期刊文献+
共找到2,529篇文章
< 1 2 127 >
每页显示 20 50 100
Effects of Heavy Metal Stress on the Growth Curves of Two Sepcies of Bacteria 被引量:4
1
作者 李淑英 苏亚丽 +2 位作者 周元清 史云东 别金蓉 《Agricultural Science & Technology》 CAS 2010年第8期149-152,共4页
[Objective] The aim was to study on the effects of heavy metal stress on the growth curves of Escherichia coli and Bacillus subtili. [Method] Using traditional culture method,Escherichia coli and Bacillus subtili were... [Objective] The aim was to study on the effects of heavy metal stress on the growth curves of Escherichia coli and Bacillus subtili. [Method] Using traditional culture method,Escherichia coli and Bacillus subtili were cultured under heavy metal stress including Cu2+,Hg2+,Pb2+,Cd2+ and Cr6+ in different concentrations. Then the growth curves of the bacteria were determined to investigate the effects of exogenous heavy metals on the growth of the two kinds of bacteria. [Result] The proliferation of the two bacteria was inhibited at high concentrations of Hg2+ and Cd2+ respectively,and G+ is more sensitive to them than G-; when the heavy metal concentration was 50 mg/L,the toxicity of the five kinds of heavy metals on the two bacteria was Hg2+Cd2+Cu2+Cr6+≈Pb2+. [Conclusion] The research will provide a basis to explore the effects of heavy metal on environment and ecological system. 展开更多
关键词 Heavy metal Escherichia coli Bacillus subtili growth curve STRESS
下载PDF
Study on Growth and Development Rules and Growth Curve Fitting of Minghua Black Minks
2
作者 荣敏 涂剑锋 +3 位作者 张志明 王淑茗 高峰 邢秀梅 《Agricultural Science & Technology》 CAS 2017年第2期285-286,302,共3页
Growth curves of Minghua black minks at 0-180 days old were fitted and analyzed by using two growth models Logistic and Gompertz. The results showed that the growth curves of Minghua black minks could be fitted very w... Growth curves of Minghua black minks at 0-180 days old were fitted and analyzed by using two growth models Logistic and Gompertz. The results showed that the growth curves of Minghua black minks could be fitted very well by Logistic model and Gompertz model (the degree of fitting FF≥0.99), but Gompertz model was better at fitting and predicting their weight. 展开更多
关键词 Minghua black minks growth curve Non-lineared models Development rules FITTING
下载PDF
ADMISSIBILITY OF LINEAR ESTIMATORS IN A GROWTH CURVE MODEL SUBJECT TO AN INCOMPLETE ELLIPSOIDAL RESTRICTION 被引量:2
3
作者 张尚立 桂文豪 《Acta Mathematica Scientia》 SCIE CSCD 2008年第1期194-200,共7页
This article considers the admissibility of the linear estimators for the regression coefficients in the growth curve model subject to an incomplete ellipsoidal restriction. The necessary and sufficient conditions for... This article considers the admissibility of the linear estimators for the regression coefficients in the growth curve model subject to an incomplete ellipsoidal restriction. The necessary and sufficient conditions for linear estimators to be admissible in classes of the homogeneous and non-homogeneous linear estimators, respectively, are obtained under the quadratic loss function. They are generalizations of some existing results in literature. 展开更多
关键词 growth curve model ADMISSIBILITY linear estimator
下载PDF
ASSESSMENT OF LOCAL INFLUENCE IN A GROWTH CURVE MODEL WITH RAO'S SIMPLE COVARIANCE STRUCTURE 被引量:2
4
作者 白鹏 《Acta Mathematica Scientia》 SCIE CSCD 1999年第S1期555-563,共9页
The present paper deals with the problem of assessing the local influence in a growth curve model with Rao's simple covariance structure. Based on the likelihood displacement,the curvature measure is employed to e... The present paper deals with the problem of assessing the local influence in a growth curve model with Rao's simple covariance structure. Based on the likelihood displacement,the curvature measure is employed to evaluate the effects of some minor perturbations on the statistical inference, thus leading to the large curvature direction, which is the most critical diagnostic statistic in the context of the local influence analysis. As an application, the common covariance-weighted perturbation scheme is thoroughly considered. 展开更多
