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A two-sample Mendelian randomization study on the relationship of body weight,body mass index,and waist circumference with cardiac arrest
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作者 Tingting Xu Shaokun Wang +2 位作者 Liqiang Zhao Jiawen Wang Jihong Xing 《World Journal of Emergency Medicine》 2025年第2期129-135,共7页
BACKGROUND:This study aims to explore the causal relationship of body weight,body mass index(BMI),and waist circumference (WC) with the risk of cardiac arrest (CA) using two-sample Mendelian randomization (MR).METHODS... BACKGROUND:This study aims to explore the causal relationship of body weight,body mass index(BMI),and waist circumference (WC) with the risk of cardiac arrest (CA) using two-sample Mendelian randomization (MR).METHODS:Data were summarized using genome-wide association studies (GWAS).Twosample MR analyses were performed using the inverse variance weighting (IVW) method,the weighted median method,and the MR-Egger analysis.Heterogeneity test and sensitivity analysis were performed using Cochran’s Q test and the leave-one-out method,respectively.The Steiger test was used to detect reverse causality.Bayesian model-averaged MR was used to identify the most influential risk factors.RESULTS:A total of 13 GWAS data were collected for BMI,body weight and WC.IVW analyses showed a positive correlation of body weight,BMI,and WC with CA (all OR>1 and P<0.05),with MR-Egger and weighted median methods confirming the IVW findings.No horizontal pleiotropy or heterogeneity was observed.Sensitivity analysis indicated that no single nucleotide polymorphism(SNP) caused significant changes in overall causality.Bayesian model-averaged MR was also used to rank causality based on marginal inclusion probability (MIP),and the corresponding modelaveraged causal estimate (MACE) were confirmed,which indicated that WC (GWAS ID:ukb-b-9405)was the highest-ranked risk factor (MIP=0.119,MACE=0.011);its posterior probability was 0.057.A total of 14 sex-specific GWAS data on weight,BMI,and WC were analyzed in relationship with CA,and the MR results showed no significant effects of sex-specific factors.CONCLUSION:Body weight,BMI,and WC are causally associated with an increased risk of CA,with WC identified as the most important risk factor. 展开更多
关键词 Body weight Body mass index Waist circumference Cardiac arrest Mendelian randomization
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Site index determination using a time series of airborne laser scanning data
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作者 Maria Åsnes Moan Ole Martin Bollandsås +4 位作者 Svetlana Saarela Terje Gobakken Erik Næsset Hans Ole Ørka Lennart Noordermeer 《Forest Ecosystems》 2025年第1期93-103,共11页
Site index(SI)is determined from the top height development and is a proxy for forest productivity,defined as the expected top height for a given species at a certain index age.In Norway,an index age of 40 years is us... Site index(SI)is determined from the top height development and is a proxy for forest productivity,defined as the expected top height for a given species at a certain index age.In Norway,an index age of 40 years is used.By using bi-temporal airborne laser scanning(ALS)data,SI can be determined using models estimated from SI observed on field plots(the direct approach)or from predicted top heights at two points in time(the height differential approach).Time series of ALS data may enhance SI determination compared to conventional methods used in operational forest inventory by providing more detailed information about the top height development.We used longitudinal data comprising spatially consistent field and ALS data collected from training plots in 1999,2010,and 2022 to determine SI using the direct and height differential approaches using all combinations of years and performed an external validation.We also evaluated the use of data assimilation.Values of root mean square error obtained from external validation were in the ranges of 