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We present some general results implying nonfinite axiomatisability of many additively idempotent semirings with finitely based semigroup reducts. The smallest is a $3$-element commutative example, which we show also has \texttt{NP}-hard membership for its variety. As well as being the only nonfinite axiomatisable ai-semiring on $3$-elements, we are able to show that its nonfinite basis property infects many related semirings, including the natural ai-semiring structure on the semigroup $B_2^1$. We also extend previous group-theory based examples significantly, by showing that any finite additively idempotent semiring with a nonabelian nilpotent subgroup is not finitely axiomatisable for its identities.

We introduce an equivalence relation ρ on matrices over a class of semirings, which is relevant to the Kleene star operator on matrices. We characterize those surjective linear transformations for ...

Objective To explore the evaluation value of N-terminal pro-brain natriuretic peptide (NT-proBNP) and cytokines in predicting severe and therapeutic retinopathy of prematurity (ROP).MethodsPremature infants from January 2020 to January 2022 were enrolled in this single-center retrospective study. General characteristics, seven cytokines within 24 hours and NT-proBNP on the 1st, 3rd, 7th and 14th days after birth were collected. Evaluated these risk factors by using univariate Logistic regression and multivariable logistic regression. Receiver operating characteristic curve analysis was used to evaluate the prediction ability. The outcome measures were the occurrence of any stage ROP, severe ROP and therapeutic ROP.Results528 premature infants were involved, 21.4% premature infants (113/528) were diagnosed with ROP, 35.4% (40/113) were diagnosed with severe ROP, 65% (26/40) received intravitreal anti-vascular endothelial growth factor treatment. After adjusting confounding factors, NT-proBNP at day 7 of life (NT-proBNP7) and IL-6 still remained significantly associated with ROP (P < 0.05). For severe ROP, the cut off values for IL-6 and NT-ProBNP7 were respectively 16.28 pg/mL (AUC = 0.830) and 2553ng/L (AUC = 0.846). The AUC value for combining the two indices was 0.919. For therapeutic ROP, the cut off values for IL-6 and NT-ProBNP7 were respectively 18.08 pg/mL (AUC = 0.845) and 4699ng/L (AUC = 0.829). The AUC value for combining the two indices was 0.915.ConclusionsNT-proBNP 7 and IL-6 can be used as early biomarkers for severe and therapeutic ROP. More importantly, two indicators have significantly higher efficacy than individual indicators.

In order to explore the analysis of educational management strategies in Colleges and universities, a method based on entropy and dissipative structure theory is proposed. Firstly, we determine the connection length B, which refers to the shortest path between two elements in the structure diagram. The length of direct connection is 1, and the length of each transfer is added by 1. Secondly, calculate the total number of microscopic states of the system, A 1, A 1 = ∑ ∑ Lab {A_1} = \sum {\sum {Lab} } . Third, calculate the probability value of the realization of the micro state of each connection: P ( a , b ) = L ab A a P\left( {a,b} \right) = {{L _{ab}} \over {{A_a}}} . Finally, the entropy of organizational structure between any two elements of the system at the same level vertically and horizontally is calculated: H 1(ab) = −Pa (ab) ln Pa (ab). The experimental results show that student satisfaction is considered to be an important dimension of management team performance evaluation. Through the survey of student satisfaction, it is found that the student satisfaction rate of two teams is 100%, the student satisfaction rate of two teams is 99%, and the satisfaction rate of one team is 98.5%, which shows that the management team has good performance. It is proved that the theory of entropy and dissipative structure can effectively improve the educational management strategy of colleges and universities.

We study the ai-semiring variety defined by the identity x n ≈ x. We show that some subvarieties of this variety are determined by certain properties of some binary relations and provide equational basis for them. Also, we provide models of the free objects in some subvarieties of this variety.

