27 research outputs found

    Assessing the benefit of satellite-based Solar-Induced Chlorophyll Fluorescence in crop yield prediction

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    Large-scale crop yield prediction is critical for early warning of food insecurity, agricultural supply chain management, and economic market. Satellite-based Solar-Induced Chlorophyll Fluorescence (SIF) products have revealed hot spots of photosynthesis over global croplands, such as in the U.S. Midwest. However, to what extent these satellite-based SIF products can enhance the performance of crop yield prediction when benchmarking against other existing satellite data remains unclear. Here we assessed the benefits of using three satellite-based SIF products in yield prediction for maize and soybean in the U.S. Midwest: gap-filled SIF from Orbiting Carbon Observatory 2 (OCO-2), new SIF retrievals from the TROPOspheric Monitoring Instrument (TROPOMI), and the coarse-resolution SIF retrievals from the Global Ozone Monitoring Experiment-2 (GOME-2). The yield prediction performances of using SIF data were benchmarked with those using satellite-based vegetation indices (VIs), including normalized difference vegetation index (NDVI), enhanced vegetation index (EVI), and near-infrared reflectance of vegetation (NIRv), and land surface temperature (LST). Five machine-learning algorithms were used to build yield prediction models with both remote-sensing-only and climate-remote-sensing-combined variables. We found that high-resolution SIF products from OCO-2 and TROPOMI outperformed coarse-resolution GOME-2 SIF product in crop yield prediction. Using high-resolution SIF products gave the best forward predictions for both maize and soybean yields in 2018, indicating the great potential of using satellite-based high-resolution SIF products for crop yield prediction. However, using currently available high-resolution SIF products did not guarantee consistently better yield prediction performances than using other satellite-based remote sensing variables in all the evaluated cases. The relative performances of using different remote sensing variables in yield prediction depended on crop types (maize or soybean), out-of-sample testing methods (five-fold-cross-validation or forward), and record length of training data. We also found that using NIRv could generally lead to better yield prediction performance than using NDVI, EVI, or LST, and using NIRv could achieve similar or even better yield prediction performance than using OCO-2 or TROPOMI SIF products. We concluded that satellite-based SIF products could be beneficial in crop yield prediction with more high-resolution and good-quality SIF products accumulated in the future

    Epidemiological and genomic analyses of human isolates of Streptococcus suis between 2005 and 2021 in Shenzhen, China

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    Streptococcus suis (S. suis) is an important food-borne zoonotic pathogen that causes swine streptococcosis, which threatens human health and brings economic loss to the swine industry. Three-quarters of human S. suis infections are caused by serotype 2. A retrospective analysis of human S. suis cases in Shenzhen, a megacity in China, with high pork consumption, between 2005 and 2021 was conducted to understand its genomic epidemiology, pathogen virulence, and drug resistance characteristics. The epidemiological investigation showed that human cases of S. suis in Shenzhen were mainly associated with people who had been in close contact with raw pork or other swine products. Whole-genome sequence analysis showed that 33 human isolates in Shenzhen were dominated by serotype 2 (75.76%), followed by serotype 14 (24.24%), and the most prevalent sequence types (STs) were ST7 (48.48%) and ST1 (39.40%). ST242 (9.09%) and ST25 (3.03%), which were rarely reported, were also found. Phylogenetic analysis showed that the Shenzhen human isolates had close genetic relatedness to isolates from Guangxi (China), Sichuan (China), and Vietnam. We found a new 82 KB pathogenicity island (PAI) in the serotype 2 isolate that may play a role in sepsis. Similarly, a serotype 14 isolate, containing 78 KB PAI, was isolated from a patient presenting with streptococcal toxic shock syndrome (STSLS) who subsequently died. Multi-drug resistance (MDR) was high in human isolates of S. suis from Shenzhen. Most human isolates were resistant to tetracycline, streptomycin, erythromycin, and clindamycin, and 13 isolates had intermediate resistance to penicillin. In conclusion, swine importation from Guangxi, Sichuan, and Vietnam should be more closely monitored, and the use of antibiotics limited to reduce the potential for antimicrobial resistance (AMR)

    Catalytic Cleavage of C(sp2)−C(sp2) Bonds with Rh-Carbynoids

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    We report a catalytic strategy that generates rhodium-carbynoids by selective diazo activation of designed carbyne sources. We found that rhodium-carbynoid species provoke C(sp2)–C(sp2) bond scission in alkenes by inserting a monovalent carbon unit between both sp2-hybridized carbons. This skeletal remodeling process accesses synthetically useful allyl cation intermediates that conduct to valuable allylic building blocks upon nucleophile attack. Our results rely on the formation of cyclopropyl-I(III) intermediates able to undergo electrocyclic ring-opening, following the Woodward–Hoffmann–DePuy rules

    A literature review of the factors limiting the application of BIM in the construction industry

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    Building Information Modeling (BIM) has had a profound effect on the construction industry. It has greatly improved coordination among stakeholders, enhanced productivity, and increased profits. However, many factors still limit the application of BIM in the construction industry. This study conducts a literature review to identify these negative factors. Firstly, twenty-two sub-factors are identified and classified into five categories: Technology, Cost, Management, Personnel, and Legal. Secondly, some suggestions for eliminating these limiting factors are given. Finally, the study also identifies further research directions for improving BIM theory and applying BIM technology widely and successfully. The results of this study will provide support for practitioners who are using or plan to use BIM. First published online: 03 Nov 201

