To better assimilate Advanced TIROS Operational Vertical Sounder(ATOVS) radiance data and provide more accurate initial fields for a numerical model,two bias correction schemes are employed to correct the ATOVS radian...To better assimilate Advanced TIROS Operational Vertical Sounder(ATOVS) radiance data and provide more accurate initial fields for a numerical model,two bias correction schemes are employed to correct the ATOVS radiance data.The difference in the two schemes lies in the predictors use in air-mass bias correction.The predictors used in SCHEME 1 are all obtained from model first-guess,while those in SCHEME 2 are from model first-guess and radiance observations.The results from the two schemes show that after bias correction,the observation residual became smaller and closer to a Gaussian distribution.For both land and ocean data sets,the results obtained from SCHEME 1 are similar to those from SCHEME 2,which indicates that the predictors could be used in bias correction of ATOVS data.展开更多
This paper investigates the traffic accidents＇ trends and causes in Dubai. For this purpose, the traffic accident statistics for years 2003 to 2012 are used to examine the trends of different types of accidents and t...This paper investigates the traffic accidents＇ trends and causes in Dubai. For this purpose, the traffic accident statistics for years 2003 to 2012 are used to examine the trends of different types of accidents and the causes of these accidents. Also, the paper determines the most common types of accidents over the study period and identifies some of the causes for these accidents. Furthermore, the paper shows the impact of the new traffic law amendments, which were issued in 2008, on the accident rates and trends. The results showed that the implementation of the traffic law amendments did not have major impact in year 2008. However, there was a significant effect of these amendments in the following years. Also, lack of awareness of traffic laws and regulations in Dubai has been proven to be one of the major causes of accidents. Finally, the paper provides some recommendations to reduce the traffic accident rates, in order to achieve the Dubai Police Department 2020 strategic goal to have zero fatalities.展开更多
This study models supply response for major agricultural crops in Nigeria which include the standard arguments and price risk. The data comes from Central Bank of Nigeria annual reports and statement of account, Natio...This study models supply response for major agricultural crops in Nigeria which include the standard arguments and price risk. The data comes from Central Bank of Nigeria annual reports and statement of account, National Bureau of Statistics＇ abstract of statistics and annual Agricultural survey manual. The data are analyzed using autoregressive distributed lag and cointegration and error correction models. The results indicate that producers are responsive not only to price but also to price risk and exchange rate.展开更多
We obtain the instanton correction recursion relations for the low energy effective prepotential in pure Ν = 2SU(n) supersymmetric Yang-Mills gauge theory from Whitham hierarchy and Seiberg-Witten/Whitham equations. ...We obtain the instanton correction recursion relations for the low energy effective prepotential in pure Ν = 2SU(n) supersymmetric Yang-Mills gauge theory from Whitham hierarchy and Seiberg-Witten/Whitham equations. These formulae provide us a powerful tool to calculate arbitrary order instanton corrections coefficients from the perturbative contributions of the effective prepotential in Seiberg-Witten gauge theory. We apply this idea to evaluate one-and two-order instanton corrections coefficients explicitly in SU(n) case in detail through the dynamical scale parameter expressed in terms of Riemann's theta-function.展开更多
基金National Natural Science Foundation of China (40875021, 40930951)Knowledge Innovation Program of Chinese Academy of Sciences ( KZCX2-YW-Q03-3)
文摘To better assimilate Advanced TIROS Operational Vertical Sounder(ATOVS) radiance data and provide more accurate initial fields for a numerical model,two bias correction schemes are employed to correct the ATOVS radiance data.The difference in the two schemes lies in the predictors use in air-mass bias correction.The predictors used in SCHEME 1 are all obtained from model first-guess,while those in SCHEME 2 are from model first-guess and radiance observations.The results from the two schemes show that after bias correction,the observation residual became smaller and closer to a Gaussian distribution.For both land and ocean data sets,the results obtained from SCHEME 1 are similar to those from SCHEME 2,which indicates that the predictors could be used in bias correction of ATOVS data.
文摘This paper investigates the traffic accidents＇ trends and causes in Dubai. For this purpose, the traffic accident statistics for years 2003 to 2012 are used to examine the trends of different types of accidents and the causes of these accidents. Also, the paper determines the most common types of accidents over the study period and identifies some of the causes for these accidents. Furthermore, the paper shows the impact of the new traffic law amendments, which were issued in 2008, on the accident rates and trends. The results showed that the implementation of the traffic law amendments did not have major impact in year 2008. However, there was a significant effect of these amendments in the following years. Also, lack of awareness of traffic laws and regulations in Dubai has been proven to be one of the major causes of accidents. Finally, the paper provides some recommendations to reduce the traffic accident rates, in order to achieve the Dubai Police Department 2020 strategic goal to have zero fatalities.
文摘This study models supply response for major agricultural crops in Nigeria which include the standard arguments and price risk. The data comes from Central Bank of Nigeria annual reports and statement of account, National Bureau of Statistics＇ abstract of statistics and annual Agricultural survey manual. The data are analyzed using autoregressive distributed lag and cointegration and error correction models. The results indicate that producers are responsive not only to price but also to price risk and exchange rate.
基金Supported by the National Natural Science Foundation of China under Grant No.11271079
文摘We obtain the instanton correction recursion relations for the low energy effective prepotential in pure Ν = 2SU(n) supersymmetric Yang-Mills gauge theory from Whitham hierarchy and Seiberg-Witten/Whitham equations. These formulae provide us a powerful tool to calculate arbitrary order instanton corrections coefficients from the perturbative contributions of the effective prepotential in Seiberg-Witten gauge theory. We apply this idea to evaluate one-and two-order instanton corrections coefficients explicitly in SU(n) case in detail through the dynamical scale parameter expressed in terms of Riemann's theta-function.
