Interactive Concept Acquisition for Embodied Artificial Agents

An important capacity that is still lacking in intelligent systems such as robots, is the ability to use concepts in a human-like manner. Indeed, the use of concepts has been recognised as being fundamental to a wide range of cognitive skills, including classification, reasoning and memory. Intricately intertwined with language, concepts are at the core of human cognition; but despite a large body or research, their functioning is as of yet not well understood. Nevertheless it remains clear that if intelligent systems are to achieve a level of cognition comparable to humans, they will have to posses the ability to deal with the fundamental role that concepts play in cognition. A promising manner in which conceptual knowledge can be acquired by an intelligent system is through ongoing, incremental development. In this view, a system is situated in the world and gradually acquires skills and knowledge through interaction with its social and physical environment. Important in this regard is the notion that cognition is embodied. As such, both the physical body and the environment shape the manner in which cognition, including the learning and use of concepts, operates. Through active partaking in the interaction, an intelligent system might influence its learning experience as to be more effective. This work presents experiments which illustrate how these notions of interaction and embodiment can influence the learning process of artificial systems. It shows how an artificial agent can benefit from interactive learning. Rather than passively absorbing knowledge, the system actively partakes in its learning experience, yielding improved learning. Next, the influence of embodiment on perception is further explored in a case study concerning colour perception, which results in an alternative explanation for the question of why human colour experience is very similar amongst individuals despite physiological differences. Finally experiments, in which an artificial agent is embodied in a novel robot that is tailored for human-robot interaction, illustrate how active strategies are also beneficial in an HRI setting in which the robot learns from a human teacher

Effect of organically and conventionally produced diets on jejunal gene expression in chickens

Using a nutrigenomics approach we studied the response of second-generation chickens at a transcriptional level to organically grown feed ingredients compared with conventionally grown feed ingredients. Both diets consisted of the same amounts of ingredients, the only difference was the production method. Gene expression was analysed in jejuni using whole genome chicken cDNA arrays. After analysis, forty-nine genes were found to be differentially regulated between chickens fed on the different diets, independent of their genetic background. Of these forty-nine genes, seven genes were involved in cholesterol biosynthesis. Genes involved in cholesterol biosynthesis were higher expressed in jejuni from organically fed birds. Other genes found to be regulated were involved in immunological processes, such as B-G protein (part of chicken major histocompatibility complex), chemokine ah221, and the immunoglobulin heavy chain. Using quantitative PCR the effect of genetic background on the differential expression of genes was studied. Differences in gene expression existed between animals fed different diets as well as between different chicken lines. This indicated that diet and genetic background influence the transcriptional response of the jejunum. This is the first time that significant differences in gene expression were shown between animals on diets with organically or conventionally produced ingredient

ArgR is an essential local transcriptional regulator of the arcABC-operon in Streptococcus suis and crucial for biological fitness in acidic environment

Streptococcus suis is one of the most important pathogens in pigs and can also cause severe infections in humans. Despite its clinical relevance very little is known about the factors contributing to its virulence. Recently, we identified a new putative virulence factor in Streptococcus suis, the arginine deiminase system (ADS), an arginine catabolic enzyme system encoded by the arcABC-operon, which enables Streptococcus suis to survive in acidic environment. In this study, we focused on ArgR, an ADS associated regulator belonging to the ArgR/AhrC arginine repressor family. Using an argR knock-out strain we could show that ArgR is essential for arcABC-operon expression and necessary for the biological fitness of Streptococcus suis. By cDNA expression microarray analyses and quantitative real time RT-PCR we found that the arcABC-operon is the only gene cluster regulated by ArgR, which is in contrast to many other bacteria. Reporter gene analysis with gfp under the control of the arcABC promoter demonstrated that ArgR is able to activate the arcABC promoter. Electrophoretic mobility shift assays with fragments of the arcABC promoter and recombinant ArgR, and chromatin immunoprecipitation with antibodies directed against ArgR revealed that ArgR interacts with the arcABC promoter in vitro and in vivo by binding to a region from -147 to 72 bp upstream of the transcriptional start point. Overall our results show that in Streptococcus suis ArgR is an essential, system specific transcriptional regulator of the ADS directly interacting with the arcABC promoter in vivo

From Penguins to Parakeets: a Developmental Approach to Modelling Conceptual Prototypes

The use of concepts is a fundamental capacity underlying complex, human-level cognition. A number of theories have explored the means of concept representation and their links to lower-level features, with one notable example being the Conceptual Spaces theory. While these provide an account for such essential functional processes as prototypes and typicality, it is not entirely clear how these aspects of human cognition can arise in a system undergoing continuous development - postulated to be a necessity from the developmental systems perspective. This paper seeks to establish the foundation of an approach to this question by showing that a distributed, associative and continuous development mechanism, founded on principles of biological memory, can achieve classification performance comparable to the Conceptual Spaces model. We show how qualitatively similar prototypes are formed by both systems when exposed to the same dataset, which illustrates how both models can account for the development of conceptual primitives

Resistance of the body louse( Pediculus humanus corporis de G) to DDT powders

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