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关键词： glutathione   Nicotiana benthamiana   reactive oxygen species   salicylic acid   systemic resistance   tobacco mosaic virus  

摘要： Systemic acquired resistance (SAR) is induced by pathogens and confers protection against a broad range of pathogens. Several SAR signals have been characterized, but the nature of the other unknown signalling by small metabolites in SAR remains unclear. Glutathione (GSH) has long been implicated in the defence reaction against biotic stress. However, the mechanism that GSH increases plant tolerance against virus infection is not entirely known. Here, a combination of a chemical, virus-induced gene-silencing-based genetics approach, and transgenic technology was undertaken to investigate the role of GSH in plant viral resistance in Nicotiana benthamiana. Tobacco mosaic virus (TMV) infection results in increasing the expression of GSH biosynthesis genes NbECS and NbGS, and GSH content. Silencing of NbECS or NbGS accelerated oxidative damage, increased accumulation of reactive oxygen species (ROS), compromised plant resistance to TMV, and suppressed the salicylic acid (SA)-mediated signalling pathway. Application of GSH or l-2-oxothiazolidine-4-carboxylic acid (a GSH activator) alleviated oxidative damage, decreased accumulation of ROS, elevated plant local and systemic resistance, enhanced the SA-mediated signalling pathway, and increased the expression of ROS scavenging-related genes. However, treatment with buthionine sulfoximine (a GSH inhibitor) accelerated oxidative damage, elevated ROS accumulation, compromised plant systemic resistance, suppressed the SA-mediated signalling pathway, and reduced the expression of ROS-regulating genes. Overexpression of NbECS reduced oxidative damage, decreased accumulation of ROS, increased resistance to TMV, activated the SA-mediated signalling pathway, and increased the expression of the ROS scavenging-related genes. We present molecular evidence suggesting GSH is essential for both local and systemic resistance of N. benthamiana to TMV through a differential modulation of SA and ROS.

关键词： Adult   age structure   evolution   juvenile   mortality   sex ratio  

摘要： The classical view of sex ratio evolution, popularized by R. A. Fisher, is that the sex ratio at birth should be equal when males and females require the same level of parental investment. Thus, although differences in mortality between the sexes during parental investment will cause deviations from an equal sex ratio at birth, differential mortality after parental investment should have no effect. However, a recent theoretical model appears to contradict this view, suggesting that differential mortality after the period of parental investment does cause deviations from an equal sex ratio at birth. Moreover, the life stage at which mortality differs (juvenile vs. adult) is predicted to cause contrasting effects on sex ratio evolution. These results are in stark contrast with Fisher's hypothesis. Here, we resolve this disparity by analyzing a stage- and sex- structured model of population dynamics. We find that selection always drives the population to an equal sex ratio at birth regardless of differential mortality effects after parental investment, thus confirming Fisher's hypothesis. The disparity appears to be due to incorrect accounting of mutant-resident unions, which we avoid by considering separate union classes for different types of mutant-resident unions.

关键词： boundedness   nonlinear oscillation  

摘要： The fourth-order neutral differential equation with damping term is investigated. There are given conditions that are optimal in a certain sense, guaranteeing the oscillation of all proper solutions. The continuability of solutions and the existence of nonoscillatory bounded solutions are investigated as well. Some results are new for equation without delays.

关键词： Topics: Electron impact ionization   Electron scattering   Atomic and molecular collisions   Plasma properties and parameters.  

摘要： In this work, electron impact ionizing collisions on atomic hydrogen embedded in weakly coupled plasmas are studied at impact energies of 80 and 150 eV. Fully differential cross sections calculated by means of a distorted wave model which explicitly considers the screening effect among the three interacting particles in the final state are presented and analyzed. Compared to the unscreened case, clear differences in shape and magnitude are found for the dominant structures, the binary and recoil peaks, suggesting that the role played in the collision by the different particles varies with the Debye screening length. A scaling law for the fully differential cross section in terms of the nuclear charge Z, first proposed by Kornberg and Miraglia in the photo-double ionization context, is shown to also hold for the electron impact ionization of hydrogenic ions in the present screened context.

关键词： Predictor-Corrector method   new generalized Caputo derivative   time delay fractional differential equations   numerical solution  

摘要： In this paper, we modified the Predictor-Corrector scheme to simulate the delay differential equations in new generalised Caputo-type non-classical derivatives sense. We provided some numerical illustrations to exhibit availability of the algorithm. From the graphical simulations, we observed some periodic and chaotic natures of the given systems for different fractional order values. We believe that the presented scheme is expected to be further used to solve delay fractional differential equations in generalized Caputo type fractional-order sense. The original contribution of this research is to provide a generalised numerical algorithm to solve different fractional-order delay-type systems.

