Memristor-based chaotic systems with infinite equilibria are interesting because they generate extreme multistability.Their initial state-dependent dynamics can be explained in a reduced-dimension model by converting ...Memristor-based chaotic systems with infinite equilibria are interesting because they generate extreme multistability.Their initial state-dependent dynamics can be explained in a reduced-dimension model by converting the incremental integration of the state variables into system parameters.However,this approach cannot solve memristive systems in the presence of nonlinear terms other than the memristor term.In addition,the converted state variables may suffer from a degree of divergence.To allow simpler mechanistic analysis and physical implementation of extreme multistability phenomena,this paper uses a multiple mixed state variable incremental integration(MMSVII)method,which successfully reconstructs a four-dimensional hyperchaotic jerk system with multiple cubic nonlinearities except for the memristor term in a three-dimensional model using a clever linear state variable mapping that eliminates the divergence of the state variables.Finally,the simulation circuit of the reduced-dimension system is constructed using Multisim simulation software and the simulation results are consistent with the MATLAB numerical simulation results.The results show that the method of MMSVII proposed in this paper is useful for analyzing extreme multistable systems with multiple higher-order nonlinear terms.展开更多
The nonlinear variation of wave is commonly seen in nearshore area,and the resulting seabed response and liquefaction are of high concern to coastal engineers.In this study,an analytical formula considering the nonlin...The nonlinear variation of wave is commonly seen in nearshore area,and the resulting seabed response and liquefaction are of high concern to coastal engineers.In this study,an analytical formula considering the nonlinear wave skewness and asymmetry is adopted to provide wave pressure on the seabed surface.The liquefaction depth attenuation coefficient and width growth coefficient are defined to quantitatively characterize the nonlinear effect of wave on seabed liquefaction.Based on the 2D full dynamic model of wave-induced seabed response,a detailed parametric study is carried out in order to evaluate the influence of the nonlinear variation of wave loadings on seabed liquefaction.Further,new empirical prediction formulas are proposed to fast predict the maximum liquefaction under nonlinear wave.Results indicate that(1)Due to the influence of wave nonlinearity,the vertical transmission of negative pore water pressure in the seabed is hindered,and therefore,the amplitude decreases significantly.(2)In general,with the increase of wave nonlinearity,the liquefaction depth of seabed decreases gradually.Especially under asymmetric and skewed wave loading,the attenuation of maximum seabed liquefaction depth is the most significant among all the nonlinear wave conditions.However,highly skewed wave can cause the liquefaction depth of seabed greater than that under linear wave.(3)The asymmetry of wave pressure leads to the increase of liquefaction width,whereas the influence of skewedness is not significant.(4)Compared with the nonlinear waveform,seabed liquefaction is more sensitive to the variation of nonlinear degree of wave loading.展开更多
Parity–time(PT) and quasi-anti-parity–time(quasi-APT) symmetric optical gyroscopes have been proposed recently which enhance Sagnac frequency splitting. However, the operation of gyroscopes at the exceptional point(...Parity–time(PT) and quasi-anti-parity–time(quasi-APT) symmetric optical gyroscopes have been proposed recently which enhance Sagnac frequency splitting. However, the operation of gyroscopes at the exceptional point(EP) is challenging due to strict fabrication requirements and experimental uncertainties. We propose a new quasi-APT-symmetric micro-optical gyroscope which can be operated at the EP by easily shifting the Kerr nonlinearity. A single resonator is used as the core sensitive component of the quasi-APT-symmetric optical gyroscope to reduce the size, overcome the strict structural requirements and detect small rotation rates. Moreover, the proposed scheme also has an easy readout method for the frequency splitting. As a result, the device achieves a frequency splitting 10~5 times higher than that of a classical resonant optical gyroscope with the Earth's rotation. This proposal paves the way for a new and valuable method for the engineering of micro-optical gyroscopes.展开更多
Nonlinear phononic crystals have attracted great interest because of their unique properties absent in linear phononic crystals.However,few researches have considered the bilinear nonlinearity as well as its consequen...Nonlinear phononic crystals have attracted great interest because of their unique properties absent in linear phononic crystals.However,few researches have considered the bilinear nonlinearity as well as its consequences in acoustic metamaterials.Hence,we introduce bilinear nonlinearity into acoustic metamaterials,and investigate the propagation behaviors of the fundamental and the second harmonic waves in the nonlinear acoustic metamaterials by discretization method,revealing the influence of the system parameters.Furthermore,we investigate the influence of partially periodic nonlinear acoustic metamaterials on the second harmonic wave propagation,and the results suggest that pass-band and band-gap can be transformed into each other under certain conditions.Our findings could be beneficial to the band gap control in nonlinear acoustic metamaterials.展开更多
