BIRD - A Microsatellite for Hot Spot Detection

The BIRD mission of the German Aerospace Centre shall demonstrate the scientific and technological value and the technical and programmatic feasibility of a remote sensing small satellite mission under low budget constraints. The payload -a new generation of cooled infrared detectors- is adapted to the mission objective - the investigation of hot spots caused by forest fires or volcanic activities completed by the diagnosis of vegetation conditions and changes. BIRD -the Bispectral Infra-Red Detector- is a three-axis stabilised spacecraft within a volume of 0.21 m3 and a mass of 88 kg. In flight configuration with one fixed and two deployed solar panels, providing 40 W average and 200 W peak power, the spacecraft dimensions are 620x 1600x 620 mm3 • Although compatible to several launchers due to the highly compact design, the launch is scheduled for mid 2000 as a piggy-back payload. To fit in this time scale a modular design was chosen for parallel development, manufacturing and integration of all functional segments. The article gives an overview of the mission objectives and some of the main design aspects as well as shows the status of work of the space segment

Neurophysiological correlates of excitement in men with recent-onset psychosis

Objective: Right frontal function, as indicated by the N200 component of the event-related potential during target detection, has previously been associated with excitement (excitement, impulsivity, hostility, uncooperativeness) in men with a long-term diagnosis of schizophrenia. The current study investigated excitement in relation to N200 in men who had recently experienced their first episode of psychosis. Subjects and methods: Twenty men who had recently suffered their first psychotic episode underwent a clinical interview and auditory oddball task. Results: Multiple linear regression analysis showed that 58% of the variance in the excitement symptom cluster was explained by a positive association with frontal midline N200 amplitude and an inverse association with right frontal N200 amplitude. The latter was not apparent in the initial correlation, suggesting suppression by the midline activity. These associations were not explained by drug use, medication or negative symptoms. However, the correlation between excitement and midline N200 was stronger in drug users, and that between right frontal N200 and excitement was stronger in nonusers. Conclusion: Findings support the independent contributions to excitement of mechanisms reflected in midline and right frontal N200 amplitude respectively during the early stages of psychosis

Superconducting Fluctuations and the Pseudogap in the Slightly-overdoped High-Tc Superconductor TlSr2CaCu2O6.8: High Magnetic Field NMR Studies

From measurements of the ^{63}Cu Knight shift (K) and the nuclear spin-lattice relaxation rate (1/T_{1}) under magnetic fields from zero up to 28 T in the slightly overdoped superconductor TlSr_{2}CaCu_{2}O_{6.8} (T_{c}=68 K), we find that the pseudogap behavior, {\em i.e.}, the reductions of 1/T_{1}T and K above T_{c} from the values expected from the normal state at high T, is strongly field dependent and follows a scaling relation. We show that this scaling is consistent with the effects of the Cooper pair density fluctuations. The present finding contrasts sharply with the pseudogap property reported previously in the underdoped regime where no field effect was seen up to 23.2 T. The implications are discussed.Comment: 10 pages, 4 GIF figures, to be published in Phys. Rev. Let