Totally 26 provenance stands of 17-year-old Korean pine were selected for investigating wood properties and growth characters in Mao抏rshan Experimental Forest Farm of Northeast Forestry University in 1999. The anatom...Totally 26 provenance stands of 17-year-old Korean pine were selected for investigating wood properties and growth characters in Mao抏rshan Experimental Forest Farm of Northeast Forestry University in 1999. The anatomical property indexes, including tracheid length, tracheid diameter and wall-indiameter ratio, and the physical property indexes, such as growth ring width, late wood percentage and growth ring density, were measured for wood properties. Growth character indexes, including tree height and diameter at breast height, were also measured. The analytical results showed that there exited obviously dif-ference in wood property indexes between different provenances, which is suggested that wood properties are controlled by their genetic differences. The growth character indexes of Korean pines presented significant difference and they might also be controlled by their genetic differences. Most parameters of wood properties mainly varied in the direction of longitude, but the parameters of growth characters varied in the direction of latitude.展开更多
For the study of main traits of purple-flashed sweetpotato in different soil and ecological environments, 18 cultivars of purple-flashed sweetpotato with different enthocyenin contents were planted at Yancheng and Xuz...For the study of main traits of purple-flashed sweetpotato in different soil and ecological environments, 18 cultivars of purple-flashed sweetpotato with different enthocyenin contents were planted at Yancheng and Xuzhou separately. The main quality traits were determined. The results showed the quality traits of purple-fleshed sweetpotato were significantly influenced by soil and ecological environments. Geno- type (G), environment (E) and genotype x environment (GxE) interaction had signif- icantiy effects on the contents of anthocyanin, dry matter, starch, protein, reducing sugar and soluble sugar in storage roots. Anthocyanin content was most easily af- fected by the environment. The E effect on anthocyanin content was greater than G and GxE effects. However, the GxE interaction effects on other 5 quality traits were greater than G and E effects. The 6 quality traits were significantly different at 1% level under different environments respectively. The contents of dry matter, starch and anthocyenin were higher in Yancheng than in Xuzhou, while the contents of protein, reducing sugar and soluble sugar were higher in Xuzhou. The variation co- efficients of all quality traits at Yancheng and Xuzhou were in the same order: an- sugar〉protein〉starch, the variation coefficient of anthocyanin content was higher in Xuzhou, and the variation coefficients of other 5 traits were higher in Yancheng. Correlation analysis showed that the reducing sugar and solu- ble sugar contents were negatively correlated with starch content, and had no sig- nifiant correlation with anthocyanin and protein contents. Dry matter content and starch content were positively correlated, and anthocyanin content and other quality traits had no significant correlation.展开更多
Influenced by climate, biology and soil properties, vertical soil profile showed stratification character in terms of basic physical properties. The research conducted measurement and analysis on basic physical proper...Influenced by climate, biology and soil properties, vertical soil profile showed stratification character in terms of basic physical properties. The research conducted measurement and analysis on basic physical properties of typical field in the Daxia irrigation area in Qinghai Province. The results showed that soil bulk density changed from decreasing to increasing upon soil horizon; the soil horizons in 0-40 and 90-150 cm were high porosity zones, and the others were low porosi- ty area; the saturation moisture capacity, water retention of capillary porosity and field water retention all changed from decreasing to increasing upon soil horizon featured by arithmetic progression. In addition, the research area in Daxia irrigated area showed loose structure in soil horizon of 0-40 cm, compacted in 40-60 cm, and loose again in 60-200 cm vertically.展开更多
Eight provenances of 19-year-old Picea koraiensis Nakai from the provenancetrials of Maoershan (45°20′N, 127°30′E), Liang-shui (47°10′N, 128°53′E) and Jiagedaqi(50°24′N, 124°07′E) i...Eight provenances of 19-year-old Picea koraiensis Nakai from the provenancetrials of Maoershan (45°20′N, 127°30′E), Liang-shui (47°10′N, 128°53′E) and Jiagedaqi(50°24′N, 124°07′E) in Northeast China were investigated to analyze the genetic variation ingrowth characteristics (tree height and diameter) and wood characteristics (tracheid length,tracheid diameter, tracheid wall thickness, annual ring width as well as wood density). Greatvariation in height growth and breast height diameter growth was observed among the provenances, andalong with the increase of tree age, these provenances presented different geographic adaptability.The growth characteristics of Picea koraiensis stand at age of 10 in Maoershan and Liangshuiprovenance trials had a positive correlation with longitude, and with increase of tree age to 15 and19, the tree growth of the provenances displayed a significant positive correlation with latitudeas well as altitude. For wood characteristics, great variation was also found among the provenances.There exists a close relation between growth characteristics and wood properties of the provenance.The height and breast height diameter growth of the provenance had a positive correlation withtracheid diameter and annual ring width, and a negative correlation with tracheid wall thickness andwood density. Genetic performance of the provenance in all above characteristics was alsoinvestigated in order to provide more useful information for comprehensive selection of this speciesfor pulpwood and plywood production.展开更多
