The slope of indifference curve is known as a marginal rate of substitution （MRS）. MRS defining ratio always describes slope of indifferent curve, i.e. MRS matches the module of indifferent curves slope. Utility fun...The slope of indifference curve is known as a marginal rate of substitution （MRS）. MRS defining ratio always describes slope of indifferent curve, i.e. MRS matches the module of indifferent curves slope. Utility function U（Xl,X2） is used to calculate marginal rate of substitution （MRS）, because MRS gives the slope of appropriate indifference curve, it can be interpreted as a norm, in which costumer is ready to substitute good 1 by small amount of good 2. The word ＂marginal＂ in economic means ＂differential＂. Here we have partial differentiation, because in time of calculation of good l＇s marginal utility the amount of good 2 remains the same. We can calculate MRS in two ways using differential and function. In the first case consider change （akl,ak2） during which utility is unchanged. For the second method let the curve of indifference present by x2 （X1） function. The function shows how many of x2 is needed for each unit of xl to stay on this concrete curve of indifference. We obtain two equations for the term of MRS and budget constraint and two xl and x2 variables. To define the optimal choice of x1 and x2 as a function of the price and income, we need to solve those two equations. The problem of maximization can be solved by using differential.展开更多
Thinopyrum intermedium and barley are two close relatives of wheat and carry many genes that are potentially valuable for the improvement of various wheat traits. In this study we created wheat double substitution lin...Thinopyrum intermedium and barley are two close relatives of wheat and carry many genes that are potentially valuable for the improvement of various wheat traits. In this study we created wheat double substitution lines by hybridizing different wheat–Th. intermedium and wheat–barley disomic alien substitution lines, with the aim of using genes in Th. intermedium and barley for wheat breeding and investigating the genetic behavior of alien chromosomes and their wheat homoeologs. As expected, we obtained two types of wheat double substitution lines,2D2Ai#2(2B)2H( A) and 2A2 Ai#2(2B)2H(2D), in which different group 2 wheat chromosomes were replaced by barley chromosome 2 H and Th. intermedium chromosome 2Ai#2. The new materials were characterized using molecular markers, genomic in situ hybridization(GISH), and fluorescent in situ hybridization(FISH). GISH and FISH experiments revealed that the double substitution lines harbor 42 chromosomes including 38 wheat chromosomes, a pair of barley chromosomes, and a pair of Th. intermedium chromosomes. Analysis using specific DNA markers showed that two pairs of wheat homoeologous group 2 chromosomes in the new lines were substituted by a pair of 2H and a pair of 2Ai#2 chromosomes. Chromosome 2H showed a higher transmission rate than 2Ai#2, and both chromosomes were preferentially transmitted between generations via female gametes. Evaluation of botanic and agronomic traits demonstrated that,compared with their parents, the new lines showed similar growth habits and plant type but differences in plant height, flowering date, and self-fertility. Cytological observations using different probes suggested that the double substitution lines showed nearly normal genetic behavior before and during meiosis. The novel substitution lines can potentially be used in wheat meiosis research and breeding programs.展开更多
The decomposition of coarse woody debris(CWD)affects the energy flow and nutrient cycling in forest ecosystems.Previous studies on CWD have focused on the input,decomposition,reserve dynamics,and CWD functions,but coa...The decomposition of coarse woody debris(CWD)affects the energy flow and nutrient cycling in forest ecosystems.Previous studies on CWD have focused on the input,decomposition,reserve dynamics,and CWD functions,but coarse woody debris decomposition is complex and the results from different regions vary considerably.It is not clear which factors affect decay rate(k),especially at different decomposition stages.In this study,a single-exponential decay model was used to analyze the characteristics of CWD decomposition in Larix gmelinii forests over the 33 years following a fire in the Greater Khingan Mountains.The results show that the decay rate of coarse woody debris was positively correlated to decay class.The average decomposition rate was 0.019,and 41 years and 176 years are needed for a 50%and 95%mass loss,respectively.CWD nutrient content,density,and water content could explain the variance in the decay rate(~42%)of the decay factors such as amount of leaching,degree of fragmentation,respiration of the debris,and biotransformation,and varied significantly between different decay classes.Using the space-time substitution method,this study arranged the coarse woody debris of different mortality times to form a 33 year chronosequence which revealed the decomposition process.It was concluded that the decay rate was mainly explained by structural component of the debris and its nitrogen and water contents.This paper quantifies the indicators affecting CWD decay to explain the decomposition process.展开更多