关键词 growth curve model Rao's simple covariance structure w-model Likelihood displacement curvATURE
下载PDF
ADMISSIBILITY IN THE GENERAL GROWTH CURVE MODEL WITH RESPECT TO RESTRICTED PARAMETER SETS UNDER MATRIX LOSS FUNCTION 被引量:1
5
作者 张尚立 覃红 《Acta Mathematica Scientia》 SCIE CSCD 2010年第1期27-38,共12页
In this paper, we study the issue of admissibility in the growth curve model with respect to restricted parameter sets under matrix loss function. We obtain some neces- sary and sufficient conditions that the linear e... In this paper, we study the issue of admissibility in the growth curve model with respect to restricted parameter sets under matrix loss function. We obtain some neces- sary and sufficient conditions that the linear estimators of KBL are admissible in the class of homogeneous linear estimators and in the class of non-homogeneous linear estimators under the growth curve model with respect to restricted parameter sets, respectively. 展开更多
关键词 growth curve model linear estimation ADMISSIBILITY incomplete ellipsoidalrestriction
下载PDF
BAYESIAN LOCAL INFLUENCE ASSESSMENTS IN A GROWTH CURVE MODEL WITH GENERAL COVARIANCE STRUCTURE 被引量:1
6
作者 白鹏 费宇 《Acta Mathematica Scientia》 SCIE CSCD 2000年第4期563-570,共8页
The objective of this paper is to present a Bayesian approach based on Kullback- Leibler divergence for assessing local influence in a growth curve model with general co- variance structure. Under certain prior distri... The objective of this paper is to present a Bayesian approach based on Kullback- Leibler divergence for assessing local influence in a growth curve model with general co- variance structure. Under certain prior distribution assumption, the Kullback-Leibler di- vergence is used to measure the influence of some minor perturbation on the posterior distribution of unknown parameter. This leads to the diagnostic statistic for detecting which response is locally influential. As an application, the common covariance-weighted perturbation scheme is thoroughly considered. 展开更多
关键词 growth curve model prior and posterior distribution Kullback-Leibler di- vergence Bayesianω-model curvATURE
下载PDF
Environmental Pollution and Economic Growth in China: A Test of the Environmental Kuznets Curve 被引量:2
7
作者 Jiaqi Hu Adrian Hernandez-del-Valle Miguel A. Martinez-Garcia 《Journal of Geoscience and Environment Protection》 2017年第10期92-100,共9页
We apply a two pronged approach to analyze the presence of Environmental Kuznets Curve, EKC, in three types of emissions in the People’s Republic of China from 1994 to 2014: a structural breakpoint analysis and a mod... We apply a two pronged approach to analyze the presence of Environmental Kuznets Curve, EKC, in three types of emissions in the People’s Republic of China from 1994 to 2014: a structural breakpoint analysis and a model based test. We apply it to PM2.5, industrial waste and domestic water pollution time series, and find evidence of EKC in all three types of emissions that require appropriate policy. 展开更多
关键词 Economic growth Environmental KUZNETS curve PM2.5 DOMESTIC Water POLLUTION Industrial Waste China
下载PDF
Comparative Study on Analysis and Fitting of Pudong Chicken Growth Curve 被引量:1
8
作者 Lu Xuelin Zhao Lele +3 位作者 Li Hejun Xu Dong Wu Haomin Xu Weibin 《Animal Husbandry and Feed Science》 CAS 2018年第3期174-177,共4页
The objective of this paper was to study the growth and development laws of Pudong chicken. The growth curve of Pudong chicken (cock and hen) from 0 to 20 weeks was analyzed and fitted with three models(Gompertz, L... The objective of this paper was to study the growth and development laws of Pudong chicken. The growth curve of Pudong chicken (cock and hen) from 0 to 20 weeks was analyzed and fitted with three models(Gompertz, Logistic and Bertalanffy). It was concluded that the growth curves were appropriately fitted with three models, and fitness degree (R2)in growth data of Pudong chicken were all above 0.992. The Bertalanffy model was the most effective with the highest R2 for cock (R^2=0.995) and hen (R^2=0.999), respectively. With further analysis of fitted parameters for Logis- tic model of cock, 0-3 weeks' fitted values were