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Segmental Duplications Are Common in Rice Genome 被引量:1
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作者 王石平 刘克德 张启发 《Acta Botanica Sinica》 CSCD 2000年第11期1150-1155,共6页
Segmental duplications on rice (Oryza sativa L.) chromosomes 8, 9, 11, and 12 were studied by examining the distributions of sequences resolved by 13 probes detecting multiple copies of DNA sequences. Four of the hyb... Segmental duplications on rice (Oryza sativa L.) chromosomes 8, 9, 11, and 12 were studied by examining the distributions of sequences resolved by 13 probes detecting multiple copies of DNA sequences. Four of the hybridization bands detected by a repetitive sequence probe, rTRS, were mapped to the ends of all the four chromosomes. Two or three of the bands detected by each of the other 12 probes were also mapped to different chromosomes. The bands detected by the same probe usually occurred in similar locations of different chromosomes. Loci detected by different DNA probes were often similarly arranged on different chromosomes. Chromosomes 8 and 9 showed colinearity of marker loci arrangement indicating a possible common origin. A segment on chromosome 9 was also very similar to the previously reported duplicated fragments on the ends of chromosomes 11 and 12 which were also detected in this study, indicating a likely common origin. Moreover, the various degrees of distributional similarity of the segments suggest a complex relationship among the chromosomes in the evolution of the rice genome. These results support the proposition that chromosome duplication and diversification may be a mechanism for the origin and evolution of the chromosomes in the rice genome. 展开更多
关键词 chromosomal duplication repetitive sequence molecular mapping EVOLUTION r
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市场化改革与我国失业保险体系的建立 被引量:1
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作者 毛简 《江南社会学院学报》 2000年第2期26-29,共4页
随着市场化改革的深入进行,失业已经成为一种十分正常的社会现象,而尽快建立和完善我国的失业保险体系则更是今天的改革必须完成的一个重大任务。但是,传统体制的惯性和社会保障体制改革的敏感性却使我们的改革异常艰巨。当然,如果... 随着市场化改革的深入进行,失业已经成为一种十分正常的社会现象,而尽快建立和完善我国的失业保险体系则更是今天的改革必须完成的一个重大任务。但是,传统体制的惯性和社会保障体制改革的敏感性却使我们的改革异常艰巨。当然,如果能够从西方的经验和教训中获得启示,再注意结合我们的国情,相信适合市场经济要求的失业保险体系是能够建立起来的。 展开更多
关键词 市场经济 失业和下岗 失业保险 失业救济 再就业
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Synthesis and Structural Characterization of a Novel Two-Dimensional Heterometallic Coordination Polymer Nd_2Zn_3(EDTA)_3(H_2O)_( 11)·12H_2O 被引量:2
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作者 马宝清 白欧 +1 位作者 易涛 高松 《Journal of Rare Earths》 SCIE EI CAS CSCD 2000年第4期254-257,共4页
A novel two dimensional heterometallic coordination polymer, Nd 2Zn 3(EDTA) 3(H 2O) 11 ·12H 2O (EDTA= ethylenediamine N,N,N',N' tetraacetate) was synthesized and characterized. In the compo... A novel two dimensional heterometallic coordination polymer, Nd 2Zn 3(EDTA) 3(H 2O) 11 ·12H 2O (EDTA= ethylenediamine N,N,N',N' tetraacetate) was synthesized and characterized. In the compound, each Nd 3+ is connected to three Zn 2+ through three carboxylate bridges, while each Zn 2+ has two Nd 3+ neighbors. In this way, a macrocycle involving six neodyium and six zinc ions is produced. The cycles are connected each other to form a two dimensional sheet. These sheets are further linked into a three dimensional network by the water molecules between the layers through rich hydrogen bonding. 展开更多
关键词 rare earths SYNTHESIS structure EDTA zinc comp
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An inverse method for underwater bottom topographyby using SAR imagery 被引量:2
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作者 Jin Yaqiu, Zhang Wei (Center for Wave Scattering and Remote Sensing,Fudan University, Shanghai 200433, China) 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2000年第4期53-62,共10页