    Adverse childhood experiences and depressive symptoms among lesbian and bisexual women in China

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    Abstract Background Despite the relationship between Adverse childhood experiences (ACEs) and depressive symptoms, which has been well researched in general populations, little is known about homosexual and bisexual populations, especially lesbian and bisexual women in China. This study aims to investigate the prevalence of ACEs and depressive symptoms and to analyze the relationship between them among lesbian and bisexual women in China. Methods The eligible participants were aged 16 years or older who report their sexual orientation as homosexual or bisexual. The data was collected through anonymous questionnaires with the help of Lespark in Beijing from July 18 to December 29, 2018, and all participants had informed consent to this study. Univariate analysis and multiple linear regression analyses were performed to explore the relationship between ACEs and depressive symptoms among lesbian and bisexual women. All statistical analyses were conducted by the software of SPSS 22.0. Results Among 301 lesbian and bisexual women, 81.4% were lesbian, 18.4% were bisexual women, and the majority were 21–30 years. As for ACEs, 51.5% reported at least one ACE, in which emotional neglect (22.6%) and emotional abuse (22.3%) were common ACEs. As for depressive symptoms of lesbian and bisexual women, the detection rate was 56.1%. The multiple linear regression analyses showed that abuse (β = 2.95, 95%CI:1.07–4.83) and neglect (β = 3.21, 95%CI:1.09–5.31) were positively associated with depressive symptoms and lesbian and bisexual women with three (β = 4.11, 95%CI: 0.99–7.22) or more (β = 6.02, 95%CI: 3.23–8.78) ACEs suffered from more depressive symptoms than others. Conclusion Adverse childhood experiences (ACEs) and depressive symptoms were at high prevalence among lesbian and bisexual women in China. ACEs were associated with depressive symptoms, especially childhood abuse and neglect experiences that have a significant effect on lesbian and bisexual women mental health

    Pd-Catalyzed Enantioselective Hydroalkoxylation of Alkoxyallenes with Phenol for Construction of Acyclic <i>O</i>,<i>O</i>‑Acetals

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    Palladium-catalyzed asymmetric intermolecular hydroalkoxylation of allenes has been developed by using phenol as a pronucleophile. Acyclic <i>O</i>,<i>O</i>-acetals were obtained in high yields (up to 98%) with good to excellent enantiomeric excesses (up to 94% ee)

    LA-ICP-MS U-Pb geochronology and clumped isotope constraints on the formation and evolution of an ancient dolomite reservoir: The Middle Permian of northwest Sichuan Basin (SW China)

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    Recent advances in laser-ablation inductively coupled-plasma mass spectrometry (LA-ICP-MS) in-situ U-Pb radiometric dating and clumped isotope thermometry (Δ) of carbonate minerals provide potential for refining the fluid flow and diagenetic history of carbonate successions. In this study, the Middle Permian dolomites proximal to the Longmenshan fold and thrust belt in northwest Sichuan Basin, southwest China, were investigated using combined U-Pb geochronology, clumped isotope thermometry, and routine isotopic (δC, δO and Sr/Sr) and elemental geochemistry, in an attempt to reveal the possible relevance of carbonate diagenesis and porosity evolution to the basin-scale tectonic/fluid flow events in the framework of absolute time. Overall, formation and evolution of these dolomites temporally correlated well with major tectonic episodes of the Longmenshan fold and thrust belt. Contrary to the previously-assumed volcanic-related model, U-Pb dating and Δ analyses suggest a mid- to late-Triassic replacive dolomitization event (U-Pb ages of 240 ± 12 Ma to 233.8 ± 6.4 Ma) by a hot (Δ temperatures 88– 104 °C) basinal brine, which was likely driven by thrust-related compression of the Longmenshan fold and thrust belt during the Triassic. Replacive dolomitization was immediately followed by cementation of euhedral dolomites (U-Pb age of 228 ± 10 Ma) and blocky calcites (U-Pb ages of 224.8 ± 1.8 Ma to 213.4 ± 3.3 Ma) precipitated from the basinal brine in the same tectonic regime. Afterwards, there was long-term cessation of diagenesis that was coincident with, and thus may well be attributed to, tectono-thermal quiescence during most of the Mesozoic Era and Paleogene. Finally, saddle dolomite cements yield Miocene ages (U-Pb ages of 16.40 ± 0.74 Ma to 12.3 ± 1.2 Ma) and precipitated in pre-existing vugs, representing a hydrothermal fluid flow event (Δ temperatures up to 170 °C) during the reactivation of thrusting. In addition, similarities in U-Pb ages and geochemical signatures between host rocks (replacive dolomites) and the vug-lining dolomite cements suggest that most porosity in these dolomite reservoirs was inherited from the precursor limestones, which probably experienced meteoric leaching during late Permian uplift. This study highlights that there are geodynamic controls on fluid flow and consequent diagenetic evolution of carbonates in tectonically active sedimentary basins. It illustrates that burial alone in this setting is not a sufficient driver for diagenetic alteration and porosity reduction. The combination of U-Pb radiometric dating, clumped isotope thermometry and routine geochemical analyses is a useful approach in refining the diagenetic and porosity evolution history of ancient carbonate successions
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