A combination of the optimal subset regression (OSR) approach,the coupled general circulation model of the National Climate Center (NCC-CGCM) and precipitation observations from 160 stations over China is used to cons...A combination of the optimal subset regression (OSR) approach,the coupled general circulation model of the National Climate Center (NCC-CGCM) and precipitation observations from 160 stations over China is used to construct a statistical downscaling forecast model for precipitation in summer.Retroactive forecasts are performed to assess the skill of statistical downscaling during the period from 2003 to 2009.The results show a poor simulation for summer precipitation by the NCCCGCM for China,and the average spatial anomaly correlation coefficient (ACC) is 0.01 in the forecast period.The forecast skill can be improved by OSR statistical downscaling,and the OSR forecast performs better than the NCC-CGCM in most years except 2003.The spatial ACC is more than 0.2 in the years 2008 and 2009,which proves to be relatively skillful.Moreover,the statistical downscaling forecast performs relatively well for the main rain belt of the summer precipitation in some years,including 2005,2006,2008,and 2009.However,the forecast skill of statistical downscaling is restricted to some extent by the relatively low skill of the NCCCGCM.展开更多
Background Atrial fibrillation (AF) catheter ablation has emerged as a promising treatment strategy for AF, but has not been widely adopted in the elderly population. The present study aimed to determine the safety ...Background Atrial fibrillation (AF) catheter ablation has emerged as a promising treatment strategy for AF, but has not been widely adopted in the elderly population. The present study aimed to determine the safety and efficacy of AF catheter ablation in the elderly popula-tion. Methods and Results The study population consisted of 316 patients with paroxysmal AF who underwent left atrial ablation. Ninety-five patients were≥65 years (48 males, mean age 68.9 ± 3.0 years old) and 221 patients were〈65 years old (130 males, mean age 52.5 ± 10.4 years old). After a mean follow-up period of 34.0 ± 15.1 months, 55 (57.9%) patients in the elderly group were free from ar-rhythmia recurrence compared with 149 (67.4%) patients in the younger group (P=0.169). Procedural complications were uncommon in both study groups. In logistic regression analysis, left atrial diameter (P=0.003), hypertension (P=0.001), dyslipidemia (P=0.039), and coronary artery disease (P=0.018) were independent predictors of AF recurrence in the elderly population. Conclusions Catheter ablation of AF is safe and effective in older patients. Invasive strategies should be considered as an alternative choice in symptomatic elderly patients with AF.展开更多
The occurrence and the detection system of mesophilic and psychrotrophic aerobic sporulating microorganisms (MPAS) in raw cow's milk were studied. Samples of raw cow's bulk tank milk were taken 21 times in 14 farm...The occurrence and the detection system of mesophilic and psychrotrophic aerobic sporulating microorganisms (MPAS) in raw cow's milk were studied. Samples of raw cow's bulk tank milk were taken 21 times in 14 farms during one year. Basis of the method for MPAS assessment is the milk sample inactivation at the temperature 80-82 ℃ for 30 minutes followed by incubation in cultivation dishes at 30 -4- 1 ℃ for 3 days-mesophilic aerobic sporulates (MAS), and at 6.5 .4- 1 ℃ for 10 days-psychrotrophic aerobic sporulates (PAS). The total count of MPAS was within the span 2.5-340 CFU/mL (colony forming units). Average plate count of MPAS was 59.4 CFU/mL with variation coefficient 93.1%. MPAS count found in the same dishes at incubation for mesophilic and subsequently strictly psychrophilic microorganisms (MAS + SPAS) which enables to exclude overestimation of results by sporulates able to grow at both incubation temperatures was on average 56.9 CFU/mL what represents 95.8% out of the number of sums of individual dishes at two temperatures (MAS + PAS). Correlation coefficient of these two types of results r = 0.99 gives evidence of close dependence that is expressed by linear regression equation y = 0.9773x. We can consider the method using at first 30 .4- 1 ℃ and subsequently 6.5 -4-1℃ (MAS + SPAS) as more correct than the method with the opposite order of cultivation temperatures because of better regression coefficient of linear dependence and higher correlation coefficient in relation to the sum of independent incubations (MAS + PAS).展开更多