Interaction between current and underwater bottom topography leads to roughness of the sea surface, which in turn yields variation of the radar scattering echo. By using the continuity equation and weak hydrodynamic i... Interaction between current and underwater bottom topography leads to roughness of the sea surface, which in turn yields variation of the radar scattering echo. By using the continuity equation and weak hydrodynamic interaction theory in the relaxation time approximation, the spatial variation of the radar scattering cross-section has been proved as proportional to the gradient of current velocity. The current direction is first determined by using two-dimensional (2-D) correlation of spatial variation of backscattering measured by the SAR imagery, as the priori knowledge of the current direction is not available. The inverse algorithm to successively derive 2 - D underwater bottom topography from the SAR imagery is developed. As an application, the SAR SIR- C image over the sea area of Hong Kong, China is studied. 展开更多
关键词 Underwater bottom topography ocean current SAR invers
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A carbon nanoparticle-peptide fluorescent sensor custom-made for simple and sensitive detection of trypsin 被引量:2
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作者 Shanshan Hou Tingting Feng +4 位作者 Na Zhao Jiaxin Zhang Huibin Wang Ning Liang Longshan Zhao 《Journal of Pharmaceutical Analysis》 SCIE CAS CSCD 2020年第5期482-489,共8页
Herein,we report a novel sensor to detect trypsin using a purpose-designed fluorescein-labelled peptide with negatively charged carbon nanoparticles(CNPs)modified by acid oxidation.The fluorescence of the fluorescein-... Herein,we report a novel sensor to detect trypsin using a purpose-designed fluorescein-labelled peptide with negatively charged carbon nanoparticles(CNPs)modified by acid oxidation.The fluorescence of the fluorescein-labelled peptide was quenched by CNPs.The sensor reacted with trypsin to cleave the peptide,resulting in the release of the dye moiety and a substantial increase in fluorescence intensity,which was dose-and time-dependent,and trypsin could be quantified accordingly.Correspondingly,the biosensor has led to the development of a convenient and efficient fluorescent method to measure trypsin activity,with a detection limit of 0.7 mg/mL.The method allows rapid determination of trypsin activity in the normal and acute pancreatitis range,suitable for point-of-care testing.Furthermore,the applicability of the method has been demonstrated by detecting trypsin in spiked urine samples. 展开更多
关键词 Carbon nanoparticles Fluorescence quenching Forster resonance energy transfer(FRET) Fluorescein-labelled peptide Trypsin assay
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Transgenic mice overexpressingγ-aminobutyric acid transporter subtypeⅠ develop obesity 被引量:1
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作者 MA YING HUA JIA HUA HU +5 位作者 XIAO GANG ZHOU RUO WANG ZENG ZHEN TONG MEI JIAN FEI LI HE GUO Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Science, Shanghai 200031, China Shanghai Institute of 《Cell Research》 SCIE CAS CSCD 2000年第4期303-310,共8页
Transgenic mice ubiquitously overexpressing murine γ aminobutyric acid transporter subtype Ⅰ were created. Unexpectedly, these mice markedly exhibited heritable obesity, which features significantly increased body w... Transgenic mice ubiquitously overexpressing murine γ aminobutyric acid transporter subtype Ⅰ were created. Unexpectedly, these mice markedly exhibited heritable obesity, which features significantly increased body weight and fat deposition. Behavioral examination revealed that transgeinc mice have slightly reduced spontaneous locomotive capacity and altered feeding pattern. Tills preliminary finding indicates that the inappropriate level of γ-aminobutyric acid transporters may be directly or indirectly involved in the pathogenic mechanism underlying certain types of obesity. 展开更多
关键词 γ-aminobutyric acid transporter subtype transgenic mouse obesit
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A new method to directly invert the elastic parameters
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作者 张秉铭 张中杰 《Acta Seismologica Sinica(English Edition)》 EI CSCD 2000年第6期698-704,共7页
