Power flow(PF)is one of the most important calculations in power systems.The widely-used PF methods are the Newton-Raphson PF(NRPF)method and the fast-decoupled PF(FDPF)method.In smart grids,power generations and load...Power flow(PF)is one of the most important calculations in power systems.The widely-used PF methods are the Newton-Raphson PF(NRPF)method and the fast-decoupled PF(FDPF)method.In smart grids,power generations and loads become intermittent and much more uncertain,and the topology also changes more frequently,which may result in significant state shifts and further make NRPF or FDPF difficult to converge.To address this problem,we propose a data-driven PF(DDPF)method based on historical/simulated data that includes an offline learning stage and an online computing stage.In the offline learning stage,a learning model is constructed based on the proposed exact linear regression equations,and then the proposed learning model is solved by the ridge regression(RR)method to suppress the effect of data collinearity.In online computing stage,the nonlinear iterative calculation is not needed.Simulation results demonstrate that the proposed DDPF method has no convergence problem and has much higher calculation efficiency than NRPF or FDPF while ensuring similar calculation accuracy.展开更多
Estimations of parametric functions under a system of linear regression equations with correlated errors across equations involve many complicated operations of matrices and their generalized inverses. In the past sev...Estimations of parametric functions under a system of linear regression equations with correlated errors across equations involve many complicated operations of matrices and their generalized inverses. In the past several years, a useful tool -- the matrix rank method was utilized to simplify various complicated operations of matrices and their generalized inverses. In this paper, we use the matrix rank method to derive a variety of new algebraic and statistical properties for the best linear unbiased estimators (BLUEs) of parametric functions under the system. In particular, we give the necessary and sufficient conditions for some equalities, additive and block decompositions of BLUEs of parametric functions under the system to hold.展开更多
Deformation modulus of rock mass is one of the input parameters to most rock engineering designs and constructions.The field tests for determination of deformation modulus are cumbersome,expensive and time-consuming.T...Deformation modulus of rock mass is one of the input parameters to most rock engineering designs and constructions.The field tests for determination of deformation modulus are cumbersome,expensive and time-consuming.This has prompted the development of various regression equations to estimate deformation modulus from results of rock mass classifications,with rock mass rating(RMR)being one of the frequently used classifications.The regression equations are of different types ranging from linear to nonlinear functions like power and exponential.Bayesian method has recently been developed to incorporate regression equations into a Bayesian framework to provide better estimates of geotechnical properties.The question of whether Bayesian method improves the estimation of geotechnical properties in all circumstances remains open.Therefore,a comparative study was conducted to assess the performances of regression and Bayesian methods when they are used to characterize deformation modulus from the same set of RMR data obtained from two project sites.The study also investigated the performance of different types of regression equations in estimation of the deformation modulus.Statistics,probability distributions and prediction indicators were used to assess the performances of regression and Bayesian methods and different types of regression equations.It was found that power and exponential types of regression equations provide a better estimate than linear regression equations.In addition,it was discovered that the ability of the Bayesian method to provide better estimates of deformation modulus than regression method depends on the quality and quantity of input data as well as the type of the regression equation.展开更多
The relationship between the change of forest resources and climatic factor in the, “Three-North” region of China were studied in this paper. The predicting equations of climatic factor (dependent variable) with reg...The relationship between the change of forest resources and climatic factor in the, “Three-North” region of China were studied in this paper. The predicting equations of climatic factor (dependent variable) with regional independent variable (longitude, latitude and altitude) and stand independent variable (forest coverage rate), were developed by extensively using the linear and nonlinear regression methods. With these models, we can calculate the ecological benefit of Shelter-belt forest.展开更多
This study describes the different parameters used to derive the allometric equation for calculating the biomass of an invasive woody shrub Lantana camara L.from the subtropical conditions of western Himalaya.It ident...This study describes the different parameters used to derive the allometric equation for calculating the biomass of an invasive woody shrub Lantana camara L.from the subtropical conditions of western Himalaya.It identifies the most accurate and convenient method for biomass calculation by comparing destructive with nondestructive methodology.Different parameters were measured on a wide range of Lantana from different community levels for the non-destructive calculation of total aboveground biomass.Different explanatory variables were identified and measured such as basal diameter either as a single independent variable or in combination with plant height.The other suitable combinations of available independent variables include crown length,crown width,crown area,crown volume and coverage of the plant.Amongst the wide range of allometric equations used with different variables,the equation with D2 H as a variable was found to be the most suitable estimator of biomass calculation for Lantana.Sahastradhara,being the most disturbed area due to its high tourist activity round the year,showed maximum coverage(58.57 % ha-1),highest biomass(13,559.60 kg ha-1) and carbon density(6,373.01 kg ha-1)of Lantana.The degree of Lantana’s invasiveness in subtropical conditions was also calculated on the basis of importance value index(IVI).The maximum IVI(22.77)and mean coverage(26.8 % ha-1) was obtained from the areas near Jolly Grant airport,indicating that physically disturbed areas are more suitable for the growth of Lantana,which may significantly increase shrub biomass.The importance of incorporating allometric equations in calculation of shrub biomass,and its role in atmospheric carbon assimilation has thus been highlighted through the findings of this study.展开更多
