Remotely sensed surface water extent as an indicator of short-term changes in ecohydrological processes in sub-Saharan Western Africa

The highly variable rainfall in the arid and semi-arid regions of sub-Saharan Western Africa drives both surface water availability and vegetation cover. Recent studies have established linkages between rainfall and vegetation cover at local to regional scales, but no study related yet remote sensing derived rainfall and vegetation cover to the available surface water. A new dataset based on SPOT VEGETATION (VGT) represents surface water bodies (SWB) in the arid and semi-arid regions of sub-Saharan Western Africa. Water bodies represent the integrated hydrological response of a catchment, and changes in their spatial extent involve complex interactions at the catchment scale. We analyzed time series of remotely sensed vegetation cover, rainfall and surface water extent for the period 1999–2008, and could detect and statistically demonstrate the links between these biophysical variables. Our findings for two regions in Mali and Burkina Faso suggest that vegetation cover is positively related to the amount of available surface water for those catchments that are mainly covered by annual plants. The observed relationships between remotely sensed variables allow developing ecological indicators that can indicate short-term changes in arid and semi-arid ecosystems at local to regional scales.     

Multi-temporal compositing approaches for SPOT-4 VEGETATION

Five image compositing criteria for Système pour l'Observation de la Terre (SPOT)-4 VEGETATION data were compared. Selecting the pixel that satisfies a given criterion from a monthly set of daily images produces the composite image. The criteria applied are: maximization of Normalized Difference Vegetation Index (NDVI); minimization of the red channel; maximization of NDVI followed by minimization of short-wave infrared (SWIR); selection of the third lowest value of near-infrared (NIR); and selection of the third lowest value of an albedo-like index, designated by 'darkness'. Visual and quantitative analysis indicate that the last approach produces the cleanest images.     

Practical quality assurance for standards-based, high-availability middleware

Telecommunications technologies are undergoing a major paradigm shift. Standards-based, off-the-shelf components and the Internet are gaining wide acceptance. The success of this move is strongly dependent upon the quality and availability of these technologies.Practical quality assurance in this environment can take advantage of the tools and methods developed when carrier-grade systems for the telecommunications market were being deployed. Besides standard test methods, availability-related methods for redundant hardware and software components are applied. Statistics are available that prove the success of this approach. The statistical data are derived from the deployment of the commercial product RTP⁴ Continuous Services, a standards-based high-availability middleware.Additional momentum has been gained in the Service Availability Forum (www.saforum.org), where the interface standards are validated and certified in independent test processes.     

Metastatic melanoma of the parotid gland (author''s transl)

An electronic measuring instrument, which automatically calculates the rectal potential difference, has been developed to determine mineralocorticoid activity in patients with primaroid disorders. A special probe with a disposable tip enables measurements to be made on successive patients without prior cleaning of the probe. The technique, results and their clinical implications are discussed. A highly significant correlation between plasma aldosterone and rectal potential difference is demonstrated.     

GLC2000: a new approach to global land cover mapping from Earth observation data

A new global land cover database for the year 2000 (GLC2000) has been produced by an international partnership of 30 research groups coordinated by the European Commission's Joint Research Centre. The database contains two levels of land cover information—detailed, regionally optimized land cover legends for each continent and a less thematically detailed global legend that harmonizes regional legends into one consistent product. The land cover maps are all based on daily data from the VEGETATION sensor on‐board SPOT 4, though mapping of some regions involved use of data from other Earth observing sensors to resolve specific issues. Detailed legend definition, image classification and map quality assurance were carried out region by region. The global product was made through aggregation of these. The database is designed to serve users from science programmes, policy makers, environmental convention secretariats, non‐governmental organizations and development‐aid projects. The regional and global data are available free of charge for all non‐commercial applications from http://www.gvm.jrc.it/glc2000.     

Neural network application for cloud detection in SPOT VEGETATION images

SPOT VEGETATION is a recent sensor at 1 km resolution for land surface studies. Cloud detection based on this sensor is complicated by the absence of a thermal band. An artificial neural network was thus trained for the cloud detection on atmospherically corrected S1 daily data and on top of the atmosphere reflectance P data, from the SPOT VEGETATION system. It consists of a multi‐layer perceptron with one hidden sigmoid layer, trained with the Levenberg–Marquardt back‐propagation algorithm and generalized by the Bayesian regularization. Two neural networks allowed optimal cloud detections to be obtained. The first used all four bands of S1 data with 13 hidden nodes, and the second employed all four bands of P data with 11 hidden nodes. The multiple‐layer perceptrons lead to a cloud detection accuracy of 98.0% and 97.6% for S1 and P data, respectively, when trained to map three predefined values that classify cloud, water and land. The network was further evaluated using three SPOT VEGETATION images taken at different dates. The network detected not only bright thick clouds but also thin or less bright clouds. The analysis demonstrated the superior classification of the network over the standard cloud masks provided with the data.     

A Structure-Activity Relationship Study of Bimodal BODIPY-Labeled PSMA-Targeting Bioconjugates

The aim of this study was to identify a high-affinity BODIPY peptidomimetic that targets the prostate-specific membrane antigen (PSMA) as a potential bimodal imaging probe for prostate cancer. For the structure-activity study, several BODIPY (difluoroboron dipyrromethene) derivatives with varying spacers between the BODIPY dye and the PSMA Glu-CO-Lys binding motif were prepared. Corresponding affinities were determined by competitive binding assays in PSMA-positive LNCaP cells. One compound was identified with comparable affinity (IC₅₀=21.5±0.1 nM) to Glu-CO-Lys-Ahx-HBED-CC (PSMA-11) (IC₅₀=18.4±0.2 nM). Radiolabeling was achieved by Lewis-acid-mediated ¹⁹F/¹⁸F exchange in moderate molar activities (∼0.7 MBq nmol⁻¹) and high radiochemical purities (>99 %) with mean radiochemical yields of 20–30 %. Cell internalization of the ¹⁸F-labeled high-affinity conjugate was demonstrated in LNCaP cells showing gradual increasing PSMA-mediated internalization over time. By fluorescence microscopy, localization of the high-affinity BODIPY-PSMA conjugate was found in the cell membrane at early time points and also in subcellular compartments at later time points. In summary, a high-affinity BODIPY-PSMA conjugate has been identified as a suitable candidate for the development of PSMA-specific dual-imaging agents.     

Linear elastic stress intensity factors for cracks in nuclear pressure vessel nozzles under pressure and temperature loading

Stress intensity factors for two different nozzle geometries and different crack sizes are evaluated for pressure and thermal loading utilising three-dimensional elastic finite element models.The results are compared to available experimental data and a procedure is proposed to estimate the maximum of the stress intensity factor for arbitrary crack size and loading conditions.     

Treatment of haemophilia with factor VIII inhibitor by giving isoagglutinin-free factor VIII concentrate (author's transl)

Two nine-year-old boys with haemophilia A and circulating inhibitor against factor VIII were given large doses of commercial AHG concentrates to control bleeding. But the isoagglutinins in the AHG concentrates caused haemolysis in both patients. When AHF (Immuno) from AB donors - a cryoprecipate without isoagglutinins - was used no further inhibitor activity was detectable, previously observed anaphylactoid reactions no longer occurred and usual doses of AHG were now sufficient to control bleeding.