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Predictive Ability of Hypertriglyceridemic Waist,Hypertriglyceridemic Waist-to-Height Ratio,and Waist-to-Hip Ratio for Cardiometabolic Risk Factors Clustering Screening among Chinese Children and Adolescents
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作者 XIAO Tian Li YUAN Shu Qian +6 位作者 GAO Jing Yu Julien SBaker YANG Yi De WANG Xi Jie ZHENG Chan Juan DONG Yan Hui ZOU Zhi Yong 《Biomedical and Environmental Sciences》 SCIE CAS CSCD 2024年第3期233-241,共9页
Objective Hypertriglyceridemic waist(HW),hypertriglyceridemic waist-to-height ratio(HWHtR),and waist-to-hip ratio(WHR)have been shown to be indicators of cardiometabolic risk factors.However,it is not clear which indi... Objective Hypertriglyceridemic waist(HW),hypertriglyceridemic waist-to-height ratio(HWHtR),and waist-to-hip ratio(WHR)have been shown to be indicators of cardiometabolic risk factors.However,it is not clear which indicator is more suitable for children and adolescents.We aimed to investigate the relationship between HW,HWHtR,WHR,and cardiovascular risk factors clustering to determine the best screening tools for cardiometabolic risk in children and adolescents.Methods This was a national cross-sectional study.Anthropometric and biochemical variables were assessed in approximately 70,000 participants aged 6–18 years from seven provinces in China.Demographics,physical activity,dietary intake,and family history of chronic diseases were obtained through questionnaires.ANOVA,χ2 and logistic regression analysis was conducted.Results A significant sex difference was observed for HWHtR and WHR,but not for HW phenotype.The risk of cardiometabolic health risk factor clustering with HW phenotype or the HWHtR phenotype was significantly higher than that with the non-HW or non-HWHtR phenotypes among children and adolescents(HW:OR=12.22,95%CI:9.54-15.67;HWHtR:OR=9.70,95%CI:6.93-13.58).Compared with the HW and HWHtR phenotypes,the association between risk of cardiometabolic health risk factors(CHRF)clustering and high WHR was much weaker and not significant(WHR:OR=1.14,95%CI:0.97-1.34).Conclusion Compared with HWHtR and WHR,the HW phenotype is a more convenient indicator with higher applicability to screen children and adolescents for cardiovascular risk factors. 展开更多
关键词 Hypertriglyceridemic waist Waist-to-hip ratio Children and adolescents China Hypertriglyceridemic waist-to-height ratio Cardiovascular risk factors
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A high resolution inversion method for fluid factor with dynamic dryrock V_(P)/V_(S) ratio squared
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作者 Lin Zhou Jian-Ping Liao +3 位作者 Xing-Ye Liu Pu Wang Ya-Nan Guo Jing-Ye Li 《Petroleum Science》 SCIE EI CSCD 2023年第5期2822-2834,共13页
As an important indicator parameter of fluid identification,fluid factor has always been a concern for scholars.However,when predicting Russell fluid factor or effective pore-fluid bulk modulus,it is necessary to intr... As an important indicator parameter of fluid identification,fluid factor has always been a concern for scholars.However,when predicting Russell fluid factor or effective pore-fluid bulk modulus,it is necessary to introduce a new rock skeleton parameter which is the dry-rock VP/VS ratio squared(DVRS).In the process of fluid factor calculation or inversion,the existing methods take this parameter as a static constant,which has been estimated in advance,and then apply it to the fluid factor calculation and inversion.The fluid identification analysis based on a portion of the Marmousi 2 model and numerical forward modeling test show that,taking the DVRS as a static constant will limit the identification ability of fluid factor and reduce the inversion accuracy.To solve the above problems,we proposed a new method to regard the DVRS as a dynamic variable varying with depth and lithology for the first time,then apply it to fluid factor calculation and inversion.Firstly,the exact Zoeppritz equations are rewritten into a new form containing the fluid factor and DVRS of upper and lower layers.Next,the new equations are applied to the four parameters simultaneous inversion based on the generalized nonlinear inversion(GNI)method.The testing results on a portion of the Marmousi 2 model and field data show that dynamic DVRS can significantly improve the fluid factor identification ability,effectively suppress illusion.Both synthetic and filed data tests also demonstrate that the GNI method based on Bayesian deterministic inversion(BDI)theory can successfully solve the above four parameter simultaneous inversion problem,and taking the dynamic DVRS as a target inversion parameter can effectively improve the inversion accuracy of fluid factor.All these results completely verified the feasibility and effectiveness of the proposed method. 展开更多
