Bringing a Time–Depth Perspective to Collective Animal Behaviour

The field of collective animal behaviour examines how relatively simple, local interactions between individuals in groups combine to produce global-level outcomes. Existing mathematical models and empirical work have identified candidate mechanisms for numerous collective phenomena but have typically focused on one-off or short-term performance. We argue that feedback between collective performance and learning – giving the former the capacity to become an adaptive, and potentially cumulative, process – is a currently poorly explored but crucial mechanism in understanding collective systems. We synthesise material ranging from swarm intelligence in social insects through collective movements in vertebrates to collective decision making in animal and human groups, to propose avenues for future research to identify the potential for changes in these systems to accumulate over time

Comparative analysis of the lambda-interferons IL-28A and IL-29 regarding their transcriptome and their antiviral properties against hepatitis C virus.

Specific differences in signaling and antiviral properties between the different Lambda-interferons, a novel group of interferons composed of IL-28A, IL-28B and IL-29, are currently unknown. This is the first study comparatively investigating the transcriptome and the antiviral properties of the Lambda-interferons IL-28A and IL-29. Expression studies were performed by microarray analysis, quantitative PCR (qPCR), reporter gene assays and immunoluminometric assays. Signaling was analyzed by Western blot. HCV replication was measured in Huh-7 cells expressing subgenomic HCV replicon. All hepatic cell lines investigated as well as primary hepatocytes expressed both IFN-λ receptor subunits IL-10R2 and IFN-λR1. Both, IL-28A and IL-29 activated STAT1 signaling. As revealed by microarray analysis, similar genes were induced by both cytokines in Huh-7 cells (IL-28A: 117 genes; IL-29: 111 genes), many of them playing a role in antiviral immunity. However, only IL-28A was able to significantly down-regulate gene expression (n = 272 down-regulated genes). Both cytokines significantly decreased HCV replication in Huh-7 cells. In comparison to liver biopsies of patients with non-viral liver disease, liver biopsies of patients with HCV showed significantly increased mRNA expression of IL-28A and IL-29. Moreover, IL-28A serum protein levels were elevated in HCV patients. In a murine model of viral hepatitis, IL-28 expression was significantly increased. IL-28A and IL-29 are up-regulated in HCV patients and are similarly effective in inducing antiviral genes and inhibiting HCV replication. In contrast to IL-29, IL-28A is a potent gene repressor. Both IFN-λs may have therapeutic potential in the treatment of chronic HCV

Completion of Hepatitis C Virus Replication Cycle in Heterokaryons Excludes Dominant Restrictions in Human Non-liver and Mouse Liver Cell Lines

Hepatitis C virus (HCV) is hepatotropic and only infects humans and chimpanzees. Consequently, an immunocompetent small animal model is lacking. The restricted tropism of HCV likely reflects specific host factor requirements. We investigated if dominant restriction factors expressed in non-liver or non-human cell lines inhibit HCV propagation thus rendering these cells non-permissive. To this end we explored if HCV completes its replication cycle in heterokaryons between human liver cell lines and non-permissive cell lines from human non-liver or mouse liver origin. Despite functional viral pattern recognition pathways and responsiveness to interferon, virus production was observed in all fused cells and was only ablated when cells were treated with exogenous interferon. These results exclude that constitutive or virus-induced expression of dominant restriction factors prevents propagation of HCV in these cell types, which has important implications for HCV tissue and species tropism. In turn, these data strongly advocate transgenic approaches of crucial human HCV cofactors to establish an immunocompetent small animal model

Learning Spatio-Temporal Patterns for Predicting Object Behaviour

Rule-based systems employed to model complex object behaviours, do not necessarily provide a realistic portrayal of true behaviour. To capture the real characteristics in a specific environment, a better model may be learnt from observation. This paper presents a novel approach to learning long-term spatio-temporal patterns of objects in image sequences, using a neural network paradigm to predict future behaviour. The results demonstrate the application of our approach to the problem of predicting animal behaviour in response to a predator

Experiments in automatic ock control

Abstract. The Robot Sheepdog Project has developed a mobile robot that gathers a ock of ducks and manoeuvres them safely to a speci ed goal position. This is the rst example of a robot system that exploits and controls an animal's behaviour to achieve a useful task. A potential- eld model of ocking behaviour was constructed and used to invesigate methods for generalised ock control. One possible algorithm is described and demonstrated to work both in simulation and in the real world.

Using low-cost infrared detectors to monitor movement of pedestrians: initial findings.

Monitoring the movement of pedestrians in everyday environments is difficult, especially if accurate data are required. Typically, data pertaining to the origins and destinations of pedestrians as they move around a space can be obtained only by either locating many observers in the area that is under surveillance or analyzing closed-circuit television footage. The former is error prone and perturbs the space being analyzed; the latter is expensive in regard to the technology and time required. Technical advances in low-cost infrared detectors provide an opportunity to observe pedestrian spaces unobtrusively and determine individual pedestrian trajectories automatically. The underpinning detector technology is described, and the way arrays of such detectors can be used to monitor larger spaces is shown. An outline of the algorithm used to create complete trajectories as pedestrians move between detectors is presented. A series of experiments is described: pedestrians were asked to move in a set of defined patterns in a controlled environment. Initial results from these experiments are discussed. It was found that at Fruin Levels of Service A to C, 93% of pedestrian trajectories could be tracked; that count dropped to 79% at Level of Service

Experiments in Automatic Flock Control

The Robot Sheepdog Project has developed a mobile robot that gathers a flock of ducks and manoeuvres them safely to a specified goal position. This is the first example of a robot system that exploits and controls an animal's behaviour to achieve a useful task. A potential-field model of flocking behaviour was constructed and used to invesigate methods for generalised flock control. One possible algorithm is described and demonstrated to work both in simulation and in the real world