1,688 research outputs found

    Overview of Constrained PARAFAC Models

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    In this paper, we present an overview of constrained PARAFAC models where the constraints model linear dependencies among columns of the factor matrices of the tensor decomposition, or alternatively, the pattern of interactions between different modes of the tensor which are captured by the equivalent core tensor. Some tensor prerequisites with a particular emphasis on mode combination using Kronecker products of canonical vectors that makes easier matricization operations, are first introduced. This Kronecker product based approach is also formulated in terms of the index notation, which provides an original and concise formalism for both matricizing tensors and writing tensor models. Then, after a brief reminder of PARAFAC and Tucker models, two families of constrained tensor models, the co-called PARALIND/CONFAC and PARATUCK models, are described in a unified framework, for NthN^{th} order tensors. New tensor models, called nested Tucker models and block PARALIND/CONFAC models, are also introduced. A link between PARATUCK models and constrained PARAFAC models is then established. Finally, new uniqueness properties of PARATUCK models are deduced from sufficient conditions for essential uniqueness of their associated constrained PARAFAC models

    On the effect of rotation on magnetohydrodynamic turbulence at high magnetic Reynolds number

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    This article is focused on the dynamics of a rotating electrically conducting fluid in a turbulent state. As inside the Earth's core or in various industrial processes, a flow is altered by the presence of both background rotation and a large scale magnetic field. In this context, we present a set of 3D direct numerical simulations of incompressible decaying turbulence. We focus on parameters similar to the ones encountered in geophysical and astrophysical flows, so that the Rossby number is small, the interaction parameter is large, but the Elsasser number, defining the ratio between Coriolis and Lorentz forces, is about unity. These simulations allow to quantify the effect of rotation and thus inertial waves on the growth of magnetic fluctuations due to Alfv\'en waves. Rotation prevents the occurrence of equipartition between kinetic and magnetic energies, with a reduction of magnetic energy at decreasing Elsasser number {\Lambda}. It also causes a decrease of energy transfer mediated by cubic correlations. In terms of flow structure, a decrease of {\Lambda} corresponds to an increase in the misalignment of velocity and magnetic field.Comment: 18 pages, 12 figure

    Segregation during directional melting and its implications on seeded crystal growth: A theoretical analysis

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    Directional melting of binary systems, as encountered during seeding in melt growth, is analyzed for concurrent compositional changes at the crystal-melt interface. It is shown that steady state conditions cannot normally be reached during seeding and that the growth interface temperature at the initial stages of seeded growth is a function of backmelt conditions. The theoretical treatment is numerically applied to Hg1-xCdXTe and Ga-doped Ge

    Long-term written language experience affects grammaticality judgments and usage but not priming of spoken sentences

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    ‘Book language’ offers a richer linguistic experience than typical conversational speech in terms of its syntactic properties. Here, we investigated the role of long-term syntactic experience on syntactic knowledge and processing. In a pre-registered study with 161 adult native Dutch speakers with varying levels of literacy, we assessed the contribution of individual differences in written language experience to offline and online syntactic processes. Offline syntactic knowledge was assessed as accuracy in an auditory grammaticality judgment task in which we tested violations of four Dutch grammatical norms. Online syntactic processing was indexed by syntactic priming of the Dutch dative alternation, using a comprehension-to-production priming paradigm with auditory presentation. Controlling for the contribution of non-verbal IQ, verbal working memory, and processing speed, we observed a robust effect of literacy experience on the detection of grammatical norm violations in spoken sentences, suggesting that exposure to the syntactic complexity and diversity of written language has specific benefits for general (modality-independent) syntactic knowledge. We replicated previous results by finding robust comprehension-to-production structural priming, both with and without lexical overlap between prime and target. Although literacy experience affected the usage of syntactic alternates in our large sample, it did not modulate their priming. We conclude that amount of experience with written language increases explicit awareness of grammatical norm violations and changes the usage of (PO vs. DO) dative spoken sentences but has no detectable effect on their implicit syntactic priming in proficient language users. These findings constrain theories about the effect of long-term experience on syntactic processing

