To create a new prediction model, the unbiased GM （1,1） model is optimized by the five-point slide method in this paper. Then, based on the occurrence areas of dce blast in Enshi District during 1995 -2004, the new ...To create a new prediction model, the unbiased GM （1,1） model is optimized by the five-point slide method in this paper. Then, based on the occurrence areas of dce blast in Enshi District during 1995 -2004, the new model and unbiased GM （1, 1 ） model are applied to predict the occurrence areas of rice blast during 2005 -2010. Predicting outcomes show that the prediction accuracy of five-point unbiased sliding optimized GM （1, 1 ） model is higher than the unbiased GM （1,1） model. Finally, combined with the prediction results, the author provides some suggestion for Enshi District in the prevention and control of rice blast in 2010.展开更多
In order to verify the feasibility and stability of a degree-day model on simulating the long time series of glacier mass balance, we apply a degree-day model to simulate the mass balance of Urumqi Glacier No. 1 for t...In order to verify the feasibility and stability of a degree-day model on simulating the long time series of glacier mass balance, we apply a degree-day model to simulate the mass balance of Urumqi Glacier No. 1 for the period 1987/1988-2007/2008 based on temperature and precipitation data from a nearby climate station. The model is calibrated by simulating point measurements of mass bal- ance, mass balance profiles, and mean specific mass balance during 1987/1988-1996/1997. The opti- mized parameters are obtained by using a least square method to make the model fit the measured mass balance through the model calibration. The model validation （1997/1998-2007/2008） indicates that the modeled results are in good agreement with the observations. The static mass balance sensitiv- ity of Urumqi Glacier No. 1 is analyzed by computing the mass balance of the glacier for a temperature increase of 1℃, with and without a 5% precipitation increase, and the values for the east branch are -0.80 and -0.87 m w.e. a-1℃-1, respectively, and for the west branch, the values are -0.68 and -0.74 m w.e. a-1℃-1, respectively. Moreover, the analysis of the parameter stability indicates that the parame- ters in the model determined from the current climate condition can be applied in the prediction of the future mass balance changes for the glacier and provide a reference for extending the model to other small glaciers in western China.展开更多
Extensive iron deposition has been observed in the midbrain substantia nigra （SN） of Parkinson＇s disease （PD） patients, but the mechanisms of iron deposition in the SN remain poorly understood. The present study ...Extensive iron deposition has been observed in the midbrain substantia nigra （SN） of Parkinson＇s disease （PD） patients, but the mechanisms of iron deposition in the SN remain poorly understood. The present study investigated the relationship between dopaminergic neuronal damage, iron content changes, and divalent metal transporter 1 （DMT1） in the midbrain SN of PD rats to explore the relationship between time of iron deposition and DMT1 expression. Frozen midbrain SN sections from model rats were stained with Perls＇ iron. Results showed massive loss of tyrosine hydroxylase （TH）-positive cells in the SN and increased DMT1 expression in model group rats. No obvious iron deposition was observed in the SN during early stages after damage, but significant iron deposition was detected at 8 weeks post-injury. Results demonstrate that the loss of TH-positive cells in the SN appeared simultaneously with increased DMT1 expression. Extensive iron deposition occurred at 8 weeks post injury, which could be regarded as an early time window of iron deposition.展开更多
By studying the spectral properties of the underlying operator corresponding to the M/G/1 queueing model with optional second service we obtain that the time-dependent solution of the model strongly converges to its s...By studying the spectral properties of the underlying operator corresponding to the M/G/1 queueing model with optional second service we obtain that the time-dependent solution of the model strongly converges to its steady-state solution. We also show that the time-dependent queueing size at the departure point converges to the corresponding steady-state queueing size at the departure point.展开更多
This paper expresses the efficient outputs of decisionmaking unit（DMU） as the sum of ＂average outputs＂ forecasted by a GM（1,N） model and ＂increased outputs＂ which reflect the difficulty to realize efficient ou...This paper expresses the efficient outputs of decisionmaking unit（DMU） as the sum of ＂average outputs＂ forecasted by a GM（1,N） model and ＂increased outputs＂ which reflect the difficulty to realize efficient outputs.The increased outputs are solved by linear programming using data envelopment analysis efficiency theories,wherein a new sample is introduced whose inputs are equal to the budget in the issue No.n ＋ 1 and outputs are forecasted by the GM（1,N） model.The shortcoming in the existing methods that the forecasted efficient outputs may be less than the possible actual outputs according to developing trends of input-output rate in the periods of pre-n is overcome.The new prediction method provides decision-makers with more decisionmaking information,and the initial conditions are easy to be given.展开更多
The spin-1 Blume–Capel model with transverse and longitudinal external magnetic fields h, in addition to a longitudinal random crystal field D, is studied in the mean-field approximation. It is assumed that the cryst...The spin-1 Blume–Capel model with transverse and longitudinal external magnetic fields h, in addition to a longitudinal random crystal field D, is studied in the mean-field approximation. It is assumed that the crystal field is either turned on with probability p or turned off with probability 1 p on the sites of a square lattice. Phase diagrams are then calculated on the reduced temperature crystal field planes for given values of γ=Ω/J and p at zero h. Thus, the effect of changing γ and p are illustrated on the phase diagrams in great detail and interesting results are observed.展开更多