关键词 Fluid factor Dry-rock V_(P)/V_(S)ratio squared(DVRS) Dynamic variable Multiple parameters simultaneous inversion Generalized nonlinear inversion(GNI)
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Hybrid Multi-Infeed Interaction Factor Calculation Method Considering Voltage Regulation Control Characteristics of Voltage Source Converter
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作者 Shan Liu Chengbin Chi +3 位作者 Fengze Han Yanan Wu Lin Zhu Tuo Wang 《Energy Engineering》 EI 2024年第8期2257-2273,共17页
Voltage source converter based high voltage direct current(VSC-HVDC)can participate in voltage regulation by flexible control to help maintain the voltage stability of the power grid.In order to quantitatively evaluat... Voltage source converter based high voltage direct current(VSC-HVDC)can participate in voltage regulation by flexible control to help maintain the voltage stability of the power grid.In order to quantitatively evaluate its influence on the voltage interaction between VSC-HVDC and line commutated converter based high voltage direct current(LCC-HVDC),this paper proposes a hybrid multi-infeed interaction factor(HMIIF)calculation method considering the voltage regulation control characteristics of VSC-HVDC.Firstly,for a hybrid multi-infeed high voltage direct current system,an additional equivalent operating admittance matrix is constructed to characterize HVDC equipment characteristics under small disturbance.Secondly,based on the characteristic curve between the reactive power and the voltage of a certain VSC-HVDC project,the additional equivalent operating admittance of VSC-HVDC is derived.The additional equivalent operating admittance matrix calculation method is proposed.Thirdly,the equivalent bus impedance matrix is obtained by modifying the alternating current(AC)system admittance matrix with the additional equivalent operating admittance matrix.On this basis,the HMIIF calculation method based on the equivalent bus impedance ratio is proposed.Finally,the effectiveness of the proposed method is verified in a hybrid dual-infeed high voltage direct current system constructed in Power Systems Computer Aided Design(PSCAD),and the influence of voltage regulation control on HMIIF is analyzed. 展开更多
关键词 Hybrid multi-infeed high voltage direct current system hybrid multi-infeed interaction factor control modes equivalent node impedance ratio voltage interaction characteristics
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Analysis of Characteristics of Snow Accumulation and Its Meteorological Influencing Factors during a Snowstorm Process in Ulanqab City
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作者 Nan ZHAO Xinyu CHEN 《Meteorological and Environmental Research》 2024年第2期10-13,21,共5页
Based on the data of national observation stations of CMISS system,artificial encrypted observation data of snow depth,ERA5 reanalysis data,the snowfall process in Ulanqab City from March 17 to 19,2022 was analyzed.It... Based on the data of national observation stations of CMISS system,artificial encrypted observation data of snow depth,ERA5 reanalysis data,the snowfall process in Ulanqab City from March 17 to 19,2022 was analyzed.It is found that the influencing system of the snowfall process was upper-air trough combined with ground inverted trough.Snowfall was not proportional to snow depth,and the relationship between the maximum snow depth and total snowfall varied in different value intervals.A large intensity of snowfall was a necessary condition for the formation of abundant accumulated snow when ground temperature was higher than 0℃.After the formation of accumulated snow,ground temperature changed less,and it was easy to produce accumulated snow as ground temperature was lower.The lower the temperature,the more conducive to the generation of accumulated snow. 展开更多
关键词 SNOWSTORM Accumulated snow Snow-to-liquid ratio Influencing factors