Consider performing a sequence of Bernoulli trials (each resulting in either a success, denoted S, or a failure F, with a probability of p and q := 1 - p respectively) until one of m specific strings (or patterns) of ...Consider performing a sequence of Bernoulli trials (each resulting in either a success, denoted S, or a failure F, with a probability of p and q := 1 - p respectively) until one of m specific strings (or patterns) of consecutive outcomes is generated. This can be seen as a game where m players select one such pattern each and the one whose pattern occurs first wins. We present symbolic formulas for the m probabilities of winning, and for the mean number of trials and the corresponding standard deviation to complete this game. Several numerical examples are presented, including a search for optimal strategy.展开更多
The presence of anticrossings induced by coupling between two states causes curvature in energy levels, yielding a nonlinearity in the quantum system. When the system is driven back and forth along the bending energy ...The presence of anticrossings induced by coupling between two states causes curvature in energy levels, yielding a nonlinearity in the quantum system. When the system is driven back and forth along the bending energy levels, subharmonic transitions and energy shifts can be observed, which would cause a significant influence as the system is applied to quantum computing. In this paper, we study a longitudinally driven singlet-triplet(ST) system in a double quantum dot(DQD)system, and illustrate the consequences of nonlinearity by driving the system close to the anticrossings. We provide a straightforward theory to quantitatively describe the energy shift and subharmonics caused by nonlinearity, and find good agreement between our theoretical result and the numerical simulation. Our results reveal the existence of nonlinearity in the vicinity of anticrossings and provide a direct way of analytically assessing its impact, which can be applied to other quantum systems without excessive labor.展开更多
Dependent competing risks model is a practical model in the analysis of lifetime and failure modes.The dependence can be captured using a statistical tool to explore the re-lationship among failure causes.In this pape...Dependent competing risks model is a practical model in the analysis of lifetime and failure modes.The dependence can be captured using a statistical tool to explore the re-lationship among failure causes.In this paper,an Archimedean copula is chosen to describe the dependence in a constant-stress accelerated life test.We study the Archimedean copula based dependent competing risks model using parametric and nonparametric methods.The parametric likelihood inference is presented by deriving the general expression of likelihood function based on assumed survival Archimedean copula associated with the model parameter estimation.Combining the nonparametric estimation with progressive censoring and the non-parametric copula estimation,we introduce a nonparametric reliability estimation method given competing risks data.A simulation study and a real data analysis are conducted to show the performance of the estimation methods.展开更多
BACKGROUND Major depressive disorder(MDD)is a common and serious mental illness.Many novel genes in MDD have been characterized by high-throughput methods such as microarrays or sequencing.Recently,noncoding RNAs(ncRN...BACKGROUND Major depressive disorder(MDD)is a common and serious mental illness.Many novel genes in MDD have been characterized by high-throughput methods such as microarrays or sequencing.Recently,noncoding RNAs(ncRNAs)were suggested to be involved in the complicated environmental-genetic regulatory network of MDD occurrence;however,the interplay among RNA species,including protein-coding RNAs and ncRNAs,in MDD remains unclear.AIM To investigate the RNA expression datasets downloaded from a public database and construct a network based on differentially expressed long noncoding RNA(lncRNAs),microRNAs(miRNAs),and mRNAs between MDD and controls.METHODS Gene expression data were searched in NCBI Gene Expression Omnibus using the search term“major depressive disorder.”Six array datasets from humans were related to the search term:GSE19738,GSE32280,GSE38206,GSE52790,GSE76826,and GSE81152.These datasets were processed for initial assessment and subjected to quality control and differential expression analysis.Differentially expressed lncRNAs,miRNAs,and mRNAs were determined,Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analyses were performed,and protein-protein interaction network was generated.The results were analyzed for their association with MDD.RESULTS After analysis,3 miRNAs,12 lncRNAs,and 33 mRNAs were identified in the competing endogenous RNA network.Two of these miRNAs were earlier shown to be involved in psychiatric disorders,and differentially expressed mRNAs were found to be highly enriched in pathways related to neurogenesis and neuroplasticity as per Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analyses.The expression of hub gene fatty acid 2-hydroxylase was enriched,and the encoded protein was found to be involved in myelin formation,indicating that neurological development and signal transduction are involved in MDD pathogenesis.CONCLUSION The present study presents candidate nc RNAs involved in the neurogenesis and neuroplasticity pathways related to MDD.展开更多