In this paper, we use Monte Carlo simulations to compare parametric estimators of Type 1 Tobit model. In particular, we examine the performance for finite samples of three different estimators of simple Tobit model: t...In this paper, we use Monte Carlo simulations to compare parametric estimators of Type 1 Tobit model. In particular, we examine the performance for finite samples of three different estimators of simple Tobit model: the least squares (LS) estimator, the Heckman (H) estimator and the maximum likelihood (ML) estimator. These three estimators are consistent and asymptotically normal in the case where the density error is specified. However, these properties are sensitive to the situation where the error distribution is not specified. The purpose of this article is to determine properties of the three estimators, namely bias and convergence, by using Monte Carlo simulations.展开更多
GM(1, 1) is generally used in Grey System Theory which constructs an Ordinary Differential Equation for given se-ries. It is effective for monotone series, and its simulating effect is good and error is small. However...GM(1, 1) is generally used in Grey System Theory which constructs an Ordinary Differential Equation for given se-ries. It is effective for monotone series, and its simulating effect is good and error is small. However, If the series dosen’ t havea property of monotone, the simulating effect of GM(1,1) is not fine, and its error gets bigger. In this paper, we use GM(2,1) to handle the oxcillation series, which uses the Method of Minimum Squares in determining the uncertain parameters.展开更多
BACKGROUND:The specificity in discriminating pancreatitis is limited in the positron emission tomography(PET)using Fluorine-18-fluorodeoxyglucose.Furthermore,PET is not widely available compared to the single photon e...BACKGROUND:The specificity in discriminating pancreatitis is limited in the positron emission tomography(PET)using Fluorine-18-fluorodeoxyglucose.Furthermore,PET is not widely available compared to the single photon emission computed tomography(SPECT).Since amino acids play a minor role in metabolism of inflammatory cells,the potential of the SPECT tracer,3-[ 123 I]iodo-L-α-methyltyrosine(123I-IMT),for detecting pancreatic cancer was examined in xenotransplantation models of human pancreatic carcinoma in mice. METHODS: 123 I-IMT was injected to eight mice inoculated with subcutaneous or orthotopic pancreatic tumors.Fused high-resolution-micro-SPECT(Hi-SPECT)and magnetic resonance imaging were performed.The gene expression level of L amino acid transport-system 1(LAT1)was analyzed and correlated with tumor uptake of 123 I-IMT. RESULTS:A high uptake of 123 I-IMT was detected in all tumor-bearing mice.The median tumor-to-background ratio (T/B)was 12.1(2.0-13.2)for orthotopic and 8.4(1.8-11.1)for subcutaneous xenotransplantation,respectively.Accordingly, the LAT1 expression in transplanted Colo357 cells was increased compared to non-malignant controls.CONCLUSIONS:Our mouse model could show a high 123 I-IMT uptake in pancreatic cancer.Fused MRI scans facilitate precise evaluation of uptake in the specific regions of interest.Further studies are required to confirm these findings in tumors derived from other human pancreatic cancer cells.Since amino acids play a minor role in the metabolism of inflammatory cells,the potential for application of 123 I-IMT to distinguish pancreatic tumor from inflammatory pancreatitis warrants further investigation.展开更多
Because the impacts of the factors such as some disturbances are graduallyadded into the system, the grey forecast results will deviate from the systemtrue value. To improve the forecast precision, Pro-Dens Julons pro...Because the impacts of the factors such as some disturbances are graduallyadded into the system, the grey forecast results will deviate from the systemtrue value. To improve the forecast precision, Pro-Dens Julons provided twomethfor-But they had not consider the impact of artificial disturbance. LiZhihua et al. of Qinghua Univ. presented another method. This paper revisesthe method and make it be a spocial case.展开更多
112 short-period seismographs were set up in the 400 km^2 area of Pingtan Island and its surrounding areas in Fujian.The combined observations of the airgun source and ambient noise source were carried out using a den...112 short-period seismographs were set up in the 400 km^2 area of Pingtan Island and its surrounding areas in Fujian.The combined observations of the airgun source and ambient noise source were carried out using a dense array to receive the 387 airgun signals excited around the island and one month of continuous ambient noise recording.The 1-D P-wave and S-wave shallow velocity model of Pingtan Island is obtained by the inversion of the airgun body wave’s first arrival time data,and the reliability of the velocity model is verified by using the surface wave phase velocity dispersion curve,which can provide initial model for subsequent 3-D imaging.The experimental results show that this experiment is a successful demonstration of local scale green non-destructive detection,which can provide basic data for shallow surface structure research and strong vibration simulation of the Pingtan Island.展开更多
基金Supported by Science Research Project of Department of Education of Hubei Province (B20092901)~~
文摘To create a new prediction model, the unbiased GM （1,1） model is optimized by the five-point slide method in this paper. Then, based on the occurrence areas of dce blast in Enshi District during 1995 -2004, the new model and unbiased GM （1, 1 ） model are applied to predict the occurrence areas of rice blast during 2005 -2010. Predicting outcomes show that the prediction accuracy of five-point unbiased sliding optimized GM （1, 1 ） model is higher than the unbiased GM （1,1） model. Finally, combined with the prediction results, the author provides some suggestion for Enshi District in the prevention and control of rice blast in 2010.
