Seasonal variations in the phytoplankton community and the relationship between environmental factors of the sea area around Xiaoheishan Island are investigated in the present study. Xiaoheishan Island is located at 3...Seasonal variations in the phytoplankton community and the relationship between environmental factors of the sea area around Xiaoheishan Island are investigated in the present study. Xiaoheishan Island is located at 37°58′14″N and 120°38′46″E in Shandong Province, China. A total of 65 species of phytoplankton belonging to three phyla and 27 genera were identified, with Bacillariophyta having the largest number of species. The annual average chlorophyll a concentration for this area was 3.11 μg/L, and there occurs a Skeletonema costatum bloom in winter. The Shannon-Weaver indexes(log_2) of the phytoplankton from all stations were higher than 1, and the Pielou indexes were all higher than 0.3. The results of the canonical correspondence analysis(CCA) indicated that water temperature, PO_4^(3ˉ) and Cu were the environmental factors that had the greatest influence on the distribution of the phytoplankton community throughout the entire year. Although the concentration of heavy metal is well up to the state standards of the first grade of China(GB 3097-1997), these metals still have an impact on the phytoplankton community from this area.展开更多
Introducing a combination of transcription factors such as Oct4,Sox2,Klf4 and c-Myc（OSKM）enables reprogramming which converts somatic cells into induced pluripotent stem cells（i PSCs）（Takahashi and Yamanaka,2006...Introducing a combination of transcription factors such as Oct4,Sox2,Klf4 and c-Myc（OSKM）enables reprogramming which converts somatic cells into induced pluripotent stem cells（i PSCs）（Takahashi and Yamanaka,2006）.i PSCs play an important role in clinical and regenerative medicine because they can be utilized to model a specific disease or differentiate into functional cells for transplantation.Enhancing the efficiency of induction and improving the qualities of iPSCs are constant themes in this field.展开更多
Few studies have been carried out to date on the influence of bacteria on variations in the abiotic properties of water. The aim of the present work was to evaluate the influence of Escherichia coli and Aeromonas hydr...Few studies have been carried out to date on the influence of bacteria on variations in the abiotic properties of water. The aim of the present work was to evaluate the influence of Escherichia coli and Aeromonas hydrophila on some abiotic properties of groundwater stored under aerobic or anaerobic conditions. Experiments were performed in the presence of monospecific cells and bispecific cells. The incubation temperatures were 4˚C and 23˚C. The incubation (storage) times were 6 h, 12 h, 24 h, 48 h and 72 h. Bacteriological analyses were carried out using culture and physicochemical analyses using appropriate techniques. The results show that in the presence of monospecific cells and under aerobic conditions, E. coli abundances were relatively lower than under anaerobic conditions. The opposite was observed in the presence of bispecific cells. In most cases, minimum cell abundances were observed after 6 hours of storage. The same was true for A. hydrophila cells. The values of pH, electrical conductivity and ammonium ions in the water on the day of sampling varied over time. The pH values were relatively higher at 4˚C in the presence of E. coli cells alone, and at 23˚C in the presence of A. hydrophila cells. Ammonium ion levels were relatively higher at 4˚C under anaerobic conditions for both bacterial species. The highest electrical conductivity value was observed at 23˚C in the presence of E. coli cells, and at 4˚C in the presence of A. hydrophila cells, under anaerobic conditions. Electrical conductivity is higher in the presence of A. hydrophila with fluctuations from 169 to 285 µS/cm after 24 h incubation and 259 µS/cm after 6 hours incubation at 4˚C and 23˚C respectively. Under anaerobic conditions and in the presence of E. coli, the conductivity varied from 169 µS/cm at sampling to 274 µS/cm after 72 hours of incubation at 4˚C and from 169 to 289 after 24 hours. Under the same experimental conditions and in the presence of A. hydrophila, the electrical conductivity is higher at 4˚C with a value of 299 µS/cm after 24 hours. In the monospecific condition and under aerobic and anaerobic conditions and at an incubation temperature of 4˚C, the increase in the abundance of E. coli cells is significantly and positively correlated with the increase in pH values. In the mixed condition, pH is very significantly and positively correlated with the abundance of commensal Escherichia coli in anaerobic conditions (P NH4+) is significantly and negatively correlated with cellular concentrations of A. hydrophila in both aerobic and anaerobic conditions.展开更多