16.3%–21.4%and 12.8%–20.6%of the mean fieldregistered SI for the direct approach and the height differential approach,respectively.There were no statistically significant effects of time series length or the number of points in time on the obtained accuracies.Data assimilation did not result in any substantial improvement in the obtained accuracies.Although a time series of ALS data did not yield greater accuracies compared to using only two points in time,a larger proportion of the study area could be used in ALS-based determination of SI when a time series was available.This was because areas that were unsuitable for SI determination between two points in time could be subject to SI determination based on data from another part of the time series. 展开更多
关键词 Site index Time series Airborne laser scanning Direct approach Height differential approach Data assimilation
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On Wiener Index of Power of Paths and Cycles
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作者 LIU Sai-hua LI Xiao-rong 《Chinese Quarterly Journal of Mathematics》 2025年第1期49-58,共10页
The Wiener index of a graph is defined to be the sum of the distances of all pairs of vertices in the graph.The kth power G^(k) of a graph G is the graph on V(G)and two vertices are adjacent if and only if their dista... The Wiener index of a graph is defined to be the sum of the distances of all pairs of vertices in the graph.The kth power G^(k) of a graph G is the graph on V(G)and two vertices are adjacent if and only if their distance in G is less or equal to k.In this paper,we computed the Wiener index of the kth power of paths and cycles for any k≥2. 展开更多
关键词 Wiener index kth power of a path kth power of a cycle
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Early peripheral perfusion index predicts 28-day outcome in patients with septic shock 被引量:2
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作者 Cheng Chi Hao Gong +2 位作者 Kai Yang Peng Peng Xiaoxia Zhang 《World Journal of Emergency Medicine》 SCIE CAS CSCD 2024年第5期372-378,共7页
BACKGROUND:To investigate the prognostic value of the peripheral perfusion index(PPI)in patients with septic shock.METHODS:This prospective cohort study,conducted at the emergency intensive care unit of Peking Univers... BACKGROUND:To investigate the prognostic value of the peripheral perfusion index(PPI)in patients with septic shock.METHODS:This prospective cohort study,conducted at the emergency intensive care unit of Peking University People's Hospital,recruited 200 patients with septic shock between January 2023 and August 2023.These patients were divided into survival(n=84)and death(n=116)groups based on 28-day outcomes.Clinical evaluations included laboratory tests and clinical scores,with lactate and PPI values assessed upon admission to the emergency room and at 6 h and 12 h after admission.Risk factors associated with mortality were analyzed using univariate and multivariate Cox regression analyses.Receiver operator characteristic(ROC)curve was used to assess predictive performance.Mortality rates were compared,and Kaplan-Meier survival plots were created.RESULTS:Compared to the survival group,patients in the death group were older and had more severe liver damage and coagulation dysfunction,necessitating higher norepinephrine doses and increased fl uid replacement.Higher lactate levels and lower PPI levels at 0 h,6 h,and 12 h were observed in the death group.Multivariate Cox regression identifi ed prolonged prothrombin time(PT),decreased 6-h PPI and 12-h PPI as independent risk factors for death.The area under the curves for 6-h PPI and 12-h PPI were 0.802(95%CI 0.742-0.863,P<0.001)and 0.945(95%CI 0.915-0.974,P<0.001),respectively,which were superior to Glasgow Coma Scale(GCS),Sequential Organ Failure Assessment(SOFA)scores(0.864 and 0.928).Cumulative mortality in the low PPI groups at 6 h and 12 h was signifi cantly higher than in the high PPI groups(6-h PPI:77.52%vs.22.54%;12-h PPI:92.04%vs.13.79%,P<0.001).CONCLUSION:PPI may have value in predicting 28-day mortality in patients with septic shock. 展开更多
