Screening by coral green fluorescent protein (GFP)-like chromoproteins supports a role in photoprotection of zooxanthellae

Green fluorescent protein (GFP)-like pigments are responsible for the vivid colouration of many reef-building corals and have been proposed to act as photoprotectants. Their role remains controversial because the functional mechanism has not been elucidated. We provide direct evidence to support a photoprotective role of the non-fluorescent chromoproteins (CPs) that form a biochemically and photophysically distinct group of GFP-like proteins. Based on observations of Acropora nobilis from the Great Barrier Reef, we explored the photoprotective role of CPs by analysing five coral species under controlled conditions. In vitro and in hospite analyses of chlorophyll excitation demonstrate that screening by CPs leads to a reduction in chlorophyll excitation corresponding to the spectral properties of the specific CPs present in the coral tissues. Between 562 and 586 nm, the CPs maximal absorption range, there was an up to 50 % reduction of chlorophyll excitation. The screening was consistent for established and regenerating tissue and amongst symbiont clades A, C and D. Moreover, among two differently pigmented morphs of Acropora valida grown under identical light conditions and hosting subclade type C3 symbionts, high CP expression correlated with reduced photodamage under acute light stress

A possible solution of the grain boundary problem for applications of high-Tc superconductors

It is shown that the critical current density of high-Tc wires can be greatly enhanced by using a threefold approach, which consists of grain alignment, doping, and optimization of the grain architecture. According to model calculations, current densities of 4x10^6 A/cm2 can be achieved for an average grain alignment of 10 degree at 77K. Based on this approach, a road to competitive high-Tc cables is proposed.Comment: 3 pages, 5 figure

Magnetic microstructure of nanostructured Fe, studied by small angle neutron scattering

Small angle neutron scattering (SANS) was applied to achieve insight into the magnetic correlations in nanostructured Fe. The results confirm the expected microstructure involving ferromagnetic grains and a nonmagnetic or weakly magnetic interface region, the interfaces occupying about half the specimen volume. The SANS measurements further reveal that in nanostructured Fe the magnetic correlations are not confined to single grains, but are extended across the interfaces and result in the alignment of the magnetization over several hundreds of grains. An external field of 1.5 kOe is not sufficient for complete magnetic alignment of the entire specimen. However, the long-range magnetic correlations are considerably disturbed by this field. Reducing the external magnetic field to zero causes the magnetic correlations to resume microstructural characteristics similar to what they had in the original stat

A configuration system for the ATLAS trigger

The ATLAS detector at CERN's Large Hadron Collider will be exposed to proton-proton collisions from beams crossing at 40 MHz that have to be reduced to the few 100 Hz allowed by the storage systems. A three-level trigger system has been designed to achieve this goal. We describe the configuration system under construction for the ATLAS trigger chain. It provides the trigger system with all the parameters required for decision taking and to record its history. The same system configures the event reconstruction, Monte Carlo simulation and data analysis, and provides tools for accessing and manipulating the configuration data in all contexts.Comment: 4 pages, 2 figures, contribution to the Conference on Computing in High Energy and Nuclear Physics (CHEP06), 13.-17. Feb 2006, Mumbai, Indi

Sintering characteristics of nanocrystalline TiO2—A study combining small angle neutron scattering and nitrogen absorption-BET

Small angle neutron scattering (SANS) was employed to characterize the pore structure of nanophase TiO2 ceramic materials compacted at different temperatures. Nanophase samples, produced by inert gas condensation, were compacted at 25, 290, 413, and 550 °C using a pressure of 1 GPa. The pore size distribution of the sample compacted at room temperature was very broad, with sizes ranging from 3-30 nm and pores comprising 38% of the sample volume. Compaction at 290 and 413 °C reduced the pore volume to 25% and 20%, respectively, by eliminating pores at both the small and large ends of the distribution. Compaction at 550 °C resulted in a pore volume that was less than 8%. Complications in the SANS analysis arising from the scattering from grain boundaries are discussed. The results from SANS are compared with those derived from nitrogen absorption, BET, measurement

The Climatology of Blocking Anticyclones for the Northern and Southern Hemispheres: Block Intensity as a Diagnostic

A 30-yr climatology of blocking events was compiled by stratifying the data into seasonal and three regional categories for both the Northern and Southern Hemispheres using the NCEP-NCAR reanalyses. Several characteristics of blocking anticyclones were included in the study and these were frequency of occurrence, preferred formation regions, duration, blocking days, and intensity. The block intensity (BI) calculation was modified successfully from a previous study in order to automate the procedure for use with large datasets, and it is applied for the first time to derive a long-term observational record of this quantity. This modification also makes BI suitable for use as a diagnostic tool. Blocking events in the Northern (Southern) Hemisphere were the most persistent and strongest during the cold season and over the Atlantic (Pacific) region, as found using BI to measure intensity. The characteristics of blocking events derived in this study were compared to previous long-term climatological studies and across each hemisphere. It was found that the temporal and spatial distributions in both hemispheres were similar to those of longer-term studies. The interannual variability of blocking was also examined with respect to ENSO-related variability for the entire blocking year. It was found that Northern (Southern) Hemisphere blocking events were stronger and more frequent during La Nin˜a (El Nin˜o) years, a result that is consistent with cyclone variability in each hemisphere. Additionally, these results were compared with previously published studies of interannual variability in blocking occurrence