We study the lattice $${{\mathscr {L}}}({{\mathbf{CSr}}}(n, 1))$$ of subvarieties of the ai-semiring variety $${{\mathbf{CSr}}}(n, 1)$$ defined by $$x^n\approx x$$ and $$xy\approx yx$$ . We divide $${{\mathscr {L}}}({{\mathbf{CSr}}}(n, 1))$$ into five intervals and provide an explicit description of each member of these intervals except $$[{{\mathbf{CSr}}}(2, 1), {\mathbf{CSr}}(n, 1)]$$ . Based on these results, we show that if $$n-1$$ is square-free, then $${{\mathscr {L}}}({{\mathbf{CSr}}}(n, 1))$$ is a distributive lattice of order $$2+2^{r+1}+3^r$$ , where r denotes the number of prime divisors of $$n-1$$ . Also, all members of $${{\mathscr {L}}}({{\mathbf{CSr}}}(n, 1))$$ are finitely based and finitely generated and so $${{\mathbf{CSr}}}(n, 1)$$ is a Cross variety. Moreover, the axiomatic rank of each member of $${\mathscr {L}}({{\mathbf{CSr}}}(n, 1))$$ is less than four.

In the process of promoting the development of a low-carbon economy, green services lag behind the green manufacturing industry. This paper applies the textual analysis method and systematically analyses the evolutionary trends and structural characteristics of green service policies to further optimise the service policy system and strengthen the quality of the green service supply. This paper identifies 859 policies introduced since 1986 and uses the content analysis method to analyse changes in the number of policies, the relationships between policy subjects, the formal types of texts and the composition of policy instruments. The results show that (1) the number and overall effectiveness of green service industry policies promulgated by the central government are increasing, such that the formulation of green service industry policies has passed the exploratory phase and has entered the stage of high-quality development; (2) there is a wide range of obvious interministerial cooperative phenomena, the modes of cooperation are relatively fixed, and the overall intersuperior cooperation has been strengthened but is characterised by phased development; (3) the distribution of policy forms is uneven, with many documents characterised by low effectiveness and a lack of high-efficiency documents; (4) the policy object structure is relatively complete, but the industrial distribution is unbalanced; (5) there is an imbalance among the three policy tools of supply, environment and demand. Those tools that are embodied in the environment are deemed more important than those of supply and demand.

Background Glutathione S-transferases (GSTs) are a superfamily of multifunctional dimeric proteins existing in both prokaryotic and eukaryotic organisms. They are involved in the detoxification of both endogenous and exogenous electrophiles, including insecticides. However, the molecular mechanisms underlying the regulation of GST genes in insects are poorly understood. Results We first identified at least three GST genes involved in resistance to the insecticides chlorpyrifos and cypermethrin. Analysis of upstream sequences revealed that three GSTs (SeGSTo2, SeGSTe6 and SeGSTd3) harbor the same cap 'n' collar C/muscle aponeurosis fibromatosis (CncC/Maf) binding site, and SeGSTo2 and SeGSTe6 contain the aryl hydrocarbon receptor/aryl hydrocarbon receptor nuclear translocator (AhR/ARNT) binding site. Luciferase reporter assay showed co-transfection of reporter plasmid containing the SeGSTe6 promoter with CncC and/or Maf expressing constructs significantly boosted transcription. Similarly, AhR and/or ARNT expressing constructs also significantly increased the promoter activities. The co-transfection of mutated reporter plasmid with CncC/Maf or AhR/ARNT did not increase transcription activity anymore. Constitutive over-expression of CncC, Maf and AhR was also found in the HZ16 strain, which might be the molecular mechanism for up-regulated expression of multiple detoxification genes conferring resistance to insecticides. Conclusion These results suggest that CncC/Maf and AhR/ARNT coordinately regulate the expression of multiple GST genes involved in insecticide resistance in Spodoptera exigua. © 2019 Society of Chemical Industry.

