2,435 research outputs found

    Increased mitochondrial and lipid metabolism is a conserved effect of Insulin/PI3K pathway downregulation in adipose tissue

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    The Insulin/IGF-1 signalling (IIS) pathway plays an essential role in the regulation of glucose and lipid homeostasis. At the same time, a reduction in the IIS pathway activity can extend lifespan and healthspan in various model organisms. Amongst a number of body organs that sense and respond to insulin/IGF-1, the adipose tissue has a central role in both the metabolic and lifespan efects of IIS at the organismal level. Genetic inactivation of IIS components specifcally in the adipose tissue has been shown before to improve metabolic profle and extend lifespan in various model organisms. We sought to identify conserved molecular mechanisms that may underlie the benefcial efects of IIS inhibition in the adipose tissue, specifcally at the level of phosphoinositide 3-kinase (PI3K), a key IIS efector molecule. To this end, we inactivated PI3K by genetic means in the fy fat body and by pharmacological inhibition in mammalian adipocytes. Gene expression studies revealed changes to metabolism and upregulation of mitochondrial activity in mouse adipocytes and fy fat bodies with downregulated PI3K, which were confrmed by biochemical assays in mammalian adipocytes. These data suggest that PI3K inactivation has a conserved efect of upregulating mitochondrial metabolism in both fy and mammalian adipose tissue, which likely contributes to the health- and life-span extending efect of IIS pathway downregulation

    Probing Lepton Flavor Violation Signal Induced by R-violating Minimal Supersymmetric Standard Model at a Linear Collider

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    The lepton-flavor violation (LFV) effect at an e+ee^+e^- linear collider (LC), in the frame of R-parity violating minimal supersymmetric standard model is studied. We take the R-parity violating processes e+eeμ±e^+e^-\to e^{\mp}\mu^{\pm} as signal, and define the summation of the two processes as ``experiment'' observable. We find that the cross-section summation can reach O\cal{O}(101)fb(10^1)fb in the parameter space without sneutrino resonance effect(smν~\sqrt{s} \sim m_{\tilde{\nu}}). The summation treatment manifests uniform differential distribution on cosθ\cos\theta, where θ\theta denotes the polar angles of both outgoing e+/ee^+/e^- respectively to incoming electron beam in two signal processes. The uniform feature together with eμe\mu collinearity would help to reduce the SM background dramatically. Consequently we conclude that at a 500GeV500 GeV LC with 480fb1480 fb^{-1} annual luminosity, it's either possible to detect the distinctive R-violating LFV eμe\mu signal, or exclude sneutrino to mν~>1.1TeVm_{\tilde{\nu}}>1.1 TeV at 95% CL in the machine's biennial runtime interval.Comment: 14 pages, 9 figure

    Controlling Style and Semantics in Weakly-Supervised Image Generation

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    We propose a weakly-supervised approach for conditional image generation of complex scenes where a user has fine control over objects appearing in the scene. We exploit sparse semantic maps to control object shapes and classes, as well as textual descriptions or attributes to control both local and global style. In order to condition our model on textual descriptions, we introduce a semantic attention module whose computational cost is independent of the image resolution. To further augment the controllability of the scene, we propose a two-step generation scheme that decomposes background and foreground. The label maps used to train our model are produced by a large-vocabulary object detector, which enables access to unlabeled data and provides structured instance information. In such a setting, we report better FID scores compared to fully-supervised settings where the model is trained on ground-truth semantic maps. We also showcase the ability of our model to manipulate a scene on complex datasets such as COCO and Visual Genome.Comment: European Conference on Computer Vision (ECCV) 2020, Spotlight. Code at https://github.com/dariopavllo/style-semantic

    Spatiotemporal Water Yield Variations and Influencing Factors in the Lhasa River Basin, Tibetan Plateau

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    Understanding the spatiotemporal characteristics of water yield and its influencing factors is important for water resources management. In this study, we used the seasonal water yield model (SWYM) to assess the spatiotemporal water yield changes of the Lhasa River Basin from 1990 to 2015, and analyzed its influencing factors by focusing on precipitation, land cover, and normalized difference vegetation index (NDVI) change. We first examined the model through Morris screening sensitivity analysis and validated it with the observed flow data. Spatiotemporal variation of three indices of water yield, baseflow, quick flow, and local recharge were then assessed. Results showed that from 1990 to 2015, the baseflow, local recharge, and quick flow decreased by 67.03%, 80.21%, and 37.03%, respectively. The spatial pattern of water yield remained mostly unchanged. According to the contribution analysis, precipitation and NDVI change were the main factors affecting water yield in the Lhasa River Basin, while land cover change began to exert greater influence after 2010. A combination of climate change and human activities therefore drive water yield change, especially through vegetation change. Water resources management strategies should thus take into account the combination of rapidly changing climate and human activities