Carbon (C) sequestration through plantations is one of the important mitigation measures for rising levels of carbon dioxide and other greenhouse gases in the atmosphere. This study aimed to assess C stocks and thei...Carbon (C) sequestration through plantations is one of the important mitigation measures for rising levels of carbon dioxide and other greenhouse gases in the atmosphere. This study aimed to assess C stocks and their sequestration rate, and to develop allometric models for estimation of C stocking in age-series young teak (Tectona grandis) planta- tions (1, 5, 11, 18, 24 and 30 years) by using biomass and productivity estimation and regression, respectively. These plantations were raised in tropical moist deciduous forests of Kumaun Himalayan tarai. Total C stocks estimated for these plantations were 1.6, 15.8, 35.4, 39.0, 61.5 and 73.2 Mg ha-1, respectively. Aboveground and belowground C storage in- creased with increasing plantation age; however, the range of their percentage contribution showed little variation (87.8-88.2 and 11.7-12.7 %, respectively), The rate of C sequestration for these respective plantations was 1.06, 6.95, 5.46, 5.42, 3.39 and 5.37 Mg ha-1 a-1. Forty percent of the aboveground annual storage was retained in the tree while 60 % was released in the form of foliage, twigs, and fruit litter. In the case of total (tree) annual production, 43 % was retained while 57 % was released as litter including root. C stock, C sequestration rate, accumulation ratio (1.4-18.1), root:shoot C ratio (0.61--0.13) and production efficiency (0.01-0.18) were comparable to some previous reports for other species and forests. These data could be useful in deciding the harvesting age for young teak with respect to C storage and sequestrationrate. Four allometric models using linear regression equations were developed between biomass (twice the C stock) and diameter, girth, and height of the tree at different ages. The diameter model was found more suitable for C stock predic- tion in similar areas.展开更多
The artemisia weevil, Adosomus sp., has become an important wormwood (Artemisa ordosoca and A. sphaerocephala) pest in recent years in Ningxia Province, China. The number of larval instars should be determined befor...The artemisia weevil, Adosomus sp., has become an important wormwood (Artemisa ordosoca and A. sphaerocephala) pest in recent years in Ningxia Province, China. The number of larval instars should be determined before further studies on its life history, biology and integrate management of pest (IMP). In this study, we measured the length and width of head capsule, based on frequency histograms and Dyar's law, from which we concluded that the larvae ofAdosomus sp. have four instars. Of the two variables measured, the width of head capsule provided the best division of instars. The average width of head capsule of the 1st instar larvae was 1.348±0.152 mm, the 2nd 2.109±0.199 mm, the 3rd 3.563±0.492 mm and the 4th 5.974±0.581 mm.展开更多
Clam Meretrix lamarchii is delicious seafood with high economic value. The M. lamarchii in present market is mainly collected from wild population due to the lack of large-scale artificial seed production. In 2013,we ...Clam Meretrix lamarchii is delicious seafood with high economic value. The M. lamarchii in present market is mainly collected from wild population due to the lack of large-scale artificial seed production. In 2013,we carried out the artificial seedling exploration of M. Lamarchii. The current study utilized several statistical methods to analyze the effects of morphological traits on M. Lamarchii,which may provide knowledge for clam quality seedlings breeding work. The samples of M. Lamarchii were randomly sampled from Donghai Island,Zhanjiang. Shell length( SL),shell width( SW),shell height( SH),ligament length( Li L),lunule length( Lu L) and total weight( TW) of two-year-old M. Lamarchii were measured. A correlation coefficient matrix was constructed based on the results,where the total weight was set as the dependent variable and others as independent variables. Path coefficient and correlation index were calculated,and the major phenotypic characters were determined. The results showed that all the correlation coefficients between independent variables and dependent variable were significant( P < 0. 01),with an exception of the lunule length( P > 0. 05). The effects of the shell length,shell width,and shell height on the total weight were significant( P < 0. 01),and the shell length had dominant effect on the weight as a key effective factor. The multiple regression equation between the weight and the other traits was established as Y;=- 126. 784 + 1. 249X;+ 2. 036X;+ 0. 911 X;,where YWis total weight,X;,X;and X;are the shell length,shell width and shell height,respectively. The current study may contribute to the artificial breeding of the species.展开更多
A renovation project of miniaturization and high efficiency is provided for the hot blast stove .The experimental data tested feasibility of the new-type swirl flow hot blast stove. The normal and hot state experiment...A renovation project of miniaturization and high efficiency is provided for the hot blast stove .The experimental data tested feasibility of the new-type swirl flow hot blast stove. The normal and hot state experiments have been done through changing the angle of gas entering into the regenerator. Factors influencing pressure drop have been studied and analyzed. The experimental results can be formulated in the form of the Ergun equation. The regression equation is obtained. And two modified coefficients are offered to the regenerator pressure drop of the new-type swirl flow hot blast stove.展开更多