In this study, daily average PM2.5 forecasting models were developed and applied in the Northern Xinjiang, China, through combining the back propagation artificial neural network (BPANN) and multiple linear regression (MLR) with another BPANN model. The meteorological (daily average precipitation, pressure, relative humidity, temperature, and wind speed, daily maximum wind speed and sunshine hours on the same day) and air pollutant data (daily PM2.5, PM10, SO2, CO, NO2, and O3 concentrations on the previous day) in January and August of each year from 2015 to 2019 were used as candidate inputs. The optimal member and combining models were evaluated through the leave-one-out cross-validation (LOOCV), fivefold cross-validation, and hold-out methods. Twelve member models with optimal or sub-optimal performance were further used to develop the combining models. The performances of the BPANN and MLR member models were different using three data division methods. The models were evaluated more comprehensively through the LOOCV. The performances of the combining models were generally better than the member models. For both member and combining models, the PM2.5 forecasting model performance in August was generally better than in January. The correlation coefficient (R) for the validation set of the optimal combination model was about 0.87 in January and 0.946 in August. These results showed that combining linear and nonlinear models through multiple data division methods would be an effective tool to forecast PM2.5 concentrations.

The evolution of insect resistance to insecticides is frequently associated with overexpression of one or more cytochrome P450 enzyme genes. Although overexpression of CYP450 genes is a well-known mechanism of insecticide resistance, the underlying regulatory mechanisms are poorly understood. Here we uncovered the mechanisms of overexpression of the P450 gene, CYP321A8 in a major pest insect, Spodoptera exigua that is resistant to multiple insecticides. CYP321A8 confers resistance to organophosphate (chlorpyrifos) and pyrethroid (cypermethrin and deltamethrin) insecticides in this insect. Constitutive upregulation of transcription factors CncC/Maf are partially responsible for upregulated expression of CYP321A8 in the resistant strain. Reporter gene assays and site-directed mutagenesis analyses demonstrated that CncC/Maf enhanced the expression of CYP321A8 by binding to specific sites in the promoter. Additional cis-regulatory elements resulting from a mutation in the CYP321A8 promoter in the resistant strain facilitates the binding of the orphan nuclear receptor, Knirps, and enhances the promoter activity. These results demonstrate that two independent mechanisms; overexpression of transcription factors and mutations in the promoter region resulting in a new cis-regulatory element that facilitates binding of the orphan nuclear receptor are involved in overexpression of CYP321A8 in insecticide-resistant S. exigua., Author summary Insect pests developing resistance to insecticides used for their control is a major problem in agriculture. Many pests including the beet armyworm, Spodoptera exigua have developed resistance to insecticides used for their control. Information on the mechanisms of resistance would help in resistance management programs. Overexpression of detoxifying enzymes were associated with insecticide resistance, but their functions and regulatory mechanisms are still unidentified. The expression levels of P450 genes between susceptible and resistant strains of S. exigua were compared and CYP321A8 was identified as the major contributor to resistance to organophosphate and pyrethroid insecticides. Further studies uncovered two independent but synergistic mechanisms; constitutive upregulation of b-Zip transcription factors and mutations in the promoter that facilitates the binding of an orphan nuclear receptor, Knirps contributing to increase in the expression of CYP321A8 and resistance to multiple insecticides in S. exigua.

In this study, daily average PM

Single-crystal magnesium-doped spinel lithium manganate cathode materials are prepared by the hydrothermal method followed by the heat treatment. XRD patterns reveal that Mg2+ions have already diffused into the Li1.088Mn1.912O4 crystal structure and not affect the Fd3m space group. SEM images demonstrate that the magnesium-doped spinel lithium manganates show uniform polyhedral single crystals with 2–4 μm. Electrochemical performance demonstrates that the optimized composition of Li1.088Mg0.070Mn1.842O4 electrode exhibits the best electrochemical properties. It delivers 92.0 mAh g−1 at 8C rates and corresponds to 90.8% capacity retention (vs. 1C), far higher than those of the pristine electrode (70.4 mAh g−1 and 69.2%). In addition, the Li1.088Mg0.070Mn1.842O4 electrode also shows 95.5% capacity retention after 100 cycles at 1C, while the pristine electrode only shows 91.0% capacity retention. The excellent electrochemical performances of Li1.088Mg0.070Mn1.842O4 electrode are ascribed to the suppressed polarization, more stable crystal structure, and better kinetic characteristics.

