Based on the data of phytoplankton concentration and environmental factors in Bohai Bay from May to September in 2003. the relationship between environmental factors and phytoplankton biomass was analyzed. By analysis...Based on the data of phytoplankton concentration and environmental factors in Bohai Bay from May to September in 2003. the relationship between environmental factors and phytoplankton biomass was analyzed. By analysis of variance, the weather condition was found to have no direct relation with phytoplankton biomass. Correlation coefficients showed that temperature, pH value,the concentrations of silicate and nitrate exhibited linear relationship with phytoplankton biomass.With principal component analysis, pollution types which affected the abundance of phytoplankton included point sources such as municipal and industrial effluents, agricultural runoff and earth's surface water. Using multivariate stepwise regression method and taking the correlation analysis results into consideration, a multi-step regression equation was developed to predict the concentration of phytoplankton in September 2003. Combined results show that temperature, pH value, the concentrations of silicate and nitrate are the critical ecological factors affecting the phytoplankton biomass in Bohai Bay.展开更多
Multivariate statistical techniques,such as cluster analysis(CA),discriminant analysis(DA),principal component analysis(PCA) and factor analysis(FA),were applied to evaluate and interpret the surface water quality dat...Multivariate statistical techniques,such as cluster analysis(CA),discriminant analysis(DA),principal component analysis(PCA) and factor analysis(FA),were applied to evaluate and interpret the surface water quality data sets of the Second Songhua River(SSHR) basin in China,obtained during two years(2012-2013) of monitoring of 10 physicochemical parameters at 15 different sites.The results showed that most of physicochemical parameters varied significantly among the sampling sites.Three significant groups,highly polluted(HP),moderately polluted(MP) and less polluted(LP),of sampling sites were obtained through Hierarchical agglomerative CA on the basis of similarity of water quality characteristics.DA identified p H,F,DO,NH3-N,COD and VPhs were the most important parameters contributing to spatial variations of surface water quality.However,DA did not give a considerable data reduction(40% reduction).PCA/FA resulted in three,three and four latent factors explaining 70%,62% and 71% of the total variance in water quality data sets of HP,MP and LP regions,respectively.FA revealed that the SSHR water chemistry was strongly affected by anthropogenic activities(point sources:industrial effluents and wastewater treatment plants;non-point sources:domestic sewage,livestock operations and agricultural activities) and natural processes(seasonal effect,and natural inputs).PCA/FA in the whole basin showed the best results for data reduction because it used only two parameters(about 80% reduction) as the most important parameters to explain 72% of the data variation.Thus,this work illustrated the utility of multivariate statistical techniques for analysis and interpretation of datasets and,in water quality assessment,identification of pollution sources/factors and understanding spatial variations in water quality for effective stream water quality management.展开更多
Statistical Energy Analysis(SEA)is a well-known method to analyze the flow of acoustic and vibration energy in a complex structure.This study investigates the application of the corrected SEA model in a non-reverberan...Statistical Energy Analysis(SEA)is a well-known method to analyze the flow of acoustic and vibration energy in a complex structure.This study investigates the application of the corrected SEA model in a non-reverberant acoustic space where the direct field component from the sound source dominates the total sound field rather than a diffuse field in a reverberant space which the classical SEA model assumption is based on.A corrected SEA model is proposed where the direct field component in the energy is removed and the power injected in the subsystem considers only the remaining power after the loss at first reflection.Measurement was conducted in a box divided into two rooms separated by a partition with an opening where the condition of reverberant and non-reverberant can conveniently be controlled.In the case of a non-reverberant space where acoustic material was installed inside the wall of the experimental box,the signals are corrected by eliminating the direct field component in the measured impulse response.Using the corrected SEA model,comparison of the coupling loss factor(CLF)and damping loss factor(DLF)with the theory shows good agreement.展开更多
This paper describes the experiments with Korean-to-Vietnamese statistical machine translation(SMT). The fact that Korean is a morphologically complex language that does not have clear optimal word boundaries causes a...This paper describes the experiments with Korean-to-Vietnamese statistical machine translation(SMT). The fact that Korean is a morphologically complex language that does not have clear optimal word boundaries causes a major problem of translating into or from Korean. To solve this problem, we present a method to conduct a Korean morphological analysis by using a pre-analyzed partial word-phrase dictionary(PWD).Besides, we build a Korean-Vietnamese parallel corpus for training SMT models by collecting text from multilingual magazines. Then, we apply such a morphology analysis to Korean sentences that are included in the collected parallel corpus as a preprocessing step. The experiment results demonstrate a remarkable improvement of Korean-to-Vietnamese translation quality in term of bi-lingual evaluation understudy(BLEU).展开更多
The frequent occurrence of dry and hot(DH)days in South China in summer has a negative impact on social development and human health.This study explored the variation characteristics of DH days and the possible reason...The frequent occurrence of dry and hot(DH)days in South China in summer has a negative impact on social development and human health.This study explored the variation characteristics of DH days and the possible reasons for this knotty problem.The findings revealed a notable increase in the number of DH days across most stations,indicating a significant upward trend.Additionally,DH events were observed to occur frequently.The number of DH days increased during 1970-1990,decreased from 1991 to 1997,and stayed stable after 1997.The key climate factors affecting the interannual variability of the number of DH days were the Indian Ocean Basin warming(IOBW)in spring and the East Asian Summer Monsoon(EASM).Compared with the negative phase of IOBW,in the positive phase of IOBW,500 hPa and 850 hPa geopotential height enhanced,the West Pacific subtropical high strengthened and extended abnormally to the west,more solar radiation reached the surface,surface outgoing longwave radiation increased,and there was an anomalous anticyclone in eastern South China.The atmospheric circulation characteristics of the positive and negative phases of ESAM were opposite to those of IOBW,and the abnormal circulation of the positive(negative)phases of ESAM was unfavorable(favorable)for the increase in the number of DH days.A long-term prediction model for the number of summer DH days was established using multiple linear regression,incorporating the key climate factors.The correlation coefficient between the observed and predicted number of DH days was 0.65,and the root-mean-square error was 2.8.In addition,independent forecasts for 2019 showed a deviation of just 1 day.The results of the independent recovery test confirmed the stability of the model,providing evidence that climatic factors did have an impact on DH days in South China.展开更多