关键词： Self adapting differential search strategies   Artificial bee colony algorithm   Cluster head selection   Quality of service (QoS)   Mutation   Crossover  

摘要： The process of cluster head selection under the process of cluster formation in wireless sensor networks is determined to be essential for extending the lifetime of the network. In this paper, a Self Adapting Differential Search Strategies Improved Artificial Bee Colony Algorithm (SADSS-IABCA)-based Cluster Head Selection Scheme is proposed for prolonging the lifetime of the network with improved Quality of Service. The differential search strategies employed in the SADSS-IABCA-based Cluster Head Selection Scheme are reliable in updating the dependent variables in periodic intervals of time through the integration of mutation and crossover. This proposed SADSS-IABCA-based Cluster Head Selection Scheme incorporated diversified search strategies associated with differential evolution with the employee and onlooker bee phase in order to improve the local searching ability of ABC with the view to eliminate its limitations of delayed convergence. In addition, the appropriate selection of differential evolution strategies is computed through the probability-based self adapting process for effective selection of cluster heads. The simulation results of the proposed SADSS-IABCA-based Cluster Head Selection Scheme also confirmed a predominant improvement in percentage of alive nodes, throughput and mean residual energy compared to the benchmarked cluster head schemes used for investigation.

摘要： Background: The heterogeneous composition of substantia nigra (SN), including iron, nigrosome-1 substructure, and myelinated white matter, complicates the interpretation of MRI signals. Purpose: To investigate R2* and quantitative susceptibility mapping (QSM) in the SN subdivisions of participants with Parkinson disease and healthy control subjects. Materials and Methods: In this prospective study conducted from November 2018 to November 2019, participants with Parkinson disease and sex-matched healthy control subjects underwent 3-T MRI. R2(X) and QSM values were measured and compared in the anterior SN and posterior SN at the rostral (superior) and caudal (inferior) levels. Postmortem MRI and histology correlation of midbrain tissues was evaluated to investigate the effect of myelin and iron in the SN on R2* and QSM values. Results: Forty individuals were evaluated: 20 healthy control subjects (mean age, 61 years +/- 3 [standard deviation];10 men) and 20 participants with Parkinson disease (mean age, 61 years +/- 4;10 men). The R2(X) values of participants with Parkinson disease were higher in all subdivisions of the SN compared with R2* values in healthy control subjects (all P,.05). For QSM, no evidence of a difference was found in the rostral posterior SN (healthy control subjects, 54.1 ppb +/- 21.0;Parkinson disease, 62.2 ppb +/- 19.8;P=.49). The combination of rostral R2* and caudal QSM values resulted in an area under the receiver operating characteristic curve of 0.84. R2* values showed higher correlation with QSM values at the caudal level than at the rostral level within each group (all P < .001). Postmortem investigation demonstrated that R2(X) and QSM values showed weak correlation in the myelin-rich areas (r= 0.22 and r = 0.36, P < .001) and strong correlation in myelin-scanty areas (r ranged from approximately 0.52 to approximately 0.78, P < .001) in the SN. Conclusion: Considering the iron and myelin distribution in the substantia nigra subdivisions,

摘要： Differential bundle functioning (DBF) has been proposed to quantify the accumulated amount of differential item functioning (DIF) in an item cluster/bundle (Douglas, Roussos, and Stout). The simultaneous item bias test (SIBTEST, Shealy and Stout) has been used to test for DBF (e.g., Walker, Zhang, and Surber). Research on DBF may have the potential to reveal the mechanism underlying DIF. However, an unresolved issue is the lack of an effect size for DBF, making it difficult to assess and compare the amounts of DBF within and between tests. We propose using meta-analysis techniques to study DBF. By meta-analyzing DIF indices, we can examine the heterogeneity of DIF across items, using the weighted average of DIF indices in an item bundle as a measure of effect size for DBF. A Monte Carlo simulation study compared the performance of our proposed effect size for DBF and a new test of nonzero average DIF in an item bundle with that of a DBF test using SIBTEST. When the primary and secondary dimensions were moderately correlated, our proposed effect size for DBF had little bias;the test of nonzero average DIF also showed power and Type I error levels comparable to those of the DBF test.

关键词： Fractional differential equations   Bihari inequality   fractional integral   fractional derivative   Osgood condition   Kneser's theorem   acyclic set   random solution   stochastic differential equations   Banach lattice   multifunction   upper separated   convex order   Carathedory selection   differential inclusions  

摘要： The purpose of this paper is to present a new version of the Bihari inequality with singular kernel and give a simple proof of the fractional Gronwall lemma. Our new ideas rest on the use of Young's and Holder's inequalities to simplify the complex inequalities. Based on this new type of Bihari inequality we can relax many results of fractional differential equations and inclusions and stochastic differential equations. Also, the obtained inequalities can be used to analyze a specific class of fractional differential equations, both linear and nonlinear. Using the Caputo fractional derivative, the study of an initial valued problem for a fractional differential equation provides some topological proprieties for the solution set, and shows it is the intersection of a decreasing sequence of compact nonempty contractible spaces. We extend the classical Kneser's theorem on the solution structure of the ordinary differential equation and relax some results about the fractional differential equation. Also, we establish existence results for Caputo fractional stochastic differential equations. Finally, we study the existence of solution for fractional differential inclusion in Banach lattice.

关键词： Nonexistence of solutions   fractional differential equation   Hadamard fractional derivative  

摘要： In this paper, we study the nonexistence of nontrivial global solutions for a nonlinear fractional differential. The equation involves two Hadamard fractional derivatives of different orders and a nonlinear source term. Our results are obtained using the test-function method, several properties of fractional derivatives and some integral inequalities. An example is provided to illustrate our findings.