23,037 research outputs found

    Visual Text Correction

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    Videos, images, and sentences are mediums that can express the same semantics. One can imagine a picture by reading a sentence or can describe a scene with some words. However, even small changes in a sentence can cause a significant semantic inconsistency with the corresponding video/image. For example, by changing the verb of a sentence, the meaning may drastically change. There have been many efforts to encode a video/sentence and decode it as a sentence/video. In this research, we study a new scenario in which both the sentence and the video are given, but the sentence is inaccurate. A semantic inconsistency between the sentence and the video or between the words of a sentence can result in an inaccurate description. This paper introduces a new problem, called Visual Text Correction (VTC), i.e., finding and replacing an inaccurate word in the textual description of a video. We propose a deep network that can simultaneously detect an inaccuracy in a sentence, and fix it by replacing the inaccurate word(s). Our method leverages the semantic interdependence of videos and words, as well as the short-term and long-term relations of the words in a sentence. In our formulation, part of a visual feature vector for every single word is dynamically selected through a gating process. Furthermore, to train and evaluate our model, we propose an approach to automatically construct a large dataset for VTC problem. Our experiments and performance analysis demonstrates that the proposed method provides very good results and also highlights the general challenges in solving the VTC problem. To the best of our knowledge, this work is the first of its kind for the Visual Text Correction task

    General Form of the Color Potential Produced by Color Charges of the Quark

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    Constant electric charge ee satisfies the continuity equation μjμ(x)=0\partial_\mu j^{\mu}(x)= 0 where jμ(x)j^\mu(x) is the current density of the electron. However, the Yang-Mills color current density jμa(x)j^{\mu a}(x) of the quark satisfies the equation Dμ[A]jμa(x)=0D_\mu[A] j^{\mu a}(x)= 0 which is not a continuity equation (μjμa(x)0\partial_\mu j^{\mu a}(x)\neq 0) which implies that a color charge qa(t)q^a(t) of the quark is not constant but it is time dependent where a=1,2,...8a=1,2,...8 are color indices. In this paper we derive general form of color potential produced by color charges of the quark. We find that the general form of the color potential produced by the color charges of the quark at rest is given by \Phi^a(x) =A_0^a(t,{\bf x}) =\frac{q^b(t-\frac{r}{c})}{r}\[\frac{{\rm exp}[g\int dr \frac{Q(t-\frac{r}{c})}{r}] -1}{g \int dr \frac{Q(t-\frac{r}{c})}{r}}\]_{ab} where drdr integration is an indefinite integration, ~~ Qab(τ0)=fabdqd(τ0)Q_{ab}(\tau_0)=f^{abd}q^d(\tau_0), ~~r=xX(τ0)r=|{\vec x}-{\vec X}(\tau_0)|, ~~τ0=trc\tau_0=t-\frac{r}{c} is the retarded time, ~~cc is the speed of light, ~~X(τ0){\vec X}(\tau_0) is the position of the quark at the retarded time and the repeated color indices b,db,d(=1,2,...8) are summed. For constant color charge qaq^a we reproduce the Coulomb-like potential Φa(x)=qar\Phi^a(x)=\frac{q^a}{r} which is consistent with the Maxwell theory where constant electric charge ee produces the Coulomb potential Φ(x)=er\Phi(x)=\frac{e}{r}.Comment: Final version, two more sections added, 45 pages latex, accepted for publication in JHE

    Optical fabrication and characterisation of SU-8 disk photonic waveguide heterostructure cavities

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    In order to demonstrate cavity quantum electrodynamics using photonic crystal (PhC) cavities fabricated around self-assembled quantum dots (QDs), reliable spectral and spatial overlap between the cavity mode and the quantum dot is required. We present a method for using photoresist to optically fabricate heterostructure cavities in a PhC waveguide with a combined photolithography and micro-photoluminescence spectroscopy system. The system can identify single QDs with a spatial precision of ±25 nm, and we confirm the creation of high quality factor cavity modes deterministically placed with the same spatial precision. This method offers a promising route towards bright, on-chip single photon sources for quantum information applications

    Transcriptional and functional profilling of human embryonic stem cell-derived cardiomyocytes

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    Human embryonic stemcells (hESCs) can serve as a potentially limitless source of cells that may enable regeneration of diseased tissue and organs. Here we investigate the use of human embryonic stemcell-derived cardiomyocytes (hESC-CMs) in promoting recovery from cardiac ischemia reperfusion injury in a mouse model. Using microarrays, we have described the hESC-CM transcriptome within the spectrum of changes that occur between undifferentiated hESCs and fetal heart cells. The hESC-CMs expressed cardiomyocyte genes at levels similar to those found in 20-week fetal heart cells, making this population a good source of potential replacement cells in vivo. Echocardiographic studies showed significant improvement in heart function by 8 weeks after transplantation. Finally, we demonstrate long-term engraftment of hESC-CMs by using molecular imaging to track cellular localization, survival, and proliferation in vivo. Taken together, global gene expression profiling of hESC differentiation enables a systems-based analysis of the biological processes, networks, and genes that drive hESC fate decisions, and studies such as this will serve as the foundation for future clinical applications of stem cell therapies. © 2008 Cao et al.published_or_final_versio

    Clinical deterioration in community acquired infections associated with lymphocyte upsurge in immunocompetent hosts