In this study, a statistical model was established to estimate the groundwater table using precipitation, evaporation, the river stage of the Liangduo River, and the tide level of the Yellow Sea, as well as to predict...In this study, a statistical model was established to estimate the groundwater table using precipitation, evaporation, the river stage of the Liangduo River, and the tide level of the Yellow Sea, as well as to predict the groundwater table with easily measurable climate data in a coastal plain in eastern China. To achieve these objectives, groundwater table data from twelve wells in a farmland covering an area of 50 m ~ 150 m were measured over a 12-month period in 2013 in Dongtai City, Jiangsu Province. Trend analysis and correlation analysis were conducted to study the patterns of changes in the groundwater table. In addition, a linear regression model was established and regression analysis was conducted to understand the relationships between precipitation, evaporation, river stage, tide level, and groundwater table. The results are as follows: (1) The groundwater table was strongly affected by climate factors (e.g., precipitation and evaporation), and river stage was also a significant factor affecting the groundwater table in the study area (p 〈 0.01, where p is the probability value). (2) The groundwater table was especially sensitive to precipitation. The significance of the factors of the groundwater table were ranked in the following descending order: precipitation, evaporation, and river stage. (3) A triple linear regression model of the groundwater table, precipitation, evaporation, and river stage was established. The linear relationship between the groundwater table and the main factors was satisfied by the actual values versus the simulated values of the groundwater table (R^2 = 0.841, where R^2 is the coefficient of determination).展开更多
Mining activities interfere with the natural groundwater chemical environment,which may lead to hydrogeochemical changes of aquifers and mine water inrush disasters.This study analyzed the hydrochemical compositions o...Mining activities interfere with the natural groundwater chemical environment,which may lead to hydrogeochemical changes of aquifers and mine water inrush disasters.This study analyzed the hydrochemical compositions of 80 water samples in three aquifers and developed a water source identification model to explore the control factors and potential hydraulic connection of groundwater chemistry in a coal mine.The results showed that the hydrochemical types of the three aquifers were different.The main hydrochemical compositions of the loose-layer,coal-bearing,and limestone aquifers were HCO_(3)·Cl-Na,SO_(4)·HCO_(3)-Na,and SO_(4)-Na·Ca,respectively.The correlation,Unmix,and factor an-alyses showed that the hydrochemical composition of groundwater was controlled by the dissolution of soluble minerals(such as calcite,dolomite,gypsum,and halite)and the weathering of silicate minerals.The factor score plot combined with Q-mode cluster analysis demon-strated no remarkable hydraulic connection among the three aquifers in the study area.The water source identification model effectively identified the source of inrush water.Moreover,the mixing ratio model rationally quantified the contributions of the three aquifers to inrush water.展开更多
Based on the field survey of the foxtail millet planting,processing and sales in foxtail millet production areas,it found out basic demands of foxtail millet farmers and processing enterprises for policies. It made st...Based on the field survey of the foxtail millet planting,processing and sales in foxtail millet production areas,it found out basic demands of foxtail millet farmers and processing enterprises for policies. It made statistical analysis with the aid of SPSS statistical software. It found that current situation of China's foxtail millet industry is not optimistic. Finally,it came up with policy recommendations including enhancing actual effect of policy,establishing special fund,increasing scientific and technological support,and encouraging mechanized planting.展开更多
Understanding the controlling factor of groundwater quality can enhance promoting sustainable development of groundwater resources. To this end, multivariate statistical analysis(MA) and hydrochemical analysis were ...Understanding the controlling factor of groundwater quality can enhance promoting sustainable development of groundwater resources. To this end, multivariate statistical analysis(MA) and hydrochemical analysis were introduced in this work. The results indicate that the canonical discriminant function with 7 parameters was established using the discriminant analysis(DA) method, which can afford 100% correct assignation according to the 3 different clusters(good water(GW), poor water(PW), and very poor water(VPW)) obtained from cluster analysis(CA). According to factor analysis(FA), 8 factors were extracted from 25 hydrochemical elements and account for 80.897% of the total data variance, suggesting that groundwater with higher concentrations of sodium, calcium, magnesium, chloride, and sulfate in southeastern study area are mainly affected by the natural process; the higher level of arsenic and chromium in groundwater extracted from northwestern part of study area are derived by industrial activities; domestic and agriculture sewage have important contribution to copper, iron, iodine, and phosphate in the northern study area. Therefore, this work can help identify the main controlling factor of groundwater quality in North China plain so as to make better and more informed decisions about how to achieve groundwater resources sustainable development.展开更多
In this study, a constitutive model based on microscopic physical mechanism of silicone rubber foams was established. A theoretical statistical model of rubber elasticity considering the effect of dangling chains was ...In this study, a constitutive model based on microscopic physical mechanism of silicone rubber foams was established. A theoretical statistical model of rubber elasticity considering the effect of dangling chains was modified to build this model. When a strain amplification factor (X) was introduced, the theoretical model could fit the tensile stress-strain data of mono- and bi-modal foam matrix well (Adj. R-Square = 0.9989, 0.9983). Parameters related to the polymer network, namely, average molecular weight (Me) and volume fraction (Ф) of chain segments between adjacent cross-linking points (network strands), were calculated by probabilistic method from the number-average molecular weight (Mn), vinyl content (wvi) of the primary polysiloxanes and percent conversion (q) of vinyl groups. The primary and infinite strain amplification factors (X0, X∞) and decay exponent (z), introduced by X and related to the nanoparticles, were obtained by fitting. Inspired by the fact that the actual strain of matrix was lower than that of the foams', we introduced another item, strain hysteresis item (H, related with the foam porosity and cell structure), into the statistical model as well. With the same above values of Mc, Ф, X0 and X∞, the model could also fit the compressive stress-strain data of mono- and bi-modal foams well (Adj. R-Square = 0.9948, 0.9985). Interestingly, the strain hysteresis items of the mono- and bi-modal foams almost completely coincided under all experimental strains, which may be attributed to the almost equal porosity and similar cell structure of the two foams. This constitutive model may connect the macroscopic stress-strain behaviour to the parameters of microscopic molecular structures, promisingly providing a basis for the performance improvement and optimization of silicone rubber foams.展开更多