significantly greater than measured values and 4-8 weeks' fitted values were lower than measured values. Compared with Logistic model, the values calculated by Gompertz model and Bertalanffy model were more coincident with the practical measuring values. For hens, 0-3 weeks' fitted values of Logistic model were significantly greater than measured values and 0-2 weeks' fitted values of Gompertz model were slightly greater than measured values, while the values calculated by Bertalanffy model best matched the observed values from actual measure. The results showed that Bertalanffy model used to estimate the growth weight of Pudong chicken was the best while Logistic model was the worst. So the fitness and analysis of growth curves of Pudong chicken are valid, which may be adopted to predict growth and development laws of Pudong chicken and provide reliable data for precise feeding and breeding. 展开更多
关键词 Pudong chicken growth curve FITTING ANALYSIS MODEL
下载PDF
Stochastic simulation of growth curves of Acidithiobacillus ferrooxidans 被引量:1
9
作者 杨宇 彭宏 +2 位作者 邱冠周 柳建设 胡岳华 《Journal of Central South University of Technology》 EI 2006年第5期473-476,共4页
To reveal the low growth rate of Acidithiobacillus ferrooxidans, a stochastic growth model was proposed to analyze growth curves of these bacteria in a batch culture. An algorithm was applied to simulate the bacteria ... To reveal the low growth rate of Acidithiobacillus ferrooxidans, a stochastic growth model was proposed to analyze growth curves of these bacteria in a batch culture. An algorithm was applied to simulate the bacteria population during lag and exponential phase. The results show that the model moderately fits the experimental data. Further, the mean growth constant (K) of growth curves is obtained by fitting the logarithm of the simulating population data versus the generation numbers with the different initial population number (N0) and initial mean activity of population (A0). When No is 300 and 700 respectively, the discrepancy of K value is only 0.91%, however, A0 is 0.34 and 0.38 respectively, the discrepancy of K value is 19.53%. It suggests that the effect of A0 on the lag phase exceeds No, though both parameters could shorten the lag phase by increasing their values. 展开更多
关键词 Acidithiobacillus ferrooxidans stochastic simulation growth curves lag phase
下载PDF
An Improved Unique Fatigue Crack Growth Rate Curve Model and Determination of the Model Shape Exponents 被引量:1
10
作者 Li Sun Yingcai Huang Xiaoping Huang 《Journal of Marine Science and Application》 CSCD 2022年第4期104-115,共12页
It is essential to precisely predict the crack growth,especially the near-threshold regime crack growth under different stress ratios,for most engineering structures consume their fatigue lives in this regime under ra... It is essential to precisely predict the crack growth,especially the near-threshold regime crack growth under different stress ratios,for most engineering structures consume their fatigue lives in this regime under random loading.In this paper,an improved unique curve model is proposed based on the unique curve model,and the determination of the shape exponents of this model is provided.The crack growth rate curves of some materials taken from the literature are evaluated using the improved model,and the results indicate that the improved model can accurately predict the crack growth rate in the nearthreshold and Paris regimes.The improved unique curve model can solve the problems about the shape exponents determination and weak ability around the near-threshold regime meet in the unique curve model.In addition,the shape exponents in the improved model at negative stress ratios are discussed,which can directly adopt that in the unique curve model. 展开更多
关键词 Near-threshold regime Crack growth rate Stress ratio Improved unique curve model Shape exponents
下载PDF
Regularized quantile regression for SNP marker estimation of pig growth curves
11
作者 L.M.A.Barroso M.Nascimento +8 位作者 A.C.C.Nascimento1 F.F.Silva N.V.L.Serao C.D.Cruz M.D.V.Resende F.L.Silva C.F.Azevedo P.S.Lopes S.E.F.Guimaraes 《Journal of Animal Science and Biotechnology》 SCIE CAS CSCD 2017年第4期824-832,共9页
