Understanding the drivers of near-surface winds in Adélie Land, East Antarctica

Near-surface winds play a crucial role in the climate of Antarctica, but accurately quantifying and understanding their drivers is complex. They result from the contribution of two distinct families of drivers: the large-scale pressure gradient and surface-induced pressure gradients known as katabatic and thermal wind. The extrapolation of vertical potential temperature above the boundary layer down to the surface enables us to separate and quantify the contribution of these different pressure gradients in the momentum budget equations. Using this method applied to outputs of the regional atmospheric model MAR at a 3-hourly resolution, we find that the seasonal and spatial variability in near-surface winds in Adélie Land is dominated by surface processes. On the other hand, high-frequency temporal variability (3-hourly) is mainly controlled by large-scale variability everywhere in Antarctica, except on the coast. In coastal regions, although the katabatic acceleration surpasses all other accelerations in magnitude, none of the katabatic or large-scale accelerations can be identified as the single primary driver of near-surface wind variability. The angle between the large-scale acceleration and the surface slope is a key factor in explaining strong wind speed events: the highest-wind-speed events happen when the katabatic and large-scale forcing are aligned, although each acceleration, when acting alone, can also cause strong wind speed. This study underlines the complexity of the drivers of Antarctic surface winds and the value of the momentum budget decomposition to identify drivers at different spatial and temporal scales.</p

Expression of human cytomegalovirus immediate early protein IE1 in insect cells: splicing of RNA and recognition by CD4+ T-cell clones

International audienc

Expression of human cytomegalovirus immediate early protein IE1 in insect cells: splicing of RNA and recognition by CD4+ T-cell clones

International audienc

Truncated forms of human complement factor H.

By the use of Western-blot analyses with polyclonal anti-(Factor H) antibodies, two low-Mr protein species of Mr 41,000 and 37,000 under non-reducing conditions and 43,000 and 40,000 under reducing conditions are consistently detected together with the well-known 155,000-Mr Factor H in human plasma and serum. These two additional species are also found in plasma, urine and synovial fluids. The 41,000-Mr species but not the 37,00-Mr species is detected by a monoclonal anti-(Factor H) antibody directed at the N-terminal part of Factor H. The 37,000-Mr species but not the 41,000-Mr species is detected by a monoclonal anti-(Factor H) antibody directed at the C-terminal part of Factor H. The 41,000-Mr and 37,000-Mr species are different from the well-characterized 36,000-Mr N-terminal tryptic fragment of Factor H. They are likely to represent translational products of the short Factor H mRNA species of 1.8 kb and 1.2-1.5 kb occurring in human liver that we have recently described