关键词 Peripheral perfusion index Septic shock PROGNOSIS Predictive value
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Association between the cumulative triglyceride-glucose index and the recurrence of atrial fibrillation after radiofrequency catheter ablation 被引量:1
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作者 Qing YAN Jia-Qi LIANG +5 位作者 Yi-De YUAN Yuan LI Jia-Li FAN Wen-Huan WU Pan XU Jia-Hong XUE 《Journal of Geriatric Cardiology》 SCIE CAS CSCD 2024年第2期200-210,共11页
BACKGROUND Triglyceride-glucose(TyG)index values are a new surrogate marker for insulin resistance.This study aimed to explore the relationship between cumulative TyG index values and atrial fibrillation(AF)recurrence... BACKGROUND Triglyceride-glucose(TyG)index values are a new surrogate marker for insulin resistance.This study aimed to explore the relationship between cumulative TyG index values and atrial fibrillation(AF)recurrence after radiofrequency catheter ablation(RFCA).METHODS A total of 576 patients with AF who underwent RFCA at the Second Affiliated Hospital of Xi'an Jiaotong University were included in this study.The participants were grouped based on cumulative TyG index values tertiles within 3 months after ablation.Cox regression and restricted cubic spline analyses were used to determine the relationship between cumulative TyG index values and AF recurrence.The predictive value of all risk factors was assessed by receiver operating curve analysis.RESULTS There were 375 patients completed the study(age:63.23±10.73 years,64.27%male).The risk of AF recurrence increased with increasing cumulative TyG index values tertiles.After adjusting for potential confounders,patients in the medium cumulative TyG index group[hazard ratio(HR)=4.949,95%CI:1.778–13.778,P=0.002]and the high cumulative TyG index group(HR=8.716,95%CI:3.371–22.536,P<0.001)had a higher risk of AF recurrence than those in the low cumulative TyG index group.The restricted cubic spline regression model also showed an increased risk of AF recurrence with increasing cumulative TyG index values.When considering cumulative TyG index values,left atrial diameter,and lactate dehydrogenase levels as a comprehensive factor,the model could effectively predict AF recurrence after RFCA[area under the curve(AUC)=0.847,95%CI:0.797–0.897,P<0.001].CONCLUSIONS Cumulative TyG index values were a risk factor for AF recurrence after RFCA.Monitoring longitudinal TyG index values may assist with optimized for risk stratification and outcome prediction for AF recurrence. 展开更多
关键词 ATRIAL FIBRILLATION index
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Predictive Value of Systemic Immune Inflammation Index, Aggregate Index of Systemic Inflammation, and Systemic Inflammation Response Index in Lower Extremity Deep Venous Thrombosis Following Severe Trauma
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作者 Peng-Fei Li Xin Lu +4 位作者 Yu-Qian Zhou Ke Wang Peng Yang Xiong-Hui Chen Feng Xu 《Chinese Medical Sciences Journal》 CAS CSCD 2024年第4期241-248,共8页
Objective Venous thromboembolism is a highly prevalent condition after polytrauma,and recognized as an important factor contributing to poor prognosis.The aim of this study was to investigate the risk factors for lowe... Objective Venous thromboembolism is a highly prevalent condition after polytrauma,and recognized as an important factor contributing to poor prognosis.The aim of this study was to investigate the risk factors for lower extremity deep venous thrombosis(LEDVT)in a severely traumatized population and to evaluate their predictive value for LEDVT.Methods This was a retrospective,single-center observational study.All subjects were severely traumatized patients who were admitted to the Traumatic Intensive Care Unit from January 2021 to May 2024.Based on Doppler ultrasound findings of both lower extremities from the time of injury to 30 days post-injury,patients who developed LEDVT were enrolled in the LEDVT