The aim of seismic data inversion is to assess the physical parameters (including density, elastic parameters and viscous elastic parameters). Defining the best assessing value to be a kind of parameters set, it is si... The aim of seismic data inversion is to assess the physical parameters (including density, elastic parameters and viscous elastic parameters). Defining the best assessing value to be a kind of parameters set, it is simulated that the synthesized seismic records are the most fit to those which were recorded in fields. A new way of directly inversion for elastic parameters has been brought forward in the context. It is suitable to the inversion of elastic parameters in anisotropic media (HTI). It is totally different from those depicted in the previous approaches. In order to classify the strata properties, it utilizes both PP wave and PSV wave to inverse the strata elastic parameters (C11 and C33). It could be called as the inversion of elastic wave equation. 展开更多
关键词 ANISOTROPY strata properties inversi
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NUMERICAL SIMULATIONS OF OCEANIC ELEMENTS IN THE SCS AND ITS NEIGHBORING SEA REGIONS FROM JANUARY TO AUGUST IN 1998
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作者 任雪娟 钱永甫 张耀存 《Journal of Tropical Meteorology》 SCIE 2000年第2期132-140,共9页
Studies on oceanic conditions in the South China Sea (SCS) and adjacent waters are helpful for thorough understanding of summer monsoons in East Asia. To have a 3-dimensional picture of how the oceanic currents vary, ... Studies on oceanic conditions in the South China Sea (SCS) and adjacent waters are helpful for thorough understanding of summer monsoons in East Asia. To have a 3-dimensional picture of how the oceanic currents vary, the oceanic elements in the South China Sea (SCS) and its neighboring sea regions in January ~ August 1998 have been simulated by using the improved Princeton University Ocean Model (POM) in this paper. The main results are in good agreement with that of ocean investigations and other simulations. The results show that the SCS branch of the Kuroshio Current is an important part in the north SCS from January to August; the SCS warm current is reproduced clearly in all months except in winter; there always exists a large-scale anti-cyclonic vortex on the right of the Kuroshio Current from January to August. In the model domain, the surface currents of the SCS have the closest relations with the monsoon with an apparent seasonal variation. In addition, the developing characteristics of the SST in the SCS and its neighboring sea regions before and after the summer monsoon onset are also well simulated by the improved POM. Those are the foundation for developing a coupled regional ocean-atmospheric model system. 展开更多
关键词 regional OCEAN model OCEAN current SUMMER mons
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Clinical Applications of Serum Anti-Mullerian Hormone€Measurements in Both Males and Females:An Update 被引量:10
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作者 Huiyu Xu Mengqian Zhang +4 位作者 Hongxian Zhang Kannan Alpadi Lina Wang Rong Li Jie Qiao 《The Innovation》 2021年第1期63-73,共11页
Infertility is one of the most common non-communicable diseases,affecting both men and women equally.Ovarian reserve,the number of primordial follicles in the ovaries is believed to be the most important determinants ... Infertility is one of the most common non-communicable diseases,affecting both men and women equally.Ovarian reserve,the number of primordial follicles in the ovaries is believed to be the most important determinants for female fertility.Anti-Mullerian hormone(AMH)secreted from granulosa cells of growing follicles is recognized as the most important biomarker for ovarian reserve.Ovarian reserve models have been developed using AMH and other hormonal indicators,thus childbearing plans and reproductive choices could be arranged by women.In assisted reproductive technology cycles,measurement of AMH helps to predict ovarian response and guide recombinant follicle-stimulating hormone dosing in women.Serum AMH level is increasingly being recognized as a potential surrogate marker for polycystic ovarian