis 1) The majority of MGF genes is expressed by the bone marrow environment. 2) Several MGF and their receptors are overexpressed throughout normal plasma cell differentiation. This study provides an extensive and comparative analysis of MGF expression in plasma cell differentiation and in MM and gives new insights in the understanding of intercellular communication signals in MM.</p

13.1.15. Life History and Habitat Needs of the Black Brant

The black brant is a sea goose that depends on coastal habitats from high arctic nesting sites in Canada, Alaska, and Russia to wintering areas in the Pacific coastal states, the Baja California peninsula, and mainland Mexico estuaries. Population estimates are based on aerial surveys in Mexico, California, Oregon, and Washington during mid-winter. Despite much annual variability in estimates, a plot of the counts from 1964 to 1992 reveals a significant downward trend in the winter populations (Fig. 1). Three of four major colonies on the Yukon&#;Kuskokwim (Y&#;K) delta declined an average of 60% during the first half of the 1980’s. This is significant because about 79% of the world population of the black brant nest in these colonies (Table). Because few other breeding colonies have been consistently monitored, we have little understanding of their dynamics. Spring subsistence harvest in western Alaska coupled with fox predation on reduced Y&#;K delta populations, has limited the recovery of key nesting colonies. Degradation and loss of important staging and winter estuarine habitats from commercial and recreational development and disturbance are largely responsible for population reductions in British Columbia and the Pacific coastal states. In Mexico, industrial and recreational development in several estuaries may further limit winter habitats. Wildlife conservation agencies in Canada, Mexico, Russia, and the United States recently cooperated to examine population dynamics and factors that limit recovery of the black brant. This examination revealed important discoveries for management. This leaflet is a summary of these findings. More complete information on the life history of the black brant is in Bellrose (1980) and Palmer (1976)

Migration Behavior of Tundra Swans from the Yukon-Kuskokwim Delta, Alaska

Volume: 109Start Page: 679End Page: 69