group,and those who did not develop LEDVT were enrolled in the NLEDVT group.Demographic,clinical,and laboratory data were collected upon admission.Multivariable logistic regression analysis was performed to identify risk factors for LEDVT.Receiver operating characteristic(ROC)curve was used to evaluate the overall fit of the final model.Results There were 56 patients enrolled in the LEDVT group and 81 patients in the NLEDVT group.Age,Aggregate Index of Systemic Inflammation(AISI),Systemic Inflammation Response Index(SIRI),ICU length of stay,and albumin were identified as independent risk factors for LEDVT(all P<0.05).The area under their ROC curves were 0.604,0.657,0.694,0.668,and 0.405,respectively.Combined model for early clinical prediction of LEDVT in severely traumatized patients by age,SIRI,AISI,and albumin resulted in an area under the ROC curve of 0.805(95%CI:0.73-0.88,SE=0.037).Conclusion The combination of age,SIRI,AISI,and albumin has a predictive value for LEDVT in severely traumatized patients. 展开更多
关键词 severe trauma Systemtic Immune Inflammation index Aggregate index of Systemic Inflammation Systemic Inflammation Response index lower extremity deep venous thrombosis
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Analysis and construction of evaluation index system of inter-provincial electricity spot markets
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作者 Hao Yue Yu Zhang +5 位作者 Jiahao Guo Yang Hu Chengmei Wei Heping Jia Dunnan Liu Dunjian Xie 《Global Energy Interconnection》 EI CSCD 2024年第6期697-706,共10页
Because of the contradiction between the scale of new energy installations and the continuous load growth in the central and eastern regions of China,the balance problems of the electricity market are becoming increas... Because of the contradiction between the scale of new energy installations and the continuous load growth in the central and eastern regions of China,the balance problems of the electricity market are becoming increasingly prominent,and it is urgent to solve such problems through inter-provincial electricity spot markets.First,the development history and construction status of the inter-provincial electricity spot market are summarized;second,the mechanism design of the inter-provincial electricity spot market is sorted out in terms of the market operation framework,transaction declaration,and clearing methods;subsequently,the evaluation index system of the inter-provincial electricity spot market is constructed,including four themes of electricity mutual aid and support,new energy consumption,economic benefits of market-based allocation,and social benefits of market-based allocation;finally,the operation of the inter-provincial electricity spot market is comprehensively analyzed by the algorithm based on the market operation data of 2022,which proves the feasibility and practicality of the proposed index system. 展开更多
关键词 Electricity market Spot market Inter-provincial spot market Evaluation index system
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Genetic variation and selection of 10-year-old Eucalyptus camaldulensis based on wind damage index and wood properties
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作者 Xiuhua Shang Zhihua Wu +2 位作者 Xiaoming Li Youshuang Wang Peijian Zhang 《Journal of Forestry Research》 SCIE EI CAS CSCD 2024年第6期173-184,共12页
Typhoons are becoming frequent and intense with ongoing climate change,threatening ecological security and healthy forest development in coastal areas.Eucalyptus of a predominant introduced species in southern China,f... Typhoons are becoming frequent and intense with ongoing climate change,threatening ecological security and healthy forest development in coastal areas.Eucalyptus of a predominant introduced species in southern China,faces significant growth challenges because of typhoon.Therefore,it is vital to investigate the variation of related traits and select superior breeding materials for genetic improvement.Variance,genetic parameter,and correlation analyses were