26 research outputs found

    A Unified Pre-training and Adaptation Framework for Combinatorial Optimization on Graphs

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    Combinatorial optimization (CO) on graphs is a classic topic that has been extensively studied across many scientific and industrial fields. Recently, solving CO problems on graphs through learning methods has attracted great attention. Advanced deep learning methods, e.g., graph neural networks (GNNs), have been used to effectively assist the process of solving COs. However, current frameworks based on GNNs are mainly designed for certain CO problems, thereby failing to consider their transferable and generalizable abilities among different COs on graphs. Moreover, simply using original graphs to model COs only captures the direct correlations among objects, which does not consider the mathematical logicality and properties of COs. In this paper, we propose a unified pre-training and adaptation framework for COs on graphs with the help of the maximum satisfiability (Max-SAT) problem. We first use Max-SAT to bridge different COs on graphs since they can be converted to Max-SAT problems represented by standard formulas and clauses with logical information. Then, we further design a pre-training and domain adaptation framework to extract the transferable and generalizable features so that different COs can benefit from them. In the pre-training stage, Max-SAT instances are generated to initialize the parameters of the model. In the fine-tuning stage, instances from CO and Max-SAT problems are used for adaptation so that the transferable ability can be further improved. Numerical experiments on several datasets show that features extracted by our framework exhibit superior transferability and Max-SAT can boost the ability to solve COs on graphs

    Comparison of live microalgae and Spray-dried algae powder effects on growth, digestive and antioxidant capacity of juvenile pearl oyster <em>Pinctada maxima</em>

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    The pearl production through the pearl oyster *Pinctada maxima's* culture has developed slowly over the past decades due to over-fishing of wild populations and mass mortality at juvenile stages. Indoor farming is an alternative mode for *P. maxima* juvenile cultivation to improve survival rates. In pursuit of optimizing healthy management under the indoor farming mode, the objective of this investigation was to compare the growth performance, digestion, and antioxidant capacity of juveniles fed with different microalgae-based diets (live *Isochrysis zhanjiangensis,* *Platymonas subcordiformis*, *Chaetoceros muelleri*; and spray-dried *I. zhanjiangensis*, *P. subcordiformis*, *C. muelleri* powder). The juvenile survival rates fed with spray-dried microalgae powder (except *C. muelleri* powder) were not significantly different from those fed on live microalgae. However, the growth performance of juveniles fed with spray-dried microalgae powder could have been better than the live one. The digestive enzymatic activities were consistent with growth performance, and diets affected the antioxidant capacity. The spray-dried *I. zhanjiangensis* powder can serve as a substitute for live microalga in *P. maxima* juvenile indoor farming and is recommended under controlled conditions. The findings from this study would provide essential data to improve health management for *P. maxima* juveniles in indoor farming conditions

    A nanozyme tag enabled chemiluminescence imaging immunoassay for multiplexed cytokine monitoring

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    We report a new concept of a chemiluminescence imaging nanozyme immunoassay (CINIA), in which nanozymes are exploited as catalytic tags for simultaneous multiplex detection of cytokines. The CINIA provides a novel and universal nanozyme-labeled multiplex immunoassay strategy for high-throughput detection of relevant biomarkers and further disease diagnosis

    A nanozyme tag enabled chemiluminescence imaging immunoassay for multiplexed cytokine monitoring

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    We report a new concept of a chemiluminescence imaging nanozyme immunoassay (CINIA), in which nanozymes are exploited as catalytic tags for simultaneous multiplex detection of cytokines. The CINIA provides a novel and universal nanozyme-labeled multiplex immunoassay strategy for high-throughput detection of relevant biomarkers and further disease diagnosis

    Dynamics of heterotrophic dinoflagellates off the Pearl River Estuary, northern South China Sea

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    Variations in abundance, biomass, vertical profile and cell size of heterotrophic dinoflagellates (HDFs) between summer and winter and its controlling factors were studied in the northern South China Sea (SCS). It was found that HDF abundance and carbon biomass were 4-102 x 10(3) cells L-1 and 0.34-12.3 mg C L-1 in winter (February 2004), respectively, while they were 2-142 x 10(3) cells L-1 and 0.22-31.4 mu g C L-1 in summer (July, 2004), respectively, in the northern SCS. HDF abundance and carbon biomass decreased from the estuary to inshore and then offshore. Vertical profiles of HDF abundance were heterogeneous, which accorded well with that of chlorophyll a (Chl.a). Higher abundance of HDFs was often observed at a depth of 30-70 m offshore waters, matching well with the Chl.a maximum, while it showed high abundance at the surface in some coastal and estuary stations. Small HDFs (20 mu m) generally contributed equally in terms of carbon biomass, accounting for 47% on average. HDFs showed different variation patterns for the different study regions; in the estuarine and continental shelf regions, abundance and biomass values were higher in summer than those in winter, while it was the reverse pattern for the slope waters. Hydrological factors (e.g. water mass, river outflow, monsoon and eddies) associated with biological factors, especially the size-fractionated Chl.a, seemed to play an important role in regulating HDF distribution and variations in the northern South China Sea. (C) 2009 Elsevier Ltd. All rights reserved.China NSF [40730846, 40806058, 90711006]; Ministry of Science and Technology of China [2006CR400604