Objective Apatinib is a novel inhibitor of vascular endothelial growth factor receptor-2.The goal of this study was to evaluate overall survival(OS)after a combination of transarterial chemoembolization(TACE)and apati...Objective Apatinib is a novel inhibitor of vascular endothelial growth factor receptor-2.The goal of this study was to evaluate overall survival(OS)after a combination of transarterial chemoembolization(TACE)and apatinib in patients with advanced hepatocellular carcinoma(HCC)and to identify the factors affecting patient survival.Methods Fifty-one patients with advanced HCC who received TACE in combination with apatinib in our hospital from June 2015 to May 2017 were enrolled.The OS and progression-free survival(PFS)were calculated using the Kaplan-Meier method.The log-rank test and Cox regression model were used to determine the factors affecting OS.Results The median OS and PFS of the patients were 15 months and 10 months,respectively.The 1-,2-,and 3-year survival rates were 64.7%,23.5%,and 1.8%,respectively.Univariate survival analysis showed that patients with Child-Pugh A(P=0.006),reduction rate of proper hepatic artery(P=0.016),hand-foot syndrome(P=0.005),secondary hypertension(P=0.050),and without ascites(P=0.010)had a better OS.Multivariate analysis showed that hand-foot syndrome(P=0.014),secondary hypertension(P=0.017),and reduction rate of proper hepatic artery(P=0.025)were independent predictors of better OS.Conclusion TACE combined with apatinib is a promising treatment for advanced HCC.Hand-foot syndrome,secondary hypertension,and the reduction rate of proper hepatic artery were associated with a better OS.展开更多
The paper compares the correlations between individual factors of the cyclogenesis and the number of TCs formed in the western North Pacific in July to September(NTWNP). It also compares the characteristics of zonal a...The paper compares the correlations between individual factors of the cyclogenesis and the number of TCs formed in the western North Pacific in July to September(NTWNP). It also compares the characteristics of zonal anomaly distribution of the factors in the primary TC source areas of the Northern Hemisphere. Results show that the vorticity factor has the closest correlation with NTWNP. In TC genesis conditions, this feature is relatively rich but not enough, which determines that it is the sensitivity factor of NTWNP's annual variation. The paper also analyzes the source of annual variation of the vorticity factor in the key area of the western North Pacific as well as its advantage in showing NTWNP. Results show that the annual variation of the vorticity factor mentioned above is related to the annual variation of Southern Oscillation, Antarctica Oscillation and the geopotential height field of East Australia, which reflects the effect of two large-scale systems in the Southern Hemisphere and ENSO(El Ni?o–Southern Oscillation) on NTWNP. Since the area where the vorticity factor is significantly correlated with NTWNP is consistent with the area of dense TC genesis sources, the vorticity factor has an obvious advantage in showing annual variation of TCs. Those features are very significant for research on the influencing mechanism of NTWNP and simulation of climate models.展开更多
To study the water quality influenced by the anthropogenic activities and its impact on the phytoplankton diversity in the surface waters of Miaodao Archipelago, the spatiotemporal variations in phytoplankton communit...To study the water quality influenced by the anthropogenic activities and its impact on the phytoplankton diversity in the surface waters of Miaodao Archipelago, the spatiotemporal variations in phytoplankton communities and the environmental properties of the surface waters surrounding the Five Southern Islands of Miaodao Archipelago were investigated, based on seasonal field survey conducted from November 2012 to August 2013. During the survey, a total of 109 phytoplankton species from 3 groups were identified in the southern waters of Miaodao Archipelago, of which 77 were diatoms, 29 were dinoflagellates, and 3 were chrysophytes. Species number was higher in winter(73), moderate in autumn(70), but lower in summer(31) and spring(27). The species richness index in autumn(5.92) and winter(4.28) was higher than that in summer(2.83) and spring(1.41).The Shannon-Wiener diversity index was high in autumn(2.82), followed by winter(1.99) and summer(1.92), and low in spring(0.07). The species evenness index in autumn(0.46) and summer(0.39) was higher than that in winter(0.32) and spring(0.02). On the basis of principal component analysis(PCA) and redundancy analysis(RDA), we found that dissolved inorganic nitrogen(DIN) and chemical oxygen demand(COD) in spring, COD in summer, p H in autumn, and salinity and oil pollutant in winter, respectively, showed the strongest association with the distribution of phytoplankton diversity. The spatial heterogeneity of the southern waters of Miaodao Archipelago was quite obvious, and three zones, i.e., northeastern, southwestern and inter-island water area, were identified by cluster analysis(CA) based on key environmental variables.展开更多
BACKGROUND Endoscopic mucosal resection is an innovative method for treating early gastric cancer and has been widely used in clinical practice.AIM To analyze the factors associated with the development of heterochron...BACKGROUND Endoscopic mucosal resection is an innovative method for treating early gastric cancer and has been widely used in clinical practice.AIM To analyze the factors associated with the development of heterochronic gastric cancer in patients with early gastric cancer who had undergone endoscopic mucosal dissection(EMD).METHODS A cohort of patients with early gastric cancer treated using EMD was retrospectively analyzed,and patients who developed heterochronic gastric cancer after the surgery were compared with those who did not.The effects of patient age,sex,tumor size,pathological type,and surgical technique on the development of heterochronic gastric cancer were assessed using statistical analysis.RESULTS Of the 300 patients with early gastric cancer,150 patients developed heterochronic gastric cancer after EMD.Statistical analysis revealed that patient age(P value=XX),sex(P value=XX),tumor size(P value=XX),pathological type(P value=XX),and surgical technique(P value=XX)were significantly associated with the occurrence of heterochronic gastric cancer.CONCLUSION Age,sex,tumor size,pathological type,and surgical technique are key factors influencing the occurrence of heterochronic gastric cancer after EMD in patients with early gastric cancer.To address these factors,postoperative follow-up and management should be strengthened to improve the prognosis and survival rate of patients.展开更多
By using the statistical spectroscopic theory, we have discussed the form factors of some s-d shell nuclei under the mean field approximation. Without introducing any free parameters, the experimental data are well re...By using the statistical spectroscopic theory, we have discussed the form factors of some s-d shell nuclei under the mean field approximation. Without introducing any free parameters, the experimental data are well reproduced in the展开更多
