2,201 research outputs found

    Alaska Natives and American Laws

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    In this thesis we focus on the issue of crowdfunding and especially how a project relates to and embraces its community. While a lot of related research focus on what makes people give, our research instead delve into whether a creator looks upon the sponsors as something more than just a financial resource. To manage this task we used a triangular perspective consisting of a case study, a questionnaire and a netnographic study. The goal was to gain the perspectives of creators, crowdfunding platforms and sponsors on how the communication between the community and the project works and can be improved.        The three crowdfunding platforms we reviewed (Kickstarter, IndieGoGo, Rockethub) all had fairly similar models on how to attract sponsors and make them involved in the project, while the questionnaire and netnographic study demonstrated how a community could contribute in different ways. Based on our results we draw the conclusion that a project can be successful without embracing the creative qualities of its sponsors but doing so also is a waste of a great asset to both current and future projects.

    Stochastic Representations of Ion Channel Kinetics and Exact Stochastic Simulation of Neuronal Dynamics

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    In this paper we provide two representations for stochastic ion channel kinetics, and compare the performance of exact simulation with a commonly used numerical approximation strategy. The first representation we present is a random time change representation, popularized by Thomas Kurtz, with the second being analogous to a "Gillespie" representation. Exact stochastic algorithms are provided for the different representations, which are preferable to either (a) fixed time step or (b) piecewise constant propensity algorithms, which still appear in the literature. As examples, we provide versions of the exact algorithms for the Morris-Lecar conductance based model, and detail the error induced, both in a weak and a strong sense, by the use of approximate algorithms on this model. We include ready-to-use implementations of the random time change algorithm in both XPP and Matlab. Finally, through the consideration of parametric sensitivity analysis, we show how the representations presented here are useful in the development of further computational methods. The general representations and simulation strategies provided here are known in other parts of the sciences, but less so in the present setting.Comment: 39 pages, 6 figures, appendix with XPP and Matlab cod

    Apes communicate about absent and displaced objects: methodology matters

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    Displaced reference is the ability to refer to an item that has been moved (displaced) in space and/or time, and has been called one of the true hallmarks of referential communication. Several studies suggest that nonhuman primates have this capability, but a recent experiment concluded that in a specific situation (absent entities) human infants display displaced reference but chimpanzees do not. Here we show that chimpanzees and bonobos of diverse rearing histories are capable of displaced reference to absent and displaced objects. It is likely that some of the conflicting findings from animal cognition studies are due to relatively minor methodological differences, but are compounded by interpretation errors. Comparative studies are of great importance in elucidating the evolution of human cognition, however, greater care must be taken with methodology and interpretation for these studies to accurately reflect species differences

    Gambling on the circumplex of affect: An empirical investigation of incidental and anticipated emotional influences on risky choice.

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    Affective decision-making has begun to change the face of the traditional decision science paradigm (Loewenstein, Weber, Hsee, & Welch, 2001), forcing researchers to consider direct influences of affect on both cognition and behavior, and no longer viewing affect as simple byproduct of each. In what follows, this more modern view of decision-making has been chronicled and summarized, focusing the reader on two broad types of affective influences: those attributable to incidental and expected (or anticipatory) affect. An attempt is made to combine these two types of affective influences into a more general theory of affective decision-making, one that incorporates aspects of the Pleasure-Arousal Hypothesis (Russell & Mehrabian, 1978) and the Circumplex of Affect (Russell & Barrett, 1999). An empirical investigation of this theory was tested using self-report measures of both incidental and expected affect and a certainty equivalency gambling task. Results suggested small direct influences of incidental and expected arousal and valence on gambling choices; yet, little support existed for an indirect effect of incidental affect on the gambling decision through mediating expected affect. Conclusions highlight the promise of a general affective decision-making theory that might explain current paradoxes in risk seeking behaviors, particularly those that occur during adolescence. Appeals were also made, however, for better measurement and methodology within this area of research so that empirically validated propositions can be generalized beyond the pen and well-controlled laboratories

    Kinetic parameter estimation from TGA: Optimal design of TGA experiments

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    This work presents a general methodology to determine kinetic models of solid thermal decomposition with thermogravimetric analysis (TGA) instruments. The goal is to determine a simple and robust kinetic model for a given solid with the minimum of TGA experiments. From this last point of view, this work can be seen as an attempt to find the optimal design of TGA experiments for kinetic modelling. Two computation tools were developed. The first is a nonlinear parameter estimation procedure for identifying parameters in nonlinear dynamical models. The second tool computes the thermogravimetric experiment (here, the programmed temperature profile applied to the thermobalance) required in order to identify the best kinetic parameters, i.e. parameters with a higher statistical reliability. The combination of the two tools can be integrated in an iterative approach generally called sequential strategy. The application concerns the thermal degradation of cardboard in a Setaram TGA instrument and the results that are presented demonstrate the improvements in the kinetic parameter estimation process

    Sex-Specific Linkages Between Taxonomic and Functional Profiles of Tick Gut Microbiomes

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    Ticks transmit the most diverse array of disease agents and harbor one of the most diverse microbial communities. Major progress has been made in the characterization of the taxonomic profiles of tick microbiota. However, the functional profiles of tick microbiome have been comparatively less studied. In this proof of concept we used state-of-the-art functional metagenomics analytical tools to explore previously reported datasets of bacteria found in male and female Ixodes ovatus, Ixodes persulcatus, and Amblyomma variegatum. Results showed that both taxonomic and functional profiles have differences between sexes of the same species. KEGG pathway analysis revealed that male and female of the same species had major differences in the abundance of genes involved in different metabolic pathways including vitamin B, amino acids, carbohydrates, nucleotides, and antibiotics among others. Partial reconstruction of metabolic pathways using KEGG enzymes suggests that tick microbiome form a complex metabolic network that may increase microbial community resilience and adaptability. Linkage analysis between taxonomic and functional profiles showed that among the KEGG enzymes with differential abundance in male and female ticks only 12% were present in single bacterial genera. The rest of these enzymes were found in more than two bacterial genera, and 27% of them were found in five up to ten bacterial genera. Comparison of bacterial genera contributing to the differences in the taxonomic and functional profiles of males and females revealed that while a small group of bacteria has a dual-role, most of the bacteria contribute only to functional or taxonomic differentiation between sexes. Results suggest that the different life styles of male and female ticks exert sex-specific evolutionary pressures that act independently on the phenomes (set of phenotypes) and genomes of bacteria in tick gut microbiota. We conclude that functional redundancy is a fundamental property of male and female tick microbiota and propose that functional metagenomics should be combined with taxonomic profiling of microbiota because both analyses are complementary
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