The separation-of-variable(SOV)methods,such as the improved SOV method,the variational SOV method,and the extended SOV method,have been proposed by the present authors and coworkers to obtain the closed-form analytica...The separation-of-variable(SOV)methods,such as the improved SOV method,the variational SOV method,and the extended SOV method,have been proposed by the present authors and coworkers to obtain the closed-form analytical solutions for free vibration and eigenbuckling of rectangular plates and circular cylindrical shells.By taking the free vibration of rectangular thin plates as an example,this work presents the theoretical framework of the SOV methods in an instructive way,and the bisection–based solution procedures for a group of nonlinear eigenvalue equations.Besides,the explicit equations of nodal lines of the SOV methods are presented,and the relations of nodal line patterns and frequency orders are investigated.It is concluded that the highly accurate SOV methods have the same accuracy for all frequencies,the mode shapes about repeated frequencies can also be precisely captured,and the SOV methods do not have the problem of missing roots as well.展开更多
The central trinomial coefficient T_(n)denotes the coefficient of x^(n)in the expansion of(1+x+x^(2))^(n).We prove a congruence related to the sums of the central trinomial coefficient and the central binomial coeffic...The central trinomial coefficient T_(n)denotes the coefficient of x^(n)in the expansion of(1+x+x^(2))^(n).We prove a congruence related to the sums of the central trinomial coefficient and the central binomial coefficient,which was conjectured by Z.-W.Sun.展开更多
Objectives: To determine the level of adversity quotient and its associations with rumination, optimism, and authoritative parenting style in junior high school students. Adversity quotient is the adaptation ability t...Objectives: To determine the level of adversity quotient and its associations with rumination, optimism, and authoritative parenting style in junior high school students. Adversity quotient is the adaptation ability to overcome problems and obstacles with a positive attitude. Early adolescence, as a critical stage of life, needs to cultivate adversity quotient. However, adversity quotient and its influencing factors in adolescents have not been fully understood. Methods: A total of 129 students from 3 junior high schools (grade 7-9) in Chon Buri province, Thailand, were randomly recruited to participate in this correlational research study. They completed 5 questionnaires including the demographic form, adversity quotient assessment, authoritative parenting style, optimism, and rumination. Descriptive statistics and Pearson’s correlation coefficient were used for data analysis. Results: Adversity quotient was at a moderate level with a mean of 138.78 (standard deviation [SD] = 21.25). Adversity quotient was significantly, positively correlated with authoritative parenting at the highest level (r = 0.60), followed by optimism at a moderate level (r = 0.38), and rumination at a low level (r = 0.25, P < 0.01). Conclusions: All parties responsible for early adolescents’ development should enhance the adversity quotient to a higher level through campaigns promoting authoritative parenting and optimism. An unexpected positive correlation between adversity quotient and rumination warrants cautious interpretation and more studies.展开更多
Personal care products(PCPs)are a class of emerging pollutants that have attracted public concern owing to their harmful effects on humans and the environment.Biomonitoring data is valuable for insight the levels of P...Personal care products(PCPs)are a class of emerging pollutants that have attracted public concern owing to their harmful effects on humans and the environment.Biomonitoring data is valuable for insight the levels of PCPs in the human body and can be crucial for identifying potential health hazards.To gain a better understanding of timely exposure profiles and health risk of reproductive-age population to PCPs,we determined six parabens,six benzophenone-type ultraviolet filters,and three disinfectants in 256 urine samples collected from young adults aged 18-44 years in Beijing,China.The urinary levels of benzophenone-3(BP-3)and 4-hydroxybenzophenone(4-OHBP)were significantly higher in summer compared to winter,suggesting these compounds have different seasonal usage patterns.Moreover,the total concentration of 15 PCPs in female was 430 ng/mL,approximately two times higher than that in male.P-chloro-m-xylenol(PCMX),as a new type of antibacterial agent,has the greatest level among all target analytes,indicating the increasingly use of this antibacterial alternative recently.Five potential influencing factors that lead to the elevated exposure level of PCPs were identified.Over 19%of the target population had a high hazard index value(greater than 1)which was attributed to exposure to propyl paraben(PrP),benzophenone-1(BP-1),BP-3 and PCMX,indicating that PCPs may pose a relatively high exposure risk at environmental levels that should be a cause for concern.展开更多