In this paper, the authors explore the potential of several popular equalization techniques while overcoming their disadvantages. First, extensive literature survey on equalization is conducted. The focus is on popula...In this paper, the authors explore the potential of several popular equalization techniques while overcoming their disadvantages. First, extensive literature survey on equalization is conducted. The focus is on popular linear equalization algorithms such as the conventional least mean square (LMS ) algorithm, the recursive least squares ( RLS ) algorithm, the filtered X LMS algorithm and their development. To overcome the slow convergence problem while keeping the simplicity of the LMS based algorithms, an H 2 optimal initialization is proposed.展开更多
Air temperature and relative humidity have been the main parameters of meteorology study. In the past data could be obtained from in-situ observations, but the observations are local and sparse, especially over ocean....Air temperature and relative humidity have been the main parameters of meteorology study. In the past data could be obtained from in-situ observations, but the observations are local and sparse, especially over ocean. Now we can get them from satellites, yet it is hard to estimate them from sat- ellites directly so far. This paper presents a new method to retrieve monthly averaged sea air temper- ature (SAT) and relative humidity (RH) near sea surface from satellite data with artificial neural networks (ANN). Compared with the observations in Pacific and Atlantic, the root mean square (RMS) and the correlation between the estimated SAT and the observations are about 0.91 ~C and 0.99, respectively. The RMS and the correlation of RH are about 3.73% and 0.65, respectively. Compared with the multiple regression method, the ANN methodology is more powerful in building nonlinear relations in this research. Thus the global monthly average SAT and RH are retrieved from the fixed ANN network from July 1987 to May 2004. In general the annual average SAT shows the increasing trend in recent 18 years. The abnormality of SAT is decomposed with the empirical or- thogonal function (EOF). The leading three EOFs could explain 84% of the total variation. EOF1 (76.1%) presents the seasonal change of the SAT abnormality. EOF2 (4.6%) is mainly related with ENSO. EOF3 (3.3%) shows some new interesting phenomena appearing in the three main currents in Pacific, Atlantic and Indian Ocean.展开更多
Changes in barometric pressure can affect the micro-dynamic state of groundwater level.The groundwater level data carry a lot of important information of tectonic activity and earthquakes.It is very significant to eli...Changes in barometric pressure can affect the micro-dynamic state of groundwater level.The groundwater level data carry a lot of important information of tectonic activity and earthquakes.It is very significant to eliminate the barometric pressure effects from the groundwater level data in order to recognize seismic anomalies effectively.With the analysis of the main influential constituents of barometric pressure and their changes,we can have a better understanding of the changes of the aquifer medium,which can provide useful information for earthquake prediction.Taking the May 12,2008 Wenchuan earthquake as an example,this paper deals with the influence of barometric pressure on groundwater level based on observational data from Nanxi,Qionglai and Chaohu wells.The methods of the linear regression and the deconvolution regression were employed to remove the barometric pressure from the groundwater level data.The harmonic analysis and the spectral analysis were used to recognize the main influential waves of barometric pressure effect.A comparison was conducted on the main influential waves before and after the earthquake.The results showed that the main influential waves of barometric pressure effect changed and the amplitudes of all constituents also changed.This phenomenon may result from the characteristics of the influential constituents of pressure,or from the changes of the aquifer medium,which were caused by the earthquake.展开更多
This paper proposes a hybrid forecasting method to forecast container throughput of Qingdao Port.To eliminate the influence of outliers,local outlier factor(lof) is extended to detect outliers in time series,and then ...This paper proposes a hybrid forecasting method to forecast container throughput of Qingdao Port.To eliminate the influence of outliers,local outlier factor(lof) is extended to detect outliers in time series,and then different dummy variables are constructed to capture the effect of outliers based on domain knowledge.Next,a hybrid forecasting model combining projection pursuit regression(PPR) and genetic programming(GP) algorithm is proposed.Finally,the hybrid model is applied to forecasting container throughput of Qingdao Port and the results show that the proposed method significantly outperforms ANN,SARIMA,and PPR models.展开更多