[Objective]The aim was to study the effect of herbicide on the growth of early seedlings of rye(Secale cereale).[Method]Effect of two kinds of herbicide(Atrazine and APM)on seedling growth of rye was investigated ...[Objective]The aim was to study the effect of herbicide on the growth of early seedlings of rye(Secale cereale).[Method]Effect of two kinds of herbicide(Atrazine and APM)on seedling growth of rye was investigated at the physiological,biochemical and cellular level.[Result]The Atrazin significantly decreased the contents of chlorophyll a,b and soluble proteins.Rye seeds were treated with 0.01-1 mg/L Atrazine for 16 h,the contents of chlorophyll a and b decreased from 1.26(a),0.49(b)mg/g FW(control)to 1.15(a),0.46(b)mg/g FW(0.1 mg/L)and 0.81(a),0.33(b)mg/g FW(1.0 mg/L).The content of soluble protein decreased with the increasing concentration of Atrazin.Atrazin had no significant influence on the cell division and chromosome structure variation.The contents of chlorophyll a,b and soluble proteins had no significantly change under the treatment of APM,but the number of chromosome structure variation such as chromosome bridge,multipolar division cells,lagging chromosome and unequal division cells increased significantly.[Conclusion]The critical concentration of Atrazine was 0.1-1.0 mg/L and 4 mg/L of APM in rye.展开更多
Analysis of the spatial variability of soil properties is important to arrange the experimental treatments in the experimental station. This paper aims to study the spatial structure of soil variables and their distri...Analysis of the spatial variability of soil properties is important to arrange the experimental treatments in the experimental station. This paper aims to study the spatial structure of soil variables and their distribution in the Pengshui tobacco experiment station in Chongqing, China. Soil samples were taken from 289 soil points on 20 m grid in March 2012. Twenty-two soil chemical and physical properties were analyzed by classical statistical and geo-statistical methods. Soil pH, cation exchange capacity (CEC), total phosphorus (TP), available phosphorus (AP), zinc (Zn), magnesium (Mg) and sulphur (S) have the strong spatial dependence, with nugget/sill ratios of less than 25%. The others have the moderate dependence with nugget/sill ratios of 26.17% to 71.04%. Ranges of the spatial correlation varied from 51.30 m for chlorine (C1) to 594.90 m for TP. The clearly patchy maps of the nutrients showed the spatial distributions of the soil variables, which can be used for better management of experimental treatments, achieving reliable exoerimental results in the tobacco exnerimental station.Highlight: Scientific experimentation assumes the existence of random variability for soil attributes. This research was to evaluate the spatial variability of soil chemical and physical attributes and to interpolate the spatial distribution of soil properties in the tobacco experimental station in Chongqing. The result of this work can be used for the agricultural management of tobacco cultivation.展开更多
Rocks are heterogeneous from the point of dynamic failure behavior. Both the compressive and microstructure which is of significance to their tensile strength of rock-like materials is regarded different from the stat...Rocks are heterogeneous from the point of dynamic failure behavior. Both the compressive and microstructure which is of significance to their tensile strength of rock-like materials is regarded different from the static strength. The present study adopts smoothed particle hydrodynamics (SPH) which is a virtual particle based meshfree method to investigate strain rate effect for heterogeneous brittle materials. The SPH method is capable of simulating rock fracture, free of the mesh constraint of the traditional FEM and FDM models. A pressure dependent J-H constitutive model involving heterogeneity is employed in the numerical modeling. The results show the compressive strength increases with the increase of strain rate as well as the tensile strength, which is important to the engineering design.展开更多
To explore the spatial heterogeneity of plankton communities in a deep artificial lake (Songhua Lake, China), samples were collected at seven sites. Samples were investigated by denaturing gradient gel electrophores...To explore the spatial heterogeneity of plankton communities in a deep artificial lake (Songhua Lake, China), samples were collected at seven sites. Samples were investigated by denaturing gradient gel electrophoresis (DGGE) analysis of the PCR-amplified 16S and 18S rRNA genes and specific bands were sequenced. Cluster analysis of the DGGE profiles revealed that all of the samples grouped into two distinct clusters, in accordance with sampling site; while in each cluster, the divergence of sub-clusters correlated with sampling depth. Sequence analysis of selected dominant DGGE bands revealed that most sequenced phylotypes (84%) exhibited 〉97% similarity to the closest sequences in GenBank, and were affiliated with ten common freshwater plankton phyla (Proteobacteria, Actinobacteria, Bacteroidetes, Cyanobacteria, Bacillariophyta, Pyrrophyta, Cryptophyta, Ciliophora, Stramenopiles, and Rotifera). Several of these groups are also found worldwide, indicating the cosmopolitan distribution of the phylotypes. The relationships between DGGE patterns and environmental factors were analyzed by redundancy analysis (RDA). The results suggested that, total nitrogen, nitrate, nitrite, temperature were strongly correlated with the variation ammonia, and CODMn concentrations, and water in plankton composition.展开更多
Objective To investigate the mutations of mitochondrial genome in a pedigree with suspected maternally inherited diabetes and deafness and to explore the correlations between the mutations and clinical features. Meth...Objective To investigate the mutations of mitochondrial genome in a pedigree with suspected maternally inherited diabetes and deafness and to explore the correlations between the mutations and clinical features. Methods Genomic DNA was isolated from blood leucocytes of each member of the pedigree. The mitochondrial genome was amplified with 24-pair primers that could cover the entire mitochondrial DNA. Direct sequencing of PCR products was used to identify any mitochondrial DNA mutations. Results Family members on the maternal side all harbored the tRNA^Lcu(UUR) A3243G mutation. The paternal side family members did not have the mutation. The age-of-onset of diabetes of the 4 maternal side family members was 15, 41, 44, and 65 years old, and their corresponding heteroplasmy level of the mutation was 34.5%, 14.9%, 14.6%, and 5.9%, respectively. The age-of-onset of diabetes and heteroplasmy level of A3243G mutation were negatively correlated with a correlation coefficient of -0.980(P=0.02). Meanwhile, patient with high heteroplasmy level of A3243G mutation had relatively low severity of disease. Moreover, 6 reported polymorphisms and 2 new variants were found. Conclusions The main cause of diabetes in this pedigree is the tRNA^Lcu(UUR) A3243G mutation. However, other gene variants may contribute to its pathogenicity. The heteroplasmy level of the tRNA^Lcu(UUR) A3243G mutation is positively associated with earlier age-of-onset and increasing severity of diabetes.展开更多
