Evaluating the Efficacy of correlation-based Meta-Analytic Structural Equation Modeling Under Different Patterns of Missing Correlations

Missing correlations often happen in the primary correlation matrices and create major problems for the performance of meta-analytic structural equation modeling (MASEM). In current literature, methodological investigation regarding the performance of MASEM methods paired with a large proportion of missing data is limited. This simulation study was designed to investigate the impacts of missing conditions on the correlation-based MASEM performance, utilizing weighted-covariance generalized least squares (W-COV GLS) with pairwise deletion (PD), W-COV GLS with multiple imputation (MI), and two-stage structural equation modeling (TSSEM) to pool the correlation matrices. Specifically, impacts of the study number (k), the within study sample size (n), the proportion of missing correlations (pm), and the proportion of studies reported full matrices (pf) on the performance of MASEM results were explored, with two different factorial models. Conditions where the correlation-based MASEM could produce accurate parameter estimations were identified. The results showed that larger sample size (i.e., k and n) and greater proportion of full matrices (pf) improve model fits, reduce bias in parameter estimates and their standard errors, and decrease the type I error rate. Whereas, the missing proportion (pm) has an inverse function on model fits, parameter and standard error estimates, and type I error rates. W-COV GLS with MI is superior than the other two methods with most missing conditions, but W-COV GLS with PD tends to perform better than W-COV GLS with MI when the missing proportion is extremely small paired with a large proportion of full matrices under the model with unequal factor loadings. Moreover, the outcomes demonstrated the necessity of including at least one study with full correlation matrices in the study pool for TSSEM and W-COV GLS with PD. Suggestions for future research were also described

A comprehensive analysis of Fermi Gamma-Ray Burst Data: IV. Spectral lag and Its Relation to Ep Evolution

The spectral evolution and spectral lag behavior of 92 bright pulses from 84 gamma-ray bursts (GRBs) observed by the Fermi GBM telescope are studied. These pulses can be classified into hard-to-soft pulses (H2S, 64/92), H2S-dominated-tracking pulses (21/92), and other tracking pulses (7/92). We focus on the relationship between spectral evolution and spectral lags of H2S and H2S-dominated-tracking pulses. %in hard-to-soft pulses (H2S, 64/92) and H2S-dominating-tracking (21/92) pulses. The main trend of spectral evolution (lag behavior) is estimated with $\log E_p\propto k_E\log(t+t_0)$ (${\hat{\tau}} \propto k_{\hat{\tau}}\log E$), where $E_p$ is the peak photon energy in the radiation spectrum, $t+t_0$ is the observer time relative to the beginning of pulse $-t_0$, and ${\hat{\tau}}$ is the spectral lag of photons with energy $E$ with respect to the energy band $8$-$25$ keV. For H2S and H2S-dominated-tracking pulses, a weak correlation between $k_{{\hat{\tau}}}/W$ and $k_E$ is found, where $W$ is the pulse width. We also study the spectral lag behavior with peak time $t_{\rm p_E}$ of pulses for 30 well-shaped pulses and estimate the main trend of the spectral lag behavior with $\log t_{\rm p_E}\propto k_{t_p}\log E$. It is found that $k_{t_p}$ is correlated with $k_E$. We perform simulations under a phenomenological model of spectral evolution, and find that these correlations are reproduced. We then conclude that spectral lags are closely related to spectral evolution within the pulse. The most natural explanation of these observations is that the emission is from the electrons in the same fluid unit at an emission site moving away from the central engine, as expected in the models invoking magnetic dissipation in a moderately-high-$\sigma$ outflow.Comment: 58 pages, 11 figures, 3 tables. ApJ in pres