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    Clinical deterioration during the course of community-acquired infections can occur as a result of an exaggerated immune response of the host towards the inciting pathogens, leading to immune-mediated tissue damage. Whether a surge in the peripheral lymphocyte count can be used as a surrogate marker indicating the onset of immunopathological tissue damage is not known. In this study, we report the clinical presentations and outcomes of a cohort of immunocompetent patients with non-tuberculous community acquired infections who experienced clinical deterioration during hospital stay (n=85). 12 (14.1%) patients had a surge in lymphocyte count preceding their clinical deteriorations, and their diagnoses included viral pneumonitis (4), viral encephalitis (3), scrub typhus (2), leptospirosis (1), brucellosis (1), and dengue haemorrhagic fever (1). The clinical manifestations during deterioration ranged from interstitial pneumonitis (6), airway obstruction (1), CNS disturbances (4), and systemic capillary leak syndrome (1), all of which were thought to represent immunopathological tissue damages. When compared with patients without lymphocyte surge, these patients were more likely to be infected with fastidious/viral pathogens (0 vs 12; p<0.05), in addition to having lower mean baseline lymphocyte counts (403±181 vs 1143±686 cells/μl; p<0.05). We postulate that the peripheral lymphocyte count may be a useful surrogate marker indicating the presence of immunopathological damage during clinical deterioration in certain infectious diseases. © 2004 Taylor & Francis.postprin

    Stability analysis and quasinormal modes of Reissner Nordstr{\o}m Space-time via Lyapunov exponent

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    We explicitly derive the proper time (τ)(\tau) principal Lyapunov exponent (λp\lambda_{p}) and coordinate time (tt) principal Lyapunov exponent (λc\lambda_{c}) for Reissner Nordstr{\o}m (RN) black hole (BH) . We also compute their ratio. For RN space-time, it is shown that the ratio is λpλc=r0r023Mr0+2Q2\frac{\lambda_{p}}{\lambda_{c}}=\frac{r_{0}}{\sqrt{r_{0}^2-3Mr_{0}+2Q^2}} for time-like circular geodesics and for Schwarzschild BH it is λpλc=r0r03M\frac{\lambda_{p}}{\lambda_{c}}=\frac{\sqrt{r_{0}}}{\sqrt{r_{0}-3M}}. We further show that their ratio λpλc\frac{\lambda_{p}}{\lambda_{c}} may vary from orbit to orbit. For instance, Schwarzschild BH at innermost stable circular orbit(ISCO), the ratio is λpλcrISCO=6M=2\frac{\lambda_{p}}{\lambda_{c}}\mid_{r_{ISCO}=6M}=\sqrt{2} and at marginally bound circular orbit (MBCO) the ratio is calculated to be λpλcrmb=4M=2\frac{\lambda_{p}}{\lambda_{c}}\mid_{r_{mb}=4M}=2. Similarly, for extremal RN BH the ratio at ISCO is λpλcrISCO=4M=223\frac{\lambda_{p}}{\lambda_{c}}\mid_{r_{ISCO}=4M}=\frac{2\sqrt{2}}{\sqrt{3}}. We also further analyse the geodesic stability via this exponent. By evaluating the Lyapunov exponent, it is shown that in the eikonal limit , the real and imaginary parts of the quasi-normal modes of RN BH is given by the frequency and instability time scale of the unstable null circular geodesics.Comment: Accepted in Pramana, 07/09/201

    Sex differences in mathematics and reading achievement are inversely related: within- and across-nation assessment of 10 years of PISA data

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    We analyzed one decade of data collected by the Programme for International Student Assessment (PISA), including the mathematics and reading performance of nearly 1.5 million 15 year olds in 75 countries. Across nations, boys scored higher than girls in mathematics, but lower than girls in reading. The sex difference in reading was three times as large as in mathematics. There was considerable variation in the extent of the sex differences between nations. There are countries without a sex difference in mathematics performance, and in some countries girls scored higher than boys. Boys scored lower in reading in all nations in all four PISA assessments (2000, 2003, 2006, 2009). Contrary to several previous studies, we found no evidence that the sex differences were related to nations’ gender equality indicators. Further, paradoxically, sex differences in mathematics were consistently and strongly inversely correlated with sex differences in reading: Countries with a smaller sex difference in mathematics had a larger sex difference in reading and vice versa. We demonstrate that this was not merely a between-nation, but also a within-nation effect. This effect is related to relative changes in these sex differences across the performance continuum: We did not find a sex difference in mathematics among the lowest performing students, but this is where the sex difference in reading was largest. In contrast, the sex difference in mathematics was largest among the higher performing students, and this is where the sex difference in reading was smallest. The implication is that if policy makers decide that changes in these sex differences are desired, different approaches will be needed to achieve this for reading and mathematics. Interventions that focus on high-achieving girls in mathematics and on low achieving boys in reading are likely to yield the strongest educational benefits

    Non-equilibrium Condensation Process in a Holographic Superconductor

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    We study the non-equilibrium condensation process in a holographic superconductor. When the temperature T is smaller than a critical temperature T_c, there are two black hole solutions, the Reissner-Nordstrom-AdS black hole and a black hole with a scalar hair. In the boundary theory, they can be regarded as the supercooled normal phase and the superconducting phase, respectively. We consider perturbations on supercooled Reissner-Nordstrom-AdS black holes and study their non-linear time evolution to know about physical phenomena associated with rapidly-cooled superconductors. We find that, for T<T_c, the initial perturbations grow exponentially and, eventually, spacetimes approach the hairy black holes. We also clarify how the relaxation process from a far-from-equilibrium state proceeds in the boundary theory by observing the time dependence of the superconducting order parameter. Finally, we study the time evolution of event and apparent horizons and discuss their correspondence with the entropy of the boundary theory. Our result gives a first step toward the holographic understanding of the non-equilibrium process in superconductors.Comment: 20 pages, 7 figure
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