Background There have been numerous intervention studies focusing on the development of preterm infants,but there has been limited investigation into the home environment as a determinant of developmental outcomes in ...Background There have been numerous intervention studies focusing on the development of preterm infants,but there has been limited investigation into the home environment as a determinant of developmental outcomes in preterm infants.The aspects and extent to which the home environment affects the early(18 months corrected age)neuropsychological development of preterm infants are still unclear.Aims This study aimed to analyse the effect of the home environment on the neuropsychiatric development of preterm infants at 18 months corrected age after discharge from the neonatal intensive care unit(NICU).It also sought to provide a basis for promoting neuropsychiatric development among preterm infants by improving the home environment.Methods In this retrospective cross-sectional study,275 preterm infants born between January 2019 and January 2022 were followed up for systematic management after discharge from the NICU at Shanghai Children's Hospital.The Home Nurture Environment Questionnaire was used to assess the home environment of the infants and analyse its impact on the developmental quotient(evaluated by the Gesell Developmental Scale)and the rate of developmental delays at 18 months corrected age.Results A total of 41.454%of the infants were extremely preterm.The developmental quotient scores at 18 months corrected age were in the middle of the scale.The language domain had the highest rate of developmental delay(46.182%),followed by the adaptive domain(37.091%).Multiple logistic regression analyses showed that compared with infants in supportive home environments,infants with moderate/unsupportive home environments had significantly elevated risks of development delay:2.162-fold for global(odds ratio(OR)2.162,95% confidence interval(Cl)1.274 to 3.665,p=0.004),2.193-fold for fine motor(OR 2.193,95%CI 1.161 to 4.140,p=0.016),2.249-fold for language(0R 2.249,95%CI 1.336 to 3.786,p=0.002)and 2.042-fold for personal-social(OR 2.042,95%CI 1.149 to 3.628,p=0.015).Conclusions A supportive home environment is a crucial protective factor for the neuropsychological development of preterm infants.It is associated with higher developmental quotient scores and protects against neuropsychiatric delays.Incorporating evaluation and continuous improvement of the home environment into the management framework for preterm infants to promote optimal neurodevelopment is essential.展开更多
Rice cropping method is primarily decided by soil moisture regime.System of rice intensification(SRI)and direct-seeded aerobic rice are two primary modifications of traditional wetland rice.Understanding rice rhizosph...Rice cropping method is primarily decided by soil moisture regime.System of rice intensification(SRI)and direct-seeded aerobic rice are two primary modifications of traditional wetland rice.Understanding rice rhizosphere microbiome and functioning as influenced by these cropping methods is essential for sustaining rice productivity.The objective of this study was to assess the impact of three different rice cropping methods(wetland rice,SRI,and aerobic rice)on the biochemical properties and bacterial communities within the rice rhizosphere across three key rice growth stages:tillering,flowering,and maturity.Soil organic carbon(SOC),microbial biomass carbon(MBC),dehydrogenase activity,substrate-induced respiration(SIR),and metabolic quotient(MQ)were assessed along with high-throughput 16S rRNA sequencing of rice rhizosphere soils.The rice rhizosphere soil registered the highest SOC,MBC,and dehydrogenase activity in SRI followed by wetland rice and then aerobic rice.Cropping method had a minimal impact on SIR and MQ.Along with cropping method,growth stage also significantly altered these biological attributes of rice rhizosphere.The trends of the highest SOC content and dehydrogenase activity at the flowering stage and the highest MBC content and SIR at the tillering stage of rice were observed in all three rice cropping methods.The analysis of bacterial communities,based on 16S rRNA gene sequencing,revealed that both cropping method and growth stage significantly impacted the composition of rhizosphere microbiomes.However,the influence of cropping method was less pronounced compared to growth stage.Cropping method caused notable shifts in the abundances of Proteobacteria,Bacteroidetes,and Chloroflexi,while growth stage affected the abundances of Proteobacteria,Actinobacteria,Cyanobacteria,Firmicutes,Chloroflexi,and Bacteroidetes.Based on these results,the SRI method led to higher diversification to the rhizosphere bacteriobiota,as well as greater incorporation of carbon into the soil and increased dehydrogenase activity compared to wetland rice and aerobic rice.This study deepens our understanding of how different cropping methods influence plant-microbe interaction and the implications for overall rice productivity and soil health.展开更多