carried out on wind damage indices and eight wood proper-ties in 88 families from 11 provenances of 10-year-old Euca-lyptus camaldulensis.The selection index equation was used for evaluating multiple traits and selecting superior prov-enances and family lines as future breeding material.The results show that all traits were highly significantly differ-ent at provenance and family levels,with the wind damage index having the highest coefficient of genetic variation.The heritability of each trait ranged from 0.48 to 0.87,with the wind damage index,lignin and hemicellulose contents,and microfibril angle having the highest heritabilities.The wind damage index had a positive genetic correlation with wood density,a negative correlation with lignin content,a negative phenotypic correlation and a negative genetic correlation with microfibril angle.Wind damage index and genetic progress in the selection of eight wood traits varied from 7.2%to 614.8%.Three provenances and 12 superior families were selected.The genetic gains of the wind damage index were 10.2%and 33.9%for provenances and families,and these may be starting material for genetic modification for wind resistance in eucalyptus and for their dissemination to typhoon-prone coastal areas of southern China. 展开更多
关键词 Eucalyptus camaldulensis Wind damage index Wood properties Genetic variation Comprehensive selection
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OFDM with Generalized Cascade Index Modulation for Secure Communications
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作者 Hu Zeng Jin Xiaopin +3 位作者 Yao Yudong Chen Fangjiong Wan Dehuan Liu Yun 《China Communications》 SCIE CSCD 2024年第10期210-225,共16页
Cascade index modulation(CIM) is a recently proposed improvement of orthogonal frequency division multiplexing with index modulation(OFDM-IM) and achieves better error performance.In CIM, at least two different IM ope... Cascade index modulation(CIM) is a recently proposed improvement of orthogonal frequency division multiplexing with index modulation(OFDM-IM) and achieves better error performance.In CIM, at least two different IM operations construct a super IM operation or achieve new functionality. First, we propose a OFDM with generalized CIM(OFDM-GCIM) scheme to achieve a joint IM of subcarrier selection and multiple-mode(MM)permutations by using a multilevel digital algorithm.Then, two schemes, called double CIM(D-CIM) and multiple-layer CIM(M-CIM), are proposed for secure communication, which combine new IM operation for disrupting the original order of bits and symbols with conventional OFDM-IM, to protect the legitimate users from eavesdropping in the wireless communications. A subcarrier-wise maximum likelihood(ML) detector and a low complexity log-likelihood ratio(LLR) detector are proposed for the legitimate users. A tight upper bound on the bit error rate(BER) of the proposed OFDM-GCIM, D-CIM and MCIM at the legitimate users are derived in closed form by employing the ML criteria detection. Computer simulations and numerical results show that the proposed OFDM-GCIM achieves superior error performance than OFDM-IM, and the error performance at the eavesdroppers demonstrates the security of D-CIM and M-CIM. 展开更多
关键词 cascade index modulation low-complexity detector maximum likelihood OFDM physical layer security
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Surface phonon resonance:A new mechanism for enhancing photonic spin Hall effect and refractive index sensor
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作者 程杰 汪承龙 +3 位作者 李一铭 张亚林 刘胜利 董鹏 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第8期254-261,共8页