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Binary Phase Shaping and SHG Contrast Ratios
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作者 Tingyao Xiong 《Journal of Applied Mathematics and Physics》 2024年第8期3026-3035,共10页
Finding binary sequences with Large SHG ratios is very important in the field of ultrafast science, biomedical optics, high-resolution microscopy and label-free imaging. In this paper, we have demonstrated the relatio... Finding binary sequences with Large SHG ratios is very important in the field of ultrafast science, biomedical optics, high-resolution microscopy and label-free imaging. In this paper, we have demonstrated the relation between the SHG contrast ratio and the traditional Merit Factor values. And in the light from known results in Merit Factor Problems, we have shown that Legendre Sequences or Jacobi Sequences, are still the best candidates to obtain binary sequences with large SHG contrast ratios. The authors also discussed the SHG behaviors on some sequences obtained from cyclotomic classes over the finite field GF (2l) . 展开更多
关键词 Binary Phase Shaping Binary Sequences SHG Contrast ratio Merit factor
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Estimation of quality factors by energy ratio method 被引量:1
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作者 王宗俊 曹思远 +5 位作者 张浩然 曲英铭 袁殿 杨金浩 张德龙 邵冠铭 《Applied Geophysics》 SCIE CSCD 2015年第1期86-92,122,123,共9页
The quality factor Q, which reflects the energy attenuation of seismic waves in subsurface media, is a diagnostic tool for hydrocarbon detection and reservoir characterization. In this paper, we propose a new Q extrac... The quality factor Q, which reflects the energy attenuation of seismic waves in subsurface media, is a diagnostic tool for hydrocarbon detection and reservoir characterization. In this paper, we propose a new Q extraction method based on the energy ratio before and after the wavelet attenuation, named the energy-ratio method(ERM). The proposed method uses multipoint signal data in the time domain to estimate the wavelet energy without invoking the source wavelet spectrum, which is necessary in conventional Q extraction methods, and is applicable to any source wavelet spectrum; however, it requires high-precision seismic data. Forward zero-offset VSP modeling suggests that the ERM can be used for reliable Q inversion after nonintrinsic attenuation(geometric dispersion, refl ection, and transmission loss) compensation. The application to real zero-offset VSP data shows that the Q values extracted by the ERM and spectral ratio methods are identical, which proves the reliability of the new method. 展开更多
关键词 Quality factor Q energy ratio time domain seismic wavelet spectral ratio method
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Therapeutic effect of nerve growth factor on cerebral infarction in dogs using the hemisphere anomalous volume ratio of diffusion-weighted magnetic resonance imaging 被引量:9
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作者 Yong Wang Hui Zhang +5 位作者 Zhe Wang Zuojun Geng Huaijun Liu Haiqing Yang Peng Song Qing Liu 《Neural Regeneration Research》 SCIE CAS CSCD 2012年第24期1873-1880,共8页
A model of focal cerebral ischemic infarction was established in dogs through middle cerebral artery occlusion of the right side.Thirty minutes after occlusion,models were injected with nerve growth factor adjacent to... A model of focal cerebral ischemic infarction was established in dogs through middle cerebral artery occlusion of the right side.Thirty minutes after occlusion,models were injected with nerve growth factor adjacent to the infarct locus.The therapeutic effect of nerve growth factor against cerebral infarction was assessed using the hemisphere anomalous volume ratio,a quantitative index of diffusion-weighted MRI.At 6 hours,24 hours,7 days and 3 months after modeling,the hemisphere anomalous volume ratio was significantly reduced after treatment with nerve growth factor. Hematoxylin-eosin staining,immunohistochemistry,electron microscopy and neurological function scores showed that infarct defects were slightly reduced and neurological function significantly improved after nerve growth factor treatment.This result was consistent with diffusion-weighted MRI measurements.Experimental findings indicate that nerve growth factor can protect against cerebral infarction,and that the hemisphere anomalous volume ratio of diffusion-weighted MRI can be used to evaluate the therapeutic effect. 展开更多