The mixture of factor analyzers （MFA） can accurately describe high resolution range profile （HRRP） statistical charac- teristics. But how to determine the proper number of the models is a problem. This paper devel...The mixture of factor analyzers （MFA） can accurately describe high resolution range profile （HRRP） statistical charac- teristics. But how to determine the proper number of the models is a problem. This paper develops a variational Bayesian mixture of factor analyzers （VBMFA） model. This procedure can obtain a lower bound on the Bayesian integral using the Jensen＇s inequality. An analytical solution of the Bayesian integral could be obtained by a hypothesis that latent variables in the model are indepen- dent. During computing the parameters of the model, birth-death moves are utilized to determine the optimal number of model au- tomatically. Experimental results for measured data show that the VBMFA method has better recognition performance than FA and MFA method.展开更多
Based on the completely parametric crystal-field model, the energy level parameters, including free-ion parameters and crystal-field parameters, obtained by fitting the experimental energy level data sets of Ln^（3＋...Based on the completely parametric crystal-field model, the energy level parameters, including free-ion parameters and crystal-field parameters, obtained by fitting the experimental energy level data sets of Ln^（3＋） in LiYF_4 were systematically analyzed. The results revealed that the regular variation trends of the major parameters at relatively low site symmetry still existed. The g factors of ground states were calculated using the parameters obtained from least-squares fitting. The results for Ce^（3＋）, Nd^（3＋）, Sm^（3＋）, Dy^（3＋） and Yb^（3＋） were in good agreement with experiment, while those of Er^（3＋） deviated from experiment dramatically. Further study showed that the g factors depended strongly on B_4~6, and a slightly different B_4~6 value of -580cm^（-1） led to g factors agreeing well with the experimental values.展开更多
基金Supported by the National Natural Science Foundation of China(NSFC)(No.41206102)the National Marine Public Welfare Research Project(No.201305009)the NSFC-Shandong Joint Fund(No.U1406403)
文摘Seasonal variations in the phytoplankton community and the relationship between environmental factors of the sea area around Xiaoheishan Island are investigated in the present study. Xiaoheishan Island is located at 37°58′14″N and 120°38′46″E in Shandong Province, China. A total of 65 species of phytoplankton belonging to three phyla and 27 genera were identified, with Bacillariophyta having the largest number of species. The annual average chlorophyll a concentration for this area was 3.11 μg/L, and there occurs a Skeletonema costatum bloom in winter. The Shannon-Weaver indexes(log_2) of the phytoplankton from all stations were higher than 1, and the Pielou indexes were all higher than 0.3. The results of the canonical correspondence analysis(CCA) indicated that water temperature, PO_4^(3ˉ) and Cu were the environmental factors that had the greatest influence on the distribution of the phytoplankton community throughout the entire year. Although the concentration of heavy metal is well up to the state standards of the first grade of China(GB 3097-1997), these metals still have an impact on the phytoplankton community from this area.
基金supported by the Strategic Priority Research Program of Chinese Academy of Sciences (No. XDA01020102)the grant from the Natural Science Foundation of China (No. 81225004)
文摘Introducing a combination of transcription factors such as Oct4,Sox2,Klf4 and c-Myc（OSKM）enables reprogramming which converts somatic cells into induced pluripotent stem cells（i PSCs）（Takahashi and Yamanaka,2006）.i PSCs play an important role in clinical and regenerative medicine because they can be utilized to model a specific disease or differentiate into functional cells for transplantation.Enhancing the efficiency of induction and improving the qualities of iPSCs are constant themes in this field.
