Controllability of Nonlinear Neutral Evolution Equations with Nonlocal Conditions

In this paper, we establish sufficient conditions for the controllability of nonlinear neutral evolution equations with nonlocal conditions. The result is obtained by using Krasnoselski-Schaefer type fixed point theorem.

Existence and Controllability Result for Nonlinear Neutral Evolution Integrodifferential Systems

In this paper, we establish sufficient conditions for existence and controllability of nonlinear neutral evolution integroditferential systems in Banach spaces. The result is obtained by using the resolvent operators and fixed point analysis approach.

EXISTENCE RESULTS FOR IMPULSIVE NEUTRAL EVOLUTION DIFFERENTIAL EQUATIONS WITH STATE-DEPENDENT DELAY

This paper is mainly concerned with the existence of mild solutions to a first order impulsive neutral evolution differential equations with state-dependent delay. By suitable fixed point theorems combined with theories of evolution systems,we prove some existence theorems. As an application,an example is also given to illustrate the obtained results.

Existence and uniqueness of S-asymptotically periodic α-mild solutions for neutral fractional delayed evolution equation

In this paper, we investigate a class of abstract neutral fractional delayed evolution equation in the fractional power space. With the aid of the analytic semigroup theories and some fixed point theorems, we establish the existence and uniqueness of the S-asymptotically periodic α-mild solutions. The linear part generates a compact and exponentially stable analytic semigroup and the nonlinear parts satisfy some conditions with respect to the fractional power norm of the linear part, which greatly improve and generalize the relevant results of existing literatures.

Preliminary analysis of the mitochondrial genome evolutionary pattern in primates

Since the birth of molecular evolutionary analysis,primates have been a central focus of study and mitochondrial DNA is well suited to these endeavors because of its unique features.Surprisingly,to date no comprehensive evaluation of the nucleotide substitution patterns has been conducted on the mitochondrial genome of primates.Here,we analyzed the evolutionary patterns and evaluated selection and recombination in the mitochondrial genomes of 44 Primates species downloaded from GenBank.The results revealed that a strong rate heterogeneity occurred among sites and genes in all comparisons.Likewise,an obvious decline in primate nucleotide diversity was noted in the subunit rRNAs and tRNAs as compared to the protein-coding genes.Within 13 protein-coding genes,the pattern of nonsynonymous divergence was similar to that of overall nucleotide divergence,while synonymous changes differed only for individual genes,indicating that the rate heterogeneity may result from the rate of change at nonsynonymous sites.Codon usage analysis revealed that there was intermediate codon usage bias in primate protein-coding genes,and supported the idea that GC mutation pressure might determine codon usage and that positive selection is not the driving force for the codon usage bias.Neutrality tests using site-specific positive selection from a Bayesian framework indicated no sites were under positive selection for any gene,consistent with near neutrality.Recombination tests based on the pairwise homoplasy test statistic supported complete linkage even for much older divergent primate species.Thus,with the exception of rate heterogeneity among mitochondrial genes,evaluating the validity assumed complete linkage and selective neutrality in primates prior to phylogenetic or phylogeographic analysis seems unnecessary.

分子水平的非随机进化——相互作用蛋白质间的达尔文选择

通过分析13种生物120余种蛋白质的分子进化,首次揭示:配基-受体、蛋白酶-酶抑制剂、亚基-亚基等相互作用蛋白质间在纵向进化(物种间)、横向进化(不同功能蛋白质间)中均存在协同进化的规律.此结果表明,相互作用蛋白质其分子进化普遍为非随机过程,由于其相互作用为功能发挥所必需,因而彼此间以典型的达尔文选择方式进化.本文结果既弥补了中性理论中分子进化与功能方式无关的不足,亦指出达尔文选择适用于分子进化。

Motivating Ru-bri site of RuO_(2)by boron doping toward high performance acidic and neutral oxygen evolution

The electrocatalysis of oxygen evolution reaction(OER)plays a key role in clean energy storage and transfer.Nonetheless,the sluggish kinetics and poor durability under acidic and neutral conditions severely hinder practical applications such as electrolyzer compatible with the powerful proton exchange membrane and biohybrid fuel production.Here,we report a borondoped ruthenium dioxide electrocatalyst(B-RuO_(2))fabricated by a facile boric acid assisted strategy which demonstrates excellent acidic and neutral OER performances.Density functional theory calculations and advanced characterizations reveal that the boron species form an anomalous B–O covalent bonding with the oxygen atoms of RuO_(2)and expose the fully coordinately bridge ruthenium site(Ru-bri site),which seems like a switch that turns on the inactive Ru-bri site into OER-active,resulting in more exposed active sites,modified electronic structure,and optimized binding energy of intermediates.Thus,the B-RuO_(2)exhibits an ultralow overpotential of 200 mV at 10 mA/cm^(2)and maintains excellent stability compared to commercial RuO_(2)in 0.5 M sulfuric acid.Moreover,the superior performance is as well displayed in neutral electrolyte,surpassing most previously reported catalysts.

