80 research outputs found
Biosorption of azo dyes by raspberry-like Fe3O4@yeast magnetic microspheres and their efficient regeneration using heterogeneous Fenton-like catalytic processes over an up-flow packed reactor
Raspberry-like Fe3O4@yeast composite microspheres, whose properties integrate the biosorption features of yeast cells with the excellent magnetic and catalytic properties of Fe3O4 nanoparticles were synthesized by a simple electrostatic-interaction-driven self-assembly heterocoagulation. They were successfully applied in an up-flow packed column for the removal of the model water contaminant methylene blue dye (MB) by consecutive bioadsorption-heterogeneous Fenton oxidation cycles. The as-synthesized Fe3O4@yeast composites were characterized by field emission scanning electron microscopy (FE-SEM), energy-dispersive spectroscopy (EDS), powder X-ray diffraction (XRD) and Fourier transform infrared (FT-IR) spectroscopy. The adsorption process was controlled by the electrostatic interactions between the adsorbent and contaminant. The adsorbent is suitable for the adsorption of positively charged compounds at mildly acidic pH, neutral and alkaline pH, with the highest performance observed at alkaline pH. The experimental breakthrough curves measured at different influent MB concentration, flow rate, bed height and pH were modeled by the Yoon-Nelson model. The in-situ regeneration of the contaminant-loaded Fe3O4@yeast microspheres and their reuse in multiple cycles was demonstrated by triggering the heterogeneous Fenton-like reaction catalyzed by the supported magnetite. The raspberry-like Fe3O4@yeast magnetic microsphere should be a promising and practical adsorbent for removal and destruction of positively charged organic compounds in wastewater
Characterization of dust aerosols from ALADIN and CALIOP measurements
Abstract. Atmospheric aerosols have pronounced effects on climate at both regional and global scales, but the magnitude of these effects is subject to considerable uncertainties. A major contributor to these uncertainties is an incomplete understanding of the vertical structure of aerosol, largely due to observational limitations. Spaceborne lidars can directly observe the vertical distribution of aerosols globally and are increasingly used in atmospheric aerosol remote sensing. As the first spaceborne high-spectral-resolution lidar (HSRL), the Atmospheric LAser Doppler INstrument (ALADIN) on board the Aeolus satellite was operational from 2018 to 2023. ALADIN data can be used to estimate aerosol extinction and co-polar backscatter coefficients separately without an assumption of the lidar ratio. This study assesses the performance of ALADIN's aerosol retrieval capabilities by comparing them with Cloud-Aerosol LIdar with Orthogonal Polarization (CALIOP) measurements. A statistical analysis of retrievals from both instruments during the June 2020 Saharan dust event indicates consistency between the observed backscatter and extinction coefficients. During this extreme dust event, CALIOP-derived aerosol optical depth (AOD) exhibited large discrepancies with Moderate Resolution Imaging Spectroradiometer (MODIS) Aqua measurements. Using collocated ALADIN observations to revise the dust lidar ratio to 63.5 sr, AODs retrieved from CALIOP are increased by 46 %, improving the comparison with MODIS data. The combination of measurements from ALADIN and CALIOP can enhance the tracking of aerosols' vertical transport. This study demonstrates the potential for spaceborne HSRL to retrieve aerosol optical properties. It highlights the benefits of spaceborne HSRL in directly obtaining the lidar ratio, significantly reducing uncertainties in extinction retrievals.</p
Proper Inference for Value Function in High-Dimensional Q-Learning for Dynamic Treatment Regimes
<p>Dynamic treatment regimes are a set of decision rules and each treatment decision is tailored over time according to patients’ responses to previous treatments as well as covariate history. There is a growing interest in development of correct statistical inference for optimal dynamic treatment regimes to handle the challenges of nonregularity problems in the presence of nonrespondents who have zero-treatment effects, especially when the dimension of the tailoring variables is high. In this article, we propose a high-dimensional Q-learning (HQ-learning) to facilitate the inference of optimal values and parameters. The proposed method allows us to simultaneously estimate the optimal dynamic treatment regimes and select the important variables that truly contribute to the individual reward. At the same time, hard thresholding is introduced in the method to eliminate the effects of the nonrespondents. The asymptotic properties for the parameter estimators as well as the estimated optimal value function are then established by adjusting the bias due to thresholding. Both simulation studies and real data analysis demonstrate satisfactory performance for obtaining the proper inference for the value function for the optimal dynamic treatment regimes. Supplementary materials for this article are available online.</p