In this paper, we derive the a priori estimates for a class of more general (k, l)-Hessian quotient type equations involving u and Du on the right hand function. As an application we prove the Liouville theorem depend...In this paper, we derive the a priori estimates for a class of more general (k, l)-Hessian quotient type equations involving u and Du on the right hand function. As an application we prove the Liouville theorem depending on Pogorelov type estimates. On the other hand, we obtain the existence and uniqueness of the k-admissible solution for these general equations with the Neumann boundary condition, based on some growth conditions for the right hand function.展开更多
A presentation of hyperbolic unitary group is an important part in the unitary group. The group KG 2,n (R) plays an elementary role in presentation of unitary group. It is proved that KG 2,n(R)=1 for n≥2 over a...A presentation of hyperbolic unitary group is an important part in the unitary group. The group KG 2,n (R) plays an elementary role in presentation of unitary group. It is proved that KG 2,n(R)=1 for n≥2 over a ring R with division ring of quotients, using a new method, and a presentation of GE n(R) is given.展开更多
The Causal relation and whole-part relation are the two fundamen-tal relations in economics.In this paper,on the basis of economic prob-lems analysis in practioce,some causal relation structures of economic sys-tems a...The Causal relation and whole-part relation are the two fundamen-tal relations in economics.In this paper,on the basis of economic prob-lems analysis in practioce,some causal relation structures of economic sys-tems and fundamental rules for operations research are,at first,prop-osed.And then,a quotienting(simplifying)analysis approach of eco-nomic causal relations is presented and discussed in detail.At last,animprovement framework of system dynamics is proposed based on theviewpoint of generalized causal relations analysis.展开更多
采用原子吸收光谱法测定北京市10个郊区县25种蔬菜154个样品中Cr,Cd,Cu和Zn重金属含量,并与中国食品中污染物限量标准进行比较;运用目标危害系数方法 (the target hazard quotient,THQ)评价当地居民摄食蔬菜导致的健康风险,比较成人和...采用原子吸收光谱法测定北京市10个郊区县25种蔬菜154个样品中Cr,Cd,Cu和Zn重金属含量,并与中国食品中污染物限量标准进行比较;运用目标危害系数方法 (the target hazard quotient,THQ)评价当地居民摄食蔬菜导致的健康风险,比较成人和儿童居民THQ值大小。结果显示,蔬菜中Cr,Cd,Cu和Zn的平均含量分别是0.210,0.0123,1.034,3.343mg/kg,均未超过中国食品中污染物限量标准,但根茎类蔬菜Cr含量均值超过限量标准,在根菜类中其超标率为41.2%;部分生菜样品的Cr含量有超标,在叶菜类蔬菜中的超标率为2.22%;蔬菜重金属综合污染指数的评价结果属于优良,在安全级别之列,其中Cr为轻污染,Cd,Cu和Zn为优良。成人摄食蔬菜导致的Cr,Cd,Cu和Zn的THQ值分别为1.134,0.199,0.419和0.181,儿童为1.490,0.262,0.550和0.237,两者均存在因摄食蔬菜导致的Cr潜在健康风险。成人和儿童重金属复合风险系数分别为1.932和2.539,复合风险主要由Cr引起。各单一重金属的复合风险对成人和对儿童贡献率基本上一致,儿童因为摄取蔬菜而引起的重金属健康风险相对大于成人。展开更多
【问】[461]IQ表示智商,EQ表示情商,其中字母Q的全称是quotient,根据《牛津高阶英汉双解词典》第1221页的解释是:number obtained when one number is divided by another。中文解释是'商',这没有问题,但是字典在'商'...【问】[461]IQ表示智商,EQ表示情商,其中字母Q的全称是quotient,根据《牛津高阶英汉双解词典》第1221页的解释是:number obtained when one number is divided by another。中文解释是'商',这没有问题,但是字典在'商'后面的括号中给出了这样的补充说明:商(除数除以被除数的得数)。请问这样的解释对吗?展开更多
We reviewed organophosphorus pesticide use in Japan between 1982 and 2016 using data from the National Institute of Environmental Studies. Organophosphorus pesticide concentrations in river water throughout Japan were...We reviewed organophosphorus pesticide use in Japan between 1982 and 2016 using data from the National Institute of Environmental Studies. Organophosphorus pesticide concentrations in river water throughout Japan were taken from the literature, and risk assessments were performed for some organophosphorus pesticides based on risk quotients and hazard quotients. Assessments were performed for 20 common pesticides,including insecticides, fungicides, and herbicides. The amounts used decreased in the order: insecticides > herbicides > fungicides. Organophosphorus insecticide and fungicide use have decreased over the last four decades, but organophosphorus herbicide use has increased. During this period, annual organophosphorus pesticide use was the highest for chlorpyrifos(105,263 tons/year) and the lowest for glyphosate-sodium(8 tons/year). The ecotoxicological risk assessment indicated that diazinon and fenitrothion posed strong risks to the Japanese aquatic environment, and chlorpyrifos and malathion have moderate risks. None of the pesticides that were assessed posed significant risks to humans.Continued use of organophosphorus pesticides in Japan may cause strong risks to aquatic environments. These risks should be reassessed periodically.展开更多
A presentation of hyperbolic unitary group is an important part in the unitary group. The group KG 2,n (R) plays an elementary role in presentation of unitary group. It is proved that KG 2,n(R)=1 for n≥2 over a...A presentation of hyperbolic unitary group is an important part in the unitary group. The group KG 2,n (R) plays an elementary role in presentation of unitary group. It is proved that KG 2,n(R)=1 for n≥2 over a ring R with division ring of quotients, using a new method, and a presentation of GE n(R) is given.展开更多
