Lysophosphatidic acid (LPA) is a lipid mediator with a wide variety of biological actions, particularly as an inducer of cell proliferation, migration and survival. LPA binds to specific G‐protein‐coupled receptors and thereby activates multiple signal transduction pathways, including those initiated by the small GTPases Ras, Rho, and Rac. LPA signaling has been implicated in such diverse processes as wound healing, brain development, vascular remodeling and tumor progression. Knowledge of precisely how and where LPA is produced has long proved elusive. Excitingly, (...) it has recently been discovered that LPA is generated from precursors by ‘autotaxin’, a once enigmatic exo‐phosphodiesterase implicated in tumor cell motility. Exogenous phospholipases D can also produce LPA, which may contribute to their toxicity. Here we review recent progress in our understanding of LPA bioactivity, signaling and synthesis. BioEssays 26:870–881, 2004. © 2004 Wiley Periodicals, Inc. (shrink)

Rapid developments in Artificial Intelligence are leading to an increasing human reliance on machine decision making. Even in collaborative efforts with Decision Support Systems (DSSs), where a human expert is expected to make the final decisions, it can be hard to keep the expert actively involved throughout the decision process. DSSs suggest their own solutions and thus invite passive decision making. To keep humans actively ‘on’ the decision-making loop and counter overreliance on machines, we propose a ‘reflection machine’ (RM). This (...) system asks users questions about their decision strategy and thereby prompts them to evaluate their own decisions critically. We discuss what forms RMs can take and present a proof-of-concept implementation of a RM that can produce feedback on users’ decisions in the medical and law domains. We show that the prototype requires very little domain knowledge to create reasonably intelligent critiquing questions. With this prototype, we demonstrate the technical feasibility to develop RMs and hope to pave the way for future research into their effectiveness and value. (shrink)

The explanatory gap refers to the lack of concepts for understanding “how it is that . . . a state of consciousness comes about as a result of irritating nervous tissue.” By assuming that there are colours in the outside world, Block needlessly widens this gap and Lycan and Kitcher simply fail to see the gap. When such assumptions are abandoned, an unnecessary and incomprehensible constraint disappears. It then becomes clear that the brain can use its own neural language for (...) representing aspects of the outside world. While this may not close the gap, it becomes clearer where we need new concepts. (shrink)

In the present article we argue that emotional interactions are not appropriately captured in present emotion research and theorizing. Emotional stimuli or antecedents are dynamic and change over time because they often interact and have a specific relationship with the subject. Earlier emotional interactions may, for example, intensify later emotional reactions to a specific person, or our anger reactions towards powerful or powerless others may differ considerably. Thus, we suggest that such social factors not only affect the intensity, but also (...) the nature of emotional experiences and expressions, and specifically the nature of the social movement (e.g., moving towards, away, or against). We discuss different processes that are implicated in the relation between the social environment and our emotions, describe how emotional expressions shape social behavior, and provide suggestions for incorporating the social dimension of emotion in future research. (shrink)