BACKGROUND: Several studies have confirmed that endothelin and endorphin are involved in the occurrence of cerebral vasospasm. However, the correlation of these factors to acute cerebral infarction-related risk facto...BACKGROUND: Several studies have confirmed that endothelin and endorphin are involved in the occurrence of cerebral vasospasm. However, the correlation of these factors to acute cerebral infarction-related risk factors needs to be confirmed. OBJECTIVE: To detect endothelin-1 (ET-1) and beta-endorphin (β -EP) levels in plasma of patients with acute cerebral infarction, and to analyze the correlations of these factors to smoking, alcohol abuse, hypertension, diabetes mellitus, diseased region, diseased degree, gender, and other factors related to acute cerebral infarction. DESIGN: A case-control observation. SETTING: First Department of Neurology, Guangdong Hospital of Traditional Chinese Medicine; Department of Neurology, Second Affiliated Hospital of Sun Yat-sen University. PARTICIPANTS: Sixty-nine inpatients with acute cerebral infarction were admitted to the Department of Neurology, Second Affiliated Hospital of Sun Yat-sen University (March 2003-January 2004) and First Department of Neurology, Guangdong Hospital of Traditional Chinese Medicine (March July 2004) and recruited for this study. All 69 inpatients corresponded to the diagnosis criteria of acute cerebral infarction, formulated in the National Working Conference of Cerebrovascular Disease in 1998, and were confirmed as acute cerebral infarction by CT/MRI. The patient group consisted of 35 males [(644- 12) years old] and 34 females[ (674- 13 ) years old]. Among them, 9 patients were smokers, 7 were alcohol users, 48 had a history of hypertension, and 16 had a history of diabetes mellitus. CT/MRI examinations revealed that 35 patients presented with left focus sites, 11 with right ones and 23 with bilateral ones. Following attack, 24 patients had Barthel Index Scale grading 〈 40 points, 21 patients 40-50 points, and 24 patients 〉 60 points. An additional 59 healthy individuals, who received health examinations simultaneously, were included as controls. Among the control subjects, there were 37 males [(62±10) years old] and 22 females [(65±11) years old]. Among them, 7 patients were smokers, and 6 were alcohol users. All controls had no history of stroke, hypertension, or diabetes mellitus. Informed consents of laboratory measurements were obtained from all subjects, and this study was approved by the Hospital Ethics Committee. METHODS: ① Following admission, all subjects were scored by Barthel Index Scale (BIS) and Hamilton Depression Scale. Meanwhile, hypertension, diabetes mellitus, gender, smoking, drinking, and other conditions were recorded. CT/MRI examination was conducted to identify the focus site.②On the 2^nd day after admission, ET-1 and β -EP plasma levels were measured with an automatic ET-1 and β -EP analysis kit. MAIN OUTCOME MEASURES: ET-1 and β -EP plasma levels and their correlation to acute cerebral infarction-related factors. RESULTS: Sixty-nine patients with acute cerebral infarction, and an additional 59 healthy individuals participated in the final analysis. β ET-1 [(63.80±27.65) ng/L vs. (46.50±9.36) ng/L, P 〈 0.05] and β - EP [(94.18±33.94) mg/L vs. (51.87±23.43) mg/L, P 〈 0.05] levels of the patient group were obviously higher than respective values of the control group. ② The ET-1 and β -EP levels of patients with cerebral infarction did not correlate to hypertension, diabetes mellitus, BIS, depression, cerebral infarct focus, disease course, gender, smoking or drinking (P 〉 0.05). CONCLUSION: The ET-I and β-EP levels of patients with acute cerebral infarction increased, but they were not obviously associated with disease course, blood pressure, blood glucose, BIS, or other common cerebral infarction-related factors.展开更多
Earthquake-induced landslides are difficult to assess and predict owing to the inherent unpredictability of earthquakes.In most existing studies,the landslide potential is statistically assessed by collecting and anal...Earthquake-induced landslides are difficult to assess and predict owing to the inherent unpredictability of earthquakes.In most existing studies,the landslide potential is statistically assessed by collecting and analyzing the data of historical landslide events and earthquake observation records.Unlike rainfall-induced landslides,earthquake-induced landslides cannot be predicted in advance using real-time monitoring systems,and the development of the models for these landslides should instead depend on early earthquake warnings and estimations.Hence,in this study,factor analysis was performed and the frequency distribution method was employed to investigate the potential risk of the landslides caused by earthquakes.Factors such as the slope gradient,lithology(geology),aspect,and elevation were selected and classified as influential factors to facilitate the construction of a landslide database for the area of study.展开更多
In complex terrain regions, it is very challenging to obtain high accuracy and resolution precipitation data that are required in land hydrological studies. In this study, an adaptive precipitation downscaling method ...In complex terrain regions, it is very challenging to obtain high accuracy and resolution precipitation data that are required in land hydrological studies. In this study, an adaptive precipitation downscaling method is proposed based on the statistical downscaling model MicroMet. A key input parameter in the MicroMet is the precipitation adjustment factor(PAF) that shows the elevation dependence of precipitation. Its value is estimated conventionally based on station observations and suffers sparse stations in high altitudes. This study proposes to estimate the PAF value and its spatial variability with precipitation data from high-resolution atmospheric simulations and tests the idea in Nepal of South Himalayas, where rainfall stations are relatively dense. The result shows that MicroMet performs the best with the PAF value estimated from the simulation data at the scale of approximately 1.5 degrees. Not only the value at this scale is qualitatively consistent with early knowledge obtained from intensive observations, but also the downscaling performance with this value is better than or comparable to that with the PAF estimated from dense station data. Finally, it is shown that the PAF estimation, although critical, cannot replace the importance of increasing input station density for downscaling.展开更多
Hospital is an important factor of people’s livelihood security,and the spatial layout of hospitals effectively ensures the medical convenience for residents.Location entropy and mathematical statistical analysis are...Hospital is an important factor of people’s livelihood security,and the spatial layout of hospitals effectively ensures the medical convenience for residents.Location entropy and mathematical statistical analysis are used to study spatial distribution of hospitals.The results display that the distribution of medical facilities in Handan City is at a disadvantage level in Hebei Province,and medical facilities arr concentrated in the plain area.The layout of grade 3A hospitals in Hebei Province is characterized by urban centralization,and it is stronger in the east and weaker in the west.There is no medical facilities in Feixiang District of Handan City,and layout of medical facilities in Hanshan District and Congtai District is at advantage level of Handan City.The built-up area is the influencing factor for the distribution of medical resources.展开更多
基金Supported by National Natural Science Foundation of China(No.10472077).