Integrated HI emission in galaxy groups and clusters

The integrated HI emission from hierarchical structures such as groups and clusters of galax- ies can be detected by FAST at intermediate redshifts. Here we propose to use FAST to study the evolution of the global HI content of clusters and groups over cosmic time by measuring their integrated HI emissions. We use the Virgo Cluster as an example to estimate the detection limit of FAST, and have estimated the integration time to detect a Virgo type cluster at different redshifts （from z = 0.1 to z ---- 1.5）. We have also employed a semi-analytic model （SAM） to simulate the evolution of HI contents in galaxy clusters. Our simulations suggest that the HI mass of a Virgo-like cluster could be 2-3 times higher and the physical size could be more than 50% smaller when redshift increases from z = 0.3 to z = 1. Thus the integration time could be reduced significantly and gas rich clusters at intermediate redshifts can be detected by FAST in less than 2 hours of integration time. For the local Universe, we have also used SAM simulations to create mock catalogs of clusters to predict the outcomes from FAST all sky surveys. Comparing with the optically selected catalogs derived by cross matching the galaxy catalogs from the SDSS survey and the ALFALFA survey, we find that the HI mass distribution of the mock catalog with 20 s of integration time agrees well with that of observations. However, the mock catalog with 120 s of integration time predicts many more groups and clusters that contain a population of low mass HI galaxies not detected by the ALFALFA survey. A future deep HI blind sky survey with FAST would be able to test such prediction and set constraints on the numerical simulation models. The observational strategy and sample selections for future FAST observations of galaxy clusters at high redshifts are also discussed.

Spontaneous mutations and mutational responses to penicillin treatment in the bacterial pathogen Streptococcus pneumoniae D39

Bacteria with functional DNA repair systems are expected to have low mutation rates due to strong natural selection for genomic stability.However,our study of the wild-type Streptococcus pneumoniae D39,a pathogen responsible for many common diseases,revealed a high spontaneous mutation rate of 0.02 per genome per cell division in mutation-accumulation(MA)lines.This rate is orders of magnitude higher than that of other non-mutator bacteria and is characterized by a high mutation bias in the A/T direction.The high mutation rate may have resulted from a reduction in the overall efficiency of selection,conferred by the tiny effective population size in nature.In line with this,S.pneumoniae D39 also exhibited the lowest DNA mismatch-repair(MMR)efficiency among bacteria.Treatment with the antibiotic penicillin did not elevate the mutation rate,as penicillin did not induce DNA damage and S.pneumoniae lacks a stress response pathway.Our findings suggested that the MA results are applicable to within-host scenarios and provide insights into pathogen evolution.

Random Penetrance of Mutations Among Individuals:A New Type of Genetic Drift in Molecular Evolution

The determinative view of mutation penetrance is a fundamental assumption for the building of molecular evolutionary theory:individuals in the population with the same genotype have the same fitness effect.Since this view has been constantly challenged by experimental evidence,it is desirable to examine to what extent violation of this view could affect our under-standing of molecular evolution.To this end,the author formulated a new theory of molecular evolution under a random model of penetrance:for any individual with the same mutational genotype,the coefficient of selection is a random variable.It follows that,in addition to the conventional Ne-genetic drift(Ne is the effective population size),the variance of penetrance among individuals(ε^(2))represents a new type of genetic drift,coined by theε^(2)-genetic drift.It has been demonstrated that these two genetic drifts together provided new insights on the nearly neutral evolution:the evolutionary rate is inversely related to the log-of-Ne when theε^(2)-genetic drift is nontrivial.This log-of-Ne feature ofε^(2)-genetic drift did explain well why the dN/dS ratio(the nonsynonymous rate to the synonymous rate)in humans is only as twofold as that in mice,while the effective population size(Ne)of mice is about two-magnitude larger than that of humans.It was estimated that,for the first time,the variance of random penetrance in mammalian genes was approximatelyε^(2)≈5.89×10^(-3).

The insect-killing bacterium Photorhabdus luminescens has the lowest mutation rate among bacteria

Mutation is a primary source of genetic variation that is used to power evolution.Many studies,however,have shown that most mutations are deleterious and,as a result,extremely low mutation rates might be benefcial for survival.Using a mutation accumulation experiment,an unbiased method for mutation study,we found an extremely low base-substitution mutation rate of 5.94×10^(-11) per nucleotide site per cell division(95%Poisson confdence intervals:4.65×10^(-11),7.48×10^(-11))and indel mutation rate of 8.25×10^(-12) per site per cell division(95%confdence intervals:3.96×10^(-12),1.52×10^(-11))in the bacterium Photorhabdus luminescens ATCC29999.The mutations are strongly A/T-biased with a mutation bias of 10.28 in the A/T direction.It has been hypothesized that the ability for selection to lower mutation rates is inversely proportional to the efective population size(drift-barrier hypothesis)and we found that the efective population size of this bacterium is signifcantly greater than most other bacteria.This fnding further decreases the lower-bounds of bacterial mutation rates and provides evidence that extreme levels of replication fdelity can evolve within organisms that maintain large efective population sizes.