Soil samples were collected from Zhangshi Wastewater Irrigation Area in the suburb of Shenyang City,China,an area with a 30-year irrigation history with heavy metal-containing wastewater.The chemical properties and mi...Soil samples were collected from Zhangshi Wastewater Irrigation Area in the suburb of Shenyang City,China,an area with a 30-year irrigation history with heavy metal-containing wastewater.The chemical properties and microbial characteristics of the soils were examined to evaluate the present situation of heavy metal pollution and to assess the soil microbial characteristics under long-term heavy metal stress.In light of the National Environmental Quality Standards of China,the soil in the test area was heavily polluted by Cd and to a lesser degree by Zn and Cu,even though wastewater irrigation ceased in 1993.Soil metabolic quotient (qCO_2) had a significant positive correlation,while soil microbial quotient (qM) had a negative correlation with content of soil heavy metals.Soil microbial biomass carbon (MBC) had significantly negative correlation with Cd,but soil substrate-induced respiration (SIR),dehydrogenase activity (DHA),cellulase activity, and culturable microbial populations had no persistent correlations with soil heavy metal content.Soil nutrients,except for phosphorous,showed positive effects on soil microbial characteristics,which to a certain degree obscured the adverse effects of soil heavy metals.Soil Cd contributed more to the soil microbial characteristics,but qM and qCO_2 were more sensitive and showed persistent responses to heavy metals stress.It could be concluded that qM and qCO_2 can be used as bioindicators of heavy metal pollution in soils.展开更多
The mechanism of vegetation restoration on degraded karst regions has been a research focus of soil science and ecology for the last decade.In an attempt to preferably interpret the soil microbiological characteristic...The mechanism of vegetation restoration on degraded karst regions has been a research focus of soil science and ecology for the last decade.In an attempt to preferably interpret the soil microbiological characteristic variation associated with vegetation restoration and further to explore the role of soil microbiology in vegetation restoration mechanism of degraded karst regions,we measured microbial biomass C and basal respiration in soils during vegetation restoration in Zhenfeng County of southwestern Guizhou Province,China.The community level physiological profiles(CLPP) of the soil microbial community to were estimated determine if vegetation changes were accompanied by changes in functioning of soil microbial communities.The results showed that soil microbial biomass C and microbial quotient(microbial biomass C/organic C) tended to increase with vegetation restoration,being in the order arboreal community stage > shrubby community stage > herbaceous community stage > bare land stage.Similar trend was found in the change of basal respiration(BR).The metabolic quotient(the ratio of basal respiration to microbial biomass,qCO 2) decreased with vegetation restoration,and remained at a constantly low level in the arboreal community stage.Analyses of the CLPP data indicated that vegetation restoration tended to result in higher average well color development,substrate richness,and functional diversity.Average utilization of specific substrate guilds was highest in the arboreal community stage.Principle component analysis of the CLPP data further indicated that the arboreal community stage was distinctly different from the other three stages.In conclusion,vegetation restoration improved soil microbial biomass C,respiration,and utilization of carbon sources,and decreased qCO 2,thus creating better soil conditions,which in turn could promote the restoration of vegetation on degraded karst regions.展开更多
Successional and seasonal effects on soil microbial and enzymatic properties were studied in Chinese pine （Pinus tabulaeformis） plantations in an age sequence of 3-, 7-, 13-, 21- and 28-year-old in northern Ziwuling...Successional and seasonal effects on soil microbial and enzymatic properties were studied in Chinese pine （Pinus tabulaeformis） plantations in an age sequence of 3-, 7-, 13-, 21- and 28-year-old in northern Ziwuling region in the middle of Loess Plateau, China. The results indicated that plantation age and season affected soil microbial and enzymatic parameters significantly. Soil organic C, total N, microbial biomass C, microbial quotient, basal respiration, dehydrogenase, N-α-benzoyl-L-argininamide （BAA）-protease, urease and β-glucosidase increased quickly and tended to be highest at PF21 （21-year plantation）, thereafter they remained nearly at a constant level, whereas the metabolic quotient （qCO2） showed an initial increase and then decreased gradually. Measures of these soil properties showed significant seasonal fluctuations except for organic C and total N, which were found to be relatively stable throughout the study period, and the seasonal distributions were autumn 〉 spring 〉 summer 〉 winter for microbial biomass C, microbial quotient, dehydrogenase, and β-glucosidase; autumn 〉 summer 〉 spring 〉 winter for BAA-protease and urease; and summer 〉 autumn 〉 spring 〉 winter for basal respiration and qCO2. Significant season x age interaction was observed for biomass C, basal respiration, dehydrogenase and BAA-protease.展开更多
基金supported by the National Natural Science Foundation of China(12172023).