Xiamen is an economically competitive and highly urbanized city along the coastal area of Fujian Province, China. The research on spatio-temporal variation of landscape heterogeneity under the influence of human activ...Xiamen is an economically competitive and highly urbanized city along the coastal area of Fujian Province, China. The research on spatio-temporal variation of landscape heterogeneity under the influence of human activities is of great importance to the further study on the relationship of landscape pattern and ecological process. It is also crucial to the discovery of spatial variation and intensity distribution of human activities. The research analyzed the intensity of human impacts and the spatial variation features and dynamics of landscape patterns by introducing statistical theories and approaches. We analyzed spatio-temporal variation of landscape heterogeneity using the geostatistical techniques, such as semivariogram and Kriging interpolation.Results show that there is a higher correlation between landscape heterogeneity indexes and human impact index. Both the indexes show a moderate spatial autocorrelation as well as an obvious characteristic of anisotropy. From 1998 to 2008, the spatial differentiation of the changes in the intensity of human activities and the changes in landscape heterogeneity shows that the landscape patterns in Xiamen are closely related with the urban land utilization methods, the condition of traffic and geographical location and the physical geographical condition such as the terrain and the ecological environment. The process of urbanization has a significant impact on the urban landscape pattern.展开更多
Most evaluation of the consistency of multisensor images have focused on Normalized Difference Vegetation Index (NDVI) products for natural landscapes, often neglecting less vegetated urban landscapes. This gap has ...Most evaluation of the consistency of multisensor images have focused on Normalized Difference Vegetation Index (NDVI) products for natural landscapes, often neglecting less vegetated urban landscapes. This gap has been filled through quantifying and evaluating spatial heterogeneity of urban and natural landscapes from QuickBird, Satellite pour l'observation de la Terre (SPOT), Ad- vanced Spacebome Thermal Emission and Reflection Radiometer (ASTER) and Landsat Thematic Mapper (TM) images with variogram analysis. Instead of a logarithmic relationship with pixel size observed in the corresponding aggregated images, the spatial variability decayed and the spatial structures decomposed more slowly and complexly with spatial resolution for real multisensor im- ages. As the spatial resolution increased, the proportion of spatial variability of the smaller spatial structure decreased quickly and only a larger spatial structure was observed at very coarse scales. Compared with visible band, greater spatial variability was observed in near infrared band for both densely and less densely vegetated landscapes. The influence of image size on spatial heterogeneity was highly dependent on whether the empirical sernivariogram reached its sill within the original image size. When the empirical semivariogram did not reach its sill at the original observation scale, spatial variability and mean characteristic length scale would increase with image size; otherwise they might decrease. This study could provide new insights into the knowledge of spatial heterogeneity in real multisen- sor images with consideration of their nominal spatial resolution, image size and spectral bands.展开更多
In the proximity of an active fault, spatial variation of peak ground motion is significantly affected by the faulting mechanism. It has been observed that near fault ground motions consists of different characteristi...In the proximity of an active fault, spatial variation of peak ground motion is significantly affected by the faulting mechanism. It has been observed that near fault ground motions consists of different characteristics compared to the far fault ground motions. Near fault records, in the distance range of less than 100 m from the faults are not available except for few cases. Therefore numerical simulation of ground motions for such near-fault situations is necessary. In addition to the understanding of the phenomenon of near fault ground motion there is a need to enhance our understanding of the possible potential hazard that can be caused due to the future rupture activity by understanding the phenomenon of surface faulting. In this paper we propose numerical simulation based on discrete modeling to investigate the fault rupture propagation and its effect on the surface peak ground acceleration. In the present two dimensional study rupture propagation due to bedrock motion has been observed for different shear wave velocity. A model of size 1000× 150 m is selected for this purpose. It has been observed that as the stiffness of the media is decreasing, the affected surface is decreasing and also width of the shear crack zone is decreasing. Secondly, we attempted to study the ground motion on the surface due to the bedrock motion in presence of boulders in the soil media by keeping the boulder at different positions. We find that there is an increase in the shear zone as well as the PGA on the surface when the boulder is present on the foot wall and in the vicinity of the rupture zone. Finally, we performed the analysis using layered media and studied the affect of crack propagation and also the variation of peak accelerations. Findings from the study can be utilized to assess the damage potential of the near fault areas.展开更多