BACKGROUND Stenting as a bridge to curative surgery(SBTS)for obstructing colon cancer(OCC)has been associated with possibly worse oncological outcomes.AIM To evaluate the recurrence patterns,survival outcomes,and colo...BACKGROUND Stenting as a bridge to curative surgery(SBTS)for obstructing colon cancer(OCC)has been associated with possibly worse oncological outcomes.AIM To evaluate the recurrence patterns,survival outcomes,and colorectal cancer(CRC)-specific death in patients undergoing SBTS for OCC.METHODS Data from 62 patients undergoing SBTS at a single tertiary centre over ten years between 2007 and 2016 were retrospectively examined.Primary outcomes were recurrence patterns,overall survival(OS),cancer-specific survival(CSS),and CRC-specific death.OS and CSS were estimated using the Kaplan-Meier curves.Competing risk analysis with cumulative incidence function(CIF)was used to estimate CRC-specific mortality with other cause-specific death as a competing event.Fine-Gray regressions were performed to determine prognostic factors of CRC-specific death.Univariate and multivariate subdistribution hazard ratios and their corresponding Wald test P values were calculated.RESULTS 28 patients(45.2%)developed metastases after a median period of 16 mo.Among the 18 patients with single-site metastases:Four had lung-only metastases(14.3%),four had liver-only metastases(14.3%),and 10 had peritoneum-only metastases(35.7%),while 10 patients had two or more sites of metastatic disease(35.7%).The peritoneum was the most prevalent(60.7%)site of metastatic involvement(17/28).The median follow-up duration was 46 mo.26(41.9%)of the 62 patients died,of which 16(61.5%)were CRC-specific deaths and 10(38.5%)were deaths owing to other causes. The 1-, 3-, and 5-year OS probabilities were 88%, 74%, and 59%;1-, 3-, and5-year CSS probabilities were 97%, 83%, and 67%. The highest CIF for CRC-specific death at 60 mowas liver-only recurrence (0.69). Liver-only recurrence, peritoneum-only recurrence, and two ormore recurrence sites were predictive of CRC-specific death.CONCLUSIONThe peritoneum was the most common metastatic site among patients undergoing SBTS. Liveronlyrecurrence, peritoneum-only recurrence, and two or more recurrence sites were predictors ofCRC-specific death.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant No.62071411)the Research Foundation of Education Department of Hunan Province,China(Grant No.20B567).
文摘Memristor-based chaotic systems with infinite equilibria are interesting because they generate extreme multistability.Their initial state-dependent dynamics can be explained in a reduced-dimension model by converting the incremental integration of the state variables into system parameters.However,this approach cannot solve memristive systems in the presence of nonlinear terms other than the memristor term.In addition,the converted state variables may suffer from a degree of divergence.To allow simpler mechanistic analysis and physical implementation of extreme multistability phenomena,this paper uses a multiple mixed state variable incremental integration(MMSVII)method,which successfully reconstructs a four-dimensional hyperchaotic jerk system with multiple cubic nonlinearities except for the memristor term in a three-dimensional model using a clever linear state variable mapping that eliminates the divergence of the state variables.Finally,the simulation circuit of the reduced-dimension system is constructed using Multisim simulation software and the simulation results are consistent with the MATLAB numerical simulation results.The results show that the method of MMSVII proposed in this paper is useful for analyzing extreme multistable systems with multiple higher-order nonlinear terms.
基金financially supported by the National Key Research and Development Program of China(Grant Nos.2021YFB2600700 and 2022YFC3102302)the Central Public-Interest Scientific Institution Basal Research Fund(Grant No.Y221007)+2 种基金the National Natural Science Foundation of China(Grant No.52271274)the Key Laboratory of Ministry of Education for Coastal Disaster and Protection,Hohai University(Grant No.202205)the Key Project of NSFC-Shandong Joint Research Funding POW3C(Grant No.U1906230).
文摘The nonlinear variation of wave is commonly seen in nearshore area,and the resulting seabed response and liquefaction are of high concern to coastal engineers.In this study,an analytical formula considering the nonlinear wave skewness and asymmetry is adopted to provide wave pressure on the seabed surface.The liquefaction depth attenuation coefficient and width growth coefficient are defined to quantitatively characterize the nonlinear effect of wave on seabed liquefaction.Based on the 2D full dynamic model of wave-induced seabed response,a detailed parametric study is carried out in order to evaluate the influence of the nonlinear variation of wave loadings on seabed liquefaction.Further,new empirical prediction formulas are proposed to fast predict the maximum liquefaction under nonlinear wave.Results indicate that(1)Due to the influence of wave nonlinearity,the vertical transmission of negative pore water pressure in the seabed is hindered,and therefore,the amplitude decreases significantly.(2)In general,with the increase of wave nonlinearity,the liquefaction depth of seabed decreases gradually.Especially under asymmetric and skewed wave loading,the attenuation of maximum seabed liquefaction depth is the most significant among all the nonlinear wave conditions.However,highly skewed wave can cause the liquefaction depth of seabed greater than that under linear wave.(3)The asymmetry of wave pressure leads to the increase of liquefaction width,whereas the influence of skewedness is not significant.(4)Compared with the nonlinear waveform,seabed liquefaction is more sensitive to the variation of nonlinear degree of wave loading.
