398,915 research outputs found

    Social interaction as a heuristic for combinatorial optimization problems

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    We investigate the performance of a variant of Axelrod's model for dissemination of culture - the Adaptive Culture Heuristic (ACH) - on solving an NP-Complete optimization problem, namely, the classification of binary input patterns of size FF by a Boolean Binary Perceptron. In this heuristic, NN agents, characterized by binary strings of length FF which represent possible solutions to the optimization problem, are fixed at the sites of a square lattice and interact with their nearest neighbors only. The interactions are such that the agents' strings (or cultures) become more similar to the low-cost strings of their neighbors resulting in the dissemination of these strings across the lattice. Eventually the dynamics freezes into a homogeneous absorbing configuration in which all agents exhibit identical solutions to the optimization problem. We find through extensive simulations that the probability of finding the optimal solution is a function of the reduced variable F/N1/4F/N^{1/4} so that the number of agents must increase with the fourth power of the problem size, N∝F4N \propto F^ 4, to guarantee a fixed probability of success. In this case, we find that the relaxation time to reach an absorbing configuration scales with F6F^ 6 which can be interpreted as the overall computational cost of the ACH to find an optimal set of weights for a Boolean Binary Perceptron, given a fixed probability of success

    Objective Styles in Northern Field Science

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    Social studies of science have often treated natural field sites as extensions of the laboratory. But this overlooks the unique specificities of field sites. While lab sites are usually private spaces with carefully controlled borders, field sites are more typically public spaces with fluid boundaries and diverse inhabitants. Field scientists must therefore often adapt their work to the demands and interests of local agents. I propose to address the difference between lab and field in sociological terms, as a difference in style. A field style treats epistemic alterity as a resource rather than an obstacle for objective knowledge production. A sociological stylistics of the field should thus explain how objective science can co-exist with radical conceptual difference. I discuss examples from the Canadian North, focussing on collaborations between state wildlife biologists and managers, on the one hand, and local Aboriginal Elders and hunters, on the other. I argue that a sociological stylistics of the field can help us to better understand how radically diverse agents may collaborate across cultures in the successful production of reliable natural knowledge

    Exploring cultural factors in human-robot interaction: A matter of personality?

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    This paper proposes an experimental study to investigate task-dependence and cultural-background dependence of the personality trait attribution on humanoid robots. In Human-Robot Interaction, as well as in Human-Agent Interaction research, the attribution of personality traits towards intelligent agents has already been researched intensively in terms of the social similarity or complementary rule. These two rules imply that humans either tend to like others with similar personality traits or complementary personality traits more. Even though state of the art literature suggests that similarity attraction happens for virtual agents, and complementary attraction for robots, there are many contradictions in the findings. We assume that searching the explanation for personality trait attribution in the similarity and complementary rule does not take into account important contextual factors. Just like people equate certain personality types to certain professions, we expect that people may have certain personality expectations depending on the context of the task the robot carries out. Because professions have different social meaning in different national culture, we also expect that these task-dependent personality preferences differ across cultures. Therefore suggest an experiment that considers the task-context and the cultural background of users

    The Evolution of Religion: How Cognitive By-Products, Adaptive Learning Heuristics, Ritual Displays, and Group Competition Generate Deep Commitments to Prosocial Religio

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    Understanding religion requires explaining why supernatural beliefs, devotions, and rituals are both universal and variable across cultures, and why religion is so often associated with both large-scale cooperation and enduring group conflict. Emerging lines of research suggest that these oppositions result from the convergence of three processes. First, the interaction of certain reliably developing cognitive processes, such as our ability to infer the presence of intentional agents, favors—as an evolutionary by-product—the spread of certain kinds of counterintuitive concepts. Second, participation in rituals and devotions involving costly displays exploits various aspects of our evolved psychology to deepen people's commitment to both supernatural agents and religious communities. Third, competition among societies and organizations with different faith-based beliefs and practices has increasingly connected religion with both within-group prosociality and between-group enmity. This connection has strengthened dramatically in recent millennia, as part of the evolution of complex societies, and is important to understanding cooperation and conflict in today's world.by-product hypothesis, credibility enhancing displays, cultural 40 transmission, cooperation, group competition, high gods,min

    Toxic Tau Oligomers Modulated by Novel Curcumin Derivatives

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    The pathological aggregation and accumulation of tau, a microtubule-associated protein, is a common feature amongst more than 18 different neurodegenerative diseases that are collectively known as tauopathies. Recently, it has been demonstrated that the soluble and hydrophobic tau oligomers are highly toxic in vitro due to their capacity towards seeding tau misfolding, thereby propagating the tau pathology seen across different neurodegenerative diseases. Modulating the aggregation state of tau oligomers through the use of small molecules could be a useful therapeutic strategy to target their toxicity, regardless of other factors involved in their formation. In this study, we screened and tested a small library of newly synthesized curcumin derivatives against preformed recombinant tau oligomers. Our results show that the curcumin derivatives affect and modulate the tau oligomer aggregation pathways, converting to a more aggregated non-toxic state as assessed in the human neuroblastoma SH-SY5Y cell line and primary cortical neuron cultures. These results provide insight into tau aggregation and may become a basis for the discovery of new therapeutic agents, as well as advance the diagnostic field for the detection of toxic tau oligomers