基金supported by the Knowledge Innovation Project of the Chinese Academy of Sciences (No. KZCX2-EW-311)the National Basic Research Program of China (No. 2007CB411501)the National Natural Science Foundation of China (Nos. 1141001040, J0930003/J0109)
文摘In order to verify the feasibility and stability of a degree-day model on simulating the long time series of glacier mass balance, we apply a degree-day model to simulate the mass balance of Urumqi Glacier No. 1 for the period 1987/1988-2007/2008 based on temperature and precipitation data from a nearby climate station. The model is calibrated by simulating point measurements of mass bal- ance, mass balance profiles, and mean specific mass balance during 1987/1988-1996/1997. The opti- mized parameters are obtained by using a least square method to make the model fit the measured mass balance through the model calibration. The model validation （1997/1998-2007/2008） indicates that the modeled results are in good agreement with the observations. The static mass balance sensitiv- ity of Urumqi Glacier No. 1 is analyzed by computing the mass balance of the glacier for a temperature increase of 1℃, with and without a 5% precipitation increase, and the values for the east branch are -0.80 and -0.87 m w.e. a-1℃-1, respectively, and for the west branch, the values are -0.68 and -0.74 m w.e. a-1℃-1, respectively. Moreover, the analysis of the parameter stability indicates that the parame- ters in the model determined from the current climate condition can be applied in the prediction of the future mass balance changes for the glacier and provide a reference for extending the model to other small glaciers in western China.
基金the Scientific Research Common Program of Beijing Municipal Commission of Education,No.KM200610025008
文摘Extensive iron deposition has been observed in the midbrain substantia nigra （SN） of Parkinson＇s disease （PD） patients, but the mechanisms of iron deposition in the SN remain poorly understood. The present study investigated the relationship between dopaminergic neuronal damage, iron content changes, and divalent metal transporter 1 （DMT1） in the midbrain SN of PD rats to explore the relationship between time of iron deposition and DMT1 expression. Frozen midbrain SN sections from model rats were stained with Perls＇ iron. Results showed massive loss of tyrosine hydroxylase （TH）-positive cells in the SN and increased DMT1 expression in model group rats. No obvious iron deposition was observed in the SN during early stages after damage, but significant iron deposition was detected at 8 weeks post-injury. Results demonstrate that the loss of TH-positive cells in the SN appeared simultaneously with increased DMT1 expression. Extensive iron deposition occurred at 8 weeks post injury, which could be regarded as an early time window of iron deposition.
基金supported by the National Natural Science Foundation of China(11371303)Natural Science Foundation of Xinjiang(2012211A023)Science Foundation of Xinjiang University(XY110101)
文摘By studying the spectral properties of the underlying operator corresponding to the M/G/1 queueing model with optional second service we obtain that the time-dependent solution of the model strongly converges to its steady-state solution. We also show that the time-dependent queueing size at the departure point converges to the corresponding steady-state queueing size at the departure point.
基金supported by the Research Start Funds for Introducing High-level Talents of North China University of Water Resources and Electric Power
文摘This paper expresses the efficient outputs of decisionmaking unit（DMU） as the sum of ＂average outputs＂ forecasted by a GM（1,N） model and ＂increased outputs＂ which reflect the difficulty to realize efficient outputs.The increased outputs are solved by linear programming using data envelopment analysis efficiency theories,wherein a new sample is introduced whose inputs are equal to the budget in the issue No.n ＋ 1 and outputs are forecasted by the GM（1,N） model.The shortcoming in the existing methods that the forecasted efficient outputs may be less than the possible actual outputs according to developing trends of input-output rate in the periods of pre-n is overcome.The new prediction method provides decision-makers with more decisionmaking information,and the initial conditions are easy to be given.