Metal-based surface plasmon resonance(SPR)plays an important role in enhancing the photonic spin Hall effect(SHE)and developing sensitive optical sensors.However,the very large negative permittivities of metals limit ... Metal-based surface plasmon resonance(SPR)plays an important role in enhancing the photonic spin Hall effect(SHE)and developing sensitive optical sensors.However,the very large negative permittivities of metals limit their applications beyond the near-infrared regime.In this work,we theoretically present a new mechanism to enhance the photonic SHE by taking advantage of SiC-supported surface phonon resonance(SPhR)in the mid-infrared regime.The transverse displacement of photonic SHE is very sensitive to the wavelength of incident light and the thickness of SiC layer.Under the optimal parameter setup,the calculated largest transverse displacement of SiC-based SPhR structure reaches up to 163.8 ym,which is much larger than the condition of SPR.Moreover,an NO_(2) gas sensor based on the SPhR-enhanced photonic SHE is theoretically proposed with the superior sensing performance.Both the intensity and angle sensitivity of this sensor can be effectively manipulated by varying the damping rate of SiC.The results may provide a promising paradigm to enhance the photonic SHE in the mid-infrared region and open up new opportunity of highly sensitive refractive index sensors. 展开更多
关键词 photonic spin Hall effect refractive index sensor surface phonon resonance SIC
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The influences of canopy temperature measuring on the derived crop water stress index
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作者 WANG Hongxi LI Fei +4 位作者 SHEN Hongtao LI Mengyu YIN Gongchao FANG Qin SHAO Liwei 《中国生态农业学报(中英文)》 CAS CSCD 北大核心 2024年第9期1503-1519,共17页
Crop water stress index(CWSI)is widely used for efficient irrigation management.Precise canopy temperature(T_(c))measurement is necessary to derive a reliable CWSI.The objective of this research was to investigate the... Crop water stress index(CWSI)is widely used for efficient irrigation management.Precise canopy temperature(T_(c))measurement is necessary to derive a reliable CWSI.The objective of this research was to investigate the influences of atmospheric conditions,settled height,view angle of infrared thermography,and investigating time of temperature measuring on the performance of the CWSI.Three irrigation treatments were used to create different soil water conditions during the 2020-2021 and 2021-2022 winter wheat-growing seasons.The CWSI was calculated using the CWSI-E(an empirical approach)and CWSI-T(a theoretical approach)based on the T_(c).Weather conditions were recorded continuously throughout the experimental period.The results showed that atmospheric conditions influenced the estimation of the CWSI;when the vapor pressure deficit(VPD)was>2000 Pa,the estimated CWSI was related to soil water conditions.The height of the installed infrared thermograph influenced the T_(c)values,and the differences among the T_(c)values measured at height of 3,5,and 10 m was smaller in the afternoon than in the morning.However,the lens of the thermometer facing south recorded a higher T_(c)than those facing east or north,especially at a low height,indicating that the direction of the thermometer had a significant influence on T_(c).There was a large variation in CWSI derived at different times of the day,and the midday measurements(12:00-15:00)were the most reliable for estimating CWSI.Negative linear relationships were found between the transpiration rate and CWSI-E(R^(2)of 0.3646-0.5725)and CWSI-T(R^(2)of 0.5407-0.7213).The relations between fraction of available soil water(FASW)with CWSI-T was higher than that with CWSI-E,indicating CWSI-T was more accurate for predicting crop water status.In addition,The R^(2)between CWSI-T and FASW at 14:00 was higher than that at other times,indicating that 14:00 was the optimal time for using the CWSI for crop water status monitoring.Relative higher yield of winter wheat was obtained with average seasonal values of CWSI-E and CWSI-T around 0.23 and 0.25-0.26,respectively.The CWSI-E values were more easily influenced by meteorological factors and the timing of the measurements,and using the theoretical approach to derive the CWSI was recommended for precise irrigation water management. 展开更多
关键词 Canopy temperature Measuring time Measuring height and direction Crop water stress index
