1,332 research outputs found

    National corridors for climate change mitigation: managing industrial CO2 emissions in France

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    International audiencePlanning for the deployment of carbon dioxide capture and storage (CCS), infrastructure must consider numerous uncertainties regarding where and how much CO2 is produced and where captured CO2 can be geologically stored. We used the SimCCS engineering-economic geospatial optimization models to determine the characteristics of CCS deployment in France and corridors for pipelines that are robust to a priori uncertainty in CO2 production from industrial sources and CO2 storage locations. We found a number of stable routes that are robust to these uncertainties, and thus can provide early options for pipeline planning and rights-of-way acquisition

    LayoutLM: Pre-training of Text and Layout for Document Image Understanding

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    Pre-training techniques have been verified successfully in a variety of NLP tasks in recent years. Despite the widespread use of pre-training models for NLP applications, they almost exclusively focus on text-level manipulation, while neglecting layout and style information that is vital for document image understanding. In this paper, we propose the \textbf{LayoutLM} to jointly model interactions between text and layout information across scanned document images, which is beneficial for a great number of real-world document image understanding tasks such as information extraction from scanned documents. Furthermore, we also leverage image features to incorporate words' visual information into LayoutLM. To the best of our knowledge, this is the first time that text and layout are jointly learned in a single framework for document-level pre-training. It achieves new state-of-the-art results in several downstream tasks, including form understanding (from 70.72 to 79.27), receipt understanding (from 94.02 to 95.24) and document image classification (from 93.07 to 94.42). The code and pre-trained LayoutLM models are publicly available at \url{https://aka.ms/layoutlm}.Comment: KDD 202

    On the Bright Side of Darkness: Side-Channel Based Authentication Protocol Against Relay Attacks

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    Relay attacks are nowadays well known and most designers of secure authentication protocols are aware of them. At present, the main methods to prevent these attacks are based on the so-called distance bounding technique which consists in measuring the round-trip time of the exchanged authentication messages between the prover and the verifier to estimate an upper bound on the distance between these entities. Based on this bound, the verifier checks if the prover is sufficiently close by to rule out an unauthorized entity. Recently, a new work has proposed an authentication protocol that surprisingly uses the side-channel leakage to prevent relay attacks. In this paper, we exhibit some practical and security issues of this protocol and provide a new one that fixes all of them. Then, we argue the resistance of our proposal against both side-channel and relay attacks under some realistic assumptions. Our experimental results show the efficiency of our protocol in terms of false acceptance and false rejection rates

    Socio-Cultural Factors Challenging Development Interventions in Cattle Production in the Remote Areas of Vietnam

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    The northwest highlands of Vietnam are characterized by high altitude, low infrastructure, and low population densities composed of a wide diversity of different ethnic groups. Their socio-cultural characteristics strongly influence their lifestyle and production systems, including agricultural activities. The majority of these people have suffered from slow economic development, with the highest poverty rate in the country. This is a real need for plausible interventions where behavioral changes of smallholders throughout local value chains would be a critical foundation. Our project implemented in this context of development in the Northwest highlands of Vietnam aims to understand the role of socio-cultural factors in cattle production systems in order to propose and examine feasible technical and marketing interventions to improve local grazing-based cattle production. Data on farmers and other actors (collectors, slaughterhouses, retailers and consumers) in local cattle value chains of two selected provinces (Son La and Dien Bien) were collected at the beginning of the project via a baseline survey. In addition, different group discussions with farmers were conducted until the end of the project to monitor the project’s progress and changes created through its interventions. We found that such behavioral changes cannot be motivated by development interventions per se without integrating an understanding of socio-cultural factors (i.e. ethnicity, geographical location and grazing-practices)

    A giant comet-like cloud of hydrogen escaping the warm Neptune-mass exoplanet GJ 436b

