64,897 research outputs found

    Summation of visual and mechanosensory feedback in Drosophila flight control

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    The fruit fly Drosophila melanogaster relies on feedback from multiple sensory modalities to control flight maneuvers. Two sensory organs, the compound eyes and mechanosensory hindwings called halteres, are capable of encoding angular velocity of the body during flight. Although motor reflexes driven by the two modalities have been studied individually, little is known about how the two sensory feedback channels are integrated during flight. Using a specialized flight simulator we presented tethered flies with simultaneous visual and mechanosensory oscillations while measuring compensatory changes in stroke kinematics. By varying the relative amplitude, phase and axis of rotation of the visual and mechanical stimuli, we were able to determine the contribution of each sensory modality to the compensatory motor reflex. Our results show that over a wide range of experimental conditions sensory inputs from halteres and the visual system are combined in a weighted sum. Furthermore, the weighting structure places greater influence on feedback from the halteres than from the visual system

    Virtual Meeting Rooms: From Observation to Simulation

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    Virtual meeting rooms are used for simulation of real meeting behavior and can show how people behave, how they gesture, move their heads, bodies, their gaze behavior during conversations. They are used for visualising models of meeting behavior, and they can be used for the evaluation of these models. They are also used to show the effects of controlling certain parameters on the behavior and in experiments to see what the effect is on communication when various channels of information - speech, gaze, gesture, posture - are switched off or manipulated in other ways. The paper presents the various stages in the development of a virtual meeting room as well and illustrates its uses by presenting some results of experiments to see whether human judges can induce conversational roles in a virtual meeting situation when they only see the head movements of participants in the meeting

    Virtual Meeting Rooms: From Observation to Simulation

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    Much working time is spent in meetings and, as a consequence, meetings have become the subject of multidisciplinary research. Virtual Meeting Rooms (VMRs) are 3D virtual replicas of meeting rooms, where various modalities such as speech, gaze, distance, gestures and facial expressions can be controlled. This allows VMRs to be used to improve remote meeting participation, to visualize multimedia data and as an instrument for research into social interaction in meetings. This paper describes how these three uses can be realized in a VMR. We describe the process from observation through annotation to simulation and a model that describes the relations between the annotated features of verbal and non-verbal conversational behavior.\ud As an example of social perception research in the VMR, we describe an experiment to assess human observers’ accuracy for head orientation

    The Facebook Project - The Missing Box: The Racial Politics Behind the Facebook Interface

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    There is no race, ethnicity or nationality category available the default Facebook profile. This, combined with the fact that Facebook is a visually-driven website, suggests that Facebook serves to inadvertently or covertly perpetuate two racist or discriminatory norms: the colorblind mentality and racialized visual classification of others. This paper quickly traverses through a basic theory of identity that dictates that persons incur an on-going dialectic between individual and social identity, both on and offline. It contends that Facebook is an advantageous place to perform and portray one???s social identity and is largely visually-driven, therefore the interface is of paramount importance. Racial, ethnic, or national identity is of significance to many individuals and the lack of a place to express this is a form of discrimination. Such a category should be added to Facebook???s set of basic identity options. Guidelines for a successful implementation are provided.unpublishedis peer reviewe

    Testing the domain-general nature of monitoring in the spatial and verbal cognitive domains

