147 research outputs found

    Seismic pushover analysis of steel integral abutment bridge

    Get PDF
    Integral abutment bridges (IABs) have a continuous deck monolithically encased into abutment stem. A lack of information on their seismic design and performance may discouraged their usage in high seismic zones. In this study, current research and implementation of IABs are comprehensively reviewed. The properties and typical construction details are presented. Three real-life IABs with steel-concrete girders provided by NYDOT are chosen as prototypes for intensive seismic study. Three-dimensional finite element models of IABs for nonlinear seismic analysis are elaborated to capture the behavior of components of steel-concrete superstructure, abutment stem, piles, backfill, etc. Pushover analyses are carried out to obtain the capacity curve. To evaluate the seismic performance of the three IABs, capacity spectrum method from the ATC-40 specification is studied and executed by CSibridge@ software. By parametric studies, the effects of bearing and skew are outlined. Conclusions and some recommendations are made for seismic evaluation and design practice

    Language Models as Inductive Reasoners

    Full text link
    Inductive reasoning is a core component of human intelligence. In the past research of inductive reasoning within computer science, formal language is used as representations of knowledge (facts and rules, more specifically). However, formal language can cause systematic problems for inductive reasoning such as disability of handling raw input such as natural language, sensitiveness to mislabeled data, and incapacity to handle ambiguous input. To this end, we propose a new paradigm (task) for inductive reasoning, which is to induce natural language rules from natural language facts, and create a dataset termed DEER containing 1.2k rule-fact pairs for the task, where rules and facts are written in natural language. New automatic metrics are also proposed and analysed for the evaluation of this task. With DEER, we investigate a modern approach for inductive reasoning where we use natural language as representation for knowledge instead of formal language and use pretrained language models as ''reasoners''. Moreover, we provide the first and comprehensive analysis of how well pretrained language models can induce natural language rules from natural language facts. We also propose a new framework drawing insights from philosophy literature for this task, which we show in the experiment section that surpasses baselines in both automatic and human evaluations. We discuss about our future perspectives for inductive reasoning in Section 7. Dataset and code are available at https://github.com/ZonglinY/Inductive_Reasoning.Comment: Accepted by EACL 202

    What chemical species are responsible for new particle formation and growth in the Netherlands? A hybrid positive matrix factorization (PMF) analysis using aerosol composition (ACSM) and size (SMPS)

    Get PDF
    Aerosol formation acts as a sink for gas-phase atmospheric species that controls their atmospheric lifetime and environmental effects. To investigate aerosol formation and evolution in the Netherlands, a hybrid positive matrix factorization (PMF) analysis was conducted using observations from May, June, and September 2021 collected in the rural site of Cabauw in the central part of the Netherlands. The hybrid input matrix consists of the full organic mass spectrum acquired from a time-of-flight aerosol chemical speciation monitor (ToF-ACSM), ACSM inorganic species concentrations, and binned particle size distribution concentrations from a scanning mobility particle sizer (SMPS). These hybrid PMF analyses discerned four factors that describe aerosol composition variations: two size-driven factors that are related to new particle formation (NPF) and growth (F4 and F3), as well as two bulk factors driven by composition, not size (F2 and F1). The distribution of chemical species across these factors shows that different compounds are responsible for nucleation and growth of new particles. The smallest-diameter size factor (F4) contains ammonium sulfate and organics and typically peaks during the daytime. Newly formed particles, represented by F4, are mainly correlated with wind from the southwesterly-westerly and easterly sectors that transport sulfur oxides (SOx), ammonia (NH3), and organic precursors to Cabauw. As the particles grow from F4 to F3 and to bulk factors, nitrate and organics play an increasing role, and the particle loading diurnal cycle shifts from daytime to a nighttime maximum. Greater organics availability makes secondary organic aerosol (SOA) more influential in summertime aerosol growth, principally due to volatility differences produced by seasonal variation in photooxidation and temperature.</p

    SREBP-1a activation by HBx and the effect on hepatitis B virus enhancer II/core promoter