文摘The separation-of-variable(SOV)methods,such as the improved SOV method,the variational SOV method,and the extended SOV method,have been proposed by the present authors and coworkers to obtain the closed-form analytical solutions for free vibration and eigenbuckling of rectangular plates and circular cylindrical shells.By taking the free vibration of rectangular thin plates as an example,this work presents the theoretical framework of the SOV methods in an instructive way,and the bisection–based solution procedures for a group of nonlinear eigenvalue equations.Besides,the explicit equations of nodal lines of the SOV methods are presented,and the relations of nodal line patterns and frequency orders are investigated.It is concluded that the highly accurate SOV methods have the same accuracy for all frequencies,the mode shapes about repeated frequencies can also be precisely captured,and the SOV methods do not have the problem of missing roots as well.
基金National Natural Science Foundation of China(11971222,12071208)Jiangsu Qinglan ProjectProject of Guangzhou Huashang College(2022HSDS27)。
文摘The central trinomial coefficient T_(n)denotes the coefficient of x^(n)in the expansion of(1+x+x^(2))^(n).We prove a congruence related to the sums of the central trinomial coefficient and the central binomial coefficient,which was conjectured by Z.-W.Sun.
基金supported by the Faculty of Nursing Burapha University(No.19/2561).
文摘Objectives: To determine the level of adversity quotient and its associations with rumination, optimism, and authoritative parenting style in junior high school students. Adversity quotient is the adaptation ability to overcome problems and obstacles with a positive attitude. Early adolescence, as a critical stage of life, needs to cultivate adversity quotient. However, adversity quotient and its influencing factors in adolescents have not been fully understood. Methods: A total of 129 students from 3 junior high schools (grade 7-9) in Chon Buri province, Thailand, were randomly recruited to participate in this correlational research study. They completed 5 questionnaires including the demographic form, adversity quotient assessment, authoritative parenting style, optimism, and rumination. Descriptive statistics and Pearson’s correlation coefficient were used for data analysis. Results: Adversity quotient was at a moderate level with a mean of 138.78 (standard deviation [SD] = 21.25). Adversity quotient was significantly, positively correlated with authoritative parenting at the highest level (r = 0.60), followed by optimism at a moderate level (r = 0.38), and rumination at a low level (r = 0.25, P < 0.01). Conclusions: All parties responsible for early adolescents’ development should enhance the adversity quotient to a higher level through campaigns promoting authoritative parenting and optimism. An unexpected positive correlation between adversity quotient and rumination warrants cautious interpretation and more studies.
基金supported by the National Natural Science Foundation of China (No.22106154).
文摘Personal care products(PCPs)are a class of emerging pollutants that have attracted public concern owing to their harmful effects on humans and the environment.Biomonitoring data is valuable for insight the levels of PCPs in the human body and can be crucial for identifying potential health hazards.To gain a better understanding of timely exposure profiles and health risk of reproductive-age population to PCPs,we determined six parabens,six benzophenone-type ultraviolet filters,and three disinfectants in 256 urine samples collected from young adults aged 18-44 years in Beijing,China.The urinary levels of benzophenone-3(BP-3)and 4-hydroxybenzophenone(4-OHBP)were significantly higher in summer compared to winter,suggesting these compounds have different seasonal usage patterns.Moreover,the total concentration of 15 PCPs in female was 430 ng/mL,approximately two times higher than that in male.P-chloro-m-xylenol(PCMX),as a new type of antibacterial agent,has the greatest level among all target analytes,indicating the increasingly use of this antibacterial alternative recently.Five potential influencing factors that lead to the elevated exposure level of PCPs were identified.Over 19%of the target population had a high hazard index value(greater than 1)which was attributed to exposure to propyl paraben(PrP),benzophenone-1(BP-1),BP-3 and PCMX,indicating that PCPs may pose a relatively high exposure risk at environmental levels that should be a cause for concern.
