60 research outputs found

    Global meta-analysis reveals positive effects of biochar on soil microbial diversity

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    Biochar has gained global attention due to its potential for climate change mitigation and soil quality improvement. Yet, the consequences of biochar additions for soil microbes-the major biotic drivers of soil function-remain unknown across global environmental gradients. We aimed to explore the responses of soil bacterial communities to biochar addition, and further investigate how biochar and soil properties impact these responses. We conducted a global meta-analysis and found that, in general, biochar has a limited impact on the proportion of major bacterial phyla, with only Acidobacteria and Gemmatimonadetes being largely impacted: the relative abundance of Acidobacteria decreased by 14.6%, while that of Gemmatimonadetes increased by 19.8%. Also, the experimental type played a role in shaping the response of microbial community to biochar application. In addition, biochar significantly promoted the diversity of soil bacteria, i.e., genetic richness and diversity. These changes were significantly associated with biochar load, C/N ratio, pyrolysis temperature, biochar pH, as well as soil C/N ratio and pH. We further found that the impacts of biochar on functional diversity, i.e., C substrate richness consumed by soil microbes increased with the biochar load, which might relate to increased genetic richness. Our work suggests that selecting key biochar properties can improve soil quality, microbial function, and climate change mitigation while maintaining the positive impacts of biochar on soil microbial diversity. Further research is needed to link the response of soil microbial composition at the genus level to biochar addition, with microbial functions

    Functional response of the soil microbial community to biochar applications

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    Biochar has the potential to mitigate the impacts of climate change and soil degradation by simultaneously sequestering C in soil and improving soil quality. However, the mechanism of biochar's effect on soil microbial communities remains unclear. Therefore, we conducted a global meta-analysis, where we collected 2,110 paired observations from 107 published papers and used structural equation modeling (SEM) to analyze the effects of biochar on microbial community structure and function. Our result indicated that arbuscular mycorrhizal fungal abundance, microbial biomass C, and functional richness increased with biochar addition regardless of loads, time since application, and experiment types. Results from mixed linear model analysis suggested that soil respiration and actinomycetes (ACT) abundance decreased with biochar application. With the increase of soil pH, the effect of biochar on fungal abundance and C metabolic ability was lessened. Higher biochar pH associated with higher pyrolysis temperatures reduced the abundance of bacteria, fungi, ACT, and soil microbes feeding on miscellaneous C from Biolog Eco-plate experiments. SEM that examined the effect of biochar properties, load, and soil properties on microbial community indicated that fungal abundance was the dominant factor affecting the response of the bacterial abundance to biochar. The response of bacterial abundance to biochar addition was soil dependent, whereas fungi abundance was mostly related to biochar load and pyrolysis temperature. Based on soil conditions, controlling biochar load and production conditions would be a direct way to regulate the effect of biochar application on soil microbial function and increase the capacity to sequester C

    Vector quantiser design using reinforced learning

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    Design of clinical intelligent percutaneous myocardial laser revascularization operating platform software

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    Percutaneous transmyocardial laser revasculariztion (PMLR), a kind of new percutaneous coronary intervention based on transmyocardial laser revascularization (TMLR) is to improve the circulation of ischemia myocardium by laser myocardial revascularization from the cardiac cavity. In our previous research, the characteristic of laser transmission in myocardium including photon reflection, absorption and scattering was introduced. The photon state at the emission, transmission and disappearance stage, the processes of photon weight decay and the change of photon movement step and direction were described and simulated by using Monte Carlo method. All of the above were simulated by MATLAB, and the relationship between different optical property parameters, absorption coefficient, scattering coefficient, anisotropic coefficient, and photon energy density in myocardium was discussed. In this study simulation of photon transport using Monte Carlo operating platform was programmed by C++ language to investigate the influence of increasing photons on the simulation at different optical properties parameters and clinical intelligent PMLR operating platform was established to achieve the optimal number of laser holes, aperture, single hole perfusion, threshold power and corresponding parameters of each hole, which provided a reference for the operation program

    Phase plane analysis of traffic flow based on driver’s expected response model

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    At present, researchers have proposed many traffic flow models and research methods of traffic phenomena, but few of them are analyzed from the perspective of system stability. Therefore, this paper proposes a phase plane analysis method from the perspective of traffic flow stability. This method can describe the nonlinear traffic flow phenomenon on the road from the perspective of system global stability. The nonlinear system of the model is obtained by traveling wave substitution and Taylor expansion, and the equilibrium point of the model is solved by specifying the model parameters. According to the qualitative theory of differential equation, the model is further analyzed to judge the type and stability of equilibrium point. Finally, the simulation diagram is used for numerical verification

    Application and Optimization of Biolog EcoPlates in Functional Diversity Studies of Soil Microbial Communities

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    The biological diversity contributes to many aspects of human well-being and ecosystem function, however, we have known very little about microbial diversity due to the limitations of appropriate methodology underneath it. The development of biotech have brought revolutionary progress in the study of microbial diversity in which Biolog required to pay a lot of attention due to its ability of reflecting the metabolic situation of living microbial communities and have used widely in the study of soil microbial communities. However, there are some controversies during its operation procedure and incubation process, handling large data during the analysis might have also caused trouble in the overall process. The approach based on uses of “absolute used”, “INDIRECT” function in Excel could greatly optimize the data analysis, and the increase of principle components in Principle Component Analysis (PCA) were able to extract more information from original data. Besides, the method that through “Taylor” and “logic” transformation for original data before PCA analysis could achieve data analysis optimization. This paper have presented the applications and optimization of Biolog EcoPlates in studies of functional diversity of microbial communities, presented its inherent biases and prospects, provided some reference for the applications and popularization of Biolog EcoPlates for microbial study and finally, the results imply improving the knowledge of biotech in study of soil microbial functional diversity