关键词 diffusion-weighted MRI nerve growth factor hemisphere anomalous volume ratio cerebral infarction treatment NEUROPROTECTION brain regeneration neural regeneration
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Q-factor estimation in CMP gather and the continuous spectral ratio slope method 被引量:4
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作者 Wu Zong-Wei Wu Yi-Jia +1 位作者 Guo Si Xu Ming-Hua 《Applied Geophysics》 SCIE CSCD 2018年第3期481-490,共10页
The attenuation factor or quality factor(Q-factor or Q) has been used to measure the energy attenuation of seismic waves propagating in underground media. Many methods are used to estimate the Q-factor. We propose a m... The attenuation factor or quality factor(Q-factor or Q) has been used to measure the energy attenuation of seismic waves propagating in underground media. Many methods are used to estimate the Q-factor. We propose a method to calculate the Q-factor based on the prestack Q-factor inversion and the generalized S-transform. The proposed method specifies a standard primary wavelet and calculates the cumulative Q-factors; then, it finds the interlaminar Q-factors using the relation between Q and offset(QVO) and the Dix formula. The proposed method is alternative to methods that calculate interlaminar Q-factors after horizon picking. Because the frequency spectrum of each horizon can be extracted continuously on a 2D time–frequency spectrum, the method is called the continuous spectral ratio slope(CSRS) method. Compared with the other Q-inversion methods, the method offers nearly effortless computations and stability, and has mathematical and physical significance. We use numerical modeling to verify the feasibility of the method and apply it to real data from an oilfield in Ahdeb, Iraq. The results suggest that the resolution and spatial stability of the Q-profile are optimal and contain abundant interlaminar information that is extremely helpful in making lithology and fluid predictions. 展开更多
关键词 Quality factor PRESTACK Q ESTIMATION generalized S transform spectral ratio SLOPE METHOD Q versus offset
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Calibration of LRFD Format for Steel Jacket OffshorePlatform in China Offshore Area(2): Load, Resistance and Load Combination Factors 被引量:1
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作者 周道成 段忠东 欧进萍 《China Ocean Engineering》 SCIE EI 2006年第2期199-212,共14页
Adopting the load and resistance factor design format, the design method for steel jaeket platform structures is developed. Firstly, the limit state equations and design format for steel jacket platform structures are... Adopting the load and resistance factor design format, the design method for steel jaeket platform structures is developed. Firstly, the limit state equations and design format for steel jacket platform structures are introduced. Then, the ratio of live load effect to dead load effect is estimated. The target reliabilities for design of offshore structures in China offshore area are calibrated by past practice in API RP2A-WSD code. The load and resistance factors are optimized by minimizing the difference within the target reliability and the resulting reliability over the range of load effect ratios. Considering the concurrence of different loads, load combination factors are obtained through an optimization process, and the relation between the load combination factor and load correlation coefficient is established. Finally, the design formulae for steel jacket structures in China offshore area are recommended. 展开更多
关键词 steel jacket offshore platform load effect ratio target reliability load and resistance factor load combination factor
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Branched-chain amino acids to tyrosine ratio value as a potential prognostic factor for hepatocellular carcinoma 被引量:10
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作者 Toru Ishikawa 《World Journal of Gastroenterology》 SCIE CAS CSCD 2012年第17期2005-2008,共4页