The soil CO2 evolution rate was measured in a virpin Korean pine forest. The results in June showed that the lowest value of evolution rate was 220 mg /(m2·h) and appeared at 6:00 a.m. The highest value was 460 m...The soil CO2 evolution rate was measured in a virpin Korean pine forest. The results in June showed that the lowest value of evolution rate was 220 mg /(m2·h) and appeared at 6:00 a.m. The highest value was 460 mg /(m2·h) at 18:00. The rates of CO2 evolution were related with soil temperature. On the basis of the constructed regression equation and the monthly average values of temperature, the magnitude of CO2 evolution from Korean pine forest soil was 10.4 t /hm2 during a growing season.展开更多
The research work was carried out to compare and evaluate the extractability of cationic micronutrients(Zn,Cu,Fe and Mn)using widely employed diethylene triamine pentaacetic acid(DTPA)-triethanolamine(TEA)-CaCl2 metho...The research work was carried out to compare and evaluate the extractability of cationic micronutrients(Zn,Cu,Fe and Mn)using widely employed diethylene triamine pentaacetic acid(DTPA)-triethanolamine(TEA)-CaCl2 method with that of multinutrient extractant(ammonium bicarbonate(AB)-DTPA)in Inceptisols,Alfisols and Entisols in the erstwhile united Andhra Pradesh.The percent variation of extraction of Zn was higher in soils with DTPA-TEA-CaCl2 over AB-DTPA method in all the soil orders(types)in the range of 35.3% to 46.2%.AB-DTPA extracted high amounts of Cu to an extent of 10%-21% in Entisols and Alfisls,respectively.In Inceptisols both extracatants extracted equal amounts of Cu.AB-DTPA extracted high amounts of Fe 13% and 18% in Alfisols and Entisols compared to that of DTPA-TEA-CaCl2 method and DTPA-TEA-CaCl2 method was good extract for Fe in Inceptisols and even for Mn in Alfisols.The amounts of micronutrient contents extracted were found to be highly and significantly correlated with soil properties like electrical conductivity(EC)and organic carbon(OC).The individual micronutrient contents of Zn,Cu and Fe extracted by DTPA-TEA-CaCl2 methods were found to be highly correlated with that of AB-DTPA extractant.However,such correlation was not observed for Mn extraction when all soils were grouped.展开更多
To evaluate the relationship between measures of body composition in obese adolescents by the methods of bioelectrical impedance analysis, deuterium oxide dilution and anthropometric measures, proposing an equation. T...To evaluate the relationship between measures of body composition in obese adolescents by the methods of bioelectrical impedance analysis, deuterium oxide dilution and anthropometric measures, proposing an equation. The variables were weight, height, BMI, triceps and subscapular skinfold thickness, waist and arm muscle circumference, lean body mass, fat mass and total body water by bioelectrical impedance and deuterium oxide dilution methods. The study included 40 obese adolescents, 45% male, age distribution was 2.42 ± 1.19 years and females 55%, and the predominant age was 12.61 ± 1.78. Linear regression equations were developed, capable of predicting body composition from information supplied by the method of deuterium oxide dilution (gold standard), bioelectrical impedance and anthropometry. The variables gender, age, height, arm circumference, triceps and suprailiac skin fold thickness, resistance and reactance were used to estimate lean body mass, fat mass and total body water by the method of deuterium and significantly correlated with variables, resistance, reactance, sex and total body water (TBW) by bioimpedance method. Among the equations developed, five were suitable for this sample, therefore, it is suggested that more studies should be done to test the applicability of the equations in other samples so that we can validate the equations encountered in obese adolescents.展开更多
Culm characteristics of Melocanna baccifera, locally 'muli', culms at five different culm ages of 11 girth classes (5-6 to 15-16 cm) were studied from Cachar Dis- trict of southern Assam, northeast India. We recor...Culm characteristics of Melocanna baccifera, locally 'muli', culms at five different culm ages of 11 girth classes (5-6 to 15-16 cm) were studied from Cachar Dis- trict of southern Assam, northeast India. We recorded internode length, internode diameter, number of internodes per culm, total culm height, total culm green weight and total culm volume of all five culm age classes. Data were gathered on 165 culms, each culm age class containing 33 culms with 3 culms per girth class. Culm height ranged from 3.2 to 15.3 m with highest mean of 9.15 m (in threeyear old culms) and maximum culm height was recorded in four-year old culms. Highest mean and maximum internode length (27.45 and 54.2 cm, respectively), internode diameter (3.12 and 4.75 cm, respectively) and total culm green weight (5.42 and 12.87 kg/culm, respectively) were recorded in three-year old culms and lowest in current-year culms. Best fitted regression models for all parameters were developed. Significant linear relationships between culm green weight and culm solid volume were documented for all five culm age classes. Their corresponding best-fit regression models were also developed.展开更多
Axial air-assisted sprayers can distribute pesticides efficiently in kiwifruit orchards.Because of improper parameter settings,most sprayers deliver either too much or too little pesticide.To identify appropriate spra...Axial air-assisted sprayers can distribute pesticides efficiently in kiwifruit orchards.Because of improper parameter settings,most sprayers deliver either too much or too little pesticide.To identify appropriate sprayer parameters for kiwifruit trees,the vertical distribution profiles of the applied liquid spray were examined in this study.The effects of spray fan speed(SFS),spray pressure(SP)and spray distance(SD)on the distributions of the sprayed liquid in the vertical profiles were studied.Combined actions of the above parameters were systematically analysed using the quadratic general rotary design test method.Regression equations for the spray liquid distributions and working factors are presented.Field confirmation experiments were carried out to optimize the parameters.Data analysis showed that the optional sprayer working parameters are those of Group 3,with an SFS equal to 1900 r/min and SP equal to 3.25 MPa.The results of this study provide a reference for future applications of this type of axial air-assisted sprayer in kiwifruit orchards.展开更多
