454 research outputs found

    Mixing-Demixing transition in 1D boson-fermion mixture at low fermion densities

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    We numerically investigated the mixing-demixing transition of the boson-fermion mixture on a 1D lattice at an incommensurate filling with the fermion density being kept below the boson density. The phase diagram we obtained suggested that the decrease of the number of the fermions drove the system into the demixing phase

    Optimization of 3D Cooling Channels in Injection Molding using DRBEM and Model Reduction

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    Issu de : ESAFORM 2009 - 12th ESAFORM Conference on material forming, Enschede, THE NETHERLANDS, 27-29 April 2009International audienceToday, around 30% of manufactured plastic goods rely on injection moulding. The cooling time can represent more than 70% of the injection cycle. In this process, heat transfer during the cooling step has a great influence both on the quality of the final parts that are produced, and on the moulding cycle time. In the numerical solution of three-dimensional boundary value problems, the matrix size can be so large that it is beyond a computer capacity to solve it. To overcome this difficulty, we develop an iterative dual reciprocity boundary element method (DRBEM) to solve Poisson’s equation without the need of assembling a matrix. This yields a reduction of the computational space dimension from 3D to 2D, avoiding full 3D remeshing. Only the surface of the cooling channels needs to be remeshed at each evaluation required by the optimisation algorithm. For more efficiency, DRBEM computing results are extracted stored and exploited in order to construct a model with very few degrees of freedom. This approach is based on a model reduction technique known as proper orthogonal (POD) or Karhunen-Loùve decompositions. We introduce in this paper a practical methodology to optimise both the position and the shape of the cooling channels in 3D injection moulding processes. First, we propose an implementation of the model reduction in the 3D transient BEM solver. This reduction permits to reduce considerably the computing time required by each direct computation. Secondly, we present an optimisation methodology applied to different injection cooling problems. For example, we can minimize the maximal temperature on the cavity surface subject to a temperature uniformityconstraint. Thirdly, we compare our results obtained by our approach with experimental results to show that our optimisation methodology is viable

    Bose-Fermi mixtures in 1D optical superlattices

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    The zero temperature phase diagram of binary boson-fermion mixtures in two-colour superlattices is investigated. The eigenvalue problem associated with the Bose-Fermi-Hubbard Hamiltonian is solved using an exact numerical diagonalization technique, supplemented by an adaptive basis truncation scheme. The physically motivated basis truncation allows to access larger systems in a fully controlled and very flexible framework. Several experimentally relevant observables, such as the matter-wave interference pattern and the condensatefraction, are investigated in order to explore the rich phase diagram. At symmetric half filling a phase similar to the Mott-insulating phase in a commensurate purely bosonic system is identified and an analogy to recent experiments is pointed out. Furthermore a phase of complete localization of the bosonic species generated by the repulsive boson-fermion interaction is identified. These localized condensates are of a different nature than the genuine Bose-Einstein condensates in optical lattices.Comment: 18 pages, 9 figure

    Maternal neurofascin-specific autoantibodies bind to structures of the fetal nervous system during pregnancy, but have no long term effect on development in the rat

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    Neurofascin was recently reported as a target for axopathic autoantibodies in patients with multiple sclerosis (MS), a response that will exacerbate axonal pathology and disease severity in an animal model of multiple sclerosis. As transplacental transfer of maternal autoantibodies can permanently damage the developing nervous system we investigated whether intrauterine exposure to this neurofascin-specific response had any detrimental effect on white matter tract development. To address this question we intravenously injected pregnant rats with either a pathogenic anti-neurofascin monoclonal antibody or an appropriate isotype control on days 15 and 18 of pregnancy, respectively, to mimic the physiological concentration of maternal antibodies in the circulation of the fetus towards the end of pregnancy. Pups were monitored daily with respect to litter size, birth weight, growth and motor development. Histological studies were performed on E20 embryos and pups sacrificed on days 2, 10, 21, 32 and 45 days post partum. Results: Immunohistochemistry for light and confocal microscopy confirmed passively transferred anti-neurofascin antibody had crossed the placenta to bind to distinct structures in the developing cortex and cerebellum. However, this did not result in any significant differences in litter size, birth weight, or general physical development between litters from control mothers or those treated with the neurofascin-specific antibody. Histological analysis also failed to identify any neuronal or white matter tract abnormalities induced by the neurofascin-specific antibody. Conclusions: We show that transplacental transfer of circulating anti-neurofascin antibodies can occur and targets specific structures in the CNS of the developing fetus. However, this did not result in any pre- or post-natal abnormalities in the offspring of the treated mothers. These results assure that even if anti-neurofascin responses are detected in pregnant women with multiple sclerosis these are unlikely to have a negative effect on their children

    Review: ‘Gimme five’: future challenges in multiple sclerosis. ECTRIMS Lecture 2009

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    This article is based on the ECTRIMS lecture given at the 25th ECTRIMS meeting which was held in DĂŒsseldorf, Germany, from 9 to 12 September 2009. Five challenges have been identified: (1) safeguarding the principles of medical ethics; (2) optimizing the risk/benefit ratio; (3) bridging the gap between multiple sclerosis and experimental autoimmune encephalitis; (4) promoting neuroprotection and repair; and (5) tailoring multiple sclerosis therapy to the individual patient. Each of these challenges will be discussed and placed in the context of current research into the pathogenesis and treatment of multiple sclerosis

    Endometriotic Mass After Hysterectomy in a 61 Year Old Post-menopausal Woman: A Case Report and Update.

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    Endometriosis is a common, hormone-dependent gynecologic disease. Undiagnosed in large proportion of women, managing therapies depend on the impact of quality of life and includes hormonal treatment and pelvic surgery. Less likely endometriosis can occur in post-menopausal women. Malignant transformation of endometriosis is a rare but well-described process, most of time occurring in the ovary, and justifies the practitioner not to underestimate this pathology. We present a case of a 61 year old woman with a symptomatic endometriotic pelvic mass, status post hysterectomy, with no history of endometriosis diagnosed beforehand

    InfoSyll: A Syllabary Providing Statistical Information on Phonological and Orthographic Syllables

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    here is now a growing body of evidence in various languages supporting the claim that syllables are functional units of visual word processing. In the perspective of modeling the processing of polysyllabic words and the activation of syllables, current studies investigate syllabic effects with subtle manipulations. We present here a syllabary of the French language aiming at answering new constraints when designing experiments on the syllable issue. The InfoSyll syllabary provides exhaustive characteristics and statistical information for each phonological syllable (e.g. /fi/) and for its corresponding orthographic syllables (e.g. fi, phi, phy, fee, fix, fis). Variables such as the type and token positional frequencies, the number and frequencies of the correspondences between orthographic and phonological syllables are provided. As discussed, such computations should allow precise controls, manipulations and quantitative descriptions of syllabic variables in the field of psycholinguistic research.SCOPUS: ar.jinfo:eu-repo/semantics/publishe
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