基金supported by China Meteorological Administration R & D Special Fund for Public Welfare (Meteorology) (Grant Nos. GYHY200906018 and GYHY200906015)the National Natural Science Foundation of China (Grant No.41005051)the National Key Technologies R & D Program of China (Grant No. 2009BAC51B05)
文摘A combination of the optimal subset regression (OSR) approach,the coupled general circulation model of the National Climate Center (NCC-CGCM) and precipitation observations from 160 stations over China is used to construct a statistical downscaling forecast model for precipitation in summer.Retroactive forecasts are performed to assess the skill of statistical downscaling during the period from 2003 to 2009.The results show a poor simulation for summer precipitation by the NCCCGCM for China,and the average spatial anomaly correlation coefficient (ACC) is 0.01 in the forecast period.The forecast skill can be improved by OSR statistical downscaling,and the OSR forecast performs better than the NCC-CGCM in most years except 2003.The spatial ACC is more than 0.2 in the years 2008 and 2009,which proves to be relatively skillful.Moreover,the statistical downscaling forecast performs relatively well for the main rain belt of the summer precipitation in some years,including 2005,2006,2008,and 2009.However,the forecast skill of statistical downscaling is restricted to some extent by the relatively low skill of the NCCCGCM.
文摘Background Atrial fibrillation (AF) catheter ablation has emerged as a promising treatment strategy for AF, but has not been widely adopted in the elderly population. The present study aimed to determine the safety and efficacy of AF catheter ablation in the elderly popula-tion. Methods and Results The study population consisted of 316 patients with paroxysmal AF who underwent left atrial ablation. Ninety-five patients were≥65 years (48 males, mean age 68.9 ± 3.0 years old) and 221 patients were〈65 years old (130 males, mean age 52.5 ± 10.4 years old). After a mean follow-up period of 34.0 ± 15.1 months, 55 (57.9%) patients in the elderly group were free from ar-rhythmia recurrence compared with 149 (67.4%) patients in the younger group (P=0.169). Procedural complications were uncommon in both study groups. In logistic regression analysis, left atrial diameter (P=0.003), hypertension (P=0.001), dyslipidemia (P=0.039), and coronary artery disease (P=0.018) were independent predictors of AF recurrence in the elderly population. Conclusions Catheter ablation of AF is safe and effective in older patients. Invasive strategies should be considered as an alternative choice in symptomatic elderly patients with AF.
文摘The occurrence and the detection system of mesophilic and psychrotrophic aerobic sporulating microorganisms (MPAS) in raw cow's milk were studied. Samples of raw cow's bulk tank milk were taken 21 times in 14 farms during one year. Basis of the method for MPAS assessment is the milk sample inactivation at the temperature 80-82 ℃ for 30 minutes followed by incubation in cultivation dishes at 30 -4- 1 ℃ for 3 days-mesophilic aerobic sporulates (MAS), and at 6.5 .4- 1 ℃ for 10 days-psychrotrophic aerobic sporulates (PAS). The total count of MPAS was within the span 2.5-340 CFU/mL (colony forming units). Average plate count of MPAS was 59.4 CFU/mL with variation coefficient 93.1%. MPAS count found in the same dishes at incubation for mesophilic and subsequently strictly psychrophilic microorganisms (MAS + SPAS) which enables to exclude overestimation of results by sporulates able to grow at both incubation temperatures was on average 56.9 CFU/mL what represents 95.8% out of the number of sums of individual dishes at two temperatures (MAS + PAS). Correlation coefficient of these two types of results r = 0.99 gives evidence of close dependence that is expressed by linear regression equation y = 0.9773x. We can consider the method using at first 30 .4- 1 ℃ and subsequently 6.5 -4-1℃ (MAS + SPAS) as more correct than the method with the opposite order of cultivation temperatures because of better regression coefficient of linear dependence and higher correlation coefficient in relation to the sum of independent incubations (MAS + PAS).