Methodology of mixed load customized bus lines and adjustment based on time windows
<div><p>Custom bus routes need to be optimized to meet the needs of a customized bus for personalized trips of different passengers. This paper introduced a customized bus routing problem in which trips for each depot are given, and each bus stop has a fixed time window within which trips should be completed. Treating a trip as a virtual stop was the first consideration in solving the school bus routing problem (SBRP). Then, the mixed load custom bus routing model was established with a time window that satisfies its requirement and the result were solved by Cplex software. Finally, a simple network diagram with three depots, four pickup stops, and five delivery stops was structured to verify the correctness of the model, and based on the actual example, the result is that all the buses ran 124.42 kilometers, the sum of kilometers was 10.35 kilometers less than before. The paths and departure times of the different busses that were provided by the model were evaluated to meet the needs of the given conditions, thus providing valuable information for actual work.</p></div
Quantile-Optimal Treatment Regimes
<p>Finding the optimal treatment regime (or a series of sequential treatment regimes) based on individual characteristics has important applications in areas such as precision medicine, government policies, and active labor market interventions. In the current literature, the optimal treatment regime is usually defined as the one that maximizes the average benefit in the potential population. This article studies a general framework for estimating the quantile-optimal treatment regime, which is of importance in many real-world applications. Given a collection of treatment regimes, we consider robust estimation of the quantile-optimal treatment regime, which does not require the analyst to specify an outcome regression model. We propose an alternative formulation of the estimator as a solution of an optimization problem with an estimated nuisance parameter. This novel representation allows us to investigate the asymptotic theory of the estimated optimal treatment regime using empirical process techniques. We derive theory involving a nonstandard convergence rate and a nonnormal limiting distribution. The same nonstandard convergence rate would also occur if the mean optimality criterion is applied, but this has not been studied. Thus, our results fill an important theoretical gap for a general class of policy search methods in the literature. The article investigates both static and dynamic treatment regimes. In addition, doubly robust estimation and alternative optimality criterion such as that based on Gini’s mean difference or weighted quantiles are investigated. Numerical simulations demonstrate the performance of the proposed estimator. A data example from a trial in HIV+ patients is used to illustrate the application. Supplementary materials for this article are available online.</p
Image_1_Impact of wine-grape continuous cropping on soil enzyme activity and the composition and function of the soil microbial community in arid areas.pdf
IntroductionContinuous cropping affected the stability of soil enzyme activity and the structural characteristics of microbial community. Owing to challenges in the study of complex rhizosphere microbial communities, the composition and function of these microbial communities in farmland ecosystems remain elusive. Here, we studied the microbial communities of the rhizosphere of wine grapes with different years of continuous cropping and investigated their relationships with soil enzyme activity.MethodsMetagenomic sequencing was conducted on the rhizosphere soils from one uncultivated wasteland and four vineyards with varying durations of continuous cropping.ResultsThe predominant microbial were bacteria (98.39%), followed by archaea (1.15%) and eukaryotes (0.45%). Continuous cropping caused a significant increase in the relative abundance of Rhizobiales and Micrococcales but a marked decrease in Solirubrobacterales. At the genus level, 75, 88, 65, 132, and 128 microbial genera were unique to uncultivated wasteland, 5, 10, 15, and 20 years of continuous cropping, respectively. The relative abundance of genes with signal transduction function was the highest. The activity of all enzymes measured in this study peaked at 5 years of continuous cropping, and then decreased with 10 to 15 year of continuous cropping, but increased at 20 years again. In addition, soil enzyme activity, especially of alkaline phosphatase was significantly correlated with the diversity of the dominant microorganisms at the genus level. Moreover, the coupled enzyme activities had a greater impact on the diversity of the microbial community than that of individual enzymes.ConclusionOur findings reveal the composition and function of the soil microbial communities and enzymes activity in response to changes in cropping years, which has important implications for overcoming continuous cropping obstacles and optimizing land use.</p