The prognosis of hepatocellular carcinoma(HCC) depends on tumor extension as well as hepatic function.Hepatic functional reserve is recognized as a factor affecting survival in the treatment of HCC;the ChildPugh class... The prognosis of hepatocellular carcinoma(HCC) depends on tumor extension as well as hepatic function.Hepatic functional reserve is recognized as a factor affecting survival in the treatment of HCC;the ChildPugh classif ication system is the most extensively used method for assessing hepatic functional reserve in patients with chronic liver disease,using serum albumin level to achieve accurate assessment of the status of protein metabolism.However,insuff icient attention has been given to the status of amino acid(AA) metabolism in chronic liver disease and HCC.Fischer's ratio is the molar ratio of branched-chain AAs(BCAAs:leucine,valine,isoleucine) to aromatic AAs(phenylalanine,tyrosine) and is important for assessing liver metabolism,hepatic functional reserve and the severity of liver dysfunction.Although this ratio is diff icult to determine in clinical situations,BCAAs/tyrosine molar concentration ratio(BTR) has been proposed as a simpler substitute.BTR correlates with various liver function examinations,including markers of hepatic f ibrosis,hepatic blood flow and hepatocyte function,and can thus be considered as reflecting the degree of hepatic impairment.This manuscript examines the literature to clarify whether BTR can serve as a prognostic factor for treatment of HCC. 展开更多
关键词 Branched-chain amino acids to tyrosine ratio Fischer's ratio Prognostic factor Hepatocellular carcinoma
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Crude oil cracking in deep reservoirs:A review of the controlling factors and estimation methods 被引量:1
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作者 Yu Qi Chun-Fang Cai +2 位作者 Peng Sun Dao-Wei Wang Hong-Jian Zhu 《Petroleum Science》 SCIE EI CAS CSCD 2023年第4期1978-1997,共20页
The natural cracking of crude oils in deep reservoirs has gained great interest due to continuously increasing depth of petroleum exploration and exploitation.Complex oil compositions and surroundings as well as compl... The natural cracking of crude oils in deep reservoirs has gained great interest due to continuously increasing depth of petroleum exploration and exploitation.Complex oil compositions and surroundings as well as complicated geological evolutions make oil cracking in nature much more complex than industrial pyrolysis.So far,numerous studies,focused on this topic,have made considerable progress although there still exist some drawbacks.However,a comprehensive review on crude oil cracking is yet to be conducted.This article systematically reviews the controlling factors of oil cracking from six aspects,namely,oil compositions,temperature and time,pressure,water,minerals and solid organic matter.We compare previous experimental and modelling results and present new field cases.In the following,we evaluate the prevailing estimation methods for the extent of oil cracking,and elucidate other factors that may interfere with the application of these estimation methods.This review will be helpful for further investigations of crude oil cracking and provides a guide for estimation of the cracking extent of crude oils. 展开更多
关键词 Oil cracking Deep reservoir Controlling factor Gas to oil ratio Diamondoid
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A Note on Approximation of Likelihood Ratio Statistic in Exploratory Factor Analysis
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作者 Masanori Ichikawa 《Open Journal of Statistics》 2015年第6期600-603,共4页
In normal theory exploratory factor analysis, likelihood ratio (LR) statistic plays an important role in evaluating the goodness-of-fit of the model. In this paper, we derive an approximation of the LR statistic. The ... In normal theory exploratory factor analysis, likelihood ratio (LR) statistic plays an important role in evaluating the goodness-of-fit of the model. In this paper, we derive an approximation of the LR statistic. The approximation is then used to show explicitly that the expectation of the LR statistic agrees with the degrees of freedom of the asymptotic chi-square distribution. 展开更多
关键词 factor Analysis LIKELIHOOD ratio Statistic MAXIMUM LIKELIHOOD Estimation
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Factors Affecting the Relation of Fracture Toughness V_(GC) with Critical Void Growth Ratio R_C/R_O
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作者 Li ZHOU(Department of Civil Engineering, Wuyi University,Jiangmen 529020, China) 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 1998年第6期574-576,共3页
