1,540 research outputs found

    Manin's and Peyre's conjectures on rational points and adelic mixing

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    Let X be the wonderful compactification of a connected adjoint semisimple group G defined over a number field K. We prove Manin's conjecture on the asymptotic (as T\to \infty) of the number of K-rational points of X of height less than T, and give an explicit construction of a measure on X(A), generalizing Peyre's measure, which describes the asymptotic distribution of the rational points G(K) on X(A). Our approach is based on the mixing property of L^2(G(K)\G(A)) which we obtain with a rate of convergence.Comment: to appear in Ann. Sci. Ecole Norm. Su

    Quantifying sudden changes in dynamical systems using symbolic networks

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    We characterise the evolution of a dynamical system by combining two well-known complex systems' tools, namely, symbolic ordinal analysis and networks. From the ordinal representation of a time-series we construct a network in which every node weights represents the probability of an ordinal patterns (OPs) to appear in the symbolic sequence and each edges weight represents the probability of transitions between two consecutive OPs. Several network-based diagnostics are then proposed to characterize the dynamics of different systems: logistic, tent and circle maps. We show that these diagnostics are able to capture changes produced in the dynamics as a control parameter is varied. We also apply our new measures to empirical data from semiconductor lasers and show that they are able to anticipate the polarization switchings, thus providing early warning signals of abrupt transitions.Comment: 18 pages, 9 figures, to appear in New Journal of Physic

    From non-Markovian dissipation to spatiotemporal control of quantum nanodevices

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    Funding: TL, AWC and BWL thank the Defence Science and Technology Laboratory (Dstl) and Direction Générale de l’Armement (DGA) for support through the Anglo-French PhD scheme. BWL acknowledges support from EPSRC grant EP/T014032/1.Nanodevices exploiting quantum effects are critically important elements of future quantum technologies (QT), but their real-world performance is strongly limited by decoherence arising from local `environmental' interactions. Compounding this, as devices become more complex, i.e. contain multiple functional units, the `local' environments begin to overlap, creating the possibility of environmentally mediated decoherence phenomena on new time-and-length scales. Such complex and inherently non-Markovian dynamics could present a challenge for scaling up QT, but – on the other hand – the ability of environments to transfer `signals' and energy might also enable sophisticated spatiotemporal coordination of inter-component processes, as is suggested to happen in biological nanomachines, like enzymes and photosynthetic proteins. Exploiting numerically exact many body methods (tensor networks) we study a fully quantum model that allows us to explore how propagating environmental dynamics can instigate and direct the evolution of spatially remote, non-interacting quantum systems. We demonstrate how energy dissipated into the environment can be remotely harvested to create transient excited/reactive states, and also identify how reorganisation triggered by system excitation can qualitatively and reversibly alter the `downstream' kinetics of a `functional' quantum system. With access to complete system-environment wave functions, we elucidate the microscopic processes underlying these phenomena, providing new insight into how they could be exploited for energy efficient quantum devices.Peer reviewe

    Atlas Linguistique de la Polynesie Francaise - Linguistic Atlas of French Polynesia

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    The idea of producing a 'Linguistic Atlas of French Polynesia' was first conceived at the end of the 1980s, when the University of French Polynesia was founded. A fair part of our efforts were devoted to producing a book fully accessible to the two major scientific languages, French and English. The subjects addressed in this book include the human body, life and health ; society ; traditional techniques and activities, and finally the physical environment (flora and fauna). The work so far accomplished should, we hope, encourage enthusiasts of Polynesian languages and cultures including future generations of researchers to continue along the path.The present publication, including the collection of the data that made it possible, was funded by the Université de la Polynésie français

    Grouping Pig-Specific Responses to Mitogen with Similar Responder Animals may Facilitate the Interpretation of Results Obtained in an Out-Bred Animal Model

