234,268 research outputs found

    Fractals in the Nervous System: conceptual Implications for Theoretical Neuroscience

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    This essay is presented with two principal objectives in mind: first, to document the prevalence of fractals at all levels of the nervous system, giving credence to the notion of their functional relevance; and second, to draw attention to the as yet still unresolved issues of the detailed relationships among power law scaling, self-similarity, and self-organized criticality. As regards criticality, I will document that it has become a pivotal reference point in Neurodynamics. Furthermore, I will emphasize the not yet fully appreciated significance of allometric control processes. For dynamic fractals, I will assemble reasons for attributing to them the capacity to adapt task execution to contextual changes across a range of scales. The final Section consists of general reflections on the implications of the reviewed data, and identifies what appear to be issues of fundamental importance for future research in the rapidly evolving topic of this review

    How semiregular are irregular variables?

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    We investigate the question whether there is a real difference in the light change between stars classified as semiregular (SRV) or irregular (Lb) variables by analysing photometric light curves of 12 representatives of each class. Using Fourier analysis we try to find a periodic signal in each light curve and determine the S/N of this signal. For all stars, independent of their variability class we detect a period above the significance threshold. No difference in the measured S/N between the two classes could be found. We propose that the Lb stars can be seen as an extension of the SRVs towards shorter periods and smaller amplitudes. This is in agreement with findings from other quantities which also showed no marked difference between the two classes.Comment: 7 pages, accepted for publication by A

    The influence of television stories on narrative abilities in children

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    This research explores the narrative abilities demonstrated by children aged between 8 and 12 in the production of television stories. The results reveal that not all television stories viewed by children foster the informal education process. One type of story, termed narrativizing, enables children to produce coherent stories which clearly articulate the causal, temporal and motivational relations, as well as the means-end structures, the proximal relations of the intrigue and the distal relations of the plot. Other television stories, denarrativizing stories, tend to induce disarrangements and incoherence at all structural levels of the stories produced by children. This in turn hampers the development of their narrative abilities, which are necessary to the correct development of narrative thought. These results indicate the need to exercise social control over this latter type of fictional television narrative, to which children are exposed throughout their development within the framework of informal education.University of the Basque Country (UPV/EHU), EHU 13/65 Universidad del PaĂ­s Vasco/Euskal Herriko Unibertsitatea (UPV/EHU), GIU 15/14 Universidad del PaĂ­s Vasco/Euskal Herriko Unibertsitatea (UPV/EHU), UFI 11/04 MINECO. Ministerio de EconomĂ­a y Competitividad, BES-2015-071923 Fondo Social Europeo, BES-2015-07192

    Dynamics of agrarian landscapes in Western Thailand : Agro-ecological zonation and agricultural transformations in Kanjanaburi Province: hypotheses for improving farming systems sustainability

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    Ce document traite de la zonation agroécologique à petite échelle, comme outil essentiel dans la recherche orientée sur les systèmes agraires en vue du développement. Ces systèmes sont définis comme modes d'exploitation adaptés à l'environnement (naturel et humain) y compris échanges de produit et patrimoine culturel; l'étude comprend systèmes de production et de culture, et types d'utilisation des sols. Les diverses relations entre éléments sont analysées dans l'espace et le temps de façon à dégager la dynamique des transformations. Le projet a fait intervenir des équipes pluridisciplinaires comprenant agronomes et spécialistes des ressources naturelles en sociologie et télédétection; le tout aux niveaux de la parcelle et de l'exploitation agricole. Le texte, qui comporte un glossaire technique précis, est illustré de six clichés en couleurs (cultures de maïs, cotonnier, manioc, manguiers) et d'une image digitale en couleurs d'une partie de l'ouest de la Thaïlande vue du satellite Landsat-T

    Write Like a Visual Artist: Tracing artists’ work in Canada’s textually mediated art world

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    This study examines the social organisation of Canada’s art world from the standpoint of practising visual artists. Bringing together theories of literacy and institutional ethnography, the article investigates the literacy practices of visual artists, making visible how artists use written texts to participate in public galleries and in the social and institutional relations of the art world. Drawing on extended ethnographic research, including interviews, observational field notes and textual analyses, this study sheds light on the ways visual artists enact particular texts, enact organisational processes, and to enact the social and conceptual worlds they are a part of. Through the lens of visual artists, this study locates two particular texts – the artist statement and the bio statement – in the extended social and institutional relations of the art world.

    The left intraparietal sulcus modulates the selection of low salient stimuli

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    Neuropsychological and functional imaging studies have suggested a general right hemisphere advantage for processing global visual information and a left hemisphere advantage for processing local information. In contrast, a recent transcranial magnetic stimulation study [Mevorach, C., Humphreys, G. W., & Shalev, L. Opposite biases in salience-based selection for the left and right posterior parietal cortex. Nature Neuroscience, 9, 740-742, 2006b] demonstrated that functional lateralization of selection in the parietal cortices on the basis of the relative salience of stimuli might provide an alternative explanation for previous results. In the present study, we applied a whole-brain analysis of the functional magnetic resonance signal when participants responded to either the local or the global levels of hierarchical figures. The task (respond to local or global) was crossed with the saliency of the target level (local salient, global salient) to provide, for the first time, a direct contrast between brain activation related to the stimulus level and that related to relative saliency. We found evidence for lateralization of salience-based selection but not for selection based on the level of processing. Activation along the left intraparietal sulcus (IPS) was found when a low saliency stimulus had to be selected irrespective of its level. A control task showed that this was not simply an effect of task difficulty. The data suggest a specific role for regions along the left IPS in salience-based selection, supporting the argument that previous reports of lateralized responses to local and global stimuli were contaminated by effects of saliency

    National and International Dimensions of the Triple Helix in Japan: University-Industry-Government versus International Co-Authorship Relations

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    International co-authorship relations and university-industry-government ("Triple Helix") relations have hitherto been studied separately. Using Japanese (ISI) publication data for the period 1981-2004, we were able to study both kinds of relations in a single design. In the Japanese file, 1,277,823 articles with at least one Japanese address were attributed to the three sectors, and we know additionally whether these papers were co-authored internationally. Using the mutual information in three and four dimensions, respectively, we show that the Japanese Triple-Helix system has continuously been eroded at the national level. However, since the middle of the 1990s, international co-authorship relations have contributed to a reduction of the uncertainty. In other words, the national publication system of Japan has developed a capacity to retain surplus value generated internationally. In a final section, we compare these results with an analysis based on similar data for Canada. A relative uncoupling of local university-industry relations because of international collaborations is indicated in both national systems

    Video Time: Properties, Encoders and Evaluation

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    Time-aware encoding of frame sequences in a video is a fundamental problem in video understanding. While many attempted to model time in videos, an explicit study on quantifying video time is missing. To fill this lacuna, we aim to evaluate video time explicitly. We describe three properties of video time, namely a) temporal asymmetry, b)temporal continuity and c) temporal causality. Based on each we formulate a task able to quantify the associated property. This allows assessing the effectiveness of modern video encoders, like C3D and LSTM, in their ability to model time. Our analysis provides insights about existing encoders while also leading us to propose a new video time encoder, which is better suited for the video time recognition tasks than C3D and LSTM. We believe the proposed meta-analysis can provide a reasonable baseline to assess video time encoders on equal grounds on a set of temporal-aware tasks.Comment: 14 pages, BMVC 201
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