    Draft genome sequence of the Tibetan antelope

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    The Tibetan antelope (Pantholops hodgsonii) is endemic to the extremely inhospitable high-altitude environment of the Qinghai-Tibetan Plateau, a region that has a low partial pressure of oxygen and high ultraviolet radiation. Here we generate a draft genome of this artiodactyl and use it to detect the potential genetic bases of highland adaptation. Compared with other plain-dwelling mammals, the genome of the Tibetan antelope shows signals of adaptive evolution and gene-family expansion in genes associated with energy metabolism and oxygen transmission. Both the highland American pika, and the Tibetan antelope have signals of positive selection for genes involved in DNA repair and the production of ATPase. Genes associated with hypoxia seem to have experienced convergent evolution. Thus, our study suggests that common genetic mechanisms might have been utilized to enable high-altitude adaptation

    Layered Double Hydroxide-Based Photocatalysts for the Removal of Emerging Contaminants: Progress in Past Ten Years

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    Currently, public health is seriously threatened by the massive concentrations of emerging contaminants. Treating emerging contaminants in water using effective methods has become a major challenge worldwide. Photocatalytic technology, as an eco-friendly technology, has been recognized as an effective means of removing contaminants from water. Among the various photocatalysts, layered double hydroxides (LDHs), known as hydrotalcite-like materials, have been explored extensively in photocatalytic reactions due to their switchable properties and the large surface areas of their unique two-dimensional structures. In this article, recent advances in the photocatalytic degradation of emerging contaminants by LDH-based photocatalysts are reviewed. Firstly, the fundamental principles of the photocatalytic degradation of emerging contaminants using LDH-based materials are briefly introduced. Various LDHs applied in the photocatalytic degradation of emerging contaminants are broadly summarized into four types: pure-phase LDHs, interlayer-modified LDHs, LDH-based composites, and layered double oxides (LDOs). Moreover, the synthesis process and catalytic mechanism of LDH-based photocatalysts are also reviewed. An outlook on the problems and future development of LDH-based photocatalysts in water remediation is provided at the end

    Spatial and temporal distribution of nanoflagellates in the northern South China Sea

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    Seasonal variation, horizontal and vertical distribution, and cell size of nanoflagellates, together with physico-chemical and biological factors, were studied in the northern South China Sea (SCS). It was found that nanoflagellate abundance ranged from 0.157 x 10(3) to 9.193 x 10(3) cells/ml (with a mean of 0.891 x 10(3)) in winter (February, 2004), while it ranged from 0.107 x 10(3) to 5.417 x 10(3) cells/ml (with a mean of 0.599 x 10(3)) in summer (July, 2004). Nanoflagellates were more abundant in winter than summer in offshore regions, showing an unique seasonal pattern in this subtropical marginal sea. The abundance of nanoflagellates decreased from the estuary to the offshore region. Vertical distribution of nanoflagellates coupled well with that of bacteria and Chl a. The small size fraction of less than 5 mu m dominated the nanoflagellate populations. Wind-driven mixing, eddies, availability of nutrients as well as Chl a and abundance of picoplankton seemed to be the major controlling factors for the spatial distribution and seasonal variation of nanoflagellates in the study area

    Enhanced Stability and Mobility of Solution-Processed Oxide Thin-Film Transistors with Bilayer Terbium-incorporated Indium Oxide Channel

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    The trade-off between mobility and stability in oxide thin-film transistors (TFTs) hinders further advances of active-matrix flat panel display. Herein, a solution-processed bilayer active channel is designed to improve the stability and mobility simultaneously. The optical bandgap and work function of Tb:In2O3 films are modulated by tuning the films thickness and Tb concentration of Tb-doped indium oxide (Tb:In2O3) films. Large conduction band offset is achieved in Tb:In2O3 bilayer channel, which induces accumulation of abundant electrons at the interface. The mobility is significantly improved to 38.2 cm2/Vs, and the photoinduced stability of bilayer Tb:In2O3 TFTs is improved with low threshold voltage shift of 0.26 V and −0.38 V under negative-bias illumination stress (NBIS) and negative-bias temperature illumination stress (NBTIS), respectively
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