文摘Based on the data of phytoplankton concentration and environmental factors in Bohai Bay from May to September in 2003. the relationship between environmental factors and phytoplankton biomass was analyzed. By analysis of variance, the weather condition was found to have no direct relation with phytoplankton biomass. Correlation coefficients showed that temperature, pH value,the concentrations of silicate and nitrate exhibited linear relationship with phytoplankton biomass.With principal component analysis, pollution types which affected the abundance of phytoplankton included point sources such as municipal and industrial effluents, agricultural runoff and earth's surface water. Using multivariate stepwise regression method and taking the correlation analysis results into consideration, a multi-step regression equation was developed to predict the concentration of phytoplankton in September 2003. Combined results show that temperature, pH value, the concentrations of silicate and nitrate are the critical ecological factors affecting the phytoplankton biomass in Bohai Bay.
基金Project (2012ZX07501002-001) supported by the Ministry of Science and Technology of China
文摘Multivariate statistical techniques,such as cluster analysis(CA),discriminant analysis(DA),principal component analysis(PCA) and factor analysis(FA),were applied to evaluate and interpret the surface water quality data sets of the Second Songhua River(SSHR) basin in China,obtained during two years(2012-2013) of monitoring of 10 physicochemical parameters at 15 different sites.The results showed that most of physicochemical parameters varied significantly among the sampling sites.Three significant groups,highly polluted(HP),moderately polluted(MP) and less polluted(LP),of sampling sites were obtained through Hierarchical agglomerative CA on the basis of similarity of water quality characteristics.DA identified p H,F,DO,NH3-N,COD and VPhs were the most important parameters contributing to spatial variations of surface water quality.However,DA did not give a considerable data reduction(40% reduction).PCA/FA resulted in three,three and four latent factors explaining 70%,62% and 71% of the total variance in water quality data sets of HP,MP and LP regions,respectively.FA revealed that the SSHR water chemistry was strongly affected by anthropogenic activities(point sources:industrial effluents and wastewater treatment plants;non-point sources:domestic sewage,livestock operations and agricultural activities) and natural processes(seasonal effect,and natural inputs).PCA/FA in the whole basin showed the best results for data reduction because it used only two parameters(about 80% reduction) as the most important parameters to explain 72% of the data variation.Thus,this work illustrated the utility of multivariate statistical techniques for analysis and interpretation of datasets and,in water quality assessment,identification of pollution sources/factors and understanding spatial variations in water quality for effective stream water quality management.
基金the financial support provided for this project by the Ministry of Higher Education Malaysia(MoHE)under Fundamental Research Grant Scheme No.FRGS/1/2016/FTK-CARE/F00323.
文摘Statistical Energy Analysis(SEA)is a well-known method to analyze the flow of acoustic and vibration energy in a complex structure.This study investigates the application of the corrected SEA model in a non-reverberant acoustic space where the direct field component from the sound source dominates the total sound field rather than a diffuse field in a reverberant space which the classical SEA model assumption is based on.A corrected SEA model is proposed where the direct field component in the energy is removed and the power injected in the subsystem considers only the remaining power after the loss at first reflection.Measurement was conducted in a box divided into two rooms separated by a partition with an opening where the condition of reverberant and non-reverberant can conveniently be controlled.In the case of a non-reverberant space where acoustic material was installed inside the wall of the experimental box,the signals are corrected by eliminating the direct field component in the measured impulse response.Using the corrected SEA model,comparison of the coupling loss factor(CLF)and damping loss factor(DLF)with the theory shows good agreement.
基金supported by the Institute for Information&communications Technology Promotion under Grant No.R0101-16-0176the Project of Core Technology Development for Human-Like Self-Taught Learning Based on Symbolic Approach
文摘This paper describes the experiments with Korean-to-Vietnamese statistical machine translation(SMT). The fact that Korean is a morphologically complex language that does not have clear optimal word boundaries causes a major problem of translating into or from Korean. To solve this problem, we present a method to conduct a Korean morphological analysis by using a pre-analyzed partial word-phrase dictionary(PWD).Besides, we build a Korean-Vietnamese parallel corpus for training SMT models by collecting text from multilingual magazines. Then, we apply such a morphology analysis to Korean sentences that are included in the collected parallel corpus as a preprocessing step. The experiment results demonstrate a remarkable improvement of Korean-to-Vietnamese translation quality in term of bi-lingual evaluation understudy(BLEU).
基金National Natural Science Foundation of China(92044302,41805115)Guangzhou Municipal Science and Technology Project(202002020065)。
文摘The frequent occurrence of dry and hot(DH)days in South China in summer has a negative impact on social development and human health.This study explored the variation characteristics of DH days and the possible reasons for this knotty problem.The findings revealed a notable increase in the number of DH days across most stations,indicating a significant upward trend.Additionally,DH events were observed to occur frequently.The number of DH days increased during 1970-1990,decreased from 1991 to 1997,and stayed stable after 1997.The key climate factors affecting the interannual variability of the number of DH days were the Indian Ocean Basin warming(IOBW)in spring and the East Asian Summer Monsoon(EASM).Compared with the negative phase of IOBW,in the positive phase of IOBW,500 hPa and 850 hPa geopotential height enhanced,the West Pacific subtropical high strengthened and extended abnormally to the west,more solar radiation reached the surface,surface outgoing longwave radiation increased,and there was an anomalous anticyclone in eastern South China.The atmospheric circulation characteristics of the positive and negative phases of ESAM were opposite to those of IOBW,and the abnormal circulation of the positive(negative)phases of ESAM was unfavorable(favorable)for the increase in the number of DH days.A long-term prediction model for the number of summer DH days was established using multiple linear regression,incorporating the key climate factors.The correlation coefficient between the observed and predicted number of DH days was 0.65,and the root-mean-square error was 2.8.In addition,independent forecasts for 2019 showed a deviation of just 1 day.The results of the independent recovery test confirmed the stability of the model,providing evidence that climatic factors did have an impact on DH days in South China.