文摘Few studies have been carried out to date on the influence of bacteria on variations in the abiotic properties of water. The aim of the present work was to evaluate the influence of Escherichia coli and Aeromonas hydrophila on some abiotic properties of groundwater stored under aerobic or anaerobic conditions. Experiments were performed in the presence of monospecific cells and bispecific cells. The incubation temperatures were 4˚C and 23˚C. The incubation (storage) times were 6 h, 12 h, 24 h, 48 h and 72 h. Bacteriological analyses were carried out using culture and physicochemical analyses using appropriate techniques. The results show that in the presence of monospecific cells and under aerobic conditions, E. coli abundances were relatively lower than under anaerobic conditions. The opposite was observed in the presence of bispecific cells. In most cases, minimum cell abundances were observed after 6 hours of storage. The same was true for A. hydrophila cells. The values of pH, electrical conductivity and ammonium ions in the water on the day of sampling varied over time. The pH values were relatively higher at 4˚C in the presence of E. coli cells alone, and at 23˚C in the presence of A. hydrophila cells. Ammonium ion levels were relatively higher at 4˚C under anaerobic conditions for both bacterial species. The highest electrical conductivity value was observed at 23˚C in the presence of E. coli cells, and at 4˚C in the presence of A. hydrophila cells, under anaerobic conditions. Electrical conductivity is higher in the presence of A. hydrophila with fluctuations from 169 to 285 µS/cm after 24 h incubation and 259 µS/cm after 6 hours incubation at 4˚C and 23˚C respectively. Under anaerobic conditions and in the presence of E. coli, the conductivity varied from 169 µS/cm at sampling to 274 µS/cm after 72 hours of incubation at 4˚C and from 169 to 289 after 24 hours. Under the same experimental conditions and in the presence of A. hydrophila, the electrical conductivity is higher at 4˚C with a value of 299 µS/cm after 24 hours. In the monospecific condition and under aerobic and anaerobic conditions and at an incubation temperature of 4˚C, the increase in the abundance of E. coli cells is significantly and positively correlated with the increase in pH values. In the mixed condition, pH is very significantly and positively correlated with the abundance of commensal Escherichia coli in anaerobic conditions (P NH4+) is significantly and negatively correlated with cellular concentrations of A. hydrophila in both aerobic and anaerobic conditions.
基金supported in part by the National Natural Science Foundation of China(60772140)the Program for Cheung Kong Scholarsand Innovative Research Team in University(IRT0645)
文摘The mixture of factor analyzers （MFA） can accurately describe high resolution range profile （HRRP） statistical charac- teristics. But how to determine the proper number of the models is a problem. This paper develops a variational Bayesian mixture of factor analyzers （VBMFA） model. This procedure can obtain a lower bound on the Bayesian integral using the Jensen＇s inequality. An analytical solution of the Bayesian integral could be obtained by a hypothesis that latent variables in the model are indepen- dent. During computing the parameters of the model, birth-death moves are utilized to determine the optimal number of model au- tomatically. Experimental results for measured data show that the VBMFA method has better recognition performance than FA and MFA method.
基金Project supported by the National Key Basic Research Program of China(2013CB921800)the National Natural Science Foundation of China(11274299,11374291,11574298,11204292,11404321)the Anhui Provincial Natural Science Foundation(1308085QE75)
文摘Based on the completely parametric crystal-field model, the energy level parameters, including free-ion parameters and crystal-field parameters, obtained by fitting the experimental energy level data sets of Ln^（3＋） in LiYF_4 were systematically analyzed. The results revealed that the regular variation trends of the major parameters at relatively low site symmetry still existed. The g factors of ground states were calculated using the parameters obtained from least-squares fitting. The results for Ce^（3＋）, Nd^（3＋）, Sm^（3＋）, Dy^（3＋） and Yb^（3＋） were in good agreement with experiment, while those of Er^（3＋） deviated from experiment dramatically. Further study showed that the g factors depended strongly on B_4~6, and a slightly different B_4~6 value of -580cm^（-1） led to g factors agreeing well with the experimental values.