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    Copyright: © 2014 J. Alex Pasternak, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.Peer ReviewedPig peripheral blood-derived mononuclear cells (PBMCs) and lamina propria mononuclear cells (LPMCs) stimulated with mitogens ex vivo can show significant animal-to-animal variation lead to difficulty in interpreting responses in an out-bred animal species. Mixed-cell populations were stimulated ex vivo with 2.5 μg/ml Con A or 2.5 ng/ml PMA plus 250 ng/ml ionomycin (PMAi; (LPCMs only)) or media alone for 72 hours. Supernatants were then tested for cytokine production using a Bioplex assay for porcine IFNα, IFNγ, IL-10, and IL-12. Unstimulated PBMCs had significant levels of IL-10 and the median value for this group decreased in the presence of Con A. Con A did, however, induce production of IFNα and IFNγ, but not IL-12 in this cell population. In contrast, unstimulated and Con A-stimulated LPMCs produced negligible IL-10, IFNα, IFNγ, and the majority of animals’ LPMCs showed negligible IL-12 production in response to Con A. In contrast, LPMCs stimulated with PMAi produced IFNγ suggesting cytokine production is mitogen–specific response. When we tracked animal-specific responses, we observed that discrete subsets of animal’s PBMCs responded to Con A with significantly increased or decreased IL-10 production relative to unstimulated cells. Further, in the LPMCs, some cells produced no IL-12 in response to Con A but showed augmented production in response to PMAi, while others showed production of IL-12 in response to Con A but no response to PMAi. Flow cytometric analysis showed that the PBMCs were a mixture of CD3+ T cells>CD21+ B cells>CD172+ myeloid cells whereas the LPMCs consisted of mainly Cytotoxic T cells and Natural Killer cells. The percentage of CD8α+CD4+ antigen-experienced T cells was greater in the LPMCs relative to the PBMCs. As expected in an out-bred species, animal-specific differences in cytokine production in response to stimulants exist and may confound interpretation of results unless tracked individually

    Detection of melanoma from dermoscopic images of naevi acquired under uncontrolled conditions.

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    International audienceBACKGROUND AND OBJECTIVE: Several systems for the diagnosis of melanoma from images of naevi obtained under controlled conditions have demonstrated comparable efficiency with dermatologists. However, their robustness to analyze daily routine images was sometimes questionable. The purpose of this work is to investigate to what extent the automatic melanoma diagnosis may be achieved from the analysis of uncontrolled images of pigmented skin lesions. MATERIALS AND METHODS: Images were acquired during regular practice by two dermatologists using Reflex 24 x 36 cameras combined with Heine Delta 10 dermascopes. The images were then digitalized using a scanner. In addition, five senior dermatologists were asked to give the diagnosis and therapeutic decision (exeresis) for 227 images of naevi, together with an opinion about the existence of malignancy-predictive features. Meanwhile, a learning by sample classifier for the diagnosis of melanoma was constructed, which combines image-processing with machine-learning techniques. After an automatic segmentation, geometric and colorimetric parameters were extracted from images and selected according to their efficiency in predicting malignancy features. A diagnosis was subsequently provided based on selected parameters. An extensive comparison of dermatologists' and computer results was subsequently performed. RESULTS AND CONCLUSION: The KL-PLS-based classifier shows comparable performances with respect to dermatologists (sensitivity: 95% and specificity: 60%). The algorithm provides an original insight into the clinical knowledge of pigmented skin lesions

    SkeleMotion: A New Representation of Skeleton Joint Sequences Based on Motion Information for 3D Action Recognition

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    International audienceDue to the availability of large-scale skeleton datasets, 3D human action recognition has recently called the attention of computer vision community. Many works have fo-cused on encoding skeleton data as skeleton image representations based on spatial structure of the skeleton joints, in which the temporal dynamics of the sequence is encoded as variations in columns and the spatial structure of each frame is represented as rows of a matrix. To further improve such representations, we introduce a novel skeleton image representation to be used as input of Convolutional Neural Networks (CNNs), named SkeleMotion. The proposed approach encodes the temporal dynamics by explicitly computing the magnitude and orientation values of the skeleton joints. Different temporal scales are employed to compute motion values to aggregate more temporal dynamics to the representation making it able to capture long-range joint interactions involved in actions as well as filtering noisy motion values. Experimental results demonstrate the effectiveness of the proposed representation on 3D action recognition outperforming the state-of-the-art on NTU RGB+D 120 dataset
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