Currently in China, to study the replacement rate of pension reform in public institutions and to find out the key problems, which is of practical significance for the reform of the pension insurance system. In this p...Currently in China, to study the replacement rate of pension reform in public institutions and to find out the key problems, which is of practical significance for the reform of the pension insurance system. In this paper, the impact of pension income and expenditure patterns on the substitution rate is analyzed, and the factors that affect the level of substitution rate are analyzed, and the corresponding policy recommendations are put forward.展开更多
According to the China Statistical Yearbook divided eight consumption expenditure, I set food, clothing, housing and household equipment and services as residents basic living expenses, of China＇ s rural pension repl...According to the China Statistical Yearbook divided eight consumption expenditure, I set food, clothing, housing and household equipment and services as residents basic living expenses, of China＇ s rural pension replacement rate level of demand is calculated. The financial revenue scale autoregressive model predicted 2010-2020, the scale of fiscal revenue, with Pratt ＆ Whitney type total pension should be of basic pension and substitution rate level of demand for pension accounts for fiscal revenue proportion of the international experience of fiscal income of 5% were measured and evaluated. The current basic pension in the short term to improve the life of the rural elderly has an important role, but the long-term need to continue to increase, should optimize the structure of fiscal expenditure.展开更多
The ratio of nonsynonymous substitution rate （Ka） to synonymous substitution rate （Ks） is widely used as an indicator of selective pressure at sequence level among different species, and diverse mutation models ha...The ratio of nonsynonymous substitution rate （Ka） to synonymous substitution rate （Ks） is widely used as an indicator of selective pressure at sequence level among different species, and diverse mutation models have been incorporated into several computing methods. We have previously developed a new γ-MYN method by capturing a key dynamic evolution trait of DNA nucleotide sequences, in consideration of varying mutation rates across sites. We now report a further improvement of NG, LWL, MLWL, LPB, MLPB, and YN methods based on an introduction of gamma distribution to illustrate the variation of raw mutation rate over sites. The novelty comes in two ways： （1） we incorporate an optimal gamma distribution shape parameter a into γ-NG, γ-LWL, γ-MLWL, γ-LPB, γ-MLPB, and γ-YN methods; （2） we investigate how variable substitution rates affect the methods that adopt different models as well as the interplay among four evolutional features with respect to Ka/Ks computations. Our results suggest that variable substitution rates over sites under negative selection exhibit an opposite effect on estimates compared with those under positive selection. We believe that the sensitivity of our new methods has been improved than that of their original methods under diverse conditions and it is advantageous to introduce novel parameters for Ka/Ks computation.展开更多
文摘The slope of indifference curve is known as a marginal rate of substitution （MRS）. MRS defining ratio always describes slope of indifferent curve, i.e. MRS matches the module of indifferent curves slope. Utility function U（Xl,X2） is used to calculate marginal rate of substitution （MRS）, because MRS gives the slope of appropriate indifference curve, it can be interpreted as a norm, in which costumer is ready to substitute good 1 by small amount of good 2. The word ＂marginal＂ in economic means ＂differential＂. Here we have partial differentiation, because in time of calculation of good l＇s marginal utility the amount of good 2 remains the same. We can calculate MRS in two ways using differential and function. In the first case consider change （akl,ak2） during which utility is unchanged. For the second method let the curve of indifference present by x2 （X1） function. The function shows how many of x2 is needed for each unit of xl to stay on this concrete curve of indifference. We obtain two equations for the term of MRS and budget constraint and two xl and x2 variables. To define the optimal choice of x1 and x2 as a function of the price and income, we need to solve those two equations. The problem of maximization can be solved by using differential.