Background: Genomic growth curves are general y defined only in terms of population mean; an alternative approach that has not yet been exploited in genomic analyses of growth curves is the Quantile Regression(QR). Th... Background: Genomic growth curves are general y defined only in terms of population mean; an alternative approach that has not yet been exploited in genomic analyses of growth curves is the Quantile Regression(QR). This methodology allows for the estimation of marker effects at different levels of the variable of interest. We aimed to propose and evaluate a regularized quantile regression for SNP marker effect estimation of pig growth curves, as well as to identify the chromosome regions of the most relevant markers and to estimate the genetic individual weight trajectory over time(genomic growth curve) under different quantiles(levels).Results: The regularized quantile regression(RQR) enabled the discovery, at different levels of interest(quantiles), of the most relevant markers al owing for the identification of QTL regions. We found the same relevant markers simultaneously affecting different growth curve parameters(mature weight and maturity rate): two(ALGA0096701 and ALGA0029483)for RQR(0.2), one(ALGA0096701) for RQR(0.5), and one(ALGA0003761) for RQR(0.8). Three average genomic growth curves were obtained and the behavior was explained by the curve in quantile 0.2, which differed from the others.Conclusions: RQR allowed for the construction of genomic growth curves, which is the key to identifying and selecting the most desirable animals for breeding purposes. Furthermore, the proposed model enabled us to find, at different levels of interest(quantiles), the most relevant markers for each trait(growth curve parameter estimates) and their respective chromosomal positions(identification of new QTL regions for growth curves in pigs). These markers can be exploited under the context of marker assisted selection while aiming to change the shape of pig growth curves. 展开更多
关键词 GENOME association growth curve PIG QTL REGULARIZED QUANTILE regression
下载PDF
Growth Curves Analysis of Five Meat Rabbit Breeds
12
作者 LIHua LONGJi-rong 《Journal of Northeast Agricultural University(English Edition)》 CAS 2001年第2期111-114,共4页
The growth curves of five meat rabbit breeds are fitted in form of Gompertz model.The results are shown as follows:the goodness of fit is higher than 99 50%;considering the body weight at one hundred day?the maximum ... The growth curves of five meat rabbit breeds are fitted in form of Gompertz model.The results are shown as follows:the goodness of fit is higher than 99 50%;considering the body weight at one hundred day?the maximum weight(A)?the instantaneous relative growth rate(K)?the turning weight(W )?the turning age (t )?the early average daily gain (KW ) selection,the Checkered Giant(GG) and the New Zealand White (NN) are better than other meat breeds,the slauthter age should be at the age of 90 day. 展开更多
关键词 meat rabbit growth curves ANALYSIS
下载PDF
Height/Length and Weight Growth Curves and Growth References of Children Aged 0 - 7 in Chongqing by GAMLSS
13
作者 Qian Chen Jiaxiu Liu +1 位作者 Kaocong Tian Zhaohai Liu 《Health》 2020年第2期86-98,共13页
Aim: Using the generalised additive model for location, the scale and shape (GAMLSS), the standard of height (length), weight and percentage curve of children were formulated to understand the growth law in Chongqing ... Aim: Using the generalised additive model for location, the scale and shape (GAMLSS), the standard of height (length), weight and percentage curve of children were formulated to understand the growth law in Chongqing and to provide a reference for clinical and preventive health care work of paediatrics in West China. Methods: Data were collected from the health clinic dataset of children aged 0 - 7 years in the Department of Child Health Care of a Third-Class A hospital in Chongqing from 2010 to 2017. By applying the GAMLSS technology and taking D(μ, σ, ν, τ) as the specific distribution form, BCT as the link function, P-spline function and cubic