文摘In this paper, the authors explore the potential of several popular equalization techniques while overcoming their disadvantages. First, extensive literature survey on equalization is conducted. The focus is on popular linear equalization algorithms such as the conventional least mean square (LMS ) algorithm, the recursive least squares ( RLS ) algorithm, the filtered X LMS algorithm and their development. To overcome the slow convergence problem while keeping the simplicity of the LMS based algorithms, an H 2 optimal initialization is proposed.
基金Supported by The National Key Technology R&D Program(No.2013BAD13B01)the National High Technology Research and Development Program of China(No.2001AA633060)
文摘Air temperature and relative humidity have been the main parameters of meteorology study. In the past data could be obtained from in-situ observations, but the observations are local and sparse, especially over ocean. Now we can get them from satellites, yet it is hard to estimate them from sat- ellites directly so far. This paper presents a new method to retrieve monthly averaged sea air temper- ature (SAT) and relative humidity (RH) near sea surface from satellite data with artificial neural networks (ANN). Compared with the observations in Pacific and Atlantic, the root mean square (RMS) and the correlation between the estimated SAT and the observations are about 0.91 ~C and 0.99, respectively. The RMS and the correlation of RH are about 3.73% and 0.65, respectively. Compared with the multiple regression method, the ANN methodology is more powerful in building nonlinear relations in this research. Thus the global monthly average SAT and RH are retrieved from the fixed ANN network from July 1987 to May 2004. In general the annual average SAT shows the increasing trend in recent 18 years. The abnormality of SAT is decomposed with the empirical or- thogonal function (EOF). The leading three EOFs could explain 84% of the total variation. EOF1 (76.1%) presents the seasonal change of the SAT abnormality. EOF2 (4.6%) is mainly related with ENSO. EOF3 (3.3%) shows some new interesting phenomena appearing in the three main currents in Pacific, Atlantic and Indian Ocean.
基金supported by the National Natural Science Foundation of China (Grant No. 40930637)Special Project for Earthquake Science(Grant No. 200808079)Subject Foundation of Ministry of Education for Doctor Candidates in Universities (Grant No. 20100022110001)
文摘Changes in barometric pressure can affect the micro-dynamic state of groundwater level.The groundwater level data carry a lot of important information of tectonic activity and earthquakes.It is very significant to eliminate the barometric pressure effects from the groundwater level data in order to recognize seismic anomalies effectively.With the analysis of the main influential constituents of barometric pressure and their changes,we can have a better understanding of the changes of the aquifer medium,which can provide useful information for earthquake prediction.Taking the May 12,2008 Wenchuan earthquake as an example,this paper deals with the influence of barometric pressure on groundwater level based on observational data from Nanxi,Qionglai and Chaohu wells.The methods of the linear regression and the deconvolution regression were employed to remove the barometric pressure from the groundwater level data.The harmonic analysis and the spectral analysis were used to recognize the main influential waves of barometric pressure effect.A comparison was conducted on the main influential waves before and after the earthquake.The results showed that the main influential waves of barometric pressure effect changed and the amplitudes of all constituents also changed.This phenomenon may result from the characteristics of the influential constituents of pressure,or from the changes of the aquifer medium,which were caused by the earthquake.
文摘This paper proposes a hybrid forecasting method to forecast container throughput of Qingdao Port.To eliminate the influence of outliers,local outlier factor(lof) is extended to detect outliers in time series,and then different dummy variables are constructed to capture the effect of outliers based on domain knowledge.Next,a hybrid forecasting model combining projection pursuit regression(PPR) and genetic programming(GP) algorithm is proposed.Finally,the hybrid model is applied to forecasting container throughput of Qingdao Port and the results show that the proposed method significantly outperforms ANN,SARIMA,and PPR models.