Objective To systemically explore the range of visual angles that affect visual acuity, and to establish the relationship between the P 1 component (peak latency -100 ms) of the pattern-reversal visual-evoked potent...Objective To systemically explore the range of visual angles that affect visual acuity, and to establish the relationship between the P 1 component (peak latency -100 ms) of the pattern-reversal visual-evoked potential (PRVEP) and the visual acuity at particular visual angles. Methods Two hundred and ten volunteers were divided into seven groups, according to visual acuity as assessed by the standard logarithmic visual acuity chart (SLD-II). For each group, the PRVEP components were elicited in response to visual angle presentations at 8°, 4°, 2°, 1°/60', 30', 15', and 7.5', in the whiteblack chess-board reversal mode with a contrast level of 100% at a frequency of 2 Hz. Visual stimuli were presented monocularly, and 200 presentations were averaged for each block of trials. The early and stable component P1 was recorded at the mid-line of the occipital region (Oz) and analyzed with SPSS 13.00. Results (1) Oz had the maximum Pl amplitude; there was no significant difference between genders or for interocular comparison in normal controls and subjects with optic myopia. (2) The P1 latency decreased slowly below 30', then increased rapidly. The P1 amplitude initially increased with check size, and was maximal at -1° and -30'. (3) The P1 latency in the group with visual acuity 〈0.2 was signifi- cantly different at 8°, 15' and 7.5', while the amplitude differed at all visual angles, compared with the group with normal vision. Differences in P1 for the groups with 0.5 and 0.6 acuity were only present at visual angles 〈1°. (4) Regression analysis showed that the P1 latency and amplitude were associated with visual acuity over the full range of visual angles. There was a moderate correlation at visual angles 〈30'. Regression equations were calculated for the P1 components and visual acuity, based on visual angle. Conclusion (1) Visual angle should be taken into consideration when exploring the function of the visual pathway, especially visual acuity. A visual angle -60' might be appropriate when using PRVEP com- ponents to evaluate poor vision and to identify malingerers. (2) Increased P1 amplitude and decreased P1 latency were as- sociated with increasing visual acuity, and the P1 components displayed a linear correlation with visual acuity, especially in the range of optimal visual angles. Visual acuity can be deduced from P 1 based on visual angle.展开更多
The purpose of this study was to develop an equation to predict strength for seven common resistance training exercises using anthropometric and demographic measures.One-hundred forty-seven healthy adults(74 males,73 ...The purpose of this study was to develop an equation to predict strength for seven common resistance training exercises using anthropometric and demographic measures.One-hundred forty-seven healthy adults(74 males,73 females,3512 yr,17410 cm,8819 kg)volunteered to participate.Body composition values(regional/total)and body dimensions were assessed using dual-energy x-ray absorptiometry(DEXA).Subjects underwent the following maximal strength assessments:Leg Press,Chest Press,Leg Curl,Lat Pulldown,Leg Extension,Tri-ceps Pushdown,and Biceps Curl.Multiple linear regression with stepwise removal was used to determine the best model to predict maximal strength for each exercise.Independent predictor variables identified(p<0.05)were height(cm);weight(kg);BMI;age;sex(0=F,1=M);regional lean masses(LM,kg);fat mass(FM,kg);fat free mass(FFM,kg);percent fat(%BF);arm,leg,and trunk lengths(AL,LL,TL;cm);and shoulder width(SW,cm).Analyses were performed with and without regional measures to accommodate scenarios where DEXA is un-available.All models presented were significant(p<0.05,R^(2)=0.68-0.83),with regional models producing the greatest accuracy.Results indicate that maximal strength for individual resistance exercises can be reasonably estimated in adults.展开更多
Reliable estimation of stature from skeletal remains will continue to play an important role in assessing a variety of forensic anthropological and archaeological issues.In the present study,we studied and collated da...Reliable estimation of stature from skeletal remains will continue to play an important role in assessing a variety of forensic anthropological and archaeological issues.In the present study,we studied and collated data on the morphometry of the tibia as well as analyzing its segment that shows significant correlation with its maximum length and consequently formulating linear regression equations for estimating maximum tibia length(MTL)which is specific for the Nigeria population.A total number of 68 intact adult human tibia bones were used(35 right and 33 left).Thirteen anthropometric parameters were measured including the MTL.The mean differences between right and left bones of all the measured parameter were not statistically significant except for the mean shaft circumference.The correlation coefficient between MTL and the bicondylar tibial width(BTW),anterior‑posterior intercondylar diameter(APID),anterior‑posterior diameter of medial condyle(APDMC),midshaft transverse diameter(MSTD),and distal articular surface length(DASL)were seen to be significant(P<0.05)only in the right tibia;therefore,the linear regression equations for estimation of MTL from these parameters for the right tibia were also significant(P<0.05).The results of our study concluded that it is possible to estimate the maximum length of the right tibia from the BTW,APID,APDMC,MSTD,and DASL with relative accuracy.Our study may be useful for forensic investigations for the identification of the remains of unknown bodies in a Nigerian population.展开更多