基金Project supported by the National Natural Science Foundation of China (Grant Nos.62273115,62173105)the Fundamental Research Funds for the Central Universities (Grant No.3072022FSC0401)。
文摘Parity–time(PT) and quasi-anti-parity–time(quasi-APT) symmetric optical gyroscopes have been proposed recently which enhance Sagnac frequency splitting. However, the operation of gyroscopes at the exceptional point(EP) is challenging due to strict fabrication requirements and experimental uncertainties. We propose a new quasi-APT-symmetric micro-optical gyroscope which can be operated at the EP by easily shifting the Kerr nonlinearity. A single resonator is used as the core sensitive component of the quasi-APT-symmetric optical gyroscope to reduce the size, overcome the strict structural requirements and detect small rotation rates. Moreover, the proposed scheme also has an easy readout method for the frequency splitting. As a result, the device achieves a frequency splitting 10~5 times higher than that of a classical resonant optical gyroscope with the Earth's rotation. This proposal paves the way for a new and valuable method for the engineering of micro-optical gyroscopes.
基金Project supported by the National Key Research and Development program of China(Grant No.2020YFA0211400)the State Key Program of the National Natural Science of China(Grant No.11834008)+2 种基金the National Natural Science Foundation of China(Grant No.12174192)the Fund fromthe State Key Laboratory of Acoustics,Chinese Academy of Sciences(Grant No.SKLA202008)the Fund from the Key Laboratory of Underwater Acoustic Environment,Chinese Academy of Sciences(Grant No.SSHJ-KFKT-1701)。
文摘Nonlinear phononic crystals have attracted great interest because of their unique properties absent in linear phononic crystals.However,few researches have considered the bilinear nonlinearity as well as its consequences in acoustic metamaterials.Hence,we introduce bilinear nonlinearity into acoustic metamaterials,and investigate the propagation behaviors of the fundamental and the second harmonic waves in the nonlinear acoustic metamaterials by discretization method,revealing the influence of the system parameters.Furthermore,we investigate the influence of partially periodic nonlinear acoustic metamaterials on the second harmonic wave propagation,and the results suggest that pass-band and band-gap can be transformed into each other under certain conditions.Our findings could be beneficial to the band gap control in nonlinear acoustic metamaterials.
文摘Consider performing a sequence of Bernoulli trials (each resulting in either a success, denoted S, or a failure F, with a probability of p and q := 1 - p respectively) until one of m specific strings (or patterns) of consecutive outcomes is generated. This can be seen as a game where m players select one such pattern each and the one whose pattern occurs first wins. We present symbolic formulas for the m probabilities of winning, and for the mean number of trials and the corresponding standard deviation to complete this game. Several numerical examples are presented, including a search for optimal strategy.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 12074368, 92165207, 12034018 and 92265113)the Anhui Province Natural Science Foundation (Grant No. 2108085J03)。
文摘The presence of anticrossings induced by coupling between two states causes curvature in energy levels, yielding a nonlinearity in the quantum system. When the system is driven back and forth along the bending energy levels, subharmonic transitions and energy shifts can be observed, which would cause a significant influence as the system is applied to quantum computing. In this paper, we study a longitudinally driven singlet-triplet(ST) system in a double quantum dot(DQD)system, and illustrate the consequences of nonlinearity by driving the system close to the anticrossings. We provide a straightforward theory to quantitatively describe the energy shift and subharmonics caused by nonlinearity, and find good agreement between our theoretical result and the numerical simulation. Our results reveal the existence of nonlinearity in the vicinity of anticrossings and provide a direct way of analytically assessing its impact, which can be applied to other quantum systems without excessive labor.
基金Supported by the National Natural Science Foundation of China(12101476,12061091,11901134)the Fundamental Research Funds for the Central Universities(ZYTS23054,QTZX22054)+1 种基金the Yunnan Funda-mental Research Projects(202101AT070103)the Natural Science Basic Research Program of Shaanxi Province(2020JQ-285).