基金funded by Shanghai Municipal Health and Wellness Commission Health Industry Clinical Research Special Project(202140299).
文摘Background There have been numerous intervention studies focusing on the development of preterm infants,but there has been limited investigation into the home environment as a determinant of developmental outcomes in preterm infants.The aspects and extent to which the home environment affects the early(18 months corrected age)neuropsychological development of preterm infants are still unclear.Aims This study aimed to analyse the effect of the home environment on the neuropsychiatric development of preterm infants at 18 months corrected age after discharge from the neonatal intensive care unit(NICU).It also sought to provide a basis for promoting neuropsychiatric development among preterm infants by improving the home environment.Methods In this retrospective cross-sectional study,275 preterm infants born between January 2019 and January 2022 were followed up for systematic management after discharge from the NICU at Shanghai Children's Hospital.The Home Nurture Environment Questionnaire was used to assess the home environment of the infants and analyse its impact on the developmental quotient(evaluated by the Gesell Developmental Scale)and the rate of developmental delays at 18 months corrected age.Results A total of 41.454%of the infants were extremely preterm.The developmental quotient scores at 18 months corrected age were in the middle of the scale.The language domain had the highest rate of developmental delay(46.182%),followed by the adaptive domain(37.091%).Multiple logistic regression analyses showed that compared with infants in supportive home environments,infants with moderate/unsupportive home environments had significantly elevated risks of development delay:2.162-fold for global(odds ratio(OR)2.162,95% confidence interval(Cl)1.274 to 3.665,p=0.004),2.193-fold for fine motor(OR 2.193,95%CI 1.161 to 4.140,p=0.016),2.249-fold for language(0R 2.249,95%CI 1.336 to 3.786,p=0.002)and 2.042-fold for personal-social(OR 2.042,95%CI 1.149 to 3.628,p=0.015).Conclusions A supportive home environment is a crucial protective factor for the neuropsychological development of preterm infants.It is associated with higher developmental quotient scores and protects against neuropsychiatric delays.Incorporating evaluation and continuous improvement of the home environment into the management framework for preterm infants to promote optimal neurodevelopment is essential.
基金support from the Indian Council of Agricultural Research through the All India Network Project(AINP)on Soil Biodiversity and Biofertilizers to conduct this study is acknowledged。
文摘Rice cropping method is primarily decided by soil moisture regime.System of rice intensification(SRI)and direct-seeded aerobic rice are two primary modifications of traditional wetland rice.Understanding rice rhizosphere microbiome and functioning as influenced by these cropping methods is essential for sustaining rice productivity.The objective of this study was to assess the impact of three different rice cropping methods(wetland rice,SRI,and aerobic rice)on the biochemical properties and bacterial communities within the rice rhizosphere across three key rice growth stages:tillering,flowering,and maturity.Soil organic carbon(SOC),microbial biomass carbon(MBC),dehydrogenase activity,substrate-induced respiration(SIR),and metabolic quotient(MQ)were assessed along with high-throughput 16S rRNA sequencing of rice rhizosphere soils.The rice rhizosphere soil registered the highest SOC,MBC,and dehydrogenase activity in SRI followed by wetland rice and then aerobic rice.Cropping method had a minimal impact on SIR and MQ.Along with cropping method,growth stage also significantly altered these biological attributes of rice rhizosphere.The trends of the highest SOC content and dehydrogenase activity at the flowering stage and the highest MBC content and SIR at the tillering stage of rice were observed in all three rice cropping methods.The analysis of bacterial communities,based on 16S rRNA gene sequencing,revealed that both cropping method and growth stage significantly impacted the composition of rhizosphere microbiomes.However,the influence of cropping method was less pronounced compared to growth stage.Cropping method caused notable shifts in the abundances of Proteobacteria,Bacteroidetes,and Chloroflexi,while growth stage affected the abundances of Proteobacteria,Actinobacteria,Cyanobacteria,Firmicutes,Chloroflexi,and Bacteroidetes.Based on these results,the SRI method led to higher diversification to the rhizosphere bacteriobiota,as well as greater incorporation of carbon into the soil and increased dehydrogenase activity compared to wetland rice and aerobic rice.This study deepens our understanding of how different cropping methods influence plant-microbe interaction and the implications for overall rice productivity and soil health.
基金supported by the National Natural Science Foundation of China(No.11971157).
