Turbulent mixing and the formation of an intermediate nepheloid layer above the Siberian continental shelf break

Intermediate nepheloid layers (INLs) form important pathways for the cross-slope transport and vertical export of particulate matter, including carbon. While intermediate maxima in particle settling fluxes have been reported in the Eurasian Basin of the Arctic Ocean, direct observations of turbid INLs above the continental slope are still lacking. In this study, we provide the first direct evidence of an INL, coinciding with enhanced mid-water turbulent dissipation rates, over the Laptev Sea continental slope in summer 2018. Current velocity data show a period of enhanced downslope flow with depressed isopcynals, suggesting that the enhanced turbulent dissipation is probably the consequence of the presence of an unsteady lee wave. Similar events occur mostly during ice free periods, suggesting an increasing frequency of episodic cross-slope particle transport in the future. The discovery of the INL and the episodic generation mechanism provide new insights into particle transport dynamics in this rapidly changing environment

Increasing nutrient fluxes and mixing regime changes in the eastern Arctic Ocean

Primary productivity in the Arctic Ocean is experiencing dramatic changes linked to the receding sea ice cover. The vertical transport of nutrients from deeper water layers is the limiting factor for primary production. Here, we compare coincident profiles of turbulence and nutrients from the Siberian Seas in 2007, 2008, and 2018. In all years, the water column structure in the upstream region of the Arctic Boundary Current promotes upward nutrient transport, in contrast to the regions further downstream, and there are first indications for an eastward progression of these conditions. In summer 2018, strongly enhanced vertical nitrate flux and primary production above the continental slope were observed, likely related to a remote storm. The estimated contribution of these elevated fluxes above the slope to the Pan-Arctic vertical nitrate supply is comparable with the basin-wide transport, and is predicted to increase with declining sea ice cover in the future

The Effects of Aquatic Predator Chemicals (Crayfish Kairomones) on the Development of Ampibians (Lithobates Sylvatica)

Undergraduate Basi

FIRST SPECIES OF HESPEROPILIO (OPILIONES, CADDOIDEA, CADDIDAE) FROM SOUTH AMERICA

Volume: 34Start Page: 46End Page: 5

FIRST SPECIES OF AUSTROPSOPILIO (OPILIONES, CADDOIDEA, CADDIDAE) FROM SOUTH AMERICA

Volume: 31Start Page: 20End Page: 2

Dairies adopt TQM to improve milk quality and food safety

In an effort to manage antibiotics and prevent residues in meat and milk, the principles of Total Quality Management were applied to dairy farm operations. Six California dairies participated in the National Dairy Total Quality Management Program, which included dairies in 30 states. Dairy producers, their veterinarians, the UC Cooperative Extension dairy farm advisors and Veterinary Medicine Extension veterinarians collaborated during the study. During the project, all six dairies developed written treatment plans to assure that drug withdrawal deadlines were being met. Most of the participating producers judged the management protocols, treatment protocols and treatment records to be “very useful” or “somewhat useful.” Perhaps the greatest benefit was increased communication between the dairy management and its workers for a better understanding of what was expected of each worker and who was accountable

Increased Frequency of Pre–Pro B Cells in the Bone Marrow of New Zealand Black (NZB) Mice: Implications for aDevelopmental Block in B Cell Differentiation

Reductions in populations of both Pre-B cell (Hardy fractions D) and Pro-B cells (Hardy fractions B–C) have been described in association with murine lupus. Recent studies of B cell populations, based on evaluation of B cell differentiation markers, now allow the enumeration and enrichment of other stage specific precursor cells. In this study we report detailed analysis of the ontogeny of B cell lineage subsets in New Zealand black (NZB) and control strains of mice. Our data suggest that B cell development in NZB mice is partially arrested at the fraction A Pre–Pro B cell stage. This arrest at the Pre-Pro B cell stage is secondary to prolonged lifespan and greater resistance to spontaneous apoptosis. In addition, expression of the gene encoding the critical B cell development transcription factor BSAP is reduced in the Pre–Pro B cell stage in NZB mice. This impairment may influence subsequent B cell development to later stages, and thereby accounts for the down-regulation of the B cell receptor component Igα (mb-1). Furthermore, levels of expression of the Rug2, λ5 and Igβ (B29) genes are also reduced in Pre–Pro B cells of NZB mice. The decreased frequency of precursor B cells in the Pre–Pro B cell population occurs at the most primitive stage of B cell differentiation