Unified parametric approaches for high-order integral observer design for matrix second-order linear systems

A type of high-order integral observers for matrix second-order linear systems is proposed on the basis of generalized eigenstructure assignment via unified parametric approaches. Through establishing two general parametric solutions to this type of generalized matrix second-order Sylvester matrix equations, two unified complete parametric methods for the proposed observer design problem are presented. Both methods give simple complete parametric expressions for the observer gain matrices. The first one mainly depends on a series of singular value decompositions, and is thus numerically simple and reliable; the second one utilizes the fight factorization of the system, and allows eigenvalues of the error system to be set undetermined and sought via certain optimization procedures. A spring-mass-dashpot system is utilized to illustrate the design procedure and show the effect of the proposed approach.

Effects of herbicide butachlor application on the growth of periphytic biofilms and nitrogen loss in paddy systems

The application of butachlor as an herbicide in paddy fields is widely practiced,aiming to increase rice yield by directly or indirectly influencing the paddy environment.Periphytic biofilms,which form at the soil-water interface in paddy fields,are complex bioaggregates that play an important role in nitrogen (N) cycling.The objective of this study was to investigate the effect of butachlor on periphytic biofilm growth and N cycling under both light and dark conditions in the laboratory.The results revealed that butachlor application hindered the growth of periphytic biofilms and led to the dominance of Cyanobacteria as the primary prokaryotes,while inhibiting the development of eukaryotic Trebouxiophyceae.Furthermore,the application of butachlor reduced the richness and diversity of prokaryotes,but increased those of eukaryotes in periphytic biofilms.The light treatments exhibited higher total N loss because light favored periphytic biofilm growth and enhanced ammonium (NH_(4)^(+)) assimilation and nitrification.Additionally,butachlor application resulted in the increased retention of NH_(4)^(+)-N and nitrate (NO_(3)^(-))-N and an increase in N loss via denitrification.The abundances of functional genes encoding enzymes such as ammonia monooxygenase,nitrite reductase,and nitrous oxide reductase were increased by butachlor application,favoring nitrification and denitrification processes.Overall,the results suggest that butachlor application leads to an increase in total N loss mainly through denitrification in paddy systems,particularly in the presence of periphytic biofilms.Thus,the results may provide valuable insights into the changes in periphytic biofilm growth and N cycling induced by butachlor,and future studies can further explore the potential implications of these changes in paddy soils.

Genetic variants in promoter region of TFR2 is associated with the risk of non-alcoholic fatty liver disease in a Chinese Han population:a case–control study

Background Iron overload is frequently observed in non-alcoholic fatty liver disease(NAFLD).Transferrin receptor 2(TFR2)is an important key factor in iron regulation.We aimed to investigate whether TFR2 single nucleotide polymorphisms(SNPs)contribute to susceptibility to NAFLD in a Chinese Han population.Methods Five tag SNPs(rs10247962,rs4434553,rs2075672,rs1052897,and rs3757859)in the TFR2 gene were selected and genotyped in a case–control study on participants who visited two affiliated hospitals of Fujian Medical University between June 2011 and August 2017.Propensity score matching and inverse probability of treatment weighting analyses were used to verify the risk associated with TFR2 SNPs.Results Logistic regression analyses suggested that subjects with the rs4434553 GA or GG genotype had a lower risk of NAFLD than those carrying the AA genotype(odds ratio=0.630,95%confidence interval=0.504–0.788).Moreover,the rs4434553 GA or GG genotype was negatively correlated with body mass index,hepatic steatosis index,and serum ferritin(b=-0.363,P=0.008;b=-1.040,P=0.009;b=-35.258,P=0.015,respectively),and positively associated with serum hepcidin level(b=35.308,P<0.001).Moreover,rs10247962 and rs1052897 had multiplicative interactions with age in relation to the risk of NAFLD(P for interactions,0.041 and 0.034,respectively).The cumulative effects of the rs10247962,rs1052897,and rs4434553 SNPs were positively associated with the risk of NAFLD(adjusted P_(trend)=0.012).Conclusions In this Chinese Han population,the rs4434553 polymorphism in TFR2 may be an independent influencing factor associated with the susceptibility to NAFLD.The ageing effect on the development of NAFLD may be inhibited by SNPs rs10247962 and rs1052897.