958 research outputs found

    Results on heavy ion collisions at LHCb

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    Heavy flavor production is important in heavy ion collisions to study both cold and hot nuclear matter effects. The LHCb experiment can make unique contribution to heavy ion physics, owing to the full particle identification of the detector in the forward region and the ability to collect fixed target data with proton or lead beams. This report describes recent results with proton-lead collision data collected in 2013 and the prospect of heavy-ion studies at LHCb.Comment: Proceeding for "Rencontres de Moriond QCD and High Energy Interactions

    The influence of conjugation in molecular tunneling junctions and nanofabrication

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    An Empirical Study on the Relationship between Entrepreneur’s Reputation and Financing Constraints

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    Information asymmetry is an important reason that causes external financing constraints. Because reputation has the function of signal transmission, a better reputation of an entrepreneur can reduce the degree of the firm information asymmetry and alleviate financing constraints of the firm. Based on the grouped sample of 94 listed companies of China from 2007 to 2009, this paper did empirical study on the relationship between entrepreneur’s reputation and financing constraints. The results show that entrepreneur’s reputation has a significant effect on firm financing activity. In other words, higher entrepreneur’s reputation leads to lower financing constraints. This study has a significant impact in helping managers and investors realize the importance of signaling effect of a good reputation in capital market. Meanwhile, it helps motivate entrepreneurs to establish good reputation, increasing the efficiency of capital market

    From Simple to Complex: A Progressive Framework for Document-level Informative Argument Extraction

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    Document-level Event Argument Extraction (EAE) requires the model to extract arguments of multiple events from a single document. Considering the underlying dependencies between these events, recent efforts leverage the idea of "memory", where the results of already predicted events are cached and can be retrieved to help the prediction of upcoming events. These methods extract events according to their appearance order in the document, however, the event that appears in the first sentence does not mean that it is the easiest to extract. Existing methods might introduce noise to the extraction of upcoming events if they rely on an incorrect prediction of previous events. In order to provide more reliable memory, we propose a simple-to-complex progressive framework for document-level EAE. Specifically, we first calculate the difficulty of each event and then, we conduct the extraction following a simple-to-complex order. In this way, the memory will store the most certain results, and the model could use these reliable sources to help the prediction of more difficult events. Experiments on WikiEvents show that our model outperforms SOTA by 1.4% in F1, indicating the proposed simple-to-complex framework is useful in the EAE task.Comment: Accepted to the Findings of EMNLP 2023 (Long Paper

    The influence of conjugation in molecular tunneling junctions and nanofabrication

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    The influence of conjugation in molecular tunneling junctions and nanofabrication

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    Het doel van dit proefschrift is om de tunneling-eigenschappen van grote-oppervlakte moleculaire juncties bestaande uit zelforganiserende monolagen (SAMs) van geconjugeerde, organische moleculen met verschillende conjugatiepatronen te onderzoeken en deze te integreren in drie-terminale juncties, met als doel het transport van lading middels tunneling te sturing met elektrische velden. In Moleculaire Electronica is het van belang om te begrijpen hoe conjugatie patronen, het transport van lading middels tunneling beĂŻnvloeden. Eerst hebben we de eigenschappen van zelforganiserende monolagen bestaande uit oliothiopheenquarterthiopheen met een flexibele butaanthiolstaart bestudeerd met behulp van CP-AFM en EgaIn en vonden dat de SAMs, mechanisch en elektrisch robuust waren. Daarna hebben we drie moleculaire draden gebaseerd op benzodithiopheen gesynthetiseerd. We hebben het tunneling-ladingstransport van de grote-oppervlakte moleculaire juncties bestaande uit deze benzodithiopheenderivaten bestudeerd en vergeleken met het bekende anthraquinone. De quinone functionele groep introduceert niet alleen kruisconjugatie, maar remt ook het tunneling transport vanwege zijn elektronegativiteit. Later hebben we geprobeerd om organische moleculen in te bouwen in nano-gap tunneling juncties met behulp van nanoskiving, we noemen deze SAM-templated addressable nanogap electrodes (STANs). We beschreven onze inspanningen tot het fabriceren van solid-state apparaten, bevattende moleculaire tunneling juncties. Het laatste deel omvat de fabricatie van uiterst lange, vrijstaande goud nanodraden met behulp van nanoskiving. Twee toepassingen van deze goud nanodraden zijn gedemonstreerd: ten eerste als een hetedraads anemometer om de stroomsnelheid te meten door middel van de weerstand over de goud nanodraad; en ten tweede voor het oprekken van DNA moleculen in de stroom om ze te visualiseren met fluorescentiemicroscopie

    Representation and Matching of Articulated Shapes

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    We consider the problem of localizing the articulated and deformable shape of a walking person in a single view. We represent the non-rigid 2D body contour by a Bayesian graphical model whose nodes correspond to point positions along the contour. The deformability of the model is constrained by learned priors corresponding to two basic mechanisms: local non-rigid deformation, and rotation motion of the joints. Four types of image cues are combined to relate the model configuration to the observed image, including edge gradient map, foreground/background mask, skin color mask, and appearance consistency constraints. The constructed Bayes network is sparse and chain-like, enabling efficient spatial inference through Sequential Monte Carlo sampling methods. We evaluate the performance of the model on images taken in cluttered, outdoor scenes. The utility of each image cue is also empirically explored

    A scheme to fix multiple solutions in amplitude analyses

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    Decays of unstable heavy particles usually involve the coherent sum of several amplitudes, like in a multiple slit experiment. Dedicated amplitude analysis techniques have been widely used to resolve these amplitudes for better understanding of the underlying dynamics. For special cases, where two spin-1/2 particles and two (pseudo-)scalar particles are present in the process, multiple equivalent solutions are found due to intrinsic symmetries in the summed probability density function. In this paper, the problem of multiple solutions is discussed and a scheme to overcome this problem is proposed by fixing some free parameters. Toys are generated to validate the strategy. A new approach to align helicities of initial- and final-state particles in different decay chains is also introduced.Comment: 17 pages, 2 figure
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