The relationship between fracture toughness VGC and critical void growth RC/RO was studied for ten kinds of Steel. The macroscopic fracture toughness VGC was determined by using notched tensile specimens. and the micr... The relationship between fracture toughness VGC and critical void growth RC/RO was studied for ten kinds of Steel. The macroscopic fracture toughness VGC was determined by using notched tensile specimens. and the microscopic parameters of critical void growth ratio RC/RO were quantitatively measured under SEM. Then, the coefhcient C in the relation VGC = C In(RC/RO) proposed in author's past work was specifically explored. The correlation of C with tensile proderty parameter φ=σyδ/(Eφn) was presented for the Steel investigated, and the effects of low temperature on C were also discussed. Results show that the coefficient C is linearly related to the parameter and insensitive to low temperature. 展开更多
关键词 GC with Critical Void Growth ratio R_C/R_O factors Affecting the Relation of Fracture Toughness V
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Inelastic displacement ratio of low-to mid-rise BRBFs designed under variable levels of seismicity
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作者 Hamdy Abou-Elfath Mostafa Ramadan 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2023年第3期763-775,共13页
Buckling-restrained braces(BRBs)have shown their capability to provide building structures with stiffness,strength,and ductility.Estimating the seismic drifts of buckling-restrained braced frames(BRBFs)is an important... Buckling-restrained braces(BRBs)have shown their capability to provide building structures with stiffness,strength,and ductility.Estimating the seismic drifts of buckling-restrained braced frames(BRBFs)is an important design step to control structural and non-structural damage.In current practice of seismic design,the estimation of seismic drifts of BRBFs is performed by using empirical calculations that are independent upon either the type of the structural system or the design level of seismicity.In these empirical calculations,the seismic drifts are estimated by amplifying the reduced elastic drifts obtained under design lateral loading with a displacement amplification factor(DAF).The value of DAF is considered equal to the product of the response modification factor R and the inelastic displacement ratioρ.The goal of the current research is to assess the value ofρfor low-to mid-rise BRBFs designed under low and high levels of seismicity.This goal has been achieved by conducting a series of elastic and inelastic time-history analyses pertaining to an ensemble of earthquake records on 3-,6-and 9-story BRBFs.The results indicate that theρ-ratio increases with an increase in design seismic intensity and an increase in experienced inelasticity.The range ofρfor low seismicity designs ranges from 0.63 to 0.9,while for high seismicity designs this range stretches from 0.83 to 1.29.It has been found that the consideration of a generalρ-ratio of 1.0 is a reasonable estimation for the design of the BRBFs considered in this study. 展开更多
关键词 displacement amplification factor inelastic displacement ratio SEISMICITY buckling-restrained brace seismic drift seismic design
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Factors Affecting the Ratio of Service Industry in GDP: A Comparative Analysis of China, Japan, and South Korea
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作者 胡翠 许召元 《China Economist》 2012年第4期105-116,共12页
Based on the input-output model and using a demand side approach, this paper surveys how factors such as consumption, investment, net export, intermediate input and price affect the ratio of China's service industry ... Based on the input-output model and using a demand side approach, this paper surveys how factors such as consumption, investment, net export, intermediate input and price affect the ratio of China's service industry as compared with Japan and South Korea. An analysis of China's data indicates that price and residential consumption structure are key contributing factors to the rising ratio of the service industry. Conversely, intermediate input and government consumption are factors that lead to a decrease in the ratio of the service industry. An analysis of Japan and South Korea shows that price and residential consumption structures were linked to the rises in their service industry. This paper concludes that the ratio of China's service industry to gross domestic product (GDP) will continue to rise over the 12th Five-Year Plan period (2011-2015) and beyond. 展开更多