splines function as the smoothing function, the unit value of age-specific standard deviation of height (length) and weight were obtained, and the percentile map was drawn. Results: Based on the principle of minimum AIC and SBC values, BCT distribution was chosen as the model of the link function. Fitting results of height (length) and weight parameters of boys and girls, standard deviation tables of age and percentile curves were obtained. Conclusions: This study was an exploration of using GAMLSS method to establish a reference value range in the field of children’s growth and development in China. It could supplement the relevant data of Chongqing area for Reference standard for growth and development of children under 7 years of age in China, and also provide a reference for the rational diagnosis of children’s short stature and malnutrition in Chongqing. 展开更多
关键词 CHILDREN HEIGHT WEIGHT growth curve GAMLSS
下载PDF
Establishment and Analysis of Growth Curve of Muchuan Black Chicken
14
作者 Chunlin YU Xiaosong JIANG +10 位作者 Huarui DU Chaowu YANG Zengrong ZHANG Bo XIA Chenming HU Xiaoyan SONG Xia XIONG Li YANG Han PENG Qingyun LI Mohan QIU 《Agricultural Biotechnology》 CAS 2018年第6期115-118,共4页
To find out the growth and development regularity,the growth curves of Muchuan black chicken at the age of 0-21 weeks were established by Logistic,Bertalanffy and Gompertz models in this study.The results showed that ... To find out the growth and development regularity,the growth curves of Muchuan black chicken at the age of 0-21 weeks were established by Logistic,Bertalanffy and Gompertz models in this study.The results showed that all the three models can well fit the growth curve of Muchuan black chicken with a degree above 0.988,while the Gompertz model and the Bertalanffy model was the best for hens and cocks,respectively.Finally,the weight of hens and cocks were analyzed according to their corresponding high fitting models.Results showed that the inflexion age of Muchuan black chicken was 6.8-6.9 weeks old with an inflexion weight of 692.98 g in hens and 805.57 g in cocks.In conclusion,it was feasible to establish the growth curve of Muchuan black chicken with Logistic,Bertalanffy and Gompertz model. 展开更多
关键词 Muchuan BLACK CHICKEN growth and development CUMULATIVE growth growth curve FITTING degree
下载PDF
Admissibility of Linear Estimators in the Growth Curve Model with Respect to Inequality Restriction
15
作者 方龙祥 郭大伟 《Northeastern Mathematical Journal》 CSCD 2007年第6期513-522,共10页
For the growth curve model with respect to inequality restriction: Y = XBZ +ε,ε(0, σ2V I), trNB ≥0, this paper gives some necessary and sufficient conditions for the linear estimator of KBL to be admissible in... For the growth curve model with respect to inequality restriction: Y = XBZ +ε,ε(0, σ2V I), trNB ≥0, this paper gives some necessary and sufficient conditions for the linear estimator of KBL to be admissible in the class of homogeneous linear estimators LH and nonhomogeneous linear estimators LI, respectively, under the quadratic loss function tr(d(Y) - KBL)'(d(Y) - KBL). 展开更多
关键词 inequality restriction ADMISSIBILITY growth curve model linear estimator
下载PDF
High Order Tensor Forms of Growth Curve Models
16
作者 Zerong Lin Dongzhe Liu +2 位作者 Xueying Liu Lingling He Changqing Xu 《Advances in Linear Algebra & Matrix Theory》 2018年第1期18-32,共15页
In this paper, we first study the linear regression model and obtain a norm-minimized estimator of the parameter vector by using the g-inverse and the singular value decomposition of matrix X. We then investigate the ... In this paper, we first study the linear regression model and obtain a norm-minimized estimator of the parameter vector by using the g-inverse and the singular value decomposition of matrix X. We then investigate the growth curve model (GCM) and extend the GCM to a generalized GCM (GGCM) by using high order tensors. The parameter estimations in GGCMs are also achieved in this way. 展开更多
关键词 TENSOR GENERALIZED Linear MODEL growth curve MODEL Parameter Estimation GENERALIZED Inverse
下载PDF
Growth and Inequality in Indonesia: Does Kuznets Curve Hold?