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    Exoplanets orbiting close to their parent stars could lose some fraction of their atmospheres because of the extreme irradiation. Atmospheric mass loss primarily affects low-mass exoplanets, leading to suggest that hot rocky planets might have begun as Neptune-like, but subsequently lost all of their atmospheres; however, no confident measurements have hitherto been available. The signature of this loss could be observed in the ultraviolet spectrum, when the planet and its escaping atmosphere transit the star, giving rise to deeper and longer transit signatures than in the optical spectrum. Here we report that in the ultraviolet the Neptune-mass exoplanet GJ 436b (also known as Gliese 436b) has transit depths of 56.3 +/- 3.5% (1 sigma), far beyond the 0.69% optical transit depth. The ultraviolet transits repeatedly start ~2 h before, and end >3 h after the ~1 h optical transit, which is substantially different from one previous claim (based on an inaccurate ephemeris). We infer from this that the planet is surrounded and trailed by a large exospheric cloud composed mainly of hydrogen atoms. We estimate a mass-loss rate in the range of ~10^8-10^9 g/s, which today is far too small to deplete the atmosphere of a Neptune-like planet in the lifetime of the parent star, but would have been much greater in the past.Comment: Published in Nature on 25 June 2015. Preprint is 28 pages, 12 figures, 2 table

    Distributions of epistasis in microbes fit predictions from a fitness landscape model.

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    How do the fitness effects of several mutations combine? Despite its simplicity, this question is central to the understanding of multilocus evolution. Epistasis (the interaction between alleles at different loci), especially epistasis for fitness traits such as reproduction and survival, influences evolutionary predictions "almost whenever multilocus genetics matters". Yet very few models have sought to predict epistasis, and none has been empirically tested. Here we show that the distribution of epistasis can be predicted from the distribution of single mutation effects, based on a simple fitness landscape model. We show that this prediction closely matches the empirical measures of epistasis that have been obtained for Escherichia coli and the RNA virus vesicular stomatitis virus. Our results suggest that a simple fitness landscape model may be sufficient to quantitatively capture the complex nature of gene interactions. This model may offer a simple and widely applicable alternative to complex metabolic network models, in particular for making evolutionary predictions

    Haldane's rule in the 21st century

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    Haldane's Rule (HR), which states that 'when in the offspring of two different animal races one sex is absent, rare, or sterile, that sex is the heterozygous (heterogametic) sex', is one of the most general patterns in speciation biology. We review the literature of the past 15 years and find that among the similar to 85 new studies, many consider taxa that traditionally have not been the focus for HR investigations. The new studies increased to nine, the number of 'phylogenetically independent' groups that comply with HR. They continue to support the dominance and faster-male theories as explanations for HR, although due to increased reliance on indirect data (from, for example, differential introgression of cytoplasmic versus chromosomal loci in natural hybrid zones) unambiguous novel results are rare. We further highlight how research on organisms with sex determination systems different from those traditionally considered may lead to more insight in the underlying causes of HR. In particular, haplodiploid organisms provide opportunities for testing specific predictions of the dominance and faster X chromosome theory, and we present new data that show that the faster-male component of HR is supported in hermaphrodites, suggesting that genes involved in male function may evolve faster than those expressed in the female function. Heredity (2011) 107, 95-102; doi:10.1038/hdy.2010.170; published online 12 January 201

    Development of an Acute and Highly Pathogenic Nonhuman Primate Model of Nipah Virus Infection

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    Nipah virus (NiV) is an enigmatic emerging pathogen that causes severe and often fatal neurologic and/or respiratory disease in both animals and humans. Amongst people, case fatality rates range between 40 and 75 percent and there are no vaccines or treatments approved for human use. Guinea pigs, hamsters, cats, ferrets, pigs and most recently squirrel monkeys (New World monkey) have been evaluated as animal models of human NiV infection, and with the exception of the ferret, no model recapitulates all aspects of NiV-mediated disease seen in humans. To identify a more viable nonhuman primate (NHP) model, we examined the pathogenesis of NiV in African green monkeys (AGM). Exposure of eight monkeys to NiV produced a severe systemic infection in all eight animals with seven of the animals succumbing to infection. Viral RNA was detected in the plasma of challenged animals and occurred in two of three subjects as a peak between days 7 and 21, providing the first clear demonstration of plasma-associated viremia in NiV experimentally infected animals and suggested a progressive infection that seeded multiple organs simultaneously from the initial site of virus replication. Unlike the cat, hamster and squirrel monkey models of NiV infection, severe respiratory pathology, neurological disease and generalized vasculitis all manifested in NiV-infected AGMs, providing an accurate reflection of what is observed in NiV-infected humans. Our findings demonstrate the first consistent and highly pathogenic NHP model of NiV infection, providing a new and critical platform in the evaluation and licensure of either passive and active immunization or therapeutic strategies for human use
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