morphology,one of the criteria for diagnosis of polycystic ovarian syndrome.AMH is also secreted by Sertoli cells of testes in men,and AMH measurements in the prediction of surgical sperm recovery rate in men have also been investigated.AMH levels are significantly higher in boys than in girls before puberty.Therefore,serum levels of AMH in combination with testosterone is used for the differential diagnosis of disorders of sex development,anorchia,non-obstructive azoospermia,and persistent Mullerian duct syndrome.Recently,serum AMH measurements have also been used in fertility preservation programs in oncofertility,screening for granulosa cell tumors,and prediction of menopause applications.In this review,we will focus on clinical application of AMH in fertility assessments for healthy men and women,as well as for cancer patients. 展开更多
关键词 anti-Mullerian hormone assays assisted reproductivetechnology Sertoli cells Granulosa cells ovarian reserve MENOPAUSE PCOS
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Simulation of 3D fracture propagation under I-II-III mixed-mode loading
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作者 Louis Ngai Yuen Wong Xin Cui 《Rock Mechanics Bulletin》 2023年第4期70-83,共14页
Fracture propagation under mixed-mode loading conditions prevails in many natural geological processes and deep engineering projects,while the corresponding numerical simulation is very challenging in rock mechanics,e... Fracture propagation under mixed-mode loading conditions prevails in many natural geological processes and deep engineering projects,while the corresponding numerical simulation is very challenging in rock mechanics,especially in 3D cases.In most previous studies,the complexity of 3D fracture geometry was over-simplified,and model III loading was often not considered.In this study,we propose to use an efficient stress-based Sch€ollmann criterion combined with Displacement Discontinuity Method(DDM)to model 3D fracture propagation under arbitrary I+II+III mixed-mode loading conditions.A novel curve-smoothing algorithm is developed to smoothen the fracture front during propagation,which significantly enhances the model's ability in dealing with complex 3D fracture geometry.In particular,we adopt two different solution schemes,namely staggered and monolithic,to simulate mode I fracture propagation in the case of hydraulic fracturing.The accuracy,efficiency and convergency of the two solution schemes are compared in detail.Our research findings suggest that the degree of coupling between fracture aperture and fluid pressure in hydraulic fracturing lies somewhere between one-way and two-way,which favors the staggered solution scheme.To further test our new model,we provide three additional numerical examples associated with 3D fracture propagation under various mixed-mode loading conditions.Our model shows excellent performance in efficiently locating the new fracture front and reliably capturing the complex 3D fracture geometry.This study provides a generic algorithm to model high-fidelity 3D fracture propagation without simplifying fracture geometry or loading conditions,making it widely applicable to fracture-propagation-related problems. 展开更多
关键词 3D fracture propagation Mixed-mode loading Schollmann criterion Curve smoothing Hydro-mechanical(HM)coupling
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具有宽频与可控微波吸收性能的石墨烯空心微球的自组装 被引量:4
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作者 曾强 陈平 +1 位作者 于祺 徐东卫 《材料研究学报》 EI CAS CSCD 北大核心 2018年第2期119-126,共8页
用简单高效的两步法制备了一种包覆有四氧化三铁的还原石墨烯空心微球(Air@r GO€Fe_3O_4)。两步法包括油包水乳化技术和高温煅烧技术。Air@r GO€Fe_3O_4空心微球的介电损耗和磁损耗优异,使其具有良好的微波吸收性能。空心微球在石蜡中... 用简单高效的两步法制备了一种包覆有四氧化三铁的还原石墨烯空心微球(Air@r GO€Fe_3O_4)。两步法包括油包水乳化技术和高温煅烧技术。Air@r GO€Fe_3O_4空心微球的介电损耗和磁损耗优异,使其具有良好的微波吸收性能。空心微球在石蜡中的添加量为33.3%、厚度为2.8 mm的微球在10 GHz处有最小反射率,为-52 d B,反射率小于-10 d B的频率范围为7.5~14.7 GHz。调节各成分的配比和样品厚度可控制空心微球的吸波性能。随着四氧化三铁含量的提高,微球的最小反射率的峰值位置向高频移动。Air@r GO€Fe_3O_4空心微球有吸收频率范围宽、吸收强度大以及吸波性能可调控等优点,使其成为具有潜在应用价值的高性能吸波材料。 展开更多
关键词 复合材料 宽频与可控微波吸收性能 自组装 Air@rGOFe3O4空心微球 阻抗匹配
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ABR Flow Control Algorithm in ATM Networks: a Neural Network Approach 被引量:3