文摘In this paper, we derive the a priori estimates for a class of more general (k, l)-Hessian quotient type equations involving u and Du on the right hand function. As an application we prove the Liouville theorem depending on Pogorelov type estimates. On the other hand, we obtain the existence and uniqueness of the k-admissible solution for these general equations with the Neumann boundary condition, based on some growth conditions for the right hand function.
文摘A presentation of hyperbolic unitary group is an important part in the unitary group. The group KG 2,n (R) plays an elementary role in presentation of unitary group. It is proved that KG 2,n(R)=1 for n≥2 over a ring R with division ring of quotients, using a new method, and a presentation of GE n(R) is given.
基金Supported by Gansu Porvincinl Youth Scicnce Foudation
文摘The Causal relation and whole-part relation are the two fundamen-tal relations in economics.In this paper,on the basis of economic prob-lems analysis in practioce,some causal relation structures of economic sys-tems and fundamental rules for operations research are,at first,prop-osed.And then,a quotienting(simplifying)analysis approach of eco-nomic causal relations is presented and discussed in detail.At last,animprovement framework of system dynamics is proposed based on theviewpoint of generalized causal relations analysis.
文摘采用原子吸收光谱法测定北京市10个郊区县25种蔬菜154个样品中Cr,Cd,Cu和Zn重金属含量,并与中国食品中污染物限量标准进行比较;运用目标危害系数方法 (the target hazard quotient,THQ)评价当地居民摄食蔬菜导致的健康风险,比较成人和儿童居民THQ值大小。结果显示,蔬菜中Cr,Cd,Cu和Zn的平均含量分别是0.210,0.0123,1.034,3.343mg/kg,均未超过中国食品中污染物限量标准,但根茎类蔬菜Cr含量均值超过限量标准,在根菜类中其超标率为41.2%;部分生菜样品的Cr含量有超标,在叶菜类蔬菜中的超标率为2.22%;蔬菜重金属综合污染指数的评价结果属于优良,在安全级别之列,其中Cr为轻污染,Cd,Cu和Zn为优良。成人摄食蔬菜导致的Cr,Cd,Cu和Zn的THQ值分别为1.134,0.199,0.419和0.181,儿童为1.490,0.262,0.550和0.237,两者均存在因摄食蔬菜导致的Cr潜在健康风险。成人和儿童重金属复合风险系数分别为1.932和2.539,复合风险主要由Cr引起。各单一重金属的复合风险对成人和对儿童贡献率基本上一致,儿童因为摄取蔬菜而引起的重金属健康风险相对大于成人。
文摘【问】[461]IQ表示智商,EQ表示情商,其中字母Q的全称是quotient,根据《牛津高阶英汉双解词典》第1221页的解释是:number obtained when one number is divided by another。中文解释是'商',这没有问题,但是字典在'商'后面的括号中给出了这样的补充说明:商(除数除以被除数的得数)。请问这样的解释对吗?
基金The Japan Society for the Promotion of Science(JSPS)supported by JSPS KAKENHI grant number16KT0149,Japan
文摘We reviewed organophosphorus pesticide use in Japan between 1982 and 2016 using data from the National Institute of Environmental Studies. Organophosphorus pesticide concentrations in river water throughout Japan were taken from the literature, and risk assessments were performed for some organophosphorus pesticides based on risk quotients and hazard quotients. Assessments were performed for 20 common pesticides,including insecticides, fungicides, and herbicides. The amounts used decreased in the order: insecticides > herbicides > fungicides. Organophosphorus insecticide and fungicide use have decreased over the last four decades, but organophosphorus herbicide use has increased. During this period, annual organophosphorus pesticide use was the highest for chlorpyrifos(105,263 tons/year) and the lowest for glyphosate-sodium(8 tons/year). The ecotoxicological risk assessment indicated that diazinon and fenitrothion posed strong risks to the Japanese aquatic environment, and chlorpyrifos and malathion have moderate risks. None of the pesticides that were assessed posed significant risks to humans.Continued use of organophosphorus pesticides in Japan may cause strong risks to aquatic environments. These risks should be reassessed periodically.
文摘A presentation of hyperbolic unitary group is an important part in the unitary group. The group KG 2,n (R) plays an elementary role in presentation of unitary group. It is proved that KG 2,n(R)=1 for n≥2 over a ring R with division ring of quotients, using a new method, and a presentation of GE n(R) is given.
基金Project supported by the National Key Basic Research Support Foundation of China (No.2004CB418503).