Triaxial cyclic loading tests have been performed to assess the influence of plastic deformation on inelastic deformational properties of anisotropic argillite with bedding planes which is regarded as a kind of transv...Triaxial cyclic loading tests have been performed to assess the influence of plastic deformation on inelastic deformational properties of anisotropic argillite with bedding planes which is regarded as a kind of transversely isotropic media.Considering argillite's anisotropy and inelastic deformational properties,theoretical formulae for calculating oriented elastic parameters were deduced by the unloading curves,which can be better fitted for the description of its elasticity than loading curves.Test results indicate that with the growth of accumulated plastic,strain,the apparent elastic modulus of argillite decreases in a form of exponential decay function,whereas the apparent Poisson ratio increase in a form of power equation.A ratio of unloading recoverable strain to the total strain increment occurred during a loading cycle is defined to illustrate the characteristic relations between anisotropic coupled elasto-plastic deformation and plastic strain.It is significant to observe that high stress level and plastic history have an inhibiting effect on argillite anisotropy.展开更多
Slow trends in the RR interval(RRI) series should be removed in the preprocessing step to get a reliable result of heart rate variability(HRV) analysis. Re-sampling is required to convert the unevenly sampled RRI seri...Slow trends in the RR interval(RRI) series should be removed in the preprocessing step to get a reliable result of heart rate variability(HRV) analysis. Re-sampling is required to convert the unevenly sampled RRI series into evenly sampled time series when using the widely accepted smoothness priors approach(SPA). Noise is introduced in this process and the information quality is thus compromised. Empirical mode decomposition(EMD) and its variants, were introduced to directly process the unevenly sampled RRI series. Besides, a RR interval model was proposed to fascinate the introduction of standard metrics for the evaluation of the detrending performance. Based on standard metrics including signal-to-noise-ratio in d B(ISNR), mean square error(EMS), and percent root square difference(DPRS), the effectiveness of detrending methods in RR interval analysis were determined. Results demonstrate that complementary ensemble EMD(CEEMD, a variant of EMD) based method has a higher ISNR, a lower EMS and a lower DPRS as well as a better RRI series detrending performance compared with the SPA method, which would in turn lead to a more accurate HRV analysis.展开更多
The impact of temporal variation of rainfall on the relationship between rainfall and catchment response is investigated in a catchment with high temporally variable rainfalls and a high percentage of permeable soils ...The impact of temporal variation of rainfall on the relationship between rainfall and catchment response is investigated in a catchment with high temporally variable rainfalls and a high percentage of permeable soils in the southwest of Iran.Twenty-nine storm events are classified into two classes, High Temporal heterogeneous(HT) and Low Temporal heterogeneous(LT) events using the variogram technique and the storm events of each class are analyzed to detect the relationship between Curve Number(CN) and rainfall depth. It is found that there is not a similar correlation between CN values and rainfall depths for both temporally variable classes, and hence, two different responses can be observed in the catchment according to rainfall temporal heterogeneities. For HT events, a complacent behavior is detected in which the CNs decline as rainfall depth increases while a different response, violent behavior, is observed for LT events in which the CNs rise and asymptotically approach a constant value with increasing storm size. This considerable difference between CN-P relationships derived from the two temporally variable classes of rainfall is attributed to the provocation of different runoff generation mechanisms, infiltration-excess and saturation-excess caused by rainfall temporal heterogeneities. Moreover, the results support the validity of variogram technique to classify storm events into two LT and HT classes.展开更多
As the offshore engineering moving from shallow to deep waters, the foundation types for fixed and floating platforms have been gradually evolving to minimize engineering costs and structural risks in the harsh offsho...As the offshore engineering moving from shallow to deep waters, the foundation types for fixed and floating platforms have been gradually evolving to minimize engineering costs and structural risks in the harsh offshore environments. Particular focus of this paper is on the foundation instability and its failure mechanisms as well as the relevant theory advances for the prevailing foundation types in both shallow and deep water depths. Piles, spudcans, gravity bases, suction caissons, and plate anchors are detailed in this paper. The failure phenomena and mechanisms for each type of foundations are identified and summarized, respectively. The theoretical approaches along with sophisticated empirical solutions for the bearing capacity problems are then presented. The major challenges are from flow-structure-soil coupling processes, rigorous constitutive modeling of cyclic behaviors of marine sediments, and the spatial variability of soil properties for large-spreading structures. Further researches are suggested to reveal the instability mechanisms for underpinning the evolution of offshore foundations.展开更多
文摘Totally 26 provenance stands of 17-year-old Korean pine were selected for investigating wood properties and growth characters in Mao抏rshan Experimental Forest Farm of Northeast Forestry University in 1999. The anatomical property indexes, including tracheid length, tracheid diameter and wall-indiameter ratio, and the physical property indexes, such as growth ring width, late wood percentage and growth ring density, were measured for wood properties. Growth character indexes, including tree height and diameter at breast height, were also measured. The analytical results showed that there exited obviously dif-ference in wood property indexes between different provenances, which is suggested that wood properties are controlled by their genetic differences. The growth character indexes of Korean pines presented significant difference and they might also be controlled by their genetic differences. Most parameters of wood properties mainly varied in the direction of longitude, but the parameters of growth characters varied in the direction of latitude.
