Multi-Step Ordering in Kagome and Square Artificial Spin Ice

We show that in colloidal models of artificial kagome and modified square ice systems, a variety of ordering and disordering regimes occur as a function of biasing field, temperature, and colloid-colloid interaction strength, including ordered monopole crystals, biased ice rule states, thermally induced ice rule ground states, biased triple states, and disordered states. We describe the lattice geometries and biasing field protocols that create the different states and explain the formation of the states in terms of sublattice switching thresholds. For a system prepared in a monopole lattice state, we show that a sequence of different orderings occurs for increasing temperature. Our results also explain several features observed in nanomagnetic artificial ice systems under an applied field.Comment: 16 pages, 11 postscript figure

More Evidence that Depressive Symptoms Predict Mortality in COPD Patients: Is Type D Personality an Alternative Explanation?

The present study attempted to replicate our previous finding that depressive symptoms are a risk factor for mortality in stable chronic obstructive pulmonary disease (COPD), but in a different population with a different measure of depressive symptoms. We further investigated whether type D personality is associated with mortality in patients with COPD and whether it explains any relationship observed between depressive symptoms and mortality. In 122 COPD patients, mean age 60.8 +/- 10.3 years, 52% female, and mean forced expiratory volume in 1 s (FEV(1)) 41.1 +/- 17.6%pred, we assessed body mass index, post bronchodilator FEV(1), exercise capacity, depressive symptoms with the Hospital Anxiety and Depression Scale, and type D with the Type D Scale. In the 7 years follow-up, 48 (39%) deaths occurred. The median survival time was 5.3 years. Depressive symptoms (hazard ratio = 1.07, 95% confidence intervals = 1.00-1.14) were an independent risk factor for mortality. Type D was not associated with mortality. We can rule out type D as an explanation for the relationship between depressive symptoms and mortality observed in this sample. However, ambiguity remains as to the interpretation of the value of depressive symptoms in predicting death

The intensity of the Earth's magnetic field over the past 160 million years

In contrast to our detailed knowledge of the directional behaviour of the Earth's magnetic field during geological and historical times, data constraining the past intensity of the field remain relatively scarce. This is mainly due to the difficulty in obtaining reliable palaeointensity measurements, a problem that is intrinsic to the geological materials which record the Earth's magnetic field. Although the palaeointensity database has grown modestly over recent years^(3-5), these data are restricted to a few geographical locations and more than one-third of the data record the field over only the past 5Myr-the most recent database covering the time interval from 5 to 160Myr contains only about 100 palaeointensity measurements. Here we present 21 new data points from the interval 5-160Myr obtained from submarine basalt glasses collected from locations throughout the world's oceans. Whereas previous estimates for the average dipole moment were comparable to that of the Earth's present field6, the new data suggest an average dipole moment of (4.2 +/- 2.3) * 10^22 Am², or approximately half the present magnetic-field intensity. This lower average value should provide an important constraint for future efforts to model the convective processes in the Earth's core which have been responsible for generating the magnetic field

Report and preliminary results of Meteor Cruise 29/2, Montevideo-Rio de Janeiro, 15.7.-8.8.1994.

The three legs of METEOR Cruise 29 (Expedition Geo Bremen South Atlantic 1994) continued a long-term geoscientific study aimed at reconstructing the mass budget and current systems of the South Atlantic during the late Quaternary. This program is financially supported as a Special Research Project (Sonderforschungsbereich 261) by the German Science Foundation (Deutsche Forschungsgemeinschaft) since 1989.The main objective of the second leg of the 29th METEOR Cruise was to sample sedimentary deposits along transects across the continental margin off Uruguay and on the flanks of the Rio Grande Rise and Santos Plateau east and west of the Vema Channel. To systematically supplement the core material recovered during the 1993 METEOR Cruise M23/2 and the preceding Leg M29/1, the gravity corer, large box corer and multicorer were employed. Detailed analyses of this sample collection with geochemical, geophysical, micropaleontological and isotopic methods will determine the regional sedimentation patterns and their mostly climatically controlled late Quaternary variations. In the actual working areas these are predominantly influenced by water masses from high northern and southern latitudes and gravitational processes on the South American continental slope.During the entire leg continuous geoacoustic recordings were performed using the ship's systems PARASOUND and HYDROSWEEP. To determine the specific characteristics of a depositional regime which to a large extent is dominated by intensive bottom water currents, a high resolution survey with a series of echographic and bathymetric profiles combined with additional sediment sampling was planned for selected regions of apparently migrating mud waves in the central Argentine Basin. At a number of stations separate sediment core material was retrieved for geochemical analyses. Sampling of the water column with a multinet and a multiple water sampler complete the scientific program of the cruise.5

Report and preliminary results of SONNE-Cruise SO 86, Buenos Aires - Capetown, 22.4. - 31.5.93.

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Report and preliminary results of Meteor Cruise 38/2 Recife - Las Palmas, 4.3.-14.4.1997.

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