基金financially supported by the National Key Research and Development Program of China(2016YFD0102001 and 2016YFD0102002)the National Natural Science Foundation of China(31771788)the Agricultural Science and Technology Innovation Program(ASTIP)of the Chinese Academy of Agricultural Sciences
文摘Thinopyrum intermedium and barley are two close relatives of wheat and carry many genes that are potentially valuable for the improvement of various wheat traits. In this study we created wheat double substitution lines by hybridizing different wheat–Th. intermedium and wheat–barley disomic alien substitution lines, with the aim of using genes in Th. intermedium and barley for wheat breeding and investigating the genetic behavior of alien chromosomes and their wheat homoeologs. As expected, we obtained two types of wheat double substitution lines,2D2Ai#2(2B)2H( A) and 2A2 Ai#2(2B)2H(2D), in which different group 2 wheat chromosomes were replaced by barley chromosome 2 H and Th. intermedium chromosome 2Ai#2. The new materials were characterized using molecular markers, genomic in situ hybridization(GISH), and fluorescent in situ hybridization(FISH). GISH and FISH experiments revealed that the double substitution lines harbor 42 chromosomes including 38 wheat chromosomes, a pair of barley chromosomes, and a pair of Th. intermedium chromosomes. Analysis using specific DNA markers showed that two pairs of wheat homoeologous group 2 chromosomes in the new lines were substituted by a pair of 2H and a pair of 2Ai#2 chromosomes. Chromosome 2H showed a higher transmission rate than 2Ai#2, and both chromosomes were preferentially transmitted between generations via female gametes. Evaluation of botanic and agronomic traits demonstrated that,compared with their parents, the new lines showed similar growth habits and plant type but differences in plant height, flowering date, and self-fertility. Cytological observations using different probes suggested that the double substitution lines showed nearly normal genetic behavior before and during meiosis. The novel substitution lines can potentially be used in wheat meiosis research and breeding programs.
基金This research was funded by the National Key Research and Development Projects,Grant Number 2018YFE0207800the National Natural Science Foundation of China,Grant Number 41871103.
文摘The decomposition of coarse woody debris(CWD)affects the energy flow and nutrient cycling in forest ecosystems.Previous studies on CWD have focused on the input,decomposition,reserve dynamics,and CWD functions,but coarse woody debris decomposition is complex and the results from different regions vary considerably.It is not clear which factors affect decay rate(k),especially at different decomposition stages.In this study,a single-exponential decay model was used to analyze the characteristics of CWD decomposition in Larix gmelinii forests over the 33 years following a fire in the Greater Khingan Mountains.The results show that the decay rate of coarse woody debris was positively correlated to decay class.The average decomposition rate was 0.019,and 41 years and 176 years are needed for a 50%and 95%mass loss,respectively.CWD nutrient content,density,and water content could explain the variance in the decay rate(~42%)of the decay factors such as amount of leaching,degree of fragmentation,respiration of the debris,and biotransformation,and varied significantly between different decay classes.Using the space-time substitution method,this study arranged the coarse woody debris of different mortality times to form a 33 year chronosequence which revealed the decomposition process.It was concluded that the decay rate was mainly explained by structural component of the debris and its nitrogen and water contents.This paper quantifies the indicators affecting CWD decay to explain the decomposition process.
文摘Currently in China, to study the replacement rate of pension reform in public institutions and to find out the key problems, which is of practical significance for the reform of the pension insurance system. In this paper, the impact of pension income and expenditure patterns on the substitution rate is analyzed, and the factors that affect the level of substitution rate are analyzed, and the corresponding policy recommendations are put forward.
文摘According to the China Statistical Yearbook divided eight consumption expenditure, I set food, clothing, housing and household equipment and services as residents basic living expenses, of China＇ s rural pension replacement rate level of demand is calculated. The financial revenue scale autoregressive model predicted 2010-2020, the scale of fiscal revenue, with Pratt ＆ Whitney type total pension should be of basic pension and substitution rate level of demand for pension accounts for fiscal revenue proportion of the international experience of fiscal income of 5% were measured and evaluated. The current basic pension in the short term to improve the life of the rural elderly has an important role, but the long-term need to continue to increase, should optimize the structure of fiscal expenditure.
基金supported by the National Basic Research Program of China (Grant No. 2006CB910404) awarded to JY
文摘The ratio of nonsynonymous substitution rate （Ka） to synonymous substitution rate （Ks） is widely used as an indicator of selective pressure at sequence level among different species, and diverse mutation models have been incorporated into several computing methods. We have previously developed a new γ-MYN method by capturing a key dynamic evolution trait of DNA nucleotide sequences, in consideration of varying mutation rates across sites. We now report a further improvement of NG, LWL, MLWL, LPB, MLPB, and YN methods based on an introduction of gamma distribution to illustrate the variation of raw mutation rate over sites. The novelty comes in two ways： （1） we incorporate an optimal gamma distribution shape parameter a into γ-NG, γ-LWL, γ-MLWL, γ-LPB, γ-MLPB, and γ-YN methods; （2） we investigate how variable substitution rates affect the methods that adopt different models as well as the interplay among four evolutional features with respect to Ka/Ks computations. Our results suggest that variable substitution rates over sites under negative selection exhibit an opposite effect on estimates compared with those under positive selection. We believe that the sensitivity of our new methods has been improved than that of their original methods under diverse conditions and it is advantageous to introduce novel parameters for Ka/Ks computation.