文摘Dependent competing risks model is a practical model in the analysis of lifetime and failure modes.The dependence can be captured using a statistical tool to explore the re-lationship among failure causes.In this paper,an Archimedean copula is chosen to describe the dependence in a constant-stress accelerated life test.We study the Archimedean copula based dependent competing risks model using parametric and nonparametric methods.The parametric likelihood inference is presented by deriving the general expression of likelihood function based on assumed survival Archimedean copula associated with the model parameter estimation.Combining the nonparametric estimation with progressive censoring and the non-parametric copula estimation,we introduce a nonparametric reliability estimation method given competing risks data.A simulation study and a real data analysis are conducted to show the performance of the estimation methods.
基金Supported by the National Key Research and Development Program of China,No.2020YFC2005500。
文摘BACKGROUND Major depressive disorder(MDD)is a common and serious mental illness.Many novel genes in MDD have been characterized by high-throughput methods such as microarrays or sequencing.Recently,noncoding RNAs(ncRNAs)were suggested to be involved in the complicated environmental-genetic regulatory network of MDD occurrence;however,the interplay among RNA species,including protein-coding RNAs and ncRNAs,in MDD remains unclear.AIM To investigate the RNA expression datasets downloaded from a public database and construct a network based on differentially expressed long noncoding RNA(lncRNAs),microRNAs(miRNAs),and mRNAs between MDD and controls.METHODS Gene expression data were searched in NCBI Gene Expression Omnibus using the search term“major depressive disorder.”Six array datasets from humans were related to the search term:GSE19738,GSE32280,GSE38206,GSE52790,GSE76826,and GSE81152.These datasets were processed for initial assessment and subjected to quality control and differential expression analysis.Differentially expressed lncRNAs,miRNAs,and mRNAs were determined,Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analyses were performed,and protein-protein interaction network was generated.The results were analyzed for their association with MDD.RESULTS After analysis,3 miRNAs,12 lncRNAs,and 33 mRNAs were identified in the competing endogenous RNA network.Two of these miRNAs were earlier shown to be involved in psychiatric disorders,and differentially expressed mRNAs were found to be highly enriched in pathways related to neurogenesis and neuroplasticity as per Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analyses.The expression of hub gene fatty acid 2-hydroxylase was enriched,and the encoded protein was found to be involved in myelin formation,indicating that neurological development and signal transduction are involved in MDD pathogenesis.CONCLUSION The present study presents candidate nc RNAs involved in the neurogenesis and neuroplasticity pathways related to MDD.
文摘BACKGROUND Stenting as a bridge to curative surgery(SBTS)for obstructing colon cancer(OCC)has been associated with possibly worse oncological outcomes.AIM To evaluate the recurrence patterns,survival outcomes,and colorectal cancer(CRC)-specific death in patients undergoing SBTS for OCC.METHODS Data from 62 patients undergoing SBTS at a single tertiary centre over ten years between 2007 and 2016 were retrospectively examined.Primary outcomes were recurrence patterns,overall survival(OS),cancer-specific survival(CSS),and CRC-specific death.OS and CSS were estimated using the Kaplan-Meier curves.Competing risk analysis with cumulative incidence function(CIF)was used to estimate CRC-specific mortality with other cause-specific death as a competing event.Fine-Gray regressions were performed to determine prognostic factors of CRC-specific death.Univariate and multivariate subdistribution hazard ratios and their corresponding Wald test P values were calculated.RESULTS 28 patients(45.2%)developed metastases after a median period of 16 mo.Among the 18 patients with single-site metastases:Four had lung-only metastases(14.3%),four had liver-only metastases(14.3%),and 10 had peritoneum-only metastases(35.7%),while 10 patients had two or more sites of metastatic disease(35.7%).The peritoneum was the most prevalent(60.7%)site of metastatic involvement(17/28).The median follow-up duration was 46 mo.26(41.9%)of the 62 patients died,of which 16(61.5%)were CRC-specific deaths and 10(38.5%)were deaths owing to other causes. The 1-, 3-, and 5-year OS probabilities were 88%, 74%, and 59%;1-, 3-, and5-year CSS probabilities were 97%, 83%, and 67%. The highest CIF for CRC-specific death at 60 mowas liver-only recurrence (0.69). Liver-only recurrence, peritoneum-only recurrence, and two ormore recurrence sites were predictive of CRC-specific death.CONCLUSIONThe peritoneum was the most common metastatic site among patients undergoing SBTS. Liveronlyrecurrence, peritoneum-only recurrence, and two or more recurrence sites were predictors ofCRC-specific death.