文摘Soil samples were collected from Zhangshi Wastewater Irrigation Area in the suburb of Shenyang City,China,an area with a 30-year irrigation history with heavy metal-containing wastewater.The chemical properties and microbial characteristics of the soils were examined to evaluate the present situation of heavy metal pollution and to assess the soil microbial characteristics under long-term heavy metal stress.In light of the National Environmental Quality Standards of China,the soil in the test area was heavily polluted by Cd and to a lesser degree by Zn and Cu,even though wastewater irrigation ceased in 1993.Soil metabolic quotient (qCO_2) had a significant positive correlation,while soil microbial quotient (qM) had a negative correlation with content of soil heavy metals.Soil microbial biomass carbon (MBC) had significantly negative correlation with Cd,but soil substrate-induced respiration (SIR),dehydrogenase activity (DHA),cellulase activity, and culturable microbial populations had no persistent correlations with soil heavy metal content.Soil nutrients,except for phosphorous,showed positive effects on soil microbial characteristics,which to a certain degree obscured the adverse effects of soil heavy metals.Soil Cd contributed more to the soil microbial characteristics,but qM and qCO_2 were more sensitive and showed persistent responses to heavy metals stress.It could be concluded that qM and qCO_2 can be used as bioindicators of heavy metal pollution in soils.
基金Supported by the National Basic Research Program (973 Program) of China (No. 2006CB403206)the Key Project in the NationalScience & Technology Pillar Program in the Eleventh Five-year Plan Period of China (Nos. 2006BAC01A09 and 2006BAD03A1006)National Natural Science Foundation of China (No. 30872076)
文摘The mechanism of vegetation restoration on degraded karst regions has been a research focus of soil science and ecology for the last decade.In an attempt to preferably interpret the soil microbiological characteristic variation associated with vegetation restoration and further to explore the role of soil microbiology in vegetation restoration mechanism of degraded karst regions,we measured microbial biomass C and basal respiration in soils during vegetation restoration in Zhenfeng County of southwestern Guizhou Province,China.The community level physiological profiles(CLPP) of the soil microbial community to were estimated determine if vegetation changes were accompanied by changes in functioning of soil microbial communities.The results showed that soil microbial biomass C and microbial quotient(microbial biomass C/organic C) tended to increase with vegetation restoration,being in the order arboreal community stage > shrubby community stage > herbaceous community stage > bare land stage.Similar trend was found in the change of basal respiration(BR).The metabolic quotient(the ratio of basal respiration to microbial biomass,qCO 2) decreased with vegetation restoration,and remained at a constantly low level in the arboreal community stage.Analyses of the CLPP data indicated that vegetation restoration tended to result in higher average well color development,substrate richness,and functional diversity.Average utilization of specific substrate guilds was highest in the arboreal community stage.Principle component analysis of the CLPP data further indicated that the arboreal community stage was distinctly different from the other three stages.In conclusion,vegetation restoration improved soil microbial biomass C,respiration,and utilization of carbon sources,and decreased qCO 2,thus creating better soil conditions,which in turn could promote the restoration of vegetation on degraded karst regions.
基金Supported by the National Natural Science Foundation of China (Nos. 41171154 and 41021091)the National KeyTechnologies R&D Program of China (Nos. 2011BAK12B05 and 2011BAK12B08)+2 种基金the Program for New Century ExcellentTalents in University (No. NECT-09-0449)the Discipline Innovation S&T Program in Higher Learning Institutions(111 Program)the Ministry of Education & the State Administration of Foreign Experts Affairs, China (No. B06026)
文摘Successional and seasonal effects on soil microbial and enzymatic properties were studied in Chinese pine （Pinus tabulaeformis） plantations in an age sequence of 3-, 7-, 13-, 21- and 28-year-old in northern Ziwuling region in the middle of Loess Plateau, China. The results indicated that plantation age and season affected soil microbial and enzymatic parameters significantly. Soil organic C, total N, microbial biomass C, microbial quotient, basal respiration, dehydrogenase, N-α-benzoyl-L-argininamide （BAA）-protease, urease and β-glucosidase increased quickly and tended to be highest at PF21 （21-year plantation）, thereafter they remained nearly at a constant level, whereas the metabolic quotient （qCO2） showed an initial increase and then decreased gradually. Measures of these soil properties showed significant seasonal fluctuations except for organic C and total N, which were found to be relatively stable throughout the study period, and the seasonal distributions were autumn 〉 spring 〉 summer 〉 winter for microbial biomass C, microbial quotient, dehydrogenase, and β-glucosidase; autumn 〉 summer 〉 spring 〉 winter for BAA-protease and urease; and summer 〉 autumn 〉 spring 〉 winter for basal respiration and qCO2. Significant season x age interaction was observed for biomass C, basal respiration, dehydrogenase and BAA-protease.