基金Supported by Earmarked Fund for China Agriculture Research System(CARS-11,sweetpotato)Jiangsu Science and Technology Support Program(BE2014315)+1 种基金Jiangsu Agricultural Science and Technology Independent Innovation Fund(CX(13)2032)Jiangsu Key Research and Development Program(modern agriculture)(BE2015313)~~
文摘For the study of main traits of purple-flashed sweetpotato in different soil and ecological environments, 18 cultivars of purple-flashed sweetpotato with different enthocyenin contents were planted at Yancheng and Xuzhou separately. The main quality traits were determined. The results showed the quality traits of purple-fleshed sweetpotato were significantly influenced by soil and ecological environments. Geno- type (G), environment (E) and genotype x environment (GxE) interaction had signif- icantiy effects on the contents of anthocyanin, dry matter, starch, protein, reducing sugar and soluble sugar in storage roots. Anthocyanin content was most easily af- fected by the environment. The E effect on anthocyanin content was greater than G and GxE effects. However, the GxE interaction effects on other 5 quality traits were greater than G and E effects. The 6 quality traits were significantly different at 1% level under different environments respectively. The contents of dry matter, starch and anthocyenin were higher in Yancheng than in Xuzhou, while the contents of protein, reducing sugar and soluble sugar were higher in Xuzhou. The variation co- efficients of all quality traits at Yancheng and Xuzhou were in the same order: an- sugar〉protein〉starch, the variation coefficient of anthocyanin content was higher in Xuzhou, and the variation coefficients of other 5 traits were higher in Yancheng. Correlation analysis showed that the reducing sugar and solu- ble sugar contents were negatively correlated with starch content, and had no sig- nifiant correlation with anthocyanin and protein contents. Dry matter content and starch content were positively correlated, and anthocyanin content and other quality traits had no significant correlation.
基金Supported by Water Consumption Coefficient in the Yellow River Basin in Qinghai Province(QX2012-019)~~
文摘Influenced by climate, biology and soil properties, vertical soil profile showed stratification character in terms of basic physical properties. The research conducted measurement and analysis on basic physical properties of typical field in the Daxia irrigation area in Qinghai Province. The results showed that soil bulk density changed from decreasing to increasing upon soil horizon; the soil horizons in 0-40 and 90-150 cm were high porosity zones, and the others were low porosi- ty area; the saturation moisture capacity, water retention of capillary porosity and field water retention all changed from decreasing to increasing upon soil horizon featured by arithmetic progression. In addition, the research area in Daxia irrigated area showed loose structure in soil horizon of 0-40 cm, compacted in 40-60 cm, and loose again in 60-200 cm vertically.
基金The paper was supported by National Key Project of The State Forestry Administration.( 96-011-01-06)
文摘Eight provenances of 19-year-old Picea koraiensis Nakai from the provenancetrials of Maoershan (45°20′N, 127°30′E), Liang-shui (47°10′N, 128°53′E) and Jiagedaqi(50°24′N, 124°07′E) in Northeast China were investigated to analyze the genetic variation ingrowth characteristics (tree height and diameter) and wood characteristics (tracheid length,tracheid diameter, tracheid wall thickness, annual ring width as well as wood density). Greatvariation in height growth and breast height diameter growth was observed among the provenances, andalong with the increase of tree age, these provenances presented different geographic adaptability.The growth characteristics of Picea koraiensis stand at age of 10 in Maoershan and Liangshuiprovenance trials had a positive correlation with longitude, and with increase of tree age to 15 and19, the tree growth of the provenances displayed a significant positive correlation with latitudeas well as altitude. For wood characteristics, great variation was also found among the provenances.There exists a close relation between growth characteristics and wood properties of the provenance.The height and breast height diameter growth of the provenance had a positive correlation withtracheid diameter and annual ring width, and a negative correlation with tracheid wall thickness andwood density. Genetic performance of the provenance in all above characteristics was alsoinvestigated in order to provide more useful information for comprehensive selection of this speciesfor pulpwood and plywood production.