Accurate annual runoff forecasting is of great significance for water resources management and timely flood control. However, nonlinear and non-stationary runoff series and the complexity of hydrological processes make it difficult. To improve the forecast accuracy, a hybrid model based on two-stage decomposition, the support vector machine (SVM), and the combined method is proposed. Firstly, the original annual runoff is decomposed into a series of components (IMFs) by the ensemble empirical mode decomposition (EEMD). The high frequency components of IMFs are further decomposed into multiple components (VMFs) by the variational mode decomposition (VMD). Then, the SVM is applied to predict all the components. The sum of the forecast VMFs is the forecast of each high frequency IMF and the forecast annual runoff is obtained by summarizing the forecast IMFs. Finally, all the member models are averaged by the simple average method (SAM), which is the combining model. To evaluate the proposed model, the Pingshi Station in the Lechangxia Basin, China is selected. The results show that the two-stage decomposition enormously enhances the forecasting ability. The validation R of the optimal EEMD-VMD-SVM increases by 20%, 11% and 11% compared with the optimal SVM, EEMD-SVM and VMD-SVM, respectively. The validation MSE decreases by 58%, 45% and 47%, respectively. The optimal combined model outperforms the optimal member model because the validation R and MSE increase and decrease by 3% and 28%, respectively. The optimal combined model consists of four member models based on the EEMD-VMD and one member model based on the EEMD. This study highlights that combining machine learning methods based on two-stage decomposition can effectively improve the forecast accuracy of annual runoff.

Toxicological data demonstrate that nanoplastics (NPs) can cause direct adverse health effects. However, a method for quantifying NPs in biological samples is lacking to date. In this study, a diatomite associated coagulation-sedimentation extraction (CSE) protocol was developed to selectively enrich polystyrene nanoplastics (PS-NP) from microplastics (PS-MP) in the digest of animal tissues, which were then analyzed using pyrolysis gas chromatography-mass spectrometry. We demonstrate that 0.02 g of 7-μm diatomite can selectively adsorb 70-nm PS-NP in 5 mL oyster digest. The method works in the range of 0.006-5 μg PS-NP per 0.5 g wet weight tissue, which has been verified via samples of environmentally contaminated oysters and chow diet PS-NP-treated C57BL/6 mice (digestive tract, kidney, and liver tissues). The particle size-dependent colloidization or buoyancy theoretically supported the general CSE procedure. This work will pave the way for assessing human exposure to NPs and associated health risks.

Cytochrome P450 and UDP‐glucosyltransferase (UGT) as phase I and phase II metabolism enzymes, respectively, play vital roles in the breakdown of endobiotics and xenobiotics. Insects can increase the expression of detoxification enzymes to cope with the stress from xenobiotics including insecticides. However, the molecular mechanisms for insecticide detoxification in Spodoptera exigua remain elusive, and the genes conferring insecticide metabolisms in this species are less well reported. In this study, 68 P450 and 32 UGT genes were identified. Phylogenetic analysis showed gene expansions in CYP3 and CYP4 clans of P450 genes and UGT33 family of this pest. P450 and UGT genes exhibited specific tissue expression patterns. Insecticide treatments in fat body cells of S. exigua revealed that the expression levels of P450 and UGT genes were significantly influenced by challenges of abamectin, lambda‐cyhalothrin, chlorantraniliprole, metaflumizone and indoxacarb. Multiple genes for detoxification were affected in expression levels after insecticide exposures. The results demonstrated that lambda‐cyhalothrin, chlorantraniliprole, metaflumizone and indoxacarb induced similar responses in the expression of P450 and UGT genes in fat body cells; eight P450 genes and four UGT genes were co‐up‐regulated significantly, and no or only a few CYP/UGT genes were down‐regulated significantly by these four insecticides. However, abamectin triggered a distinct response for P450 and UGT gene expression; more P450 and UGT genes were down‐regulated by abamectin than by the other four compounds. In conclusion, P450 and UGT genes from S. exigua were identified, and different responses to abamectin suggest a different mechanism for insecticide detoxification.

