Evaluating the relative merits of competing models based on empirical likelihood ratio test

<p>Competing models arise naturally in many research fields, such as survival analysis and economics, when the same phenomenon of interest is explained by different researcher using different theories or according to different experiences. The model selection problem is therefore remarkably important because of its great importance to the subsequent inference; Inference under a misspecified or inappropriate model will be risky. Existing model selection tests such as Vuong's tests [<a href="#CIT0026" target="_blank">26</a>] and Shi's non-degenerate tests [<a href="#CIT0021" target="_blank">21</a>] suffer from the variance estimation and the departure of the normality of the likelihood ratios. To circumvent these dilemmas, we propose in this paper an empirical likelihood ratio (ELR) tests for model selection. Following Shi [<a href="#CIT0021" target="_blank">21</a>], a bias correction method is proposed for the ELR tests to enhance its performance. A simulation study and a real-data analysis are provided to illustrate the performance of the proposed ELR tests.</p

Stability of the Halide Double Perovskite Cs₂AgInBr₆

Cs2AgInBr6 is among the lead-free halide perovskites of interest, predicted by first-principles calculations to be stable with a direct band gap, but there has been only one report of its synthesis. Herein we report the formation of Cs2AgInBr6 thin films through thermal evaporation of CsBr, AgBr, and InBr3 and subsequent annealing between 130 °C and 250 °C. Cs2AgInBr6 appears stable in this temperature range. However, Cs2AgInBr6 thin films are thermodynamically unstable at room temperature, remaining cubic only long enough to be characterized but not long enough to be useful for practical devices. Cs2AgInBr6 decomposed into Cs2AgBr3, Cs3In2Br9, AgBr, and InBr3 upon cooling from 130 °C to 250 °C to room temperature. This conclusion did not depend on illumination, film thickness, annealing environment, or details of the film formation, pointing to an intrinsic thermodynamic instability of the material. Optical absorption measurements may be interpreted as Cs2AgInBr6 having a direct band gap of 1.57 ± 0.1 eV

High-Efficiency Simultaneous Oxidation of Organoarsenic and Immobilization of Arsenic in Fenton Enhanced Plasma System

Roxarsone (ROX), an organoarsenic compound serving as a common feeding additive, is heavily utilized in the agricultural field and brings about the potential risks of toxic inorganic arsenic contamination in the ambient environment. In this study, the applicability of glow discharge plasma (GDP) for simultaneous oxidation of organoarsenic and immobilization of arsenic is unprecedentedly evaluated. The results show that ROX can be effectively oxidized to inorganic arsenic, and this performance is evidently dependent on energy input. Adding Fe­(II) can significantly enhance the oxidation of ROX mainly because of the additional production of ^•OH via Fenton reaction in GDP, accompanied by which the generated arsenic can be simultaneously immobilized in one process. The immobilization of arsenic can be favorably obtained at pH 4.0–6.0 and Fe­(II) concentration ranging from 500 to 1000 μM. On the basis of the mineral compositions and analysis (XRD/FTIR/XPS) of precipitate, a mechanism can be proposed that the oxidation of Fe­(II) by H₂O₂ generated in situ in GDP significantly accelerates ROX transformation to the ionic As­(V), which can immediately precipitate with Fe­(III) ions or be adsorbed on the ferric oxyhydroxides, forming amorphous ferric arsenate-bearing ferric oxyhydroxides. As such, the present study offer a new recipe for rapid decontamination of organoarsenic pollutants, in which the hypertoxic species can be effectively removed from the wastewater

Synergetic Transformations of Multiple Pollutants Driven by Cr(VI)–Sulfite Reactions

Reduction of Cr­(VI) is often deemed necessary to detoxify chromium contaminants; however, few investigations utilized this reaction for the purpose of treating other industrial wastewaters. Here a widely used Cr­(VI)–sulfite reaction system was upgraded to simultaneously transform multiple pollutants, namely, the reduction of Cr­(VI) and oxidation of sulfite and other organic/inorganic pollutants in an acidic solution. As­(III) was selected as a probe pollutant to examine the oxidation capacity of a Cr­(VI)–sulfite system. Both ^•OH and SO₄^•– were considered as the primary oxidants for As­(III) oxidation, based on the results of electron spin resonance, fluorescence spectroscopy, and specific radicals quenching. As­(III)-scavenging, oxidative radicals greatly accelerated Cr­(VI) reduction and simultaneously consumed less sulfite. In comparison with a Cr­(VI)–H₂O₂ system with 50 μM Cr­(VI), Cr­(VI), the sulfite system had excellent performance for both As­(III) oxidation and Cr­(VI) reduction at pH 3.5. Moreover, in this escalated process, less sulfite was required to reduce Cr­(VI) than the traditional Cr­(VI) reduction by sulfite process. This effectively improves the environmental compatibility of this Cr­(VI) detoxification process, alleviating the potential for SO₂ release and sulfate ion production in water. Generally, this study provides an excellent example of a “waste control by waste” strategy for the detoxification of multiple industrial pollutants

Intestinal microbiotic composition in zebrafish raised in different conditions.

<p>The pie charts represent the core microbiota of Group M (male) (a), Group F (female) (b), Group BPA (male treated with 2000 μg/L BPA) (c) and Group E2 (male treated with 2000 ng/L E2) (d).</p

Summary of intestinal microbiotic species richness estimators for sample groups.

<p>Summary of intestinal microbiotic species richness estimators for sample groups.</p

Two indices of the host evaluated the vitellogenin and triglyceride content in male zebrafish.

<p>a) The mRNA relative expression of VTG by E2 and BPA in male zebrafish liver. b) The triglyceride content in male zebrafish in muscle. Statistical analysis was carried out using one-way ANOVA. Different lower case letters represent significant differences among treatments (P< 0.05).</p

Overall structural comparison of intestinal microbiota in Groups M, F, BPA and E2.

<p><b>a)</b> Principal component analysis scores plot. b) Clustering analysis of intestinal microbiota. The triangle, rhombus, roundness and square represented samples of Groups M, F, BPA and E2, respectively.</p

Network analysis visualizing the dominant genera in Groups M, F, BPA and E2.

<p>Node sizes correspond to the mean relative abundance of each genus. The proportions of genera shared by different groups are represented by the different colors in the pie charts.</p

A series of 3d–4f heterometallic MOFs: syntheses, structures, optical, and electrochemical properties

<p>A series of heterometallic metal-organic frameworks (MOFs) employing pyridine-2,6-dicarboxylate and 1,10-phenanthroline as ligands have been synthesized hydrothermally. In isostructural compounds <b>1</b>–<b>3</b> [Ln(pydc)₃Cu₂(phen)₄]·I·× H₂O (Ln = La (<b>1</b>), Nd (<b>2</b>), Dy (<b>3</b>); x = 6, 5, 5), the metalloligand [Ln(pydc)₃] assembles with [Cu(phen)₂] units to construct a dodecanuclear cluster via Cu–O bonds and π–π interactions. The clusters are further stacked into three-dimensional supramolecular frameworks with nano-sized cavities. In [La(Hpydc)(pydc)₂Zn(phen)₃]·3H₂O (<b>4</b>), the metalloligand [Ln(Hpydc)(pydc)₂] assembles with [Zn(phen)₃] units to construct a tetranuclear cluster via electrostatic interaction and π–π interaction. This work reveals that the changes of lanthanide metalloligands and the coordination pattern of 3d transition centers would result in significant variation in the final structures. The thermal, optical, and electrochemical properties have been well investigated.</p