基金supported by the Sate Key Program of the National Natural Science Foundation of China(Grant No.51479063)the Public Welfare Industry Special Funds for Scientific Research Projects of the Ministry of Water Resources(Grant No.200801025)the Innovative Projects of Scientific Research for Postgraduates in Ordinary Universities in Jiangsu Province(Grant No.CXZZ13_0267)
文摘In this study, a statistical model was established to estimate the groundwater table using precipitation, evaporation, the river stage of the Liangduo River, and the tide level of the Yellow Sea, as well as to predict the groundwater table with easily measurable climate data in a coastal plain in eastern China. To achieve these objectives, groundwater table data from twelve wells in a farmland covering an area of 50 m ~ 150 m were measured over a 12-month period in 2013 in Dongtai City, Jiangsu Province. Trend analysis and correlation analysis were conducted to study the patterns of changes in the groundwater table. In addition, a linear regression model was established and regression analysis was conducted to understand the relationships between precipitation, evaporation, river stage, tide level, and groundwater table. The results are as follows: (1) The groundwater table was strongly affected by climate factors (e.g., precipitation and evaporation), and river stage was also a significant factor affecting the groundwater table in the study area (p 〈 0.01, where p is the probability value). (2) The groundwater table was especially sensitive to precipitation. The significance of the factors of the groundwater table were ranked in the following descending order: precipitation, evaporation, and river stage. (3) A triple linear regression model of the groundwater table, precipitation, evaporation, and river stage was established. The linear relationship between the groundwater table and the main factors was satisfied by the actual values versus the simulated values of the groundwater table (R^2 = 0.841, where R^2 is the coefficient of determination).
基金supported by the Natural Science Research Project of Universities in Anhui Province(Grants No.KJ2020ZD64 and KJ2020A0740)the Anhui Provincial Natural Science Foundation(Grant No.2008085MD122)+3 种基金the Zhejiang Provincial Natural Science Foundation(Grant No.LQ20D010009)the Key Program for Outstanding Young Talents in Higher Education Institutions of Anhui Province(Grant No.gxyqZD2021134)the Research Development Foundation of Suzhou University(Grant No.2021fzjj28)the Doctoral Scientific Reuter Foundation of Suzhou University(Grant No.2019jb15).
文摘Mining activities interfere with the natural groundwater chemical environment,which may lead to hydrogeochemical changes of aquifers and mine water inrush disasters.This study analyzed the hydrochemical compositions of 80 water samples in three aquifers and developed a water source identification model to explore the control factors and potential hydraulic connection of groundwater chemistry in a coal mine.The results showed that the hydrochemical types of the three aquifers were different.The main hydrochemical compositions of the loose-layer,coal-bearing,and limestone aquifers were HCO_(3)·Cl-Na,SO_(4)·HCO_(3)-Na,and SO_(4)-Na·Ca,respectively.The correlation,Unmix,and factor an-alyses showed that the hydrochemical composition of groundwater was controlled by the dissolution of soluble minerals(such as calcite,dolomite,gypsum,and halite)and the weathering of silicate minerals.The factor score plot combined with Q-mode cluster analysis demon-strated no remarkable hydraulic connection among the three aquifers in the study area.The water source identification model effectively identified the source of inrush water.Moreover,the mixing ratio model rationally quantified the contributions of the three aquifers to inrush water.
基金Supported by Special Project for Construction of Modern Agricultural Industrial Technology System of the Ministry of Agriculture and Ministry of Finance(CARS-07-12.5-A18)
文摘Based on the field survey of the foxtail millet planting,processing and sales in foxtail millet production areas,it found out basic demands of foxtail millet farmers and processing enterprises for policies. It made statistical analysis with the aid of SPSS statistical software. It found that current situation of China's foxtail millet industry is not optimistic. Finally,it came up with policy recommendations including enhancing actual effect of policy,establishing special fund,increasing scientific and technological support,and encouraging mechanized planting.
基金supported by the Major State Basic Research Development Program (No. 2010CB428800)the Geological Survey Projects Foundation of Institute of Hydrogeology and Environmental Geology (No. SK201308)
文摘Understanding the controlling factor of groundwater quality can enhance promoting sustainable development of groundwater resources. To this end, multivariate statistical analysis(MA) and hydrochemical analysis were introduced in this work. The results indicate that the canonical discriminant function with 7 parameters was established using the discriminant analysis(DA) method, which can afford 100% correct assignation according to the 3 different clusters(good water(GW), poor water(PW), and very poor water(VPW)) obtained from cluster analysis(CA). According to factor analysis(FA), 8 factors were extracted from 25 hydrochemical elements and account for 80.897% of the total data variance, suggesting that groundwater with higher concentrations of sodium, calcium, magnesium, chloride, and sulfate in southeastern study area are mainly affected by the natural process; the higher level of arsenic and chromium in groundwater extracted from northwestern part of study area are derived by industrial activities; domestic and agriculture sewage have important contribution to copper, iron, iodine, and phosphate in the northern study area. Therefore, this work can help identify the main controlling factor of groundwater quality in North China plain so as to make better and more informed decisions about how to achieve groundwater resources sustainable development.
基金financially supported by the National Natural Science Foundation of China(Nos.51473151 and 51703210)
文摘In this study, a constitutive model based on microscopic physical mechanism of silicone rubber foams was established. A theoretical statistical model of rubber elasticity considering the effect of dangling chains was modified to build this model. When a strain amplification factor (X) was introduced, the theoretical model could fit the tensile stress-strain data of mono- and bi-modal foam matrix well (Adj. R-Square = 0.9989, 0.9983). Parameters related to the polymer network, namely, average molecular weight (Me) and volume fraction (Ф) of chain segments between adjacent cross-linking points (network strands), were calculated by probabilistic method from the number-average molecular weight (Mn), vinyl content (wvi) of the primary polysiloxanes and percent conversion (q) of vinyl groups. The primary and infinite strain amplification factors (X0, X∞) and decay exponent (z), introduced by X and related to the nanoparticles, were obtained by fitting. Inspired by the fact that the actual strain of matrix was lower than that of the foams', we introduced another item, strain hysteresis item (H, related with the foam porosity and cell structure), into the statistical model as well. With the same above values of Mc, Ф, X0 and X∞, the model could also fit the compressive stress-strain data of mono- and bi-modal foams well (Adj. R-Square = 0.9948, 0.9985). Interestingly, the strain hysteresis items of the mono- and bi-modal foams almost completely coincided under all experimental strains, which may be attributed to the almost equal porosity and similar cell structure of the two foams. This constitutive model may connect the macroscopic stress-strain behaviour to the parameters of microscopic molecular structures, promisingly providing a basis for the performance improvement and optimization of silicone rubber foams.