    Women's view on sexual intercourse and physical abuse : results from a cross-sectional survey in villages surrounding Bobo-Dioulasso, Burkina Faso

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    Our objective is to understand what do verbal and physical interactions within the couple as declared by women tell us about their related autonomy regarding sexual intercourse with their regular partner. Data were gathered thanks to a baseline KABP survey in 8 villages in Burkina Faso. Overall, 591 women aged 15 to 49 living in a stable union constitute our analysis sample. A low percentage (18.2%) of respondents declares that a woman can refuse to have sex with her partner. However, a large part (77.3%) considers this refusal as an unacceptable reason for wife beating. Multivariate logistic regression shows that the belief in a possibility to refuse sex is higher among women in polygamous union and among those who have their own resources. In contrast, disapproval of wife beating as a reaction to this refusal increases with age. It is also higher among women not denying that their partner has multiple sexual partners. Surprisingly, it is lower among women who have their own economic resources. These findings suggest that programs should work on strong beliefs, which are the result of internalization of gender roles as they may, in patriarchal societies such as Burkina Faso, facilitate acceptance of domestic violence

    Less is more? Package design simplicity and brand perception. An application to champagne labels

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    This article investigates the impact of the package design complexity on brand perception. 3 Champagne labels, representative of 3 graphic design styles observed on the market, were created and then tested among 305 consumers according to a between-subjects experiment. These 3 labels contain the same text but different graphic designs in order to manipulate the level of simplicity/complexity of the package design. The results allow the verification of different proposals from the literature. They demonstrate a significant impact of the package design\u27s level of simplicity on brand perception as well as on consumer\u27s buying choices. Is using ornaments still a crime? Package design complexity and brand perception with application to Champagne labels (PDF Download Available). Available from: https://www.researchgate.net/publication/318012343_Is_using_ornaments_st... [accessed Feb 22 2018]

    Loup et pastoralisme dans les Alpes françaises : état des lieux et perspectives de résolution d'un conflit

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    Le retour du loup en France en 1992, et sa progression le long de l'arc alpin, ne se sont pas faits sans heurts, notamment avec les éleveurs ovins qui ont eu à subir des dommages. Face à la prédation et aux conflits qu'elle engendre, l'Etat, avec le soutien de cofinancements européens, a choisi d'apporter différents éléments de réponses : - par la mise en place dès 1993 d'un système de compensation des dommages ; - en améliorant notre connaissance des loups et de leur répartition sur le territoire français (études de suivi, mise en place du système d'indemnisation des dommages) ; - par la prise en charge des mesures de protection : parcs de contention nocturne, chiens de protection, aide-bergers ; - en permettant aux éleveurs, aux populations locales, aux partenaires et aux différents interlocuteurs de l'Etat de se tenir informés de l'état des connaissances par le biais d'une campagne de communication. Malgré ces dispositions et une amélioration certaine du contexte, le conflit est toujours latent : il faut en analyser les raisons pour en gérer les effets. Dans cette perspective, et dans celle d'une expansion régulière du loup vers de nouveaux territoires, cet article se propose d'apporter, au travers d'une lecture subjective du problème, des éléments de réflexion

    Kinetic study of spiramycin removal from aqueous solution using heterogeneous photocatalysis

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    International audienceSpiramycin macrolide antibiotic (SPM) can be photocatalytically degraded on TiO2 (anatase variety). The experiments are done in a batch reactor and the effect of some key parameters is investigated under low energy of artificial UV light. The reaction rate is affected by varying TiO2 dose, pH and SPM concentration. Under optimized conditions, a photodegradation efficiency of 98% is achieved and the SPM photodegradation follows pseudo-first order kinetics. The Langmuir–Hinshelwood (L–H) model is successfully used to fit the experimental data, indicating the dependence of the reaction rate on the chemical reaction step. The L–H model led to the determination of both reaction kinetic and adsorption/desorption equilibrium constants. In order to give an overall estimate of the by-products, chemical oxygen demand, total organic carbon, and calculated average oxidation state monitor the photodegradation proces
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