关键词 input and output service industry ratio factor
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Evolution and Risk Factors of Maternal Mortality in Cameroon: A Case Control Study
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作者 Boten Merlin Mandeng Nadia +8 位作者 Achuo Ascensius Mforteh Ngo Dingom Madye Dissack Delon Fanny Tameh Theodore Mbi Kobenge Fidelia Takang William Dobgima Pisoh Walter Ndjene Constance Essome Henri 《Open Journal of Obstetrics and Gynecology》 2023年第7期1259-1277,共19页
Background: Maternal mortality is still high in sub-Saharan Africa, especially in Cameroon where more efforts to reduce maternal mortality and provide universal access to reproductive health should be made. This study... Background: Maternal mortality is still high in sub-Saharan Africa, especially in Cameroon where more efforts to reduce maternal mortality and provide universal access to reproductive health should be made. This study aims to see the evolution of maternal mortality and identify associated risk factors in Laquintinie hospital in Cameroon. Methods: A manual review of records for 166 maternal deaths (cases) and 322 controls was undertaken using a standard audit form. The sample included pregnant women aged 16 - 46 years admitted at the maternity of Laquintinie Hospital in Douala, Cameroon from January 2017 to December 2022. Software SSPS 3 and Logistic regression analysis were used to analyze data. Results: One hundred and sixty-six (166) maternal deaths were identified during the study period for 14,114 live births, representing a maternal mortality ratio of 1176/100,000 live births. Factors significantly associated with maternal mortality included: young age (15 - 24 years) (aOR 0.11, 95% CI 0.00 - 0.76, p = 0.037), Alcohol intake (aOR 22.79, 95% CI 1.04 - 501.3, p = 0.047), Abortion or ectopic pregnancy (aOR 61.53, 95% CI 1.29 - 2927.3, p = 0.037), having no antenatal visits (aOR 388.3 95% CI 5.6 - 2675.9, p = 0.006), being admitted with hemorrhage (aOR 343.7, 95% CI 16.2 - 7276.0, p ,713.0, 95% CI 128.2 - 5,989,223.3, p CI 0.00 - 0.18, p = 0.016). Conclusion: Despite slight decrease in maternal mortality, early diagnosis of pregnancy and good Antenatal care associated with maternal health education are important factors for reducing maternal mortality. Young women were the most affected. Singles, alcoholics, women with a no or only primary education level, and referred women represented the majority of deceased cases. 展开更多
关键词 Maternal Mortality ratio Live Births Risk factors
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Speech Separation Methodology for Hearing Aid
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作者 Joseph Sathiadhas Esra Y.Sukhi 《Computer Systems Science & Engineering》 SCIE EI 2023年第2期1659-1678,共20页
In the design of hearing aids(HA),the real-time speech-enhancement is done.The digital hearing aids should provide high signal-to-noise ratio,gain improvement and should eliminate feedback.In generic hearing aids the ... In the design of hearing aids(HA),the real-time speech-enhancement is done.The digital hearing aids should provide high signal-to-noise ratio,gain improvement and should eliminate feedback.In generic hearing aids the perfor-mance towards different frequencies varies and non uniform.Existing noise can-cellation and speech separation methods drops the voice magnitude under the noise environment.The performance of the HA for frequency response is non uni-form.Existing noise suppression methods reduce the required signal strength also.So,the performance of uniform sub band analysis is poor when hearing aid is con-cern.In this paper,a speech separation method using Non-negative Matrix Fac-torization(NMF)algorithm is proposed for wavelet decomposition.The Proposed non-uniformfilter-bank was validated by parameters like band power,Signal-to-noise ratio(SNR),Mean Square Error(MSE),Signal to Noise and Dis-tortion Ratio(SINAD),Spurious-free dynamic range(SFDR),error and time.The speech recordings before and after separation was evaluated for quality using objective speech quality measures International Telecommunication Union-Telecommunication standard ITU-T P.862. 展开更多
