This paper provides methods for assessing the precision of cost elasticity estimates when the underlying regression function is assumed to be polynomial. Specifically, the paper adapts two well-known methods for compu...This paper provides methods for assessing the precision of cost elasticity estimates when the underlying regression function is assumed to be polynomial. Specifically, the paper adapts two well-known methods for computing confidential intervals for ratios: the delta-method and the Fieller method. We show that performing the estimation with mean-centered explanatory variables provides a straightforward way to estimate the elasticity and compute a confidence interval for it. A theoretical discussion of the proposed methods is provided, as well as an empirical example based on publicly available postal data. Possible areas of application include postal service providers worldwide, transportation and electricity.展开更多
Based on gridded Argo profile data from January 2004 to December 2010, together with the P-vector inverse method, the three-dimensional structure, annual and inter-annual variations in volume of the Western Pacific Wa...Based on gridded Argo profile data from January 2004 to December 2010, together with the P-vector inverse method, the three-dimensional structure, annual and inter-annual variations in volume of the Western Pacific Warm Pool （WPWP） are studied. The variations of latitudinal and longitudinal warm water flowing into and out of the WPWP and the probable mecha- nism of warm water maintenance are also discussed. From the surface to the bottom, climatic WPWP tilts southward and its area decreases. The maximum depth could extend to 120 m, such that its volume could attain 1.86x10^5 m3. Annual variation of the WPWP volume shows two obvious peaks that occur in June and October, whereas its inter-annual variations are related to ENSO events. Based on a climatic perspective, the warm water flowing latitudinally into the pool is about 52 Sv, which is mainly through upper layers and via the eastern boundary. Latitudinally, warm water flowing outward is about 49 Sv, and this is mainly through lower layers and via the western boundary. In contrast, along the latitude, warm water flowing into and out of the pool is about 28 Sv and 23 Sv, respectively. Annual and inter-annual variations of the net transportation of the warm water demonstrate that the WPWP mainly loses warm water in the west-east direction, whereas it receives warm water from the north-south direction. The annual variation of the volume of WPWP is highly related to the annual variation of the net warm water transportation, however, they are not closely related on inter-annual time scale. On the inter-annual time scale, in- fluences of ENSO events on the net warm water transportation in the north-south direction are much more than that in the west-east direction. Although there are some limitations and simplifications when using the P-vector method, it could still help improve our understanding of the WPWP, especially regarding the sources of the warm water.展开更多
Objective To explore the application effect of goal-directed fluid therapy(GDFT)on laparoscopic liver resection.Methods From July 2023 to December 2023,48 patients who underwent laparoscopic liver resection were rando...Objective To explore the application effect of goal-directed fluid therapy(GDFT)on laparoscopic liver resection.Methods From July 2023 to December 2023,48 patients who underwent laparoscopic liver resection were randomly divided into the GDFT group and the CLCVP(controlled low central venous pressure)group.The patients in the GDFT group were guided by stroke volume variability(SVV)during surgery,while those in the CLCVP group were guided by a controlled low central venous pressure technique during fluid replacement surgery.Intraoperative bleeding volume,fluid replacement volume,urine output,liver blood flow obstruction time,postoperative exhaust time,length of hospital stays,and incidence of complications were recorded and compared between the two groups of patients.Results There was a difference between the two groups in terms of crystal fluid,colloid fluid,total fluid volume,and urine volume(P>0.05).However,the bleeding volume in the GDFT group(515.61±246.71)mL was lower than that in the CLCVP group(389.37±187.35)mL(P<0.05);and the blockade time of liver blood flow in the GDFT group(46.33±7.26)min was shorter than that of the CLCVP group(41.84±6.24)min(P<0.05);the postoperative exhaust time of patients in the GDFT group(4.86±1.24)d was shorter than that of patients in the CLCVP group(6.42±1.05)d(P<0.05);the hospitalization days of patients in the GDFT group(9.21±2.15)d were fewer than those in the CLCVP group(11.04±4.29)d(P<0.05).There were no statistically significant differences in the incidence of postoperative complications between the two groups of patients(P>0.05).Conclusion GDFT guided by SVV can stabilize intraoperative hemodynamics in patients undergoing laparoscopic liver resection,reduce intraoperative bleeding,and reduce liver blood flow blockage time.It is safer and more reliable than traditional fluid therapy.展开更多
文摘This paper provides methods for assessing the precision of cost elasticity estimates when the underlying regression function is assumed to be polynomial. Specifically, the paper adapts two well-known methods for computing confidential intervals for ratios: the delta-method and the Fieller method. We show that performing the estimation with mean-centered explanatory variables provides a straightforward way to estimate the elasticity and compute a confidence interval for it. A theoretical discussion of the proposed methods is provided, as well as an empirical example based on publicly available postal data. Possible areas of application include postal service providers worldwide, transportation and electricity.