基金Supported by Key Project for Science Researches of Ministry of Education(02010)~~
文摘[Objective]The aim was to study the effect of herbicide on the growth of early seedlings of rye(Secale cereale).[Method]Effect of two kinds of herbicide(Atrazine and APM)on seedling growth of rye was investigated at the physiological,biochemical and cellular level.[Result]The Atrazin significantly decreased the contents of chlorophyll a,b and soluble proteins.Rye seeds were treated with 0.01-1 mg/L Atrazine for 16 h,the contents of chlorophyll a and b decreased from 1.26(a),0.49(b)mg/g FW(control)to 1.15(a),0.46(b)mg/g FW(0.1 mg/L)and 0.81(a),0.33(b)mg/g FW(1.0 mg/L).The content of soluble protein decreased with the increasing concentration of Atrazin.Atrazin had no significant influence on the cell division and chromosome structure variation.The contents of chlorophyll a,b and soluble proteins had no significantly change under the treatment of APM,but the number of chromosome structure variation such as chromosome bridge,multipolar division cells,lagging chromosome and unequal division cells increased significantly.[Conclusion]The critical concentration of Atrazine was 0.1-1.0 mg/L and 4 mg/L of APM in rye.
文摘Analysis of the spatial variability of soil properties is important to arrange the experimental treatments in the experimental station. This paper aims to study the spatial structure of soil variables and their distribution in the Pengshui tobacco experiment station in Chongqing, China. Soil samples were taken from 289 soil points on 20 m grid in March 2012. Twenty-two soil chemical and physical properties were analyzed by classical statistical and geo-statistical methods. Soil pH, cation exchange capacity (CEC), total phosphorus (TP), available phosphorus (AP), zinc (Zn), magnesium (Mg) and sulphur (S) have the strong spatial dependence, with nugget/sill ratios of less than 25%. The others have the moderate dependence with nugget/sill ratios of 26.17% to 71.04%. Ranges of the spatial correlation varied from 51.30 m for chlorine (C1) to 594.90 m for TP. The clearly patchy maps of the nutrients showed the spatial distributions of the soil variables, which can be used for better management of experimental treatments, achieving reliable exoerimental results in the tobacco exnerimental station.Highlight: Scientific experimentation assumes the existence of random variability for soil attributes. This research was to evaluate the spatial variability of soil chemical and physical attributes and to interpolate the spatial distribution of soil properties in the tobacco experimental station in Chongqing. The result of this work can be used for the agricultural management of tobacco cultivation.
文摘Rocks are heterogeneous from the point of dynamic failure behavior. Both the compressive and microstructure which is of significance to their tensile strength of rock-like materials is regarded different from the static strength. The present study adopts smoothed particle hydrodynamics (SPH) which is a virtual particle based meshfree method to investigate strain rate effect for heterogeneous brittle materials. The SPH method is capable of simulating rock fracture, free of the mesh constraint of the traditional FEM and FDM models. A pressure dependent J-H constitutive model involving heterogeneity is employed in the numerical modeling. The results show the compressive strength increases with the increase of strain rate as well as the tensile strength, which is important to the engineering design.
基金Supported by the National Natural Science Foundation of China(No.51178090)the National Key Technology R&D Program of China(No.2012BAJ21B02-02)the National Water Pollution Control and Management Technology Major Projects(No.2009ZX07106-001)
文摘To explore the spatial heterogeneity of plankton communities in a deep artificial lake (Songhua Lake, China), samples were collected at seven sites. Samples were investigated by denaturing gradient gel electrophoresis (DGGE) analysis of the PCR-amplified 16S and 18S rRNA genes and specific bands were sequenced. Cluster analysis of the DGGE profiles revealed that all of the samples grouped into two distinct clusters, in accordance with sampling site; while in each cluster, the divergence of sub-clusters correlated with sampling depth. Sequence analysis of selected dominant DGGE bands revealed that most sequenced phylotypes (84%) exhibited 〉97% similarity to the closest sequences in GenBank, and were affiliated with ten common freshwater plankton phyla (Proteobacteria, Actinobacteria, Bacteroidetes, Cyanobacteria, Bacillariophyta, Pyrrophyta, Cryptophyta, Ciliophora, Stramenopiles, and Rotifera). Several of these groups are also found worldwide, indicating the cosmopolitan distribution of the phylotypes. The relationships between DGGE patterns and environmental factors were analyzed by redundancy analysis (RDA). The results suggested that, total nitrogen, nitrate, nitrite, temperature were strongly correlated with the variation ammonia, and CODMn concentrations, and water in plankton composition.
