NASA Earth Science Disasters Program Tropical Cyclone Response

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ABSENCE OF HAEMATOZOA IN BREEDING MACARONI EUDYPTES CHRYSOLOPHUS AND ROCKHOPPER E. CHRYSOCOME PENGUINS AT MARION ISLAND

Haematozoan infections cause the death of penguins in captivity, but seldom in the wild. No haematozoa were found in 89 blood smears taken from macaroni penguins Eudyptes chrysolophus or 80 smears from eastern rockhopper penguins E. chrysocome filholi at subantarctic Marion Island between October and November 2001. Discussion centres on the possibility of vector introduction and establishment under conditions of climatic and/or anthropogenic change.Afr. J. mar. Sci. 25: 499–50

Weather Impact on Airport Performance

Weather events have a significant impact on airport performance and cause delayed operations if the airport capacity is constrained. We provide quantification of the individual airport performance with regards to an aggregated weather-performance metric. Specific weather phenomena are categorized by the air traffic management airport performance weather algorithm, which aims to quantify weather conditions at airports based on aviation routine meteorological reports. Our results are computed from a data set of 20.5 million European flights of 2013 and local weather data. A methodology is presented to evaluate the impact of weather events on the airport performance and to select the appropriate threshold for significant weather conditions. To provide an efficient method to capture the impact of weather, we modelled departing and arrival delays with probability distributions, which depend on airport size and meteorological impacts. These derived airport performance scores could be used in comprehensive air traffic network simulations to evaluate the network impact caused by weather induced local performance deterioration

Monopolelike probes for quantitative magnetic force microscopy: calibration and application

A local magnetization measurement was performed with a Magnetic Force Microscope (MFM) to determine magnetization in domains of an exchange coupled [Co/Pt]/Co/Ru multilayer with predominant perpendicular anisotropy. The quantitative MFM measurements were conducted with an iron filled carbon nanotube tip, which is shown to behave like a monopole. As a result we determined an additional in-plane magnetization component of the multilayer, which is explained by estimating the effective permeability of the sample within the \mu*-method.Comment: 3 pages, 3 figure

The role of carbon for superconductivity in MgCx_{x}Ni3_{3} from specific heat

The influence of carbon deficiency on superconductivity of MgCNi$_{3}$ is investigated by specific heat measurements in the normal and superconducting state. In order to perform a detailed analysis of the normal state specific heat, a computer code is developed which allows for an instantaneous estimate of the main features of the lattice dynamics. By analyzing the evolution of the lattice vibrations within the series and simultaneously considering the visible mass enhancement, the loss in the electron-phonon coupling can be attributed to significant changes of the prominent Ni vibrations. The present data well supports the recently established picture of strong electron-phonon coupling and ferromagnetic spin fluctuations in this compound.Comment: 4 pages, latex, corrections to the text, one reference added, one figure correcte

Quantitative assessment of pinning forces and the superconducting gap in NbN thin films from complementary magnetic force microscopy and transport measurements

Epitaxial niobium-nitride thin films with a critical temperature of Tc=16K and a thickness of 100nm were fabricated on MgO(100) substrates by pulsed laser deposition. Low-temperature magnetic force microscopy (MFM) images of the supercurrent vortices were measured after field cooling in a magnetic field of 3mT at various temperatures. Temperature dependence of the penetration depth has been evaluated by a two-dimensional fitting of the vortex profiles in the monopole-monopole model. Its subsequent fit to a single s-wave gap function results in the superconducting gap amplitude Delta(0) = 2.9 meV = 2.1*kB*Tc, in perfect agreement with previous reports. The pinning force has been independently estimated from local depinning of individual vortices by lateral forces exerted by the MFM tip and from transport measurements. A good quantitative agreement between the two techniques shows that for low fields, B << Hc2, MFM is a powerful and reliable technique to probe the local variations of the pinning landscape. We also demonstrate that the monopole model can be successfully applied even for thin films with a thickness comparable to the penetration depth.Comment: 6 pages, 6 figures, 2 table

The Allan Hills Meteorite Icefield-An alternative view

More than 1300 meteorites have been found on the surface of blue icefields in North Victorialand, Antarctica. The Allan Hills Icefield (about 100 km^2) has exceptionally high meteorite concentrations while other icefields to the West have much smaller concentrations. Measurements of the rates of ablation and of horizontal displacement of the ice surface near the Allan Hills have been conducted since 1978 at a 20 station triangulation network. These data show that the horizontal ice velocity at the most active stations is about one m/yr and less at the high meteorite concentration site. Ablation of the ice surface averages about 4.2 em/yr. Measurements of the oxygen isotopic composition of surface ice along the triangulation network show a rather large scatter of about 8δ^(18)O‰. This indicates that the ice comes from different areas or possibly is different in age. The terrestrial ages of Allan Hills meteorites are between 0 and 700,000 years, with only a few older than 400,000 years. A model for the appearance of meteorites on blue ice surfaces in Antarctica is that specimens are carried within the moving ice sheet to stagnant areas where they are uncovered by the ablation process (see e.g. Bull and Lipschutz, 1982). These areas ("emergent zones") are fed by ice that originally accumulated as snow at the source regions of the ice. This model accounts for the general occurrence of meteorites on blue ice fields but an additional mechanism is needed to explain the high concentrations found at the Allan Hills. It is suggested that this icefield has concentrated meteorites primarily by horizontal movement of the ice from the emergent zones located to the west of the concentration zone. These meteorites are transported by surface compressive flow of the ice into the Allan Hills Meteorite Icefield and left stranded in an area where ice is only lost by the ablation process. This model seems to be in agreement with all field and laboratory observations