Overexpression of BplERD15 enhances drought tolerance in Betula platyphylla Suk

In this study, we report the cloning and functional characterization of an early responsive gene, BplERD15, from Betula platyphylla Suk to dehydration. BplERD15 is located in the same branch as Morus indica Linnaeus ERD15 and Arabidopsis Heynh ERD15 in the phylogenetic tree built with ERD family protein sequences. The tissue-specific expression patterns of BplERD15 were characterized using qRT-PCR and the results showed that the transcript levels of BplERD15 in six tissues were ranked from the highest to the lowest levels as the following: mature leaves (ML) \u3e young leaves (YL) \u3e roots (R) \u3ebuds (B) \u3eyoung stems (YS) \u3emature stems (MS). Multiple drought experiments were simulated by adding various osmotica including polyethylene glycol, mannitol, and NaCl to the growth media to decrease their water potentials, and the results showed that the expression of BplERD15 could be induced to 12, 9, and 10 folds, respectively, within a 48 h period. However, the expression level of BplERD15 was inhibited by the plant hormone abscisic acid in the early response and then restored to the level of control. The BplERD15 overexpression (OE) transgenic birch lines were developed and they did not exhibit any phenotypic anomalies and growth deficiency under normal condition. Under drought condition, BplERD15-OE1, 3, and 4 all displayed some drought tolerant characteristics and survived from the drought while the wild type (WT) plants withered and then died. Analysis showed that all BplERD15-OE lines had significant lower electrolyte leakage levels as compared to WT. Our study suggests that BplERD15 is a drought-responsive gene that can reduce mortality under stress condition

Cloning, Identification, and Characterization of the rpoS-Like Sigma Factor rpoX from Vibrio alginolyticus

Vibrio alginolyticus ZJ-51 displays phase variation between opaque/rugose colonies (Op) and translucent/smooth colonies (Tr). These colony variants show great differences in biofilm formation and motility. In this study, a gene encoding for an rpoS-like sigma factor, rpoX, has been cloned and characterized. The absence of rpoX did not affect colony switching rate but did decrease biofilm formation in both the Op and the Tr variants. When challenged with hydrogen peroxide, the ΔrpoX in the Op background showed a slightly higher survival rate compared with the wild type, whereas survival was decreased in the Tr background. Deletion of rpoX in the Tr background resulted in a higher ability to resist ethanol challenges and to survive hyperosmolarity challenges, and in the Op background the opposite phenotype was observed. This indicates that the rpoX gene is involved in biofilm formation and stress response but the effects are controlled by colony phase variation in V. alginolyticus

Rutin has anti-asthmatic effects in an ovalbumin-induced asthmatic mouse model

Purpose: To investigate the anti-asthmatic effects of the flavonoid rutin in an ovalbumin (OVA)-induced asthmatic mouse model.Methods: Asthma was induced by OVA induction. Effects of rutin (25–100 mg/kg BW) on interleukins (IL)-4, IL-5, and IL-13 and interferon (IFN)-γ in bronchoalveolar lavage fluid (BALF) and serum OVAspecific IgE levels were assessed by enzyme linked immunosorbent assay (ELISA). Airway hyperresponsiveness (AHR) was measured by determining lung compliance and airway resistance. Expression levels of p-I-κBα, p-NF-κB p65, TNF-α, and Foxp3 were also assessed. The CD4+ CD25+ Foxp3+ T regulatory cell population was determined by flow cytometry.Results: Rutin significantly (p < 0.05) decreased Th2 cytokines (IL-4, IL-5, IL-13), whereas it enhanced IFN-γ levels in BALF. Decreased OVA-specific serum IgE was also observed with improved lung histology. Rutin was effective in reducing AHR and regulating the expression levels of p-I-κBα, p-NF-κB p65, and TNF α, and also increased the CD4+ CD25+ Foxp3+ Treg cell population and Foxp3 mRNA and protein levels.Conclusion: Rutin effectively suppresses OVA-induced asthma and improves airway function by suppressing inflammatory mediators and inflammatory cell infiltration.Keywords: Asthma, CD4+ CD25+, Cytokines, Inflammation, Ovalbumin, Rutin, Protein level

Environmental stress level evaluation approach based on physical model and interval grey association degree

AbstractAssociating environmental stresses (ESs) with built-in test (BIT) output is an important means to help diagnose intermittent faults (IFs). Aiming at low efficiency in association of traditional time stress measurement device (TSMD), an association model is built. Thereafter, a novel approach is given to evaluate the integrated environmental stress (IES) level. Firstly, the selection principle and approach of main environmental stresses (MESs) and key characteristic parameters (KCPs) are presented based on fault mode, mechanism, and ESs analysis (FMMEA). Secondly, reference stress events (RSEs) are constructed by dividing IES into three stress levels according to its impact on faults; and then the association model between integrated environmental stress event (IESE) and BIT output is built. Thirdly, an interval grey association approach to evaluate IES level is proposed due to the interval number of IES value. Consequently, the association output can be obtained as well. Finally, a case study is presented to demonstrate the proposed approach. Results show the proposed model and approach are effective and feasible. This approach can be used to guide ESs measure, record, and association. It is well suited for on-line assistant diagnosis of faults, especially IFs