基金supported in part by National Natural Science Foundation of China(No.52077076)in part by the State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources(No.LAPS202118)。
文摘Power flow(PF)is one of the most important calculations in power systems.The widely-used PF methods are the Newton-Raphson PF(NRPF)method and the fast-decoupled PF(FDPF)method.In smart grids,power generations and loads become intermittent and much more uncertain,and the topology also changes more frequently,which may result in significant state shifts and further make NRPF or FDPF difficult to converge.To address this problem,we propose a data-driven PF(DDPF)method based on historical/simulated data that includes an offline learning stage and an online computing stage.In the offline learning stage,a learning model is constructed based on the proposed exact linear regression equations,and then the proposed learning model is solved by the ridge regression(RR)method to suppress the effect of data collinearity.In online computing stage,the nonlinear iterative calculation is not needed.Simulation results demonstrate that the proposed DDPF method has no convergence problem and has much higher calculation efficiency than NRPF or FDPF while ensuring similar calculation accuracy.
基金Supported by National Natural Science Foundation of China (Grant No. 70871073)
文摘Estimations of parametric functions under a system of linear regression equations with correlated errors across equations involve many complicated operations of matrices and their generalized inverses. In the past several years, a useful tool -- the matrix rank method was utilized to simplify various complicated operations of matrices and their generalized inverses. In this paper, we use the matrix rank method to derive a variety of new algebraic and statistical properties for the best linear unbiased estimators (BLUEs) of parametric functions under the system. In particular, we give the necessary and sufficient conditions for some equalities, additive and block decompositions of BLUEs of parametric functions under the system to hold.
文摘Deformation modulus of rock mass is one of the input parameters to most rock engineering designs and constructions.The field tests for determination of deformation modulus are cumbersome,expensive and time-consuming.This has prompted the development of various regression equations to estimate deformation modulus from results of rock mass classifications,with rock mass rating(RMR)being one of the frequently used classifications.The regression equations are of different types ranging from linear to nonlinear functions like power and exponential.Bayesian method has recently been developed to incorporate regression equations into a Bayesian framework to provide better estimates of geotechnical properties.The question of whether Bayesian method improves the estimation of geotechnical properties in all circumstances remains open.Therefore,a comparative study was conducted to assess the performances of regression and Bayesian methods when they are used to characterize deformation modulus from the same set of RMR data obtained from two project sites.The study also investigated the performance of different types of regression equations in estimation of the deformation modulus.Statistics,probability distributions and prediction indicators were used to assess the performances of regression and Bayesian methods and different types of regression equations.It was found that power and exponential types of regression equations provide a better estimate than linear regression equations.In addition,it was discovered that the ability of the Bayesian method to provide better estimates of deformation modulus than regression method depends on the quality and quantity of input data as well as the type of the regression equation.
文摘The relationship between the change of forest resources and climatic factor in the, “Three-North” region of China were studied in this paper. The predicting equations of climatic factor (dependent variable) with regional independent variable (longitude, latitude and altitude) and stand independent variable (forest coverage rate), were developed by extensively using the linear and nonlinear regression methods. With these models, we can calculate the ecological benefit of Shelter-belt forest.
文摘This study describes the different parameters used to derive the allometric equation for calculating the biomass of an invasive woody shrub Lantana camara L.from the subtropical conditions of western Himalaya.It identifies the most accurate and convenient method for biomass calculation by comparing destructive with nondestructive methodology.Different parameters were measured on a wide range of Lantana from different community levels for the non-destructive calculation of total aboveground biomass.Different explanatory variables were identified and measured such as basal diameter either as a single independent variable or in combination with plant height.The other suitable combinations of available independent variables include crown length,crown width,crown area,crown volume and coverage of the plant.Amongst the wide range of allometric equations used with different variables,the equation with D2 H as a variable was found to be the most suitable estimator of biomass calculation for Lantana.Sahastradhara,being the most disturbed area due to its high tourist activity round the year,showed maximum coverage(58.57 % ha-1),highest biomass(13,559.60 kg ha-1) and carbon density(6,373.01 kg ha-1)of Lantana.The degree of Lantana’s invasiveness in subtropical conditions was also calculated on the basis of importance value index(IVI).The maximum IVI(22.77)and mean coverage(26.8 % ha-1) was obtained from the areas near Jolly Grant airport,indicating that physically disturbed areas are more suitable for the growth of Lantana,which may significantly increase shrub biomass.The importance of incorporating allometric equations in calculation of shrub biomass,and its role in atmospheric carbon assimilation has thus been highlighted through the findings of this study.