Table_1_Impact of wine-grape continuous cropping on soil enzyme activity and the composition and function of the soil microbial community in arid areas.XLSX
IntroductionContinuous cropping affected the stability of soil enzyme activity and the structural characteristics of microbial community. Owing to challenges in the study of complex rhizosphere microbial communities, the composition and function of these microbial communities in farmland ecosystems remain elusive. Here, we studied the microbial communities of the rhizosphere of wine grapes with different years of continuous cropping and investigated their relationships with soil enzyme activity.MethodsMetagenomic sequencing was conducted on the rhizosphere soils from one uncultivated wasteland and four vineyards with varying durations of continuous cropping.ResultsThe predominant microbial were bacteria (98.39%), followed by archaea (1.15%) and eukaryotes (0.45%). Continuous cropping caused a significant increase in the relative abundance of Rhizobiales and Micrococcales but a marked decrease in Solirubrobacterales. At the genus level, 75, 88, 65, 132, and 128 microbial genera were unique to uncultivated wasteland, 5, 10, 15, and 20 years of continuous cropping, respectively. The relative abundance of genes with signal transduction function was the highest. The activity of all enzymes measured in this study peaked at 5 years of continuous cropping, and then decreased with 10 to 15 year of continuous cropping, but increased at 20 years again. In addition, soil enzyme activity, especially of alkaline phosphatase was significantly correlated with the diversity of the dominant microorganisms at the genus level. Moreover, the coupled enzyme activities had a greater impact on the diversity of the microbial community than that of individual enzymes.ConclusionOur findings reveal the composition and function of the soil microbial communities and enzymes activity in response to changes in cropping years, which has important implications for overcoming continuous cropping obstacles and optimizing land use.</p
Modulating Accidental Fermi Resonance: What a Difference a Neutron Makes
Vibrational reporters have shown significant promise as sensitive probes of local environments in proteins and nucleic acids. The utility of two potential vibrational probes, the cyanate and azide groups in phenyl cyanate and 3-azidopyridine, respectively, has been hindered by accidental Fermi resonance. Anharmonic coupling, between the fundamental −OCN or −N<sub>3</sub> asymmetric stretch vibration and a near resonant combination band, results in an extremely broad and complex absorption profile for each of these probes. A total of eight phenyl cyanate and six 3-azidopyridine isotopomers were synthesized and studied. Isotopic editing effectively modulated the accidental Fermi resonance; the absorption profiles of several isotopomers were greatly simplified, whereas others remained complex. The origins of the observed profiles are discussed. The addition of a single neutron to the middle atom of the oscillator converted the absorption profile to essentially a single band, resulting from either the cyanate or azide asymmetric stretch vibration
Images of lentil seeds with normal brown (<i>Ggc Tgc Tan</i>), zero-tannin gray (<i>Ggc tan</i>), and zero-tannin transparent (<i>ggc tan</i>) lentil seed coats.
<p>Images of lentil seeds with normal brown (<i>Ggc Tgc Tan</i>), zero-tannin gray (<i>Ggc tan</i>), and zero-tannin transparent (<i>ggc tan</i>) lentil seed coats.</p
Structure of <i>LcubHLH</i> highlighting the region of the variant related to <i>tan</i>.
<p>The <i>tan</i> lines (Cedar, Shasta and CDC Gold) all have a deletion relative to the <i>Tan</i> lines (964a-46, CDC Redberry, and CDC Robin). The gene structure and the sequence alignment were obtained by FancyGene [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0164624#pone.0164624.ref028" target="_blank">28</a>] tool and BioEdit [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0164624#pone.0164624.ref029" target="_blank">29</a>] alignment software, respectively.</p
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