We study a variety of Burnside ai-semirings satisfying $$x^n\approx x$$ . It is shown that the multiplicative semigroup of each member of such a variety is a regular orthocryptogroup. As an application, a model of the free object in such a variety is given. Also, some subvarieties of such a variety are characterized. Thus some results obtained respectively by Ghosh et al. (Order 22:109–128, 2005) and Pastijn and Zhao (Algebra Universalis 54:301–321, 2005) are generalized and extended.

Monzo characterized semigroups which are semilattices of rectangular bands and groups of exponent 2. Recently, Ara\(\acute{\text {u}}\)jo and Kinyon gave a new characterization for that class of semigroups and in the end of their paper asked a number of questions. In this note we characterize semilattices of rectangular bands and groups, thus generalizing Ara\(\acute{\text {u}}\)jo and Kinyon’s result and providing partial solutions to the questions they ask.

Glutathione S-transferases (GSTs) are a family of multifunctional enzymes that are involved in detoxification of electrophilic toxic compounds. Although the co-induced expression of GST genes by insecticides in insects has been documented in recent years, the underlying regulatory mechanisms are not understood. In this study, a total of thirty-one cytosolic S. exigua GSTs (SeGSTs) was cloned and identified. The bioinformatics and gene expression patterns were also analyzed. Out of them, SeGSTe9, SeGSTs6, SeGSTe1, SeGSTe6, SeGSTe8, SeGSTe14, and SeGSTd1 were significantly co-expressed following exposure to three insecticides (lambda-cyhalothrin, chlorpyrifos and chlorantraniliprole). The analysis of upstream sequences revealed that all of these seven SeGSTs harbored CncC/Maf binding site. The luciferase reporter assay showed that the pGL3-SeGST promoter construct exhibited a significant increase in luciferase activities after exposure to insecticides, and mutation of CncC/Maf binding site diminish the induction effect. These data indicate that CncC/Maf pathway regulates the co-expression of GST genes in response to different insecticides in S. exigua. Insecticides significantly enhanced the ROS content and treatment with the ROS inhibitor N-acetylcysteine (NAC) decreased the insecticide-induced luciferase activities of the PGL3-GSTe6 promoter construct, but not the CncC-mutated construct. These results indicate that ROS mediates GST gene expression after exposure to insecticides through CncC/Maf pathway. Overall, these data show that insecticides induce the co-expression of glutathione S-transferases through the ROS/CncC pathway in S. exigua.

SAR images plays a critical role in observing and understanding buildings in urban areas. Yet traditional image databases come with a high cost. It is therefore highly desirable to develop a novel approach to achieve realistic simulated SAR images. In this paper, a simulation method focused on the geometrical features of buildings is introduced. The intensity of the simulated image is obtained by an improved Phong-Shading model. And a ray tracer software, Pov-Ray, is used to establish the mapping between the 3D scene and the 2D SAR images. Then, post processing is introduced to render the SAR images more realistic. The proposed method is evaluated by assessing the similarity between real images and simulated images. Experimental results demonstrate that the proposed method yields a high similarity in the geometrical structures. Various geometrical targets can be combined together to make a complex object. This modular approach can establish a database with a great number of simulated SAR images.

In this paper we study the semiring variety V generated by any finite number of finite fields F1,..., Fk and two-element distributive lattice B2, i.e., V = HSP{B2, F1,..., Fk}. It is proved that V is hereditarily finitely based, and that, up to isomorphism, the two-element distributive lattice B2 and all subfields of F1,..., Fk are the only subdirectly irreducible semirings in V.