文摘Carbon (C) sequestration through plantations is one of the important mitigation measures for rising levels of carbon dioxide and other greenhouse gases in the atmosphere. This study aimed to assess C stocks and their sequestration rate, and to develop allometric models for estimation of C stocking in age-series young teak (Tectona grandis) planta- tions (1, 5, 11, 18, 24 and 30 years) by using biomass and productivity estimation and regression, respectively. These plantations were raised in tropical moist deciduous forests of Kumaun Himalayan tarai. Total C stocks estimated for these plantations were 1.6, 15.8, 35.4, 39.0, 61.5 and 73.2 Mg ha-1, respectively. Aboveground and belowground C storage in- creased with increasing plantation age; however, the range of their percentage contribution showed little variation (87.8-88.2 and 11.7-12.7 %, respectively), The rate of C sequestration for these respective plantations was 1.06, 6.95, 5.46, 5.42, 3.39 and 5.37 Mg ha-1 a-1. Forty percent of the aboveground annual storage was retained in the tree while 60 % was released in the form of foliage, twigs, and fruit litter. In the case of total (tree) annual production, 43 % was retained while 57 % was released as litter including root. C stock, C sequestration rate, accumulation ratio (1.4-18.1), root:shoot C ratio (0.61--0.13) and production efficiency (0.01-0.18) were comparable to some previous reports for other species and forests. These data could be useful in deciding the harvesting age for young teak with respect to C storage and sequestrationrate. Four allometric models using linear regression equations were developed between biomass (twice the C stock) and diameter, girth, and height of the tree at different ages. The diameter model was found more suitable for C stock predic- tion in similar areas.
基金supported by the National Project of ScienceTechnology for the 11th Five-Year Plan in China (Grant No. 2006BADO8A12)
文摘The artemisia weevil, Adosomus sp., has become an important wormwood (Artemisa ordosoca and A. sphaerocephala) pest in recent years in Ningxia Province, China. The number of larval instars should be determined before further studies on its life history, biology and integrate management of pest (IMP). In this study, we measured the length and width of head capsule, based on frequency histograms and Dyar's law, from which we concluded that the larvae ofAdosomus sp. have four instars. Of the two variables measured, the width of head capsule provided the best division of instars. The average width of head capsule of the 1st instar larvae was 1.348±0.152 mm, the 2nd 2.109±0.199 mm, the 3rd 3.563±0.492 mm and the 4th 5.974±0.581 mm.
文摘Clam Meretrix lamarchii is delicious seafood with high economic value. The M. lamarchii in present market is mainly collected from wild population due to the lack of large-scale artificial seed production. In 2013,we carried out the artificial seedling exploration of M. Lamarchii. The current study utilized several statistical methods to analyze the effects of morphological traits on M. Lamarchii,which may provide knowledge for clam quality seedlings breeding work. The samples of M. Lamarchii were randomly sampled from Donghai Island,Zhanjiang. Shell length( SL),shell width( SW),shell height( SH),ligament length( Li L),lunule length( Lu L) and total weight( TW) of two-year-old M. Lamarchii were measured. A correlation coefficient matrix was constructed based on the results,where the total weight was set as the dependent variable and others as independent variables. Path coefficient and correlation index were calculated,and the major phenotypic characters were determined. The results showed that all the correlation coefficients between independent variables and dependent variable were significant( P < 0. 01),with an exception of the lunule length( P > 0. 05). The effects of the shell length,shell width,and shell height on the total weight were significant( P < 0. 01),and the shell length had dominant effect on the weight as a key effective factor. The multiple regression equation between the weight and the other traits was established as Y;=- 126. 784 + 1. 249X;+ 2. 036X;+ 0. 911 X;,where YWis total weight,X;,X;and X;are the shell length,shell width and shell height,respectively. The current study may contribute to the artificial breeding of the species.
文摘A renovation project of miniaturization and high efficiency is provided for the hot blast stove .The experimental data tested feasibility of the new-type swirl flow hot blast stove. The normal and hot state experiments have been done through changing the angle of gas entering into the regenerator. Factors influencing pressure drop have been studied and analyzed. The experimental results can be formulated in the form of the Ergun equation. The regression equation is obtained. And two modified coefficients are offered to the regenerator pressure drop of the new-type swirl flow hot blast stove.