文摘Objective To investigate the mutations of mitochondrial genome in a pedigree with suspected maternally inherited diabetes and deafness and to explore the correlations between the mutations and clinical features. Methods Genomic DNA was isolated from blood leucocytes of each member of the pedigree. The mitochondrial genome was amplified with 24-pair primers that could cover the entire mitochondrial DNA. Direct sequencing of PCR products was used to identify any mitochondrial DNA mutations. Results Family members on the maternal side all harbored the tRNA^Lcu(UUR) A3243G mutation. The paternal side family members did not have the mutation. The age-of-onset of diabetes of the 4 maternal side family members was 15, 41, 44, and 65 years old, and their corresponding heteroplasmy level of the mutation was 34.5%, 14.9%, 14.6%, and 5.9%, respectively. The age-of-onset of diabetes and heteroplasmy level of A3243G mutation were negatively correlated with a correlation coefficient of -0.980(P=0.02). Meanwhile, patient with high heteroplasmy level of A3243G mutation had relatively low severity of disease. Moreover, 6 reported polymorphisms and 2 new variants were found. Conclusions The main cause of diabetes in this pedigree is the tRNA^Lcu(UUR) A3243G mutation. However, other gene variants may contribute to its pathogenicity. The heteroplasmy level of the tRNA^Lcu(UUR) A3243G mutation is positively associated with earlier age-of-onset and increasing severity of diabetes.
基金Under the auspices of National 'Eleventh Five-Year Plan' Science and Technology Support Project (No. 2009BADB2B0302)Science and Technology Major Project of Fujian Province,the European Union Seventh Framework Project (No. 247608)
文摘Xiamen is an economically competitive and highly urbanized city along the coastal area of Fujian Province, China. The research on spatio-temporal variation of landscape heterogeneity under the influence of human activities is of great importance to the further study on the relationship of landscape pattern and ecological process. It is also crucial to the discovery of spatial variation and intensity distribution of human activities. The research analyzed the intensity of human impacts and the spatial variation features and dynamics of landscape patterns by introducing statistical theories and approaches. We analyzed spatio-temporal variation of landscape heterogeneity using the geostatistical techniques, such as semivariogram and Kriging interpolation.Results show that there is a higher correlation between landscape heterogeneity indexes and human impact index. Both the indexes show a moderate spatial autocorrelation as well as an obvious characteristic of anisotropy. From 1998 to 2008, the spatial differentiation of the changes in the intensity of human activities and the changes in landscape heterogeneity shows that the landscape patterns in Xiamen are closely related with the urban land utilization methods, the condition of traffic and geographical location and the physical geographical condition such as the terrain and the ecological environment. The process of urbanization has a significant impact on the urban landscape pattern.
基金Under the auspices of National Natural Science Foundation of China(No.41071267,41001254)Natural Science Foundation of Fujian Province(No.2012I0005,2012J01167)
文摘Most evaluation of the consistency of multisensor images have focused on Normalized Difference Vegetation Index (NDVI) products for natural landscapes, often neglecting less vegetated urban landscapes. This gap has been filled through quantifying and evaluating spatial heterogeneity of urban and natural landscapes from QuickBird, Satellite pour l'observation de la Terre (SPOT), Ad- vanced Spacebome Thermal Emission and Reflection Radiometer (ASTER) and Landsat Thematic Mapper (TM) images with variogram analysis. Instead of a logarithmic relationship with pixel size observed in the corresponding aggregated images, the spatial variability decayed and the spatial structures decomposed more slowly and complexly with spatial resolution for real multisensor im- ages. As the spatial resolution increased, the proportion of spatial variability of the smaller spatial structure decreased quickly and only a larger spatial structure was observed at very coarse scales. Compared with visible band, greater spatial variability was observed in near infrared band for both densely and less densely vegetated landscapes. The influence of image size on spatial heterogeneity was highly dependent on whether the empirical sernivariogram reached its sill within the original image size. When the empirical semivariogram did not reach its sill at the original observation scale, spatial variability and mean characteristic length scale would increase with image size; otherwise they might decrease. This study could provide new insights into the knowledge of spatial heterogeneity in real multisen- sor images with consideration of their nominal spatial resolution, image size and spectral bands.
文摘In the proximity of an active fault, spatial variation of peak ground motion is significantly affected by the faulting mechanism. It has been observed that near fault ground motions consists of different characteristics compared to the far fault ground motions. Near fault records, in the distance range of less than 100 m from the faults are not available except for few cases. Therefore numerical simulation of ground motions for such near-fault situations is necessary. In addition to the understanding of the phenomenon of near fault ground motion there is a need to enhance our understanding of the possible potential hazard that can be caused due to the future rupture activity by understanding the phenomenon of surface faulting. In this paper we propose numerical simulation based on discrete modeling to investigate the fault rupture propagation and its effect on the surface peak ground acceleration. In the present two dimensional study rupture propagation due to bedrock motion has been observed for different shear wave velocity. A model of size 1000× 150 m is selected for this purpose. It has been observed that as the stiffness of the media is decreasing, the affected surface is decreasing and also width of the shear crack zone is decreasing. Secondly, we attempted to study the ground motion on the surface due to the bedrock motion in presence of boulders in the soil media by keeping the boulder at different positions. We find that there is an increase in the shear zone as well as the PGA on the surface when the boulder is present on the foot wall and in the vicinity of the rupture zone. Finally, we performed the analysis using layered media and studied the affect of crack propagation and also the variation of peak accelerations. Findings from the study can be utilized to assess the damage potential of the near fault areas.
