2,523 research outputs found

    Localization of Multi-Dimensional Wigner Distributions

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    A well known result of P. Flandrin states that a Gaussian uniquely maximizes the integral of the Wigner distribution over every centered disc in the phase plane. While there is no difficulty in generalizing this result to higher-dimensional poly-discs, the generalization to balls is less obvious. In this note we provide such a generalization.Comment: Minor corrections, to appear in the Journal of Mathematical Physic

    A note on the optimality of decomposable entanglement witnesses and completely entangled subspaces

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    Entanglement witnesses (EWs) constitute one of the most important entanglement detectors in quantum systems. Nevertheless, their complete characterization, in particular with respect to the notion of optimality, is still missing, even in the decomposable case. Here we show that for any qubit-qunit decomposable EW (DEW) W the three statements are equivalent: (i) the set of product vectors obeying \bra{e,f}W\ket{e,f}=0 spans the corresponding Hilbert space, (ii) W is optimal, (iii) W=Q^{\Gamma} with Q denoting a positive operator supported on a completely entangled subspace (CES) and \Gamma standing for the partial transposition. While, implications (i)⇒(ii)(i)\Rightarrow(ii) and (ii)⇒(iii)(ii)\Rightarrow(iii) are known, here we prove that (iii) implies (i). This is a consequence of a more general fact saying that product vectors orthogonal to any CES in C^{2}\otimes C^{n} span after partial conjugation the whole space. On the other hand, already in the case of C^{3}\otimes C^{3} Hilbert space, there exist DEWs for which (iii) does not imply (i). Consequently, either (i) does not imply (ii), or (ii) does not imply (iii), and the above transparent characterization obeyed by qubit-qunit DEWs, does not hold in general.Comment: 13 pages, proof of lemma 4 corrected, theorem 3 removed, some parts improve

    The impact of luteal phase support on endometrial estrogen and progesterone receptor expression: a randomized control trial

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    <p>Abstract</p> <p>Background</p> <p>To assess the impact of luteal phase support on the expression of estrogen receptor (ER) alpha and progesterone receptors B (PR-B) on the endometrium of oocyte donors undergoing controlled ovarian hyperstimulation (COH).</p> <p>Methods</p> <p>A prospective, randomized study was conducted in women undergoing controlled ovarian hyperstimulation for oocyte donation. Participants were randomized to receive no luteal support, vaginal progesterone alone, or vaginal progesterone plus orally administered 17 Beta estradiol. Endometrial biopsies were obtained at 4 time points in the luteal phase and evaluated by tissue microarray for expression of ER alpha and PR-B.</p> <p>Results</p> <p>One-hundred and eight endometrial tissue samples were obtained from 12 patients. No differences were found in expression of ER alpha and PR-B among all the specimens with the exception of one sample value.</p> <p>Conclusions</p> <p>The administration of progesterone during the luteal phase of COH for oocyte donor cycles, either with or without estrogen, does not significantly affect the endometrial expression of ER alpha and PR.</p

    Suppressive effect of TNF-α and IL-1 on alveolar fibroblast proliferation in sarcoidosis

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    The nature of soluble factors that regulate fibroblast proliferation have not been finally characterized. Our aim was to study the role of tumour necrosis factor α (TNF-α) and interleukin-1 (IL-1) in the suppressive activity of alveolar macrophages on autologous lung fibroblasts proliferation in sarcoidosis. We found that supernatants recovered from alveolar macrophages suppressed the proliferation of alveolar fibroblast in sarcoidosis by 35.5 ± 1.13% compared to 3 ± 16% in controls (p < 0.001 between the two groups). This suppression correlated with high content of TNF-α and IL-1 in sarcoidosis patients stage II-III (7.7 ± 2.9 ng/ml TNF-α and 157 ± 53 U/ml IL-1 compared to 3.4 ± 2.4 ng/ml TNF-α and 43 U/ml IL-1 in controls; p < 0.01 and p < 0.001, respectively). Both cytokines in sarcoidosis stage I were within the normal ranges. Exogenous TNF-α (1000-0.5 ng/ml) and IL-1 (500-0.24 ng/ml) had an additive suppressive activity on fibroblast proliferation which was partially reversed by indomethacin

    Opportunities for Bandwidth Adaptation in Microsoft Office Documents

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    Microsoft Office, the most popular office productivity suite, produces large documents that can result in long download latencies for platforms with limited bandwidth. To reduce latency and improve the user's experience, these documents need to be adapted for transmission on a limited-bandwidth network. To identify opportunities for adaptation, we characterize documents created by three popular applications from the Microsoft Office suite: Word, PowerPoint, and Excel. Our study encompasses over 12,500 documents retrieved from 935 different Web sites. Our main conclusions are: 1) Microsoft Office documents are large and require adaptation on bandwidth-limited clients; 2) embedded objects and images account for the majority of the data in these documents, with image types being the most popular non-text content, suggesting that adaptation efforts should focus on these elements; 3) compression considerably reduces the size of these documents; and 4) the internal structure of these documents (pages, slides, or sheets) can be used to download elements on demand and reduce user-perceived latency

    Puppeteer: Component-based Adaptation for Mobile Computing

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    Puppeteer is a system for adapting component-based applications in mobile environments. Puppeteer takes advantage of the exported interfaces of these applications and the structured nature of the documents they manipulate to perform adaptation without modifying the applications. The system is structured in a modular fashion, allowing easy addition of new applications and adaptation policies. Our initial prototype focuses on adaptation to limited bandwidth. It runs on Windows NT, and includes support for a variety of adaptation policies for Microsoft PowerPoint and Internet Explorer 5. We demonstrate that Puppeteer can support complex policies without any modification to the application and with little overhead. To the best of our knowledge, previous implementations of adaptations of this nature have relied on modifying the application

    Forms on Vector Bundles Over Hyperbolic Manifolds and the Conformal Anomaly

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    We study gauge theories based on abelian p−p-forms on real compact hyperbolic manifolds. An explicit formula for the conformal anomaly corresponding to skew--symmetric tensor fields is obtained, by using zeta--function regularization and the trace tensor kernel formula. Explicit exact and numerical values of the anomaly for p−p-forms of order up to p=4p=4 in spaces of dimension up to n=10n=10 are then calculated.Comment: 13 pages, 2 table
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