1,111 research outputs found

    511 keV galactic line from first-order phase transitions and primordial black holes

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    Hawking evaporation of primordial black hole (PBH), with mass 3×1017MPBH/M7×10173\times 10^{-17} \lesssim M_{\rm PBH}/M_\odot \lesssim 7\times 10^{-17} and fractional abundance 0.01fPBH0.50.01 \lesssim f_{\rm PBH} \lesssim 0.5, well reproduces 511 keV gamma-ray excess from galaxy center. In this work, we investigated the production mechanism of PBHs base on the first-order phase transition induced by quartic effective thermal potential of a scalar field in dark sector. We found the phase transition with vacuum energy, O(1)B1/4/MeVO(100)\mathcal{O}(1)\lesssim B^{1/4}/{\rm MeV} \lesssim \mathcal{O}(100), produces the desired PBH mass and abundance fraction. Correlated signatures of gravitational wave and extragalactic gamma-ray from phase transition and black hole evaporation, respectively, are within μ\muAres and AMEGO/e-ASTROGAM projected sensitivities

    Civic hacking: a retrospect and an analysis of Collaborative Participation

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    Ministerio de Economía y Competitividad CSO2016-78386-

    Lexical Retrieval Hypothesis in Multimodal Context

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    Multimodal corpora have become an essential language resource for language science and grounded natural language processing (NLP) systems due to the growing need to understand and interpret human communication across various channels. In this paper, we first present our efforts in building the first Multimodal Corpus for Languages in Taiwan (MultiMoco). Based on the corpus, we conduct a case study investigating the Lexical Retrieval Hypothesis (LRH), specifically examining whether the hand gestures co-occurring with speech constants facilitate lexical retrieval or serve other discourse functions. With detailed annotations on eight parliamentary interpellations in Taiwan Mandarin, we explore the co-occurrence between speech constants and non-verbal features (i.e., head movement, face movement, hand gesture, and function of hand gesture). Our findings suggest that while hand gestures do serve as facilitators for lexical retrieval in some cases, they also serve the purpose of information emphasis. This study highlights the potential of the MultiMoco Corpus to provide an important resource for in-depth analysis and further research in multimodal communication studies

    Exploring Affordance and Situated Meaning in Image Captions: A Multimodal Analysis

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    This paper explores the grounding issue regarding multimodal semantic representation from a computational cognitive-linguistic view. We annotate images from the Flickr30k dataset with five perceptual properties: Affordance, Perceptual Salience, Object Number, Gaze Cueing, and Ecological Niche Association (ENA), and examine their association with textual elements in the image captions. Our findings reveal that images with Gibsonian affordance show a higher frequency of captions containing 'holding-verbs' and 'container-nouns' compared to images displaying telic affordance. Perceptual Salience, Object Number, and ENA are also associated with the choice of linguistic expressions. Our study demonstrates that comprehensive understanding of objects or events requires cognitive attention, semantic nuances in language, and integration across multiple modalities. We highlight the vital importance of situated meaning and affordance grounding in natural language understanding, with the potential to advance human-like interpretation in various scenarios.Comment: 10 pages, 9 figure

    Dark Matter with multi-annihilation channels and AMS-02 positron excess and antiproton

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    Abstract AMS-02 provided the unprecedented statistics in the measurement of the positron fraction from cosmic rays. That may offer a unique opportunity to distinguish the positron spectrum coming from various dark matter (DM) annihilation channels, if DM is the source of this positron excess. Therefore, we consider the scenario that the DM can annihilate into leptonic, quark, and massive gauge boson channels simultaneously with floating branching ratios to test this hypothesis. We also study the impacts from MAX, MED, MIN, and DC diffusion models as well as from isothermal, NFW, and Einasto DM density profiles on our results. We found two parameter regions that can satisfy both AMS-0

    Microstructure and superelastic properties of FeNiCoAlTi single crystals with the <100> orientation under tension

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    The microstructure and superelastic response of an Fe41 Ni28 Co17 Al11.5 Ti2.5 (at.%) single crystal along the [removed] orientation was investigated under tension at room temperature after aging at 600◦ C for 24 h. From the superelastic results, the samples aged at 600◦ C for 24 h exhibited 4.5% recoverable strain at room temperature. The digital image correlation (DIC) method was used to observe the strain distribution during the 6.5% applied strain loading. The DIC results showed that the strain was uniformly distributed during the loading and unloading cycles. Only one martensite variant was observed from the DIC results. This was related to the aging heat treatment times. The martensite morphology became a single variant with a longer aging time. The thermo-magnetization results indicated that the phase transformation and temperature hysteresis was around 36◦ C. Increasing the magnetic field from 0.05 to 7 Tesla, the transformation temperatures increased. The maximum magnetization was 160 emu/g under the magnetic field of 7 Tesla. From the transmission electron microscopy results, the L12 precipitates were around 10 nm in size, and they were high in Ni content and low in Fe content

    Understanding the performance of thin-client gaming

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    Abstract—The thin-client model is considered a perfect fit for online gaming. As modern games normally require tremendous computing and rendering power at the game client, deploying games with such models can transfer the burden of hardware upgrades from players to game operators. As a result, there are a variety of solutions proposed for thin-client gaming today. However, little is known about the performance of such thin-client systems in different scenarios, and there is no systematic means yet to conduct such analysis. In this paper, we propose a methodology for quantifying the performance of thin-clients on gaming, even for thin-clients which are close-sourced. Taking a classic game, Ms. Pac-Man, and three popular thin-clients, LogMeIn, TeamViewer, and UltraVNC, as examples, we perform a demonstration study and determine that 1) display frame rate and frame distortion are both critical to gaming; and 2) different thin-client implementations may have very different levels of robustness against network impairments. Generally, LogMeIn performs best when network conditions are reasonably good, while TeamViewer and UltraVNC are the better choices under certain network conditions. I
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