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    While it is well-established that monitoring the environment for the occurrence of relevant events represents a key executive function, it is still unclear whether such a function is mediated by domain-general or domain-specific mechanisms. We investigated this issue by combining event-related potentials (ERPs) with a behavioral paradigm in which monitoring processes (non-monitoring vs. monitoring) and cognitive domains (spatial vs. verbal) were orthogonally manipulated in the same group of participants. They had to categorize 3-dimensional visually presented words on the basis of either spatial or verbal rules. In monitoring blocks, they additionally had to check whether the word displayed a specific spatial configuration or whether it contained a certain consonant. The behavioral results showed slower responses for both spatial and verbal monitoring trials compared to non-monitoring trials. The ERP results revealed that monitoring did not interact with domain, thus suggesting the involvement of common underlying mechanisms. Specifically, monitoring acted on lower-level perceptual processes (as expressed by an enhanced visual N1 wave and a sustained posterior negativity for monitoring trials) and on higher-level cognitive processes (involving larger positive modulations by monitoring trials over frontal and parietal scalp regions). The source reconstruction analysis of the ERP data confirmed that monitoring was associated with increased activity in visual areas and in right prefrontal and parietal regions (i.e., superior and inferior frontal gyri and posterior parietal cortex), which previous studies have linked to spatial and temporal monitoring. Our findings extend this research by supporting the domain-general nature of monitoring in the spatial and verbal domains

    Why Youth (heart) Social Network Sites: The Role of Networked Publics in Teenage Social Life

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    Part of the Volume on Youth, Identity, and Digital Media Social network sites like MySpace and Facebook serve as "networked publics." As with unmediated publics like parks and malls, youth use networked publics to gather, socialize with their peers, and make sense of and help build the culture around them. This article examines American youth engagement in networked publics and considers how properties unique to such mediated environments (e.g., persistence, searchability, replicability, and invisible audiences) affect the ways in which youth interact with one another. Ethnographic data is used to analyze how youth recognize these structural properties and find innovative ways of making these systems serve their purposes. Issues like privacy and impression management are explored through the practices of teens and youth participation in social network sites is situated in a historical discussion of youth's freedom and mobility in the United States

    Gaze and body orientation as an apparatus for patient inclusion into/exclusion from a patient-centred framework of communication

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    Dialogue interpreter training has traditionally focused on the way in which the interpreter manages, and maintains, verbal interaction between the primary participants while it seems to overlook the importance of specific non-verbal aspects that are inherent in mediated interaction. This article presents an alternative method for the training of medical interpreters by drawing on research on non-verbal communication in interpreter-mediated consultations with a view to drawing attention to the interpreter's impact on the patient's inclusion in a patient-centred framework during mediated consultations. More specifically, it provides evidence of non-verbal interaction that might open up new trajectories in the interpreters' training by foregrounding the impact of the interpreter's and others' direction of gaze and body orientation on the accomplishment and maintenance - or lack thereof - of a patient-centred framework of communication. The present article reports on findings that emerged from the analysis of selected excerpts of authentic interpreter-mediated consultations within the framework of a training experiment. Coded instances of interaction are analysed by relying on Goffman's 'ratification process', Goodwin's 'participation and engagement frameworks' and Norris' 'modal density foreground-background continuum'. Hospital ethical approval and participants' written informed consent were obtained prior to the collection of data

    The role of visual and mechanosensory cues in structuring forward flight in Drosophila melanogaster

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    It has long been known that many flying insects use visual cues to orient with respect to the wind and to control their groundspeed in the face of varying wind conditions. Much less explored has been the role of mechanosensory cues in orienting insects relative to the ambient air. Here we show that Drosophila melanogaster, magnetically tethered so as to be able to rotate about their yaw axis, are able to detect and orient into a wind, as would be experienced during forward flight. Further, this behavior is velocity dependent and is likely subserved, at least in part, by the Johnston's organs, chordotonal organs in the antennae also involved in near-field sound detection. These wind-mediated responses may help to explain how flies are able to fly forward despite visual responses that might otherwise inhibit this behavior. Expanding visual stimuli, such as are encountered during forward flight, are the most potent aversive visual cues known for D. melanogaster flying in a tethered paradigm. Accordingly, tethered flies strongly orient towards a focus of contraction, a problematic situation for any animal attempting to fly forward. We show in this study that wind stimuli, transduced via mechanosensory means, can compensate for the aversion to visual expansion and thus may help to explain how these animals are indeed able to maintain forward flight
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