基金supported by the National Natural Science Foundation of China(No.81771950,No.81471765 and No.81601578).
文摘Objective Apatinib is a novel inhibitor of vascular endothelial growth factor receptor-2.The goal of this study was to evaluate overall survival(OS)after a combination of transarterial chemoembolization(TACE)and apatinib in patients with advanced hepatocellular carcinoma(HCC)and to identify the factors affecting patient survival.Methods Fifty-one patients with advanced HCC who received TACE in combination with apatinib in our hospital from June 2015 to May 2017 were enrolled.The OS and progression-free survival(PFS)were calculated using the Kaplan-Meier method.The log-rank test and Cox regression model were used to determine the factors affecting OS.Results The median OS and PFS of the patients were 15 months and 10 months,respectively.The 1-,2-,and 3-year survival rates were 64.7%,23.5%,and 1.8%,respectively.Univariate survival analysis showed that patients with Child-Pugh A(P=0.006),reduction rate of proper hepatic artery(P=0.016),hand-foot syndrome(P=0.005),secondary hypertension(P=0.050),and without ascites(P=0.010)had a better OS.Multivariate analysis showed that hand-foot syndrome(P=0.014),secondary hypertension(P=0.017),and reduction rate of proper hepatic artery(P=0.025)were independent predictors of better OS.Conclusion TACE combined with apatinib is a promising treatment for advanced HCC.Hand-foot syndrome,secondary hypertension,and the reduction rate of proper hepatic artery were associated with a better OS.
基金Program for Key Science and Technology Planning on Applied Research and Industrialization of Hainan Province,China(ZDXM20130081)
文摘The paper compares the correlations between individual factors of the cyclogenesis and the number of TCs formed in the western North Pacific in July to September(NTWNP). It also compares the characteristics of zonal anomaly distribution of the factors in the primary TC source areas of the Northern Hemisphere. Results show that the vorticity factor has the closest correlation with NTWNP. In TC genesis conditions, this feature is relatively rich but not enough, which determines that it is the sensitivity factor of NTWNP's annual variation. The paper also analyzes the source of annual variation of the vorticity factor in the key area of the western North Pacific as well as its advantage in showing NTWNP. Results show that the annual variation of the vorticity factor mentioned above is related to the annual variation of Southern Oscillation, Antarctica Oscillation and the geopotential height field of East Australia, which reflects the effect of two large-scale systems in the Southern Hemisphere and ENSO(El Ni?o–Southern Oscillation) on NTWNP. Since the area where the vorticity factor is significantly correlated with NTWNP is consistent with the area of dense TC genesis sources, the vorticity factor has an obvious advantage in showing annual variation of TCs. Those features are very significant for research on the influencing mechanism of NTWNP and simulation of climate models.
基金The Special Project of Science and Technology Fundamental Work from the Ministry of Science and Technology of China under contract No.2012FY112500the National Natural Science Foundation of China under contract Nos 41206111 and 41206112
文摘To study the water quality influenced by the anthropogenic activities and its impact on the phytoplankton diversity in the surface waters of Miaodao Archipelago, the spatiotemporal variations in phytoplankton communities and the environmental properties of the surface waters surrounding the Five Southern Islands of Miaodao Archipelago were investigated, based on seasonal field survey conducted from November 2012 to August 2013. During the survey, a total of 109 phytoplankton species from 3 groups were identified in the southern waters of Miaodao Archipelago, of which 77 were diatoms, 29 were dinoflagellates, and 3 were chrysophytes. Species number was higher in winter(73), moderate in autumn(70), but lower in summer(31) and spring(27). The species richness index in autumn(5.92) and winter(4.28) was higher than that in summer(2.83) and spring(1.41).The Shannon-Wiener diversity index was high in autumn(2.82), followed by winter(1.99) and summer(1.92), and low in spring(0.07). The species evenness index in autumn(0.46) and summer(0.39) was higher than that in winter(0.32) and spring(0.02). On the basis of principal component analysis(PCA) and redundancy analysis(RDA), we found that dissolved inorganic nitrogen(DIN) and chemical oxygen demand(COD) in spring, COD in summer, p H in autumn, and salinity and oil pollutant in winter, respectively, showed the strongest association with the distribution of phytoplankton diversity. The spatial heterogeneity of the southern waters of Miaodao Archipelago was quite obvious, and three zones, i.e., northeastern, southwestern and inter-island water area, were identified by cluster analysis(CA) based on key environmental variables.
文摘BACKGROUND Endoscopic mucosal resection is an innovative method for treating early gastric cancer and has been widely used in clinical practice.AIM To analyze the factors associated with the development of heterochronic gastric cancer in patients with early gastric cancer who had undergone endoscopic mucosal dissection(EMD).METHODS A cohort of patients with early gastric cancer treated using EMD was retrospectively analyzed,and patients who developed heterochronic gastric cancer after the surgery were compared with those who did not.The effects of patient age,sex,tumor size,pathological type,and surgical technique on the development of heterochronic gastric cancer were assessed using statistical analysis.RESULTS Of the 300 patients with early gastric cancer,150 patients developed heterochronic gastric cancer after EMD.Statistical analysis revealed that patient age(P value=XX),sex(P value=XX),tumor size(P value=XX),pathological type(P value=XX),and surgical technique(P value=XX)were significantly associated with the occurrence of heterochronic gastric cancer.CONCLUSION Age,sex,tumor size,pathological type,and surgical technique are key factors influencing the occurrence of heterochronic gastric cancer after EMD in patients with early gastric cancer.To address these factors,postoperative follow-up and management should be strengthened to improve the prognosis and survival rate of patients.