    Get PDF
    Hepatitis B virus (HBV) X protein (HBx) plays an important role in HBV pathogenesis by regulating gene expression. Sterol regulatory element binding protein-1a (SREBP-1a) is a key transcriptional factor for modulating fatty acid and cholesterol synthesis. Here we demonstrated that HBx increased mature SREBP-1a protein level in the nucleus and its activity as a transcription factor. We further showed that the up-regulation of SREBP-1a by HBx occurred at the transcriptional level after ectopic expression and in the context of HBV replication. Deletional analysis using SREBP-1a promoter revealed that the sequence from -436 to -398 in the promoter was required for its activation by HBx. This promoter region possesses the binding sequences for two basic leucine zipper (b-ZIP) transcription factors, namely C/EBP and E4BP4. Mutagenesis of the binding sequences on the SREBP-1a promoter and ectopic expression experiments demonstrated that C/EBPα enhanced SREBP-1a activation by HBx, while E4BP4 had an inhibitory effect. C/EBPα was able to significantly reverse the inhibitory activity of E4BP4 on SREBP-1a promoter. These results demonstrated that HBx activates SREBP-1a activity at the transcription level through a complex mechanism involving two bZIP transcription factors C/EBP and E4BP4 with C/EBP being the dominant positive factor. Finally, we showed that knocking down SREBP-1 abolishes HBV enhancer II/core promoter activation by HBx.Fil: Qiao, Ling. University Of Saskatchewan; CanadáFil: Wu, Qi. University Of Saskatchewan; CanadáFil: Lu, Xinya. University Of Saskatchewan; CanadáFil: Zhou, Yan. University Of Saskatchewan; CanadáFil: Fernández Alvarez, Ana Julia. Consejo Superior de Investigaciones Cientificas; España. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquímicas de Buenos Aires. Fundación Instituto Leloir. Instituto de Investigaciones Bioquímicas de Buenos Aires; ArgentinaFil: Ye, Lihong. Nankai University; ChinaFil: Zhang, Xiaodong. Nankai University; ChinaFil: Han, Jihong. Nankai University; ChinaFil: Casado, Marta. Consejo Superior de Investigaciones Cientificas; EspañaFil: Liu, Quiang. University Of Saskatchewan; Canad

    Reconstruction of global gridded monthly sectoral water withdrawals for 1971-2010 and analysis of their spatiotemporal patterns

    Get PDF
    Human water withdrawal has increasingly altered the global water cycle in past decades, yet our understanding of its driving forces and patterns is limited. Reported historical estimates of sectoral water withdrawals are often sparse and incomplete, mainly restricted to water withdrawal estimates available at annual and country scale, due to a lack of observations at local and seasonal time scales. In this study, through collecting and consolidating various sources of reported data and developing spatial and temporal statistical downscaling algorithms, we reconstruct a global monthly gridded (0.5 degree) sectoral water withdrawal dataset for the period 1971–2010, which distinguishes six water use sectors, i.e. irrigation, domestic, electricity generation (cooling of thermal power plants), livestock, mining, and manufacturing. Based on the reconstructed dataset, the spatial and temporal patterns of historical water withdrawal are analyzed. Results show that global total water withdrawal has increased significantly during 1971–2010, mainly driven by the increase of irrigation water withdrawal. Regions with high water withdrawal are those densely populated or with large irrigated cropland production, e.g., the United States (US), eastern China, India, and Europe. Seasonally, irrigation water withdrawal in summer for the major crops contributes a large percentage of annual total irrigation water withdrawal in mid and high-latitude regions, and the dominant season of irrigation water withdrawal is also different across regions. Domestic water withdrawal is mostly characterized by a summer peak, while water withdrawal for electricity generation has a winter peak in high-latitude regions and a summer peak in low-latitude regions. Despite the overall increasing trend, irrigation in the western US and domestic water withdrawal in western Europe exhibit a decreasing trend. Our results highlight the distinct spatial pattern of human water use by sectors at the seasonal and annual scales. The reconstructed gridded water withdrawal dataset is open-access, and can be used for examining issues related to water withdrawals at fine spatial, temporal and sectoral scales

    What chemical species are responsible for new particle formation and growth in the Netherlands? A hybrid positive matrix factorization (PMF) analysis using aerosol composition (ACSM) and size (SMPS)

    Get PDF
    Aerosol formation acts as a sink for gas-phase atmospheric species that controls their atmospheric lifetime and environmental effects. To investigate aerosol formation and evolution in the Netherlands, a hybrid positive matrix factorization (PMF) analysis has been conducted using observations from May, June, and September 2021 collected in a rural site of Cabauw in Central Netherlands. The hybrid input matrix consists of the full organic mass spectrum acquired from a time-of-flight aerosol chemical speciation monitor (ToF-ACSM), ACSM species concentrations, and binned particle size distribution concentrations from a scanning mobility particle sizer (SMPS). These hybrid PMF analyses discerned six factors that describe aerosol composition variations: four size-driven factors that are related to new particle formation and growth (F6, F5, F4, and F3), and two bulk factors driven by composition, not size (F2, F1). The smallest-diameter size factor (F6) contains ammonium sulfate and organics, and typically occurs during the daytime. Newly formed particles, represented by F6, are correlated with wind from the southwesterly-westerly, northerly, and easterly sectors that transport sulfur oxides (SOx), ammonia (NH3), and organic precursors to Cabauw. As the particles grow from F6 to F3, nitrate plays an increasing role, and the particle loading diurnal cycle shifts from daytime to a nighttime maximum. The inorganic ion balance and organics composition in the bulk atmosphere affects the chemical composition variation across factors and seasons. Changing ammonium-sulfate-nitrate equilibrium shifts inorganic species among factors, and greater organics availability makes secondary organic aerosol (SOA) more influential in summertime aerosol growth, principally due to volatility differences produced by seasonal variation in photooxidation and temperature