关键词 Speech separation waveletfilter independent component analysis(ICA) non-negative matrix factorization(NMF) fejer-korovkin(FK) signal-to-noise ratio(SNR)
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Stability evaluation method of large cross-section tunnel considering modification of thickness-span ratio in mechanized operation
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作者 Junru Zhang Yumeng Liu Bo Yan 《Railway Sciences》 2023年第2期197-210,共14页
Purpose-This study aims to research the large cross-section tunnel stability evaluation method corrected after considering the thickness-span ratio.Design/methodology/approach-First,taking the Liuyuan Tunnel of Huangg... Purpose-This study aims to research the large cross-section tunnel stability evaluation method corrected after considering the thickness-span ratio.Design/methodology/approach-First,taking the Liuyuan Tunnel of Huanggang-Huangmei High-Speed Railway as an example and taking deflection of the third principal stress of the surrounding rock at a vault after tunnel excavation as the criterion,the critical buried depth of the large section tunnel was determined.Then,the strength reduction method was employed to calculate the tunnel safety factor under different rock classes and thickness-span ratios,and mathematical statistics was conducted to identify the relationships of the tunnel safety factor with the thickness-span ratio and the basic quality(BQ)index of the rock for different rock classes.Finally,the influences of thickness-span ratio,groundwater,initial stress of rock and structural attitude factors were considered to obtain the corrected BQ,based on which the stability of a large cross-section tunnel with a depth of more than 100 m during mechanized operation was analyzed.This evaluation method was then applied to Liuyuan Tunnel and Cimushan No.2 Tunnel of Chongqing Urban Expressway for verification.Findings-This study shows that under different rock classes,the tunnel safety factor is a strict power function of the thickness-span ratio,while a linear function of the BQ to some extent.It is more suitable to use the corrected BQ as a quantitative index to evaluate tunnel stability according to the actual conditions of the site.Originality/value-The existing industry standards do not consider the influence of buried depth and span in the evaluation of tunnel stability.The stability evaluation method of large section tunnel considering the correction of overburden span ratio proposed in this paper achieves higher accuracy for the stability evaluation of surrounding rock in a full or large-section mechanized excavation of double line high-speed railway tunnels. 展开更多
关键词 Large cross-section tunnel Mechanized operation Tunnel stability Thickness-span ratio Basic quality index of rock Safety factor DEPTH SPAN
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数据中心变压器K-factor工程计算方法简析
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作者 高晓明 王谋锐 《建筑电气》 2023年第8期46-52,共7页
由K-factor的定义推导其计算公式,并介绍K-factor工程计算方法——采用分类叠加方法对谐波进行简化计算。结合数据中心工程实例给出计算结果并对其进行分析,提出相关注意点,并在此基础之上提出降低数据中心谐波对变压器影响的措施和建议。
关键词 变压器 K-factor 计算方法 谐波电流 谐波电流含有率 谐波源分类 数据中心 叠加计算
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应激性血糖升高比值联合糖化血红蛋白水平对老年急性缺血性脑卒中病人静脉溶栓后出血转化的预测价值 被引量:1
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作者 吴旭明 柯先金 +1 位作者 孙波 孙振杰 《实用老年医学》 CAS 2024年第1期54-58,共5页
目的 探讨应激性血糖升高比值(SHR)联合HbA1c对老年急性缺血性脑卒中(AIS)病人静脉溶栓后出血转化(HT)的预测价值。方法 纳入2018年6月至2020年12月连云港市第一人民医院和江苏大学附属医院接受重组组织型纤溶酶原激活剂(rt-PA)静脉溶栓... 目的 探讨应激性血糖升高比值(SHR)联合HbA1c对老年急性缺血性脑卒中(AIS)病人静脉溶栓后出血转化(HT)的预测价值。方法 纳入2018年6月至2020年12月连云港市第一人民医院和江苏大学附属医院接受重组组织型纤溶酶原激活剂(rt-PA)静脉溶栓AIS老年住院病人共234例,依据急性期内复查CT或MRI结果,将病人分为HT组(n=50)和非HT组(n=184)。收集并比较2组病人临床基线资料。采用多因素Logistic回归分析老年AIS病人rt-PA静脉溶栓后HT的危险因素,应用ROC曲线分析SHR、HbA1c及二者联合预测老年AIS病人rt-PA后HT的价值。结果 2组年龄、溶栓前NIHSS评分、FPG、HbA1c水平,房颤、TOAST分型和梗死大面积比例差异均有统计学意义(P<0.05或P<0.01)。多因素Logistic回归分析结果表明:高水平SHR(OR=39.443,95%CI:1.847~842.343)、HbA1c(OR=1.777,95%CI:1.091~2.859)以及大面积梗死(OR=3.093,95%CI:1.359~7.036)是老年AIS病人rt-PA静脉溶栓后HT的独立危险因素。HbA1c、SHR及二者联合预测老年AIS病人rt-PA静脉溶栓后HT风险的AUC分别为:0.631(95%CI:0.541~0.721)、0.656(95%CI:0.654~0.748)、0.741(95%CI:0.665~0.816)。HbA1c联合SHR预测的AUC显著大于两指标单独预测,差异有统计学意义(P均<0.05)。结论 高水平SHR和HbA1c是老年AIS病人rt-PA静脉溶栓后HT的独立危险因素,两者联合可更好地预测老年AIS病人rt-PA静脉溶栓后HT风险。 展开更多
关键词 急性缺血性脑卒中 出血转化 应激性血糖升高比值 糖化血红蛋白 危险因素
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