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Independence Polynomials and the Merrifield-Simmons Index of Mono-Layer Cylindrical Grid Graphs
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作者 JI Lin-xing ZHANG Ke HU Wen-jun 《Chinese Quarterly Journal of Mathematics》 2024年第4期379-387,共9页
Research on the independence polynomial of graphs has been very active.However,the computational complexity of determining independence polynomials for general graphs remains NP-hard.Letα(G)be the independence number... Research on the independence polynomial of graphs has been very active.However,the computational complexity of determining independence polynomials for general graphs remains NP-hard.Letα(G)be the independence number of G and i(G;k)be the number of independent sets of order k in G,then the independence polynomial is defined as I(G;x)=∑_(k=0)^(α(G))i(G;k)x^(k),i(G;0)=1.In this paper,by utilizing the transfer matrix,we obtain an analytical expression for I(CGn;x)of mono-cylindrical grid graphs CGn and present a crucial proof of it.Moreover,we also explore the Merrifield-Simmons index and other properties of CGn. 展开更多
关键词 Independence polynomial Cylindrical grid graphs Transfer matrix Merrifield-Simmons index
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凉山州14个核桃品种主要经济指标及脂肪酸组成分析
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作者 金银春 任波 +2 位作者 胡定林 陈善波 余凌帆 《中国油脂》 北大核心 2025年第1期135-140,共6页
为全面评价、合理利用四川省凉山州现有核桃品种,对凉山州14个核桃品种的主要经济指标及脂肪酸组成进行了测定,计算了各指标变异系数和遗传多样性指数,并对各指标进行相关性分析和聚类分析。结果表明:14个核桃品种中,粗脂肪含量较高的... 为全面评价、合理利用四川省凉山州现有核桃品种,对凉山州14个核桃品种的主要经济指标及脂肪酸组成进行了测定,计算了各指标变异系数和遗传多样性指数,并对各指标进行相关性分析和聚类分析。结果表明:14个核桃品种中,粗脂肪含量较高的核桃品种有小圆、美姑大泡、冕漾等,蛋白质含量较高的核桃品种有陆佳、香酥、白鹤滩米核桃等;香酥为高油酸含量品种,利丰紫瓤、大凉山紫伊核桃晚熟2号为高亚油酸含量品种,盐源早、冬晚、利丰紫瓤为高α-亚麻酸含量品种,盐源早、冬晚、小圆的亚油酸与α-亚麻酸含量比值更接近4;出仁率、粗脂肪含量、棕榈酸含量的变异系数较低,均小于10%,说明这3个指标较稳定;主要经济指标与脂肪酸含量的遗传多样性指数的变化范围为1.57~2.14,其中,出仁率的遗传多样性指数最低,十七碳酸含量的遗传多样性指数最高;三径均值与单果质量存在极显著正相关性,蛋白质含量与α-亚麻酸含量存在显著负相关性,油酸含量与亚油酸含量存在极显著负相关性;经聚类分析,在欧氏距离为20时,14个核桃品种被分为2个组群,小圆、香酥聚为一组,其他12个品种聚为一组。综上,14个核桃品种均为当地的优良品种,可对油脂含量高、蛋白质含量高、脂肪酸比例合理及其他特异性指标有优势的品种有针对性地加以利用。 展开更多
关键词 凉山州 核桃 品种 经济指标 脂肪酸
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基于改进自编码解码网络的轨道不平顺评价方法
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作者 杨建伟 王小慧 +3 位作者 刘佩珊 杨飞 王金海 孙培文 《铁道学报》 北大核心 2025年第2期131-144,共14页
目前无砟轨道平顺性的评价方法只适用于中短波长,难以满足大范围动态复杂线路的变化需求。如果仅依靠单一波长轨检数据评价轨道状态,会导致其他波长局部波动或潜在病害不能被有效识别的现象。通过挖掘不同波长下的轨道不平顺信息,将深... 目前无砟轨道平顺性的评价方法只适用于中短波长,难以满足大范围动态复杂线路的变化需求。如果仅依靠单一波长轨检数据评价轨道状态,会导致其他波长局部波动或潜在病害不能被有效识别的现象。通过挖掘不同波长下的轨道不平顺信息,将深度学习方法与现有评价方法相融合,提出改进的自编码解码高斯生成对抗神经网络(DAGGAN)及自适应轨道质量指数方法(DAE_TQI),实现对轨道状态的实时监控。为验证方法的准确性和有效性,将其与其他方法进行对比,验证DAGGAN模型在识别单几何不平顺时的有效性,同时DAE_TQI方法可综合评价无砟轨道状态,结果可作为高速铁路轨道养护维修的理论依据。 展开更多
关键词 轨道不平顺 轨道质量指数 自编码解码网络 高斯对抗网络 自适应轨道质量指数
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正常肝脏组织摄取~(18)F-FAPI-04的影响因素分析
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作者 李阳 李艳 沈聪 《西安交通大学学报(医学版)》 北大核心 2025年第2期285-289,共5页
目的探讨正常肝脏组织摄取~(18)F-FAPI-04的影响因素。方法回顾性纳入行~(18)F-FAPI-04 PET/CT显像的患者77例,收集患者的既往病史,同时收集显像前1周内实验室检查,包括血细胞分类计数、肝功能和肾功能指标。手工测量~(18)F-FAPI-04 PET... 目的探讨正常肝脏组织摄取~(18)F-FAPI-04的影响因素。方法回顾性纳入行~(18)F-FAPI-04 PET/CT显像的患者77例,收集患者的既往病史,同时收集显像前1周内实验室检查,包括血细胞分类计数、肝功能和肾功能指标。手工测量~(18)F-FAPI-04 PET/CT图像上肝脏的最大标准摄取值(maximal standard uptake value,SUVmax),分析SUVmax与血液学指标的相关性。以肝脏的SUVmax为因变量,进行多因素线性回归,得到肝脏摄取~(18)F-FAPI-04的独立预测因素。结果肝脏SUVmax在是否吸烟、是否饮酒、是否化疗、有无活动性肿瘤及有无肝转移的组间差异均无统计学意义(P>0.05)。肝脏SUVmax与血细胞分类计数均无明显相关性(P>0.05),与谷丙转氨酶、γ-谷氨酰转肽酶、直接胆红素、球蛋白、血糖和肌酐正相关(r=0.196,P=0.047;r=0.180,P=0.027;r=0.196,P=0.015;r=0.171,P=0.032;r=0.296,P<0.001;r=0.270,P=0.001),与肾小球滤过率负相关(r=-0.209,P=0.009)。其中,血糖(β=0.100,P<0.001)、直接胆红素(β=0.021,P<0.001)和肌酐(β=0.003,P=0.018)是肝脏SUVmax的独立预测因子。结论肝脏摄取~(18)F-FAPI-04与谷丙转氨酶、γ-谷氨酰转肽酶、直接胆红素、球蛋白、血糖和肌酐呈正相关,与肾小球滤过率呈负相关。其中血糖、直接胆红素和肌酐是影响肝脏摄取~(18)F-FAPI-04的独立预测因子。 展开更多
关键词 PET/CT ~(18)F-FAPI-04 血细胞分类计数 肝功能指标 肾功能指标
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我国优秀中短距离游泳运动员基础体能评价指标体系的构建与标准的建立 被引量:1
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作者 廖婷 师建伟 +1 位作者 王明波 闫琪 《武汉体育学院学报》 北大核心 2025年第2期69-78,共10页