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作者 GAOHong DINGWei 《The Journal of China Universities of Posts and Telecommunications》 EI CSCD 2000年第4期40-43,共4页
A Neural Network( NN ) approach to ABR flow control algorithm in ATM networks is proposed. The NN predicts the queue length, its variation and possible cell loss, then regulates the source rate adaptivel... A Neural Network( NN ) approach to ABR flow control algorithm in ATM networks is proposed. The NN predicts the queue length, its variation and possible cell loss, then regulates the source rate adaptively. Therefore, more appropriate value of the explicit rate can be determined in the corresponding field of the RM cells. This approach performs better than the traditional static feedback control. Additionally, the performance of this algorithm under CBR background traffic is discussed, and the simulatino results show that the neural network is also efficient. 展开更多
关键词 ABR flow control ATM NN
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Relationship between the burden of pneumocystis carinii, the inflammatory reaction and lung injury in pneumocystis carinii pneumonia 被引量:2
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作者 瞿介明 容朝晖 +2 位作者 何礼贤 潘珏 陈雪华 《Chinese Medical Journal》 SCIE CAS CSCD 2000年第12期15-18,共4页
To study the relationship between the burden of Pneumocystis carinii (P carinii) and the inflammatory reaction and biochemical markers in bronchoalveolar lavage fluids (BALF)in a rat model of P carinii pn... To study the relationship between the burden of Pneumocystis carinii (P carinii) and the inflammatory reaction and biochemical markers in bronchoalveolar lavage fluids (BALF)in a rat model of P carinii pneumonia (PCP) Methods Clean grade 50 male Sprague Dawley rats were immunosuppressed by a subcutaneous injection of 25mg cortisone acetate twice a week for 8-12 weeks; the PCP model was successfully induced in 14 rats The inflammatory reaction and biochemical markers of the activity of lactate dehydrogenase (LDH), alkaline phosphatase (ALP) and type Ⅳ collagenase (matrix metalloproteinases, MMP 2, MMP 9) as well as the values of total protein (TP) and albumin (ALB) in BALF between the mild burden group of P carinii (involved alveoli <25% per 100 alveoli, Group A) and the moderate to severe burden group (involved alveoli ≥25% per 100 alveoli, Group B) were measured The other six clean grade SD rats served as normal control group (Group C) Results The total white cell count in BALF was higher in Group B [(6 8±1 7)×10 6/L] than in Group A [(3 8±1 2)×10 6/L] ( P <0 01); however, there were no differences in white cell differentiation Assays of biochemical markers showed that ALB in BALF in Group B (0 893±0 469?g/L) was increased in comparison with Group A (0 262±0 169 ?g/L); it was only 0 026±0 021?g/L in Group C The contents of TP and activities of LDH were higher in Group B (TP 1 756±0 706?g/L, LDH 2580±550?U/L) than in Group A (TP 0 784±0 553?g/L, LDH 1410±620?U/L); the values of TP and LDH were 0 063±0 020?g/L and 370±250?U/L respectively in Group C The activity of Type Ⅳ collagenase, including MMP 2 and MMP 9, was higher in Group B than in Group A ( P <0 01) (MMP 2: 1102±169 grey value vs 459±274 grey value; MMP 9: 1218±257 grey value vs 449±225 grey value) There was no activity of Type Ⅳ collagenase in BALF of Group C No statistically significant difference was observed in ALP between the groups B and A Conclusions These results indicate that there is a significant correlation between the burden of P carinii in lung tissues and the inflammatory reaction as well as biochemical markers of the resultant activity of lung injury 展开更多
关键词 burden of pneumocystis carinii inflammatory reaction biochemical markers lung injury bronchoalveolar lavage flu
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Numerical Investigation of Dynamic Effects on Unsteady Flow Measurements Using a Two-Dimensional Probe
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作者 李宇红 《Tsinghua Science and Technology》 SCIE EI CAS 2000年第4期395-399,共5页