文摘The soil CO2 evolution rate was measured in a virpin Korean pine forest. The results in June showed that the lowest value of evolution rate was 220 mg /(m2·h) and appeared at 6:00 a.m. The highest value was 460 mg /(m2·h) at 18:00. The rates of CO2 evolution were related with soil temperature. On the basis of the constructed regression equation and the monthly average values of temperature, the magnitude of CO2 evolution from Korean pine forest soil was 10.4 t /hm2 during a growing season.
文摘The research work was carried out to compare and evaluate the extractability of cationic micronutrients(Zn,Cu,Fe and Mn)using widely employed diethylene triamine pentaacetic acid(DTPA)-triethanolamine(TEA)-CaCl2 method with that of multinutrient extractant(ammonium bicarbonate(AB)-DTPA)in Inceptisols,Alfisols and Entisols in the erstwhile united Andhra Pradesh.The percent variation of extraction of Zn was higher in soils with DTPA-TEA-CaCl2 over AB-DTPA method in all the soil orders(types)in the range of 35.3% to 46.2%.AB-DTPA extracted high amounts of Cu to an extent of 10%-21% in Entisols and Alfisls,respectively.In Inceptisols both extracatants extracted equal amounts of Cu.AB-DTPA extracted high amounts of Fe 13% and 18% in Alfisols and Entisols compared to that of DTPA-TEA-CaCl2 method and DTPA-TEA-CaCl2 method was good extract for Fe in Inceptisols and even for Mn in Alfisols.The amounts of micronutrient contents extracted were found to be highly and significantly correlated with soil properties like electrical conductivity(EC)and organic carbon(OC).The individual micronutrient contents of Zn,Cu and Fe extracted by DTPA-TEA-CaCl2 methods were found to be highly correlated with that of AB-DTPA extractant.However,such correlation was not observed for Mn extraction when all soils were grouped.
文摘To evaluate the relationship between measures of body composition in obese adolescents by the methods of bioelectrical impedance analysis, deuterium oxide dilution and anthropometric measures, proposing an equation. The variables were weight, height, BMI, triceps and subscapular skinfold thickness, waist and arm muscle circumference, lean body mass, fat mass and total body water by bioelectrical impedance and deuterium oxide dilution methods. The study included 40 obese adolescents, 45% male, age distribution was 2.42 ± 1.19 years and females 55%, and the predominant age was 12.61 ± 1.78. Linear regression equations were developed, capable of predicting body composition from information supplied by the method of deuterium oxide dilution (gold standard), bioelectrical impedance and anthropometry. The variables gender, age, height, arm circumference, triceps and suprailiac skin fold thickness, resistance and reactance were used to estimate lean body mass, fat mass and total body water by the method of deuterium and significantly correlated with variables, resistance, reactance, sex and total body water (TBW) by bioimpedance method. Among the equations developed, five were suitable for this sample, therefore, it is suggested that more studies should be done to test the applicability of the equations in other samples so that we can validate the equations encountered in obese adolescents.
基金financially supported by University Grants Commission,New Delhi
文摘Culm characteristics of Melocanna baccifera, locally 'muli', culms at five different culm ages of 11 girth classes (5-6 to 15-16 cm) were studied from Cachar Dis- trict of southern Assam, northeast India. We recorded internode length, internode diameter, number of internodes per culm, total culm height, total culm green weight and total culm volume of all five culm age classes. Data were gathered on 165 culms, each culm age class containing 33 culms with 3 culms per girth class. Culm height ranged from 3.2 to 15.3 m with highest mean of 9.15 m (in threeyear old culms) and maximum culm height was recorded in four-year old culms. Highest mean and maximum internode length (27.45 and 54.2 cm, respectively), internode diameter (3.12 and 4.75 cm, respectively) and total culm green weight (5.42 and 12.87 kg/culm, respectively) were recorded in three-year old culms and lowest in current-year culms. Best fitted regression models for all parameters were developed. Significant linear relationships between culm green weight and culm solid volume were documented for all five culm age classes. Their corresponding best-fit regression models were also developed.
基金The authors acknowledge that this work was financially supported by the National Key Research and Development Program(No.2016YFD0200700)the National Key R&D Program of China“the 13th Five-Year Plan”(Grant No.2016YFD0700503)the Science and Technology Project of Shaanxi Province.Also,we thank the critical comments and suggestions from the anonymous reviewers for improving the manuscript.
文摘Axial air-assisted sprayers can distribute pesticides efficiently in kiwifruit orchards.Because of improper parameter settings,most sprayers deliver either too much or too little pesticide.To identify appropriate sprayer parameters for kiwifruit trees,the vertical distribution profiles of the applied liquid spray were examined in this study.The effects of spray fan speed(SFS),spray pressure(SP)and spray distance(SD)on the distributions of the sprayed liquid in the vertical profiles were studied.Combined actions of the above parameters were systematically analysed using the quadratic general rotary design test method.Regression equations for the spray liquid distributions and working factors are presented.Field confirmation experiments were carried out to optimize the parameters.Data analysis showed that the optional sprayer working parameters are those of Group 3,with an SFS equal to 1900 r/min and SP equal to 3.25 MPa.The results of this study provide a reference for future applications of this type of axial air-assisted sprayer in kiwifruit orchards.