    A Global Hydrologic Framework to Accelerate Scientific Discovery

    Get PDF
    With the ability to simulate historical and future global water availability on a monthly time step at a spatial resolution of 0.5 geographic degree, the Python package Xanthos version 1 provided a solid foundation for continuing advancements in global water dynamics science. The goal of Xanthos version 2 was to build upon previous investments by creating a Python framework where core components of the model (potential evapotranspiration (PET), runoff generation, and river routing) could be interchanged or extended without having to start from scratch. Xanthos 2 utilizes a component-style architecture which enables researchers to quickly incorporate and test cutting-edge research in a stable modeling environment prebuilt with diagnostics. Major advancements for Xanthos 2 were also achieved by the creation of a robust default configuration with a calibration module, hydropower modules, and new PET modules, which are now available to the scientific community. Funding statement: This research was supported by the U.S. Department of Energy, Office of Science, as part of research in Multi-Sector Dynamics, Earth and Environmental System Modeling Program. The Pacific Northwest National Laboratory is operated for DOE by Battelle Memorial Institute under contract DE-AC05-76RL01830. The views and opinions expressed in this paper are those of the authors alone

    Fano resonance engineering in mirror-symmetry-broken THz metamaterials

    Get PDF
    We introduce a comprehensive approach to the design of mirror-symmetry broken terahertz (THz) metamaterials and present both the simulation and experimental results which show the desired asymmetric Fano resonances and electromagnetic induced transparency (EIT)-like windows. With a full wave simulation, we find these asymmetry-induced resonance modes possess extremely high quality factors and they broaden with increase of the structure asymmetry. This phenomenon arises from the destructive interference of a super-radiative bright mode and a sub-radiative dark mode which can’t be excited directly. Surface current and electric field distributions are analyzed to explain the emergence of these Fano resonances. An intuitive mechanical coupled oscillator model is derived to explain the unique line-shape of such Fano resonances. Moreover, large resonant frequency tuning (50 GHz) of Fano resonance has been demonstrated by temperature induced phase change in liquid crystals. We believe that the Fano resonance in THz metamaterials may serve as a strong building block for passive or active THz elements with potential applications for future detection and sensing systems and devices.The authors would like to thank the UK Engineering and Physical Sciences Research Council (EPSRC) for the support through the Platform Grant for Liquid Crystal Photonics (EP/F00897X/1). Xuefeng Li would like to acknowledge the support from Cambridge Trust.This is the author accepted manuscript. It is currently under an indefinite embargo pending publication by Springer

    An analysis of digital marketing strategy in the era of social media in China

    No full text
    This thesis analyzes digital marketing strategies in the era of social media in China. With the development of information technology, the gradual stabilization of China's economic growth, and the catalysis of the epidemic, advertisers need to achieve breakthroughs through more effective marketing strategies. The rise of social media undoubtedly provides opportunities. This thesis will focus on the three digital marketing strategies: content marketing, live streaming e-commerce, and trust fission. As a marketing method that has existed since the paper media era, content marketing has been given new meanings in the social media era. In Chapter 2, this article goes back to the history of content marketing and proposes how to design content marketing based on the characteristics of content marketing in the era of social media, as well as case analysis. With the development of 4G technology and the gradual commercialization of 5G, the importance of live broadcasting has become increasingly prominent. This thesis analyzes e-commerce live streaming in Chapter3. Live streaming e-commerce is a recombination of the three elements of traditional BtoC: people, goods, and fields. Meanwhile, live streaming can use various methods to encourage consumers to make purchases during the live streaming, thereby generating a large number of instant transactions. The author points out in Chapter 4 that as centralized public domain net flow becomes increasingly expensive, advertisers urgently need to consider building and operating private domain traffic. Social media's social and media attributes are the natural platform for building private domain traffic pools, and trust fission is the key to building traffic pools and further operations. In Chapter 5, the author pointed out that the widespread influence of social media determines that the use of social media marketing does not need to prioritize the target population but achieves a wide range of influence by evaluating the demands of businesses and increasing the topicality of the advertising. Social media are characterized by the integration of sales and marketing, especially in e-commerce live streaming. The marketing strategy at this stage is decentralized.S.M
    • …
    corecore