We introduce the notion of a sturdy frame of abstract algebras which is a common generalization of a sturdy semilattice of semigroups, the sum of lattice ordered systems, the strong distributive lattice of semirings, the sturdy frame of type (2, 2) algebras and the strong b-lattice of semirings. Also, we give some properties and characterizations of the sturdy frame of abstract algebras. As an application, we study the sturdy distributive lattice of lattice ordered groups.

Nowadays, Grid technology is a hot research topic. The application of grid technology to knowledge management can maximize the integration of existing resources. With the application of distributed management, the effective management of knowledge can change the current disorder of knowledge resources. Taking the LOM knowledge classification standard as the basis of the division of knowledge grid metadata community and according to the characteristics of grid management architecture, this paper constructs the grid community model based on knowledge resource metadata as the framework of knowledge management. This study discusses the construction of grid community. The internal structure of the community are the communicating system between communities, according to the characteristics of grid community.

We study the variety $$\mathbf {S}_\mathbf{2}$$ generated by all ai-semirings of order two. We prove that the lattice of all subvarieties of $$\mathbf {S}_{ \mathbf 2}$$ is a Boolean algebra of order 64 and provide a finite equational basis for each member of the lattice.

A novel hydrothermal process followed by heat treatment was used for the preparation of the layered LiNi 0.5 Co 0.2 Mn 0.3 O 2 cathode materials for lithium ion batteries. The lithiated metal oxide precursor obtained from the hydrothermal process had a homogeneous distribution of metals and a weak crystallinity. The layered LiNi 0.5 Co 0.2 Mn 0.3 O 2 powders were obtained by the post-heat treatment of the lithiated metal oxide. The materials were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), inductively coupled plasma (ICP), atomic absorption spectroscopy (AAS), cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and galvanostatic charge/discharge testing. The cathode material with hexagonal α-NaFeO 2 structure, low cation mixing, appropriate crystallinity and homogeneous spherical particles was obtained. The results indicated that the initial discharge capacities of the cathode material were 150 mAh g −1 , 165.7 mAh g −1 and 184.8 mAh g −1 at the discharge rate of 0.5 C (100 mA g −1 ) with the cut-off voltage range of 3.0–4.3 V, 2.8–4.4 V and 2.5–4.5 V, respectively, and it retained 97.6%, 99.4% and 99.2% of the initial capacity after 50 cycles. It indicated that the novel hydrothermal lithiation followed by post-heat treatment is a promising route for the synthesis of LiNi 0.5 Co 0.2 Mn 0.3 O 2 cathode material with improved properties.

Li 2 TiO 3 powders were obtained by in-situ hydrolysis route along with water washing process, in which TiCl 4 and LiOH·H 2 O were used as raw materials. The removal of soluble chloride salt in the as-prepared Li 2 TiO 3 samples by water-washing process and the effect of Cl − upon the morphology and the sintering behavior of the Li 2 TiO 3 powders have been studied. The results indicated that more than 90% of Cl − can be easily removed from the heat treated Li 2 TiO 3 powders by water-washing. The samples after water-washing are in cube-like shape with uniform particle size distribution, while the original powders are cohered together with irregular morphology. Compared with the originally unwashed Li 2 TiO 3 powders, the washed samples show better sinterability. The density and thermal shrinkage rate of the sintered Li 2 TiO 3 pellets increase with a decrease of the Cl − content in the sample. Sintered body with the relative density of 90.9% T.D. (theoretical density based on the Li 2 TiO 3 single crystal density of 3.43 g/cm 3 ) and the thermal shrinkage rate of 13.1% was obtained from the water washed Li 2 TiO 3 powders, whereas the T.D. and the thermal shrinkage rate were only 72.7% and 10.3% in the sintered body of unwashed sample, respectively. The results illustrated that Cl − had a significant effect on the properties of the Li 2 TiO 3 samples, including purity, morphology and sintering behavior. The removal of Cl − from the Li 2 TiO 3 samples obtained by in-situ hydrolysis is necessary for producing high-quality Li 2 TiO 3 pellets.