    Inner Space Preserving Generative Pose Machine

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    Image-based generative methods, such as generative adversarial networks (GANs) have already been able to generate realistic images with much context control, specially when they are conditioned. However, most successful frameworks share a common procedure which performs an image-to-image translation with pose of figures in the image untouched. When the objective is reposing a figure in an image while preserving the rest of the image, the state-of-the-art mainly assumes a single rigid body with simple background and limited pose shift, which can hardly be extended to the images under normal settings. In this paper, we introduce an image "inner space" preserving model that assigns an interpretable low-dimensional pose descriptor (LDPD) to an articulated figure in the image. Figure reposing is then generated by passing the LDPD and the original image through multi-stage augmented hourglass networks in a conditional GAN structure, called inner space preserving generative pose machine (ISP-GPM). We evaluated ISP-GPM on reposing human figures, which are highly articulated with versatile variations. Test of a state-of-the-art pose estimator on our reposed dataset gave an accuracy over 80% on PCK0.5 metric. The results also elucidated that our ISP-GPM is able to preserve the background with high accuracy while reasonably recovering the area blocked by the figure to be reposed.Comment: http://www.northeastern.edu/ostadabbas/2018/07/23/inner-space-preserving-generative-pose-machine

    Shear-strain-mediated magnetoelectric effects revealed by imaging.

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    Large changes in the magnetization of ferromagnetic films can be electrically driven by non-180° ferroelectric domain switching in underlying substrates, but the shear components of the strains that mediate these magnetoelectric effects have not been considered so far. Here we reveal the presence of these shear strains in a polycrystalline film of Ni on a 0.68Pb(Mg1/3Nb2/3)O3-0.32PbTiO3 substrate in the pseudo-cubic (011)pc orientation. Although vibrating sample magnetometry records giant magnetoelectric effects that are consistent with the hitherto expected 90° rotations of a global magnetic easy axis, high-resolution vector maps of magnetization (constructed from photoemission electron microscopy data, with contrast from X-ray magnetic circular dichroism) reveal that the local magnetization typically rotates through smaller angles of 62-84°. This shortfall with respect to 90° is a consequence of the shear strain associated with ferroelectric domain switching. The non-orthogonality represents both a challenge and an opportunity for the development and miniaturization of magnetoelectric devices.Isaac Newton Trust, the Royal Society, University of Wisconsin Madison, Agència de Gestió d'Ajuts Universitaris i de Recercaa - Generalitat de Cataluny

    Behavioural determinants of gene flow in malaria vector populations: Anopheles gambiae males select large females as mates

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    BACKGROUND: Plasmodium-refractory mosquitoes are being rapidly developed for malaria control but will only succeed if they can successfully compete for mates when released into the wild. Pre-copulatory behavioural traits maintain genetic population structure in wild mosquito populations and mating barriers have foiled previous attempts to control malaria vectors through sterile male release. METHODS: Varying numbers of virgin male and female Anopheles gambiae Giles, from two strains of different innate sizes, were allowed to mate under standardized conditions in laboratory cages, following which, the insemination status, oviposition success and egg batch size of each female was assessed. The influence of male and female numbers, strain combination and female size were determined using logistic regression, correlation analysis and a simple mechanistic model of male competition for females. RESULTS: Male An. gambiae select females on the basis of size because of much greater fecundity among large females. Even under conditions where large numbers of males must compete for a smaller number of females, the largest females are more likely to become inseminated, to successfully oviposit and to produce large egg batches. CONCLUSIONS: Sexual selection, on the basis of size, could either promote or limit the spread of malaria-refractory genes into wild populations and needs to be considered in the continued development and eventual release of transgenic vectors. Fundamental studies of behavioural ecology in malaria vectors such as An. gambiae can have important implications for malaria control and should be prioritised for more extensive investigation in the future

    Unparticle Physics in Single Top Signals

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    We study the single production of top quarks in e+e,epe^+e^-, ep and pppp collisions in the context of unparticle physics through the Flavor Violating (FV) unparticle vertices and compute the total cross sections for single top production as functions of scale dimension d_{\U}. We find that among all, LHC is the most promising facility to probe the unparticle physics via single top quark production processes.Comment: 14 pages, 10 figure

    Unparticle Searches Through Compton Scattering

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    We investigate the effects of unparticles on Compton scattering, e gamma -> e gamma based on a future e^+e^- linear collider such as the CLIC. For different polarization configurations, we calculate the lower limits of the unparticle energy scale Lambda_U for a discovery reach at the center of mass energies sqrt(s)=0.5 TeV- 3 TeV. It is shown that, especially, for smaller values of the mass dimension d, (1 <d <1.3), and for high energies and luminosities of the collider these bounds are very significant. As a stringent limit, we find Lambda_U>80 TeV for d<1.3 at sqrt(s)=3 TeV, and 1 ab^(-1) integrated luminosity per year, which is comparable with the limits calculated from other low and high energy physics implications.Comment: Table 1 and 2 have been combined as Table 1, references updated, minor typos have been correcte
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