文摘By using the statistical spectroscopic theory, we have discussed the form factors of some s-d shell nuclei under the mean field approximation. Without introducing any free parameters, the experimental data are well reproduced in the
文摘BACKGROUND: Several studies have confirmed that endothelin and endorphin are involved in the occurrence of cerebral vasospasm. However, the correlation of these factors to acute cerebral infarction-related risk factors needs to be confirmed. OBJECTIVE: To detect endothelin-1 (ET-1) and beta-endorphin (β -EP) levels in plasma of patients with acute cerebral infarction, and to analyze the correlations of these factors to smoking, alcohol abuse, hypertension, diabetes mellitus, diseased region, diseased degree, gender, and other factors related to acute cerebral infarction. DESIGN: A case-control observation. SETTING: First Department of Neurology, Guangdong Hospital of Traditional Chinese Medicine; Department of Neurology, Second Affiliated Hospital of Sun Yat-sen University. PARTICIPANTS: Sixty-nine inpatients with acute cerebral infarction were admitted to the Department of Neurology, Second Affiliated Hospital of Sun Yat-sen University (March 2003-January 2004) and First Department of Neurology, Guangdong Hospital of Traditional Chinese Medicine (March July 2004) and recruited for this study. All 69 inpatients corresponded to the diagnosis criteria of acute cerebral infarction, formulated in the National Working Conference of Cerebrovascular Disease in 1998, and were confirmed as acute cerebral infarction by CT/MRI. The patient group consisted of 35 males [(644- 12) years old] and 34 females[ (674- 13 ) years old]. Among them, 9 patients were smokers, 7 were alcohol users, 48 had a history of hypertension, and 16 had a history of diabetes mellitus. CT/MRI examinations revealed that 35 patients presented with left focus sites, 11 with right ones and 23 with bilateral ones. Following attack, 24 patients had Barthel Index Scale grading 〈 40 points, 21 patients 40-50 points, and 24 patients 〉 60 points. An additional 59 healthy individuals, who received health examinations simultaneously, were included as controls. Among the control subjects, there were 37 males [(62±10) years old] and 22 females [(65±11) years old]. Among them, 7 patients were smokers, and 6 were alcohol users. All controls had no history of stroke, hypertension, or diabetes mellitus. Informed consents of laboratory measurements were obtained from all subjects, and this study was approved by the Hospital Ethics Committee. METHODS: ① Following admission, all subjects were scored by Barthel Index Scale (BIS) and Hamilton Depression Scale. Meanwhile, hypertension, diabetes mellitus, gender, smoking, drinking, and other conditions were recorded. CT/MRI examination was conducted to identify the focus site.②On the 2^nd day after admission, ET-1 and β -EP plasma levels were measured with an automatic ET-1 and β -EP analysis kit. MAIN OUTCOME MEASURES: ET-1 and β -EP plasma levels and their correlation to acute cerebral infarction-related factors. RESULTS: Sixty-nine patients with acute cerebral infarction, and an additional 59 healthy individuals participated in the final analysis. β ET-1 [(63.80±27.65) ng/L vs. (46.50±9.36) ng/L, P 〈 0.05] and β - EP [(94.18±33.94) mg/L vs. (51.87±23.43) mg/L, P 〈 0.05] levels of the patient group were obviously higher than respective values of the control group. ② The ET-1 and β -EP levels of patients with cerebral infarction did not correlate to hypertension, diabetes mellitus, BIS, depression, cerebral infarct focus, disease course, gender, smoking or drinking (P 〉 0.05). CONCLUSION: The ET-I and β-EP levels of patients with acute cerebral infarction increased, but they were not obviously associated with disease course, blood pressure, blood glucose, BIS, or other common cerebral infarction-related factors.
基金a part of the research sponsored by the Ministry of Science and Technology,Taiwan,China(Contract No.MOST 105-2221-E-035-074)Soil and Water Conservation Bureau,Taiwan,China(Contract No.SWCB-106-055).
文摘Earthquake-induced landslides are difficult to assess and predict owing to the inherent unpredictability of earthquakes.In most existing studies,the landslide potential is statistically assessed by collecting and analyzing the data of historical landslide events and earthquake observation records.Unlike rainfall-induced landslides,earthquake-induced landslides cannot be predicted in advance using real-time monitoring systems,and the development of the models for these landslides should instead depend on early earthquake warnings and estimations.Hence,in this study,factor analysis was performed and the frequency distribution method was employed to investigate the potential risk of the landslides caused by earthquakes.Factors such as the slope gradient,lithology(geology),aspect,and elevation were selected and classified as influential factors to facilitate the construction of a landslide database for the area of study.
基金Supported by the Second Tibetan Plateau Scientific Expedition and Research Program (STEP)(2019QZKK0206)National Natural Science Foundation of China (41501078, 41871071, and 41905087)。
文摘In complex terrain regions, it is very challenging to obtain high accuracy and resolution precipitation data that are required in land hydrological studies. In this study, an adaptive precipitation downscaling method is proposed based on the statistical downscaling model MicroMet. A key input parameter in the MicroMet is the precipitation adjustment factor(PAF) that shows the elevation dependence of precipitation. Its value is estimated conventionally based on station observations and suffers sparse stations in high altitudes. This study proposes to estimate the PAF value and its spatial variability with precipitation data from high-resolution atmospheric simulations and tests the idea in Nepal of South Himalayas, where rainfall stations are relatively dense. The result shows that MicroMet performs the best with the PAF value estimated from the simulation data at the scale of approximately 1.5 degrees. Not only the value at this scale is qualitatively consistent with early knowledge obtained from intensive observations, but also the downscaling performance with this value is better than or comparable to that with the PAF estimated from dense station data. Finally, it is shown that the PAF estimation, although critical, cannot replace the importance of increasing input station density for downscaling.
基金Sponsored by the Construction Project of Postgraduate Demonstration Course in Hebei Province (KCJSX2020081)。
文摘Hospital is an important factor of people’s livelihood security,and the spatial layout of hospitals effectively ensures the medical convenience for residents.Location entropy and mathematical statistical analysis are used to study spatial distribution of hospitals.The results display that the distribution of medical facilities in Handan City is at a disadvantage level in Hebei Province,and medical facilities arr concentrated in the plain area.The layout of grade 3A hospitals in Hebei Province is characterized by urban centralization,and it is stronger in the east and weaker in the west.There is no medical facilities in Feixiang District of Handan City,and layout of medical facilities in Hanshan District and Congtai District is at advantage level of Handan City.The built-up area is the influencing factor for the distribution of medical resources.