Information flows amongst executives: their implications for systems development

Senior managers have tended to resist the incursion into their personal domain of computer systems meant for their use. Their main criticism is that technical solutions are being imposed on them without an adequate analysis of the problems at hand. This suggests that the way in which executives obtain and exchange information may not be adequately understood. With the help of a framework designed to identify top executives' networks of information flows, the study reported in this paper analysed the information practices of 16 executives from four organizations. The findings of the research indicated that executives use a combination of communication flows and information flows in a proportion which varies depending upon the context of their different activities. It also revealed that executives initiated information and communication flows of a different nature depending upon the role they play and the level of those with whom they deal within the organization. The results of the study suggest that very specific approaches are needed when identifying executives' needs in terms of developing systems aimed at supporting top managers' strategic activities.     

A recognition network model-based approach to dynamic image understanding

In this paper, we present definitions for a dynamic knowledge-based image understanding system. From a sequence of grey level images, the system produces a flow of image interpretations. We use a semantic network to represent the knowledge embodied in the system. Dynamic representation is achieved by ahypotheses network. This network is a graph in which nodes represent information and arcs relations. A control strategy performs a continuous update of this network. The originality of our work lies in the control strategy: it includes astructure tracking phase, using the representation structure obtained from previous images to reduce the computational complexity of understanding processes. We demonstrate that in our case the computational complexity, which is exponential if we only use a purely data-driven bottom-up scheme, is polynomial when using the hypotheses tracking mechanism. This is to say that gain improvement in computation time is a major reason for dynamic understanding. The proposed system is implemented; experimental results of road mark detection and tracking are given.     

Thiol‐mediated degradation of DNA adsorbed on a colloidal gold surface

When [³²P]‐labeled DNA is adsorbed on colloidal gold from a 130 mmol dm^?3 solution of KH₂PO₄, it can subsequently be eluted with cold DNA without undergoing detectable degradation. Similarly, DNA can be incubated in solution in the presence or absence of colloidal gold with high concentrations of β‐mercaptoethanol or hexane‐1‐thiol without significant degradation. However, when adsorbed DNA is eluted from gold with solutions of one of the thiols, it is recovered as a mixture of mononucleotides and short oligomers. The extent of degradation increases with increasing concentration of the thiol and with increasing elution temperature. Our results emphasize that in designing protocols involving DNA adsorbed on gold surfaces, it is important to avoid allowing the DNA to come into contact with even moderate concentrations of thiols. © 2003 Society of Chemical Industry     

<Emphasis Type="Italic">Sphagnum</Emphasis> Species Modulate their Phenolic Profiles and Mycorrhizal Colonization of Surrounding <Emphasis Type="Italic">Andromeda polifolia</Emphasis> along Peatland Microhabitats

Sphagnum mosses mediate long-term carbon accumulation in peatlands. Given their functional role as keystone species, it is important to consider their responses to ecological gradients and environmental changes through the production of phenolics. We compared the extent to which Sphagnum phenolic production was dependent on species, microhabitats and season, and how surrounding dwarf shrubs responded to Sphagnum phenolics. We evaluated the phenolic profiles of aqueous extracts of Sphagnum fallax and Sphagnum magellanicum over a 6-month period in two microhabitats (wet lawns versus dry hummocks) in a French peatland. Phenolic profiles of water-soluble extracts were measured by UHPLC-QTOF-MS. Andromeda polifolia mycorrhizal colonization was quantified by assessing the intensity of global root cortex colonization. Phenolic profiles of both Sphagnum mosses were species-, season- and microhabitat- dependant. Sphagnum-derived acids were the phenolics mostly recovered; relative quantities were 2.5-fold higher in S. fallax than in S. magellanicum. Microtopography and vascular plant cover strongly influenced phenolic profiles, especially for minor metabolites present in low abundance. Higher mycorrhizal colonization of A. polifolia was found in lawns as compared to hummocks. Mycorrhizal abundance, in contrast to environmental parameters, was correlated with production of minor phenolics in S. fallax. Our results highlight the close interaction between mycorrhizae such as those colonizing A. polifolia and the release of Sphagnum phenolic metabolites and suggest that Sphagnum-derived acids and minor phenolics play different roles in this interaction. This work provides new insight into the ecological role of Sphagnum phenolics by proposing a strong association with mycorrhizal colonization of shrubs.