文摘The spin-1 Blume–Capel model with transverse and longitudinal external magnetic fields h, in addition to a longitudinal random crystal field D, is studied in the mean-field approximation. It is assumed that the crystal field is either turned on with probability p or turned off with probability 1 p on the sites of a square lattice. Phase diagrams are then calculated on the reduced temperature crystal field planes for given values of γ=Ω/J and p at zero h. Thus, the effect of changing γ and p are illustrated on the phase diagrams in great detail and interesting results are observed.
文摘In this paper, we use Monte Carlo simulations to compare parametric estimators of Type 1 Tobit model. In particular, we examine the performance for finite samples of three different estimators of simple Tobit model: the least squares (LS) estimator, the Heckman (H) estimator and the maximum likelihood (ML) estimator. These three estimators are consistent and asymptotically normal in the case where the density error is specified. However, these properties are sensitive to the situation where the error distribution is not specified. The purpose of this article is to determine properties of the three estimators, namely bias and convergence, by using Monte Carlo simulations.
文摘GM(1, 1) is generally used in Grey System Theory which constructs an Ordinary Differential Equation for given se-ries. It is effective for monotone series, and its simulating effect is good and error is small. However, If the series dosen’ t havea property of monotone, the simulating effect of GM(1,1) is not fine, and its error gets bigger. In this paper, we use GM(2,1) to handle the oxcillation series, which uses the Method of Minimum Squares in determining the uncertain parameters.
基金supported in part by a BMBF grant(TOMCAT)given to H.K.the Molecular Imaging North Competence Center(MOIN-CC)
文摘BACKGROUND:The specificity in discriminating pancreatitis is limited in the positron emission tomography(PET)using Fluorine-18-fluorodeoxyglucose.Furthermore,PET is not widely available compared to the single photon emission computed tomography(SPECT).Since amino acids play a minor role in metabolism of inflammatory cells,the potential of the SPECT tracer,3-[ 123 I]iodo-L-α-methyltyrosine(123I-IMT),for detecting pancreatic cancer was examined in xenotransplantation models of human pancreatic carcinoma in mice. METHODS: 123 I-IMT was injected to eight mice inoculated with subcutaneous or orthotopic pancreatic tumors.Fused high-resolution-micro-SPECT(Hi-SPECT)and magnetic resonance imaging were performed.The gene expression level of L amino acid transport-system 1(LAT1)was analyzed and correlated with tumor uptake of 123 I-IMT. RESULTS:A high uptake of 123 I-IMT was detected in all tumor-bearing mice.The median tumor-to-background ratio (T/B)was 12.1(2.0-13.2)for orthotopic and 8.4(1.8-11.1)for subcutaneous xenotransplantation,respectively.Accordingly, the LAT1 expression in transplanted Colo357 cells was increased compared to non-malignant controls.CONCLUSIONS:Our mouse model could show a high 123 I-IMT uptake in pancreatic cancer.Fused MRI scans facilitate precise evaluation of uptake in the specific regions of interest.Further studies are required to confirm these findings in tumors derived from other human pancreatic cancer cells.Since amino acids play a minor role in the metabolism of inflammatory cells,the potential for application of 123 I-IMT to distinguish pancreatic tumor from inflammatory pancreatitis warrants further investigation.
文摘Because the impacts of the factors such as some disturbances are graduallyadded into the system, the grey forecast results will deviate from the systemtrue value. To improve the forecast precision, Pro-Dens Julons provided twomethfor-But they had not consider the impact of artificial disturbance. LiZhihua et al. of Qinghua Univ. presented another method. This paper revisesthe method and make it be a spocial case.
基金sponsored by the Key Technologies R&D Program of Fujian Earthquake Agency(G201703)the Seismic Science and Technology Spark Program,CEA(XH19023Y)
文摘112 short-period seismographs were set up in the 400 km^2 area of Pingtan Island and its surrounding areas in Fujian.The combined observations of the airgun source and ambient noise source were carried out using a dense array to receive the 387 airgun signals excited around the island and one month of continuous ambient noise recording.The 1-D P-wave and S-wave shallow velocity model of Pingtan Island is obtained by the inversion of the airgun body wave’s first arrival time data,and the reliability of the velocity model is verified by using the surface wave phase velocity dispersion curve,which can provide initial model for subsequent 3-D imaging.The experimental results show that this experiment is a successful demonstration of local scale green non-destructive detection,which can provide basic data for shallow surface structure research and strong vibration simulation of the Pingtan Island.