    Co-culture of Yeast Antagonists of Fusarium Head Blight and their Effect on Disease Development in Wheat

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    Multistrain mixtures of biocontrol agents which can reduce plant disease to a greater extent than the individual strains of the mixture, commonly, are prepared by blending separately produced fermentation products. Co-cultivation of strains to equivalent biomass yields would provide mixture advantages without incurring the cost disadvantages of multiple fermentation and processing protocols. Fusariwn Head Blight (FHB) antagonists Cryptococcus flavescens OR 182.9 (NRRL Y-302l6), C. aureus OH 181.1 (NRRL Y-302l5) and C. aureus OR 181.1 (NRRL Y -30215), were grown in two- and three-strain co-cultures to assess the quality and efficacy of the fermentation end products produced. Final cell counts of component strains of all co-cultures produced were equivalent when plated on a medilllll that contained the trisaccharide melezitose as a sole carbon source and produced colonies of strain-distinguishable sizes. Co-cultures of C. flavescens OH 182.9 and C. aureus OH 71.4 significantly reduced FHB disease severity (32%, p = 0.05, Dunnett\u27s t-test) when averaged across four greenhouse studies. In wheat field trials, biomass from co-cultures of these two strains reduced FHB incidence in some cases but rarely other FHB disease parameters (p = 0.05, Bonferoni mean separation). Relative Performance Index (RPI) analysis of the overall effect of treatments at both field sites revealed that treatment with the OH 71.4 and OH 182.9 co-culture significantly reduced FHB, as evidence by a higher RPI value than for the control, while the individual strains did not. The potential for obtaining superior efficacy and cost benefits with multi-strain cultures of biocontrol agents justifies additional research effort

    Re-introducing Structure: An Historical Analysis and Structural Account of Political Cultures in the Prairie Provinces

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    In this paper, I conduct an historical structural analysis to explain the preservation of political cultures across the Canadian Prairie Provinces. Taking into account Alberta’s historically conservative climate and bootstrap individualism, Saskatchewan’s historically left-leaning policy environment, and Manitoba’s moderate culture between its two prairie compatriots, I explain how these different cultures have persisted using a “polity-centred” approach. Perhaps the most popular explanation for such a “prairie paradox” is “fragment theory”, or looking at different “waves” of settlers including Loyalists, Americans, and early Ontarians, across the prairies. Scholars like Alan Cairns and Jared Wesley have critiqued this approach, arguing that it is the structure of federalism itself that preserves these cultures over time, or that it is the agency of political parties and their campaign literature that reflects political culture back at their populations. A “polity-centred” approach, as I present it here, synthesizes these two critiques of fragment theory to look at how structures both affect political agents and provide tools to affect political culture in their provinces. This is done through, first, a more general examination of how the Canadian federal structure influences political parties, and second, how political parties use structure to affect discourse in a province and preserve or change the political culture. I conclude that polity-centred approaches should be taken more seriously by sociologists and political scientists when looking at political cultures, and that this approach is useful for examining the cultures of other states and substates

    Translating English non-human subjects in agentive contexts : a closer look at Dutch

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    While subjects of transitive action verbs in English and Dutch are typically realized as human agents (see Comrie 1989), both languages also feature instances of nonhuman agents in subject position. However, Vandepitte and Hartsuiker (2011) have shown that there are fewer options in Dutch and that translation issues present themselves in cases where both languages do not overlap. This paper wants to document overlap and differences in terms of non-prototypical subject realization by focussing on the strategies that are used in Dutch translations of six actions verbs (give, demonstrate, show, suggest, offer and tell) in combination with non-human subjects. Results reveal that a fair share of non-human subjects are also translated as such in the target language. Other strategies include occasional humanization of the non-human source text subjects, reduction of valency patterns with reduced agentivity vis-a-vis the English source-text sentences and shifts in the mapping of semantic roles onto syntactic functions

    Effects of trust and public participation on acceptability of renewable energy projects in the Netherlands and China

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    In order to mitigate climate change and its impacts, it is crucial to replace fossil fuels with renewable energy sources. The extent to which renewable energy projects can be implemented largely depends on public acceptability. We studied how public acceptability is influenced by people's trust in agents responsible for renewable energy projects and the influence that people have over decisions regarding these projects. As expected, higher trust and having influence over major decisions regarding the project led to higher project acceptability. Public acceptability was lowest when people had low trust in responsible agents and when people could only influence minor decisions regarding the project. We found a similar pattern of results in our samples in the Netherlands and China, providing initial evidence that trust in responsible agents and public influence over decisions may have similar effects on public acceptability of renewable energy projects across different countries and cultures
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