Associations between coronal mass ejections and interplanetary shocks

Nearly continuous complementary coronal observations and interplanetary plasma measurements for the years 1979-1982 are compared. It is shown that almost all low latitude high speed coronal mass ejections (CME's) were associated with shocks at HELIOS 1. Some suitably directed low speed CME's were clearly associated with shocks while others may have been associated with disturbed plasma (such as NCDE's) without shocks. A few opposite hemisphere CME's associated with great flares seem to be associated with shocks at HELIOS

Response to ranibizumab therapy in neovascular AMD - an evaluation of good and bad responders

Background: Treatment of neovascular age-related macular degeneration (AMD) with Lucentis® shows a broad spectrum regarding the course of visual acuity (VA). While some patients show a good response (increase in VA), others disclose much less promising results. Patients and Methods: A retrospective data analysis of all eyes treated for neovascular AMD at the University Hospital of Zurich, Switzerland for at least 12 months was carried out. The courses of VA between the 90th (good responders, GR) and the 10th (bad responders, BR) percentiles were compared at 3, 12 and 24 months from baseline. An analysis regarding demographic data, lesion type and size as well as injection frequency and visits was done and predictive factors for GR and BR were evaluated. Results: Marked differences in the course of VA between GR (n = 30) and BR (n = 30) are already observed 3 months from baseline. In GR the gains in VA after 3, 12 and 24 were 15.7 ± 9 letters ETDRS, 25.3 ± 7 and 14.0 ± 14. BR showed a deterioration of 8.3 ± 11 letters ETDRS after 3, 22.1 ± 8 after 12 and 23.6 ± 13 after 24 months. The gender distribution was equal with a higher percentage of female patients (64 % in BR and 66 % in GR). The baseline VA was statistically significantly lower in GR (45.7 ± 10 vs. 55.4 ± 11, p < 0.05) than in BR. No other significant differences in baseline data were found, and no predictor for group membership could be identified. Conclusions: Only the course of VA in the first three months seems to be of value for an estimation of the response to treatment. In the future the response to treatment in the early phase may influence the treatment algorithm and the injection frequency

Precision neutron interferometric measurement of the nd coherent neutron scattering length and consequences for models of three-nucleon forces

We have performed the first high precision measurement of the coherent neutron scattering length of deuterium in a pure sample using neutron interferometry. We find b_nd = (6.665 +/- 0.004) fm in agreement with the world average of previous measurements using different techniques, b_nd = (6.6730 +/- 0.0045) fm. We compare the new world average for the nd coherent scattering length b_nd = (6.669 +/- 0.003) fm to calculations of the doublet and quartet scattering lengths from several modern nucleon-nucleon potential models with three-nucleon force (3NF) additions and show that almost all theories are in serious disagreement with experiment. This comparison is a more stringent test of the models than past comparisons with the less precisely-determined nuclear doublet scattering length of a_nd = (0.65 +/- 0.04) fm.Comment: 4 pages, 4 figure

Mesoscale simulations of surfactant dissolution and mesophase formation

The evolution of the contact zone between pure surfactant and solvent has been studied by mesoscale simulation. It is found that mesophase formation becomes diffusion controlled and follows the equilibrium phase diagram adiabatically almost as soon as individual mesophases can be identified, corresponding to times in real systems of order 10 microseconds.Comment: 4 pages, 2 figures, ReVTeX

Wind erosion control using crop residue II. Effects on millet establishment and yields

Effects of three levels of millet stover residue (0, 500, and 2000 kg ha−1) on establishment and growth of pearl millet (Pennisetum glaucum (L.) R.Br) were determined in a wind-erosion-affected area in Niger, West Africa, during 1991 and 1992. The extent of millet seedlings buried by blown soil in plots with 500 kg ha−1residues was similar to that of control plots. A residue amount of 2000 kg ha−1 reduced the extent of covered millet, but did not provide complete protection during severe sand storms. Partial covering of millet seedlings by blown soil decreased biomass yields compared to uncovered millet. Grain production, averaged over two years, was about 500 kg ha−1 for the control, 570 kg ha−1 with 500 kg ha−1residue, and 730 kg ha−1 with 2000 kg ha−1residue. Increased yields were caused by both winderosion protection and direct growth stimulating effects of residue. Stover yields for all treatments in both years were less than 2000 kg ha−1 and thus insufficient to sustain the levels required for protection of crops against winderosion damages. An increase in dry matter left in the field or the implementation of alternative winderosioncontrol measures is needed for sustainable crop production in wind-erosion-affected area

Wind erosion control using crop residue I. Effects on soil flux and soil properties

Effects of millet stover residue (0, 500, and 2000 kg ha−1) onwinderosionand surface soilproperties were determined from 1991 to 1993 at the ICRISAT Sahelian Center in Niger, West Africa. Soilflux 0.1 m above the ground was significantly reduced with 2000 kg ha−1residue but not with 500 kg ha−1. Topographic measurements indicated that soil removed from the soil surface was less with either residue level than in the control. After 2 y, the soil surface (0–0.01 m) of both residue treatments had less coarse sand than the control, but more fine sand and clay, more organic carbon and an increased cation exchange capacity. The organic-C content of blown material was greater than that of surface soil. An amount of 500 kg ha−1residue can be considered useful for soil conservation, but 2000 kg ha−1 are required for a significant reduction of soilflux caused during severe winderosion event

Wind erosion in the Southern Sahelian Zone and induced constraints to pearl millet production

On the sandy soils in the Southern Sahelian Zone, wind erosion owing to frequent short sand storms, especially at the beginning of the rainy season, is one of the constraints to crop growth. Sand storms and their effects on millet burial and growth were monitored during the 1990 growing season at the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT) Sahelian Center, Niamey, Niger. During the growing season, the accumulated sand captured at 0.1 m above the soil surface attained 1262 kg m−2 vertical sampler opening. Ninety per cent of the millet pockets sown with the first rains were covered at 22 days after emergence and the crop was resown. During one single wind erosion event, 384 kg m−2 of sand was trapped and 40% of all millet pockets were totally covered. Surviving plants from the partially covered pockets showed delays in growth and development. The maximum plant height and leaf number were lower with a significant reduction in the leaf area index. Grain yield from unaffected pockets was nearly twice that of the pockets which were partially covered. Protection measures against wind erosion may have a potential to stabilize millet production in the Southern Sahelian Zone

Domain walls and perturbation theory in high temperature gauge theory: SU(2) in 2+1 dimensions

We study the detailed properties of Z_2 domain walls in the deconfined high temperature phase of the d=2+1 SU(2) gauge theory. These walls are studied both by computer simulations of the lattice theory and by one-loop perturbative calculations. The latter are carried out both in the continuum and on the lattice. We find that leading order perturbation theory reproduces the detailed properties of these domain walls remarkably accurately even at temperatures where the effective dimensionless expansion parameter, g^2/T, is close to unity. The quantities studied include the surface tension, the action density profiles, roughening and the electric screening mass. It is only for the last quantity that we find an exception to the precocious success of perturbation theory. All this shows that, despite the presence of infrared divergences at higher orders, high-T perturbation theory can be an accurate calculational tool.Comment: 75 pages, LaTeX, 14 figure