17
作者 G. A. Diah Utari Retni Cristina 《Journal of Modern Accounting and Auditing》 2015年第2期93-111,共19页
Sustainable economic growth has put Indonesia as a middle-income country (MIC) and currently, the level of per capita income has already exceeded US$3,000. The increase in income per capita is followed by the increa... Sustainable economic growth has put Indonesia as a middle-income country (MIC) and currently, the level of per capita income has already exceeded US$3,000. The increase in income per capita is followed by the increasing number of middle-class population and the reduction in poverty. However, it has not been accompanied by declining inequality that reflects the quality of economic growth. According to Kuznets theory, an increase in inequality is a common problem in the process of economic growth. Inequality will further decline after the country has reached a certain threshold level of income. This study aims to analyze the trend and nature of income inequality in Indonesia and to test whether the Kuznets Curve holds. This paper used dynamic panel method with 26 provincial panel data from 2000 to 2011. The empirical result proves the existence of inverted U-shaped Kuznets Curve in Indonesia and it may have the turning points when the real GDP per capita in each province reached Rp. 179.41 million/year or around US$17.000. For the determinant of inequality in Indonesia, this study found that the percentage of urban population, inflation, and share of agricultural sector contributed to the increase of inequality, while high-level education and share of industrial sector are associated with the lower level of inequality. 展开更多
关键词 growth middle class POVERTY INEQUALITY Kuznets curve dynamic panel
下载PDF
GENERAL ADMISSIBLE LINEARESTIMATORS IN RESTRICEDGROWTH CURVE MODEL
18
作者 CHEN QINGPING ( Yunyang Teacher College ) 《郧阳师范高等专科学校学报》 1996年第3期1-6,共6页
In this paper, we give a class of fuation and use to dicuss general admissibility according to general optimality ceriteria defined uader restricted growth curve model. General admissible characterization are obtained... In this paper, we give a class of fuation and use to dicuss general admissibility according to general optimality ceriteria defined uader restricted growth curve model. General admissible characterization are obtained. Moreover, these conditions are then utilize to characterize infulueace that restrictions involved in growth curve model have on the class of admissible linear 展开更多
关键词 growth curve model LINEAR RESTRICTION Generaladmissble
下载PDF
应用CurveExpert软件拟合生长曲线模型 被引量:7
19
作者 李少斌 胡江 +2 位作者 王继卿 刘秀 罗玉柱 《畜牧兽医杂志》 2012年第5期57-59,共3页
介绍了应用CurveExpert软件拟合动物生长曲线模型的方法,并对该软件分析结果的可靠性进行了分析。结果表明,应用CurveExpert拟合动物生长曲线模型操作简便,结果准确,可为相同或类似曲线拟合提供参考。
关键词 生长曲线模型 软件 参数估计
下载PDF
Inflation and Unemployment Trade-off:Is Phillips Curve True for African Developing Countries?Evidence from Sudan
20
作者 Omer Allagabo Omer Mustafa 《Journal of Economic Science Research》 2021年第3期35-43,共9页
The relationship between wage inflation and unemployment(Phillips Curve)is controversial in economic thought,and the controversy is centered around whether there is always a trade-off or not.If this relati-onship is n... The relationship between wage inflation and unemployment(Phillips Curve)is controversial in economic thought,and the controversy is centered around whether there is always a trade-off or not.If this relati-onship is negative it is called The short-run Fillips Curve.However,in the long run,this relationship may probable not exist.The matter of how inflation and unemployment influence economic growth,is debatably among macroeconomic policymakers.This study examines the behavior of the Phillips Curve in Sudan and its effect on economic growth. 展开更多
关键词 Phillips curve Trade-off Economic growth SUDAN
下载PDF
上一页 1 2 127 下一页 到第
使用帮助 返回顶部