目的:构建游泳项目基础体能的评价指标体系与评分标准,为我国游泳运动员开展基础体能训练提供参考。方法:采用德尔菲法构建我国中短距离游泳运动员基础体能评价指标体系,并计算各指标权重;采用测试法收集我国国家游泳队运动员相关指标数... 目的:构建游泳项目基础体能的评价指标体系与评分标准,为我国游泳运动员开展基础体能训练提供参考。方法:采用德尔菲法构建我国中短距离游泳运动员基础体能评价指标体系,并计算各指标权重;采用测试法收集我国国家游泳队运动员相关指标数据,应用百分位数法与累进计分法建立我国优秀中短距离游泳运动员的基础体能测试评价标准;并绘制ROC曲线探究基础体能评价标准总评分与运动员效率状态的关联性。结果:(1)基于国家游泳队现实基础及相关专家意见,构建了符合我国优秀中短距离游泳运动员现状的基础体能评价指标体系,包括4个一级指标、10个二级指标、10个三级指标。(2)根据对47名国家游泳队运动员进行为期近一年的体能测试,结合不同专项,制定了各单项指标评分标准及综合等级评分标准,评价标准经回代检验结果客观有效。(3)ROC曲线下面积为0.792(95%CI 0.609~0.916,P=0.001),表明该评价标准模型具有一定的预测能力。结论:我国优秀中短距离游泳运动员的基础体能评价指标体系具有可操作性和实用性,评价标准为我国优秀中短距离游泳运动员基础体能训练提供了重要的导向和参考价值。同时,评价标准模型对于优秀中短距离游泳运动员的竞技表现,显示出一定的预测价值。 展开更多
关键词 游泳运动员 体能测试 评价指标体系 评分标准 德尔菲法
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基于遥感指数的我国西部矿区生态质量监测——以彬长矿区为例 被引量:1
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作者 姚顽强 李悠 +4 位作者 郑俊良 蔺小虎 相里海龙 惠伯辰 李文欣 《金属矿山》 北大核心 2025年第1期259-266,共8页
我国西部矿区是煤炭资源开采的主要地区,也是最具代表性的生态脆弱区,探讨西部矿区自然生态环境的演变趋势及影响机制,对于矿区自然环境保护与有序恢复有着重要意义。以彬长矿区为例,通过遥感和GIS技术,利用Sentinel-2和Landsat 8遥感... 我国西部矿区是煤炭资源开采的主要地区,也是最具代表性的生态脆弱区,探讨西部矿区自然生态环境的演变趋势及影响机制,对于矿区自然环境保护与有序恢复有着重要意义。以彬长矿区为例,通过遥感和GIS技术,利用Sentinel-2和Landsat 8遥感影像数据,基于遥感生态指数(Remote Sensing Ecological Index,RSEI)模型,在深入剖析该矿区土地利用/覆被变化(Land Use/Cover Change,LUCC)和生态环境时空演变的基础上,分析了该矿区LUCC的生态质量。结果表明:①2017—2022年矿区LUCC结构上出现明显的转移特征,形成以林地、耕地和建设用地为主的新LUCC格局,并伴随着林地大范围转出为耕地和建设用地的情况,转移量约191.04 km^(2)。②5 a中,矿区生态环境质量呈下降趋势,RSEI由0.54降至0.47,研究发现矿区生态环境质量主要受绿度和干度指标因子影响。③2017—2022年矿区生态环境质量改善的面积占总面积的9%,生态环境质量恶化的面积占总面积的22%,分析结果可为西部矿区生态环境保护和修复提供参考。 展开更多
关键词 生态修复 遥感 GIS 遥感生态指数 土地利用/覆被变化 生态质量
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基于连续分布方向图和改进的Poincaré Index的指纹分类 被引量:20
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作者 聂桂军 吴陈 +1 位作者 叶锡君 徐荣青 《电子学报》 EI CAS CSCD 北大核心 2006年第5期947-952,共6页
本文提出了指纹连续分布方向图(场)的概念及其算法,连续分布方向图具有很好的连续性、渐变性、抗噪性和较高的精确度;对经典的PoincaréIndex计算公式和指纹奇异点检测算法进行了改进,改进后的PoincaréIndex不仅能精确表示向... 本文提出了指纹连续分布方向图(场)的概念及其算法,连续分布方向图具有很好的连续性、渐变性、抗噪性和较高的精确度;对经典的PoincaréIndex计算公式和指纹奇异点检测算法进行了改进,改进后的PoincaréIndex不仅能精确表示向量场的旋转角度,而且还能精确表示向量场的旋转方向,能够在像素级水平精确定位指纹奇异点(core点和delta点).在此基础上,提出了一种新的基于连续分布方向图和改进的PoincaréIn-dex的5类自动指纹分类算法,在江苏科技大学指纹库(含4000幅指纹)上的分类结果表明,本算法能抗任意角度的指纹图像旋转,成功地解决了指纹分类中的图像平移、旋转和形变不变性问题,分类正确率达到97.05%,具有较好的健壮性,满足实用要求. 展开更多
关键词 自动指纹识别系统 指纹分类 连续分布方向图 奇异点检测 POINCARÉ index
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旱地与补灌条件下不同基因型小麦耐旱性评价
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作者 孙宪印 吕广德 +9 位作者 亓晓蕾 徐加利 孙盈盈 米勇 牟秋焕 尹逊栋 张继波 王瑞霞 钱兆国 高明刚 《干旱地区农业研究》 北大核心 2025年第1期13-20,共8页
为在干旱胁迫条件下从不同小麦品系中筛选耐旱性强且具有高产稳产特性的基因型,采用随机区组设计,于2022—2023年在泰安市农业科学院马庄试验农场开展田间试验,以14个不同基因型小麦品系为材料,设置自然干旱和补灌条件2个处理,以旱地与... 为在干旱胁迫条件下从不同小麦品系中筛选耐旱性强且具有高产稳产特性的基因型,采用随机区组设计,于2022—2023年在泰安市农业科学院马庄试验农场开展田间试验,以14个不同基因型小麦品系为材料,设置自然干旱和补灌条件2个处理,以旱地与补灌条件下产量为基础,采用平均产量(MP)、几何平均产量(GMP)、抗旱系数(DRC)、抗旱指数(DRI)和干旱耐受指数(STI)共5个抗旱性指标对不同品系进行比较和抗旱性分级。结果表明,对比不同品系的干旱指标数值的大小与位次变化,V7、V14、V2和V12基因型排名靠前,具有高产、稳产特点。同时STI、GMP、MP指标与旱地产量和补灌产量均呈极显著正相关关系且表现出较好的产量一致性;主成分分析和聚类分析结果均进一步明确了这些基因型的耐旱及高产稳产特性。综上,在干旱与补灌条件下,STI、GMP、MP和DRI指标可用于耐旱高产基因型的鉴别和分级,综合利用5种抗旱指标筛选出耐旱高产品系分别为V7、V14、V2和V12,各品系抗旱性级别分别为1、2、2级和1级。 展开更多
关键词 小麦 基因型 干旱胁迫 主成分分析 聚类分析 耐旱性指标
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基于驾驶负荷的高速公路地下互通匝道平纵设计指标研究
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作者 王佐 张驰 +2 位作者 焦昱棋 林宣财 颜家强 《隧道建设(中英文)》 北大核心 2025年第2期256-267,共12页
为研究地下互通匝道基本路段平纵设计指标,招募10名驾驶人进行仿真试验,基于UC-win/Road建立各工况的仿真模型,通过驾驶模拟仿真试验,得到8种不同平纵组合工况下的驾驶人行车特性以及心生理数据,以心率增长率作为驾驶负荷表征参数,并根... 为研究地下互通匝道基本路段平纵设计指标,招募10名驾驶人进行仿真试验,基于UC-win/Road建立各工况的仿真模型,通过驾驶模拟仿真试验,得到8种不同平纵组合工况下的驾驶人行车特性以及心生理数据,以心率增长率作为驾驶负荷表征参数,并根据实测车辆的驾驶人心率增长率数据进行标定。采用回归分析得到地下互通匝道纵坡路段、平曲线路段、弯坡组合路段的平纵几何设计指标、行车速度与驾驶负荷的理论模型,根据驾驶负荷阈值计算得到地下互通匝道的圆曲线半径和纵坡的指标计算值,结合最大超高得到圆曲线半径的指标推荐值。试验结果表明:1)左偏曲线平均行车速度比右偏曲线高5.6%,平均心率增长率增加9.0%;下坡路段平均行车速度比上坡路段高3.2%,平均心率增长率增加6.8%。2)驾驶人在左偏平曲线路段的驾驶负荷高于右偏平曲线路段,下坡路段的驾驶负荷高于上坡路段。3)在设计速度为40 km·h^(-1)的情况下,基于驾驶负荷考虑地下互通匝道下坡路段的安全坡度值为4.56%,上坡路段的安全坡度值为5.35%。4)地下互通匝道圆曲线半径推荐指标取值为地上互通设计指标的1.17~2.00倍,且差异随纵坡坡度及设计速度的增加而逐渐增大。 展开更多
关键词 高速公路 地下互通匝道 几何设计指标 驾驶仿真 驾驶负荷
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