基金supported by grants from the National Nature Science Foundation of China(30872666,81172911 and 81271379)Shanghai Key Lab of Forensic Medicine(KF1005)
文摘Objective To systemically explore the range of visual angles that affect visual acuity, and to establish the relationship between the P 1 component (peak latency -100 ms) of the pattern-reversal visual-evoked potential (PRVEP) and the visual acuity at particular visual angles. Methods Two hundred and ten volunteers were divided into seven groups, according to visual acuity as assessed by the standard logarithmic visual acuity chart (SLD-II). For each group, the PRVEP components were elicited in response to visual angle presentations at 8°, 4°, 2°, 1°/60', 30', 15', and 7.5', in the whiteblack chess-board reversal mode with a contrast level of 100% at a frequency of 2 Hz. Visual stimuli were presented monocularly, and 200 presentations were averaged for each block of trials. The early and stable component P1 was recorded at the mid-line of the occipital region (Oz) and analyzed with SPSS 13.00. Results (1) Oz had the maximum Pl amplitude; there was no significant difference between genders or for interocular comparison in normal controls and subjects with optic myopia. (2) The P1 latency decreased slowly below 30', then increased rapidly. The P1 amplitude initially increased with check size, and was maximal at -1° and -30'. (3) The P1 latency in the group with visual acuity 〈0.2 was signifi- cantly different at 8°, 15' and 7.5', while the amplitude differed at all visual angles, compared with the group with normal vision. Differences in P1 for the groups with 0.5 and 0.6 acuity were only present at visual angles 〈1°. (4) Regression analysis showed that the P1 latency and amplitude were associated with visual acuity over the full range of visual angles. There was a moderate correlation at visual angles 〈30'. Regression equations were calculated for the P1 components and visual acuity, based on visual angle. Conclusion (1) Visual angle should be taken into consideration when exploring the function of the visual pathway, especially visual acuity. A visual angle -60' might be appropriate when using PRVEP com- ponents to evaluate poor vision and to identify malingerers. (2) Increased P1 amplitude and decreased P1 latency were as- sociated with increasing visual acuity, and the P1 components displayed a linear correlation with visual acuity, especially in the range of optimal visual angles. Visual acuity can be deduced from P 1 based on visual angle.
文摘The purpose of this study was to develop an equation to predict strength for seven common resistance training exercises using anthropometric and demographic measures.One-hundred forty-seven healthy adults(74 males,73 females,3512 yr,17410 cm,8819 kg)volunteered to participate.Body composition values(regional/total)and body dimensions were assessed using dual-energy x-ray absorptiometry(DEXA).Subjects underwent the following maximal strength assessments:Leg Press,Chest Press,Leg Curl,Lat Pulldown,Leg Extension,Tri-ceps Pushdown,and Biceps Curl.Multiple linear regression with stepwise removal was used to determine the best model to predict maximal strength for each exercise.Independent predictor variables identified(p<0.05)were height(cm);weight(kg);BMI;age;sex(0=F,1=M);regional lean masses(LM,kg);fat mass(FM,kg);fat free mass(FFM,kg);percent fat(%BF);arm,leg,and trunk lengths(AL,LL,TL;cm);and shoulder width(SW,cm).Analyses were performed with and without regional measures to accommodate scenarios where DEXA is un-available.All models presented were significant(p<0.05,R^(2)=0.68-0.83),with regional models producing the greatest accuracy.Results indicate that maximal strength for individual resistance exercises can be reasonably estimated in adults.
文摘Reliable estimation of stature from skeletal remains will continue to play an important role in assessing a variety of forensic anthropological and archaeological issues.In the present study,we studied and collated data on the morphometry of the tibia as well as analyzing its segment that shows significant correlation with its maximum length and consequently formulating linear regression equations for estimating maximum tibia length(MTL)which is specific for the Nigeria population.A total number of 68 intact adult human tibia bones were used(35 right and 33 left).Thirteen anthropometric parameters were measured including the MTL.The mean differences between right and left bones of all the measured parameter were not statistically significant except for the mean shaft circumference.The correlation coefficient between MTL and the bicondylar tibial width(BTW),anterior‑posterior intercondylar diameter(APID),anterior‑posterior diameter of medial condyle(APDMC),midshaft transverse diameter(MSTD),and distal articular surface length(DASL)were seen to be significant(P<0.05)only in the right tibia;therefore,the linear regression equations for estimation of MTL from these parameters for the right tibia were also significant(P<0.05).The results of our study concluded that it is possible to estimate the maximum length of the right tibia from the BTW,APID,APDMC,MSTD,and DASL with relative accuracy.Our study may be useful for forensic investigations for the identification of the remains of unknown bodies in a Nigerian population.