WTFZ] The dynamic effects in measurements of unsteady flow when using a probe with quasi-steady calibration curves has been investigated in this paper by numerical simulation of the compressible flow around a fixed t... WTFZ] The dynamic effects in measurements of unsteady flow when using a probe with quasi-steady calibration curves has been investigated in this paper by numerical simulation of the compressible flow around a fixed two-dimensional 3-hole probe. The unsteady velocity and pressure distributions, as well as the hole-pressures, are calculated for high frequency flow variations. The measurement errors caused by the dynamic effects indicate that considerable measurement errors may occur for high frequency flow fluctuation, e.g., 2000Hz, especially, when the flow around the probe head approaches separation. This work shows how numerical simulation can be used to investigate and correct for the dynamic effects.[ 展开更多
关键词 dynamic effect unsteady flow quasi-steady flow measurement err
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Effect of cobalt substitution on structure and magnetic properties of Nd0.4Zr0.6Fe10-xCoxSi2(x =0-3) alloys and their ribbons
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作者 M.Gjoka C.Sarafidis +5 位作者 G.Giannopoulos D.Niarchos G.Hadjipanayis J.A.Tabares G.A.Pérez Alcázar L.E.Zamora 《Journal of Rare Earths》 SCIE EI CAS CSCD 2019年第10期1096-1101,共6页
This study reports the stabilization of the RFe12-type based compounds where part of R and Fe are substituted with Zr and Co and Si, respectively, in order to examine whether these rare-earth-lean materials are suitab... This study reports the stabilization of the RFe12-type based compounds where part of R and Fe are substituted with Zr and Co and Si, respectively, in order to examine whether these rare-earth-lean materials are suitable for applications as permanent magnets. Structural and magnetic characterization of the family of alloys with the general formula Nd0.4 Zr0.6 Fe10-xCoxSi2(x = 0 -3) and their melt-spun ribbons were carried out using X-ray diffraction and M€ossbauer spectroscopy. The ThMn12-type structure is obtained for all samples as the majority phase with a minority a-Fe(CoSi) phase(less than 5 wt%) as it was estimated by XRD for x = 1 and 2. The Curie temperature increases linearly with Co substitution from 561 K for x = 0 to 712 K for x = 3. The saturation magnetization decreases slightly from 130.5(x =1)to 129.1 A·m2/kg(x=3), while the anisotropy field is following the same trend. 展开更多
关键词 Permanent MAGNETS X-ray diffraction Mossbauer spectroscopy Rare-earth-lean MAGNETIC materials MAGNETIC properties MELT-SPUN RIBBONS
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Estimation of the True Cost of Living Index of food consumption for Chinese urban consumers
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作者 Zhiyong Fan Jiayin Song 《Economic and Political Studies》 2018年第4期417-430,共14页
This paper studies the True Cost of Living Index(TCLI)of food consumption for all income groups of urban households in China from 1997 to 2012.Based on the Generalised Fechner-Thurstone direct utility function,this pa... This paper studies the True Cost of Living Index(TCLI)of food consumption for all income groups of urban households in China from 1997 to 2012.Based on the Generalised Fechner-Thurstone direct utility function,this paper estimates the TCLI under variable preference assumptions,and also decomposes the total bias of the traditional Laspeyres Price Index(LPI)estimation of TCLI into substitution bias and preference variation bias.For all income group households,the estimated preference variation bias is found to be quite substantial.According to the finding,when it is necessary to apply the cost of living adjustment clause in any public welfare programmes,the TCLI calculation compatible with preference variation may be more appropriate than the usual Laspeyres Consumer Price Index estimation. 展开更多
关键词 Consumer Price Index preference variation bias Konus cost of living index substitution bias
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