Comparison between ATSR2 stereo, MOS O2-A band and ground-based cloud top heights

A new method to retrieve cloud top heights stereoscopically using the dual-view facility of the Along Track Scanning Radiometer 2 (ATSR2) instrument is assessed. This assessment is performed through a comparison of the cloud top heights obtained from ATSR2 stereo and those derived from a 94-GHz radar, radiosonde profiles and independently from the Modular Optoelectronic Scanner (MOS) using the O2-A band. The data for this study were collected over the United Kingdom from September 1998 through March 1999. The results show that the accuracy of the ATSR2 stereo heights is generally as predicted on theoretical grounds, with the errors in the 1.6 μm and 0.65 μm stereo heights rarely exceeding 2 km. Case study periods with disagreements between the ATSR2 heights and the ground-based retrievals are often due to the lack of precise match-ups between the ground-based and satellite scenes, while the MOS O2-A band is shown sometimes to miss the tops of high clouds. Evidence that the 11 μm channel is more sensitive to high clouds than originally thought is given and a future application of multi-spectral stereo cloud top heights is proposed.A new method to retrieve cloud top heights stereoscopically using the dual-view facility of the Along Track Scanning Radiometer 2 (ATSR2) instrument is assessed. This assessment is performed through a comparison of the cloud top heights obtained from ATSR2 stereo and those derived from a 94-GHz radar, radiosonde profiles and independently from the Modular Optoelectronic Scanner (MOS) using the O2-A band. The data for this study were collected over the United Kingdom from September 1998 through March 1999. The results show that the accuracy of the ATSR2 stereo heights is generally as predicted on theoretical grounds, with the errors in the 1.6 μm and 0.65 μm stereo heights rarely exceeding 2 km. Case study periods with disagreements between the ATSR2 heights and the ground-based retrievals are often due to the lack of precise match-ups between the ground-based and satellite scenes, while the MOS O2-A band is shown sometimes to miss the tops of high clouds. Evidence that the 11 μm channel is more sensitive to high clouds than originally thought is given and a future application of multi-spectral stereo cloud top heights is proposed

Animal emergence during Snowball Earths by thermosynthesis in submarine hydrothermal vents

Darwin already commented on the lateness in the fossil record of the emergence of the animals, calling it a valid argument against his theory of evolution^1^. This emergence of the animals (metazoans: multicellular animals) has therefore attracted much attention^2-5^. Two decades ago it was reported that extensive global glaciations (Snowball Earths) preceded the emergence^6-7^. Here we causally relate the emergence and the glaciations by invoking benthic sessile^8-11^ thermosynthesizing^12-13^ protists that gained free energy as ATP while oscillating in the thermal gradient between a submarine hydrothermal vent^14^ and the ice-covered ocean. During a global glaciation their size increased from microscopic to macroscopic due to the selective advantage of a larger span of the thermal gradient. At the glaciation's end the ATP-generating mechanisms reversed and used ATP to sustain movement. Lastly, by functioning as animal organs, these protists then through symbiogenesis^15-17^ brought forth the first animals. This simple and straightforward scenario for the emergence of animals accounts for their large organ and organism size and their use of ATP, embryo and epigenetic control of development. The scenario is extended to a general model for the emergence of biological movement^18^. The presented hypothesis is testable by collecting organisms near today's submarine hydrothermal vents and studying their behaviour in the laboratory in easily constructed thermal gradients

A Multifunctional Processing Board for the Fast Track Trigger of the H1 Experiment

The electron-proton collider HERA is being upgraded to provide higher luminosity from the end of the year 2001. In order to enhance the selectivity on exclusive processes a Fast Track Trigger (FTT) with high momentum resolution is being built for the H1 Collaboration. The FTT will perform a 3-dimensional reconstruction of curved tracks in a magnetic field of 1.1 Tesla down to 100 MeV in transverse momentum. It is able to reconstruct up to 48 tracks within 23 mus in a high track multiplicity environment. The FTT consists of two hardware levels L1, L2 and a third software level. Analog signals of 450 wires are digitized at the first level stage followed by a quick lookup of valid track segment patterns. For the main processing tasks at the second level such as linking, fitting and deciding, a multifunctional processing board has been developed by the ETH Zurich in collaboration with Supercomputing Systems (Zurich). It integrates a high-density FPGA (Altera APEX 20K600E) and four floating point DSPs (Texas Instruments TMS320C6701). This presentation will mainly concentrate on second trigger level hardware aspects and on the implementation of the algorithms used for linking and fitting. Emphasis is especially put on the integrated CAM (content addressable memory) functionality of the FPGA, which is ideally suited for implementing fast search tasks like track segment linking.Comment: 6 pages, 4 figures, submitted to TN

Piezoelectric transducer

Transducer consists of a hybrid thin film and a piezoelectric transistor that acts as a stress-sensitive device with built-in gain. It provides a stress/strain transducer that incorporates a signal amplification stage and sensor in a single package

Hyposplenism in gastro-intestinal disease

The hazards of living without a spleen were recognised by the paediatricians in the early 1960’s when they focussed attention on the syndrome of fulminant sepsis, often due to pneumococcal infection, occurring in young children within the first two years of splenectomy. The danger of post-splenectomy sepsis (PSS) extends into adult life and splenectomised patients remain at risk 10, 20 and even 30 years after the operation. Problems following splenectomy may just be the tip of the iceberg. It is clear that many other diseases are associated with impaired splenic function in the presence of intact spleens.peer-reviewe

Regularized adaptive long autoregressive spectral analysis

This paper is devoted to adaptive long autoregressive spectral analysis when (i) very few data are available, (ii) information does exist beforehand concerning the spectral smoothness and time continuity of the analyzed signals. The contribution is founded on two papers by Kitagawa and Gersch. The first one deals with spectral smoothness, in the regularization framework, while the second one is devoted to time continuity, in the Kalman formalism. The present paper proposes an original synthesis of the two contributions: a new regularized criterion is introduced that takes both information into account. The criterion is efficiently optimized by a Kalman smoother. One of the major features of the method is that it is entirely unsupervised: the problem of automatically adjusting the hyperparameters that balance data-based versus prior-based information is solved by maximum likelihood. The improvement is quantified in the field of meteorological radar