DAC-h3: A Proactive Robot Cognitive Architecture to Acquire and Express Knowledge About the World and the Self

This paper introduces a cognitive architecture for a humanoid robot to engage in a proactive, mixed-initiative exploration and manipulation of its environment, where the initiative can originate from both the human and the robot. The framework, based on a biologically-grounded theory of the brain and mind, integrates a reactive interaction engine, a number of state-of-the art perceptual and motor learning algorithms, as well as planning abilities and an autobiographical memory. The architecture as a whole drives the robot behavior to solve the symbol grounding problem, acquire language capabilities, execute goal-oriented behavior, and express a verbal narrative of its own experience in the world. We validate our approach in human-robot interaction experiments with the iCub humanoid robot, showing that the proposed cognitive architecture can be applied in real time within a realistic scenario and that it can be used with naive users

The dominating macromolecular complex of human gallbladder bile

The solutes of human gall bladder bile appear to exist mainly in the form of a complex macromolecule, formed around a nucleus of lipoprotein. The existence of this macromolecule was demonstrated by paper electrophoresis1, free electrophoresis and ultracentrifuge experiments. The molecular weight of the compound was found to be of the magnitude of 26,000. Evidence was obtained that the complex has no completely constant composition. The main molecular constitution per molecule of the complex was calculated as: 0.57 mol. bilirubin, 3.4 mol. cholesterol, 39.8 mol. desoxycholic acid and 7.3 mol. lecithins, probably grouped around one or more molecules of a polypeptide with a molecular weight below 10, 000. As this complex is the main macromolecular constituent of gall bladder bile and contains all the bilirubin present, and about 80% of the cholesterol, it must be involved in stabilising the gall bladder bile and thus be related to gallstone formation. The concentration of the complex was found to be lower, the more inflammatory signs were present in the gall bladder. The properties of the complex, such as stability, resistance to extraction procedures, precipitation and staining properties, were studied. Finally, the occurrence of the bili-lipoprotein was studied in 360 bile samples, 64 from gall bladder bile, all obtained by puncture of the gall bladder during surgery, and 296 samples of fistula bile and samples obtained by puncture of the hepatic duct during surgery. The lipoprotein complex, always abundantly present in gall bladder bile if no inflammation of the gall bladder exists, was absent in 2/3 of the fistula bile samples. In fistula bile it is never found in concentrations as great as in gall bladder bile. Artificial concentration of fistula bile that contains an appreciable amount of the complex seldom gave a product that was equal to or closely resembling gall bladder bile. These and other facts suggest production of lipoprotein within the gall bladder, and in minor quantities under certain conditions by the walls of the bile passages

Further investigations on the macromolecular complex in human bile

The formation of complexes in human bile was further studied by the preparation of various synthetic complexes and extracts. These were compared for a number of properties with the natural complex of human gall bladder bile. It appeared that protein is probably and bilirubin quite definitely a constituent of the natural complex. Small quantities of the complex or related substances could be detected in fistula bile. Complex formation begins in the fistula bile, but in the gall bladder the conditions for complex formation are optimal. The phenomena cannot be explained by concentration of the hepatic bile alone

The eukaryotic genome: a system regulated at different hierarchical levels.

Eukaryotic gene expression can be viewed within a conceptual framework in which regulatory mechanisms are integrated at three hierarchical levels. The first is the sequence level, i.e. the linear organization of transcription units and regulatory sequences. Here, developmentally coregulated genes seem to be organized in clusters in the genome, which constitute individual functional units. The second is the chromatin level, which allows switching between different functional states. Switching between a state that suppresses transcription and one that is permissive for gene activity probably occurs at the level of the gene cluster, involving changes in chromatin structure that are controlled by the interplay between histone modification, DNA methylation, and a variety of repressive and activating mechanisms. This regulatory level is combined with control mechanisms that switch individual genes in the cluster on and off, depending on the properties of the promoter. The third level is the nuclear level, which includes the dynamic 3D spatial organization of the genome inside the cell nucleus. The nucleus is structurally and functionally compartmentalized and epigenetic regulation of gene expression may involve repositioning of loci in the nucleus through changes in large-scale chromatin structure

Further investigations on the macromolecular complex in human bile

The formation of complexes in human bile was further studied by the preparation of various synthetic complexes and extracts. These were compared for a number of properties with the natural complex of human gall bladder bile. It appeared that protein is probably and bilirubin quite definitely a constituent of the natural complex. Small quantities of the complex or related substances could be detected in fistula bile. Complex formation begins in the fistula bile, but in the gall bladder the conditions for complex formation are optimal. The phenomena cannot be explained by concentration of the hepatic bile alone