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Abstract. The Response Time Variability Problem (RTVP) is an NP-hard combinatorial scheduling problem that has recently appeared in the literature. The RTVP has a wide range of real-life applications such as in the automobile industry, when models to be produced on a mixed-model assembly line have to be sequenced. The RTVP occurs whenever products, clients or jobs need to be sequenced so as to minimize variability in the time between the instants at which they receive the necessary resources. The field of Artificial Intelligence has provided us with efficient tools such as metaheuristic techniques for solving complex combinatorial scheduling problems. In a previous study, three metaheuristic algorithms (a multi-start, a GRAP and a PSO algorithm) were proposed to solve the RTVP. These three metaheuristic algorithms have been most efficient, until now, in solving non-small instances of the RTVP. We propose solving the RTVP by means of the electromagnetism-like mechanism (EM) metaheuristic algorithm. The EM algorithm is based on an analogy with the attraction-repulsion mechanism of the electromagnetism theory, where solutions are moved according to their associated charges. In this paper we compare the proposed EM metaheuristic procedure with the three metaheuristic algorithms previously mentioned and show that, on average, the EM procedure improves on the obtained results.

This paper describes the Heterodyne Instrument for the Far-Infrared (HIFI), to be launched onboard of ESA's Herschel Space Observatory, by 2008. It includes the first results from the instrument level tests. The instrument is designed to be electronically tuneable over a wide and continuous frequency range in the Far Infrared, with velocity resolutions better than 0.1 km/s with a high sensitivity. This will enable detailed investigations of a wide variety of astronomical sources, ranging from solar system objects, star formation regions to nuclei of galaxies. The instrument comprises 5 frequency bands covering 480-1150 GHz with SIS mixers and a sixth dual frequency band, for the 1410-1910 GHz range, with Hot Electron Bolometer Mixers (HEB). The Local Oscillator (LO) subsystem consists of a dedicated Ka-band synthesizer followed by 7 times 2 chains of frequency multipliers, 2 chains for each frequency band. A pair of Auto-Correlators and a pair of Acousto-Optic spectrometers process the two IF signals from the dual-polarization front-ends to provide instantaneous frequency coverage of 4 GHz, with a set of resolutions (140 kHz to 1 MHz), better than < 0.1 km/s. After a successful qualification program, the flight instrument was delivered and entered the testing phase at satellite level. We will also report on the pre-flight test and calibration results together with the expected in-flight performance.

The cover picture shows a constrained peptidomimetic of the Asn-Pro-Asn-Ala-Asn motif that is found in the major surface protein of Plasmodium falciparum sporozoites. The mimetic (bottom) is coupled through a succinate linker to a regioisomer of phosphatidylethanolamine to afford a conjugate (top; the loop on the left represents the mimetic) that can be incorporated into immunopotentiating reconstituted influenza virosomes (IRIVs). When presented to the immune system in this form, the mimetic elicits an efficient parasite cross-reactive antibody response. The background shows immunofluorescence labeling of P. falciparum sporozoites (bright green rods). IRIVs are a form of antigen delivery that is already licensed for human clinical use so this approach may have great potential for the design and delivery of synthetic vaccines. For more details, see the article by Robinson, Pluschke, and co-workers on p. 838 ff.