基金Program(2011CB710601) supported by National Basic Research Program of ChinaProject(50925933) supported by National Natural Science Foundation of China+1 种基金Project(2008BAB29B03) supported by National Key Technology Research and Development Program of ChinaProject(2010-122-011) supported by Guizhou Provincial Department of Transportation,China
文摘Triaxial cyclic loading tests have been performed to assess the influence of plastic deformation on inelastic deformational properties of anisotropic argillite with bedding planes which is regarded as a kind of transversely isotropic media.Considering argillite's anisotropy and inelastic deformational properties,theoretical formulae for calculating oriented elastic parameters were deduced by the unloading curves,which can be better fitted for the description of its elasticity than loading curves.Test results indicate that with the growth of accumulated plastic,strain,the apparent elastic modulus of argillite decreases in a form of exponential decay function,whereas the apparent Poisson ratio increase in a form of power equation.A ratio of unloading recoverable strain to the total strain increment occurred during a loading cycle is defined to illustrate the characteristic relations between anisotropic coupled elasto-plastic deformation and plastic strain.It is significant to observe that high stress level and plastic history have an inhibiting effect on argillite anisotropy.
基金Project(41227803)supported by the National Natural Science Foundation of ChinaProject(KF11011)supported by the State Key Laboratory of Automotive Safety and Energy(Tsinghua University),ChinaProject(DTNH22-08-C-00082)supported by the National Highway Traffic Safety Administration,USA
文摘Slow trends in the RR interval(RRI) series should be removed in the preprocessing step to get a reliable result of heart rate variability(HRV) analysis. Re-sampling is required to convert the unevenly sampled RRI series into evenly sampled time series when using the widely accepted smoothness priors approach(SPA). Noise is introduced in this process and the information quality is thus compromised. Empirical mode decomposition(EMD) and its variants, were introduced to directly process the unevenly sampled RRI series. Besides, a RR interval model was proposed to fascinate the introduction of standard metrics for the evaluation of the detrending performance. Based on standard metrics including signal-to-noise-ratio in d B(ISNR), mean square error(EMS), and percent root square difference(DPRS), the effectiveness of detrending methods in RR interval analysis were determined. Results demonstrate that complementary ensemble EMD(CEEMD, a variant of EMD) based method has a higher ISNR, a lower EMS and a lower DPRS as well as a better RRI series detrending performance compared with the SPA method, which would in turn lead to a more accurate HRV analysis.
文摘The impact of temporal variation of rainfall on the relationship between rainfall and catchment response is investigated in a catchment with high temporally variable rainfalls and a high percentage of permeable soils in the southwest of Iran.Twenty-nine storm events are classified into two classes, High Temporal heterogeneous(HT) and Low Temporal heterogeneous(LT) events using the variogram technique and the storm events of each class are analyzed to detect the relationship between Curve Number(CN) and rainfall depth. It is found that there is not a similar correlation between CN values and rainfall depths for both temporally variable classes, and hence, two different responses can be observed in the catchment according to rainfall temporal heterogeneities. For HT events, a complacent behavior is detected in which the CNs decline as rainfall depth increases while a different response, violent behavior, is observed for LT events in which the CNs rise and asymptotically approach a constant value with increasing storm size. This considerable difference between CN-P relationships derived from the two temporally variable classes of rainfall is attributed to the provocation of different runoff generation mechanisms, infiltration-excess and saturation-excess caused by rainfall temporal heterogeneities. Moreover, the results support the validity of variogram technique to classify storm events into two LT and HT classes.
基金supported by the National Natural Science Foundation of China(Grant Nos.11232012,11372319 and 51309213)the National Key Basic Research Program of China(Grant No.2014CB046204)
文摘As the offshore engineering moving from shallow to deep waters, the foundation types for fixed and floating platforms have been gradually evolving to minimize engineering costs and structural risks in the harsh offshore environments. Particular focus of this paper is on the foundation instability and its failure mechanisms as well as the relevant theory advances for the prevailing foundation types in both shallow and deep water depths. Piles, spudcans, gravity bases, suction caissons, and plate anchors are detailed in this paper. The failure phenomena and mechanisms for each type of foundations are identified and summarized, respectively. The theoretical approaches along with sophisticated empirical solutions for the bearing capacity problems are then presented. The major challenges are from flow-structure-soil coupling processes, rigorous constitutive modeling of cyclic behaviors of marine sediments, and the spatial variability of soil properties for large-spreading structures. Further researches are suggested to reveal the instability mechanisms for underpinning the evolution of offshore foundations.