Issues in a Mobile Agent-based Multimedia Retrieval Scenario

Abstract. Mobile agents traverse the Internet, often on behalf of their users. Intelligent search agents access dynamic information in heterogeneous environments. The legal implications of the use of agents in such situations are not fully understood. In this paper a scenario in which a mobile agent searches a multimedia database on behalf of its user, is used to illustrate the legal and technical issues involved. Requirements related to identity management, integrity, traceability and availability are identified and discussed in the context of existing technology.

Purification and spectroscopic characterization of photosystem II reaction center complexes isolated with or without Triton X-100.

The pigment composition of the isolated photosystem II reaction center complex in its most stable and pure form currently is a matter of considerable debate. In this contribution, we present a new method based on a combination of gel filtration chromatography and diode array detection to analyze the composition of photosystem II reaction center preparations. We show that the method is very sensitive for the detection of contaminants such as the core antenna protein CP47, pigment-free and denatured reaction center proteins, and unbound chlorophyll and pheophytin molecules. We also present a method by which the photosystem II reaction center complex is highly purified without using Triton X-100, and we show that in this preparation the contamination with CP47 is less than 0.1%. The results strongly indicate that the photosystem II reaction center complex in its most stable and pure form binds six chlorophyll a, two pheophytin a, and two β-carotene molecules and that the main effect of Triton X-100 is the extraction of β-carotene from the complex. Analysis of 4 K absorption and emission spectra indicates that the spectroscopic properties of this preparation are similar to those obtained by a short Triton X-100 treatment. In contrast, preparations obtained by long Triton X-100 treatment show decreased absorption of the shoulder at 684 nm in the 4 K absorption spectrum and an increased number of pigments that trap excitation energy at very low temperatures. We conclude that the 684 nm shoulder in the 4 K absorption spectrum should at least in part be attributed to the primary electron donor of photosystem II

Evolution of reproductive isolation of spodoptera frugiperda

Spodoptera frugiperda, the fall armyworm, is a noctuid moth occurring in North and South America. In this species, two host strains have been identified in the late 1980s (Pashley et al. 1985; Pashley 1986), a so-called corn-strain and a so-called rice-strain. The two strains differ in mitochondrial DNA sequences in the cytochrome oxidase I (COI) and NADH dehydrogenase 1(ND1) genes. There are also strain-specific amplified fragment length polymorphisms (AFLP), restriction length fragment polymorphisms (RFLP), a so-called Frugiperda Rice (FR) repetitive nuclear DNA sequence, present in high copy number in the rice-strain and mostly lower copy number in the corn-strain and nucleotide polymorphisms within the triose phosphate isomerase gene (Tpi). Recently, sex pheromone differences have been found between populations of the two strains. However, these differences were not consistent between the studies, suggesting that geographic variation may be confounded with strain-specific variation, or that pheromones may vary within strains as well. The relative importance of the pheromone differences between the two strains still needs to be established, i.e. are males of the two strains differentially attracted to the different pheromone blends. Since other physiological, developmental, and behavioral differences have been found between the strains, in this overview we integrate strain-specific variation in sexual communication with other possible pre- and postmating barriers that are likely involved in the differentiation between the two strains.Fil: Groot, Astrid T.. University of Amsterdam; Países BajosFil: Unbehend, Melanie. Instituto Max Planck Institut für Chemische Okologie; AlemaniaFil: Hänniger, Sabine. Instituto Max Planck Institut für Chemische Okologie; AlemaniaFil: Juárez, María Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - Tucumán. Unidad Ejecutora Lillo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - Tucumán. Unidad Ejecutora Lillo; ArgentinaFil: Kost, Silvia. Instituto Max Planck Institut für Chemische Okologie; AlemaniaFil: Heckel, David G.. Instituto Max Planck Institut für Chemische Okologie; Alemani

Comparison of muscle strength, sprint power and aerobic capacity in adults with and without cerebral palsy

Objective: To compare: (i) muscle strength, sprint power and maximal aerobic capacity; and (ii) the correlations between these variables in adults with and without cerebral palsy. Design: Cross-sectional study. Subjects: Twenty adults with and 24 without cerebral palsy. Methods: Isometric and isokinetic knee extension strength, sprint power (mean power over the 30s (P30)), peak aerobic power output (POpeak) and oxygen uptake (VO2peak) were determined. Regression analysis was used to investigate correlations between parameters. Results: Adults with cerebral palsy had significantly lower strength (53-69%) and P30 (67%) than adults without cerebral palsy, but similar POpeak and VO2peak. In adults without cerebral palsy the only significant correlations, albeit weak, were between P30 and isometric (R-2=0.34) or isokinetic strength (R-2=0.20), as well as the correlation between P30 and VOpeak (R-2=0.26) or POpeak (R-2=0.36). Stronger correlations were found in the group with cerebral palsy between P30 and isometric (R-2=0.52) and isokinetic strength (R-2=0.71) and between P30 and VOpeak (R-2=0.75) or POpeak (R-2=0.94). Conclusion: In contrast to aerobic capacity, strength and P30 are reduced in (active) people with cerebral palsy. Stronger correlations were found between strength, P30 and POpeak in adults with cerebral palsy. Therefore, muscle strength may be the limiting factor in adults with cerebral palsy for activities involving the lower extremities, such as cycling

Evaluation of non-chemical seed treatment methods for the control of Alternaria dauci and A. radicina on carrot seeds

The current study was initiated to evaluate the efficacy of physical methods (hot water, aerated steam, electron treatment) and agents of natural origin (resistance inducers, plant derived products, micro-organisms) as seed treatments of carrots for control of Alternaria dauci and A. radicina. Control of both Alternaria species by seed treatment with the resistance inducers was generally poor. Results were also not satisfactory with most of the formulated commercial micro-organism preparations. Based on the average of five field trials, one of these, BA 2552 (Pseudomonas chlororaphis), provided a low but significant increase in plant stand. Among the experimental micro-organisms, the best results were obtained with Pseudomonas sp. strain MF 416 and Clonostachys rosea strain IK726. A similar level of efficacy was provided by seed treatment with an emulsion (1%) of thyme oil in water. Good and consistent control was generally achieved with the physical methods aerated steam, hot water and electron treatment. Aerated steam treatment was, apart from the thiram-containing chemical standard, the best single treatment, and its performance may at least partially be due to extensive pre-testing, resulting in dosages optimally adapted to the respective seed lot. In some of the experiments the effect of the hot water treatment, which was tested at a fixed, not specifically adapted dosage, was significantly improved when combined with a Pseudomonas sp. MF 416 or C. rosea IK726 treatment. The results are discussed in relation to the outcome of experiments in which the same seed treatment methods and agents were tested in other seed-borne vegetable pathosystems

STOVE: Seed treatments for organic vegetable production

The aim of the EU-financed research project „STOVE“ (Seed Treatments for Organic Vegetable Production) is to evaluate different methods potentially suited for seed treatment of vegetables in organic farming regarding their efficacy, to optimise these methods, and where feasible to combine them with each other. Scientists from seven European research institutions and a producer of organic vegetable seeds carry out the project