基金supported by the Special Program for the National Basic Research (Grant No. 2012FY112300)SOED HPCC of the Second Institute of Oceanography, State Oceanic Administration for support and assistance
文摘Based on gridded Argo profile data from January 2004 to December 2010, together with the P-vector inverse method, the three-dimensional structure, annual and inter-annual variations in volume of the Western Pacific Warm Pool （WPWP） are studied. The variations of latitudinal and longitudinal warm water flowing into and out of the WPWP and the probable mecha- nism of warm water maintenance are also discussed. From the surface to the bottom, climatic WPWP tilts southward and its area decreases. The maximum depth could extend to 120 m, such that its volume could attain 1.86x10^5 m3. Annual variation of the WPWP volume shows two obvious peaks that occur in June and October, whereas its inter-annual variations are related to ENSO events. Based on a climatic perspective, the warm water flowing latitudinally into the pool is about 52 Sv, which is mainly through upper layers and via the eastern boundary. Latitudinally, warm water flowing outward is about 49 Sv, and this is mainly through lower layers and via the western boundary. In contrast, along the latitude, warm water flowing into and out of the pool is about 28 Sv and 23 Sv, respectively. Annual and inter-annual variations of the net transportation of the warm water demonstrate that the WPWP mainly loses warm water in the west-east direction, whereas it receives warm water from the north-south direction. The annual variation of the volume of WPWP is highly related to the annual variation of the net warm water transportation, however, they are not closely related on inter-annual time scale. On the inter-annual time scale, in- fluences of ENSO events on the net warm water transportation in the north-south direction are much more than that in the west-east direction. Although there are some limitations and simplifications when using the P-vector method, it could still help improve our understanding of the WPWP, especially regarding the sources of the warm water.
基金Hunan Provincial Health Commission Project(NO.202104011283,202214023133)Natural Science Foundation of Hunan Provincial(NO.kq2202436)Hunan Province Innovation Guidance Project(NO.2021SK50920)。
文摘Objective To explore the application effect of goal-directed fluid therapy(GDFT)on laparoscopic liver resection.Methods From July 2023 to December 2023,48 patients who underwent laparoscopic liver resection were randomly divided into the GDFT group and the CLCVP(controlled low central venous pressure)group.The patients in the GDFT group were guided by stroke volume variability(SVV)during surgery,while those in the CLCVP group were guided by a controlled low central venous pressure technique during fluid replacement surgery.Intraoperative bleeding volume,fluid replacement volume,urine output,liver blood flow obstruction time,postoperative exhaust time,length of hospital stays,and incidence of complications were recorded and compared between the two groups of patients.Results There was a difference between the two groups in terms of crystal fluid,colloid fluid,total fluid volume,and urine volume(P>0.05).However,the bleeding volume in the GDFT group(515.61±246.71)mL was lower than that in the CLCVP group(389.37±187.35)mL(P<0.05);and the blockade time of liver blood flow in the GDFT group(46.33±7.26)min was shorter than that of the CLCVP group(41.84±6.24)min(P<0.05);the postoperative exhaust time of patients in the GDFT group(4.86±1.24)d was shorter than that of patients in the CLCVP group(6.42±1.05)d(P<0.05);the hospitalization days of patients in the GDFT group(9.21±2.15)d were fewer than those in the CLCVP group(11.04±4.29)d(P<0.05).There were no statistically significant differences in the incidence of postoperative complications between the two groups of patients(P>0.05).Conclusion GDFT guided by SVV can stabilize intraoperative hemodynamics in patients undergoing laparoscopic liver resection,reduce intraoperative bleeding,and reduce liver blood flow blockage time.It is safer and more reliable than traditional fluid therapy.
