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Background The Symmetry Bypass System Aortic Connector (St Jude Medical, Inc) is a novel device for the construction of sutureless proximal anastomoses. The connector allows attachment of saphenous vein grafts to the aorta without requiring aortic clamping. We report our initial clinical experience with this device. Methods In a 2-month period from May to July 2001, a total of 139 consecutive proximal anastomoses were performed in 67 patients using the connector. All procedures were performed on a beating heart without cardiopulmonary bypass or any aortic clamping. Intraoperative variables and postoperative results were prospectively collected and retrospectively analyzed. Results Of 139 consecutive proximal anastomoses 138 (99.3%) were successfully completed with the device. One anastomosis required suture revision because of misdeployment. Six anastomoses (4.3%) required an additional suture for leak. Predeployment problems included connector loading/preparation malfunction in 10 grafts (7.2%), five because of human error and five technical failure. There was no operative mortality, perioperative myocardial infarction, or stroke. Vessels bypassed included the circumflex system (n = 59), right coronary artery and branches (n = 48), diagonal branch (n = 26), and left anterior descending coronary artery (n = 6). At a mean follow-up of 7 months, survival was 94.1% and survival free of major adverse cardiac and cerebrovascular events (MACCE) was 88.1%. Conclusions Initial clinical experience with a sutureless proximal saphenous vein graft to aorta anastomosis performed with a mechanical connector demonstrates safety, reliability, and ease of use. Surmounting a brief learning curve improves the subtleties of device loading and deployment. Further benefits will be determined in an ongoing randomized study.

The theory of quantum electrodynamics has presented a complete calculation of the energy levels of positronium (Ps, e + e − ) up to the order R ∞ α 4 . The annihilation rates for para -Ps (1 1 S 0 ) and ortho -Ps (1 1 S 1 ) are completely known up to the order R ∞ α 5 and R ∞ α 6 , respectively. The present experimental uncertainty for spectroscopic results is 5–100 times larger than the theoretical uncertainty. For the annihilation rates the experimental situation is even worse. The theoretical predictions have presently reached a level of precision which is a challenge to experimentalists! The experimental uncertainty for the fine- and hyperfine transitions in the Ps atom is determined by the natural line width. An improvement is only possible with better statistics, i.e. higher positron intensities. For the annihilation rate of ortho -Ps there exist controversial measurements. Here completely new experiments are necessary which differ from the old measurements by possible systematic errors. All new proposals need high positron intensities which can be conveniently produced by bremsstrahlung and pair conversion in the beam dump of medium energy electron accelerators.

Several business sectors have identified the potential benefits of a landscape/urban assessment based upon the objective appraisal of the interaction of the cultural and natural landscapes. This paper describes a recently approved project (PLAINS) funded by DGXII of the European Union under the Framework IV Environment and Climate Programme. The aim of this project is to identify the benefits of introducing satellite Earth Observation data into the landscape assessment process and to develop a decision support system that will provide for landscape/urban classification tuned to satisfy specific customer requirements. The system will also allow the exploration of impact assessment (‘what if’) scenarios. The project involves three different business sectors who have inherently similar requirements in landscape assessment. The ‘customer’ organisations involved in the project cover the sectors: regional planning authorities, Estate Agents and tourism. In all, there are 13 partners involved in the project from five countries (UK, Denmark, Germany, Italy, Poland). The initial development of the system will use test sites in the counties of Hereford and Worcester in the UK, with subsequent validation being carried out at sites in Italy (Province of Savona), Germany and Poland.

To prepare dense bunches of lead ions for the LHC it has been proposed to accumulate the 4.2 MeV/u linac beam in a storage ring with electron cooling. A series of experiments is being performed in the low-energy ring LEAR to test this technique. First results were already reported at the Beam Crystallisation Workshop in Erice in November 1995. Two more recent runs to complement these investigations were concerned with: further study of the beam lifetime; the dependence of the cooling time on optical settings of the storage ring and on neutralization of the electron beam; and tests in view of multiturn injection. New results obtained in these two runs in December 1995 and in April 1996 will be discussed in this contribution.

This report presents results of experiments performed between 1994 and 1996 by a CERN/JINR collaboration, aimed to study the problem of the generation of intense electron beams whose space charge is neutralised by the residual gas ions. The problem is related to the development of electron cooling methods. The large space charge potential for high density electron beams is a significant drawback for the cooling process. In order to reduce this effect, an electron beam neutralisation system has been implemented on the LEAR cooler and the JINR test bench. In this paper we briefly discuss the physics of the neutralisation process, technological aspects of neutralisation, the measurement techniques and the results.

A large space-charge is detrimental to the cooling process of a dense beam. Generation of a neutralised electron beam is restricted by beam-drift instability. To suppress this instability, active methods are used: a kicker with a transverse electric field (shaker) and longitudinal electrodes placed in the vacuum chamber and in the gun region expel secondary electrons. Results of experiments dedicated to the development of beam stabilisation on the JINR test bench and in the electron cooling system at LEAR are discussed.

An important aspect of the low-energy physics programme at LEAR is the use of electron cooling for phase-space compression of the circulating ion beam [1–3]. In order to improve the reliability of the cooling device, a new electron beam collector has been developed in a collaboration between CERN and CAPT (Centre of Applied Physics and Technology) Lipetsk. The collector is designed to recuperate 3.3 A of 35 keV electrons with an efficiency better than 99.99%. It was constructed at the INP (Institute of Nuclear Physics) Novosibirsk workshop in accordance with a design produced by CAPT and the electron cooling team at CERN. The vacuum and electrical test of the collector were performed at Lipetsk. The device is now installed at LEAR and has undergone first reception tests in the machine.

A 14 MeV c.w. electron accelerator is used for pair production in a tungsten target of 0.7 radiation lengths thickness. A small fraction of the positrons is thermalized and diffuses out of the surface ofsurface of a well annealed tungsten foil coated with MgO which is positioned immediately behind the target. The slow positrons are extracted from the target region and magnetically guided over a distance of 10 m onto a channelplate multiplier at the end of an S-shaped solenoid. The positrons are identified by their annihilation radiation using two NaI-detectors. The intensity of the slow positrons is proportional to the accelerator electron beam current. The maximum intensity of 2.2 × 105 slow positrons per second reaching thedetector at an accelerator current of 15 μA was limited by the power deposited in the uncooled target. The energy of the positrons is concentrated in a small region at about 1 eV and clearly demonstrates the emission of thermal positrons.