    Application and Optimization of Biolog EcoPlates in Functional Diversity Studies of Soil Microbial Communities

    No full text
    The biological diversity contributes to many aspects of human well-being and ecosystem function, however, we have known very little about microbial diversity due to the limitations of appropriate methodology underneath it. The development of biotech have brought revolutionary progress in the study of microbial diversity in which Biolog required to pay a lot of attention due to its ability of reflecting the metabolic situation of living microbial communities and have used widely in the study of soil microbial communities. However, there are some controversies during its operation procedure and incubation process, handling large data during the analysis might have also caused trouble in the overall process. The approach based on uses of “absolute used”, “INDIRECT” function in Excel could greatly optimize the data analysis, and the increase of principle components in Principle Component Analysis (PCA) were able to extract more information from original data. Besides, the method that through “Taylor” and “logic” transformation for original data before PCA analysis could achieve data analysis optimization. This paper have presented the applications and optimization of Biolog EcoPlates in studies of functional diversity of microbial communities, presented its inherent biases and prospects, provided some reference for the applications and popularization of Biolog EcoPlates for microbial study and finally, the results imply improving the knowledge of biotech in study of soil microbial functional diversity

    Properties of a Steel Slag–Permeable Asphalt Mixture and the Reaction of the Steel Slag–Asphalt Interface

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    Steel slag is an industrial solid waste with the largest output in the world. It has the characteristics of wear resistance, good particle shape, large porosity, etc. At the same time, it has good adhesion characteristics with asphalt. If steel slag is used in asphalt pavement, it not only solves the problem of insufficient quality aggregates in asphalt concrete, but can also give full play to the high hardness and high wear resistance of steel slag to improve the performance of asphalt pavement. In this study, a steel slag aggregate was mixed with road petroleum asphalt to prepare a permeable steel slag–asphalt mixture, which was then compared with the permeable limestone–asphalt mixture. According to the Technical Regulations for Permeable Asphalt Pavement (CJJT 190-2012), the permeability, water stability, and Marshall stability of the prepared asphalt mixtures were tested and analyzed. In addition, the high-temperature stability and expansibility were analyzed according to the Experimental Regulations for Highway Engineering Asphalt and Asphalt Mixture (JTG E20-2011). The chemical composition of the steel slag was tested and analyzed by X-ray fluorescence spectrometer (XRF). The mineral composition of the steel slag was tested and analyzed by X-ray diffractometer (XRD). The asphalt was analyzed by Fourier transform infrared spectroscopy (FTIR). The results show that the steel slag asphalt permeable mixture had good permeability, water stability, and Marshall stability, as well as good high-temperature stability and a low expansion rate. The main mineral composition was ferroferric oxide, the RO phase (RO phase is a broad solid solution formed by melting FeO, MgO, and other divalent metal oxides such as MnO), dicalcium silicate, and tricalcium silicate. In the main chemical composition of steel slag, there was no chemical reaction between aluminum oxide, calcium oxide, silicon dioxide, and asphalt, while ferric oxide chemically reacted with asphalt and formed new organosilicon compounds. The main mineral composition of the steel slag (i.e., triiron tetroxide, dicalcium silicate, and tricalcium silicate) reacted chemically with the asphalt and produced new substances. There was no chemical reaction between the RO phase and asphalt

    The Joint Effect of Presentation Format and Disclosure Balance on Investors’ Reactions to Sensitivity Disclosures of Hedging Instruments

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    Inquiries about this document can be made to [email protected] risk disclosure has been a key issue in accounting regulations and research. In this paper, we examine how investors react to two features of the most popular form of mandatory quantitative risk disclosure-sensitivity analysis. Specifically, we experimentally test how the presentation format of market risk impact and disclosure balance (i.e., showing either potential losses only or both potential losses and potential gains) interact to change investors’ reactions to sensitivity disclosures of hedging instruments. We find that investors judge a firm that provides an SEC FRR No. 48-minimum disclosure to be as unfavorable as an otherwise equivalent firm that leaves its risk exposure unhedged. We further find that a presentation format that shows the market risk impact after hedging improves investors’ judgments when the disclosure is onesided loss-only but not when it is two-sided. A mediation analysis shows that the enhanced presentation format alters investors’ judgments by reducing their worry about unfavorable changes in market conditions. We contribute to the literature by showing that the presentation format of sensitivity disclosures matters and by identifying a moderator to the effect of disclosure balance. Our results have important implications for investors, managers, and regulators

    Consolidated Bioprocess for Bioethanol Production from Lignocellulosic Biomass Using Clostridium thermocellum DSM 1237

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    A consolidated bioprocessing (CBP) using Clostridium thermocellum DSM 1237 for bioethanol production in anaerobic bottles and a 3-L fermenter from biomass was investigated. The effects of key operational parameters including different carbon sources, temperature, and substrates on the metabolic performance of the strain were firstly evaluated. It was found that ethanol yield reached 0.60 g/L with a cell biomass of 0.80 g/g at the optimal temperature of 60 degrees C with 0.5% (w/v) cellobiose. Further experiments indicated that sugarcane bagasse (SCB) could be utilized to efficiently culture this strain. Ethanol yield reached 0.68 g/L (65.8% of theoretical yield) from alkali-pretreated SCB. In the subsequent 3-L fermenter trial, the maximum ethanol 0.86 g/L (83.3% of theoretical yield) was achieved, with enzymes enriched in both cellulase and xylanase. The CBP provided enzymes on-site and integrated hydrolysis and fermentation in one-step, which might be an effective approach for economic bioethanol production
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